The School of Engineering, Computer Science and Mathematics website has been designed in line with modern Internet technologies (XHTML, CSS, DOM) but your browser does not appear to properly support some of the required features.
So that you are not at a disadvantage, you will still see all of the information content but in a less organised form. However, you will have a better browsing experience if you upgrade to a modern browser.
 
On coherenceincoherence transition in dynamical networks: spatial chaos and chimera states  
Yuri Maistrenko (Potsdam)  
19 Jul 2011  Harrison 170 Tuesday 10am  Applied Mathematics 
We discuss the breakdown of spatial coherence in networks of coupled oscillators with nonlocal interaction. By systematically analyzing the dependence of the spatiotemporal dynamics on the range and strength of coupling, we uncover a dynamical bifurcation scenario for the coherenceincoherence transition which starts with the appearance of narrow layers of incoherence occupying eventually the whole space. Our findings for coupled chaotic and periodic maps as well as for timecontinuous Ro¨ssler systems reveal that intermediate, partially coherent states represent characteristic spatiotemporal patterns at the transition from coherence to incoherence.  
 
The phaseamplitude description of neural oscillators.  
Kyle Wedgewood (University of Nottingham)  
11 Jul 2011  Harrison 170 Monday 2pm  Applied Mathematics 
It is quite common to describe neural oscillators with a phase variable, thus reducing the model description to that of dynamics on a circle. However, if a limit cycle is not strongly attracting then this reduction may poorly characterise behaviour of the original system. Here we consider a coordinate transformation to a phase amplitude framework that allows one to track the evolution of distance from the cycle as well as phase on cycle. A number of common models in computational neuroscience (primarily the MorrisLecar model) are revisited in this framework and their response to pulsatile current forcing is investigated. We highlight the differences between phase and phaseamplitude descriptions, and show that the former can miss some substantial features of neuronal response. Finally, we discuss extensions of this work to consider the effects of offcycle dynamics contributing to shearinduced chaos.  
 
Spatiotemporal GIS  
Prof. Christophe Claramunt (Naval Academy Research Institute, Brest, France)  
4 Jul 2011  Harrison 170 Monday 3pm  Computer Science 
TBA  
 
Decentralized spatial computing for geosensor networks, especially in movement analysis  
Dr Patrick Laube (Department of Geography, University of Zurich)  
4 Jul 2011  Harrison 170 Monday 4pm  Computer Science 
TBA  
 
Weather, climate and renewable energy  
David Brayshaw (University of Reading)  
23 Jun 2011  Harrison 209 Thursday 2pm  Applied Mathematics 
Securing a reliable electricity supply that is sufficient to meet demand is a vital concern for any modern economy. With the growth of renewable energy generation (particularly wind), it is important to understand the impacts of weather and climate variability on both supply and demand at national and international scales. At the daytoday level, discussion in the UK often focuses on the issue of windsupply during peak demand conditions – that is, the estimation of the minimum contribution that windpower will make during extreme demand periods. Recorded power system data alone is insufficient to robustly estimate this wind “capacity value”, leading to the emergence of a rather confused picture in both the energy systems literature and the wider public debate. Weatherclassification tools are proposed here as a means to address this problem. By identifying the relevant meteorological patterns associated with lowwinds and peakdemand, it is demonstrated that the prevailing view of an anticyclonic "lowwind coldsnap" does not adequately describe peakdemand conditions. At longer timescales, largescale lowfrequency variability in the climate system can also have a marked impact on renewable generation, a fact that is often ignored during resource assessment and wind integration studies. A simple example is the North Atlantic Oscillation (NAO), variations in which are capable of yielding a difference in mean windpower generation at UK sites of up to 10%. The NAO also correlates strongly with largescale variations in seasonalmean surface temperature and precipitation patterns, potentially affecting the demand for electricity and the availability of hydropower, as well as wind generation. Such largescale covariability is likely to become increasingly important as crossborder transports within the European energy system increase. This talk presents ongoing research which seeks to better explore the links between weather, climate and energy. It will highlight some of the areas where meteorological information can be used to inform decision making in the UK and European electricity systems.  
 
Why is the Arctic warming so fast?  
James Screen (University of Melbourne)  
21 Jun 2011  Harrison 102 Tuesday 2pm  Applied Mathematics 
Recent climate change has been especially pronounced in the Arctic region, with surface temperatures rising two to four times faster than the global average and an accompanying rapid decline of sea ice. Both the Arctic warming and the sea ice loss are unprecedented over at least the last few thousand years. A multitude of climate feedbacks have been proposed that amplify the Arctic surface temperature response to climate forcing. This talk will discuss some of these, and explore whether they are already active and contributing to recent Arctic change. It will present evidence that strong icetemperature feedbacks have emerged and that the decline in sea ice is playing a central role in Arctic temperature amplification. Both the sea ice loss and the warming have significant impacts on the Arctic moisture budget. These will be discussed in the context of changes in atmospheric water vapour content and in the phase of summer precipitation. There is evidence of humidity increases and a transition towards less snow and more rain. The causes, impacts, and feedbacks associated with these hydrological changes will be considered.  
 
TBA  
TBA  
16 Jun 2011  Harrison LT04 Thursday 2pm  Applied Mathematics 
 
Title: New Computational techniques for modeling Acoustic Fluids and Wave Propagation  
Professor S Gopalakrishnan (Department of Aerospace Engineering, Indian Institute of Science, Bangalore)  
9 Jun 2011  Harrison H170 (3D Visualisation Suite) Thursday 2pm  Advanced Technologies RI 
In this talk, new computational models for studying dynamics of acoustic fluids will be presented. The talk will cover two different computational models, namely the conventional finite elements and the frequency domain based spectral finite elements. Two different fluid finite element formulations based on Lagrangian frame of reference, one based on htype formulation and the second based on Legendre's time domain spectral elements will be presented in this talk. One of the problems associated with htype Lagrangian FEM is that they suffer from mesh locking problems due to fluid incompressibility. In addition to mesh locking problems, these elements exhibit a numerous zero energy eigen modes due to fluid circulation. To circumvent these zero energy modes, the fluid is made irrotational, which will further stiffen the formulated fluid element. Hence the formulated htype will suffer from two different constraints, one due to fluid incompressibility and the second due to fluid irrotationality. The main objective of the first part of the talk is to formulate Lagrangian htype FEM that is free from mesh locking due to twin constraints. In this work, formulation of both 2D and 3D elements will be presented. In the second part of the talk, Lagrangian FEM based on Lengendre's basis functions is presented. Here, it will be seen that the choice of different integration scheme for the volumetric stiffness and rotational stiffness will not only eliminate mesh locking, but also exhibit superior convergence property. The last part of the talk will address the formulation of Spectral FEM, especially for studying wave propagation in acoustic fluids. The talk will cover a number of examples that show the computational superiority of Spectral Fem over conventional FEM. The use of the formulated elements for fluidstructure interaction problems will be addressed in this talk.  
 
TBA  
TBA  
9 Jun 2011  Harrison LT04 Thursday 2pm  Applied Mathematics 
 
** postponed to 23rd June **  
David Brayshaw (University of Reading)  
2 Jun 2011  Harrison LT04 Thursday 2pm  Applied Mathematics 
** postponed to 23rd June **  
 
[symposium] Rotating Flow and Dynamo  
Taylor and Francis sponsored symposium  
2 Jun 2011  Harrison 215 Thursday from 11am  Applied Mathematics 
Thursday, 2 June, 2011 at Room 215 Harrison Building 11:0012:30 Tea/Coffee/Biscuits, Room 215 Harrison Building 12:302:00, Lunch at Xfi Building 2:002:30, Andrew Soward (Exeter) The onset of strongly localised thermal convection in rotating spherical shells. 2:303:00, Radostin Simitev (Glasgow), Effects of shell thickness and velocity boundary conditions on convective dynamos in rotating spherical shells. 3:003:30, Jun Zou (Hong Kong), Inverse Electromagnetic Obstacle Scattering. 3:304:30, Tea/Coffee/Biscuits, Room 215 Harrison Building; 4:305:00, Phil Livermore (Leeds) Dynamics of the tangent cylinder in rapidlyrotating inviscid flows, 5:005:30, Yannick Ponty (France) Large scale and small scale dynamos 5:306:00 Emilie Neveu (France) Multigrids for data assimilation on geophysics models 6:309:00 Conference dinner (the location to be confirmed) Friday, 3 June, 2011, at Room 215 Harrison Building 9:009:30 Steve Tobias (Leeds), Direct Statistical Simulation of Jet Formation 9:3010:00 Emmanuel Dormy (France), Weak and Strong Field Dynamos 10:0010:30 Paul Bushby (Newcastle), Dynamo action in rotating compressible convection 10:3011:00 Tea/Coffee/Biscuits, Room 215 Harrison Building; 11:0011:30 Keke Zhang (Exeter), Asymptotic solution for resonant flow in a spheroidal cavity driven by latitudinal libration. 11:3012:00 Michael Chan (Hong Kong), Fluid motion and dynamos in a triaxial cavity driven by libration 12:0013:30, Lunch at Xfi Building (THE END)  
 
 no seminar   
 no seminar   
26 May 2011  Harrison LT04 Thursday 2pm  Applied Mathematics 
 
Connecting mesoscale and macroscale models of cellular migration  
Ruth Baker (University of Oxford)  
19 May 2011  Harrison LT04 Thursday 2pm  Applied Mathematics 
Continuum, partial differential equation (PDE) descriptions of cell movement are often employed in modelling studies because of their analytical tractability, and the wealth of numerical methods available for their solution. Derived from, for example, conservation of mass approaches these models describe how cell density changes with time due to random movements of cells, different types of taxes/kineses and cell proliferation/death. In the main, these processes are represented in the model equations in a phenomenological manner, providing gross descriptions not necessarily derived from the underlying cell behaviour. In this talk I will consider effects such as cell shape and volume exclusion, discussing how such phenomena may be modelled at the mesoscale, and how populationlevel macroscale models may be derived from these descriptions.  
 
Title: Damage Tolerance Optimization of Tapered Composite Laminates  
Giuliano Allegri (Department of Aerospace Engineering, University of Bristol)  
12 May 2011  Harrison H170 (3D Visualisation Suite) Thursday 2pm  Advanced Technologies RI 
Tapering structural element is necessary in order to optimize specific stiffness and strength. Tapered metallic parts can be manufactured by casting or machining, whilst for fibre reinforced composites tapering always requires terminating, i.e. droppingoff, plies. Ply dropoffs act as stress raisers since they represent discontinuities for the laminate geometrical arrangement and elastic properties. Therefore ply terminations promote delamination and thus compromise the laminate strength and damage tolerance performance. An analytical solution for the calculation of the energy release rates associated with delaminations emanated from ply dropoffs has been developed and employed to optimize the termination sequences in tapered laminates for maximum damage tolerance performance under given geometric constraints. This optimization task has been proved to be analogous to the classical "travel salesman" problem, provided than a suitable fracture energy metric is introduced. Different optimization techniques have been employed, including genetic algorithms and simulated annealing with stochastic tunnelling. The optimization results can be synthesised in a set of "robust" design principles which have been implemented in a fuzzy logic framework in order to provide optimized configurations at limited computational costs.  
 
== COLLOQUIUM == Collective behaviour of swimming microorganisms  
Professor Tim Pedley (University of Cambridge)  
12 May 2011  Harrison LT04 Thursday 2pm  Applied Mathematics 
Suspensions of swimming microorganisms exhibit a rich variety of collective behaviour, such as the bioconvection patterns seen for suspensions of upswimming cells that are denser than their surroundings, or the timevarying coherent structures seen in dense suspensions of swimming bacteria. Here we investigate the fluid dynamic mechanisms underlying these patterns, by means of (1) a continuum model for dilute suspensions, (2) hydrodynamic interactions between pairs of model microorganisms, and (3) simulations and models for nondilute suspensions. The talk will conclude with recent observations of ‘dancing’ algae.  
 
Discrete Variational Derivative Methods for PDES  
Chris Budd  
9 May 2011  Harrison 203 Monday 2pm  Applied Mathematics 
 
Title: Developing a Strategic Framework for the Successful Implementation of Additive Manufacturing Technologies  
Stephen Mellor (Engineering, CEMPS, University of Exeter)  
5 May 2011  Harrison H170 (3D Visualisation Suite) Thursday 1pm  Advanced Technologies RI (Internal) 
It has long been understood that innovation in production technology can be used strategically as a powerful competitive weapon, enabling a manufacturing organisation to produce products that are better, cheaper and made faster than the competition. However, the wrong technology, or even the right technology poorly implemented, can be disastrous. Additive Manufacturing (AM) technologies have played an important role in product development (Rapid Prototyping) for many years, and we are beginning to see their use in production applications, albeit on a limited scale. This research proposes that the only similarity between using these technologies for prototyping and production is the process itself. Secondly, that there remains a significant gap in our knowledge of when and how to implement AM, and that this knowledge is key to increasing the adoption and diffusion of these technologies. This research project investigates the process of AM implementation over its lifecycle, identifying and developing an understanding of the factors influencing its success and failure. Beginning with a framework developed from the process technology implementation literature and existing AM implementation studies, exploratory case studies are used to test this framework and develop implementation roadmaps.  
 
Timestepping errors in weather and climate simulations  
Paul Williams (University of Reading)  
5 May 2011  Harrison LT04 Thursday 2pm  Applied Mathematics 
Comprehensive assessments of uncertainty in weather and climate prediction models should in principle consider contributions from the discretised numerical schemes, as well as from the parameterised physics and other sources. The numerical contributions are often assumed to be negligible, however. This talk reviews the evidence for uncertainty arising from timestepping schemes. Most contemporary weather and climate models still use the simple centreddifference (leapfrog) timestepping scheme, in concert with the RobertAsselin filter to stabilise the computational mode. This talk proposes a new alternative filter, known as the RAW filter, which substantially reduces the numerical errors and improves the formal accuracy. Examples are shown in which the new filter yields more skilful weather forecasts and reduces biases in climate models.  
 
Title: Pressure response analysis in head injury  
Christopher Pearce (Engineering, CEMPS, University of Exeter)  
7 Apr 2011  Harrison H170 (3D Visualisation Suite) Thursday 1pm  Advanced Technologies RI (Internal) 
Head injury is a significant cause of death and disability in society. Recent advances in Finite Element (FE) modelling techniques can provide insight and aid understanding of the trauma mechanisms of head injury. A new approach to generating biofidelic numerical models is presented based on a technique adapted from the marching cubes approach. This approach automates the generation of meshes based on 3D scan data and allows for a number of different structures (e.g. skull, scalp, brain) to be meshed simultaneously. The numerical models were used to validate an analytical model developed by one of the authors and good agreement was observed. Under certain impact conditions low mass impactors were found to produce large transient peaks of positive and negative pressure in the brain. A sensitivity study was conducted to investigate the robustness of this effect across a wide range of impact conditions. Numerical models of increased biofidelity were then analyzed and the transient pressure amplification behaviour for certain impact conditions was again observed; this provides confidence that the behaviour holds true as the model becomes more realistic. Beyond its significance in the area of head impact biomechanics, the study has demonstrated that numerical models generated from 3D medical data can be used effectively to simulate physical processes. This is particularly useful when considering the risks, difficulties and ethical issues involved when using cadavers.  
 
Calibrating computer simulators using ABC  
Richard Wilkinson (University of Nottingham)  
28 Mar 2011  Harrison 209 Monday 3pm  Applied Mathematics 
Computer simulators are now used in nearly all scientific disciplines. Comparing simulators with observations of reality (in order to estimate parameters, quantify errors etc) is major challenge for statistics. In this talk I'll introduce a relatively new class of methods that can be used to calibrate simulators called Approximate Bayesian Computation (ABC) algorithms. I'll illustrate these methods on a problem from evolutionary biology.  
 
Review of the Euler singularity problem (and our small contribution).  
Andrew Gilbert (with Walter Pauls, University of Bielefeld).  
23 Mar 2011  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
TBA  
*no seminar  no room available*  
21 Mar 2011  Harrison 170 Monday 2pm  Applied Mathematics 
 
Title: On the Use of OpenSource Software for Complex CFD Modeling: from Blood Damage in Cardiovascular Devices to Interaction of Wind Turbines with the Atmospheric Boundary Layer  
Professor Eric Paterson (Computational Mechanics Division, Applied Research Laboratory, The Pennsylvania State University)  
17 Mar 2011  Harrison 215 Thursday 2pm  Advanced Technologies RI 
Over the past 5 years, the computational fluid dynamics (CFD) community has witnessed the emergence of the first significant opensource software package (OpenFOAM) that rivals the capabilities of commercial software tools. Cost savings of "free" software is attractive to organizations which incur large software licensing fees, however, these cost savings are often offset by the need for resident expertise in molding the opensource tools to local needs. The real benefits of using opensource tools is the gain in local expertise and "ownership" (i.e., it is no longer a black box), and the access to source code and a flexible architecture, both of which are significant enablers for new and complexphysics modeling. The focus of this presentation will be on the use of OpenFOAM at Penn State University in modeling a number of complex fluid dynamics problems, including: blood damage in heartassist devices; conjugate mass transfer and canine olfaction; compressible multiphase flow associated with underwater explosions; fluidstructure interaction of flexible turbomachinery; adjointbased optimization for hydropower; and windturbines operating in a turbulent atmospheric boundary layer. An overview and key results for each problem will be presented, along with a discussion of how OpenFOAM enabled successful modeling of these complex problems.  
 
Chaotic mixing in a helixlike pipe with periodic variations in curvature and torsion  
Mitsuaki Funakoshi (Kyoto University)  
17 Mar 2011  Harrison 170 Thursday 2pm  Applied Mathematics 
Chaotic motion of fluid particles by a steady viscous flow in a helixlike circular pipe caused by an axial pressure gradient, and mixing efficiency of this flow are numerically examined. This pipe is wound around a circular or elliptic cylinder with a constant pitch so that the curvature kappa and torsion tau of centerline of this pipe vary continuously and periodically. If both kappa and tau are small and slowlyvarying, the crosssectional motion of fluid particles is expected to be approximately governed by the sum of Dean's flow and the flow of rigid rotation. From Poincare sections and the values of an index of the extent of mixing, it is found that there is an intermediate range of Reynolds number Re of flow within which chaotic regions in Poincare sections are large and mixing efficiency in a short time is high. Moreover, larger chaotic regions and higher mixing efficiency are observed for pipes wound around a circular cylinder of smaller radius, and for pipes wound around a thinner elliptic cylinder. These results can be explained by the variation in characteristic ratio 12 tau / (kappa Re) in one period.  
 
Unfolding of homoclinic and heteroclinic behaviour in a multiplysymmetric strut buckling problem.  
Dr Khurram Wadee  
16 Mar 2011  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
Localized buckling in infinitely long structures has been at the forefront of furthering our understanding of homoclinic solutions in a class of reversible fourthorder systems. At criticality, the system encounters a subcritical HamiltonianHopf bifurcation from which emanate homoclinic (localized) solutions. These are unstable in the physical sense but the presence of higher order nonlinearity can act to stabilize the solutions. When appropriate stabilization is present, the homoclinic solution transforms into a heteroclinic solution with the propogation of a front. Careful analysis of the boundary layer between the zero solution and constant finite amplitude solution is the key to understanding how this transformation occurs. These predictions are then tested against numerical solutions of the governing equations.  
 
Latent Force Models  
Prof. Neil Lawrence (Department of Computer Science, University of Sheffield)  
16 Mar 2011  Harrison 215 Wednesday 2pm  Computer Science 
Physics based approaches to data modeling involve constructing anaccurate mechanistic model of data, often based on differentialequations. Machine learning approaches are typically datadrivenperhaps through regularized function approximation.These two approaches to data modeling are often seen as polaropposites, but in reality they are two different ends to a spectrum ofapproaches we might take.In this talk we introduce latent force models. Latent force models area new approach to data representation that model data through unknownforcing functions that drive differential equation models. Bytreating the unknown forcing functions with Gaussian process priors wecan create probabilistic models that exhibit particular physicalcharacteristics of interest, for example, in dynamical systemsresonance and inertia. This allows us to perform a synthesis of thedata driven and physical modeling paradigms. We will show applications of these models in systems biology and (given time) modelling of human motion capture data.  
 
Differential Geometric MCMC Methods  
Prof. Mark Girolami (Department of Statistical Science, University College London)  
15 Mar 2011  Harrison 209 Tuesday 3pm  Computer Science 
In recent years a reliance on MCMC methods has been developing as the “last resort” to perform inference over increasingly sophisticated statistical models used to describe complex phenomena. This presents a major challenge as issues surrounding correct and efficient MCMCbased statistical inference over such models are of growing importance. This talk will argue that differential geometry provides the tools required to develop MCMC sampling methods suitable for challenging statistical models. By defining appropriate Riemannian metric tensors and corresponding LeviCivita manifold connections MCMC methods based on Langevin diffusions across the model manifold are developed. Furthermore proposal mechanisms which follow geodesic flows across the manifold will be presented. The optimality of these methods in terms of mixing time shall be discussed and the strengths (and weaknesses) of such methods will be experimentally assessed on a range of statistical models such as LogGaussian Cox Point Process models and Mixture Models. This talk is based on work that was presented as a Discussion Paper to the Royal Statistical Society and a dedicated website with Matlab codes is available at http://www.ucl.ac.uk/statistics/research/rmhmc  
 
Title: Memristive Devices and Applications  
Dr Themis Prodromakis (Imperial College)  
10 Mar 2011  Harrison H170 (3D Visualisation Suite) Thursday 2pm  Advanced Technologies RI 
As CMOS technology approaches the nanoscale floor, electron devices attain comparable dimensions to their constituting atoms, imposing significant challenges on the performance, reliability and eventually the manufacturability of analogue and digital circuits. Yet, in 1959 R. Feynman proposed that there is plenty of room at the bottom and he predicted that the operation of emerging devices would rely on the manipulation of just a few atoms; the memristor is nowadays considered as an exemplar device. Memristive devices are not something new; we have been experiencing similar dynamics well before Leon Chua established the theoretical grounds of the field. Yet, such behaviours were, until recently, attributed to random hysteretic effects, since the ionic mechanics were not fully appreciated. Nowadays though, we are able to reliably reproduce memristive elements and utilise their unique properties in novel applications. During this talk, I will present the stateoftheart developments in the field while it will be demonstrated how memristive dynamics could be exploited in practical applications, with particular emphasis in the areas of analogue IC design and neurobiology.  
 
Detecting the Interior Profile of Jupiter’s Differential Rotation by Gravity Science Techniques.  
Dali Kong  
9 Mar 2011  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
NASA’s JUNO Jupiter probe is going to be launched soon. One of its primary scientific goals is to determine the interior structure, and the deep atmosphere of Jupiter, by making detailed measurements of its complete gravity field from orbit tracking. The observations may help unveil the mechanism producing one of the most fascinating Jovian features, the persistent zonal jets and belts structure on Jupiter’s visible surface. In this work, for the first time, an up bound is given upon how much Jovian gravity field can be distorted, if a deep differential rotation model is assumed. The problem is discussed based on perturbed Maclaurin spheroid theory but is ready to be generalized to a more realistic physical state. It is suggested that the largest field expansion coefficient J_2 of Jupiter may be subject to a 10^{3} relative change owing to the current observed zonal jet speed.  
 
TBA  
TBA  
7 Mar 2011  Harrison 209 Monday 3pm  Applied Mathematics 
 
Title: Multiobjective Optimisation in Additive Layer Manufacturing processes  
Giovanni Strano (Engineering, CEMPS, University of Exeter)  
3 Mar 2011  Harrison H170 (3D Visualisation Suite) Thursday 1pm  Advanced Technologies RI (Internal) 
Selective Laser Sintering (SLS), as one of the most widely used additive manufacturing technologies, represents a valuable manufacturing process in the aerospace, automotive and medical industries. Due to the preheating requirement for the SLS of polymer materials, one of the main challenges is to reduce the energy required for the part building process and at the same time maintain the surface quality of the parts, represented by surface roughness, as this has aesthetic and functional importance for industrial applications. These objectives are competing criteria and are significantly influenced by the build orientation of the parts in the SLS process. This study investigates a computational methodology for the simultaneous minimization of surface roughness and energy consumption in the SLS process, to locate the optimal tradeoff set between these objectives, known as Pareto set; thus, it provides with a consistent decision support system for the identification of optimal build orientations for Selective Laser Sintering. The methodology and the mathematical approach presented are generally applicable to powder bed based ALM platforms such as Selective Laser Melting (SLM) and Electron Beam Melting (EBM). The multiobjective approach, in addition to the studied objectives, can be employed for the optimisation of more targets, for example by including the minimisation of anisotropy in mechanical proprieties of part produced by any ALM platforms.  
 
Metric Learning with Eigenvalue Optimization  
Dr. Yiming Ying (Department of Computer Science, University of Exeter)  
1 Mar 2011  Harrison 209 Tuesday 3pm  Computer Science (Internal) 
In this talk I will mainly present a novel eigenvalue optimization framework for learning a Mahalnobis metric from data. Within this context, we introduce a novel metric learning approach called DMLEigen which is shown to be equivalent to a wellknown eigenvalue optimization problem called minimizing the maximal eigenvalue of a symmetric matrix. Moreover, we show that similar ideas can be extended to large margin nearest classifiers (LMNN) and maximummargin matrix factorisation for collaborative filtering. This novel framework not only provides new insights into metric learning but also opens new avenues to the design of efficient metric learning algorithms. Indeed, firstorder algorithms scalable to large datasets are developed and their convergence analysis will be discussed in detail. At last we show the competitiveness of our methods by various experiments on benchmark datasets. In particular, we report an encouraging result on a challenging face verification dataset called Labeled Faces in the Wild (LFW).  
 
On the applied Mathematics of Ocean Waves  
Peter Janssen (ECMWF)  
28 Feb 2011  Harrison 170 Monday 2pm  Applied Mathematics 
For the (applied) Mathematician the subject of ocean waves, or to be more precise, surface gravity waves is an interesting problem because on the one hand it is a relatively simple and attractive while on the other hand the subject is very relevant for society. Nevertheless, due to its nonlinear character the problem has still not been solved, despite the fact that it received considerable attention for at least two centuries. Presently there is a renewed interest in the subject because of attempts to try to understand the generation of "freak" waves. After a brief historical account of the subject I will introduce the hamiltonian formulation of surface gravity waves. For weak nonlinearity there is a natural distinction between free and bound gravity waves. This distinction allows the introduction of a relatively simple evolution equation, which is called the Zakharov equation. From this evolution equation a number of interesting properties of weakly nonlinear water waves may be derived. In this talk I will concentrate on only one property, namely the instability of a uniform wave train which is an example of a fourwave interaction process. In fluid Mechanics this instability is called the BenjaminFeir instability. It turns out that this instability, because it is a fourwave interaction, is also found in other fields. Examples are nonlinear Optics and Plasma Physics. In its most simple form the BenjaminFeir Instability leads to the generation of envelope solitons which provides a possible explanation for the generation of "freak" waves. Because these extreme events are rare, forecasting of freak waves is difficult. Nevertheless, the probability of these extreme events can be estimated and at ECMWF probablistic forecasting of "freak" waves was introduced a number of years ago. This is the 32nd Taylor & Francis sponsored seminar  Taylor & Francis are publishers of the journal "Geophysical and Astrophysical Fluid Dynamics".  
 
Discrete Mereotopology in automated histological image analysis  
Dr. David A. Randell (Medical Imaging Research Group, College of Medical and Dental Sciences, University of Birmingham)  
22 Feb 2011  Harrison 209 Tuesday 3pm  Computer Science 
This crossdisciplinary talk covers the integration of qualitative spatial reasoning (QSR) with quantitative histological image processing methods using digitised images of stained tissue sections and other preparations examined under the microscope. The talk will show how the QSR spatial logic Discrete Mereotopology can be used to model and exploit topological properties of segmented images of cells and their parts and general tissue architecture. Relation sets and other mathematical structures extracted from the theory are factored out and used to complement and guide algorithmicbased segmentation methods. The net result is a change of emphasis away from classical pixelbased segmentation algorithms to one where the primary ontological primitives are regions and their spatial relationships each to the other. The work forms part of that done by the Medical Imaging Group with a longstanding interest in: image segmentation in histopathology, quantitative measures of tissue architecture and complex data characterisation and visualisation.  
 
**POSTPONED** Timestepping errors in weather and climate simulations  
**POSTPONED** Paul Williams (**POSTPONED** University of Reading)  
21 Feb 2011  Harrison 170 Monday 2pm  Applied Mathematics 
Comprehensive assessments of uncertainty in weather and climate prediction models should in principle consider contributions from the discretised numerical schemes, as well as from the parameterised physics and other sources. The numerical contributions are often assumed to be negligible, however. This talk reviews the evidence for uncertainty arising from timestepping schemes. Most contemporary weather and climate models still use the simple centreddifference (leapfrog) timestepping scheme, in concert with the RobertAsselin filter to stabilise the computational mode. This talk proposes a new alternative filter, known as the RAW filter, which substantially reduces the numerical errors and improves the formal accuracy. Examples are shown in which the new filter yields more skilful weather forecasts and reduces biases in climate models.  
 
Accelerating chaos control: how waiting can speed things up  
Chris Bick (Max Planck Institute for Dynamics and SelfOrganization, Goettingen)  
15 Feb 2011  Harrison 254 Tuesday 2pm  Applied Mathematics 
 
Huabing Yin  
Microengineering biointerfaces for sensing and cell response (University of Glasgow)  
14 Feb 2011  Harrison 170 Monday 2pm  Applied Mathematics 
In the body, a cell senses and responds to its surrounding microenvironment. Increasingly, it has been demonstrated that this behavior is associated with important processes like stem cell differentiation, cancer cell invasion and wound healing. However, the natural habitat of a cell, the extracellular matrix (ECM), consists of interconnected physical, chemical and biological cues. Understanding the influence of these arrangements on cell function will have a profound impact in developing biomaterials that induce desired cellular responses. However, it remains an ongoing challenge. In this context, we have been developing microenvironments in vitro with the aim to closely mimic the multiplex cues found in vivo. Our work combines microfabrication, microfluidics and new surface chemistry to create functional biointerfaces, where multiple cues (both biological and physical) are spatially arranged on a length scale of nano and micrometers. This interdisciplinary approach has enabled a flexible platform for a number of applications, ranging from high throughput drug screening for pharmaceutical development to the emerging fields of stem cell research. For example, discrete or gradient patterns of single or multiple biomolecules (e.g peptide and carbohydrates) have been reliably generated on a surface to investigate their collective roles in regulating cell migration, differentiation and elasticity (via AFM indentation). In this talk, I will discuss the rationales behind the design of these biointerfaces, their advantages and the challenges with our recent work in these areas.  
 
TBA  
TBA  
7 Feb 2011  Harrison 170 Monday 2pm  Applied Mathematics 
 
Title: On the mechanism of displacive phase transformations  
Professor Bob Pond (University of Exeter)  
3 Feb 2011  Harrison H170 (3D Visualisation Suite) Thursday 1pm  Advanced Technologies RI (Internal) 
Phase transformations are key processes in the manufacture and application of engineering materials. In displacive transformations, the transforming material undergoes a change of shape, primarily by shear. This feature underlies key properties such as the hardenability of steel and the toughening of ceramics. It is also responsible for the widely exploited properties of shapememory and superelastic alloys. It is important to develop a comprehensive understanding of the processes of nucleation and growth of a new phase. Recent research on growth mechanisms and the factors governing transformation kinetics will be outlined in this talk. The techniques employed are principally transmission electron microscopy and atomicscale computer simulation.  
 
TBA  
TBA  
31 Jan 2011  Harrison 170 Monday 2pm  Applied Mathematics 
 
Automating the Heuristic Design Process  
Dr. Matthew Hyde (ASAP Group, University of Nottingham)  
26 Jan 2011  Harrison 170 Wednesday 2pm  Computer Science 
The current state of the art in the development of search methodologies is focused around the design of bespoke systems, which are specifically tailored to a particular situation or organisation. Such bespoke systems are necessarily created by human experts, and so they are relatively expensive. Some of our research at Nottingham is concerned with how to build intelligent systems which are capable of automatically building new systems. In other words to automate some of the creative process, to make it less expensive by being less reliant on human expertise. In this talk, I will present some work we have recently published on the automatic design of heuristics for two dimensional stock cutting problems. The research shows that genetic programming can be used to evolve novel heuristics which are at least as good as human designed heuristics for this problem. Research into the automatic design of heuristics could represent a change in the role of the human expert, from designing a heuristic methodology, to designing a search space within which a good heuristic methodology is likely to exist. The computer then takes on the more tedious task of searching that space, while we can focus on the creative aspect of designing it.  
 
Implicit hydrodynamic simulations of stellar convection  
Maxime Viallet (Physics Dept, University of Exeter)  
24 Jan 2011  Harrison 170 Monday 2pm  Applied Mathematics 
 
Many Objective Optimisation of Engineering Problems  
Dr. Evan J. Hughes (Department of Informatics and Sensors, University of Cranfield)  
19 Jan 2011  Harrison 170 Wednesday 3pm  Computer Science 
Most real engineering problems are characterised by having many criteria that are to be optimised simultaneously. Unfortunately the criteria are often conflicting and so have to be considered as a manyobjective optimisation process in order to derive a tradeoff surface of the available optima solutions. Although a plethora of algorithms have been developed for optimising twoobjective problems, many of them do not work well as the number of objectives increase. The talk introduces some of the new algorithms that have been developed for investigating manyobjective problems and describes how the methods have been used to advance the design of airborne firecontrol and surveillance radars.  
 
Order vs. chaos when the space is discrete.  
Franco Vivaldi (Queen Mary)  
17 Jan 2011  Harrison 170 Monday 2pm  Applied Mathematics 
 
Title: Quality in Supply Chains  Good Relationships Needed for Successful Engineering Business  
Pinar Baban (Engineering, CEMPS, University of Exeter)  
13 Jan 2011  Harrison H170 (3D Visualisation Suite) Thursday 2pm  Advanced Technologies RI (Internal) 
This research focuses on improving the performance of supply chains with regard to quality. Recent examples from industry such as Toyota gas pedal failure and global banking crisis as an outcome of the lack of common rules over the national and international financial regulatory norms show that supply chains, operating in both manufacturing and service, are still experiencing problems. Supply chain structure along with relationship factors proposes a potential for a successful integration in a supply chain for which supply chain quality can be defined. As supply chain quality is considered as a relatively unexplored area, a contribution to the literature would be possible by developing a conceptual framework in which formulation, centralisation, communication and relationship factors are simultaneously adapted in constructing the conceptual model. Main purpose of the research is to transcend the quality concept of an organisation to the supply chain level with reference to this model. The case study method is used to test the conceptual model. Data collected is to be analysed in order to verify the model so that practical implications and guidelines for firms operating in various fields ranging from manufacturing to service sectors could be formulated.  
 
Accounting for the limitations of quantitative models  
Jonty Rougier (University of Bristol)  
10 Jan 2011  Harrison 171 Monday 2pm  Applied Mathematics 
There is a wide spectrum of modelling approaches for complex systems. However, in an area such as environmental science, even the most 'realistic' models tend to result in substantial system uncertainty. These realistic models are usually too unwieldy to be embedded within a statistical framework, necessary for performing the standard tasks of model criticism, model calibration, and system prediction. Instead, we consider whether it is possible to use much simpler 'phenomenological' models. The principles and practice are illustrated using a model for glacial cycles developed by Michel Crucifix as part of the ITOP project. The practice uses the very latest techniques from statistical computing, namely Particle Markov chain Monte Carlo (PMCMC).  
 
Passive scalar decay in chaotic flows with boundaries  
Fatma Zaggout  
14 Dec 2010  Harrison 101 Tuesday 9am  Applied Mathematics (Internal) 
We study the decay rate of a passive scalar in twodimensional chaotic flows, with a focus on the effect of boundary conditions for kinematically prescribed velocity fields with random or time periodic timedependence. The boundary conditions on the scalar and flow in a subdomain are imposed by restricting to a subclass invariant under certain symmetry transformations. At late times the decay of the variance of a passive scalar, for example temperature, is exponential in time with rate $\gamma$. For a variety of different cases scaling laws of the form $\gamma(\kappa) \simeq C \kappa^\alpha$ are obtained with exponents $\alpha$ that depend on the boundary conditions mentioned before.  
 
Dynamics of differentialdelay equations with single, multiple and timevarying lags  
Gabor Kiss (University of Bristol)  
13 Dec 2010  Harrison 170 Monday 2pm  Applied Mathematics 
We compare the stability properties of some families of delay differential equations with one delay to associated families of equations with distributed delays. With the aid of some examples, we indicate some differences between the nonlinear oscillations of equations with one and distributed delays. Furthermore, we report on the existence of pullback attractors of multiple delayed equations.  
 
Title: The impact and blast resistance of lightweight structures  
Professor Wesley Cantwell (Centre for Materials and Structures, University of Liverpool)  
9 Dec 2010  Harrison H170 (3D Visualisation Suite) Thursday 2pm  Advanced Technologies RI 
This talk will focus on current and recent research investigating the response of lightweight materials and structures to impact and blast loads. The presentation will initially outline a number of projects on topics such as high rate Mode III interlaminar fracture, scaling effects, smart materials based on shape memory alloys and embedded optical fibres and new lightweight core materials for sandwich structures. Attention will then focus on the impact and blast response of both thermoplasticmatrix compositemetal hybrid systems (fibre metal laminates) and lattice structures manufactured using the selective laser melting technique. Attempts are made to model the dynamic behaviour of the FMLs and lattice structures using finite element techniques.  
 
Dispersion of Pollution by Transitional Atmospheric Boundary Layers  
Alex Taylor  
7 Dec 2010  Harrison 101 Tuesday 9am  Applied Mathematics (Internal) 
We consider the dispersion of passive tracer particles within the atmospheric boundary layer through the development of two different methods, Lagrangian stochastic modelling and largeeddy simulation. Initially we focus on obtaining agreement with previous studies and observations for the case of a steady convective boundary layer, moving on to address the case of a typical evening 'decaying' convective boundary layer and investigating the role of residual convective turbulence on dispersion.  
 
To snake or not to snake in the planar SwiftHohenberg equation  
Daniele Avitabile (University of Surrey)  
6 Dec 2010  Harrison 170 Monday 2pm  Applied Mathematics 
Localised stationary structures play an important role in many biological, chemical and physical processes. Such structures have been observed in a variety of experiments ranging from verticallyvibrated granular materials, liquid crystals, binaryfluid convection, autocatalytic chemical reactions, electrochemical systems to nonlinear optical devices. We investigate the bifurcation structure of stationary localised patterns in a prototypical model, the two dimensional SwiftHohenberg equation, on an infinitely long cylinder and on the plane. On cylinders, we find localised roll, square and stripe patches that exhibit snaking and nonsnaking behaviour on the same bifurcation branch. Some of these patterns snake between four saddlenode limits: recent analytical results predict then the existence of a rich bifurcation structure to asymmetric solutions, and we trace out these branches and the PDE spectra along these branches. On the plane, we study the bifurcation structure of fully localised roll structures, which are often referred to as worms. We also show preliminary numerical results on oscillons, that is, timeperiodic spatiallylocalised structures.  
 
Title: Carbon Based Memories: Understanding the observed switching behaviour at the nanoscale  
Peiman Hosseini (Engineering, CEMPS, University of Exeter)  
2 Dec 2010  Harrison H170 (3D Visualisation Suite) Thursday 1pm  Advanced Technologies RI (Internal) 
The ever increasing demand for data storage capacity has pushed the current dominating technologies to their respective limits. Research groups around the world are investing enormous effort and resources to develop the next generation of memory devices that target 100 billion $ market currently shared between HD, DRAM and FLASH. Following the discovery of fullerenes Carbon continues to receive great scientific attention thanks to its extraordinary chemical and physical properties. Given the right environmental conditions carbon can exist as stable graphite or metastable Diamond, these allotropes have completely different electrical conductivity making them appealing for memory systems. The aim of our research project is to induce change in nanoscale regions of thin carbon films and to characterize and understand the nature of the observed switching effect that results.  
 
Various Formulations for Learning the Kernel and Structured Sparsity  
Prof. Massimilino Pontil (Department of Computer Science, UCL)  
1 Dec 2010  Harrison 170 Wednesday 2pm  Computer Science 
The problem of learning a Mercer kernel is of central importance in the context of kernelbased methods, such as support vector machines, regularized least squares and many more. In this talk, I will review an approach to learning the kernel, which consists in minimizing a convex objective function over a prescribed set of kernel matrices. I will establish some important properties of this problem and present a reformulation of it from a feature space perspective. A well studied example covered by this setting is multiple kernel learning, in which the set of kernels is the convex hull of a finite set of basic kernels. I will discuss extensions of this setting to more complex kernel families, which involve additional constraints and a continuous parametrization. Some of these examples are motivated by multitask learning and structured sparsity, which I will describe in some detail during the talk.  
 
Uncertainty in Climate Projections.  
Mat Collins  
30 Nov 2010  Harrison 101 Tuesday 9am  Applied Mathematics (Internal) 
We are not certain about how severe future climate change will be. Climate models that are used to make projections of the future are known to be inadequate at simulating past climate and climate change because of limitations in computing resources and because of limitations in our understanding of the climate system. Although models are constantly improved, inadequacies persist and policy makers are beginning to require quantitative information to plan for the future. This talk will discuss techniques for dealing with uncertainties using physical, mathematical and statistical approaches. A particular example will be future climate projections made for the UK under the UKCP09 project (http://ukcp09.defra.gov.uk/).  
 
Convergence of fastslow ODEs to stochastic differential equations  
Ian Melbourne (University of Surrey)  
29 Nov 2010  Harrison 254 Monday 10am  Applied Mathematics 
A project started recently with Andrew Stuart investigates the convergence of certain deterministic systems to a stochastic differential equation. For (presently oversimplified) fastslow systems, we prove, under very mild conditions on the fast variables (including the case where the fast equation is the Lorenz attractor), that the slowvariable solutions converge to solutions of a stochastic differential equation. A major difference between our approach and related projects is that we do not rely on decay of correlations for the fast variables (decay of correlations for flows is a notoriously difficult and poorly understood problem). Instead we use invariance principles (a generalisation of the central limit theorem giving convergence to Brownian motion) and large deviation estimates which have been derived for a very large class of systems in collaboration with Matthew Nicol.  
 
Adaptive Mesh Modelling of the Global Atmosphere  
Hilary Weller (University of Reading)  
29 Nov 2010  Harrison 170 Monday 2pm  Applied Mathematics 
The next generation of models for weather and climate prediction may look very different from the current, well optimised generation: Future models may use different grids which avoid the pole problem and use unstructured or adaptive meshes. During this talk I will demonstrate some advantages and disadvantages of a latlon grid, a cubed sphere and triangular and hexagonal icosahedral grids both with and without local refinement. I will then describe and demonstrate a mesh refinement criteria which anticipates mesh requirements many time steps into the future.  
 
Robustness of funnel control in the gap metric.  
Markus Mueller  
23 Nov 2010  Harrison 101 Tuesday 9am  Applied Mathematics (Internal) 
For minput, moutput, finitedimensional, linear systems satisfying the assumptions (i) minimum phase, (ii) relative degree one and (iii) positive highfrequency gain), the funnel controller achieves output regulation in the following sense: all states of the closedloop system are bounded and, most importantly, transient behaviour of the tracking error is ensured such that its evolution remains in a performance funnel with prespecified boundary. As opposed to classical adaptive highgain output feedback, system identification or internal model is not invoked and the gain is not monotone. Invoking the conceptual framework of the nonlinear gap metric we show that the funnel controller is robust in the following sense: the funnel controller copes with bounded input and output disturbances and, more importantly, it may even be applied to a system not satisfying any of the classical conditions (i)–(iii) as long as the initial conditions and the disturbances are “small” and the system is “close” (in terms of a “small” gap) to a system satisfying (i)–(iii).  
 
Scaling properties of the spectrum for DDEs with large delay  
Matthias Wolfrum (Weierstrass Institute for Applied Analysis and Stochastics, Berlin)  
22 Nov 2010  Harrison 170 Monday 2pm  Applied Mathematics 
Delaydifferential equations play an important role in many applied problems including e.g. economy, neuroscience, and optoelectronics. For the dynamics of semiconductor lasers with optical feedback or coupling in many cases the delay caused by the finite speed of light has to be considered as large compared to the internal time scales of the laser being in the range of picoseconds. For a laser with optical feedback the classical LangKobayashi model shows a large variety of dynamical behavior related to the large delay, including the coexistence of many periodic solutions with different stability properties, high dimensional chaos and other. Starting from these phenomena, we investigate typical phenomena in delaydifferential equations (DDEs) where the delay time tends to infinity. We show that the spectrum of linear delay differential equations with large delay splits into two different parts. One part, called the strong spectrum, converges to isolated points when the delay parameter tends to infinity. The other part, called the pseudocontinuous spectrum, accumulates near criticality and converges after rescaling to a set of spectral curves, called the asymptotic continuous spectrum. We show that the spectral curves and strong spectral points provide a complete description of the spectrum for sufficiently large delay and can be comparatively easily calculated by approximating expressions. The abstract results will be illustrated by by some examples.  
 
Zero dynamics and funnel control of linear differentialalgebraic systems  
Thomas Berger (Ilmenau University of Technology, Germany)  
17 Nov 2010  Harrison 101 Monday 2pm  Applied Mathematics 
We consider linear differentialalgebraic equations of the form E\dot{x}_(t) = Ax(t) + Bu(t) y(t) = Cx(t) ; (1) for E,A \in R^{n \times n}, B,C^{T} \in R^{n \times m} and regular matrix pencil sEA \in R[s]^{n \times n}, i.e. det(sEA) \in R[s]\{0}. Furthermore we assume that the transfer function G(s) = C(sEA)^{1}B has proper inverse, i.e. G^{1}(s) exists and lim _{s \rightarrow \infty} G^{1}(s) = D for some D \in R^{m \times m}. For this class of systems a so called `zero dynamics form' which is a simple ("almost" a normal) form of the DAE is derived; it is a pendant to the wellknown ByrnesIsidori form for ODE systems. The `zero dynamics form' is exploited to characterize the zero dynamics of (1) by (A,E,B)invariant subspaces; structural properties such as stable zero dynamics, minimum phase, and highgain stabilizability are also characterized. Finally, the zero dynamics form is the main mathematical tool to show that the `funnel controller', that is a timevarying proportional output error feedback u(t) = k(t)e(t), achieves for all DAE systems (1) with stable zero dynamics that the output signal y(\dot) tracks a reference signal y_{ref}(\dot) with respect to prespecified transient behaviour.  
 
Initialising Decadal Prediction in HadCM3 with RAPID Array Observations  
Leon Hermanson (University of Reading/Met Office)  
16 Nov 2010  Harrison 101 Tuesday 3pm  Applied Mathematics 
The RAPID array consists of several moorings at about 26°N in the Atlantic that measure temperature and salinity from which the meridional overturning circulation (MOC) and its components at this latitude can be determined. The main aim of the VALue Of the RAPID array (VALOR) project is to assess the value of the RAPID array observations for predictions of the Atlantic MOC and its impact on climate. In addition, the project will explore a range of issues concerning the design of a potentional MOC prediction system. One of the models used in this work is the Hadley Centre HadCM3 model. In this work we have investigated the issues that arise when trying to initialise the HadCM3 model with the RAPID observations. This has initially been investigated in an idealised setting where pseudoobservations from the same model are used to reconstruct a known transport. Leon is a Research Fellow at University of Reading, but is currently seconded to the Met Office, where he is working in the Decadal Climate Prediction group. He is visiting the College for the entire week 159 Nov to work with Tom Fricker and Chris Ferro, so will be available to talk to about any aspect of his seminar, or his wider work, during that time.  
 
Probabilistic transient envelope: Characterizing Disturbances and Perturbations.  
Iakovos Matsikis  
16 Nov 2010  Harrison 101 Tuesday 9am  Applied Mathematics (Internal) 
We study the transient effect of deterministic or stochastic distrubances on a system that is perturbed deterministically or stochastically by constructing a transient envelope. The envelope is constructed with intensive simulation and it allows us to calculate the initial structures that cause amplification and attenuation over all time steps of interest, the biggest and smallest values the system might assume and the probability that the output belongs in certain bounded intervals. For application we use population projection matrices.  
 
Finescale structure formation in Saturn's rings  
Henrik Latter (University of Cambridge)  
15 Nov 2010  Harrison 170 Monday 2pm  Applied Mathematics 
Recent radio and UV occultation experiments carried out by the Cassini spacecraft have revealed that swathes of Saturn's A and Bring support finescale axisymmetric patterns. This 'microstructure' is surprisingly regular, possessing wavelengths between 150 and 250 metres, and is probably driven by a pulsational instability of viscous origin. Using a simple hydrodynamical model, I show how this finescale quasiperiodic structure is related to nonlinear wave trains associated with the instability. I will also examine how variations and `defects' in the waves' phase and amplitude may relate to irregular features on largerscales. This is the 31st Taylor & Francis sponsored seminar  Taylor & Francis are publishers of the journal "Geophysical and Astrophysical Fluid Dynamics".  
 
Title: Proper Use of Unit Cells in Micromechanical Finite Element Analyses of Materials with Periodic Microstructures  
Professor Shuguang Li (Faculty of Engineering, University of Nottingham)  
11 Nov 2010  Harrison 170 (3D Visulisation Suite) Thursday 2pm  Advanced Technologies RI 
Unit cells have been increasingly employed in various analyses, in particular, for micromechanical analyses of composite materials where periodicities feature the microstructure, often in conjunction of the use of finite elements. The formulation of a unit cell could start as if it was a trivial exercise, at least as often perceived. However, it soon becomes overwhelming to such an extent that most attempts have gone either futile or incorrect, as is often observed in open literature, including research papers from reputable academic journals. Some typical examples of this kind will be cited to set the scene for the discussion. The lecture is intended to draw some clear guidelines for proper formulation of unit cells in a systematic manner, which rests firmly on the concept of symmetries and their physical properties. Significant implications of properly formulated unit cells on the preprocessing (meshing) and postprocessing (e.g. derivation of effective properties) will be discussed.  
 
Analysis, synthesis and applications of gene regulatory network models  
Prof. Yaochu Jin (Department of Computing, University of Surrey)  
10 Nov 2010  Harrison 107 Wednesday 2pm  Computer Science 
This talk starts with a brief introduction to computational models of gene regulatory networks (GRN), followed by a description of our recent results on analyzing and synthesizing gene regulatory motifs, particularly from the robustness and evolvability perspective. We show that in a feedforward Boolean network, the tradeoff between robustness and evolvability cannot be resolved. In contrast, how that this tradeoff can be resolved in an ODEbased GRN model for cellular growth based on a quantitative evolvability measure. In addition, we demonstrate that robust GRN motifs can emerge from in silico evolution without an explicit selection pressure on robustness. Our results also suggest that evolvability is evolvable without explicit selection.  
 
The climate and habitability of planets orbiting red dwarf stars  
Manoj Joshi (NCAS Climate, Reading)  
8 Nov 2010  Harrison 170 Monday 2pm  Applied Mathematics 
The concept of the habitable zone, or the region in which a planet can support liquid water at its surface, is almost ubiquitous in studies of "astrobiology", or the study of life in the universe. The habitable zone becomes especially interesting when considering red dwarf stars, or those stars with a mass between 0.1 and 0.5 times that of the Sun. On the one hand, red dwarfs are far more common than sunlike stars, and are thought to maintain their mean luminosity for much longer; on the other hand a red dwarf's habitable zone is so close to the star that phenomena such as tidal locking and stellar flares might be important in determining whether or not a planet can support an atmosphere (or even life). In this talk I'll review research on the habitable zone, especially with regard to red dwarf stars; work which shows that while the tidal locking of planets orbiting red dwarfs is not a barrier to habitability, stellar activity might be; and finally how all this is relevant to present and future planetfinding space missions.  
 
Title: FullereneLike WS2 Nanoparticles and Nanocomposites: Processing, Characterisation and Applications  
Dr Hong Chang (Engineering, CEMPS, University of Exeter)  
4 Nov 2010  Harrison H170 (3D Visualisation Suite) Thursday 1pm  Advanced Technologies RI (Internal) 
A fullerene is any molecule composed entirely of carbon, in the form of a hollow sphere, ellipsoid, or tube. Following the discovery of carbon fullerenes and nanotubes, closedcage noncarbon fullerenelike nanoparticles or nanotubes were discovered and they were given the name of inorganic fullerenelike materials (abbreviated as IFs). This research is focused on the processing and characterisation of WS2 IFs and their nanocomposites. The presentation will begin with a review on the extraordinary properties and potential applications of WS2 IFs, followed by the research motivation, periodic research progresses and plans for future work.  
 
Buoyant plumes: simple models and largeeddy simulation  
Ben Devenish (Met Office)  
3 Nov 2010  Harrison 106 Wednesday 2pm  Applied Mathematics 
NOTE  THIS IS THE SEMINAR POSTPONED FROM 27th OCTOBER. Examples of buoyant plumes abound in both natural and manmade situations: the recent eruption of Eyjafjallajokull in Iceland and the plume generated by the fire at the Buncefield oil depot in December 2005 are just two wellknown examples. The ability to predict the dispersion of any resulting hazardous material was demonstrated with dramatic effect earlier this year and provides a clear motivation for the study of buoyant plumes. Despite their obvious complexity, buoyant plumes have been successfully described by relatively simple models. In this talk I will review these models and then consider what further insight can be gained from largeeddy simulations. I will also present results on more complicated but realistic scenarios such as the effect on the plume of a crosswind.  
 
An Ontology of Information and Information Bearers.  
Dr. Antony Galton (Computer Science)  
3 Nov 2010  Harrison 170 Wednesday 2pm  Computer Science (Internal) 
In many areas, such as emergency management, coordinated action can be hampered by lack of suitable informatic support for integrating diverse types of information, in different formats, from a variety of sources, all of which may be relevant to the problem at hand. To create software that is able to handle such a diversity of information types in a unified framework it is necessary to understand what types of information there are, what forms they can take, and how they are related to each other and to other entities of concern. To this end, I am currently developing a formal ontology of information entities to serve as a reference point for subsequent system development activities. In this talk I will discuss some of the issues that I have had to address in developing the ontology.  
 
The role of global manifolds in the transition to chaos in the Lorenz system  
Bernd Krauskopf (University of Bristol)  
1 Nov 2010  Harrison 170 Monday 2pm  Applied Mathematics 
joint work with Hinke Osinga (University of Bristol) and Eusebius Doedel (Concordia University). The Lorenz system still fascinates many people because of the simplicity of the equations that generate such complicated dynamics on the famous butterfly attractor. This talk addresses the role of twodimensional stable manifolds of the origin and of saddle periodic orbits in organising the overall dynamics. These global objects need to be computed numerically with specialized algorithms. We present an approach that is based on the continuation of orbit segments, defined as solutions of suitable boundary value problems. In this way, we are able to study bifurcations of global manifolds as the Rayleigh parameter of the Lorenz system is changed. We show how the entire phase space of the Lorenz system is organised and how the manifolds change dramatically during the transition to chaotic dynamics. The delicate structure of global manifolds that we find also demonstrates the accuracy of the computations.  
 
***** SEMINAR POSTPONED TO 3rd NOVEMBER *****  
Ben Devenish (***** SEMINAR POSTPONED TO 3rd NOVEMBER *****)  
27 Oct 2010  Harrison 101 Wednesday 2pm  Applied Mathematics 
***** SEMINAR POSTPONED TO 3rd NOVEMBER *****  
 
Novel Machine Learning Methods for Data Integration  
Dr. Colin Campbell (Intelligent System Lab, University of Bristol)  
27 Oct 2010  Harrison 170 Wednesday 2pm  Computer Science 
Substantial quantities of data are being generated within the biomedical sciences and the successful integration of different types of data remains an important challenge. We begin the talk with an overview of our motivation for our investigations in this context. We begin by briefly reviewing work on the joint unsupervised modeling of several types of data believed functionally linked such as microRNA and gene expression array data from the same cancer patient. Next we consider supervised learning and outline several approaches to multikernel learning which can handle disparate types of input data. We conclude with a discussion of future avenues for investigation in this context.  
 
On Finite Element Methods for Fully Nonlinear Elliptic Equations of Second Order  
Klaus Boehmer (University of Marburg)  
25 Oct 2010  Harrison 170 Monday 2pm  Applied Mathematics 
For the first time, we present for the general case of fully nonlin ear elliptic differential equations of second order a nonstandard C1 finite element method (FEM). We consider, throughout the paper, two cases in parallel: For convex, bounded, polyhedral domains in Rn, or for C2 bounded domains in R2, we prove stability and convergence for the corresponding conforming or nonconforming C1 FEM, resp. The classical theory of discretization methods is applied to the differential operator or the combined differential and the boundary operator. The consistency error for satisfied or violated boundary conditions on polyhedral or curved domains has to be estimated. The stability has to be proved in an unusual way. This is the hard core of the paper. Essential tools are linearization, a compactness argument, the interplay between the weak and strong form of the linearized operator and a new regularity result for solutions of finite element equations. An essential basis for our proofs are Davydov’s results for C1 FEs on polyhedral domains in Rn or of local degree 5 for C2 domains in R2. Our proof for the second case in Rn, includes the first essentially as special case. The method applies to quasilinear elliptic problems not in divergence form as well. A discrete Newton methods converges locally quadratically, essentially independently of the actual grid size by the mesh independence principle.  
 
Rubberband Algorithms  A General Strategy for Efficient Solutions of Euclidean Shortest Path Problems  
Prof. Reinhard Klette (University of Auckland, New Zealand)  
20 Oct 2010  Harrison 170 Wednesday 2pm  Computer Science 
Algorithms for solving shortest path problems in 2D or 3D Euclidean space are typically either solvable in linear time, or of higher order time complexities, often even NPhard. Rubberband algorithms follow a general design strategy which is relatively simple to implement assuming a step set has been identified which contains the vertices of shortest paths, and is easily calculable itself. The talk informs about solutions to selected shortest path problems using rubberband algorithms.  
 
Flows on real networks  
David Arrowsmith (Queen Mary)  
18 Oct 2010  Harrison 170 Monday 2pm  Applied Mathematics 
 
Title: Mechanical Properties as a function of NanoArchitecture  
Dr Dean C. Sayle (Department of Engineering and Applied Science, Cranfield University)  
14 Oct 2010  Harrison H170 (3D Visualisation Suite) Thursday 2pm  Advanced Technologies RI 
If we build an arch not out of stone bricks, but using NanoBuilding Blocks will it have unprecedented load carrying capacity? Here, we formulate ‘Engineering Rules at the Nanoscale’ using HPC. Specifically, we use atomistic computer simulation to generate models of nanomaterials and calculate their mechanical properties. In particular, nanoparticle building blocks are positioned at crystallographic positions to facilitate a particular (nano)architecture and the mechanical strength calculated using molecular dynamics simulation.  
 
Kent's talk: A hyperheuristic approach to generating mutation operators with tailored distributions.
Richard's talk: A Bayesian Framework for Active Learning  
Kent McClymont and Richard Fredlund (Computer Science)  
13 Oct 2010  Harrison 107 Wednesday 2pm  Computer Science (Internal) 
Kent's talk: Discussion on a method for generating new probability distributions tailored to specific problem classes for use in optimisation mutation operators. A range of bespoke operators with varying behaviours are created by evolving multimodal Gaussian mixture model distributions. These automatically constructed operators are found to match the performance of a single tuned Gaussian distribution when compared using a (1+1) Evolution Strategy. In this study, the generated heuristics are shown to display a range of desirable characteristics for the DTLZ and WFG test problems; such as speed of convergence.
Richard's talk: We describe a Bayesian framework for active learning for nonseparable data, which incorporates a query density to explicitly model how new data is to be sampled. The model makes no assumption of independence between queried datapoints; rather it updates model parameters on the basis of both observations and how those observations were sampled. A "hypothetical" lookahead is employed to evaluate expected cost in the next timestep. We show the efficacy of this algorithm on the probabilistic highlow game which is a nonseparable generalisation of the separable highlow game introduced by Seung et al. (1993). Our results indicate that the active Bayes algorithm performs significantly better than passive learning even when the overlap region is wide, covering over 30% of the feature space.  
 
Evolution of magnetic helicity with the solar cycle: observations and dynamo theory  
Kirill Kuzanyan ((1) IZMIRAN, Russian Academy of Sciences, Moscow (2) National Astronomical Observatories of China, B)  
12 Oct 2010  Harrison 101 Tuesday 9am  Applied Mathematics 
We review the long term systematic observation of solar vector magnetic fields at several observatories in the USA, China and Japan. The data sample at Huairou Solar Observing station of Chinese Academy of Sciences (Beijing) cover the whole period 19882005 which is the longest available systematic dataset of threecomponent magnetic field in solar active regions over the two consecutive solar cycles 22 and 23. We can apply to this sample a selfconsistent averaging procedure which is the observational proxy to the averaging over the ensemble of turbulent pulsations. Thus we have obtained largescale coherent structures resembling the mean magnetic field. It obeys Hale’s polarity rule for sunspots and magnetic fields in quiet photosphere, in accord with other observational results. We also use the data sample to compute current helicity and twist. They are important observational proxies of magnetic helicity which is the invariant in MHD flows. These helical parameters demonstrate hemispheric sign rule: in the northern/southern hemispheres their signs are predominantly negative/positive. However, based on the data sample covering almost overall 22 year magnetic solar cycle we have established specific areas in latitude and time when they are regularly inverted, mainly in the beginning at the end of the sunspot butterfly wings. In solar dynamo models helicity can be used as an important nonlinear drive controlling growth of the solar cycle, and at the same time it is a proxy of the alphaeffect which is a measure of regeneration of the poloidal field from the toroidal one. We discuss possible implications of our observational findings in the light of the solar dynamo. 30th Taylor & Francis sponsored seminar  Taylor & Francis are publishers of the journal "Geophysical and Astrophysical Fluid Dynamics".  
 
Bifurcations in generalization of KuramotoSkaguchi model of coupled phase oscillators  
Oleksandr Burylko (National Academy of Sciences of Ukraine)  
11 Oct 2010  Harrison 170 Monday 2pm  Applied Mathematics 
We consider the extension of popular Kuramoto (KuramotoSakaguchi) model of globally coupled phase oscillators with the phase shift in coupling function that depends nonlinearly on the order parameter. This system was proposed by A.Pikovsky and M.Rosenblum (Phys. Rev. Lett. (2007), Physica D (2009). We discuss bifurcations of transition from full synchronization to desyncronization through different clustering states. We show that the typical way of this transition passes through different heteroclinic bifurcations. The obtained results are mostly based on the lemma about localization of equilibria that was proved. Also, we describe the multistability that occurs in the system.  
 
Crystal inspired beam networks with negative elastic properties  
Tom Hughes (Engineering, CEMPS, University of Exeter)  
7 Oct 2010  Harrison H170 (3D Visualisation Suite) Thursday 1pm  Advanced Technologies RI (Internal) 
An astonishing result was published in 1998: far from being the rare property it was then thought to be, negative Poisson's ratio behaviour in metals is actually quite common [1]. Of the 32 cubic metals investigated, around 69% were found to exhibit auxetic behaviour when strained in the [110] direction however, this paper only proposed inconclusive explanations and a limited mechanism. Since then, no study has revisited the issue, and no one has answered the really puzzling question, which is "why are one third of cubic metals NOT auxetic?". In this work we first study the elastic properties of cubic metals using atomistic modelling, and then of beam frameworks inspired by cubic metals using finite element analysis To determine the elastic constants for a range of 24 bodycentred and facecentred metallic crystals, we use twobody and manybody classical potentials. The elastic constants can then be used to calculate the Poisson's ratio of the crystals for a strain in any direction. The simpler twobody potentials obey the Cauchy relation, and consequently always predict a negative Poisson's ratio. ManyBody potentials, such as FinnisSinclair, are able to more accurately predict the elastic constants of the crystals and Poisson's ratios are generally found to be in agreement with experimental data published in the literature. The deformation mechanisms for both positive and negative Poisson's ratio in bodycentred and facecentred cubic structures are also determined. The bond network in cubic metals is also used as inspiration for truss structures composed of bending beams. By modelling the first, second and third nearest neighbour bonds in a cubic crystal as beams of varying stiffness, it has been possible to show (using the finite element method) how the Poisson's ratio of the structure changes from negative to positive according to the relative stiffness of the three classes of beams. This paradigm is then extended to investigate structures of lower symmetry, in a bid to find novel engineering structures with negative Poisson's ratio. [1] Baughman et al. Negative Poisson's ratios as a common feature of cubic metals. Nature 392, 362365 (1998)  
 
Librationally driven flow in triaxial ellipsoids.  
Keke Zhang  
5 Oct 2010  Harrison 101 Tuesday 9am  Applied Mathematics (Internal) 
 
The oscillations of rotating fluids and their applications to stars and planets  
Michel Rieutord (Laboratoire Astrophysique de Toulouse)  
4 Oct 2010  Harrison 170 Monday 2pm  Applied Mathematics 
Stars and planets are all rotating. Due to the conservation of angular momentum, this leads to specific oscillations known as inertial oscillations. These oscillations modify the lowfrequency oscillation spectrum of these bodies and introduce new phenomena which I shall try to describe in a simple manner. I'll present, for instance, some of the peculiarities of these oscillations (like singularities) and the role they play in the dynamics of tidally interacting bodies like stars harbouring a hot Jupiter. 29th Taylor & Francis sponsored seminar  Taylor & Francis are publishers of the journal "Geophysical and Astrophysical Fluid Dynamics".  
 
California Hottest and Coldest Days: Their Largescale Weather Patterns, Extreme Statistics, Downscaling, and Further Questions  
Richard Grotjahn (Atmospheric Science Program, Univ. of California, Davis, U.S.A.)  
19 Jul 2010  Harrison 170 Monday 2pm  Applied Mathematics 
Extreme hot days as defined for the California central valley (CV) have a characteristic large scale structure that affects much of the west coast of North America as well. Extreme cold air outbreaks affect much of the southwestern United States. The patterns for both types of extreme events (EEs) will be briefly summarized, including statistically highly significant regions far from California. Simple statistics (boostrap resampling and simple tail tests) for assigning significance to parts of the EE patterns in both cases will be summarized. The EE patterns for the hottest 1% of summer days have been compared to daily weather maps in a simple calculation of a daily anomaly 'HDA index' to hindcast (and forecast) hottest days in daily anomaly values. The 'HDA index' captures ~1/2 of the hottest 1% days from a 25 year period using a peaks over a threshold test to find the highest 1% of HDA index and CV observed temperature. Perhaps unexpectedly, the HDA index has high correlation with maximum temperatures on nearnormal and belownormal dates as well (overall correlation between daily maximum temperature at central valley stations and HDA index: 0.84). Remaining questions include how the large scale patterns develop dynamically and improved extreme statistics.  
 
Title: Infrared imaging in experimental mechanics  
Professor Janice Barton (School of Engineering Sciences, University of Southampton)  
1 Jul 2010  Harrison H170 (3D Vis Suite) Thursday 1pm  Advanced Technologies RI 
Infrared imaging is usually associated with fairly the crude temperature measurements made to assess the condition of structures and for thermal based nondestructive evaluations. Highly sensitive infrared detectors are now available that allow high spatial resolutions along with temperature resolutions of about 20 mK. If lockin processing is used the temperature resolution can be improved to 2 mK. A technique that takes advantage of the high spatial and temperature resolution of modern IR detectors is TSA (thermoelastic stress analysis). Here the infrared (IR) detector is used to 'measure' the small reversible temperature change associated with the thermoelastic effect from a component subjected to cyclic load. The detector output signal is related to the changes in the sum of the principal stresses on the surface of the material. Therefore the 'thermal image' provides fullfield data that is a function of the surfaces stresses. For orthotropic materials, such as laminated composite structures, the small temperature change is related to the changes in the stresses in the principal material directions on the surface of the material. The data is recorded and processed in a matter of seconds enabling practically realtime studies and hence providing clear benefit in damage evaluations. In the presentation the background theory underpinning the application of TSA is provided. The focus of the presentation is application of infrared imaging to polymer composites, sandwich structures and foam core materials. Examples of applications as well as some more fundamental physical issues will be presented.  
 
Demand Management  Good or Bad?  
David Evans (Water Resource Consultant)  
29 Jun 2010  Harrison 170 Tuesday 2pm  Informatics RI 
The UK’s population is predicted to rise by 20 million in coming decades, while the climate is expected to become wetter in winter and drier in summer. Much emphasis is therefore being put on demand management (or ‘water efficiency’)  but is this the right approach? Our climate is highly seasonal. In summer, evaporation exceeds rainfall and the incoming water resource is negative. But winter resources are large, and summer needs are met by storing winter surplus either naturally in the soil and as groundwater, or artificially in reservoirs. Wetter winters would increase that surplus (though perhaps offset by greater storminess). Groundwaters are fully committed, but water supply for the additional population can come from whatever is the best combination of demand management and surface water development. However, with climate change the predicted combination of less summer rain and higher evaporation spells summer desiccation. It is far from clear if there will be enough water to grow our food or to sustain our green environment. This could be a much bigger issue than water supply and the presentation explores it quantitatively. Fortunately water supply is nonconsumptive – it almost all comes back, either as effluent or as leakage, and can be reused, for example for irrigation. Even coastal effluents are water resources available to reclaim when needed. The more the water supply, the more the returns. Conversely, demand management reduces the amount of water that the water companies store in winter and return in summer. The presentation will show how the multiple benefits of water storage greatly exceed those of too much demand management. The future is alarming for our food and green environment. Reservoirs will help; demand management won’t.  
 
Flood frequency estimation in urban catchments  
Dr Thomas Kjeldsen (Centre for Ecology & Hydrology, Wallingford)  
22 Jun 2010  Harrison 170 Tuesday 2pm  Informatics RI 
The presentation will introduce the industrystandard for flood frequency estimation in the UK, the Flood Estimation Handbook (FEH), and review ongoing activities in quantifying the impact of urbanisation on catchment flood response and flood frequency relationships. Catchmentscale effects of urbanisation are shown to be complex, and the study will highlight future data requirements needed to improve modelling capabilities in catchments where urban areas interact with the terrestrial water cycle.  
 
Simple statistical methods for complex ecological dynamics  
Simon Wood (University of Bath)  
21 Jun 2010  Harrison 215 Monday 2pm  Applied Mathematics 
 
Mathematical analysis of circadian systems.  
Ozgur Akman  
15 Jun 2010  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
Circadian oscillations are universal, controlling 24hour rhythms of metabolism, physiology and behaviour in organisms ranging from humans to cyanobacteria. The regulatory gene networks underlying these oscillations have proved to be useful systems for quantifying the relationship between the structures of biochemical systems and their higher order properties. By constructing mathematical models of key circadian organisms and analysing the models using techniques derived from nonlinear dynamics, insights can be obtained into the reasons why circadian networks have considerably more complex architectures than the minimal negative feedback loop required for entrainable oscillations. Recent results obtained from modelling a range of circadian species suggest that one of the possible benefits of the high feedback loop complexity characteristic clock networks is the increased functional flexibility that such architectures confer. Moreover, the techniques developed to construct and analyse the models have potential applicability to a broader range of signalling pathways, particularly with respect to parameterfitting and sensitivity analysis.  
 
Mathematical modelling of the active process of hearing in insects and mammals  
Alan Champneys (University of Bristol)  
14 Jun 2010  Harrison 106 Monday 2pm  Applied Mathematics 
Hearing organs in mammals are remarkable in that a passive signal is electromechanically amplified over several orders of magnitude within the cochlear itself before any neural processing has taken place. In the insect world, the male mosquito also has a highly developed active hearing process, whose function is crucial to the mating process. It has recently been proposed, based on data from the bull frog, that the conceptual model of a Hopf bifurcation normal form captures all the features of the cochlear amplifier and that this might be a universal model across many species. The aim of this talk is to challenge this assertion and to show that there is no substitute for ab initio mathematical modelling that on the one hand attempts to capture the true physics and on the other hand is sufficiently simple to be amenable to qualitative as well as quantitative understanding. In particular I shall present recent work with Avitable and Homer based on the experiments in the lab of Robert in Bristol on a new mathematical model for the mosquito hearing organ. The organ is far more primitive than the mammalian cochlear and at bottom level can be described by a seesaw like lever arm that is attached to many threads that can provide mechanical stimulus in the form of a "twitch". The model is shown to capture the amplification of lowlevel sound, quenching of high input hysteresis and selfoscillation that is observed in live insects. I shall also present ongoing work with Szalai, Homer, O'Maoileidigh and JĂĽlicher together with experimental teams in Bristol and Keele on mathematical models for the outerhair cells that are thought to cause the active process within mammalian hearing. We show that this model displays a periodically forced cusp bifurcation, an unfolding of which is also able to show the characteristic 1/3growth law that a Hopf bifurcation normal form displays. We also show how the dominant features of this model produce a very different kind of simple model, this is able to match experimental data in showing regions of active amplification with different amplitudedependent exponents.  
 
Evolution 1  ID 0: One more case of biological complexity resolved.  
Orkun Soyer  
8 Jun 2010  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
The molecular basis of chemotaxis in the model organism Escherichia coli requires 7 signalling proteins, interacting in specific ways. The resulting dynamical system has nontrivial features including high sensitivity and precise adaptation. It remains unknown, how such a relatively complex system could have evolved and through which intermediary systems. This results in bacterial chemotaxis and the underlying signalling networks to be presented as an evolutionary puzzle. The lack of evolutionary understanding also limits our ability to extend the findings from E. coli to other species, which show remarkable differences to E. coli both in response dynamics and network structure. Using a mathematical approach we explore the potential evolutionary paths in chemotaxis. In particular, we reduce potential chemotaxis strategies to a simple formalism containing few key parameters that correspond to biological implementation of such strategies. We then compare the performance of such strategies under different parameter regimes. This yields a plausible evolutionary path from simple networks with straightforward dynamics to networks with adaptive dynamics. Interestingly, while the evolutionary transition can be driven only by selection for increased chemotaxis performance, the optimal performance can be achieved by different strategies under different parameter regimes (i.e. biological implementations).  
 
The use of acoustic methods for sewer network management  
Mr Richard Long (Richard Long Associates)  
8 Jun 2010  Harrison 170 Tuesday 2pm  Informatics RI 
The sewer system in the UK is ageing and is being put under increasing strain by climate change and ongoing development. To replace the systems would cost in excess of ?100billion and would be hugely disruptive, so careful management by the sewerage undertakers is vital. Yet they have only very limited information about the condition of their assets and how they are deteriorating over time. This need has been recognised by government and the companies themselves. Sewerage undertakers in the UK need more information, but existing CCTV technology is slow and it would be unaffordable to survey the whole sewer system on a regular basis this way. Anticipating a demand for new lowcost techniques, a team led by Bradford University has been collaborating to develop acoustic techniques to meet this need. By providing inexpensive, quick, accurate, digital output SewerBatt has the potential to allow the water industry and other industries with extensive drainage assets to meet the increasingly demanding requirements of government, regulators, customers and shareholders. The presentation will examine the need for new technology and describe the project undertaken. Examples of the output from the system will be provided and how it could be incorporated into sewerage management practice will be discussed.  
 
Dynamical Systems and Complex Networks: Are such Theories Useful for Neuroscience and Earth Sciences?  
Juergen Kurths (PIK, Potsdam)  
7 Jun 2010  Harrison 170 Monday 2pm  Applied Mathematics 
Complex networks were firstly studied by Leonhard Euler in 1736 when he solved the Königsberger Brückenproblem. Recent research has revealed a rich and complicated network topology in various model systems as well as in several fields of applications, such as transportation and social networks, or the WWW. It will be discussed whether this approach can lead to useful new insights into rather large complex systems or whether it is fashionable only to interpret various phenomena from this viewpoint and publish papers on that. A challenging task is to understand the implications of complex network structures on the functional organization of the brain activities. We investigate synchronization dynamics on the corticocortical network of the cat and find that the network displays clustered synchronization behaviour and the dynamical clusters coincide with the topological community structures observed in the anatomical network. Next we consider an inverse problem: Is there a backbonelike structure underlying the climate system? For this we reconstruct a global climate network from temperature data. Parameters of this network, as betweenness centrality, uncover relations to global circulation patterns in oceans and atmosphere. We especially study the role of hubs in the flows of energy and matter in the climate system. This new approach seems to be promising for understanding the dynamics of changing climate and its impacts.  
 
Statistical Attractors and the Convergence of Time Averages  
Ozkan Karabacak  
1 Jun 2010  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
There are various notions of attractor in the literature, including the ideas of measure (Milnor) attractors and statistical (Ilyashenko) attractors. We relate the notion of statistical attractor to that of the essential omegalimit set and prove some elementary results about these. In addition, we consider the convergence of time averages along trajectories. Ergodicity implies the convergence of time averages along almost all trajectories for all continuous observables. For nonergodic systems, time averages may not exist even for almost all trajectories. However, averages of some observables may converge; we characterize conditions on observables that ensure convergence of time averages even in nonergodic systems.  
 
Spectacle cycles and modular forms  
Dr Jens Funke (Durham university)  
27 May 2010  Harrison 203 Thursday 3pm  Pure Mathematics 
The classical Shintani lift is the adjoint of the Shimura correspondence. It realizes periods of even weight cusp forms as Fourier coefficients of a halfintegral modular form. In this talk we revisit the Shintani lift from a (co)homological perspective. In particular, we extend the lift to Eisenstein series and give a geometric interpretation of this extension. This is joint work with John Millson.  
 
Excitability in ramped systems: The compost bomb instability.  
Sebastian Wieczorek  
25 May 2010  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
About one year ago, Catherine Luke and Peter Cox reported (in one of our internal seminars) on the "combostbomb instability" which represents a potential tipping point in the response of the climate system to anthropogenic forcing. In this strongly nonlinear phenomenon, biochemical heat release destabilizes peatland above some critical rate of global warming, leading to a catastrophic release of soil carbon into the atmosphere. This talk explains the "compostbomb instability" as a novel type of excitability where a stable quiescent state exists for different fixed settings of a system's parameter but enormous excitable bursts appear when the parameter is increased gradually (ramped) from one setting to another. We show that an excitable system with a ramped parameter forms a singularly perturbed problem with at least two slow variables and focus on the case with locally folded critical manifold. Analysis of the desingularised flow identifies an excitability threshold as a canard trajectory through a folded singularity and leads to the analytical formula for the critical rate of global warming.  
 
Many Criteria Decision Making in Control and Systems Design  
Prof. Peter Fleming (University of Sheffield)  
25 May 2010  Harrison 170 Tuesday 2pm  Informatics RI 
Design problems arising in control and systems can often be conveniently formulated as multicriteria decisionmaking problems. However, these often comprise a relatively large number of criteria. Through close association with designers in industry a range of machine learning tools and associated techniques have been devised to address the special requirements of manycriteria decisionmaking. These include visualisation and analysis tools to aid the identification of features such as “hotspots” and noncompeting criteria, preference articulation techniques to assist in interrogating the search region of interest and methods to address the special computational demands (for example, convergence and diversity management) of these problems. Test problems and real design exercises will demonstrate these approaches.  
 
Normalized coprime representations for timevarying linear systems  
Markus Mueller  
18 May 2010  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
By considering the behaviour of stabilizable and detectable, linear timevarying statespace models over doublyinfinite continuous time, we establish the existence of socalled normalized coprime representations for the system graphs; that is, stable and stably left (resp. right) invertible, image (resp. kernel) representations that are normalized with respect to the inner product on L2(−oo,oo). The approach is constructive, involving the solution of timevarying differential Riccati equations with singlepoint boundary conditions at either +oo or −oo.  
 
CANCELLED Interfacial instabilities in a twolayer system with vertical electric current  
Sergei Molokov (University of Coventry)  
17 May 2010  cancelled cancelled cancelled cancelled  Applied Mathematics 
CANCELLED 28th Taylor & Francis sponsored seminar  Taylor & Francis are publishers of the journal "Geophysical and Astrophysical Fluid Dynamics". abstract TBA  
 
Title: Processing and applications of nanotubes and graphene  
Dr Ian Kinloch (School of Materials, University of Manchester)  
13 May 2010  Harrison 170 (3D Vis Suite) Thursday 2pm  Advanced Technologies RI 
 
Evidence for Rotational Parametric Instability in Earth's Core from Analysing Relative Paleointensity Data  
Keith Aldridge (York University, Canada)  
11 May 2010  Harrison 170 Tuesday 12noon  Applied Mathematics 
29th Taylor & Francis sponsored seminar  Taylor & Francis are publishers of the journal "Geophysical and Astrophysical Fluid Dynamics" Evidence for Rotational Parametric Instability in Earth's Core from Analysing Relative Paleointensity Data Abstract We have developed an algorithm to search records of relative paleointensity for evidence of a parametric instability in Earth's core. Under the assumption that the spectrum of magnetic field intensity is a proxy for that of fluid velocity, the presence in Earth's core of a parametric instability will be seen in records of the magnetic field intensity. As long as the strain rate produced by either precessional or tidal forces exceeds the dissipation rate, a parametric instability will grow and subsequently decay repeatedly as observed in laboratory experiments. In the event that the externally imposed strain rate is close to the dissipation rate, a balance will result in what we call a steady state. Our algorithm has searched records of relative paleointensity from sedimentary cores from the past 2 million years. We smooth the data and set a threshold of significant change in the field which is segmented into intervals of growth, decay or steady state. According to our model of parametric instability, adjacent decays and growths recovered by our algorithm can be combined to give the magnitude of the external strain rate. Application of this algorithm to the SINT2000 data reveals distinct maxima that correspond to all the reversals of the field in the interval studied. Thus our model for parametric instability in Earth's core is consistent with the occurrence of magnetic field reversals at times when the external straining is largest.  
 
What can convection teach us about the nature of turbulence?  
Fritz Busse (University of Bayreuth)  
11 May 2010  Harrison 170 Tuesday 11am  Applied Mathematics 
27th Taylor & Francis sponsored seminar  Taylor & Francis are publishers of the journal "Geophysical and Astrophysical Fluid Dynamics". abstract: TBA  
 
InfoGap Theory for Strategic Planning Under Severe Uncertainty: Applications to Pollution Control Policy  
Prof. Yakov BenHaim (Technion  Israel Institute of Technology)  
11 May 2010  Harrison LT04 Tuesday 2pm  Informatics RI 
Infogap theory is a method for analysis, planning, decision and design under uncertainty. The future may di®er from the past, so our models may err in ways we cannot know. Our data may lack evidence about surprises: catastrophes or windfalls. Our scientiŻc and technical understanding may be incomplete. These are infogaps: incomplete understanding of the system being managed. Infogap theory provides decisionsupport tools for modelling and managing severe uncertainty. After outlining the infogap methodology, we explore applications to public policy for pollution control. Given uncertainty in the marginal costs and beneŻts of pollution emission, is it better to impose a tax on pollution or to establish legal limits to pollution? Given uncertainty in the costs of abatement, how should a public regulator allocate auditing and enforcement resources?  
 
Selfconsistent nonlinear MHD  
David Hughes (University of Leeds)  
10 May 2010  Harrison 170 Monday 2pm  Applied Mathematics 
26th Taylor & Francis sponsored seminar  Taylor & Francis are publishers of the journal "Geophysical and Astrophysical Fluid Dynamics". The majority of astrophysical dynamo modelling is performed using mean field MHD, an elegant theory of MHD turbulence in which smallscale interactions are captured by various transport coefficients, most notably the alphaeffect. Here I shall extend the standard mean field approach from a kinematic one  treating the instability of a magnetic field to a purely hydrodynamic basic state  so as to consider fully MHD basic states (with both flow and field). It is then vital to treat the momentum and induction equations on the same footing. This leads to a description of any resulting instability in terms of four tensors, two familiar and two new.  
 
Industrial Experiences and Applications of Artificial Intelligence (AI) in RealTime Strategy Computer Games  
Ingimar Gudmundsson (Creative Assembly)  
7 May 2010  Harrison 170 Friday 1pm  Informatics RI 
TBA  
 
CANCELLED  
Fares Al Essa  
6 May 2010  Harrison 170 (3D Vis Suite) Thursday 1pm  Advanced Technologies RI (Internal) 
CANCELLED  
 
Control Engineering Approaches to Systems Biology Research  
Declan Bates (University of Exeter)  
4 May 2010  Harrison 170 Monday 4pm  Applied Mathematics 
 
Constraints on the relaxation of magnetic fields.  
Antonia WilmotSmith (University of Dundee)  
4 May 2010  Harrison 170 Tuesday 2pm  Applied Mathematics 
23rd Taylor & Francis sponsored seminar  Taylor & Francis are publishers of the journal "Geophysical and Astrophysical Fluid Dynamics" full abstract: TBA  
 
Decision making under risk: the optimization of storm sewer network design  
Sun Si'Ao (University of Exeter)  
4 May 2010  Harrison 215 Tuesday 2pm  Informatics RI 
It is widely recognised that flood risk needs to be taken into account when designing a storm sewer network. Due to the stochastic character of the flood risk, comparisons between candidate networks are not straightforward. This study aims to explore the decision making in flood risk based storm sewer network design. It is viewed as an optimisation problem with the decision criterion determined by a subject judgement of the decision maker. Several decision criteria are introduced and applied to select an optimal design after a multiobjective optimisation. Different decisions are made according to different criteria as a result of different concerns represented by the criteria. Moreover, the problem can be formed as a singleobjective optimisation if the decision criterion is provided a priori. The design using a singleobjective optimisation is also studied, with the flood risk being evaluated under design storms or via sampling.  
 
Deciphering the Swineflu pandemics of 1918 and 2009  
Richard Goldstein ((NIMR, Mill Hill))  
30 Apr 2010  Harrison 170 (visualisation suite) Friday 2pm  Applied Mathematics 
The devastating ‘Spanish flu’ of 1918 killed an estimated 50 million people worldwide, ranking it as the deadliest pandemic in recorded human history. It is generally believed that the virus transferred from birds directly to humans shortly before the start of the pandemic, subsequently jumping from humans to swine. By modelling how the viral sequences changes in human, avian, and swine hosts, we find it likely that the Spanish flu of 1918, like the current 2009 pandemic, was a 'swineorigin' influenza virus. Now that we are faced with a new pandemic, can we understand how influenza is able to change hosts? Again by modelling the evolutionary process, we can identify locations that seem to be under different selective constraints in humans and avian hosts, identifying changes that may have facilitated the establishment of the 2009 swineorigin flu in humans.  
 
Hertfordshire Surface Water Management Plan  
Mr Nathan Muggeridge (Mouchel)  
13 Apr 2010  Harrison 170 Tuesday 2pm  Informatics RI 
Defra awarded Ł9.7 million in October 2009 to allow 77 Councils to develop Surface Water Management Plans (SWMPs). One of these councils was Hertfordshire County Council and this presentation will provide an insight to the Strategy developed for the SWMP, tasks already completed and what is planned to be delivered. Presentation will cover risk, pluvial modelling, data collection and communication plan.  
 
Rules and Tools for Directed Evolution  
Florian Hollfelder (University of Cambridge)  
9 Apr 2010  Harrison 170 Friday 2pm  Applied Mathematics 
I will address approaches leading up to directed evolution of functional proteins. First the observation of catalytic promiscuity is used to define functional relationships in enzyme superfamilies as a basis for phylogentic relationships for catalysis. Promiscuous activities could be remnants from the evolutionary ancestor that has been gene duplicated and adapted to fullfill a new function. Alternatively the observation of promiscuity could indicate that an enzyme is ‘pregnant’ with another activity, i.e. has the potential to be mutated or evolved into a new catalyst Specifically we demonstrate this principle with observations of strong promiscuous activities with rate accelerations between 109 and 1016 in a class of hydrolytic enzymes that share an unusual formylglycine active site nucleophile. Promiscuity in these enzymes is not limited to a single activity, but allows the same active site to catalyse up to six activities efficiently in addition to its native activity.. Evolution experiments should ideally analysed by highthroughput approaches, but require the development of special technologies. The quantitative assessment of large numbers of experiments is possible in waterinoil emulsion droplets that act as discrete picolitre reactors. These droplets, originally introduced by Dan Tawfik and Andrew Griffiths, are so small that highthroughput experiments on the order of > 108 become possible. Recent experiments to this end  in vitro expression, cellbased assays and continuous PCR reactions – will be discussed. See: http://www.bio.cam.ac.uk/~fhlab/index.html  
 
A Taxonomy of Agility Strategies in UK Companies  
Rundong Wang (Engineering, CEMPS, University of Exeter)  
1 Apr 2010  Harrison 170 (3D Vis Suite) Thursday 1pm  Advanced Technologies RI (Internal) 
In the past decade, significant changes have taken place in manufacturing industry. The changes are characterized by the increased intensity of global outsourcing and global marketing, the rising energy and material costs and problems associated with the quality and security of the supply networks. Under this circumstance, firms have been forced to adjust their strategic manufacturing emphases and seek more effective strategies to survive from the dynamic and rapidly changing marketplace. Agility, that aims to provide firms with competitive capabilities to prosper from dynamic and continuous changes in the business environment, has been widely accepted as a prevailing strategy. Whilst most previous work has considered agility as a holistic concept, this study applies a taxonomical approach to identify if there are clear patterns in companies' needs for agility and in their emphases of agility capabilities. Furthermore, the most significant differences between agility strategies with respect to supply chain design and management practices are examined. In the presentation, the initial identification of existing patterns of agility strategies will be described. Typical cases will be briefly depicted with explanations of strategies and practices they adopted.  
 
Validation of mesospheric analyses  
David Long  
1 Apr 2010  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
The Met office produce analyses of the middle atmosphere on a daily basis. The project is concerned with validating these analyses against observational satellite data, namely profiles obtained from the EOS MLS and SABER experiments. Systematic baises in the dataset will be presented and concluesions drawn. Particular attention will be made to the operational gravity wave paramterisation scheme used at the Met Office and it's contribution to the accurate representation of the middle atmospheric circulation and temperature fields. The design of experiments with the aim of reducing the described systematic baises will be presented, with particular attention to the impact of including turbulent heating (due to gravity wave dissipation) in the operational parameterisation scheme.  
 
1D, 2D and 3D modelling of urban flooding  
Prof. Slobodan Djordjevic (University of Exeter)  
30 Mar 2010  Harrison 170 Tuesday 2pm  Informatics RI 
Within the dual drainage framework, flooding can be modelled either as flow in a network of 1D (onedimensional) open channels and ponds, or as a 2D flow with depthaveraged velocities, or as a 3D computational domain. Each of these approaches has its advantages and drawbacks, thus there is no single “best” choice of the dimensionality of surface flow. In addition, every model – be it 1D, 2D or 3D – involves specific problems related to: spatial resolution and generation of computational mesh, treatment of buildings and terrain features, subsurface/surface interactions, how the rainfall variability and surface runoff are introduced, possibilities for model calibration and how the uncertainties in model parameters are handled, communication of results etc. Therefore we can only talk about an adequate approach because it very much depends on the extent of the area, quality of available data, purpose and type of the analysis i.e. the required number of offline or realtime runs and other factors. The talk will address these issues through experiences from several ongoing urban flooding projects and by outlining some unresolved research questions and practical problems.  
 
Flux Rope Instabilities in Coronal Mass Ejections  
Bernhard Kliem (Potsdam)  
29 Mar 2010  Harrison 170 Monday 2pm  Applied Mathematics 
25th Taylor & Francis sponsored seminar  Taylor & Francis are publishers of the journal "Geophysical and Astrophysical Fluid Dynamics" Images of erupting prominences typically suggest the magnetic structure of a single linetied flux rope. Many prominence eruptions and coronal mass ejections (CMEs) begin with an approximately exponential rise, suggesting an instability. I will present numerical simulations of two relevant flux rope instabilities, the wellknown helical kink instability and the torus instability, using the forcefree linetied flux rope equilibrium by Titov and Demoulin as initial condition. The properties of these instabilities indicate which parameters of the initial configuration control whether the eruption stays confined or becomes ejective, evolves into a fast or a slow CME, shows strong or weak writhing. Exponential as well as powerlaw rise profiles can be modelled. Supporting quantitative comparison of the simulations with several well observed eruptions will be included.  
 
Averaging, passages through resonances, and captures into resonance in dynamics of charged particles  
Anatoly Neishtadt (Loughborough University)  
26 Mar 2010  Harrison 170 (visualisation suite) Friday 3pm  Applied Mathematics 
A study of motion of charged particles in the field of an electromagnetic or electrostatic wave propagating in plasma in the presence of a uniform stationary background magnetic field is a classical problem in plasma physics. Under different relations between parameters of this problem completely different dynamical phenomena take place. In this talk I am planning to describe phenomena of capture into resonance and scattering on resonance that occur in the case of slow high frequency waves and a weak background magnetic field. Capture into resonance may lead to unlimited particle acceleration along the front of the wave (so called surfatron acceleration).  
 
Extracting materials mechanical constitutive parameters from fullfield deformation measurements: the Virtual Fields Method  
Professor Fabrice Pierron (Laboratoire de Mécanique et Procédés de Fabrication)  
25 Mar 2010  Harrison 170 (3D Vis Suite) Thursday 1pm  Advanced Technologies RI 
The fast development and diffusion of fullfield deformation measurement techniques (such as digital image correlation, speckle interferometry etc.) has opened new prospects in the identification of the mechanical behaviour of materials. The research group led by Professor Fabrice Pierron has been active in this area for more than 15 years. In particular, an original identification method dedicated to fullfield measurements has been in the centre of most of the developments in the group. This technique is called the Virtual Fields Method (VFM, www.camfit.fr). The presentation will provide an overview of a vast range of applications of this methodology (static, vibrations, high strain rate) on different types of materials (composites, damaged materials, metals, welds, polymers, wood, foams etc...) to enhance the capabilities of the VFM and provide tracks for the future.  
 
Population Modelling of Montastraea annularis  
Heather Burgess  
25 Mar 2010  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
We are studying the reefbuilding coral Montastraea annularis. Previously we have modelled a population of coral patches using Population Projection Matrices. This involves the discretization of size. This discretization is restrictive because there is not enough data to accurately assign transition rates between some of these discretized size classes. Therefore we are now aiming to build an Integral Projection Model for this population which assumes continuous size classes. Some initial results are presented together with a comparison to our PPM approach.  
 
Applying real options and evolutionary optimisation methods to evaluate flood risk intervention strategies  
Ms Michelle Woodward (University of Exeter / HR Wallingford)  
23 Mar 2010  Harrison 170 Tuesday 2pm  Informatics RI 
A framework has been developed to analyse optimum flood risk intervention strategies. Real Options Analysis is recognised as an appropriate technique for valuing flexibility in investment decisions and is now promoted by the treasury as being appropriate for flood and coastal erosion risk management. In particular, the ability of Real Options Analysis to assist in developing climate change adaptation strategies is well recognised. Moreover, the application of Real Options combined with evolutionary optimisation methods, and in particular multiobjective optimisation, provides the ability to generate long term flood risk intervention strategies. A computational framework will be described which assesses the most appropriate set of interventions to make in a flood system and the opportune time to make these interventions, given the future uncertainties. This framework captures the concepts of real options and employs an optimised decision framework to evaluate potential flood risk management opportunities across a range of future climate change and socio economic scenarios.  
 
Geomagnetic reversals from low order dynamo models  
Graham Sarson (Newcastle University)  
22 Mar 2010  Harrison 170 Monday 2pm  Applied Mathematics 
24th Taylor & Francis sponsored seminar  Taylor & Francis are publishers of the journal "Geophysical and Astrophysical Fluid Dynamics" TBA  
 
CANCELLED  
Ozgur Akman  
18 Mar 2010  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
TBA  
Professor Frances Kirwan (University Oxford)  
18 Mar 2010  Harrison 106 Thursday 3pm  Pure Mathematics 
 
RainfallRunoff Simulation and Groundwater Recharge in Arid Regions  
Prof. Moshen Sherif (College of Engineering, UAE University)  
17 Mar 2010  Harrison 203 Wednesday 3pm  Informatics RI 
In arid and semiarid regions, rainfall events are limited and random. Extreme events are more frequent and, hence, detention and retention dams are usually built across the main wadis to intercept surface water runoff and recharge the groundwater systems. In this presentation, the focus is devoted to the simulation of surface water runoff and groundwater recharge due to water storage in the lakes of dams. HECHMS model is used to simulate the surface water runoff and water storage in the lakes of three main dams due to rainfall events in the northern area of the United Arab Emirates. Within the calibration process of HECHMS, the simulated water flow and storage in the dams were compared with the observed data for several storm events. Using the calibrated model, a family of rainfallrunoff/storage curves was developed based on the duration and intensity of rainfall events. These curves can be used for prediction of surface water runoff in the three wadis and water storage in the dams in response to different rainfall events. The groundwater recharge was simulated using MODFLOW. The model was calibrated and verified using different data sets and the results of groundwater levels were found to be in good agreement with the observed data. The model was also used to assess the increase of groundwater recharge due to the construction of dams. Significant amounts of the infiltrated water are retained in the unsaturated zone.  
 
A SimulationOptimisation Model to Study the Control of Saltwater Intrusion into Coastal aquifers  
Mr Hany F. AbdElhamid (University oif Exeter)  
16 Mar 2010  Harrison 170 Tuesday 2pm  Informatics RI 
Seawater intrusion is one of the most serious environmental problems in many coastal regions all over the world. It is one of the processes that degrade waterquality by raising salinity to levels exceeding acceptable drinking water standards. Mixing a small quantity of seawater with groundwater makes it unsuitable for use and can result in abandonment of aquifers. Therefore, seawater intrusion should be prevented or at least controlled to protect groundwater resources. This work presents development and application of a simulationoptimization model to control seawater intrusion in coastal aquifers using different management models. The model is based on the integration of a genetic algorithm optimization technique and a coupled transient densitydependent finite element model, which has been developed for simulation of seawater intrusion. The management scenarios considered include abstraction of brackish water, recharge of fresh water and combination of abstraction and recharge. The objectives of these management scenarios include minimizing the total costs for construction and operation, minimizing salt concentrations in the aquifer and determining the optimal depth, location and abstraction/recharge rates for the wells. Also, a new methodology is presented to control seawater intrusion in coastal aquifers. In the proposed methodology ADR (abstraction, desalination and recharge), seawater intrusion is controlled by abstracting brackish water, desalinating it using small scale reverse osmosis plant and recharging to the aquifer. The developed model is applied to a number of case studies. The efficiencies of three different scenarios are examined and compared. The results show that all the three scenarios could be effective in controlling sea intrusion but using ADR methodology, results in the lowest cost and salt concentration in aquifers and maximum movement of the transition zone towards the sea. The application of ADR methodology appears to be more efficient and more practical, since it is a costeffective method to control seawater intrusion in coastal aquifers. The developed model is an effective tool to control seawater intrusion in coastal aquifers and can be applied in areas where there is a risk of seawater intrusion. Finally, the developed simulation model is applied to study the effects of likely climate change and sea level rise on saltwater intrusion in coastal aquifers.  
 
HighFrequency SelfExcited Oscillations in 3D Collapsible Tube Flows  
Robert Whittaker (University of Oxford)  
15 Mar 2010  Harrison 170 Monday 2pm  Applied Mathematics 
Experiments show that steady flow along an elasticwalled tube can become unstable to largeamplitude oscillations involving both the tube wall and the fluid. We consider a 'Starling resistor' setup  a finite length elastic tube attached to rigid end sections, through which an axial flow is driven by either a steady flux at the downstream end or a steady pressure drop between the ends. I shall describe a theoretical analysis of smallamplitude highfrequency longwavelength oscillations. We first consider the fluid mechanics (prescribed oscillations) and then the solid mechanics (to derive an appropriate tube law) in isolation. The two strands of work are then combined to investigate the full fluidstructure interaction problem for selfexcited oscillations. We determine the form of the normal modes and obtain expressions for the growth rate and frequency of the oscillations. The predictions from our modelling show good agreement with numerical simulations performed using the oomphlib C++ library.  
 
Title: The Role of Particle Cavitation in the Toughening of Rubbermodified Epoxy Adhesives  
Professor Felicity Guild (Department of Mechanical Engineering, Imperial College London)  
11 Mar 2010  Harrison 170 (3D Vis Suite) Thursday 2pm  Advanced Technologies RI 
Many investigations into the source of toughness in rubber toughened adhesives have associated enhanced toughness with the process of rubber particle cavitation. Our model for rubber particle cavitation has now been established using an energy balance approach. This model used a combination of finite element simulations and experimental results. Predictions for rubber particle cavitation in both uniaxial loading conditions and the triaxial loading conditions ahead of a crack and the dependence on particle size will be presented and compared with experimental results. The energy contributions arising from the different energy sources can be evaluated. These predictions for particle cavitation allow the role of this process in the overall toughness of these materials to be assessed.  
 
Dynamics of microscale swimmers  
Andrew Gilbert (with Feodor Ogrin, Peter Petrov and Peter Winlove)  
11 Mar 2010  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
The problem of swimming on small scales, for example microorganisms, has a long and rich history. On such scales fluid may be thought of as very viscous (i.e. low Reynolds number) and one has to imagine swimming in treacle. It turns out that motions that are not timereversible need to be adopted to have persistent motion in one direction, the socalled 'scallop theorem'. Such swimmers need to break the symmetry, and biological organisms have evolved a variety of ways of achieving this. With interest now in micromachines and microscale processing of chemical and biological materials  the idea of the labonachip  there is interest in developing tiny scale pumps, valves, gels, and machines that can swim, perhaps to deliver a drug very precisely. Recently a microscale swimming device has been developed here in Physics by the Biomedical Physics Group, consisting of elastically coupled magnetic beads whose motion is driven by an external magnetic field. The seminar will discuss the mathematical modelling of such swimmers, regimes, parameters and mechanisms.  
 
irreducible $\Qp$representations of compact $p$adic analytic groups  
Dr Konstantin Ardakov (Nottingham university)  
11 Mar 2010  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Molecular Programming  
Luca Cardelli (Microsoft Research)  
10 Mar 2010  Harrison 215 Wednesday 2pm  Applied Mathematics 
Nucleic acids (DNA/RNA) encode information digitally, and are currently the only truly 'userprogrammable' entities at the molecular scale. They can be used to manufacture nanoscale structures, produce physical forces, act as sensors and actuators, and do computation in between. Eventually we will be able to interface then with biological machinery to detect and cure diseases at the cellular level under program control. The technology to create and manipulate them has existed for many years, but the imagination necessary to exploit them has been evolving slowly. Recently, some very simple computational schemes have been developed that are autonomous (run on their own once started) and involve only short (easily synthesizable) DNA strands with no other complex molecules. We need programming abstractions and tools that are suitable for molecular programming. Lowlevel molecular design is required to produce molecules that interact in the desired controllable ways. On that basis one can then design various kinds of 'logic gates' and 'computational architectures', which is where much of the imagination is currently needed. Then one needs programming languages both at the level of gate implementation (Andrew Phillips at Microsoft Research Cambridge has built a strandlevel DNA language and simulator), and at the level of circuit implementation (I will describe a Strand Algebra for implementing e.g. automata and Petri nets). Since DNA computation is massively concurrent, some tricky and yet familiar issues arise: the need to formally verify gate designs to avoid subtle deadlocks and race conditions, and the need to design highlevel languages that exploit concurrency and stochasticity.  
 
Community Resilience to Extreme Weather (CREW)  
Dr Albert Chen (University of Exeter)  
9 Mar 2010  Harrison 170 Tuesday 2pm  Informatics RI 
'Community Resilience to Extreme Weather' (CREW) is an EPSRCfunded research project, established to develop a set of tools for improving the capacity for resilience of local communities to the impacts of future extreme weather events. CREW focuses on understanding the probability of current and future extreme weather events and their likely socioeconomic impacts. Initiatives, such as the Stern Review, provide highlevel socioeconomic impacts but do not provide the subregional or local estimates pertinent at the community and individual scale. Therefore, the CREW consortium is investigating impacts at the local level (on householders, SMEs and local policy/decision makers). The research is also investigating the opportunities and limitations for local communities' adaptive capacity. CREW, using five South East London boroughs as case studies, is considering the decision making processes across communities including impediments and drivers of change. A webbased portal will provide a facility for presenting probable extreme weather events for a range of scenarios, and for presenting and evaluating coping mechanisms. Dr Slobodan Djordjevic and Dr Albert Chen at the CWS are involving with the Programme Package SWERVE (Severe Weather Events Risk and Vulnerability Estimators) of CREW for urban pluvial flood modelling. Albert Chen is going to introduce the CREW project and explain the details of modelling that accounts for the impact of future climate scenarios.  
 
Microchaos in switched control systems with digital sampling  
Piotr Kowalczyk (University of Manchester)  
8 Mar 2010  Harrison 170 Monday 2pm  Applied Mathematics 
TBA  
 
Giant Magnetoresistive and Multiferroic Thin Film Development Using a New Sputtering Technique  
Denh Tran (College of Engineering, Mathematics and Physical Sciences, University of Exeter)  
4 Mar 2010  Harrison 170 (3D Vis Suite) Thursday 1pm  Advanced Technologies RI (Internal) 
A new sputter deposition technique will be described. This technology, developed at Plasma Quest Ltd., is designed for high rate sputtering and uniform erosion of the target. This gives the name of the technique 'High Target Utilsation Sputtering' (HiTUS). Other key advantages of this technology will be highlighted. This seminar will also review the use of HiTUS for Giant Magnetoresistive thin films and the interesting new area of multiferroics.  
 
Stability Analysis of Three Linearly Coupled Laser Oscillators  
Nicholas Blackbeard  
4 Mar 2010  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
Coupled nonlinear oscillators exhibit rich and complex dynamics. Semiconductor lasers are particularly interesting and technologically relevant examples of nonlinear oscillators that feature an intrinsic amplitudephase coupling, quantified by the alphaparameter. This characteristic nonlinearity causes different dynamics that can be utilised for a wide variety of applications. Many of these require the use of laser arrays  where the desired behaviour ranges from a high power coherent radiation to that of robust chaos. We study a system of three lasers with nearest neighbour coupling as a first step towards understanding the complexity of larger arrays.  
 
Padic interpolation of automorphic forms  
Dr David Loeffler (University Warwick)  
4 Mar 2010  Harrison 106 Thursday 3pm  Pure Mathematics 
Coleman’s work on overconvergent padic modular forms shows that finite slope modular eigenforms can be interpolated padically, forming rigidanalytic families of eigenforms parametrised by their weights. This has been generalised by Emerton to cohomological automor phic representations of a wide range of reductive groups, where the local factor at p is principal series. I shall give an exposition of Emerton’s construction, and of recent joint work with Richard Hill and myself in which we have extended this to certain nonprincipalseries cases  
 
Neptune: RiskBased Decision Support for Water Distribution System Incident Management  
Mr Josef Bicik and Dr Mark Morley (University of Exeter)  
2 Mar 2010  Harrison 170 Tuesday 2pm  Informatics RI 
Project Neptune aims to develop an integrated, riskbased Decision Support System (DSS) to facilitate tactical (near realtime) and strategic decision making. This system should inform network operators and permit the rapid investigation, evaluation rectification of network failure events. In so doing, the Neptune DSS seeks to reduce the impact on customers, assist water companies in meeting regulatory requirements and to minimize the environmental and economic impact of incidents. This talk describes some of the work undertaken within the Centre for Water Systems on developing the riskbased methodologies and software components that make up the Neptune DSS. It concludes with a live demonstration of the Decision Support System on a number of case studies.  
 
Double Diffusive Magnetic Buoyancy Instability  
Lara Silvers (City University)  
1 Mar 2010  Harrison 170 Monday 2pm  Applied Mathematics 
The generation of magnetic field by velocity shear and the field’s subsequent evolution are of great importance to an understanding of the operation of the solar dynamo. While the current dynamo paradigm contains many complex interacting components, an integral part of all current largescale solar dynamo models is the creation of strong toroidal magnetic structures in the tachocline. Strong toroidal magnetic field is thought to be induced by the stretching action of the differential rotation on any background poloidal field. Subsequently, magnetic buoyancy instabilities of the generated field are invoked as the mechanism for the creation of distinct magnetic structures and their subsequent rise toward eventual emergence at the solar surface as active regions. In this talk I will focus on double diffusive magnetic buoyancy instabilities. I will discuss the criterion for this form of the instability to exist and show the first images from numerical simulations of this instability. This is the 22nd Taylor & Francis sponsored seminar  Taylor & Francis are publishers of the journal "Geophysical and Astrophysical Fluid Dynamics"  
 
For Whom the Bell Tolls The mute (silent) bell in Cologne cathedral as a dynamical system  
Tassilo Kuepper (University of Cologne)  
25 Feb 2010  Harrison 170 (vis suite) Thursday 2pm  Applied Mathematics 
The “Kaiserglocke” in the cathedral of Cologne is known as a spectacular example of a bell withstanding to ring since the clapper remained in the center of the bell, hence showing synchronous oscillations with the bell. Based on a mathematical model describing the motion of clapper and bell as two connected pendula Veltmann has shown that such synchronous oscillation may exist if only 4 characteristic parameters (“length” and mass of clapper and bell) satisfy a specific relation, which turned out to hold in the case of the “Kaiserglocke”. To prove, though, that under such constellation it is never possible for a bell to ring requires more advanced mathematical tools which had not yet been developed a 100 years ago. In this talk we will supplement Veltmann's argument with regard to stability considerations. The system of clapper and bell can serve as a nice illustration for modern mathematical investigations. Since Veltmann has only be interested to derive reasons for nonringing of bells, he only needed to consider motions without contact between clapper and bell. True ringing relies on that contact. Mathematically that requires an extension from the classical system of differential equations used by Veltmann by “impacts”. This leads to the class of nonsmooth dynamical systems, an area of present research. Our analysis shows how the interaction between bell and clapper influences the motion; for example we also show how various forms of ringing may result from a change of the coupling between clapper and bell.  
 
Optimisation on emergency scheduling of the raw water supply system in Zhuhai  
Qi Wang (Tsinghua University, China)  
23 Feb 2010  Harrison 170 Tuesday 2pm  Informatics RI 
For a water supply system near river estuary, the time length of taking river water is affected by the saline tide period. Therefore, in order to increase the security and reliability of the water supply system, it is necessary to make reasonable scheduling, which aims to ensure reservoirs volume within the system to meet the water demand during the saline intrusion period. In this research, a mathematical model on the water supply system with multisource near the estuary was established. A genetic algorithm was conducted to calculate the water level control lines of reservoirs, in which both the power consumption and system security were considered in the objective function. Compared with historical operating data, it shows that an optimal hydrograph obtained using the proposed method can significantly improve the security of water supply system and reduce the operation energy cost.  
 
padic Lfunctions of modular forms at supersingular primes  
Dr Antonio Lei (Cambridge university)  
22 Feb 2010  Harrison 171 Monday 2pm  Pure Mathematics 
 
The Theory of Configuration of Rapidly Rotating Giant Planets  
DaLi Kong  
18 Feb 2010  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
The classical homogeneous Maclaurin ellipsoid model for rapidly rotating planets is extended to a more realistic twolayer configuration by making use of a minimized energy principle combined with the hydrostatic free surface condition. By adopting oblate spheroidal coordinates, a universal semianalytical method is derived. The details about coordinate system, spheroidal harmonics, physical principles and special numerical integration techniques are intensively investigated.  
 
On volumes of arithmetic hyperbolic norbifolds.  
Dr Mikhail Belolipetsky (Durham University)  
15 Feb 2010  Harrison 106 Monday 2pm  Pure Mathematics 
The main topic of my talk is the search for the minimal volume quotients of the hyperbolic nspace. In dimension 2 the problem was solved by Siegel who also asked about the general case. Since then a considerable progress has been made for the socalled arithmetic quotients and the only case which was still open is when the dimension n is odd and >3. After a brief introduction I will focus on the solution to this problem which we obtained in a recent joint work with Vincent Emery.  
 
Recurrence and extreme behaviour in dynamical systems  
Mark Holland  
11 Feb 2010  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
We explore the statistical properties of chaotic dynamical systems, including case studies of the Lorenz and Henon attractors. We examine questions such as the long term distribution of typical solution trajectories and how frequently they visit a prescribed region of the space. We also discuss the issue of asymptotic (in)dependence: how long do we have to wait until the system settles down to some equilibrium and does this equilibrium dependent on the initial conditions?  
 
Weiestrass Points and Automorphisms of Curves  
Dr Kay Magaard (University of Birmingham)  
11 Feb 2010  Harrison 106 Thursday 3pm  Pure Mathematics 
Let $X$ be a compact connected Riemann surface of genus $g \geq 2$. A point of $p \in X$ is Weierstrass if there exists a nonconstant meromorphic function on $X$ that has a pole of order $\leq g$ at $p$ and is holomorphic on $X \setminus p$. A lemma of Sch\"oneberg asserts that if an automorphism $\alpha$ of $X$ fixes five or more points of $X$, then every one of them is a Weierstrass point. In the talk we will discuss the impact of Sch\"oneberg's lemma has on the structure of the automorphism group of $X$.  
 
Nonresidually finite extension of arithmetic groups.  
Dr Richard Hill (University College London)  
8 Feb 2010  Harrison 106 Monday 2pm  Pure Mathematics 
Let Gamma be an arithmetic group with the congruence subgroup property, and with an associated Shimura variety. A theorem of Deligne states that there is a central extension of Gamma by a cyclic group which is not residually finite. This result was used by Toledo to give examples of complex projective varieties for which the topological fundamental group does not embed in the algebraic fundamental group. In the talk I'll generalize Deligne's result to the case that Gamma has no associated Shimura variety, so for example my result holds for congruence subgroups of SL(n,Z) with n at least 3.  
 
A study of scanning probe phase change memory  
Dr Lei Wang  
4 Feb 2010  Harrison 170 (3D Vis Suite) Thursday 1pm  Advanced Technologies RI (Internal) 
Data storage roadmaps are looking towards density targets of around 1Tbit/in2 by 2010 and to 10Tbit/in2 and beyond thereafter. It is well known that conventional storage devices are challenged by some formidable barriers (the superparamagnetic limit for magnetic storage disks, the diffraction limit for optical storage disks, and device scaling limits in flash storage) as they strive to reach ultrahigh storage densities. It is hence timely for new, emerging memory technologies to enter the storage field. One possible new technology is scanning probebased phase change memories, due to their potentially ultrahighcapacity, nonvolatility, lowpower consumption, lowcost, and writeonce/rewritable capability. Therefore, various research groups worldwide have been putting their efforts in to developing scanning probe phase change memories technologies experimentally. In this circumstance, theoretical models are also required in order to understand the physical processes involved, and thus to help spur further experimental developments. Thus, this presenation looks at a theoretical framework and associated computational model for write, read, and erase processes in electrical probe storage on phase change materials (Ge2Sb2Te5).  
 
Condensation and metastability in stochastic particle systems  
Stefan Grosskinsky (University of Warwick)  
1 Feb 2010  Harrison 170 Monday 2pm  Applied Mathematics 
The zerorange process is a recently well studied stochastic particle system that exhibits a condensation transition. When the total density exceeds a critical value, a finite fraction of all particles condenses on a single lattice site, which can be characterized mathematically by the equivalence of ensembles via convergence in specific relative entropy. Although the transition is continuous, finite systems exhibit interesting metastable behaviour and phase coexistence. We establish a law of large numbers for the excess mass fraction in the maximum, which turns out to jump from 0 to a positive value at the critical point. The metastable states can be characterized heuristically as fixed points of a simple effective dynamical system.  
 
Congruences in noncommutative Iwasawa theory  
Dr Mahesh Kakde (University College London)  
28 Jan 2010  Harrison 106 Thursday 3pm  Pure Mathematics 
 
The confidence to build  Some thoughts on engineering software  
Prof. Bill Harvey  
26 Jan 2010  Harrison 170 Tuesday 2pm  Informatics RI 
Engineering software began about 1950 with some of the earliest available digital computers. It became possible to analyse complex structures. Since then, the poawer of computers has grown at an almost frightening rate. Endless bells and whistles have been added to analytical software. In recent years ther have been attempts to couple CAD programs to analysis and call the package design. But engineering design is not about deciding on a geometry then asking the computer where the forces go. Real design is about deciding where you want the forces to flow and then arranging the geometry to make that happen. The same thing is true in CFD but that is not where I work. It is long past time that we realised and released the power of computers to help with design insteead of merely providing analytical results. That will involve fundamental changes in our vision of what we want to do. Bill's work is chiefly in structural assessment and in this field, surprisingly, the problem is greater. When designing a new building, if the analysis says this bit is too weak, a stroke of a pen (or mouse) is enough to make it stronger. If the structure is already there we often need to know where the forces might really go rather than where they could go if they need to. The seminar will cover some of the issues described above in the light of the sort of exploratory analysis Bill uses for his assessment work.  
 
Integrated Water Management – Experience from Australia and GHD’s Innovative IWM Toolkit  
Mr Mike Jones (Head of Water, UK, GHD)  
19 Jan 2010  Harrison 170 Tuesday 2pm  Informatics RI 
Integrated Water Management (IWM) is a strategy that draws together all facets of the water cycle including water supply, sewage and stormwater management to achieve beneficial social, environmental and economic outcomes. While the application of IWM principles to the UK water industry is in its infancy, a wide range of IWM strategies have been used successfully in communities throughout Australia. We will present an overview of IWM in Australia. A number of case studies will be discussed that demonstrate the range of IWM strategies being developed in Australia along with some lessons learnt from the Australian experience. GHD’s IWM Toolkit will also be presented. The IWM Toolkit is an innovative water balance modelling software tool that simulates complex integrated water servicing scenarios to assist water system planners in identifying the preferred water servicing strategy from a range of options.  
 
Amplified stochastic oscillations  
Alan McKane (University of Manchester)  
18 Jan 2010  Harrison 170 Monday 2pm  Applied Mathematics 
I discuss a systematic approach to the modelling of various biological systems which starts from individualbased models, and then goes on to derive from these the corresponding deterministic equations (which are valid when the size of the system is large) and the leading order stochastic correction to them. The individualbased models are formulated as master equations, which allows use to be made of wellestablished methods from the theory of these equations to analyse their behaviours. In many cases large and welldefined stochastic cycles arise, even though the corresponding deterministic equations predict the system will approach a fixed point. Application of these ideas to predatorprey dynamics, epidemiology, cellular systems and autocatalytic reactions, amongst others, will be discussed.  
 
On Optimisation of Internal MicroArchitectures Using Finite Element Modelling  
David Raymont  
7 Jan 2010  Harrison 170 (3D Vis Suite) Thursday 1pm  Advanced Technologies RI (Internal) 
Internal microarchitectures have many uses ranging from lightweight support structures to bone substitutes, or scaffolds as well as aiding boneimplant integration. Designing such structures using traditional CAD software is nontrivial. This presentation focuses on the generation of porous internal microarchitectures principally for use in medical applications, but also extended to internal structures for CAD components. An imagebased approach is developed using triply periodic levelset functions to define unit cell topology. Methods for generating both functionally graded and large inhomogeneous microarchitectures will be presented. When addressing the issue of optimisation the limiting factor for such structures is often the finite element analysis (FEA) required for a fitness function. The complexity of these structures demands fine meshing, resulting in computationally expensive simulations. Combined with the need to evaluate the structure's performance hundreds or possibly thousands of times, the optimisation problem soon becomes intractable. To overcome this a homogenisationlike technique has been developed allowing approximate FEA models to be produced. Methods for optimising the generated microarchitectures will be discussed.  
 
Generalized stochastic resonance models for abrupt climate changes  
Istvan Daruka (Eotvos University, Budapest)  
14 Dec 2009  Harrison 170 (3D vis suite) Monday 9.30am  Applied Mathematics 
The glacialinterglacial changes observed in Paleoclimatic temperature data of the middle to late Pleistocene epochs are analyzed in terms of two generalized stochastic resonance models including memory effects. The simple models account for the asymmetric, sawtooth shaped temperature oscillations occurring both at Milankovitch (100kyr) and millennial time scales.  
 
RUAM: ReadytoUse Additive Layer Manufacture  
Dr Jorn Mehnen (Manufacturing Department, Cranfield University, Cranfield, Bedfordshire MK43 0AL, United Kingdom)  
10 Dec 2009  Harrison 170 (3D Vis Suite) Thursday 2pm  Advanced Technologies RI 
RUAM (ReadytoUse Additive Layer Manufacturing) is an innovative concept for building readytouse large metal parts. Additive Layer Manufacturing parts are built in a layerbylayer fashion using advanced arc welding processes. The RUAM machine is a hybrid concept that integrates welding and finishing in one single machine. The deposition process is controlled by a robot that follows a tool path that is directly created from CAD drawings. The robot paths are determined by design rules that take the complex behaviour of the arc welding process into account. FEM is used to predict temperature and stress distributions to minimise part distortions. The design for RUAM has to take many aspects into account which depend on e.g. the actual geometry and manufacturability of the parts. Best welding parameters as well as best welding techniques (e.g. CMT (Cold metal transfer) and Interpulse welding, high deposition rates) have been investigated for building efficiently readytouse RUAM parts. The first prototype of an integrated machine has been introduced. The RUAM machine is designed for building large structures in steel, aluminium and titanium.  
 
Longterm behavior of linear, stochastic, discrete time systems: Asymptotic amplification and attenuation in covariance  
Iakovos Matsikis  
10 Dec 2009  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
Lyapunov exponents are the tool widely used in studying the longterm dynamics of systems under the influence of randomness. They do not, however, take into account the effect of initial conditions and in general are difficult to compute. In this talk we will employ second mean analysis and ideas from linear algebra and will present the new notions of asymptotic amplification and attenuation in covariance. These new mathematical tools are depended on initial conditions, are easily computed and together with the second mean exponent they provide a framework of study for linear stochastic systems. Specifically they can be used in the construction of envelopes that capture the system's dynamics and make visible its asymptotic properties. We will finally apply our results to a population dynamics model.  
 
On the existence of quasipattern solutions of the SwiftHohenberg equation.  
Alastair Rucklidge ( University of Leeds)  
9 Dec 2009  Harrison HAR170 Wednesday 10am  Applied Mathematics 
 
Coupled water environmental model and system dynamics (SYDWEM) of integrated populationeconomywaterriver system in a rapidly urbanising catchment  
Dr HuaPeng Qin (University of Exeter)  
8 Dec 2009  Harrison 170 Tuesday 2pm  Informatics RI 
The rapidly urbanizing catchments in developing countries are usually faced with water quantity shortage and quality deterioration because water infrastructure development lags behind the demand of rapid population and economic growth. Although the existing environmental models can individually describe socioeconomic, water infrastructure and natural water systems, they cannot effectively capture the interactions among them. Taking rapidly urbanizing Shenzhen river catchment in China as an example, we developed a system dynamic based approach (SYDWEM) to couple water environmental models of populationeconomic, water infrastructure and river system in the catchment. The approach was verified to have the ability to simulate relationship between social, economic, water resource and effluent discharge issues as well as pollutant behaviour in the river. The approach was further applied to predict GDP and population growth, water balance and water quality variation in the catchment scale under proposed socioeconomic policies (e.g. industrial structure regulation, water conservation) and engineering measures (e.g. wastewater treatment and reuse). By comparing the effects and sensitivities of proposed polices and measures, integrated management strategy was proposed to harmonize the socioeconomy and ecoenvironment development in the catchment. The results indicated that SYDWEM provides a flexible decision making tool for integrated water management in urbanizing catchments.  
 
Assimilating data into ocean models  
Chris Jones (University of Warwick)  
7 Dec 2009  Harrison 170 Monday 2pm  Applied Mathematics 
Abstract: The technologyenabled increase in data acquisition is well matched by that coming from computational modeling. The subject of Data Assimilation (DA) addresses the issue of making optimal use of both sides of this equation. Bayes’ Theorem provides a framework for DA, but this is only the beginning of what is interesting mathematically. I have come at this subject from the perspective of Lagrangian DA, which aims at assimilating data from ocean instruments that "go with the flow". I will argue that Lagrangian DA is both exciting and promising exactly because the Lagrangian flow can be very complicated (highly nonlinear, chaotic etc) even though the fluid flow field may be tame. I will suggest that this leads to a guiding principle for DA as a whole.  
 
Additive Layer Manufacturing of Aluminium Aerospace Components  
Peter Jerrard  
3 Dec 2009  Harrison 170 (3D Vis Suite) Thursday 1pm  Advanced Technologies RI (Internal) 
Additive Layer Manufacturing (ALM) has now been around for 25 years and can be considered a process that has a place aside more conventional manufacturing methods. Due to some of the advantages that ALM offers many sectors, including the aerospace industry, have vested interest. Unfortunately, like other processes, ALM is far from perfect and is still considered a ‘novel’ process by many. This is due to such issues as limited material choice and mechanical properties, which can be poor when compared to other manufacturing techniques. In particular, the aerospace industry has particular interest in aluminium alloys, the current material of choice for aircraft. One ALM technology, Selective Laser Melting (SLM), allows the processing of a select range of metals. It is only in the last year or so that a few aluminium alloys have become officially available to SLM, which has drawn the attention of the aerospace industry. These alloys are conventional alloys that lend themselves to the SLM process. However, the processing nature of SLM may mean that conventional aluminium alloys may not be the best choice for producing parts. Instead, it may be that new or unconventional alloys may have to be tried. This presentation looks at the potential and current aerospace use of ALM, of the comparison to other manufacturing processes and of the research path the author has chosen to follow in the SLM of aluminium alloys.  
 
Palaeoclimate and dynamical systems : challenges and promises  
Michel Crucifix (Université Catholique de Louvain)  
3 Dec 2009  Harrison 170 (3D suite) Thursday 2pm  Applied Mathematics 
Palaeoclimate data present important challenges to the climate modeller : sparse data, dating uncertainties, high nonstationarities, and unknown physical constraints at these time scales. On which basis may one formulate tractable problems in such difficult conditions ? First, palaeoclimate do indeed show spatiotemporal structures owing to the effect of orbital elements, and phenomena of bifurcation may be visualised with continuous wavelet transforms. These offer opportunities of empirical model validation and selection, in spite of dating uncertainties. Other methods of identification, for example clustering methods to determine the number of regimes, show promise but will not be adressed here. Second, we do have a physical knowledge of the climate system, but often the physical models employed nowadays lack the dynamical range required to tackle palaeoclimate time scales. Consider this : building a 3000mthik ice sheet over 80,000 years imply a yearly mass imbalance of 37 cm/year : arguably below the precision of current models. Furthermore, physical mechanisms proper to palaeoclimate time scales, such as ice sheet instability, have received little attention in current models. The strategy is therefore to reduce empirically general circulation models, and build on this basis parameterisations that may be used and calibrated at more ambitious time scales. Several challenges, especially regarding stochastic parameterisations and carbon cycling remain unmet. Third, statisticians have been creative at developing parameter estimation methods suitable for dynamical systems. Here we show examples based on an implementation of the particle filter with auxiliary sampling, adapted for the parameter estimation problem. Such algorithm provide a basis to formulate the model calibration and selection problem on a sound statistical basis, making use of prior information obtained with more sophisticated models. The lecture will be articulated around these three themes, with examples based on Pleistocene palaeoclimate time series, simulations with the LOVECLIM earth system model of intermediate complexity, and particle filtering of simple dynamical systems.  
 
Towards the sustainable city? Principles and practice  
Prof. David Butler (University of Exeter)  
1 Dec 2009  Harrison 170 Tuesday 2pm  Informatics RI 
The presentaton asks the question 'what is a sustainable city' and 'would we know it when we saw it'? The aim of the presentation is not to headline gold standard exemplars, but to evaluate the reality of what sustainability means on the ground for largescale housing projects. It describes and discusses the attempts of the government of England and Wales to take the principles embedded at policy level and to begin to roll out new ‘sustainable’ developments in practice, with specific reference to water management. It concludes with another question 'Is the journey towards sustainability more important than the goal'?  
 
New nonlinear mechanisms of midlatitude atmospheric lowfrequency variability  
Alef Sterk (University of Groningen)  
30 Nov 2009  Harrison 170 Monday 2pm  Applied Mathematics 
In this talk we will discuss the dynamical mechanisms potentially involved in the socalled atmospheric lowfrequency variability, occurring at midlatitudes in the Northern Hemisphere. This phenomenon is characterised by recurrent nonpropagating and temporally persistent flow patterns, with typical spatial and temporal scales of 600010000 km and 1050 days, respectively. We study a loworder model derived from the 2layer shallow water equations on a $\beta$plane with bottom topography, which is forced by relaxation to an imposed westerly wind. The loworder model is obtained by a Galerkin projection retaining only the Fourier modes with wavenumbers 0, 3 (zonal) and 0, 1, 2 (meridional). The amplitude of the bottom topography and magnitude of zonal wind forcing are used as control parameters to study bifurcations of equilibria and periodic orbits. In the loworder model equilibria destabilise through Hopf bifurcations, which can be interpreted in terms of mixed barotropic/baroclinic instabilities. These Hopf bifurcations give birth to two families of periodic orbits with different spatiotemporal characteristics. In turn, the periodic orbits bifurcate into strange attractors via the following codimension1 routes to chaos: perioddoublings, breakdown of 2tori, and intermittency. The dynamics on these strange attractors are associated with lowfrequency variability: the vorticity fields show weakening and amplification of nonpropagating planetary waves on time scales of 10200 days. These spatiotemporal characteristics are ``inherited'' (by intermittency) from the two families of periodic orbits and are detected in a relatively large region of the parameter plane. This scenario differs fundamentally from those proposed in the literature so far, which mainly rely on theories involving multiple equilibria. This is joint work with Renato Vitolo (Exeter), Henk Broer (Groningen), Carles Simo (Barcelona), and Henk Dijkstra (Utrecht)  
 
Vertical Discretisations for Coupling the Atmospheric Boundary Layer with the Large Scale Dynamics  
Dan Holdaway  
26 Nov 2009  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
It is now well understood that for modelling the equations describing the large scale atmosphere the CharneyPhillips grid is preferable to the Lorenz grid. Not only does the Lorenz grid give a poorer representation of the dispersion relation, it also supports a single zero frequency computational mode. For modeling the atmospheric boundary layer it is preferable to use a Lorenz grid, otherwise an averaging is required in order to compute the Richardson number. We show, through linearisation and comparison of transients, that vertical configurations can be systematically compared for the boundary layer type problem. This can then be used in order to compare configurations of the complete coupled system and thus to aid in understanding the affect that the boundary layer has on both the computational mode and the overall dispersion relation.  
 
Talking Heads: Creating Realistic 2D & 3D Facial Animations  
Dr Paul Rosin (Cardiff University)  
24 Nov 2009  Harrison 170 Tuesday 2pm  Informatics RI 
This talk will describe ongoing work at Cardiff University for building photorealistic models of faces using active appearance models (AAMs) applied to both 2D image data and textured 3D mesh data. We have applied these models in a variety of contexts: 1/ speech driven animation, in which a combined audio and image model is built and new unseen audio is used to synthesise appropriate an image sequence, 2/ performancedriven animation, in which the animation parameters analysed from a video performance of one person are used to animate the facial model of another person, 3/ production of stimuli for psychological experiments to determine the human perception and judgement of the facial dynamics of smiles, and 4/ biometrics, in which people are identified based on their facial dynamics captured during an utterance.  
 
Numerical experiments for $L_1$norm regularisation in variational data assimilation.  
Melina Freitag (University of Bath)  
23 Nov 2009  Harrison 170 Monday 2pm  Applied Mathematics 
In this talk we give a brief introduction to data assimilation and we show that data assimilation using 4DVar (4D Variation) can be interpreted as some form of Tikhonov regularisation, a very familiar method for solving illposed inverse problems. It is known from image restoration problems that $L_1$norm penalty regularisation recovers sharp edges in the image better than the $L_2$norm penalty regularisation. We apply this idea to 4DVar for problems where shocks are present and give some examples where the $L_1$norm penalty approach performs much better than the standard $L_2$norm regularisation in 4DVar.  
 
Evolution of biological system dynamics  
Orkun Soyer  
19 Nov 2009  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
Systems biology aims to understand the structure and dynamics of biological networks that underlie physiological responses, while synthetic biology ultimately aims to implement such networks. A fundamental question at the crossroads of these two fields is; what is the repertoire of biological networks that can underlie a given response dynamics? Answering this question could allow us to understand how networks underlying a given response would differ in different species and whether there are minimal networks, more amenable for synthetic biology implementations. In this talk, I will illustrate how evolutionary and mathematical approaches can be employed towards reaching such an understanding.  
 
SUPR Models : Models for the Study of the Uncertainty in PalaeoClimate Reconstruction.  
John Haslett (Trinity College, Dublin)  
18 Nov 2009  Harrison LT04 Wednesday 3pm  Applied Mathematics 
We present some modelling challenges that have arisen in the context of our work on palaeoclimate reconstruction. The simplest version of the the problem is as follows. A 10m core of lake sediment contains pollen deposited over the past several millennia. Samples ($n =150$) from along the core are examined under a microscope; each sample is rendered as a multivariate count vector $y^a_i$ of `ancient' pollen. Such vectors describe the composition of the ancient `pollen rain'. As such they provide information on the surrounding vegetation at times in the past; that is, ancient pollen is a `proxy' for ancient climate, for we know from modern data that vegetation composition reflects the climate $c$. Models built on such data, $D^m$, provide information on the probability distribution $\pi[yc, D^m]$. This in turn permits inference $\pi[cy^a_i,D^m]$ on the ancient climates corresponding to the samples. Variations on this are applied to other proxies (eg diatoms) in other archives (eg ocean sediment). At its simplest, palaeoclimate reconstruction returns `best climates' $\hat c^a_i$ corresponding to each $y^a_i$. Our concern in this paper lies with the underlying uncertainties and with the statistical models that we have found to be useful. For example there are many cores, and sample counts thus have spatial and temporal location $(s_i, t_i)$. Individually each $\pi[cy^a_i,D^m]$ is a statement of uncertainty concerning an aspect of a common latent spacetime process $C(s,t)$. How can we formalise the joint statistical inference? Our approach has been Bayesian, and has rested on stochastic process models including: Gaussian (Markov) Random Fields; a novel monotone stochastic process with continuous sample paths, based on a bivariate renewal process; and long tailed random walks with Normal Inverse Gaussian increments. The talk will illustrate their use in this joint inference, and some of the many remaining challenges. There are of course several scientific challenges to the underlying methodology, for example: To what extent can we rely on modern data to tell us about ancient climatevegetation relationships? Is climatechange the only driver of vegetation change. We look forward to some of the statistical challenges that these questions pose. This work has involved collaboration with, and stimulation from, many including Brian Huntley, Andrew Parnell, Mike SalterTownshend, Havard Rue, Alan Gelfand and Caitlin Buck. It has been supported by several grants from Science Foundation Ireland and by a welcome sojourn with Durham University's Institute of Advanced Study.  
 
Codimension two bifurcations arising in a system of phase coupled oscillators  
AnnKatrin Becher (Cologne University, Germany)  
17 Nov 2009  Harrison 170 Tuesday 2pm  Applied Mathematics 
A model of phase coupled oscillators is introduced describing a network with both excitatory and inhibitory interactions. The phase dynamics are modelled by a Kuramotolike system but without symmetries with regard to coupling. The coexistence of inhibitory and excitatory interactions and the asymmetry of coupling give rise to several different scenarios of synchronization. We study the model from the standpoint of bifurcation theory of lowdimensional dynamical systems. Therefore we focus on different configurations of coupling which lead to various bifurcation phenomenons with codimension >1.  
 
Chimera states in heterogeneous Kuramoto networks  
Carlo Laing (Massey University)  
16 Nov 2009  Harrison 170 Monday 2pm  Applied Mathematics 
Since 2002 several groups have studied "chimera states" in networks of identical phase oscillators, in which some oscillators synchronise while the remainder are incoherent. However only in the simplest case did the authors study the stability of such states. I show how to greatly generalise these results to other networks, deriving timeevolution PDEs with as many spatial dimensions as the network. The results emphasise the commonality of the dynamics of different networks, and provide stability information that was previously inferred.  
 
Amorphous structures of rapid phasechange memory materials  
Dr Konstantin Borisenko (Department of Materials, University of Oxford)  
12 Nov 2009  Harrison 170 (3D Vis Suite) Thursday 2pm  Advanced Technologies RI 
Accurate reduced density functions (RDF), which are closely related to the radial distribution functions, can now be routinely obtained from small areas of thin film materials using electron diffraction. The technique provides unique information about distribution of interatomic distances in the material, on the basis of which atomistic models can be built and refined, and then related to the observed properties of the films. This technique has been applied to various materials ranging from metallic glasses to amorphous magnetic films. In this presentation applications of the technique to studies of amorphous phases of rapid phasechange memory materials for information storage are described.  
 
Visualising probabilistic forecasts  
Tim Jupp  
12 Nov 2009  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
We consider the problem of creating maps of ternary probabilistic forecasts. As in traditional (binary) methods, continuous forecast distributions are projected onto discrete ternary forecasts, in which probabilities are assigned to three categories defined by quantiles of the current climatology. Our innovation is to think geometrically and consider each ternary forecast as a point in the triangle of barycentric coordinates (i.e. a 2simplex). This allows us to assign a unique colour to each forecast from a continuum of colours defined on the triangle. We show that a single easytointerpret map can convey full information from a ternary forecast in addition to a measure of the past skill of the forecasting system. Specifically, the forecast at each location is expressed by a circle whose colour encodes the ternary forecast and whose radius encodes past skill. We use the natural symmetries in the problem to assign colours to forecasts using the huesaturationvalue colour system. We derive mathematical measures of subjective certainty H, dominant category theta and misfit R. These measures are used to assign strong colours to forecasts that differ greatly from the climatology, and large circles to regions of high skill. Finally, we show how the concepts of uncertainty, reliability, resolution and calibration (which are usually taken to apply to binary forecasts) can be extended to ternary forecasts. Methods for interpreting these quantities geometrically are proposed. These ideas are illustrated with probabilistic precipitation forecast data from climate model runs, processed using "R" and displayed using "Google Earth".  
 
Environmental implications of water efficiency measures in buildings  
Abdi Fidar (University of Exeter)  
10 Nov 2009  Harrison 170 Tuesday 2pm  Informatics RI 
To encourage the efficient and sustainable use of resources (e.g. energy, water, construction materials) in England and Northern Ireland, the government has introduced ‘Code for Sustainable Homes’. The code requires reduction in per capita water consumption in households, and accordingly provides a rating scheme. Water efficiency related targets can be met using a range of water efficient microcomponents. However, very little is known about their environmental and energy related implications. This paper describes the development of a strategy to quantify the water and energy use of microcomponents and evaluate the environmental performance of composite strategies (comprising different combinations of water efficient microcomponents). A multiobjective optimisation based simulation tool has been developed to investigate the impacts of the composite strategies. Preliminary findings indicate that, depending on the objective (i.e whether to reduce water consumption or greenhouse gas emissions), a trade off is required. For example the analysis of results suggests that (a) energy use and the associated greenhouse gas emissions are largely dependent on how a given volume of water is contributed by the different microcomponents (b) the influence of dishwashers on water consumption reduces significantly when water efficient kitchen taps are present (c) baths do not necessarily use more water than showers (d) in most cases, for a given water consumption, the energy use and the greenhouse gas emissions are inversely proportional to the toilet flush volume.  
 
Using model reduction methods from control theory within variational data assimilation  
Caroline Boess (University of Reading)  
9 Nov 2009  Harrison 170 Monday 2pm  Applied Mathematics 
In this talk the use of model order reduction methods from control theory within variational data assimilation is discussed. The focus is on fourdimensional variational assimilation – a method which requires the minimization of a series of simplified cost functions. These simplified functions are usually derived from a spatial or spectral truncation of the full system being approximated. In this talk a new method for deriving these simplified problems is proposed, based on control theoretic model reduction methods. Moreover, a new model reduction approach for unstable systems is considered. It is shown that this performs well within the state estimation problem occurring in data assimilation.  
 
Reduction of the energy consumption of a highly energy intensive manufacturing process  
Richard de Salis  
5 Nov 2009  Harrison 170 (3D Vis Suite) Thursday 1pm  Advanced Technologies RI (Internal) 
The manufacturing industry is currently undergoing a number of changes to attempt to reduce the energy consumption of their production processes, due to the cost of energy in the current market conditions, and the environmental pressure being placed on them through legislation and consumer opinion. The Ceramic Tile industry is an example of a highly energy intensive sector and as such offers great potential for reduction and the savings this can provide. In this project, work has been carried out with a manufacturer analysing their energy usage, and from this investigating methods which could be used to reduce it. A number of technologies were considered, which will be overviewed, with the conclusion being that in this case the use of energy consumption as an optimisation criterion in their production scheduling will offer the best potential for improvement with their current installed equipment.  
 
What really matters in data assimilation?  
Dan Cornford (Aston University)  
5 Nov 2009  Harrison 101 Thursday 2pm  Applied Mathematics 
In this talk I will consider the state of the art in data assimilation theory, focussing on our recent variational Bayesian approaches, but also discussing path sampling, particle filtering, 4DVAR and ensemble Kalman filters. I will then consider the question of what really matters in data assimilation  in particular I will consider the formulation of the data assimilation problem from a statistical perspective, and try to relate this to the real world application of data assimilation methods in operational settings.  
 
Unsaturated Soil Mechanics: Expansive Soils & Soil Treatment  
Prof Farimah Masrouri and Dr Olivier Cuisinier (LAEGOENSGINPL, France)  
5 Nov 2009  Harrison 170 Thursday 2pm  Informatics RI 
Part I: Expansive Soils Shrinkage and swelling of clayey soils are responsible for a large amount of building damages and give rise to number of questions. This presentation is focused on 3 different points of a research project carried out to contribute to the comprehension of physical mechanisms of this natural hazard and its consequences on lightlyloaded structures. Part II: Stabilisation with lime Quicklime addition is a common technique to improve the physical properties of fine soils and is also known to significantly reduce the swelling ability of expansive soils. One of the main concerns with this practice is the permanence of the stabilization effects brought by the lime addition. This part of the presentation will be focused on a research project that intends to asses the impact of water circulation on the long term behaviour of limestabilised soils.  
 
Dynamics and geometry near resonant bifurcations  
Sijbo Holtman (University of Groningen, NL)  
29 Oct 2009  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
In this talk we focus on nonlinear parameter dependent dynamical systems exhibiting resonance. This phenomenon occurs if oscillatory subsystems interact, while the corresponding frequencies are rationally related. Such a situation appears in many realworld scenarios, e.g., coupled pendula, the moonearth system, and electric circuits. The main goal is to explain the parameter dependence of the qualitative behavior of the dynamics. In particular, we consider the geometry of parameter values for which resonance occurs. It turns out that in the nondegenerate case the geometry is given by the wellknown 2dimensional Arnol'd resonance tongue. A mildly degenerate case corresponds to a more complicated 4dimensional geometry, which we describe in detail. We also present socalled recognition conditions determining to which of these two cases a given resonant family of dynamical systems belongs.  
 
Local Water Symbiosis Approach to More Sustainable Urban Water Management  
Dr Sara Moslemi Zadeh (University of Birmingham)  
27 Oct 2009  Harrison 170 Tuesday 2pm  Informatics RI 
In 21st century, stress on water resources is reaching critical levels due to population growth, rapid urbanization, economic development, climate change, and an ageing infrastructure. An Integrated Water Resources Management approach is urgently needed to secure the equitable and more sustainable management of freshwater to meet environmental, economic and social needs. Greywater treatment and its subsequent use for toilet flushing have been explored as more sustainable water resources management options. However, the infrastructure needs and the disinfectant required for greywater systems make it very difficult to see these systems as environmentally friendly and cost effect (unsustainable), especially for individual households. This is the reason for low uptake of greywater recycling system, particularly in UK. The aim of this project is to test the hypothesis that transferring the concept of industrial symbiosis from industries to urban areas may improve the sustainability of urban water management. The research focuses on greywater reuse among users in residential and office buildings in a local area. The local symbiosis is designed in 3 stages: first, calculating a potential water balance through water reuse and recycling options, including greywater generation; second, identifying or estimating sharing potentials in the area by considering the qualities of the water available for reuse; and finally calculating the optimal scale and mix of users as well as identifying any barriers to implementation. By minimizing the potable water usage, the environmental effect and the cost of the system are reduced.  
 
Compressible Hartmann and mixed EkmanHartmann boundary layers.  
Krzysztof Mizerski (University of Leeds)  
26 Oct 2009  Harrison 170 Monday 2pm  Applied Mathematics 
21st Taylor & Francis sponsored seminar  Taylor & Francis are publishers of the journal "Geophysical and Astrophysical Fluid Dynamics" We consider the effect of compressibility in mixed EkmanHartmann boundary layers on an infinite plane ($z=0$), in the presence of an external magnetic field oblique to the boundary. The aim is to investigate the influence of the magnetic pressure on the fluid density, and hence, via mass conservation, on the mass flow into or out of the boundary layer. We find that if the $z$component of vorticity in the main flow, immediately above the boundary layer, is negative, then there is a competition between Ekman suction and the magnetic pressure effect. Indeed, as the magnetic field strength is increased, the magnetic pumping may overcome the Ekman suction produced by anticyclonic main flow vortices. Such competition may play a role in the solar tachocline, the region of strong shear at the base of the convective zone and a plausible site for the solar dynamo. Here field must be confined until it becomes sufficiently strong that, on escaping, it can rise to the solar surface relatively unscathed, thus giving rise to active regions. The EkmanHartmann boundary layer is the simplest model of a thin region with large shear and a magnetic field; our simplified model may therefore describe some of the important physics of the tachocline.  
 
A model for physicsdynamics coupling  
Bob Beare  
22 Oct 2009  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
Formulations of numerical weather prediction and climate models divide conveniently into the resolved dynamical core and the subgrid physical parametrizations. Improving these components is an ongoing area of research and development. Arguably less examined, however, is the coupling between these components. More research on the physicsdynamics coupling might therefore lead to significant improvements in future model performance. Here, we demonstrate a new approach to physicsdynamics coupling. We compare a full dynamics model with a model explicitly constrained to balance the large scale dynamics and the boundary layer parametrization.  
 
Diagnostic Assessment of Search Controls and Failure Modes in Manyobjective Evolutionary Optimisation  
Prof. Patrick Reed (Penn State University, USA)  
20 Oct 2009  Harrison 170 Tuesday 2pm  Informatics RI 
The growing popularity of multiobjective evolutionary algorithms (MOEAs) for solving manyobjective real world problems, where search failures can have actual economic costs, warrants the careful investigation of their search controls and failure modes. This study contributes a detailed statistical assessment of the search controls and failure modes for a broad range of MOEAs as well as a novel measure of controllability. The comparative analysis applies ten stateoftheart MOEAs on the DTLZ scalable test problems for 27 objectives. From these results, we quantitatively compare the effectiveness and controllability of the algorithms. The study concludes by providing guidance on the top performing algorithms' nonseparable, multiparameter controls when performing manyobjective search.  
 
Using constraintbased optimization to model multilayer buckling phenomena  
Rorie Edmunds (University of Bath)  
19 Oct 2009  Harrison 004 Monday 2pm  Applied Mathematics 
A constraintbased methodology will be presented which has successfully been applied to a solid, elastic, frictional model for parallel folding. Conceived from investigations of the engineering design process, the constraintbased methodology has helped design engineers identify and understand the initial constraints and limitations placed on a system. Written as a set of algebraic expressions the design objectives and constraints can be formulated and optimal solutions found using numerical optimization techniques. A bespoke Constraint Modeller has been created to embrace the methodology. This is able to resolve large systems comprising of over 100 degreesoffreedom using a variety of optimization routines. Parallel folding is representative of multilayer geological systems undergoing buckling deformation and modelling the evolution of folds poses a significant problem. Simplifying down to a two layer formulation, the behaviour of the central interface is modelled using a number of points whose movement is constrained. Looking for least energy solutions, the smalldeflection model closely matches the sequential nature seen in experiments. Using the full largedeflection energy formulation, further phenomena are found which match experimental evidence. Additionally, by altering some of the parameters, the parallel folding model can admit solutions that are kink bandlike in structure. Thus insight is given into the transition between the different foldingtypes seen in nature.  
 
Geoengineering the climate: unthinkable last resort or optimal solution?  
Peter Cox  
15 Oct 2009  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
A Framework for Supporting Rainwater Harvesting in the UK: addressing system design and implementation deficits  
Sarah Ward (University of Exeter)  
13 Oct 2009  Harrison 170 Tuesday 2pm  Informatics RI 
A broad range of recent policy vehicles, such as the Code for Sustainable Homes, Future Water and the Draft Flood and Water Management Bill, are placing increased emphasis on the incorporation of sustainable urban drainage systems (SUDS) within new developments (and, to a lesser extent at present, retrofitting to existing developments). This is in response to both potable water demand reduction and surface runoff source control drivers. Rainwater harvesting (RWH) is one such SUDS technique that can both supplement mains water and attenuate stormwater flows. Putting aside debates on the costbenefit and lifecycle analysis of such systems, the UK is significantly behind other countries, such as Germany and Australia, in implementing RWH. Although the previously mentioned policies promote the use of RWH, there is at present limited enabling of stakeholders (householders, businesses, schools) to implement RWH. This presentation outlines research that has utilised an interdisciplinary approach, undertaking both ‘hard’ and ‘soft’ scientific methods, to establish technical and stakeholder evidence bases related to RWH. Analysis of these evidence bases has resulted in the identification of a number of technical and social ‘implementation deficits’, which hinder the increased uptake of RWH in the UK. Key messages from the evidence bases are derived, resulting in recommendations for restructuring current support mechanisms, having implications for both policy makers and technical innovators.  
 
The liquid top: precession and tides in planetary cores  
Andreas Tilgner (University of Goettingen, Germany)  
5 Oct 2009  Harrison 004 Monday 2pm  Applied Mathematics 
20th Taylor & Francis sponsored seminar  Taylor & Francis are publishers of the journal "Geophysical and Astrophysical Fluid Dynamics"  
 
Heat transfer in turbomachinery predictions with an open source CFD code  
Cosimo Bianchini (Faculty of Engineering, University of Florence)  
1 Oct 2009  Harrison 170 Thursday 1pm  Advanced Technologies RI (Internal) 
Due to the continuously growing need of power and efficiency for turbo engines, combustion chamber temperature has far overcome the metal critical temperature indeed more and more loading the combustor liner and first stages cooling devices. These often critical thermal conditions require a detailed knowledge of the aerothermal behavior of real engine components in order to proceed with improved design. The use of CFD is thus becoming more and more popular among turbine producers also for at design stage of the secondary air system. Dealing with complex geometries, nonaerodynamic bodies, strong temperature and velocity gradients and unsteady phenomena, and ranging the reference Mach from the incompressible limit of the coolant to the transonic regime in the first vanes, it is often very challenging to obtain reliable results and specific tools should be used in order to improve the quality of predictions. The path to make OpenFOAM libraries a reliable tool for heat transfer prediction in turbomachinery is hence illustrated, together with details of the implemented algorithms and models. A wide set of applications of the code to both internal (ribbed and pinned internal channel, impingements) and external (film and effusion holes) cooling are also shown ranging from simple validation test cases to real engine components studied experimentally with Thermo Liquid Crystals.  
 
New type of soil reinforcements  
Prof. Meng Xi (Shanghai University)  
1 Oct 2009  Harrison 170 Tuesday 2pm  Informatics RI 
tba  
 
Computation facilitating insight: from autonomous observation to artificial intelligence  
David Lary (NASA, Goddard Space Flight Center, USA)  
11 Aug 2009  Green Island 1 Tuesday 11am  Met Office/Hadley Centre 
 
"Why the Beauty of your Neighbour's Garden may Belong to You" or "How should we Pay for Urban Water"  
Jim Robinson (University of Waterloo, Canada)  
6 Aug 2009  Harrison 170 Thursday 2pm  Informatics RI 
Many water utilities experience peak summer demands which are very expensive to satisfy, and providing for them can only be achieved at a cost many times per liter what is being charged currently for water. Some utilities are quite interested in using tariff structures, partly because they improve equity by better reflecting real costs of providing for peak demands. Some modelling has shown that 6585% of customers would end up with lower water bills if summer use rates were implemented. However, utility staff feel such rate structures are a lot of work to implement just to improve equity and would be much more interested if there were strong evidence that peak demands will in fact be lowered, and this utility capital spending could be averted. Many utilities would like evidence about effects of peak demand rates to be gathered but would prefer someone else do it. Part of this is nervousness over the public relations issues associated with rate changes. A few brave water companies in the UK have started to collect that evidence, some using innovative experimental techniques. In one 5000 household trial in the UK, a brand new customer or a change of name on an account leads to installation of an automated meter and data logger collecting meter readings every 30 minutes, and assignment to one of five charging regimes all of which are revenue neutral to an average customer. Other utilities have suggested compensating trial participants up front to be more certain that no customer is disadvantaged. The foci of this presentation are to show ways that peak demand pricing trials have been and can be implemented, and to discuss some tentative results and their implications.  
 
Postbuckling response of thinwalled auxetic tubes  
Edward Hirons (SECaM)  
7 Jul 2009  Harrison 107 Tuesday 13:00  Advanced Technologies RI (Internal) 
The project involves examination of the pre and postbuckling response of thin walled tubes loaded under flexure, and comparison to various elastic analytical buckling models. The results of experimental data show that the models are inadequate to predict the limit moment reached by the tubes, due largely to the fact that plasticity is not yet modeled. Work is ongoing to incorporate plasticity and potentialy extend the models' application to similar but distinct geometries, i.e. sandwich panels.  
 
Binocular rivalry  a new model  
Peter Ashwin  
2 Jul 2009  Harrison 106 Wednesday 3.30pm  Applied Mathematics (Internal) 
The effect of binocular rivalry is a wellknown phenomenon in the psychology of perception, where the brain will move between recognition of two conflicting images presented to each eye. It is particularly interesting as a system where the brain constantly "changes its mind" in the absence of any change to the input. This talk will discuss a newly developed model of the author and A Lavric, based on heteroclinic switching.  
 
Topdown versus bottomup  
Daithi Stone (Climate Systems Analysis Group, University of Cape Town, South Africa)  
30 Jun 2009  Green Island 1 Tuesday 11am  Met Office/Hadley Centre 
 
Anomalous diffusion of migrating biological cells  
Rainer Klages (Queen Mary, University of London)  
29 Jun 2009  Harrison 101 Monday 2pm  Applied Mathematics 
 
Groundbased GPS measurements of water vapor: climatology and applications  
Junhong Wang (NCAR, Boulder, CO, USA)  
24 Jun 2009  Green Island 2 Wednesday 11am  Met Office/Hadley Centre 
 
Harper operators, equations and maps: a laboratory for strange nonchaotic attractors  
Joaquim Puig (Universitat Politecnica de Catalunya, Barcelona, Spain)  
15 Jun 2009  Harrison 101 Monday 2pm  Applied Mathematics 
This talk is part of the workshop "Global Dynamics and Applications" held on 15/16 June 2009 in SECaM, University of Exeter. (http://secamlocal.ex.ac.uk/people/staff/rv211/woglodyn09.html)  
 
Phase transitions in statistical physics models  
Barrie Cooper  
11 Jun 2009  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
From a physical point of view, macroscopic properties of a material such as its temperature, structure and magnetisation are determined by the properties and interactions of its constituent microscopic particles. A primary aim of statistical physics is to study these emergent properties of complex systems. Of particular importance are phase transitions, whereupon there is a qualitative change in the macroscopic properties of a system, such as the spontaneous demagnetisation of a ferromagnet at the Curie point. I will describe a family of statistical physics models exhibiting phase transitions and explore how representation theory and the algebraic properties of the operators in such models can help drastically reduce the complexity of the numerical calculations required to detect such a phase transition.  
 
Boundary layer dynamics in extratropical cyclones  
Ian Boutle (University of Reading)  
8 Jun 2009  Harrison 101 Monday 2pm  Applied Mathematics 
19th Taylor & Francis sponsored seminar  Taylor & Francis are publishers of the journal "Geophysical and Astrophysical Fluid Dynamics"  
 
Wave propagation on adapting, inhomogeneous and unstructured grids  
John Thuburn  
4 Jun 2009  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Reinforcement of weak soils: Are we utilising the reinforcement to get the best outcomes?  
Dr Mostafa Mohamed (University of Bradford)  
2 Jun 2009  Harrison 170 Tuesday 2pm  Informatics RI 
In recent years, there has been growing usage of geosynthetic materials for fulfilment of a wide range of functions including improvement of the shear strength of weak soils in order for civil engineering projects to be constructed without the fear of longterm serviceability problems. Reinforcement of surface soils is also used to overcome potential negative consequences for construction in areas that are featured by the inclusion of pockets of soft soils. In general, the behaviour of the reinforced ground relies on the frictional resistance between the reinforcement and surrounding soils. In most of the cases there has been over use of reinforcing layers that never utilises the tensile strength of the reinforcing elements to their utmost. Furthermore, to speed up the construction process, reinforcement is often arranged in a simple manner. The presentation will review the current practice for soil reinforcement highlighting various failure mechanisms. Then it will focus in presenting a new approach to reinforcing the surface soils in which a nominal amount of soil is wrapped around with a layer of geotextile in order to create a wrapped cushion underneath the surface footing. The proposed reinforcement approach shows that significant improvements could be achieved. The presentation will show that the new reinforcement arrangement has the potential to improve the bearing capacity of surface footing several times and to reduce associated settlement. The improvements achieved by the proposed approach are greater than what it could be obtained by the conventional soil reinforcement. Cases in which pockets of soft soils exist will be discussed. Finally, an outline will be given of recent geotechnical engineering research undertaken at the University of Bradford.  
 
Model prediction of component quality in Additive Layer Manufacturing  
Gilian Hatwell  
1 Jun 2009  Harrison 209 Thursday 13:00  Advanced Technologies RI (Internal) 
Additive Layer Manufacturing (ALM) is the generic term applied to a range of high technology processes that are capable of producing netshape or near netshape objects from a variety of input materials. ALM covers a broad range of techniques, but methods utilising lasers to process metallic or polymeric powders are of particular interest to highend engineering manufacturers. The benefits that ALM can provide may have a wide application across many manufacturing sectors. However, this is limited due to concerns about component quality and system repeatability. Previous work has concluded that small variations in the build chamber leads to unacceptable variations in component qualities, particularly mechanical strength. Thermal control systems are already present within ALM processes, and are vital for successful operation, but these are limited and typically only concerned with the corresponding build stage. This seminar looks at the three stages of the PhD; analytical, experimental and computational to build up a generic model predicting the component quality, based on the build conditions (both laser and material parameters) of a polymeric Selective Laser Sintering (SLS) process.  
 
Solitons, homoclinic orbits and exponentially small phenomena in reversible systems  
Tomas Lazaro (Universitat Politecnica de Catalunya, Barcelona, Spain)  
1 Jun 2009  Harrison 101 Monday 2pm  Applied Mathematics 
 
Asymmetric Desynchronization and Ratcheting in Networks of Coupled Oscillators  
Ozkan Karabacak  
28 May 2009  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
We analyze an example system of four coupled phase oscillators and discover a novel phenomenon that we call “heteroclinic ratchet”; a particular type of robust heteroclinic network on torus where connections wind in only one direction. We show that, for coupled phase oscillators, this type of heteroclinic network can exist as an attractor in phase space resulting in asymmetric desynchronization of certain pairs of oscillators. In other words, oscillators with natural frequencies w1 and w2 break synchrony for w1w2>0 but not for w1w2<0. Similarly, when w1=w2, arbitrary small noise results in a break of synchrony such that after the desynchronization the observed frequencies W1 and W2 satisfy W1>W2.  
 
EliassenPalm, CharneyDrazin, and the development of wave, meanflow interaction theories in atmospheric dynamics  
David Andrews (Department of Physics, University of Oxford)  
21 May 2009  Green Island 2 Thursday 2pm  Met Office/Hadley Centre 
 
Satellite observed variability and trends in the global seaice cover  
Josefino C. Comiso (NASA, Goddard Space Flight Center, USA)  
21 May 2009  Green Island 1 Thursday 3pm  Met Office/Hadley Centre 
 
Is the water vapor feedback the same in nature and models?  
Aiguo Dai (NCAR, Boulder, CO, USA)  
20 May 2009  Green Island 1 Wednesday 11am  Met Office/Hadley Centre 
 
Variability of surface temperature in the polar regions as inferred from satellite infrared data  
Josefino C. Comiso (NASA, Goddard Space Flight Center, USA)  
19 May 2009  Green Island 1 Tuesday 2pm  Met Office/Hadley Centre 
 
The effect of mechanical forcing on buoyancydriven flows  
Remi Tailleux (University of Reading)  
18 May 2009  Harrison 101 Monday 2pm  Applied Mathematics 
 
Lfunctions and Arithmetic  
Professor John Coates (Cambridge university)  
14 May 2009  Harrison 101 Thursday 3pm  Pure Mathematics 
 
Reconnection in braided magnetic fields  
Gunnar Hornig (University of Dundee)  
11 May 2009  Harrison 101 Monday 2pm  Applied Mathematics 
 
The higher Hilbert symbol via (phi,G)modules  
Dr Sarah Zerbes (Exeter university)  
7 May 2009  Harrison 101 Thursday 3pm  Pure Mathematics 
 
A SCM modeling by using MultiAgent System (MAS)  
Naihui He (XMEC)  
5 May 2009  Harrison 103 Tuesday 13:00  Advanced Technologies RI (Internal) 
The supply chain is a worldwide network which involves all of those stages from raw material to completed products; while the Supply Chain Management (SCM) is then described as "the integration of all activities" occurring along the supply chain through improved supply chain relationships in order to achieve a suitable competitive advantage. Due to the interior complexity of SCM, SCM modeling has provided a convenient method and become a popular way for scholars to solve emerging problems in a supply chain, such as collaboration and coordination method, and etc. In particular among those modeling approaches, the agentbased technique of MultiAgent System (MAS) that is a branch of Distributed Artificial Intelligence (DAI) encompasses multiple agents with specific roles each of which interacts with others for achieving its local responsibilities and the overall targets, and thereby is able to address the complexity and dynamics of SCM. This seminar will present a simulationbased SCM modeling system by applying the technique of MAS, which involves the specification of the framework of the modeling and its validation processes.  
 
Metals at the tap – how did we get it so wrong and what next?  
Dr Colin Hayes (School of Engineering, Swansea University)  
5 May 2009  Harrison 170 Tuesday 2pm  Informatics RI 
The metals at the tap of greatest concern are lead, copper and nickel, all of which have health concerns (particularly lead). These metals mainly arise from pipes and fittings in the domestic water supply system. Despite apparent EU requirements to mitigate such issues, sampling problems have conspired to substantially diminish corrective action, the big exception being the UK , where 95% of public water supplies are dosed with orthophosphate to suppress plumbosolvency. As sampling deficiencies are rectified, the true scale of problems will emerge. An initial assessment is that 25% of the EU population could be at risk from lead in drinking water. Copper problems appear to be insignificant, whereas nickel problems may also be significant, subject to any future changes in the health based standard. International research networking has potentially influenced the revision of the EU Drinking Water Directive and the implementation of the WHO/UN Protocol on Water and Health. Metals at the tap appear set to climb the international policy agenda. A zonal lead emission model has been developed at Swansea University that can predict compliance with lead standards across an entire City or Town. This is based on a Monte Carlo probabilistic framework and has been validated successfully in numerous case studies. It has been used to optimise phosphate dosing and is currently being used to investigate health risks.  
 
Parity of the rank of an elliptic curve: results  
Dr Tim Dokchitser (Cambridge university)  
30 Apr 2009  Harrison 101 Thursday 4pm  Pure Mathematics 
 
Parity of the rank of an elliptic curve: phenomena  
Dr Valadimir Dokchitser (Cambridge university)  
30 Apr 2009  Harrison 101 Thursday 3pm  Pure Mathematics 
 
A catalogue of singularities  
Jens Eggers (University of Bristol)  
27 Apr 2009  Harrison 101 Monday 2pm  Applied Mathematics 
 
Atmospheric freshwater transport in three generations of the Hadley Centre model  
Jose Rodriguez (Met Office, Exeter)  
7 Apr 2009  Green Island 1 Tuesday 11am  Met Office/Hadley Centre 
 
A Semantic Theory of the Interpretation of a Vague Language  
Dr Brandon Bennett (University of Leeds)  
26 Mar 2009  Harrison 170 Tuesday 3pm  Informatics RI 
I present a semantics for the interpretation of a language that includes vague predicates, based on a refinement and extension of the "supervaluation" approach. The proposed theory provides a formal characterisation of the space of possible precise interpretations (precisifications) of the language, in terms of parameters that specify the applicability of vague concepts by means of thresholds on the values of observable measurements. These observables also determine a set of possible states of the world. Thus the truth of a proposition depends on both the possible world and the precisification with respect to which it is evaluated. On the basis of this semantics, the acceptability of a proposition to an agent is characterised in terms of the agent's beliefs about the world and attitude to admissible interpretations of vague predicates. The theory is applied to analysing certain aspects of the cognitive evaluation of vague information  in particular the sorites paradox. A further extension, in which probability spaces are defined over the sets of possible worlds and precisifications, is used to give a statistical measure of the acceptability of a proposition to an agent.  
 
Sha and Degree 4 del Pezzo Surfaces.  
Prof. Victor Flynn (Oxford University)  
20 Mar 2009  Harrison LT04 Friday 2pm  Pure Mathematics 
 
Topology Optimisation: Challenges and Applications  
Dr H Alicia Kim (Department of Mechanical Engineering, University of Bath)  
19 Mar 2009  Harrison 171 Thursday 2pm  Advanced Technologies RI 
Topology optimisation is considered the most generalised form of structural optimisation. This seminar will discuss two of the most popular methods: SIMP (Solid Isotropic Material with Penalisation) and ESO (Evolutionary Structural Optimisation). Our recent research showed both of the methods are prone to numerical instabilities, due to the use of regular mesh and piecewise constant design variables. This finding supports the recent development of the boundary based approaches such as levelset function methods. Research at Bath has been developing the efficient and convergent optimisation methods and the current research activities will be presented. The seminar will also show two application areas: traditional engineering design and study of bone remodelling.  
 
Skew Power Series Rings  
Prof. Otmar Venjakob (Heidelberg University)  
19 Mar 2009  Harrison 101 Thursday 3pm  Pure Mathematics 
 
Systematic decision analysis for flood risk management  
Hamish Harvey (Newcastle University)  
17 Mar 2009  Harrison 170 Tuesday 3pm  Informatics RI 
Continuing rapid growth in the availability of data and the plummeting cost of computation represents both a great opportunity and a challenge. How can this abundance be utilised to improve the quality of decision making in water management? This opportunity has been grasped in the use of risk analysis in strategic decision making for flood risk management. Risk analysis represents only the first step in a process of development, however, the logical conclusion of which is systematic, quantitative decision analysis. Decision analysis techniques allow the merits of sets of management options to be examined, according to a variety of performance metrics and under a range of possible future conditions. I will outline a conceptual framework for such analyses and discuss the initial design of a software tool that implements it. Our focus is strategic decision making, in which option performance must be assessed over long time horizons. This introduces the need to represent processes of change, for example in demographics or climate, which may be highly uncertain. Early applications of risk analysis have demonstrated some of the opportunity of computational experiments in informing decisions. They have also exposed some aspects of the challenge: the results of these analyses are often opaque and difficult to trust. Properly managed and with the use of appropriate tools, however, the process of setting up and running a decision analysis can lead not only to greater insight but also to improved transparency. Our work sets out to bridge this gap between present reality and future potential.  
 
TBC  
Andrew Gilbert (University of Exeter)  
12 Mar 2009  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Multilayered approach to generalising Digital Terrain Models for 2D Flood Modelling  
Mr Barry Evans (University of Exeter)  
10 Mar 2009  Harrison 170 Tuesday 3pm  Informatics RI 
In surface flow path flood modelling, 2D models are the preferred choices as they can simulate surface flow more accurately than 1D models, they are however more computationally demanding and thereby require greater simulation time. One approach that can be used to reduce the computational time required in 2D modelling is to utilise coarser resolution of data by downsampling the original dataset. Yu and Lane (2006a) showed however that even relatively small changes in model resolution have considerable effects on the predicted inundation extent and the timing of flooding. One of the key causes of changes in the coarse resolution in an urban environment is that of the spreading of buildings into their surroundings and subsequent loss key details such alleyways. This seminar will outline the potential of utilising a multilayered approach for the representation of buildings within a generalised terrain model and the automata processes involved in converting Digital Terrain Model data into a multiple layer generalised grid.  
 
Simulating the stratosphere with HadGEM  
Steven Hardiman (Met Office, Exeter)  
10 Mar 2009  Green Island 1 Tuesday 11am  Met Office/Hadley Centre 
 
TBA  
Chris Jones (University of Leeds)  
9 Mar 2009  Harrison 101 Monday 2pm  Applied Mathematics 
 
Period Domains Modular Forms and Lattices  
Dr Gregory Sankaran (Bath University)  
5 Mar 2009  Harrison 101 Thursday 3pm  Pure Mathematics 
 
Adapting the strategic management of water systems to climate (and other) change  the need for new methods for analysing uncertainty and making robust riskbased decisions  
Peter von Lany (Principal Consultant, Halcrow Group Ltd)  
3 Mar 2009  Harrison 170 Tuesday 3pm  Informatics RI 
Much attention is focused on mitigating factors that contribute to climate change. Mitigation needs to be integrated with actions to adapt to climate (and other) change in ways which do not exacerbate the causes or effects of climate change nor limit the ability of other sectors to adapt. Decision making processes such as the UKCIP Adaptation Wizard (see www.ukcip.org.uk) signal the need for riskbased decision making techniques and methods for analysing uncertainty to help: o determine aspects of water system(s) that are vulnerable to the effects of climate (and other) change o assess the potential risks to the system(s) and the opportunities arising from climate (and other) changes, and their implied costs and benefits o develop adaptive responses to these risks and opportunities to maintain or enhance in a sustainable manner aspects of the system that are most valued. The seminar will outline some recent work that the presenter has been involved in, in the strategic planning of flood risk management and water resources. It will consider the need for new techniques for riskbased decision making and dealing with uncertainty, and identify, for discussion, some of the challenges faced and possible ways forward to dealing with these issues.  
 
Anisotropic elastic properties  
Arnaud Marmier (SECaM)  
2 Mar 2009  Harrison 209 Thursday 13:00  Advanced Technologies RI (Internal) 
Elastic Properties have received a resurgence of interest in the last decades, triggered by the discovery of “negative” properties (Poisson’s ratio –PR– and Linear Compressibility –LC–). The fact that these properties are negative is usually described as anomalous, but more and more materials are discovered that posses a negative Poisson’s ratio, usually in a direction without special symmetry. One of the reasons that negative elastic properties still appear unusual is that the formalism of elastic theory, while conceptually simple, does not lend itself well to the representation of properties, especially offaxis. And at present, there are no easily available, convenient to use, method of calculating elastic properties in any direction. In this seminar I will first describe the theory of elasticity in anisotropic media through the tensor formalism. I will then discuss the ElAM computer code (Elastic Anisotropy Measures), which can represent a variety of elastic properties in any direction. Finally, I will present case studies: direction of extrema in cubic crystals, extreme PR and LC, data mining.  
 
A Hamiltonian approach to variational data assimilation  
Ian Roulstone (University of Surrey)  
2 Mar 2009  Harrison 101 Monday 2pm  Applied Mathematics 
 
The performance of the Hadley Centre Earth System model (HadGEM2)  
Bill Collins (Met Office, Exeter)  
2 Mar 2009  Green Island ? Monday ?  Met Office/Hadley Centre 
 
Air quality forecasting in the UM  
Nick Savage, Carlos Ordonez and Paul Agnew (Met Office, Exeter)  
27 Feb 2009  Green Island 1 Friday 11am  Met Office/Hadley Centre 
 
Extending semigeostrophic theory to include boundary layer diffusion  
Bob Beare (University of Exeter)  
26 Feb 2009  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
Since the seminal work of Hoskins (1975), the semigeostrophic model has proved invaluable in describing the dynamics of meteorological fronts and cyclone formation. The model has also been a focus for the mathematically inclined as, for example, the equations can be proved to be wellposed and can be interpreted in terms of variational principles. However, a weakness of the semigeostrophic model as an interpretive framework for climate models is that it contains no inclusion of the subgrid physical processes such as boundary layer diffusion. In this talk, I will review some of the existing approaches to including boundary layer diffusion in semigeostrophic theory and propose a more accurate formulation.  
 
A Hybrid Generative/Discriminative Framework to Train a Semantic Parser from an Unannotated Corpus  
Dr Yulan He (University of Exeter)  
24 Feb 2009  Harrison 170 Tuesday 3pm  Informatics RI 
We propose a hybrid generative/discriminative framework for semantic parsing which combines the hidden vector state (HVS) model and the hidden Markov support vector machines (HMSVMs). The HVS model is an extension of the basic discrete Markov model in which context is encoded as a stackoriented state vector. The HMSVMs combine the advantages of the hidden Markov models and the support vector machines. By employing a modified Kmeans clustering method, a small set of most representative sentences can be automatically selected from an unannotated corpus. These sentences together with their abstract annotations are used to train a HVS model which could be subsequently applied on the whole corpus to generate semantic parsing results. A filtering method is then used to select the most confident semantic parsing results to generate a fullyannotated corpus which is used to train the HMSVMs. The proposed framework has been tested on the DARPA Communicator Data. Experimental results show that an improvement over the baseline HVS parser has been observed using the hybrid framework. When compared with the HMSVMs trained from the fullyannotated corpus, the hybrid framework gave a comparable performance with only a small set of lightly annotated sentences.  
 
Localised pattern formation  
Jonathan Dawes (University of Bath)  
23 Feb 2009  Harrison 101 Monday 2pm  Applied Mathematics 
 
TBC  
Svitlana Popovych (University of Cologne)  
19 Feb 2009  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
ManinMumford and AndreOort conjectures : a unified approach.  
Dr Andrei Yafaev (UCL)  
19 Feb 2009  Harrison 101 Thursday 3pm  Pure Mathematics 
 
ManinMumford and AndreOort conjectures : a unified approach.  
Dr Andrei Yafaev (UCL)  
19 Feb 2009  Harrison 101 Thursday 3pm  Pure Mathematics 
 
Statistical challenges within the water industry  
Dr Tim Watson (MWH  Business Solutions)  
17 Feb 2009  Harrison 170 Tuesday 3pm  Informatics RI 
The use of statistics is becoming more important within the water industry as a means of developing models that aim to improve the understanding of both the present performance of assets as well as forecasting the future performance of assets. These models, and related forecasts, are typically used to determine short and longterm investment requirements by use of some form of constrained optimization. The accurate estimation of the deterioration and performance of assets over time should be seen as a critical step in the efficient and sustainable allocation of investment spend and ongoing profitability. The modelling process, and the models themselves, therefore need to contain a large helping of statistical rigor and be fit for purpose, to ensure investment plans are robust and as accurate as the data supports. In this presentation, we will present some of the challenges that the water industry face to achieve the above with the constraints of ‘real world’ problems. These challenges are diverse in nature and relate to three key areas, resources, data, and statistical rigor.  
 
Climate change, cities, and the urban heat island  
Mark McCarthy (Met Office, Exeter)  
17 Feb 2009  Green Island 3+4 Tuesday 11am  Met Office/Hadley Centre 
 
Dynamical networks and graph theory  
Markus Kirkilionis (University of Warwick)  
16 Feb 2009  Harrison 101 Monday 2pm  Applied Mathematics 
Nonlinearities like massaction kinetics describe events created by collisions of molecules in a wellmixed environment giving them locally the same probability to meet each other. Moreover this probability is only dependent on the concentration of the mutual partners. In a deterministic approximation the dynamical system describing the evolution of molecular concentrations over time can be interpreted as defining a dynamical network, for example linking species together by the ability to be transformed into each other. Different feedback loops encoded in the nonlinearities will determine the qualitative behaviour of the system. In this talk we are looking at dynamical networks and ask a fundamental but unfortunately hard mathematical question which is currently discussed in many branches of complex systems theory and systems biology: What is the relationship between network topology and qualitative behaviour of such a dynamical network? The answer to this question will depend on what kind of information can be retrieved from different graphs associated to the dynamical system. In this talk I will discuss several such graphs that have been constructed for reaction systems which here will serve as a basic example of a dynamical network in general.  
 
A revised land hydrology in the ECMWF model: a step towards water fluxes prediction in a fullyclosed water cycle  
Gianpaolo Balsamo (ECMWF, Reading)  
13 Feb 2009  Green Island 1 Friday 11am  Met Office/Hadley Centre 
 
Design of a 5Axis Ultraprecision Micro Milling Machine (UltraMill) and its application to micro/nano manufacturing  
Prof. Kai Cheng (University of Brunel)  
12 Feb 2009  Harrison 171 Thursday 2pm  Advanced Technologies RI 
Ultraprecision micro manufacturing is emerging as the key enabling technology for engaging high value manufacturing. Although conventional ultraprecision machines have been used as a major means to manufacture high precision components/products for a few decades, it still remains a big issue in machining high precision 3D miniature/micro components, microstructures and products in terms of predictability, producibility and productivity. Therefore, it is essential and much needed to develop ultraprecision micro machines which are industrially feasible for undertaking micro manufacturing, e.g. having the features of small footprint, high precision, low cost and easy to run, etc. This seminar will present the development of a novel 5axis benchtop micro milling machine  UltraMill. The design considerations and specifications of the machine are discussed against the delicate industrial application requirements. An integrated machine design and analysis approach is described, covering the dynamics of the machine structure, moving components, control system and the machining process, and used to analyze and optimize the entire machine performance at the early design stage. Three prioritized design issues of motion accuracy, dynamic stiffness and thermal stability formulate the holistic design for UltraMill. Furthermore, the approach has been applied to the development of key machine components and their integration so as to enable the machine to achieve high accuracy and fine surface finish. Micro machining trials have been successfully conducted on the machine to produce miniature components and microstructure in a variety of engineering materials. The results have not only verified that the machine renders submicron accuracy and nanometerlevel surface finish, but also demonstrated that benchtop ultraprecision machines would lead to the trend in design of next/future generation of ultraprecision machines. The seminar will conclude with a further discussion on the potentials and applications of the machine in micro/nano manufacturing in particular.  
 
Smoothing geometric maps and applications to KAM theory.  
Alejandra GonzalezEnriquez (University of Exeter)  
12 Feb 2009  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
We show that finitely differentiable diffeomorphisms which are either symplectic, volumepreserving, or contact can be approximated with analytic diffeomorphisms that are, respectively, symplectic, volumepreserving or contact. We prove that the approximating functions are uniformly bounded on some complex domains and that the rate of convergence, in $C^{r}$norms, of the approximation can be estimated in terms of the size of such complex domains and the order of differentiability of the approximated function. As an application to this result, we give a proof of the existence, the local uniqueness and the bootstrap of regularity of KAM tori for finitely differentiable symplectic maps.  
 
On the theory relating changes in areaaverage and pan evaporation  
W. James Shuttleworth (University of Arizona, Tucson, USA)  
11 Feb 2009  Green Island 2 Wednesday 2pm  Met Office/Hadley Centre 
 
System Dynamics Modelling for the simulation of complex hydrological/ water management systems  
Dr Lydia VamvakeridouLyroudia (University of Exeter)  
10 Feb 2009  Harrison 170 Tuesday 3pm  Informatics RI 
System Dynamics Modelling is a methodology for studying and managing complex feedback systems, typically used when formal analytical models do not exist, but system simulation can be developed by linking a number of feedback mechanisms. They are particularly useful for building, understanding and presenting models to nonengineers. This seminar presents the procedure for developing conceptual and System Dynamic Modelling in participatory interdisciplinary context, for a complex hydrological/water management system, the Merguellil valley catchment in Tunisia. The model is being used for studying various water management scenarios for 35 small and one large dam in the Merguellil valley, and their impact to aquifer recharge, under different climatic conditions.  
 
Impact of stratospheric resolution on seasonal forecast skill for Europe  
Andrew Marshall (Met Office, Exeter)  
10 Feb 2009  Green Island 1 Tuesday 11am  Met Office/Hadley Centre 
 
A benchmark for initial perturbations used in ensemble prediction  
Martin Leutbecher (ECMWF, Reading)  
6 Feb 2009  Green Island 1 Friday 11am  Met Office/Hadley Centre 
 
Numerical Methods For Weather and Climate Models  
James Kent (University of Exeter)  
5 Feb 2009  Harrison 101 Thursday 2pm  Applied Mathematics (Internal) 
Numerical models for weather and climate have finite resolution in space and time; the governing equations are solved on the resolved scales while important processes occurring on smaller scales must be represented by subgrid models. The numerical schemes used to solve the resolved scales are not perfect; they suffer from truncation errors. A controversial issue is whether the truncation errors, by accident or by design, can be interpreted as representing some subgrid processes.  
 
Professor  
Professor Nigel Boston (Dublin)  
5 Feb 2009  Harrison 101 Thursday 3pm  Pure Mathematics 
Arboreal representations, factoring iterates, and pextensions  
 
Collaboration resulting from operational use of the UM  
George Pankiewicz (Met Office, Exeter)  
4 Feb 2009  Green Island 1 Wednesday 2pm  Met Office/Hadley Centre 
 
A hidden semiMarkov model for recurrent events  
Theo Economou (University of Exeter)  
3 Feb 2009  Harrison 170 Tuesday 3pm  Informatics RI 
There is a large and rich literature on statistical modelling recurrent events found mainly in the survival and reliability context. Typically the way in which this is done is by assuming a counting process such as the nonhomogeneous Poisson process (NHPP) with a time dependent intensity function (occurrence rate). Sometimes it may be appropriate to use a hidden Markov process formulation to account for the fact that in longitudinal data such as recurrent events data, the subjects in the study undergo changes in time which could possibly depend on the events themselves. In addition it is more appropriate to assume a hidden semiMarkov instead of a Markov process since the latter assumes that the times between each state are geometrically distributed and we believe that this is an unrealistic assumption. The semiMarkov process allows the incorporation of a temporal structure thus increasing flexibility. The hidden semiMarkov model is implemented using MCMC on some illustrative data sets including river floods and water pipe bursts.  
 
Cancelled  
David Raymont (SECaM)  
2 Feb 2009  Harrison 170 Thursday None  Advanced Technologies RI (Internal) 
Cancelled  
 
Computer assisted rigorous hyperbolicity estimates in onedimensional dynamics  
Stefano Luzzatto (Imperial College)  
2 Feb 2009  Harrison 101 Monday 2pm  Applied Mathematics 
 
An evaluation of the MetUM over the central Arctic Ocean using insitu observations  
Cathryn Birch (University of Leeds)  
30 Jan 2009  ? ? Friday ?  Met Office/Hadley Centre 
 
Linear growth of rational points on Chatelet surfaces  
Dr Tim Browning (Bristol university)  
29 Jan 2009  Harrison 101 Thursday 3pm  Pure Mathematics 
 
Does climate change mean it is not worth reducing deforestation in Amazonia?  
Richard Betts (Met Office, Exeter)  
28 Jan 2009  Green Island 1 Wednesday 11am  Met Office/Hadley Centre 
 
Water Resources Management: The Myth, The Wicked, & The Future  
Prof. Patrick M. Reed (The Pennsylvania State University, USA)  
27 Jan 2009  Harrison 170 Tuesday 2pm  Informatics RI 
There is a growing recognition that we must better account for a broader range of process couplings as well as their associated uncertainties to manage the evolving humannatural systems that shape our water resources. These challenges are confounded by and potentially conflict with increasing expectations that engineers facilitate public participation in infrastructure design decisions. Water resources management has long considered these types of challenges. Many valuable historical perspectives have been somewhat lost in the recent water resources management literature. In this talk, I will argue that we are neglecting two key historical lessons as engineers: (1) leastcost optimality in complex humannatural systems is a myth and (2) that water resources management is reflective of a class of wicked social value problems where uncertainties, diverse perspectives, and couplings require collaborative formulation and evaluation of a broad range of design aspirations. Future water resources systems management paradigms must acknowledge wealth—risk tradeoffs, their associated uncertainties, and the potential consequences of limitations in our knowledge of the “chains of causality” operating in complex water systems (will A cause B?). Simultaneous consideration of these factors motivates the need for new frameworks for “constructive” decisionaiding. Decisionaiding can be viewed as a process of collaborative learning and negotiation that can exploit many objective analysis to identify alternatives that capture a broad suite of system behaviors relevant to both modeled and unmodeled objectives, helping decision makers to discover system dependencies and/or tradeoffs and exploit this information in the negotiated management of complex water resources systems. An example of constructive manyobjective decision aiding will be provided for an urban water supply portfolio planning case study for the Lower Rio Grande Valley located in Texas, USA.  
 
Damped wave equations with supercritical nonlinearities  
Sergey Zelik (University of Surrey)  
26 Jan 2009  Harrison 101 Monday 2pm  Applied Mathematics 
 
Orographic precipitation in the tropics: largeeddy simulations and theory  
Dan Kirshbaum (University of Reading)  
22 Jan 2009  Green Island 2 Thursday 2pm  Met Office/Hadley Centre 
 
Autumn 2008 Climate Brief  
Andrew Marshall, Paul James and Tim Legg (Met Office, Exeter)  
21 Jan 2009  Green Island ? Wednesday ?  Met Office/Hadley Centre 
 
Hemispheric transport of air pollution  
Michael Sanderson (Met Office, Exeter)  
20 Jan 2009  Green Island 3+4 Tuesday 3pm  Met Office/Hadley Centre 
 
The Open Hole Tensile Test – A Challenge For Virtual Testing of Composites  
Stephen Hallett (University of Bristol)  
15 Jan 2009  Harrison 107 Thursday 2pm  Advanced Technologies RI 
The open hole tension strength is an important parameter for composite structures since it is can be a limiting factor in design. It is also difficult to characterise and predict through analytical or numerical methods since there exists a wide variation in experimental results depending on testing configuration. Here a range of such variations are presented and the behaviour explained in terms of the development of subcritical damage in the form of intraply splits and interply delaminations and their interaction with each other and also with fibre failure. A finite element based numerical analysis technique has been developed and applied to each case in turn, successfully predicting the failure modes, trends and strengths. This is sufficiently robust to form the basis for a virtual testing framework for the open hole tensile strength of composite materials.  
 
On Geometry of Hilbert Modular Varieties and Applications to Canonical Subgroups  
Dr Payman Kassaei (King's College London)  
15 Jan 2009  Harrison 101 Thursday 3pm  Pure Mathematics 
 
Using Interaction information for clustering variables in causal Bayesian networks  
Michael Barclay (University of Exeter)  
13 Jan 2009  Harrison 170 Tuesday 2pm  Informatics RI 
Mutual information and conditional mutual information functions have been used to learn the structure of variants of naive Bayesian classifiers for several years. Related combinations of these functions have also been used to select relevant but not redundant feature sets. In the case of a causal Bayesian classifier, where the classification variable is not a common parent of the relevant features and where as a consequence hidden variables are often needed, the interaction information function can be shown to be a required, but not sufficient, method for appropriate clustering of variables into parent sets. Several unresolved problems in constructing a final network from the variable clusters are presented for discussion.  
 
Blending in situ and satellite data for monitoring extreme temperatures over land  
Elizabeth Good (Met Office, Exeter)  
12 Jan 2009  Green Island 3+4 Monday 2pm  Met Office/Hadley Centre 
 
Fibrous materials – Hemp, aramid and few others inbetween  
Dr Michael Sloan (XAT)  
6 Jan 2009  Harrison 209 Tuesday 13:00  Advanced Technologies RI (Internal) 
Fibrous materials play an important role in a number of research projects currently running in SECaM and Exeter Advanced Technologies (XAT). This presentation will introduce the fibres and their applications in composite materials. Mike Sloan is an associate research fellow in XAT and has recently completed his PhD titled Ecoefficient friction materials. This work will form the first part of the presentation. The aim of his research was to evaluate the performance of aramid fibres in automotive brake pads and suggest environmentally sustainable replacement fibres such as hemp or flax. The presentation will discuss the analysis of aramid fibres throughout the life of a brake pad from virgin raw material, through to the friction and wear performance of a composite friction material. The effect of substituting natural fibres in a friction material formulation will also be discussed. The second part of the presentation will introduce the Blast curtains project. In this work Helical Auxetic Yarns are being developed and analysed for energy absorbing applications such as blast protection. The construction of a helical auxetic yarn will be shown and the experimental techniques used to evaluate their performance introduced.  
 
Software development practices for climate models: what we've learned  
Steve Easterbrook (University of Toronto, Canada)  
6 Jan 2009  Green Island 1 Tuesday 11am  Met Office/Hadley Centre 
 
The Atmospheric Circulation Reconstructions over the Earth (ACRE) initiative  
Rob Allan and Philip Brohan (Met Office, Exeter)  
16 Dec 2008  Green Island 1 Tuesday 11am  Met Office/Hadley Centre 
 
Atomistic simulation of phasechange memory materials  
Dr. Jozsef Hegedus (University of Cambridge)  
11 Dec 2008  Harrison 107 Thursday 2pm  Advanced Technologies RI 
GeSbTe materials are used in optical DVDs and nonvolatile electronic memories (phasechange randomaccess memory). In both, data storage is effected by fast, reversible phase changes between crystalline and amorphous states. Despite much experimental and theoretical effort to understand the phasechange mechanism, the detailed atomistic changes involved are still unknown. In our work we describe how the entire write/erase cycle for the Ge2Sb2Te5 composition can be reproduced using ab initio moleculardynamics simulations. Deep insight is gained into the phasechange process; very high densities of connected square rings, characteristic of the metastable rocksalt structure, form during melt cooling and are also quenched into the amorphous phase. Their presence strongly facilitates the homogeneous crystal nucleation of Ge2Sb2Te5. As this simulation procedure is general, the microscopic insight provided on crystal nucleation should open up new ways to develop superior phasechange memory materials, for example, faster nucleation, different compositions, doping levels and so on.  
 
Warm rain and climate: VOCALS, CloudSat, models  
Rob Wood (University of Washington, USA)  
11 Dec 2008  ? ? Thursday ?  Met Office/Hadley Centre 
 
Bifurcation analysis of heteroclinic chains involving periodic orbits  
Thorsten Riess  
10 Dec 2008  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
The bifurcation analysis of heteroclinic chains is important for many applications; such chains arise for example in biological models (cells) or physical models (lasers), and their existence is often connected with a rich variety of nearby dynamics. Recently, some of the theoretical and computational tools for the analysis of heteroclinic chains connecting hyperbolic equilibria have been extended to chains connecting hyperbolic equilibria and hyperbolic periodic orbits. The analytical results obtained via an extension of Lin's method can readily be applied to an equilibriumtoperiodicorbit cycle (EtoP cycle), giving rise to bifurcation equations for homoclinic orbits near the EtoP cycle. These analytical results are confirmed by numerical evidence for a concrete example, which is obtained by a computational method to find and continue EtoP connections in parameters. This numerical method is also based on the theoretical framework of Lin's method.  
 
Integrating Genetic Algorithms (GA) with a water system simulator for the multiobjective optimisation of reservoir operation  
Lydia VamvakeridouLyroudia  
9 Dec 2008  Harrison 170 Tuesday 2pm  Informatics RI 
AQUATOR® is a commercial software for developing and running simulation models of natural rivers, water resources and water supply systems, using different operational rules, constraints and priorities. Developed by Oxford Scientific Software, it is being used by several water companies in the UK. The Centre for Water Systems has undertaken the task of linking AQUATOR to a GA optimisation module. Initially GANetXL, an addin for Microsoft Excel®, developed by the Centre for Water Systems, was linked to AQUATOR, for the multiobjective optimisation of reservoir operation. However due to the excessive computational time required, AQUATORGA, a new GA application was developed, using distributed computing, which has been integrated within the AQUATOR environment. This seminar presents a comprehensive overview of the project comprising the mathematical approach and structure of the multiobjective optimisation problem, the development of a prototype as an Excel addin, and the distributed AQUATORGA module that followed.  
 
The mean field approach to the transport of magnetic field  
Alice Courvoisier (University of Leeds)  
8 Dec 2008  Harrison 101 Monday 2pm  Applied Mathematics 
18th Taylor & Francis sponsored seminar  Taylor & Francis are publishers of the journal 'Geophysical and Astrophysical Fluid Dynamics'  
 
padic semistable representations and generalization of the Shafarevich Conjecture  
Professor Victor Abrashkin (Durham University)  
3 Dec 2008  Harrison 101 Thursday 3pm  Pure Mathematics 
Breuil’s theory of semistable padic representations is applied to prove the following property: if X is a projective variety over Q with semistable reduction modulo 3 and good reduction at all other primes then its Hodge number h^{2,0} = 0  
 
Perpendicular magnetic recording and a development of contact recording system.  
Komkrit Chooruang (SECaM)  
2 Dec 2008  Harrison 209 Tuesday 13:00  Advanced Technologies RI (Internal) 
Perpendicular magnetic recording (PMR) is one of the suggested technologies that could postpone the onset of superparamagnetic effects. As the increasing of areal density of the PMR implies that the bit size and head/disk flying heights will have to be decreased in nanometre scales and new media must be developed with improved characteristics. These requirements create a need for instrumentation which can be used to characterise the ultimate performance of heads and media at high recording densities. Therefore, we have developed a contact magnetic recording test system that can help researchers to carry out recording test on different media in order to investigate its performance.  
 
Multiobjective Neural Network Ensembles based on Regularized Negative Correlation Learning  
Huanhuan Chen (University of Birmingham)  
2 Dec 2008  Harrison 170 Tuesday 2pm  Informatics RI 
Negative Correlation Learning (NCL) is a neural network ensemble learning algorithm which introduces a correlation penalty term into the cost function of each individual network so that each neural network minimizes its meansquareerror (MSE) together with the correlation. This paper analyzes NCL in depth and observes that the NCL corresponds to training the entire ensemble as a single learning machine that only minimizes the MSE error without regularization. This insight explains that NCL is prone to overﬁtting the noise in the training set. The paper analyzes this problem and proposes the multiobjective regularized negative correlation learning (MRNCL) algorithm which incorporates an additional regularization term for the ensemble and uses the evolutionary multiobjective algorithm to design ensembles. In MRNCL, we deﬁne the crossover and mutation operators and adopt nondominated sorting algorithm with ﬁtness sharing and linear rankbased ﬁtness assignment. The experiments on synthetic data as well as realworld data sets demonstrate that MRNCL achieves better performance than NCL, especially when the noise level is nontrivial in the data set. In the experimental discussion, we give three reasons why the performance of our algorithm outperforms others.  
 
An anthropogenic influence on El Nino  
Mat Collins (Met Office, Exeter)  
2 Dec 2008  Green Island 1 Tuesday 11am  Met Office/Hadley Centre 
 
Stochastic approximation of fast chaotic Hamiltonian degrees of freedom  
Wolfram Just (Queen Mary, University of London)  
1 Dec 2008  Harrison 101 Monday 2pm  Applied Mathematics 
We restate the problem whether the Hamiltonian dynamics of slow variables coupled to a small number of fast chaotic degrees of freedom can be modelled by an effective stochastic differential equation. Formal perturbation expansions, involving a Markov approximation, yield a FokkerPlanck equation in the slow subspace which respects conservation of energy. A detailed numerical and analytical analysis of suitable model systems demonstrates the feasibility of obtaining drift and diffusion terms and the accuracy of the stochastic approximation on all time scales.  
 
Limits of normal functions and Abel Jacobi maps  
Matthew Kerr (Durham University)  
27 Nov 2008  Harrison 101 Thursday 3pm  Pure Mathematics 
 
TBC  
Renato Vitolo (University of Exeter)  
26 Nov 2008  Harrison 215 Wednesday 10am  Applied Mathematics (Internal) 
 
Tearfund’s Impact on MDG 7  
Frank Greaves (Programme Development Adviser for Water & Sanitation at Tearfund)  
25 Nov 2008  Harrison 209 Tuesday 2pm  Informatics RI 
Tearfund is a Christian relief and development organisation, working in 40 countries worldwide through a network of some 350 partners, and through its own operational arm (the Disaster Management Team). Tearfund’s vision is to empower the local church to bring about transformational change to poor communities. It views the need for water & sanitation as a fundamental cornerstone in development, and acknowledges the effect that access to safe and sufficient water and sanitation has on livelihoods, economic wellbeing, health, and education. In terms of Watsan, Tearfund aspires to work with the church in making the greatest impact possible on achieving Millennium Development Goal 7, Target 10 (“By 2015, to reduce by half the proportion of people without sustainable access to safe drinking water and sanitation”). Our campaign for next year (2009) is that 6 million people will benefit from hygiene education through Tearfund programmes, and of these, by 2015, 3 million people will have improved access to safe water and sanitation facilities (ideally within 500 metres of a water source and 50m of sanitation). We also aspire to see a Global Action Plan for water and sanitation, agreed by world leaders in 2010, and fully implemented globally. This presentation will explore the distinctive Tearfund brings to relief & development in water & sanitation, and will consider:  Applying core development values of sustainability, replicability, empowerment, communityparticipation, holistic (wholeperson) transformation.  Case studies of Watsan programmes which both exemplify and struggle with realising these values: What typifies our successes? and, What typifies our struggles?  Key approaches and concerns:  Sanitation, especially “demandled” approaches, as opposed to “supplydriven”.  Environmental sustainability  Building partner capacity  Mainstreaming gender  Engaging in effective advocacy in Watsan.  
 
Some processes relevant to sulphurbased geoengineering in the lower stratosphere  
Adrian Tuck (Imperial College, London)  
25 Nov 2008  Green Island 1 Tuesday 11am  Met Office/Hadley Centre 
 
Applications of delay differential equations in science and engineering  
Thomas Erneux (Universite Libre de Bruxelles, Belgium)  
24 Nov 2008  Harrison 101 Monday 2pm  Applied Mathematics 
 
Can the stratosphere determine the extratropical circulation response to surface forcing?  
Chris Fletcher (University of Toronto, Canada)  
24 Nov 2008  Green Island 1 Monday 11am  Met Office/Hadley Centre 
 
The Holm NavierStokesalpha equation  
Andrew Soward (University of Exeter)  
19 Nov 2008  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Multiagent modelling and applications to robotics and cognition  
Dr Aladdin Aayesh  
19 Nov 2008  Harrison 203 Wedensday 2pm  Informatics RI 
The link between emotion, cognition and behavior is well investigated in psychological and social studies. In recent years, system developers started to explore, mostly as part of agent technology and the concept of agency, cognition and its potential models that suitable for algorithmic representation, i.e. translation into programs that can work interactively in distributed environment. Emotion modeling has evolved as part of cognitive systems and been recognized as an important aspect of these systems which affects greatly reasoning on its both fronts: representation and inference. This interest in emotions and cognitive agents is helped by advances in games, simulations, and architectures for domestic devices (i.e. robots). Whilst cognitive science is applied into developing cognitive agents, cognitive agents are often used to simulate and test cognitive models and their impact on human perception and responses. The social simulation in particular (e.g. crowd simulation in games) depends on agent technology that utilize some aspect of cognition and behaviorism. Some new studies started to incorporate aspects of emotions to influence agent behavior in a group evolving into an artificial society with emergent social and collective properties, e.g. panic.  
 
The Anglian Water Alliance – Modelling Experiences from AMP4 and future challenges for AMP5  
James Lau (Black & Veatch)  
18 Nov 2008  Harrison 170 Tuesday 2pm  Informatics RI 
The Anglian Water Alliance is a virtual company setup to deliver the AMP4 Capital Delivery program for Anglian Water Plc. The partnership of consultants, contractors and client has formed an effective delivery vehicle focussed on delivering value and innovation. Computational modelling has played a key role in delivering appropriate and cost effective solutions for schemes with varying complexities and problems. This presentation focuses on a number of schemes where novel and innovative approaches have been used. Challenges for AMP5 will also be discussed.  
 
Geoengineering stratocumulus clouds to control global warming: are the sideeffects worse than the cure?  
Jim Haywood (Met Office, Exeter)  
18 Nov 2008  Green Island 1 Tuesday 11am  Met Office/Hadley Centre 
 
Multifractal analysis for nonuniformly hyperbolic dynamical systems  
Thomas Jordan (University of Bristol)  
17 Nov 2008  Harrison 101 Monday 2pm  Applied Mathematics 
 
Personalised Footwear: From Elite to High Street using Rapid Manufacturing  
Dr Candice Majewski (Wolfson School of Mechanical and Manufacturing Engineering, Loughborough University)  
13 Nov 2008  Harrison 107 Thursday 2pm  Advanced Technologies RI 
Rapid Manufacturing encompasses a group of additive technologies used to fabricate enduse parts. A major advantage of this approach is the elimination of the requirement for tooling, thereby allowing production runs of N=1 whilst incurring no cost penalties. This, combined with the geometric freedom achievable with these processes, makes true personalisation of consumer products a viable option. The ~Ł1 million IMCRCfunded integrated project ‘Personalised Sports Footwear: From Elite to High Street’ is investigating the use of Rapid Manufacturing to produce personalised sports shoes, with the aim of enhancing performance, reducing injury, and providing improved functionality. Initially focussing on footwear for elite athletes, the ultimate goal of the project is to allow the general public to purchase fully personalised footwear at an affordable price, by replacing injection moulded outsoles with rapid manufactured alternatives.  
 
Determinant functors for triangulated categories  
Dr Manuel Breuning (Kings College)  
13 Nov 2008  Harrison 101 Thursday 3pm  Pure Mathematics 
 
Modelling and Dynamics of coupled laser  
Hartmut Erzgraber (University of Exeter)  
12 Nov 2008  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Structural similarities and differences in climate responses to CO2 increase between two perturbed physics ensembles  
Tokuta Yokohata (Met Office, Exeter)  
12 Nov 2008  Green Island 1 Wednesday 2pm  Met Office/Hadley Centre 
 
Linking AHP and Social Choice Methods in Group DecisionMaking  
Bojan Srdjevic (University of Novi Sad, Serbia)  
11 Nov 2008  Harrison 170 Tuesday 2pm  Informatics RI 
The social choice (SC) theory is in close relation with multicriteria decisionmaking (MCDM), especially in group decision contexts. SC theory includes various voting systems while MCDM is represented by utility and outranking methods; among utility models, the analytic hierarchy process (AHP) is probably the most popular in group decision support. Two possible contexts in modeling decentralized decision problems in water management will be investigated. The first is based on AHP only and two group aggregation techniques. The second one assumes the AHP application in subgroups, while at a group level, aggregation is performed by the SC voting procedures. Comparative analyses show good agreement of the results when two methodologies are applied as the decision support to the water committee of given river basin. The second methodology is called AHP+SC and is considered more promising for implementation in realdecision situations in water management.  
 
Heteroclinic structures in small motifs of HodgkinHuxley neurons? Indication from a numerical study  
Thomas Nowotny (University of Sussex)  
10 Nov 2008  Harrison 101 Monday 2pm  Applied Mathematics 
 
Out of sight  out of mind  travels of a water engineer  
Jo Parker  
10 Nov 2008  Harrison 102 Monday 1pm  Informatics RI 
Presenter's experiences in Afghanistan, Bosnia, Jamaica, Philippines, Indonesia and Iran focussing on buried assets, leakage detection and water quality/hygiene.  
 
On the Iwasawa theory of abelian varieties over function fields  
Dr Fabian Trihan (Nottingham university)  
6 Nov 2008  Harrison 101 Thursday 3pm  Pure Mathematics 
 
Evidential Reasoning in Water Distribution System Operations  
Josef Bicik (University of Exeter)  
4 Nov 2008  Harrison 170 Tuesday 2pm  Informatics RI 
Due to aging infrastructure, incidents (e.g. pipe bursts) in water distribution systems (WDS) occur on a daily basis and can lead to significant losses of potable water and interruption of service to customers. A method to support decision making of WDS operators in failure situations, based on information fusion using DempsterShafer theory of evidence, will be presented. Information coming from several sources (e.g. telemetry systems, historical records and customer contacts) is combined together to provide the operator with a better insight into the most likely location of a failure in a WDS. The method is placed within the context of a decision support system for near realtime WDS operation and its requirements and potential further developments are identified and discussed.  
 
Is old better than new?  The benefits of remanufactured products to the consumer and society  
M. Errington (XMEC)  
3 Nov 2008  Harrison 106 Thursday 13:00  Advanced Technologies RI (Internal) 
 
Comparing deterministic and stochastic models for cell motility and domain growth  
Ruth Baker (University of Oxford)  
3 Nov 2008  Harrison 101 Monday 2pm  Applied Mathematics 
 
Probing the temporal powerlaw characteristics of the global atmospheric circulation  
Dmitry Vyushin (University of Toronto, Canada)  
30 Oct 2008  Harrison 103 Thursday 2pm  Applied Mathematics 
Climate variability on timescales longer than a year is often characterized by temporal scaling ("power law") behaviour for which spectral power builds up at low frequencies in contrast to rednoise behaviour for which spectral power saturates at low frequencies. We estimate temporal powerlaw exponents ("Hurst exponents") for the global atmospheric circulation of preindustrial control and 20th century simulations for the troposphere and stratosphere. We consider 17 most established climate models from the CMIP3 archive. We show that currentgeneration climate models generally simulate the spatial distribution of the Hurst exponents well. We also use simulations of an atmospheric GCM with different climate forcings to explain the Hurst exponent distribution and to account for discrepancies in scaling behaviour between different observational products. Our analysis demonstrates that at the surface regions of large power law exponents coincide with the regions of strong decadal variability, namely northern North Atlantic, northern and tropical Pacific, and the Southern Ocean. In the free atmosphere these regions are confined to the tropical and subtropical troposphere and stratosphere. The spectral steepness in the former is explained by its strong coupling to the surface and in the later by its sensitivity to the volcanic aerosols. We conclude that this analysis of how climate models capture the falloff of spectral power with frequency provides valuable physical insight into climate variability.  
 
The Manin constant of elliptic curves over function fields  
Dr Ambrus Pal (Imperial College)  
30 Oct 2008  Harrison 101 Thursday 3pm  Pure Mathematics 
We study the padic valuation of the values of normalized Hecke eigenforms attached to nonisotrivial elliptic curves defined over function fields of transcendence degree one over finite fields of characteristic p. Under certain assumptions we compute on the smallest attained valuation in terms of the minimal discriminant. As a consequence we show that the former can be arbitrarily small. We also use our results to prove for the first time the analogue of the degree conjecture unconditionally for infinite families of strong Weil curves defined over rational function fields  
 
Cointegration: an econometric timeseries tool applied to the carbon cycle  
Tim Jupp (University of Exeter)  
29 Oct 2008  Harrison 101 Wednesday 10am  Applied Mathematics (Internal) 
 
Multiobjective league tables  
Richard Everson (University of Exeter)  
28 Oct 2008  Harrison 170 Tuesday 2pm  Informatics RI 
As multiobjective optimisation methods are extended to manyobjective problems, there is a need to visualise the mutually nondominating sets produced. We present a new way of using barycentric coordinates to map a nondominating set onto the plane for visualisation. The fidelity of the mapping is optimised by minimising the graph Laplacian of the nearest neighbour distances graph. League tables ranking, for example, universities are commonly produced by combining making a weighted sum of several measures into a score. Recognising this as a multiobjective problem, we show how to divide the universities into a series of mutually nondominating sets  Pareto shells  and thus provide an unambiguous division into tiers. There are 5 shells for the scores that yield the THES 2008 university league table. We visualise the shells and examine various ways of ranking within a Pareto shell. The effect on the ranking of measurement noise in the scores is evaluated.  
 
Almost Koszul algebras from quantum subgroups  
Dr Barrie Cooper (Exeter University)  
23 Oct 2008  Harrison 101 Thursday 3pm  Pure Mathematics 
 
Designing the dynamics of coupled oscillators  
Peter Ashwin (University of Exeter)  
22 Oct 2008  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
ParetoOptimality of Cognitively Preferred Polygonal Hulls for Dot Patterns  
Antony Galton (University of Exeter)  
21 Oct 2008  Harrison 170 Tuesday 2pm  Informatics RI 
In several areas of research one encounters the problem of generating an outline that is in some way representative of the spatial distribution of a pattern of dots. Several different algorithms have been published which can generate such outlines, but the detailed evaluation of such algorithms has mostly concentrated on their computational and mathematical properties, while the adequacy of the resulting outlines themselves has been left as a matter of informal human judgment. In this paper it is proposed to investigate the perceptual acceptability of outlines independently of any particular algorithm for generating them, in order to determine objective criteria for evaluating outlines from the full range of possibilities in a way that is conformable to human intuitive assessments. For the sake of definiteness it is assumed that the outline to be produced is a simple closed polygon whose vertices are elements of the given dot pattern, all remaining elements of the dot pattern being in the interior of the polygon. It is hypothesised that to produce a cognitively acceptable outline one should seek simultaneously to minimise both the area and perimeter of the polygon, and that therefore the points in areaperimeter space corresponding to cognitively optimal outlines will lie on or close to the Pareto front. A small pilot study was conducted, the results of which lend strong support to the hypothesis. The paper concludes with some suggestions for further more detailed investigations.  
 
Vortices, waves and numerical schemes for mesoscale atmospheric dynamics  
Peter Bartello (McGill University, Montreal, Canada)  
20 Oct 2008  Harrison 101 Monday 2pm  Applied Mathematics 
An overview of recent research on the wave/vortex dynamics of the mesoscale range of the atmospheric energy spectrum will be presented. The presence or absence of these dynamics in a variety of "realistic" models will also be discussed. A few of these reproduce the correct spectrum while most do not. It is argued that this may be attributed to their numerics and/or parameterisation schemes.  
 
Flood rich periods and flood poor periods in the UK's hydrological record  a new way of thinking through 21st century flood risk?  
Stuart Lane (University of Durham)  
20 Oct 2008  Harrison 106 Monday 2pm  Applied Mathematics 
 
Multiple materials patterning using novel a dry powder printer  
Dr. Shoufeng Yang (Queen Mary, University of London)  
16 Oct 2008  Harrison 107 Thursday 2pm  Advanced Technologies RI 
The creation of three dimensional functional gradients by powder processing methods requires the capability to arrange a sequence of two dimensional colour images that can be presented to a solid freeforming device. Planar stacking methods can only achieve a one dimensional gradient. We describe the acoustic control of powder metering and dispensing valves in which the flow rate and switching of powders from a capillary can be controlled using the frequency and amplitude of acoustic vibration from a computer sound card. An orchestra of such valves can be used to pattern layers of powder on the building platform which forms part of a 3axis table.  
 
Algebraic surfaces and hyperbolic geometry  
Prof. Burt Totaro (Cambridge university)  
16 Oct 2008  Harrison 101 Thursday 3pm  Pure Mathematics 
The intersection form among curves on a complex algebraic surface always has signature (1,n) for some n. So the automorphism group of an algebraic surface always acts on hyperbolic (n1)space. For a class of surfaces including K3 surfaces and many rational surfaces, there is a close connection between the properties of the variety and the corresponding group acting on hyperbolic space  
 
Small Gain Theorems and Feedback Loops  Can They Really Be Relevant in Modelling Endangered Plants?  
Stuart Townley (University of Exeter)  
15 Oct 2008  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Urban Water Optioneering Tool  
Evangelos Rozos (University of Exeter)  
14 Oct 2008  Harrison 209 Tuesday 2pm  Informatics RI 
UWOT is a decision support tool that simulates the urban water cycle by modelling individual units (e.g. toilets, washing machines, treatment units, tanks, reservoirs) and assessing their combined effects at the development scale. UWOT simulates not only the standard urban water flows (potable water, wastewater and runoff) but also the water flows (greywater, treated greywater or greenwater – including harvested rainwater) introduced by the advanced water saving and recycling schemes. A hierarchical structure is adopted for the representation of the development water features. The local appliances are at the bottom level of the hierarchy, on a higher level is the household type and at the top level is the development. UWOT is linked with a database that contains information over the major characteristics of each technological category. The selection of technologies for a given urban water cycle configuration may be done manually by the user or may be done automatically by an optimisation algorithm.  
 
Agentbased modelling and optimisation  
Dr O.M. Akanle  
13 Oct 2008  Harrison 107 Thursday 13:00  Advanced Technologies RI (Internal) 
 
A lattice Boltzmann formulation for magnetohydrodynamics with currentdependent resistivity  
Paul Dellar (University of Oxford)  
13 Oct 2008  Harrison 101 Monday 2pm  Applied Mathematics 
 
Rational points of definable sets and diophantine problems  
Dr. Jonhatan Pila (Bristol University)  
9 Oct 2008  Harrison 101 Thursday 3pm  Pure Mathematics 
I will discuss problems and results concerning the distribution of rational points on algebraic and, mainly, certain nonalgebraic sets in $\RR^n$. More specifically, definable sets in ominimal structures. I will describe a result, joint with Wilkie, that such a set $X$ can have only ``few'' rational points, in a density sense, that do not lie on some positive dimensional connected semialgebraic subset of $X$.I will give some applications to problems of AndreOortManinMumford type, including a new proof, joint with Zannier, of the ManinMumford conjecture, and some variant special cases of results of AndreOort and mixed AndreOortManinMumford type.  
 
Rational points of definable sets and diophantine problems  
Dr. Jonhatan Pila (Bristol University)  
9 Oct 2008  Harrison 101 Thursday 3pm  Pure Mathematics 
I will discuss problems and results concerning the distribution of rational points on algebraic and, mainly, certain nonalgebraic sets in $\RR^n$. More specifically, definable sets in ominimal structures. I will describe a result, joint with Wilkie, that such a set $X$ can have only ``few'' rational points, in a density sense, that do not lie on some positive dimensional connected semialgebraic subset of $X$.I will give some applications to problems of AndreOortManinMumford type, including a new proof, joint with Zannier, of the ManinMumford conjecture, and some variant special cases of results of AndreOort and mixed AndreOortManinMumford type.  
 
Astrophysical applications of selfsimilar flows  
YuQing Lou (Tsinghua University, China)  
6 Oct 2008  Harrison 101 Monday 2pm  Applied Mathematics 
17th Taylor & Francis sponsored seminar  Taylor & Francis are publishers of the journal 'Geophysical and Astrophysical Fluid Dynamics' *** Astrophysical research activities at Tsinghua University China are briefly described. We present new results on selfsimilar hydrodynamics and magnetohydrodynamics under selfgravity. Astrophysical applications include star formation, planetary nebulae, stellar collapses, rebound shocks of supernovae, galactic bulge evolution and so forth. We also describe astrophysical voids in selfsimilar expansion.  
 
The Severn Barrage and Other Options  the Environmental Impact  
Prof Roger Falconer (Cardiff University)  
3 Jul 2008  Harrison 171 Thursday 4pm  Informatics RI 
In recent years there has been growing international public concern about climate change, global warming, reducing the carbon footprint, increasing oil prices and the rapid depletion of oil reserves. These issues, as well as others, have led to renewed enthusiasm to consider proceeding with the Severn Barrage, either in the original location proposed by the Severn Tidal Power Group, or at a smaller scale such as the Shoots Barrage. In particular, the Sustainable Development Commission concluded in its 2007 report on ‘Turning the Tide: Tidal Power in the U.K.’ that ‘Electricity from a barrage would displace output from fossilfuelled power stations, making a significant contribution to the UK’s renewable energy targets’. As well as the Severn Barrage there is considerable scope for various forms of tidal renewable energy along the Severn Estuary, as well as the North Wales coast and much of Scotland. The presentation will review the current main Severn Barrage proposals, as originally promoted by the Severn Tidal Power Group, together with giving a brief overview of alternative options such as the Shoots Barrage and Offshore Tidal Impoundments. In particular, emphasis will focus on assessing the potential hydroenvironmental impact of a barrage, including the implications for geomorphological and flood risk changes. Finally, an outline will be given of recent research undertaken by the Hydroenvironmental Research Centre, at Cardiff University, on bacterialsediment interactions and the application of computational hydroenvironmental models to predict the impacts of a Severn Barrage on the tidal currents, sediment transport concentrations and the background bacterial and water quality levels. The presentation will show that the Barrage has the potential to reduce the tidal currents in a highly dynamic estuary. This will lead to reduced suspended sediment loads (particularly upstream of the barrage), increased light penetration within the water column and, potentially, an increase in the benthic biodiversity and the level of aquatic life in the estuary.  
 
Reconciling an emissions model with a climate change model  
Peter Cox and Owen KellieSmith (University of Exeter)  
13 Jun 2008  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
Some climate models take (as inputs or control variables) scenarios of future greenhouse gas emissions and output measures of climate change. The altered climate does not necessarily feed back into the emission scenarios. This workinprogress aims to identify the space of feasible emission scenarios, via a highly simpliﬁed economic model in which emissions are fed back as a model output.  
 
Singapore Membrane Technology Centre, NTU UNESCO Centre for Membrane Science & Technology, UNSW  
Tony Fane (University of Oxford)  
12 Jun 2008  Harrison 171 Thursday 4pm  Informatics RI 
Membrane technologies are now key processes in the water industry. This presentation briefly introduces the various membrane technologies and their historical development as well as trends in costs and energy usage. The potential benefits of membranes are discussed and their roles in water supply, desalination, water reclamation and wastewater treatment are described in terms of stateoftheart, and emerging novel concepts. Singapore provides an interesting case study of how membrane technology can be used in the water cycle. The application of membranes to decentralization is also attractive. Finally the challenges facing membrane technology, including product water quality issues, energy usage and GHG emissions, are discussed.  
 
Low Impact Urban Design and Development  
Jeremy Gabe (Landcare Research)  
10 Jun 2008  Harrison 107 Tuesday 12pm  Informatics RI 
The talk is about the results of current research in New Zealand, mostly on issues related to sustainable urban development (low impact urban design and development).  
 
TBA  
M.L. Wears (SECaM)  
9 Jun 2008  Harrison 209 Thursday 13:00  Advanced Technologies RI (Internal) 
TBA  
 
Determining Convergence Rates: Order of Accuracy vs Function Continuity.  
Dan Holdaway (University of Exeter)  
30 May 2008  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
The relation between order of accuracy and convergence rate for simple linear finite difference schemes for differentiation and advection is examined theoretically and empirically. When a function is sufficiently smooth convergence will be given by the order of accuracy of the scheme. For less smooth functions convergence rate for differentiation can be determined from the function's spectral slope. Convergence for advection of a non smooth function involves an interaction between order of accuracy and spectral slope.  
 
Dynamics of aircraft on the ground  
Bernd Krauskopf (University of Bristol)  
29 May 2008  Harrison 170 Thursday 2pm  Applied Mathematics 
 
Systematic strategies for stochastic modelling of climate variability  
Christian Franzke (British Antarctic Survey, Cambridge)  
19 May 2008  Harrison 203 Monday 2pm  Applied Mathematics 
The climate system has a wide range of time scales for important physical processes, ranging from organized synoptic scale weather systems on a daily time scale, extratropical lowfrequency variability on a time scale of 10 days to months, to decadal time scales of the coupled atmosphereocean system. An understanding of the processes acting on these different time scales is important since all these processes interact with each other due to the nonlinearities in the governing equations. The spatial structure of extratropical variability can be described by only a few teleconnection patterns. The two most prominent examples are the North Atlantic Oscillation (NAO) and the PacificNorth American (PNA) pattern. These teleconnection patterns explain a large amount of the total variability, have a strong impact on surface climate and are related to climate change. In atmosphereocean science, slowly evolving largescale structures like the NAO and PNA, and their statistical behavior, are often of the most interest, and yet the computational power of complex climate models is spent on resolving the smallest and fastest variables in the system. Reduced models for only the most important teleconnection patterns provide computationally feasible alternatives for calculating the statistical behavior of the climatologically relevant slow variables. These reduced models give also insight into the dynamics of the slow variables and their interaction with the unresolved variables. In these reduced models the fast variables are systematically represented by stochastic processes. In my presentation I will discuss systematic strategies to extract reduced stochastic models from data of complex atmospheric circulation models. The stochastic mode reduction strategy accounts systematically for the effect of the unresolved degrees of freedom and predicts the functional form of the effective reduced equations. These procedures extend beyond simple Langevin equations with additive noise by predicting nonlinear effective equations with both additive and multiplicative (statedependent) noises. The stochastic mode reduction strategy predicts rigorously closed form stochastic models for the slow variables in the limit of infinite separation of timescales. Even though there is only a very moderate timescale separation in the atmospheric flows the reduced stochastic models reproduce well the statistics of the complex circulation models. The reduced models have about 10 or less degress of freedom while the complex atmospheirc models have about 1000 degress of freedom.  
 
Cancelled  
Professor Miranda (Plymouth University)  
15 May 2008  Harrison 170 Cancelled 2pm  Informatics RI 
Cancelled  
 
The phase relation between poloidal and toroidal magnetic fields in latitude and longitude observed in the cycles 2223  
Valentina Zharkova (University of Bradford)  
12 May 2008  Harrison 203 Monday 2pm  Applied Mathematics 
 
Numerical wave propagation on the Hexagonal CGrid  
John Thuburn (University of Exeter)  
9 May 2008  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Additive Layer Manufacturing of Aerospace Components  
Danel Johns (UK Airbus Ltd)  
8 May 2008  Harrison 209 Thursady 2PM  Advanced Technologies RI 
 
TBA  
Ingo Fischer (HeriotWatt University, Edinburgh)  
8 May 2008  Harrison 170 Thursday 2pm  Applied Mathematics 
 
Treating Uncertainties in the Realworld Scheduling  
Prof. Sanja Petrovic's (University of Nottingham)  
8 May 2008  Harrison 171 Thursday 4pm  Informatics RI 
Scheduling represents a major issue in modern production planning and control. Ever since the first results of deterministic scheduling theory appeared around 50 years ago, scheduling research has attracted a lot of attention from both academia and industry. Consequently, the scheduling literature is very rich. However, majority of scheduling models and algorithms assume that all parameters are wellknown and precisely defined. However, this is rarely the case in realworld problems where activities are often fraught with uncertainties. This often prevents the results of deterministic scheduling theory from being applied in practice. This talk will introduce a number of realworld scheduling problems and uncertainties that they face. Three ways of using fuzzy sets in scheduling problems will be discussed: (a) in modelling of uncertain scheduling parameters and constraints, (b) in multicriteria decision making in which satisfaction grades of each of the criteria defined to evaluate the quality of the schedules are introduced, and (c) in the rules that schedulers use to draw conclusions based on imprecise premises. Some new directions in raising the level of generality of scheduling algorithms that work well over a range of scheduling problems will be discussed.  
 
Eigenvarieties and padic Banach spaces  
Richard Hill (University College, London)  
8 May 2008  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Rheological characterisation of a commercial glass poly(vinylphosphonate) cement  
P. Brookbanks (SECaM)  
7 May 2008  Harrison 170 Wednesday 13:00  Advanced Technologies RI (Internal) 
: It has been shown that the working and setting properties of traditional glass ionomer cements (GICs) are affected by the cement mixing time. The aim of this study was to explore the effects of mixing time on the working and setting time of a commerciallyavailable glass poly(vinylphosphonate) cement which differs from traditional GICs in that it is based on a copolymer of vinyl phosphonic acid and polyacrylic acid. The working and initial setting time of GICs when using an oscillating rheometer have previously been defined by Wilson and Nicholson. Working time is defined as the time taken for the displacement to reach 95% of the initial displacement value and the initial setting time is when the displacement reaches <5% of the initial displacement value.  
 
Industrial practices and research potential for reverse logistics systems  
Dr Qu Tang (Department of Management and Engineering, Linkoping University, Sweden)  
1 May 2008  Harrison 209 Thursady 1pm  Advanced Technologies RI 
 
Integral Points on Curves of Higher Genus  
Samir Siksek (Warwick)  
1 May 2008  Harrison 106 Thursday 3pm  Pure Mathematics 
For many curves of higher genus, Baker's Theory provides (astronomical) bounds for the size of integral points. I explain how to combine Baker's bounds with the MordellWeil sieve to compute all the integral points on some curves of higher genus. This is based on joint work with Bugeaud, Mignotte, Stoll and Tengely.  
 
Using the past to predict the future: what can we learn from 20th century and last millennium temperature changes?  
Gabi Hegerl (University of Edinburgh)  
28 Apr 2008  Harrison 203 Monday 2pm  Applied Mathematics 
16th Taylor & Francis sponsored seminar  Taylor & Francis are publishers of the journal 'Geophysical and Astrophysical Fluid Dynamics'  
 
An Approach to Machine Musicianship  
Marcelo Gimenes (Plymouth University)  
24 Apr 2008  Harrison 171 Thursday 4pm  Informatics RI 
Marcelo Gimenes investigates the genesis and development of musical styles in artificial worlds. He developed a realtime computer musical system, iMe (Interactive Musical Environments) with which it is possible to observe a number of processes regarding musical perception and cognition and to evaluate how musical influence can lead to particular musical world views. The system has successfully been used in a real performance of a two piano improvisation piece, one of which played by an artificial agent. This experiment allowed the observation of a unique musical experience, connecting the human previous musical background to the complexities of an enhanced human/ machine dialogue  
 
Urban Drainage Modelling in Thames Water  
Andrew Hagger (Thames Water)  
17 Apr 2008  Harrison 171 Thursday 4pm  Informatics RI 
TBA  
 
Image based simulation of large strain deformation of open celled foams.  
B. Notarberardino (SECaM)  
1 Apr 2008  Harrison 170 Tuesday 13:00  Advanced Technologies RI (Internal) 
Open celled foams are used in industrial applications, (e.g. seating, helmets, space vehicles) as well as commonly found in natural structures (e.g. bone, plant stalks, corals). Analytical models and experimental tests have been carried out by a number of material scientists to gain an understanding of the influence the complex relationship between the parent material properties and the architecture of the foam has on the resultant effective physical properties. Computational modelling offers the prospect of providing a deeper understanding than experimental tests of the mechanisms at work during deformation and more realistic model results than can be achieved via analytical approaches. However the difficulty of meshing the complex topologies of foam microarchitectures has proved, until recently, a barrier to effectively using the most popular of physics based simulation techniques for mechanical characterisation: the finite element method. In the present study, for the first time, a new image based meshing approach ScanFE is used to obtain geometrically and topologically accurate finite element meshes of open celled foams based on 3D imaging data. The finite element models were used in an explicit code, LSDYNA®, to characterise the quasistatic through to dynamic stressstrain behaviour of the materials for various compression velocities and for both linear elastic and elastoplastic material properties from small strains right through to strains well into the compaction regime. Both endplate contacts and general foam to foam contact of the cell walls with sliding were modelled.  
 
Multiobjective Ant Colony Optimisation: A Metaheuristic Approach to Supply Chain Design  
L. Moncayo (SECaM)  
17 Mar 2008  Harrison 203 Thursday 13:00  Advanced Technologies RI (Internal) 
This paper proposes a new approach to determining the supply chain (SC) design for a product mix comprising complex hierarchies of subassemblies and components. For the supply chains considered, there may be multiple suppliers that could supply the same components as well as optional manufacturing plants that could assemble the subassemblies and the products. Each of these options is differentiated by its lead time and cost. Given all the possible options the supply chain design problem is to select the options that minimise the total cost while keeping the total lead time within required delivery due dates. This work introduces Pareto Ant Colony Optimisation as an especially effective metaheuristic for solving the problem of SC Design. A number of ant colonies generate a Pareto Optimal Set of SC Designs in which only the non dominated SC designs allow ants to deposit pheromones over the time and cost pheromone matrices. An experimental example is used to test the algorithm and show the benefits of utilising two pheromone matrices and multiple ant colonies in SC optimisation problem.  
 
Modelling the atmospheric boundary layer  
Bob Beare (University of Exeter)  
14 Mar 2008  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
The atmospheric boundary layer is the turbulent layer above the Earth's surface with a thickness between 100m and 2km. It is responsible for exchange of momentum, heat and moisture between the surface and the free atmosphere, so is an important component of the climate system. This talk describes simulations of the atmospheric boundary layer as it changes from it's weak turbulence state at night to its strong turbulence in the day. The mixed phase state between the night and day time turbulence is defined more precisely than before and is shown to scale strongly with wind shear.  
 
KALYPSO – An Open Source Software Tool for Flood Studies in Rivers  
Professor Erik Pasche (Hamburg University of Technology)  
13 Mar 2008  Harrison 171 Thursday 4pm  Informatics RI 
As a result of climate change, urbanization and landuse changes, floods are becoming more frequent and causing increased loss and damage to property and life. The EU water policy reacted with a paradigm change in its water policy from blocking off flood prone areas (with dikes and walls) to give water more space and live with the flood. The consequence is the need to expand the relationship between the city, space and water and to improve stakeholders’ capacity to adapt to flood risk. These new guidelines for flood management require a good understanding about the impact of river morphology and anthropogenic changes on the flow regime in rivers and on the probability of inundation. Research Activities in the last decades have considerably improved this understanding leading to sophisticated mathematical fluvial flow models. They range from 1dimensional unsteady flow models to 2 and 3dimensional hydrodynamic models, which make use of refined roughness concepts and turbulence approaches and accomplish a high resolution of the topography. The engineering world should have access to theses instruments in a most flexible and efficient way being able to combine 1 and 2dimensional models (hybrid modeling), to select refined roughness concepts for vegetated flood plains (physically based roughness modeling) and to compare different turbulence approaches. Also the enormous amount of geographical data calls for an efficient and versatile data management and visualization tool. Thus present research concentrates more on model integration and data mining than model generation. Since two years a team of researchers at the Institute of River & Coastal Engineering at TUHH/Hamburg together with engineers from Björnsen Consulting Engineers Koblenz have developed such an integration shell for fluvial flow modelling called KALYPSO (www.kalypso.wb.tuharburg.de). This Open Source software system for flood risk modelling is based on OGCstandards (www.opengeospaial.org) and provides an Open GIS user interface for mapbased data access and input. A Web Map Service (WMS) based on an implementation of the Open Source software deegree (www.deegree.org) provides access to GISdata via Internet. With a work flow browser the user is guided through the tasks of flood modelling in a logical order including various tools for grid generation and boundary data management (preprocessing), for defining and starting the simulation cases (processing) and for analysing and visualization of the simulation results in inundation maps, flood damage maps and flood risk maps (postprocessing). For the modelling of fluvial flow hybrid modelling technique is available integrating 1 and 2dimensional discretization elements and St. Venant and Shallow Water Equations. This new modelling shell for fluvial floods will be presented and its theoretical concept illustrated. The hybrid modelling technology, the data mining functionality and the open GISbased GUI will be explained and its application demonstrated at real cases of fluvial floods  
 
Modular forms and Galois representations over imaginary quadratic fields  
Tobias Berger (Cambridge)  
13 Mar 2008  Harrison 106 Thursday 3pm  Pure Mathematics 
In joint work with Gergely Harcos I strengthened a result of Taylor on associating Galois representations to cuspforms over imaginary quadratic fields. I further present a result (joint with Kris Klosin) on the modularity of ordinary, residually reducible Galois representations of imaginary quadratic fields.  
 
Stability of rolls in rotating magnetoconvection with physically realistic boundary conditions  
Olga Podvigina (Russian Academy of Sciences, Moscow, Russia)  
12 Mar 2008  Harrison 173 Wednesday 11am  Applied Mathematics 
15th Taylor & Francis sponsored seminar  Taylor & Francis are publishers of the journal 'Geophysical and Astrophysical Fluid Dynamics' *** We consider small amplitude Boussinesq convection in a horizontal layer rotating about a vertical axis with an imposed vertical magnetic field. Rigid electrically insulating no slip horizontal boundaries held at constant temperature are assumed. Depending on parameter values, convection at the onset can be steady or oscillatory. For the steady onset of convection rolls can emerge in a supercritical or subcritical bifurcation of the trivial steady state, and they can be unstable with respect to the same rolls flow rotated by an arbitrary angle. We study, for which parameter values convection at the onset is steady or oscillatory, and how stability of small amplitude rolls depends on the parameters.  
 
My Evil Determinant Problem  
Robin Chapman (University of Exeter)  
11 Mar 2008  Harrison 103 Tuesday 9am  Pure Mathematics (Internal) 
 
Optimization of ergodic averages  
Oliver Jenkinson (Queen Mary, University of London)  
10 Mar 2008  Harrison 209 Monday 2pm  Applied Mathematics 
 
Meanfield equations for weakly nonlinear twoscale perturbations of forced hydromagnetic convection in a rotating layer  
Vladislav Zheligovsky (Russian Academy of Sciences, Moscow, Russia)  
10 Mar 2008  Harrison 203 Monday 11am  Applied Mathematics 
14th Taylor & Francis sponsored seminar  Taylor & Francis are publishers of the journal 'Geophysical and Astrophysical Fluid Dynamics' *** We consider stability of regimes of hydromagnetic thermal convection in a rotating horizontal layer with free electrically conducting boundaries, to perturbations involving large spatial and temporal scales. Equations governing the evolution of weakly nonlinear mean perturbations are derived under the assumption that the alphaeffect is insignificant in the leading order (e.g., due to a symmetry of the system). The meanfield equations generalise the standard equations of hydromagnetic convection: New terms emerge  a secondorder linear operator representing the combined eddy diffusivity, and quadratic terms associated with the eddy advection. If the perturbed CHM regime is nonsteady and insignificance of the alphaeffect in the system does not rely on the presence of a spatial symmetry, the combined eddy diffusivity operator also involves a nonlocal pseudodifferential operator. If the perturbed CHM state is almost symmetric, alphaeffect terms appear in the meanfield equations as well. Near a point of a symmetrybreaking bifurcation, cubic nonlinearity emerges. All the new terms are in general anisotropic.  
 
Convection in rotating cylinders: asymptotic theory and numerical simulations  
Keke Zhang (University of Exeter)  
7 Mar 2008  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Forecasting complex systems: it's about dynamics, it's not about statistics  
Kevin Judd (University of Western Australia, Perth, Australia)  
6 Mar 2008  Laver 320 Thursday 12.00  Applied Mathematics 
In 1963 Edward Lorenz published a paper that changed the way scientists think about the prediction of geophysical systems. Two years earlier, Rudolf Kalman had published a paper that changed the way engineers thought about prediction of electronic and mechanical systems. In recent years geophysicists have become increasingly interested in Kalman filters, where as engineers have become increasingly interested in chaos. I will argue that prediction of complex systems like the weather has more to do with nonlinear dynamics than it has to do with linear statistics. A position with which I think both Lorenz and Kalman would likely agree. I will attempt to show why attractors, shadowing trajectories, nonlinear filters, optimal control, and other concepts from nonlinear dynamics are important in weather prediction, by first illustrating the ideas with Lorenz's 1963 example of a chaotic system, then confirming these results by experiments with an operational weather forecasting model.  
 
Fundamental groups of hyperbolic curves and the principle of Birch and SwinnertonDyer  
Minhyong Kim (University College, London)  
6 Mar 2008  Harrison 106 Thursday 3pm  Pure Mathematics 
 
period domains, modular forms and lattices  
Dr Gregory Sankaran (Bath University)  
5 Mar 2008  Harrison 101 Thursday 3pm  Pure Mathematics 
 
HopfGalois Module Structure of Tame Extensions of Prime Power Degree  
Paul Truman (University of Exeter)  
4 Mar 2008  Harrison 103 Tuesday 9am  Pure Mathematics (Internal) 
A major result in local Galois module theory is Noether's Theorem, that given a finite Galois extension of local fields L/K, the ring of integers OL is free over the integral group ring OK[G] if and only L/K is at most tamely ramified. In HopfGalois module theory, the Galois group is replaced by a (possibly nonunique) Hopf algebra, giving a socalled HopfGalois structure on the extension, and the behaviour of OL in this HopfGalois structure is studied. We present a generalisation of Noether's Thereom to this setting for Galois extensions of prime power degree.  
 
Revealing the ghost in the machine: noise and population dynamics  
Tim Benton (University of Leeds)  
3 Mar 2008  Harrison 101 Monday 2pm  Applied Mathematics 
 
A dwelltime approach to the stability of switched linear systems  
Özkan Karabacak (University of Exeter)  
29 Feb 2008  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
Switched linear systems arise as examples or generalizations of hybrid systems, especially in control engineering. A switched system consists of a family of different subsytems and a set of signals that controls the switching between these subsystems. In this talk switched linear systems and its stability problems will be introduced in general. One of these, namely, finding a sufficient condition on the minimum dwell time of the switching signal that guarantees the stability of switched linear systems will be considered and a new approach to this problem will be presented. The proposed method interprets the stability of switched linear systems through the distance between the eigenvector sets of subsystem matrices. Thus, an explicit relation in view of stability is obtained between the family of the involved subsytems and the set of admissible switching signals.  
 
Zeeman's nerve impulse model  
Martin Krupa (New Mexico State University, Las Cruces, NM, USA)  
28 Feb 2008  Newman D Thursday 2pm  Applied Mathematics 
In early 1970's E.C. Zeeman proposed a three dimensional model of the dynamics of a neuron. The model is a slow/fast ODE with one fast variable and two slow ones and is a caricature of the HodgkingHuxley equation. In this talk we analyze the model of Zeeman using methods of geometric singular perturbation theory and blowup, veryfying the numerical predictions of the dynamics of the model. As a part of the analysis we discuss the dynamics near a singularly perturbed cusp.  
 
Water Distribution System Modelling and Calibration  
Daniel Kozelj (University of Ljubljana)  
28 Feb 2008  Harrison 171 Thursday 4pm  Informatics RI 
The seminar will present the Slovenian experience on water distribution system modelling together with the fields of calibration, sampling design and optimisation. An overview will be given on the aforementioned issues and project results will be presented. The projects presented will include: (1) Calibration of a WDS model by Genetic Algorithms (part of Ljubljana WDS – 35,000 inhabitants), (2) Sampling Design for Calibration of WDS by GA (Sezana – 11,000 inhabitants), (3) Rehabilitation of a WDS by GA (Logatec – 11,000 inhabitants) and (5) Experiences of modelling WDS and macrocalibration (Skofja Loka – 22,000 inhabitants and Celje – 65,000 inhabitants). Finally, the role of the tools in facilitating these processes will be discussed based on the findings of the real life applications.  
 
Arithmetic properties for partitions with nonrepeating odd parts  
James Sellers (Pennsylvania State)  
28 Feb 2008  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Some examples of local Galois module structure in characteristic 0 and characteristic $p$.  
Nigel Byott (University of Exeter)  
26 Feb 2008  Harrison 103 Tuesday 9am  Pure Mathematics (Internal) 
Let $L/K$ be a totally ramified abelian extension of local fields, with Galois group $G$. A basic question in Galois module structure is to determine when the valuation ring $S$ of $L$ is a free module over its associated order in the group algebra $K[G]$. When $K$ is a finite extension of $\mathbb{Q}_p$ (the characteristic $0$ case), Y.~Miyata has given a freeness criterion for a large family of {\em cyclic} extensions of degree $p^n$. In this talk, I will give an alternative formulation of Miyata's criterion, and will present work in progress (joint with Griff Elder), where the same freeness criterion arises for {\em elementary abelian} extensions of the field $K=\mathbb{F}_q((T))$ of formal Laurent series over a finite field (the characteristic $p$ case).  
 
Magnetoseismology of the solar atmosphere: does really wag the tail the dog?  
Robert Erdelyi (University of Sheffield)  
25 Feb 2008  Harrison 209 Monday 2pm  Applied Mathematics 
 
Magnetic fields in star formation  
Daniel Price (University of Exeter)  
22 Feb 2008  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
Magnetic fields are observed in sufficient strengths to be important at every stage of the star formation process, from the dynamics of the interstellar medium in galaxies, in turbulent molecular clouds and in individual star forming cores. I will discuss our attempts to incorporate magnetic fields into numerical simulations of the fragmentation of dense cores and of star cluster formation from turbulent initial conditions using a Smoothed Particle Magnetohydrodynamics algorithm.  
 
Growth in linear algebraic groups: an approach through incidence  
Harald Helfgott (Bristol)  
21 Feb 2008  Harrison 106 Thursday 3pm  Pure Mathematics 
Let K be R, C or a Z/pZ. Let G = SL_2(K). Not long ago, I proved the following theorem: for every subset A of G that is not contained in a proper subgroup, the set A\cdot A\cdot A is much larger than A. A generalisation to groups of higher rank was desired by many, but seemed hard to obtain. I shall now present a proof somewhat different from the first one. The role of both linearity and the group structure of G should now be clearer. A few ideas towards a generalisation will be discussed, with a focus on the case of SL_3(Z/pZ).  
 
WDS Pressure Management for Water Loss Reduction: State of the Art  
Julian Thornton (Thornton International Ltd.)  
19 Feb 2008  Harrison 215 Tuesday 4pm  Informatics RI 
Water distribution system pressure management encompasses several approaches and has a number of important benefits; it has been referred to as “the preventative method par excellence” of water loss management. Changes in leak flow rates and some components of consumption are now reasonably predictable however there has been little published data as to how improved management of excess pressures and surges can influence new break frequency of mains and services. This discussion will encompass the types of pressure management utilized in the industry today, how to assess potential volume benefits from pressure management and the challenge which lies ahead to improve the industry understanding of how to assess pressure break frequency relationships. Several case studies will be cited during the discussion.  
 
On The Rank of Classgroups of Quadratic Function Fields  
Andreas Schwiezer (University of Exeter)  
19 Feb 2008  Harrison 103 Tuesday 9am  Pure Mathematics (Internal) 
 
Estimation of the correlation decay rate for chaotic intermittency maps  
David Natsios (University of Liverpool)  
18 Feb 2008  Harrison 203 Monday 11am  Applied Mathematics 
Chaotic intermittency maps give a nonlinear, nonGaussian method of generating long memory time series. In particular we study the symmetric cusp map, the asymmetric cusp map, polynomial maps and logarithmic maps. In previous studies by Bhansali and Holland, it has been shown that these maps can simulate stationary time series with a full range of values for the long memory parameter, including d = 0.5 which is usually considered nonstationary, d = 0 which is usually considered short memory and d < 0 which is usually intermediate memory. This gives us the opportunity to carry out a simulation study to investigate the robustness of various long memory estimation techniques in extreme cases and when the assumptions of linearity and Gaussian distribution no longer hold. We show that standard methods can give large bias and we introduce an extended dual parameter long memory model, which includes the standard oneparameter fractional difference model as a special case and also accommodates a boundary behaviour of the type not admissible in the standard model. We also consider extensions of the chaotic intermittency maps, including stochastic versions and a bivariate version of the polynomial map. Our dual parameter methods of long memory parameter estimation are once again compared to standard methods and methods of distinguishing between the stochastic maps are introduced.  
 
Machine learning in astronomy: time delay estimation in gravitational lensing  
Peter Tino (University of Birmingham)  
18 Feb 2008  Harrison 209 Monday 2pm  Applied Mathematics 
A ray of light (or any other form of electromagnetic radiation, e.g. radio or xrays) travels along a geodesic, which could be locally curved due to the gravitational effect of clumps of matter like stars or galaxies. This is known as gravitational lensing. Gravitational lensing, caused by intervening matter along the line of sight, can give rise to interesting cosmic illusions like magnified and seriously distorted images of distant sources, sometimes splitting into multiple images. Since the distortion of the images depends on the distribution of matter in the lensing object, this is the most direct method of measuring matter (which is often dark) in the Universe. Quasar Q0957+561, an ultrabright galaxy with a super massive central black hole was the first lensed source to be discovered and it is the most studied so far. Gravitational lens creates two distinct images of Q0957+561. We attempt to recover the phase shift in the 2 lensed images of Q0957+561 using a model based approach formulated within the framework of kernel regression. In a set of controlled experiments emulating presence of realistic observational gaps, irregular observation times and noisy observations, we compare our method with other stateofart statistical methods currently used in astrophysics. We then apply the method to actual observations doubly imaged quasar Q0957+561 at several radio and optical frequencies.  
 
Nanoflares in the solar corona  
Mitchell Berger (University of Exeter)  
15 Feb 2008  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
Solar flares are magnetic storms in the sun's atmosphere. The distribution of flare energies is a power law over several orders of magnitude. The smallest flares (nanoflares) may be responsible for heating the coronal plasma to over a million degrees. The nature of nanoflares is unknown, as they are below observational resolution. In the 1980s Parker suggested that nanoflares occur when braided magnetic flux tubes reconnect. This talk gives a model of flux tube braiding and reconnection similar to selforganized forest fire models, with a power law energy distribution.  
 
Can Metallurgy Have a New Life?  
Professor Z Fan (BCAST (Brunel Centre for Advanced Solidification Technology))  
14 Feb 2008  Harrison 215 Thursday 2pm  Advanced Technologies RI 
Metallurgy, as a black art, has made marks on every single step of human civilization. Today, metallic materials have become the backbone of any nation’s economy. The global metals production is over 2 billion tonnes per annual. However, metallurgy as a research subject appears to be saturated, no major or exiting development; metallurgy as an industry is regarded as “sunsetting”; metallurgy as an educational subject cannot attract enough interests for young kids to sign in as metallurgical students. The overall picture for metallurgy is indeed very gloomy. In this presentation, I will take snap shots in the metallurgical history to examine critically the causes of the current problems. Possible solutions to such problems will then be presented in terms of new research directions, industrial reorganisation and new strategies for sustainable exploitation of natural resources. Some examples will be drawn from our own research to illustrate such new directions and new strategies.  
 
Water & Sewerage Capital Maintenance Risk Modelling  
Nathan Muggeridge, and Mark RandallSmith (Mouchel Parkman)  
14 Feb 2008  Harrison 170 Tuesday 4pm  Informatics RI 
The Water Companies are required to prepare Asset Management Plans (AMP) every 5 year and these determine the level of charges for water and sewerage services. The Asset Management Plan for the period between 2010 and 2015 is currently being prepared and OFWAT, the water industry Regulator, requires the capital maintenance elements of the plans to adopt a riskbased approach. This presentation provides an insight into the preparation of an Asset Management Plan for water and sewerage infrastructure, and demonstrates the role of research in the development of the plans. It will also highlight some of the current problems with implementing a riskbased approach to capital maintenance.  
 
Semistable models of modular curves  
Adam Joyce (Bristol)  
14 Feb 2008  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Bayesian learning from the last glacial maximum on climate sensitivity  
Hermann Held (Potsdam Institute for Climate Impact Research, Potsdam, Germany)  
11 Feb 2008  Harrison 209 Monday 2pm  Applied Mathematics 
13th Taylor & Francis sponsored seminar  Taylor & Francis are publishers of the journal 'Geophysical and Astrophysical Fluid Dynamics'  
 
The Impenetrable Hedge – some thoughts on propriety, equitability and consistency  
Ian Jolliffe (University of Exeter)  
8 Feb 2008  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
In weather and climate forecasting, hedging is said to occur whenever a forecaster’s judgment and forecast differ, and it is usually taken as evident that hedging is undesirable. Forecasts are often judged by computing a verification measure or score. A number of different scores are available in most circumstances, and to choose between them, various desirable properties of scores have been defined. Three ‘desirable’ properties of scores are linked to the idea that hedging should be avoided, namely propriety, equitability and consistency. It is fair to say that none of these properties is fully understood. This talk will provide some clarification and new insights, as well as some historical background. Nearly as many questions are raised as are answered.  
 
Low Energy and Sustainable Cooling of Underground Railway Systems  
Jolyon Thompson (Research Engineer  Cooling the Tube Programme)  
7 Feb 2008  Harrison 170 Tuesday 4pm  Informatics RI 
Underground railway system usage is growing throughout the developing world and in many cities the underground railway is the most commonly used form of public transport. The intense service provided on these systems generates substantial quantities of rejected heat energy. This energy can significantly increase air temperatures within the trains and tunnels. When coupled to high ambient temperatures this can lead to passenger discomfort and health issues. Conventional air conditioning systems have been used in some modern underground railway installations but their operation has had limitations and leads to highly energy intensive solutions. Conventional air conditioning often cannot be included in older systems through heat rejection and spatial problems. Sustainable cooling systems could reduce the overall system energy usage and provide an acceptable environment for passengers. These could include energy management methods such as reduced train velocity, low weight carriages as well as sustainable cooling technologies that have been introduced from modern building services engineering such as Groundwater and geothermal cooling. However due to the increased complexity of the air flow paths, the increased heat density and the transient nature of the situation the problem provides many unique and difficult engineering challenges. Most low energy and sustainable systems that could be used on underground railways have been developed and used in more conventional building services applications. Ventilating an underground railway environment, in which there is to be heavy traffic of electricallypropelled rapidtransit trains, differs from those normally encountered in conventional buildingservices applications. The heat generated by the train motors and electric lighting, together with body heat from passengers, is so great that excessive temperatures would prevail in summer when limited cooling is available. During this seminar the drivers behind the low energy and sustainable cooling will be briefly looked at and some possible methods will be briefly discussed. The seminar will then provide detailed discussion of groundwater cooling, evaporative cooling and geothermal cooling. The seminar will finally conclude with some general remarks about the objectives and strategies of introducing sustainable and low energy cooling to an operating underground railway.  
 
The anabelian geometry of Grothendieck  
Mohamed Saidi (University Of Exeter)  
5 Feb 2008  Harrison 103 Tuesday 9am  Pure Mathematics (Internal) 
I will explain what the Grothendieck anabelian conjectures are and how did Grothendieck come to them. I will give an overview on the state of these conjectures and my contribution to the subject.  
 
Physical Properties of Palladium Thin Films in a an Hydrogen Atmosphere  
R. Matelon (SECaM)  
4 Feb 2008  Harrrison 215 Monday 13:00  Advanced Technologies RI (Internal) 
TBA  
 
Control of beams and plates: a mathematical perspective  
Mark Opmeer (University of Bath)  
4 Feb 2008  Harrison 209 Monday 2pm  Applied Mathematics 
 
The dynamics of wheel shimmy or good memory causes trouble  
Gabor Orosz (University of Exeter)  
1 Feb 2008  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
The lateral vibration of towed wheels, called shimmy, may appear on airplane landing gears, motorcycle wheels, caravans, rear wheels of semitrailers and articulated buses, and it usually presents a safety hazard. The dynamics of wheel shimmy is studied when the vibrations are related to the elasticity of the tyre. In the corresponding stretchedstring tyre model, the nonholonomic rolling constraint is described by a partial differential equation (PDE) that is coupled to an integrodifferential equation (IDE) governing the lateralwheel motion. The coupled PDEIDE system can be transformed to a delay differential equation (DDE) by assuming travelling wave solutions along the contact patch. Investigating the stability of the stationary rolling motion reveals intricate stability charts where instabilities lead to periodic and quasiperiodic vibrations. These vibrations are found by numerical simulation and verified by experiments.  
 
Evolving the Water Industry to the Next Generation (With a Satistical Bent)  Lessons We Can Learn from Other Industries  
Tim Watson (MWH UK Ltd)  
31 Jan 2008  Harrison 170 Tuesday 4pm  Informatics RI 
The recent drive within the water industry has been towards ‘whole of life’ costing, necessitating the need for robust and quantifiable forecasting of asset performance. However, it is generally accepted that data is sparse, unreliable, and of poor quality. Therefore, constructing robust statistical forecasting models remains a challenge. In this talk, we will highlight the above problem with two examples. Firstly, we believe that the current OFWAT directive of ‘business as usual’ – embedding a decision support system within the assets themselves – is an excellent first step to begin to populate the necessary data sets. Secondly, as a comparison to the water industry, we will provide examples from other industries where such a ‘business as usual’ undertaking has been achieved over the past 10 years, resulting in an environment that is data rich and therefore able to produce robust forecasts of future investment.  
 
The relative kernel group of an order and SK_1  
Steve Wilson (Bristol)  
31 Jan 2008  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Aerosol modelling in the Unified Model and their importance in global weather and climate  
Duncan Ackerley (University of Reading)  
28 Jan 2008  Harrison 209 Monday 2pm  Applied Mathematics 
 
Second mean analysis of stochastically perturbed population dynamics  
Iakovos Matsikis (University of Exeter)  
25 Jan 2008  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
Population Projection Matrices (PPM's) are mathematical models that describe the evolution of age or stageclassified populations. These models usually are stochastically perturbed, due to environmental reasons and their asymptotic dynamics are governed by the resulting spectra (Lyapunov exponents). This mean asymptotic analysis however, do not give satisfactory answers regarding the PPM's transient behavior. In this talk we study stochastically perturbed PPM's using second mean techniques. We plot pseudospectra and variance envelopes which capture the transient dynamics and discuss nonnormality of matrices and its implications in the population's transient evolution.
 
 
On the efficient use of uncertainty when performing expensive ROC optimisation  
Dr Jonathan Fieldsend (UoE)  
24 Jan 2008  Harrison 171 Thursday 3pm  Informatics RI 
When optimising receiver operating characteristic (ROC) curves there is an inherent degree of uncertainty associated with the operating point evaluation of a model parameterisation x. This is due to the finite amount of training data used to evaluate the true and false positive rates of x. The uncertainty associated with any particular x can be reduced, but only at the computation cost of evaluating more data. Here we explicitly represent this uncertainty through the use of probabilistically nondominated archives, and show how expensive ROC optimisation problems may be tackled by only evaluating a small subset of the available data at each generation of an optimisation algorithm. Illustrative results are given on data sets from the well known UCI machine learning repository.  
 
The acoustics and stability of swirling flow  
Nigel Peake (University of Cambridge)  
21 Jan 2008  Harrison 209 Monday 2pm  Applied Mathematics 
 
Designing objects from the insideout  
Dr. Siavash H. Mahdavi (Complex Matters)  
17 Jan 2008  Harrison 106 Thurday 2PM  Advanced Technologies RI 
Currently, when choosing a material to be used for a particular product, the best fit material for the task is found from a predefined set of materials (wood, steel, plastic…). Often, it is necessary to modify the original design of the product due to material constraints. At Complex Matters our approach is different. We think that it is better to look at the application first and then design a material, with the use of 3D imaging and rapid manufacturing, from the ground up, essentially designing our own microstructure. This results in a lighter, better suited product that can also exhibit material properties that were previously unattainable.  
 
Rectilinearity Measure for Detecting Buildings on Satellite Images  
Dr Jovisa Zunic (UoE)  
17 Jan 2008  Harrison 171 Thursday 3pm  Informatics RI 
Rectilinear structures often correspond to humanmade structure, and are therefore justified as attentional cues for further processing. For instance, in aerial image processing and reconstruction, where building footprints are often rectilinear on the local ground plane, building structures, once recognized as rectilinear can be matched to corresponding shapes in other views for stereo reconstruction. Perceptual grouping algorithms may seek to complete shapes based on the assumption that the object is question is rectilinear. Using the proposed measure, such systems can verify this assumption.  
 
Chiral Smart Honeycombs  
W. Miller (SECaM)  
14 Jan 2008  Harrison 203 Thursday 13:00  Advanced Technologies RI (Internal) 
TBA  
 
Towards the seamless prediction of weather and climate  
Tim Palmer (ECMWF, Reading)  
14 Jan 2008  Harrison 203 Monday 2pm  Applied Mathematics 
 
Bursting dynamics in the neuronal systems  
Abul Kalam AlAzad (University of Exeter)  
11 Jan 2008  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
Bursting is a relatively slow rhythmic alternation between an active phase of rapid spiking and a quiescent phase. It is exhibited by a wide range of nerve and endocrine cells, including pancreatic betacells, respiratory pacemaker neurons, dopaminergic neurons of the mammalian midbrain, thalamic relay cells, and pyramidal neurons of the neocortex. One of the major challeges in the theoretical neuroscience is to understand the dynamical and computational properties of bursters, and their underlying physiological mechanism both in the single cell and network levels. We examine synchronization phenomena in varying parameter regime for the bursting neuronal systems governed by standard minimal models, and emergence of clustering in the ensuing dynamics. We also present a method to compute the stability of the subspace formed by partial synchronous clusters.  
 
TBA  
Dr Richard Everson (UoE)  
10 Jan 2008  Harrison 170 Tuesday 2pm  Informatics RI 
TBA  
 
Convection and magnetic stability of the planetary cores  
Sergey Starchenko (IZMIRAN, Troitsk, Russia)  
7 Jan 2008  Harrison 209 Monday 2pm  Applied Mathematics 
 
Invasion Dynamics: Resilient vs. Vulnerable Populations  
Stuart Townley (University of Exeter)  
7 Dec 2007  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
In this talk we consider two interacting populations  a resident and an invader.
From uncertain models of each population we want to determine if the invader, initiated with negligible density, can dislodge the resident from steady state carrying capacity. Adopting robustness tools from control engineering, we show that resilience (robustness of non invasion) and vulnerability (non robustness and transient interactions) can be captured from pseudospectrum plots of linearised invasion matrices.  
 
Research Performed at the Aerospace Structures Laboratory Faculty of Aerospace Engineering  
Prof. Haim Abraovich (Aerospace Structures Laboratory Faculty of Aerospace Engineering, Technion, I.I.T, Haifa, Israel)  
6 Dec 2007  Harrison 106 Thursady 2PM  Advanced Technologies RI 
The research performed at the Aerospace Structures Laboratory Faculty of Aerospace Engineering, Technion,I.I.T, Haifa, Israel. consists on two main topics: stability and dynamics of thin walled laminated composite structures and smart structures applications. An overview will be given on both topics.  
 
Sewer Infrastructure Capital Maintenance  Theory and Practice  
Alec Erskine (MWH UK Ltd)  
6 Dec 2007  Harrison 170 Tuesday 2pm  Informatics RI 
A discussion of the impact of the Common Framework on asset management in the water industry particularly the sewerage infrastructure. Attempts to apply risk theory and cost benefit analysis to the CCTV inspection of sewers prior to intervention. What actually happens in practice at selected water companies.  
 
Vinogradov's three primes revisited  
Andrew Booker (Bristol)  
5 Dec 2007  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Real Life MCDM Applications in Water Resources Management: Case Studies – Serbia and Brazil  
Prof. Bojan Srdjević (University of Novi Sad)  
4 Dec 2007  Harrison 209 Tuesday 4pm  Informatics RI 
An overview of two real life applications will be presented: (1) Serbian Case Study  Participative decisionmaking at regional hydro system level based on AHP methodology (Nadela system in Vojvodina Province); and (2) Brazilian Case Study  Assessment of water allocation scenarios in a reservoir system by combined use of river basin simulation models and MCDM methods (Tandem reservoirs França and Săo Jose de Jacuípe in Paraguacu river basin, Bahia). The AHP multicriteria method will be presented in brief as well.  
 
The Fluid Dynamics of Lymphatic Vessels  
A. McDonald (SECaM)  
3 Dec 2007  Harrison 209 Thursday 13:00  Advanced Technologies RI (Internal) 
TBA  
 
Palaeomagnetic field and palaeoclimatic changes: observations from China  
Yongxin Pan / Rixiang Zhu (Chinese Academy of Sciences, Beijing, China)  
3 Dec 2007  Harrison 209 Monday 2pm  Applied Mathematics 
12th Taylor & Francis sponsored seminar  Taylor & Francis are publishers of the journal 'Geophysical and Astrophysical Fluid Dynamics'  
 
A model for the pure bending of isotropic tubes: beyond the Brazier effect  
Khurram Wadee (University of Exeter)  
30 Nov 2007  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
Tubular structures are common in engineering and biological settings. They provide an efficient way of carrying load but are also susceptible to elastic instabilities. Under conditions of pure bending, thin tubes are known to ovalize; the basic theory was formulated exactly 80 years ago but assumed that the ovalization occurs uniformly along the length of the tube. In this talk a novel treatment will be presented which identifies other routes to instability that provide a better approximation to the real behaviour of tubes. Furthermore, this new formulation is applicable to tubes made of auxetic or orthotropic materials.  
 
System Dynamics Modelling (SDM) for the Simulation of Complex Water Systems  
Lydia S. VamvakeridouLyroudia (University of Exeter)  
29 Nov 2007  Harrison 170 Tuesday 2pm  Informatics RI 
System Dynamics Modelling (SDM) is a methodology for studying and managing complex feedback systems, typically used when formal analytical models do not exist, but system simulation can be developed by linking a number of feedback mechanisms. They are particularly useful for building, understanding and presenting models to nonengineers. Moreover they are useful for developing models in participatory interdisciplinary context, as is the case for most European Commission (EC) projects. This seminar presents the procedure for developing SDM for complex water systems within the EC FP6 project AQUASTRESS, followed by two specific application case studies.  
 
Selfpoints on elliptic curves  
Christian Wuthrich (Nottingham)  
29 Nov 2007  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Asymptotics of large bound states of localised structures  
Jon Chapman (University of Oxford)  
26 Nov 2007  Harrison 209 Monday 2pm  Applied Mathematics 
 
Cat's eyes and Landau poles  
Matt Turner (University of Exeter)  
23 Nov 2007  Harrison 254 Friday 10 am  Applied Mathematics (Internal) 
The relaxation of a smooth two–dimensional vortex to axisymmetry is examined, after an instantaneous, weak external strain ﬁeld is applied. In this limit the disturbance decays exponentially in time at a rate that is linked to a pole of the associated linear inviscid problem (known as a Landau pole). As a model of a typical vortex distribution that can give rise to cat’s eyes, here distributions are considered that have a basic Gaussian shape but whose proﬁles have been artiﬁcially ﬂattened about some radius rc . A numerical study of the Landau poles for this family of vortices shows that as the location rc is varied, so the decay rate of the disturbance moves smoothly between poles as the decay rates of two Landau poles cross. Cat’s eyes which occur in the nonlinear evolution of a vortex lead to an axisymmetric azimuthally averaged proﬁle with an annulus of approximately uniform vorticity, rather like the artiﬁcially ﬂattened proﬁles investigated. It is found that ﬁnite thickness cat’s eyes can persist (i.e. the mean proﬁle has a neutral mode) at two distinct radii, and in the limit of a thin ﬂattened region the result that vanishingly thin cat’s eyes only persist at a single radius is recovered. The decay of non–axisymmetric perturbations to these ﬂattened proﬁles for larger times is investigated and a comparison with the result for a Gaussian proﬁle is made.  
 
Physical Modelling of Venford Dam Spillway  
Professor Godfrey Walters (University of Exeter)  
22 Nov 2007  Harrison 170 Tuesday 2pm  Informatics RI 
Following a request from South West Water, a physical model of the spillway structure and toe works of Venford Dam on Dartmoor was built at a 1:20 scale in the Fluids Laboratory. This talk outlines the background to the study, the theoretical and practical details of constructing the model, and the outcomes of a series of tests on the existing structure and proposed amendments.  
 
Siegel modular forms and representation numbers of quadratic forms  
Lynne Walling (Bristol)  
22 Nov 2007  Harrison 106 Thursday 3pm  Pure Mathematics 
Number theorists love to count things, especially integral objects. An example is to count the number of ways an integral quadratic form represents each integer, where the variables of the quadratic form are only allowed to assume integral values. More generally, we can ask to count the number of ways a quadratic form represents a lower dimensional quadratic form. These representation numbers are encoded in the Fourier coefficients of generalized theta series, which are examples of modular forms. When counting representation numbers of integers, the associated theta series is a function of one complex variable, whereas to count representation numbers of rank n quadratic forms, the associated theta series is a function of an n by n symmetric complex matrix. We will discuss these theta series, with particular attention given to the Hecke operators and the information they provide regarding representation numbers.  
 
Maximumentropy velocity profiles and boundary layer theory in turbulent flow  
Robert Niven (University of New South Wales, Canberra, Australia)  
21 Nov 2007  Harrison 107 Wednesday 2pm  Applied Mathematics 
The maximum entropy method of Jaynes (1957) is used to determine the "most probable" steadystate velocity profile u(y) in several "classical" fluid flow systems, including axial flow in a cylindrical pipe (Poiseuille flow) and flow between parallel plates. In each case, the analysis yields an analytical solution for the velocity profile over the complete spectrum of laminar to turbulent flow, as a function of the maximum velocity u_{max} and a momentum parameter M. In each case, the predicted profile reduces to the wellknown laminar solution at M = 0, whilst for M > 0 it gives an equation which supersedes the semiempirical correlations commonly used for turbulent flow profiles. The main steps of the analysis and the predicted profiles are presented here. The analysis is then used to derive a new maximumentropy laminarturbulent boundary layer theory, for the velocity profile in steady flow along a flat plate. For M = 0, this reduces to the laminar boundary layer theory given in some texts, which approximates the PrandtlBlasius solution to the NavierStokes equation. For turbulent flow, it yields a previously unreported set of solutions.  
 
Solitary surface waves on fluids in electric fields  
Paul Hammerton (University of East Anglia)  
19 Nov 2007  Harrison 209 Monday 2pm  Applied Mathematics 
 
Maximum Entropy Production in planetary atmospheres  
Tim Jupp (University of Exeter)  
16 Nov 2007  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
Atmospheric motions constitute a heat engine. As energy flows down temperature gradients from the tropics to the poles, so entropy is produced. Observations, and numerical simulations, suggest that the terrestrial atmosphere produces entropy at the "maximum possible rate". The currently developing theory of Maximum Entropy Production (MEP) provides a framework for interpreting these observations. In this talk I shall give an overview of MEP theory and its application to planetary atmospheres. In particular, the influence of surface drag on atmospheric entropy production is examined. A simple dynamical model is used to give insight into previous numerical results. The dependence of the MEP state on parameters such as planetary radius and rotation rate is then used to extrapolate the results to other planets.  
 
Crystalline representation and Fcrystals  
Fabien Trihan (Nottingham)  
16 Nov 2007  Harrison 171 Friday 3pm  Pure Mathematics 
Let K be a complete discrete valuation field of mixed characteristics. Assume its residue field has a finite pbasis. Then there exists an equivalence of category between the category of crystalline representations of the absolute Galois group of K, with HodgeTate weights in {0,1} and the BarsottiTate groups over the ring oif integers of K.  
 
Lessons from BedZED  
Chris Shirley Smith (Director of Water Works UK Ltd)  
15 Nov 2007  Harrison 170 Tuesday 2pm  Informatics RI 
The lecture will cover the development of BedZED as planned, the construction period and the water management plan. Things did not go entirely as planned and the lessons which can be drawn from the project are opened for viewing and subsequent discussion.  
 
Magnetic Recording & Hard Disk Drive Technology  
B.C. Choo (SECaM)  
14 Nov 2007  Harrison 215 Wednesday 13:00  Advanced Technologies RI (Internal) 
TBA  
 
Invariant polygons in systems with grazingsliding  
Robert Szalai (University of Bristol)  
12 Nov 2007  Harrison 209 Monday 2pm  Applied Mathematics 
 
Relaxation Oscillations arising in the Thermal Convection of Rapidly Rotating Spherical Systems  
Ed Blockley (University of Exeter)  
9 Nov 2007  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
This work will make up the final chapter of my thesis and is concerned with studying the behaviour of the following PDE system:
which has been modified from the complex GinzburgLandau equation (CGLE) studied in previous work by the addition of a temperature gradient and thermal diffusion timescale .
Starting from the limit (for which we recover the CGLE featured in Blockley et. al.) we reduce and observe how the behaviour of the system changes becoming quasiperiodic before breaking down to chaos.  
 
Atomistic Simulation of Oxide/Oxide Interface  
Andrada Maicaneanu (BabesBolyai University, Department of Chemical Technology, Romania)  
8 Nov 2007  Harrison 209 Thursady 2PM  Advanced Technologies RI 
When supported, thin films demonstrate remarkable structural transformations, with important implications for catalysis, sensors, electrochemistry, semiconductors or superconductors. At present, the tools available to characterize solidsolid systems cannot provide atomic level resolution of, for example mixed screwedge dislocations. Therefore atomistic simulation can provide an invaluable complement to experiment. In this work atomistic simulation was employed to generate models of oxide thin films. First an atom deposition methodology was used to create an SrO thin film on a BaO(001) support. The evolution of the thin film from small clusters (submonolayer coverage), to five atomic layers, which includes cracks in its structure, was studied. Specifically, information related to growth and nucleation processes can be explored using this methodology. Secondly an amorphisation and recrystallisation methodology was developed to explore the more complex system, that of ceria deposited on zirconia and yttrium stabilized zirconia. Simulated amorphisation and recrystallisation involves forcing the thin film to undergo a transformation into an amorphous state prior to recrystallising and therefore the recrystallisation process rather than the (perhaps artificial) initial structure will dictate the final structure. The recrystallisation process enables the evolution of all the important structural modifications as the thin film evolves structurally in response to the support. These include dislocations (pure edge and mixed screwedge), dislocation networks, grainboundaries and defects (interstitials, vacancies and substitutionals, including complex defect association) all within a single simulation cell.  
 
Recent Advances in Data Assimilation in Large Scale Hydrodynamic and Hydrological Forecasting Models  
Henrik Madsen (DHI (Danish Hydraulic Institute))  
8 Nov 2007  Harrison 170 Tuesday 2pm  Informatics RI 
The use of data assimilation in hydrodynamic and hydrological forecasting systems has advanced considerably in recent years. This talk gives a review of the developments, considering the data assimilation problem within a general filtering framework. This framework incorporates updating of different modelling components in the forecast system, including model forcing, model state, and model parameters. It includes as a special case the classical Kalman filter. Various extensions of the filter especially tailored towards operational applications are reviewed. These include (i) approximate Kalman filter schemes that utilize costeffective approximations of the error modelling, (ii) combination of filtering and forecasting of model prediction errors, (iii) filtering with coloured or biased model errors, and (iv) application of regularization techniques.  
 
Pattern transformation induced by an elastic instability  
Tom Mullin (University of Manchester)  
5 Nov 2007  Harrison 209 Monday 2pm  Applied Mathematics 
 
A Review of Mantle Convection  
Francisco Pla (Depto. de Matematicas, Facultad de Ciencias Quimicas and IMACI, Universidad de CastillaLa Mancha)  
2 Nov 2007  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
The formation of the rocks indicates that viscosity in the interior of the Earth and planets strongly depends on temperature, and this inﬂuence is the fundament for understanding the mantle convection and subduction motions. This is the goal for which a convection problem with temperaturedependent viscosity in the NavierStokes equations is studied. The dimensionless hydrodynamics equations are considered in which the viscosity is an exponential function of the temperature ν(T ) = ν0 · exp(−γT ). This work studies the timedependent solutions in codim2 zones for different aspectratios, Rayleigh numbers, exponential rate γ and other parameters. A bifurcation study with the stability results for constant viscosity and variable viscosity are also exposed. This work is by Francisco Pla and Henar Herrero, Depto. de Matematicas, Facultad de Ciencias Quimicas and IMACI, Universidad de CastillaLa Mancha and Ana Maria Mancho, Instituto de Matematicas y Fisica Fundamental, Consejo Superior de Investigaciones Cientiﬁcas.  
 
Water Distribution Network System Modelling in China: Opportunities and Challenges  
Professor Hongbin Zhao, Director, Water and Wastewater Systems Research Center (Harbin Institute of Technology, China)  
1 Nov 2007  Harrison 170 Tuesday 2pm  Informatics RI 
There is a large demand in modelling water distribution networks and systems in China, and with that, a huge potential market for modellers and model developers. However, the modelling community in China is still relatively small in size compared to Western countries, and research and development in still relatively slow. This talk will attempt to: (i) discuss and summarise various hurdles currently faced by modellers and model developers in China; (ii) discuss some of the problems in using hydraulic models to simulate water distribution networks; and (iii) propose some new directions in water distribution research.  
 
Computing the BrauerManin obstruction  
Martin Bright (Bristol)  
1 Nov 2007  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Delay dynamics in semiconductor laser systems  
Vicky Crockett and Hartmut Erzgräber (University of Exeter)  
26 Oct 2007  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
Vicky Crockett Lasers with optical feedback can exhibit a wide range of complicated dynamics which can be useful or problematic depending on the desired application. In either case we need to know how to understand laser instabilities to achieve and control the desired type of dynamics. Much work has been done on a laser with little light reflected back in from a distant external mirror, modeled with delay differential equations. For a laser with a nearby external mirror and a large amount of reflected light, the composite cavity model is more appropriate. In such an approach, the system is modeled by ordinary differential equations coupled to a set of algebraic equations for the modes. The mode equations are dependent on the coupling mirror transmission, , and optical length difference between the laser and external cavity, dL^{o}. Bifurcation analysis is used to find regions of stable and chaotic dynamics on the plane of (T,dL). Hartmut Erzgräber Mathematical modeling and understanding the dynamics of coupled laser devices is of importance for many modern laser applications and holds various interesting problems for fundamental research. In the weak coupling approach a laser coupled to a filter can be modeled by delaydifferential equation, which has an infinite dimensional phase space. We will present a comprehensive bifurcation analysis with respect to the relevant parameters. This reveals several codimensiontwo points as organizing centers. The calculated bifurcation diagrams show qualitative agreement with experiments.  
 
New Approaches to Adaptive Water Management Under Uncertainty (NeWater)  
Raziyeh Farmani (University of Exeter)  
25 Oct 2007  Harrison 170 Tuesday 2pm  Informatics RI 
In this talk an introduction will be given to the NeWater project as an Integrated Project (IP) funded by European Commission (EC) under sixth Framework Programme (FP6). This will be followed by introduction to adaptive water resources management. The need for transition from prevailing water management regimes towards adaptive regimes of water facing climate, global and socioeconomic boundary conditions changes will be highlighted. Finally, the role of the tools in facilitating these processes will be discussed and some real applications will be presented.  
 
Hodge structures on homotopy groups  
Jonathan Pridham (Cambridge)  
25 Oct 2007  Harrison 106 Thursday 3pm  Pure Mathematics 
 
The persistence of disease in an SIR model with selfregulation and seasonal birth rate  
Ben Mestel (Open University)  
22 Oct 2007  Harrison 209 Monday 2pm  Applied Mathematics 
 
Modelling the Atmosphere  
Dan Holdaway and James Kent (University of Exeter)  
19 Oct 2007  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
This seminar will consist of two twenty minute talks on numerically modelling the atmosphere. Numerical solutions to the Governing Equations cannot resolve all relevant scales. Processes that are larger than the grid length can be included in the model, however there are many processes that occur on a subgrid level. These subgrid process can interact with the resolved scale processes and affect the large scale flow. The large scale quantities can be solved by the numerical method, while the small subgrid scale processes need to be parametrized. Numerical Methods for Weather and Climate Models. Subgrid Models (SGM) can be added to the numerical scheme to act as the effect of the subgrid processes. All numerical schemes contain errors. If these errors equal the effect of the subgrid processes then there is no need for an explicit SGM. The numerical errors associated with the numerical scheme solving the resolved scale equations could provide an implicit subgrid model for the unresolved scales. Physics Dynamics Coupling. Proper coupling between the SGMs and the resolvable dynamics is key in obtaining accurate weather and climate forecasts. By examining the normal modes of the solutions, the spatial aspects of the coupled system are examined. Questions of particular interest are, what choice of thermodynamic variable works best? What choice of vertical staggering works best? What are the effects of nonuniform grid spacing?  
 
Water Resources Modelling Tools  The ODYSSEUS Project  
Evangelos Rozos (University of Exeter)  
18 Oct 2007  Harrison 170 Tuesday 2pm  Informatics RI 
The subject of the “ODYSSEUS” project was the development of an integrated system of computing tools, which, in combination with a parallel framework of methodologies and technical specifications, provided an infrastructure suitable for a rational and sustainable management of water resource systems at a variety of scales. The research teams that participated to the project implementation derived from the academic field, the private field and the local authorities. The project was funded by the European Development Fund (EDF), the European Social Fund (ESF), the Greek State and Greek private organisations, in the framework of the Operational Project “Competitiveness” of the Third Community Cohesion Fund. The project duration was three years, and begun at July 2003.  
 
A JacquetLanglands correspondence in weight 1  
Lloyd Kilford (Bristol)  
18 Oct 2007  Harrison 106 Thursday 3pm  Pure Mathematics 
We will give a brief introduction to quaternionic modular forms, and present the results of explicit computations relating quaternionic and classical modular forms of weight 1 (using a form of the JacquetLanglands correspondence). This is joint work with Kevin Buzzard  
 
The transition to turbulence in confined shear flows  
Ashley Willis (University of Bristol)  
15 Oct 2007  Harrison 209 Monday 2pm  Applied Mathematics 
 
Spatiotemporal code generation with globally coupled oscillators  
John Wordsworth (University of Exeter)  
12 Oct 2007  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
For systems of globally coupled phase oscillators it is possible to find attractors that form symmetrical and robust heteroclinic networks. By detuning the natural frequencies of the oscillators it is then possible to break the symmetry of these networks. These dynamics can then be used to generate a spatiotemporal code from the input that has been fed into the system by means of detuning and this code can be used to classify the input accordingly.  
 
Tailoring composite material structures at different lengthscales  
HuaXin Peng (University of Bristol)  
11 Oct 2007  Harrison 209 Thursday 2pm  Advanced Technologies RI 
The conventional approach to the development of discontinuous composites is to pursue a homogeneous distribution of the microsized reinforcements in the form of particles, whiskers or short fibres in the matrix. This has enabled some advantages of composites over unreinforced monolithic materials to be realised to a limited extent by altering volume fraction, size and aspect ratio of the reinforcing phases. However, our recent analysis shows that a homogeneously discrete distribution of the reinforcement inevitably results in a property close to the lower bound of the optimal HashinShtrikeman (HS) lower and upper bounds. Importantly, in principle, there exists a range of material structures that attain all the properties encapsulated by the HS lower and upper bounds. In other words, every point within this encapsulated region corresponds to at least one material structure or geometry. Unfortunately, most of such structures are not known. To identify these material structures required innovative thinking and is of major scientific importance. Two new approaches are proposed to achieve this, namely, (1) tailoring the phase contiguity at the Microscale, and (2) tailoring the phase spatial distribution at the Mesoscale. This is based on the fact that both our preliminary experimental results and the recently derived contiguity model have shown that a material structure with varying degree of continuity of the reinforcing phase will be more effective for property improvement. We have also shown that composites with a controlled inhomogeneous reinforcement distribution can result in significant property improvement and such composites effectively have a structure with twohierarchies: the mesocomposite contains a reinforcing phase which itself is a conventional microcomposite.  
 
Asset Deterioration, MultiUtility Data and MultiObjective Data Mining  
Dragan Savic (University of Exeter)  
11 Oct 2007  Harrison 170 Tuesday 2pm  Informatics RI 
Physicallybased models derive from first principles (e.g. physical laws) and rely on known variables and parameters. Because these have physical meaning, they also explain the underlying relationships of the system and are thus usually transportable from one system to another as a structural entity, while only the model parameters have to be updated. Datadriven or regressive techniques involve data mining for modelling and one of the major drawbacks of this is that the functional form describing relationships between variables and the numerical parameters is not transportable to other physical systems as is the case with their classical physicallybased counterparts. Aimed at striking a balance, Evolutionary Polynomial Regression (EPR) offers a way to model multiutility data of asset deterioration in order to render model structures transportable across physical systems. EPR is a recently developed hybrid regression method providing symbolic expressions for models and works with formulae based on true or pseudopolynomial expressions, usually in a multiobjective scenario where the best Pareto optimal models (parsimony vs. accuracy) are selected from data in a single case study. This article discusses the improvement of EPR for dealing with multiutility data (multicase study) advances datadriven modelling while achieving a general model structure for asset deterioration prediction across different water and wastewater systems.  
 
Controlling neurons  
Jeffrey Moehlis (University of California, Santa Barbara, USA)  
8 Oct 2007  Harrison 209 Monday 2pm  Applied Mathematics 
The phase response curve (PRC) for a nonlinear oscillator describes the phaseshift of the oscillation due to an impulsive perturbation as a function of the phase at which the perturbation occurs. We consider how knowledge of the PRC for a neuron can be used to determine external currents which control the time at which the neuron fires. We first use variational methods to determine the optimal currents that elicit spikes at a desired time, showing that there is a unique current that minimizes a squareintegral measure of its amplitude. For intrinsically oscillatory models, we further demonstrate that the form and scaling of this current is determined by the model's PRC. We then propose a novel feedback control mechanism which allows one to control the phase of an oscillation, assuming only that the PRC is known and that a onceperperiod marker event, such as the time at which a neuron fires, can be detected. This work represents a first step toward feedbackbased treatment of ailments such as Parkinson's disease by using electrical deep brain stimulation, in which current is injected into the appropriate brain region to try to desynchronize pathologically synchronized neurons.  
 
Two Stochastic Approaches for Benchmarking Urban Water Systems  
Michael Möderl (University of Innsbruck)  
4 Oct 2007  Harrison 170 Tuesday 2pm  Informatics RI 
A traditional procedure for performance evaluation of systems is to test approaches and methodologies on one or more case studies. However, it is well known that the investigation of real case studies is a tedious task. Moreover, due to the limited amount of case studies available it is not certain that all aspects of a problem can be covered in such procedure. With increasing computer power an alternative methodology has emerged, that is the investigation of a multitude of virtual case studies by means of a stochastic consideration of the overall performance. Within the frame of this approach we develop here a Modular Design System for water distribution systems and we will develop and Case Study Generator for urban drainage systems. With the algorithmic application of such tools it is possible to create a variety of different virtual case studies. Additionally the benchmark of the virtual case studies is shown by an application example, where 2,280 different water distribution systems are evaluated.  
 
The dynamics of the North Atlantic Oscillation and Annular Modes  
Edwin Gerber (Columbia University, USA)  
24 Sep 2007  Harrison 209 Monday 2pm  Applied Mathematics 
The North Atlantic Oscillation (NAO) and Annular Modes are the dominant patterns of intraseasonal variability in the extratropical atmosphere. The NAO in particular characterizes a significant fraction of the wintertime variability in Eastern North America and Europe, and has been recognized in some form since the eighteenth century. I'll begin with a simple model based on random walks to explain why these patterns of variability always dominate statistical analyses of the extratropical circulation. I'll then move to a more realistic model, a dry general circulation model of the atmosphere, to probe the dynamics of the variability. Annular Mode and NAOlike patterns are created with the addition of idealized topography and heating anomalies approximating landsea contrast. We find that the NAO arises from the confluence of topographic and thermal forcing, and is best understood in terms of the eddy life cycle. We also find a parameter sensitive coupling between eddies and the largescale flow that extends the persistence of the variability on timescales of 10100 days. The feedback loop, however, is very sensitive to zonal asymmetries. This sensitivity is explored with a coupled oscillator model to illustrate the impact of standing waves on the eddymean flow feedback.  
 
THE AMETRICS STORY, sub Angstrom distance measurement  
Peter Armitage (SECaM)  
17 Sep 2007  Harrison 170 Thursday None  Advanced Technologies RI (Internal) 
The story of an emerging new technology is presented. Starting from the initial invention of a subangstrom distance measuring device built in a persons living room, to its evaluation and testing at Exeter University and at the National Physical Laboratory in London, together with its subsequent exploitation in the USA. In addition to the technology, the presentation includes the human and business factors and obstacles faced by Inventors that develop revolutionary new technology. The presentation ends with a discussion about possible applications for the device, such as in Metrology (indentation creep), Meteorology (micro air pressure measurements), Geophysics (Earth tide and seismic sensors) and Astrophysics (Quantum gravity wave detection).  
 
Development of Scaffolds and Bioreactors for Tissue Engineering and Stem Cell Bioprocessing  
Julian Chaudhuri (University of Bath)  
13 Sep 2007  Harrison XAT Conference Room (121) Thursday 2pm  Advanced Technologies RI 
Mass transfer limitations of tissue engineering scaffolds are currently hindering the development of threedimensional, clinically viable, tissue engineered constructs. In our laboratory we are investigating routes to improve the formation of viable tissue constructs. This presentation will describe our interests in developing both novel scaffolds and bioreactors, to support cell culture and improve nutrient transport to the proliferating cells. We are also using similar approaches to improve the handling and bioprocessing of stem cell populations.  
 
Global transient behaviour: basins of attraction in experimental nonlinear dynamics  
Lawrie Virgin (Duke University, USA)  
13 Sep 2007  Harrison 170 Thursday 2pm  Applied Mathematics 
 
Periodicity and recurrence in a map with two halfplanes  
Arek Goetz (San Francisco State University)  
7 Aug 2007  Harrison 004 Tuesday 2pm  Applied Mathematics 
 
Bridging the Gap  Skeletal Regneration using mesenchymal populations  an interdisciplinary approach  
Prof. Richard O C Oreffo (University of Southampton)  
26 Jul 2007  Harrison 107 Thursday 2:30  Advanced Technologies RI 
Given the demographic challenges of an ageing population combined with rising patient expectation and the growing emphasis placed on cost containment by healthcare providers, economic regenerative medicine approaches for skeletal regeneration is a major clinical and socioeconomic need. Mesenchymal stem cells or human bone marrow stromal stem cells are defined as multipotent progenitor cells with the ability to generate cartilage, bone, muscle, tendon, ligament and fat. These primitive progenitors exist postnatally and exhibit stem cell characteristics, namely low incidence and extensive renewal potential. These properties in combination with their developmental plasticity have generated tremendous interest in the potential use of mesenchymal stem cells to replace damaged tissues. To date, relatively little is known concerning the phenotypic characteristics, whether from a morphological or biochemical standpoint whilst direct in vivo confirmation of the lineage potential and plasticity or interconversion potential that exists of mesenchymal stem cells and osteogenic progenitor cells remains Nevertheless, strategies harnessing tissue engineering approaches offer much promise for skeletal regeneration using mesenchymal populations. Upon isolation of an appropriate progenitor population, repair and reconstruction of bone defects present additional challenges to the orthopaedic, reconstructive and maxillofacial surgeon including an ability to generate a functional microvascular network within engineered constructs to provide oxygen and nutrients that facilitates growth, differentiation, and tissue. The development of a functional vasculature is critical in respect to bone defects which can be extensive. To achieve this goal of skeletal regeneration, it will be necessary to harness the skills set from a variety of disciplines and there will be a need for close interactions between modelers, physical scientists, tissue engineers and clinicians.  
 
A Changing Climate for Prediction  
Peter Cox (University of Exeter)  
20 Jul 2007  Harrison 254 Friday 12 noon  Applied Mathematics (Internal) 
Standard climate model projections, which have shown the significance of global warming, must be redesigned to inform climate change adaptation and mitigation policy. In this seminar, Peter Cox explains the modelling that informed his & David Stephenson's paper in "Science" of 13.7.07, and invites discussion on climate prediction as an initial value problem.  
 
Laser Assisted Manufacturing  
Prof. Lin Li (University of Manchester)  
12 Jul 2007  Harrison 209 Thursday 2pm  Advanced Technologies RI 
This presentation outlines some of the research work carried out by staff and students in the Laser Processing Research Centre, The University of Manchester. A focus of the presentation is on the innovative approaches for industrial problems, by “thinking outside the box”. The presentation includes subjects on new developments in laser cutting, laser drilling, laser assisted surface engineering, laser micro/nano manufacturing and hybrid lasernonlaser manufacturing technology development. It is hope the that presentation will inspire young engineers and researchers to innovative approaches for practical problems and an interest in high power laser engineering.  
 
Engineering Civilisation from the Shadows  
ICE  Institute of Civil Engineers  South West (6th Brunel International Lecture)  
11 Jul 2007  Royal Clarence Hotel  Wednesday 6pm  Informatics RI 
This lecture will examine world poverty and climate change in the 21st century, focusing on the role of engineering in addressing these challenges in relation to the Millennium Development Goals. The lecture is free to attend but it is necessary to register attendance. ** Places are limited, so register early to avoid disappointment ** Contact Barbara Davey, Regional Administrator: ICE South West  
 
The seasonal cycle of gravity wave drag in the middle atmosphere estimated by an assimilation technique  
Manuel Pulido (UNNE, Corrientes, Argentina)  
26 Jun 2007  Harrison 209 Tuesday 2pm  Applied Mathematics 
11th TAYLOR AND FRANCIS sponsored lecture. T&F are publishers of the Journal Geophysical and Astrophysical Fluid Dynamics// A novel technique to estimate gravity wave drag from global scale analyses will be presented. It is based on the principles of fourdimensional variational data assimilation using a dynamical model of the middle atmosphere and its adjoint. The control variables are solely the horizontal components of gravity wave drag so that the minimum of the cost function that measures the differences between model states and observations gives the optimum gravity wave drag.// The assimilation technique is applied to estimate gravity wave drag using Met Office analyses as the initial conditions and the observations for the year 2002. The seasonal variations of the oneyear gravity wave drag estimation will be presented and analysed. Vertical variations in the sign and pattern of the estimated drag suggest filtering of the gravity wave spectrum by the background flow.  
 
Wild ramification in extraspecial extensions  
Griff Elder (Virginia Tech / University of Nebraska at Omaha)  
21 Jun 2007  Harrison 106 Thursday 2pm  Pure Mathematics 
It was observed, with J. Hooper, that sharp lower bounds for the largest ramification break number in quaternion extensions of dyadic local number fields depend upon the refined ramification filtration, as defined with N. Byott. Moreover, quaternion counterexamples to the conclusion of HasseArf require that this refined filtration be extreme in two different ways. In this talk, we will extend these results to a more general class of nonabelian extensions that includes extraspecial extensions. To keep complications to a minimum, we will work over characteristic $p$ local fields.  
 
Introduction to the new Nature Geosciences Journal  
Heike Langenberg (Editor of Nature Geosciences)  
19 Jun 2007  Harrison 209 Tuesday 12pm  Applied Mathematics 
 
Wealth without money  
Dr. Adrian Bowyer (Bath Univeristy)  
14 Jun 2007  Harrison 209 Thursday 2pm  Advanced Technologies RI 
Look at your computer setup. Imagine if you hooked up a 3D printer. Instead of printing on bits of paper this 3D printer makes real, robust, mechanical parts. To give you an idea of how robust these parts are think of Lego bricks and you're in the right area. You could make lots of useful stuff, but interestingly you could also make most of the parts to make another 3D printer. That would be a machine that could copy itself. This talk will be abut RepRap  the Replicating Rapidprototyper. This 3D printer will make components using FDM Rapid Prototyping, which builds the component up in layers of plastic. This technology already exists, but the cheapest commercial machine would set you back Ł15,000. And it isn't even designed so that it can make itself. So what the RepRap team are doing is to develop and to give away the designs for a much cheaper machine with the novel capability of being able to selfcopy (material costs will be about Ł300). We are distributing the RepRap machine entirely free to everyone using opensource  so, if you have one, you can make another and give it to a friend...  
 
Forecast verification of extremes: Use of Extreme Value Theory  
Rick Katz (NCAR, Boulder, Colorado, USA)  
11 Jun 2007  Harrison 107 Monday 4pm  Applied Mathematics 
Evaluating the ability of a weather forecasting system to predict extremes should be an important consideration in forecast verification, particularly given the well known societal impacts of extreme events. Yet statistical methods devised for extreme values have only rarely been applied. // I adopt a distributionsoriented approach to forecast verification, making use of the calibrationrefinement factorization of the joint distribution of forecasts and observations. The exceedance of a high (or falling below a low) threshold by the weather variable is modeled by a conditional Poisson distribution, whose rate parameter is expanded as a function of the forecast. Likewise, the excess over a high (or deficit below a low) threshold of the weather variable is modeled by a conditional generalized Pareto distribution, whose scale parameter depends on the forecast. In this way, whether or not there is any skill (or how much skill exists) in forecasting weather extremes corresponds to determining whether or not (or to what extent) using the forecast as a covariate improves the fit (e.g., via a likelihood ratio test). // The proposed method is applied to a set of specialized NWS minimum temperature forecasts and observations at Yakima, WA, USA. Because of the risk of damage to fruit buds from freezing during their development, these forecasts were made available to orchardists each spring.  
 
Unfolding of codimensiontwo grazingsliding bifurcations  
Piotr Kowalczyk (University of Exeter)  
5 Jun 2007  Harrison 209 Wednesday 2pm  Applied Mathematics (Internal) 
 
A new global analysis of precipitation  
Mathew Sapiano (University of Maryland, USA)  
31 May 2007  Harrison 171 Monday 2pm  Applied Mathematics 
Many merged multisource global analyses of precipitation exist, including the Global Precipitation Climatology Project (GPCP) analysis and the CPC Merged Analysis of Precipitation (CMAP). The multisource nature of these datasets allows them to use the best data available to produce the most accurate estimate of precipitation for any given place and time. However, this strength can lead to weaknesses in the form of discontinuities in the longer record, which raise questions regarding their suitability for trend analysis. Additionally, high latitude precipitation is poorly determined in these datasets since the available estimates originate from either gauges (which suffer from problems related to undercatch of solid precipitation) or satellite data (which exhibit large errors at high latitudes due to icecontamination issues). We aim to produce a new global analysis of precipitation using Optimum Interpolation (OI) that will overcome both of these issues by using the relatively long consistent precipitation record (~20 years) from the Defense Meteorological Satellite Program (DMSP) Special Sensor Microwave/Imager (SSM/I) and forecast precipitation from the ERA40 reanalysis. An additional advantage of the OI methodology is its facility in the calculation of errors associated with the analysis, which are needed for most applications. I will start by showing results from an intercomparison of the several commonly used precipitation algorithms for SSM/I. Next I will discuss issues associated with the OI and show some early results from our analysis. Finally, I will describe our plans to extend the analysis back in time by using proxy records tied to the reanalysis precipitation and calibrated by the SSM/I data. Our goal is that this extended record of precipitation will be suitable for the assessment of changes in global precipitation in the latter part of the 20th Century at all latitudes.  
 
Stability of patterns for the complex GinzburgLandau equation  
Jorge Diosdado (CIMAT, Guanajuato, Mexico)  
29 May 2007  Harrison 209 Wednesday 2pm  Applied Mathematics (Internal) 
 
The Design and Rehabilitation of Water Distribution Systems Using the Hierarchical Bayesian Optimisation Algorithm  
Ralph Olsson (UoE)  
25 May 2007  Harrison 209 Friday 12noon  Informatics RI 
The design and rehabilitation of water distribution systems is considered here as a constrained least cost optimisation problem. In the design and rehabilitation of water distribution systems the solution space tends to be vast. This paper uses the hierarchical Bayesian Optimisation Algorithm (hBOA) (Pelikan and Goldberg, 2000) to search the solution space with the aim of decreasing the number of fitness evaluations required for convergence. hBOA is a probabilistic model building genetic algorithm which uses a Bayesian network to model the set of promising solutions in each generation. This network is in turn sampled to generate the offspring to be incorporated into the next generation. hBOA has been shown to solve a number of challenging problems in subquadratic time, that is the number of fitness evaluations required for convergence is of order less than the square of the number of design variables. Since a fitness evaluation requires the solution of a set of hydraulic equations there are significant time benefits to be had by reducing the number of evaluations. hBOA is applied to two sample networks as deterministic, single objective problems; the New York Tunnels problem and the 'Anytown' network. Initial results show hBOA to compare favourably with other evolutionary computation techniques in the literature, both in terms of the proportion of runs in which the best known solution is found and in terms of the number of fitness evaluations required.  
 
Statistics of elliptic curves over finite fields  
ErnstUlrich Gekeler (University of Saarbruecken)  
24 May 2007  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Aspects of feedbacks and forcing in stochastic dynamics  
Stuart Townley (University of Exeter)  
22 May 2007  Harrison 209 Wednesday 2pm  Applied Mathematics (Internal) 
 
On the dynamics and adjustment of the Atlantic thermohaline circulation  
David Marshall (University of Oxford)  
21 May 2007  Harrison 107 Monday 2pm  Applied Mathematics 
 
Imprecise probabilities of climate change: aggregation of fuzzy scenarios and model uncertainties  
Dr. Guangtao Fu (UoE)  
18 May 2007  Harrison 209 Fri 12noon  Informatics RI 
Whilst the majority of the climate research community is now set upon the objective of generating probabilistic predictions of climate change, disconcerting reservations persist. Attempts to construct probability distributions over socioeconomic scenarios are doggedly resisted. Variation between published probability distributions of climate sensitivity attests to incomplete knowledge of the prior distributions of critical parameters in climate models. This presentation addresses these concerns by adopting an imprecise probability approach. We think of socioeconomic scenarios as fuzzy linguistic constructs. Any precise emissions trajectory can be thought of as having a degree of membership in a fuzzy scenario. Rather than attempting to distribute an additive probability measure across scenarios a weaker assumption is adopted in monotonic (but nonadditive) measures. It is demonstrated how fuzzy scenarios can be propagated through a lowdimensional climate model, MAGICC. Fuzzy scenario uncertainties and imprecise probabilistic representation of climate model uncertainties are combined using random set theory to generate lower and upper cumulative probability distributions for Global Mean Temperature. Further, application of this method in a decisionmaking context is demonstrated through flood risk analysis in Thames defence system.  
 
Which overconvergent Hilbert modular forms are classical?  
Shu Sasaki (Imperial College London)  
17 May 2007  Harrison 106 Thursday 3pm  Pure Mathematics 
 
What controls the rate of mixing of passive scalars in smooth flows?  
Peter Haynes (DAMTP, University of Cambridge)  
14 May 2007  Harrison 107 Monday 2pm  Applied Mathematics 
 
Bayesian modelling of time aggregated water pipe bursts with a zeroinflated, nonhomogeneous Poisson process.  
Theodoros Economou (UoE)  
11 May 2007  Harrison 209 Fri 12noon  Informatics RI 
A commonly used approach to modelling recurrent failures is based on a nonhomogeneous Poisson process (NHPP) and requires data on actual failure times. Modelling and predicting bursts in underground water pipes is vital to water companies from both an economic and conservation perspective, but often does not allow for use of a conventional NHPP for two reasons. Firstly, because data is commonly only recorded on numbers of failures over a (relatively long) time period and not on exact failure times. Secondly, because failures are usually only observed in a very small proportion of pipes in the network. This paper proposes a model derived from the conventional NHPP which only makes use of numbers of failures in an observed time period and the age of each pipe at the end of this period, but is still able to capture the age deterioration phase of the reliability curve. The model is then further extended to account for censoring and truncation in the data as well as an excess of zeros. Application of this `aggregated' model and its zeroinflated extension are illustrated on a data set involving a network of 532 cement water pipes in Manukau City, Auckland, New Zealand.  
 
BLEEDING COMPOSITES  Autonomic SelfHealing  
Dr. Ian P. Bond (University of Bristol)  
10 May 2007  Harrison 107 Thursday 2pm  Advanced Technologies RI 
Selfhealing is receiving an increasing amount of interest worldwide as a method to autonomously address damage in materials. In particular, for advanced fibre reinforced polymer composite materials it offers an alternative to applying conservative damage tolerant design and potentially could remove the need to perform temporary repairs to damaged structures. The concept of an autonomic selfhealing composite material, where initiation of repair is integral to the material, is now being considered for many engineering applications. This bioinspired concept offers the designer an ability to incorporate secondary functional materials capable of counteracting service degradation whilst still achieving the primary, usually structural, requirement. Most materials in nature are themselves selfhealing composite materials. This seminar reviews the various selfhealing technologies currently being developed for fibre reinforced polymeric composite materials, most of which are bioinspired. The most recent selfhealing work has attempted to mimic natural healing using more detailed study of natural processes. The presentation will also discuss work at Bristol to develop selfhealing fibre reinforced composites incorporating resin filled hollow fibres and vascular networks. A perspective on current and future selfhealing approaches will be offered.  
 
On canonical subgroups of abelian varieties  
Payman Kassaei (Kings College London)  
10 May 2007  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Networks that draw networks or honeybees on scent  
Gabor Orosz (University of Exeter)  
8 May 2007  Harrison 209 Wednesday 2pm  Applied Mathematics (Internal) 
 
Evolutionary computationbased metamodelling  a way forward to run thousands of large simulation?  
Dr SoonThiam Khu (UoE)  
4 May 2007  Harrison 209 Fri 1pm  Informatics RI 
Evolutionary algorithms such as genetic algorithms (and other populationbased search algorithms) are increasing used to solve many engineering optimisation problems.Although these algorithms have the distinct advantage of able to find nearglobal solutions relatively fast, the bottleneck of using evolutionary algorithms for realworld optimisation is due to the computational intensive running of the engineering simulation model. The talk will attampt to examine various ways of resolving such a problem while proposing a relatively new method known as evolutionary computationbased metamodelling. This talk should be of interests to all modellers (like myself) being fustrated with long simulation times using GA optimisation. It will also be a great opportunity for computer scientist to share their experience in resolving such problems.  
 
Wittgroups of constructible derived categories  
Jonathan Woolf (Liverpool)  
3 May 2007  Harrison 106 Thursday 3pm  Pure Mathematics 
 
A new asymptotic solution for stellar dynamo  
Dmitry Sokoloff (Moscow State University, Russia)  
30 Apr 2007  Harrison 107 Monday 2pm  Applied Mathematics 
10th TAYLOR AND FRANCIS sponsored lecture. T&F are publishers of the Journal Geophysical and Astrophysical Fluid Dynamics  
 
On the continuous part of codimension 2 algebraic cycles on certain threefolds  
Volodya Guletskii (University of Liverpool)  
26 Apr 2007  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Compressible convection in rapidly rotating spherical shells  
Kirill Kuzanyan (University of Leeds)  
24 Apr 2007  Harrison 209 Wednesday 2pm  Applied Mathematics (Internal) 
 
The dynamics of the Antarctic slope front  
Peter Baines (Quantifying Earth Systems, QUEST, Earth Sciences, University of Bristol)  
23 Apr 2007  Harrison 107 Monday 2pm  Applied Mathematics 
 
Lean Implementation: Challenges, and Future Research Direction  
Dr Kim Hua Tan (Univeristy of Nottingham)  
19 Apr 2007  Harrison 209 Thursday 2pm  Advanced Technologies RI 
A series of case studies have been, and are being, performed, that look at challenges in Lean Implementation. The focus is on understanding current issues to identifying future research direction. Results are presented from four recent studies.  
 
Challenges in the development of "nonpowered, no moving part" technologies for urban water management  
Dr Mike Faram (Hydro International plc)  
5 Apr 2007  Harrison 107 Thursday 2pm  Informatics RI 
Founded in 1980, Hydro International has developed a reputation as being an innovative and forward thinking party within the water management "equipment supply" sector. The company ranks among the top 800 UK R&D spenders overall and among the top 50 "industrial engineering" spenders. The presentation, by the group's Technical Manager, will provide an introduction to the company, focusing in particular on its technologies, many of which make clever use of fluiddynamic or hydraulic principles in their operation. The challenges faced in developing such "simple in form" yet "complex in operation" systems will be discussed. This will consider the use of experimental methods and numerical techniques (including Computational Fluid Dynamics (CFD)) in product development, and the challenges faced in converting the outputs into practical performance prediction and design selection models.  
 
Integrated wastewater asset management for small catchments  
Guo, Yufeng (South West Water)  
30 Mar 2007  Harrison 102 Friday 1pm  Informatics RI 
Advanced asset management of wastewater systems has recently gained increasing support within industry and research. This project presents a decision support tool (DST) to address integrated management of wastewater assets in South West Water, including wastewater treatment works, sewers and wastewater pumping stations. In the DST, a catchment ranking system based on key performance indicators is set up to identify critical catchments. Proactive interventions are suggested with their potential impacts on cost, performance and failure trends. In the end, costeffective maintenance strategies are accommodated, which can be employed into the industry capital maintenance plan and utilised as a part of "business as usual" operational management.  
 
TBA  
Shaun Stevens (EastAnglia)  
29 Mar 2007  Harrison 106 Thursday 3pm  Pure Mathematics 
 
The precessiondriven dynamo in a plane layer  
Paul Roberts (IGPP, UCLA, USA)  
23 Mar 2007  Harrison 107 Friday 2pm  Applied Mathematics 
9th TAYLOR AND FRANCIS sponsored lecture. T&F are publishers of the Journal Geophysical and Astrophysical Fluid Dynamics  
 
Flood Risk Management  
Dr Slobodan Djordjevic (University of Exeter)  
16 Mar 2007  Harrison 102 Friday 1pm  Informatics RI 
Flood Risk Management Research Consortium (FRMRC) is the ongoing research project involving about thirty UK institutions, with total budget in excess of Ł6m. Following an overview of the Consortium and the background of the CWS involvement, outputs from Work Package 6.1 Urban Flooding to date will be presented. Various problems in development of modelling approaches will be discussed and the examples from case studies will be shown. The following topics will be covered: – GISbased tools to support integrated modelling of urban flooding – Interactions between belowground and aboveground systems – Coupled 1D/1D and 1D/2D simulation of urban flooding – Sensitivitybased flood risk attribution Research themes envisaged for the second phase of the Consortium (FRMRC2, which is currently being negotiated with EPSRC and other funders) will be addressed, as well as some other projects that will result from this research in the near future.  
 
Interpolation by vectorvalued analytic functions, with applications to the controllability of linear systems  
Jonathan Partington (University of Leeds)  
15 Mar 2007  Harrison 215 Monday 2pm  Applied Mathematics 
 
TBA  
Ahmed Abbes (Paris)  
15 Mar 2007  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Parametric instability of the helical dynamo  
Marine Peyrot (LEGI, Grenoble)  
13 Mar 2007  Harrison 209 Wednesday 2pm  Applied Mathematics (Internal) 
 
Efficient data assimilation for spatially extended systems: a local ensemble transform Kalman filter  
Brian Hunt (University of Maryland, USA)  
12 Mar 2007  Harrison 107 Monday 4pm  Applied Mathematics 
8th TAYLOR AND FRANCIS sponsored lecture. T&F are publishers of the Journal Geophysical and Astrophysical Fluid Dynamics  
 
Spatial survival modelling and the 2001 UK footandmouth disease epidemic  
Professor Trevor Bailey (UoE)  
9 Mar 2007  Harrison 102 Fri 1pm  Informatics RI 
The potentially large economic impacts of animal disease epidemics have been highlighted in recent years through outbreaks such as footandmouth disease (FMD) in the UK during 2001. This talk reports work from a project with the Veterinary Laboratories Agency (VLA), Weybridge, UK which is concerned with use of survival modelling to develop dynamic spacetime predictions of survivor and hazard functions for individual farm premises as an animal disease epidemic progresses. Such survival analyses could provide powerful insights into the patterns of infection, and assist in optimising various aspects of the operational response activities, such as targeting of `atrisk' premises. The talk will discuss and compare various possible Bayesian model formulations using both real and simulated epidemics and then go on to illustrate how model predictions may be used to refine epidemic control policies  
 
Cohomology of locally analytic representations  
Jan Kohlhaase (Muenster)  
9 Mar 2007  Harrison TBA Friday TBA  Pure Mathematics 
 
Innovative phasechange pigging of difficult topologies  
Professor Joe Quarini (University of Bristol)  
8 Mar 2007  Harrison 107 Thursday 2pm  Advanced Technologies RI 
The brief presentation will introduce the concept of using phase changing slurries to act as pigs. The aims of these pigs are to hydraulically clean ducts and equipment as well as product recover and product separate material within complex processing plant. In its simplest form, this technology uses water with a freezing point depressant to produce a pumpable ice slurry with the attractive rheological property of behaving like a fluid when under dramatic shear gradients and looking more like a solid when shear is reduced. This means that the ‘ice pig’ is able to pass through orifice plates and then expand out to remove debris on the downstream side of the contraction! The ice pig can be used to clean very complicated geometries, including plate heat exchangers. It can be used as a separator between fluid streams as well as to recover fluid in ducts and equipment. Typically, it requires 100 to 1000 volumes of water to achieve the same level of ‘clean’ as one volume of the ice pig. What makes it really attractive is that it can never ever get stuck….it simply melts away. Further, it is environmentally very friendly, as it reduces waste, ameliorates the need for effluent treatment and reduces the amount and potency of harsh cleaning chemicals currently used. The potential beneficiaries include the food manufacturing sector, fine chemical producers, the medical/pharmaceutical industry and the utilities including water and power.  
 
Exactly solvable problems for excitons in two dimensions  
Misha Portnoi (University of Exeter)  
6 Mar 2007  Harrison 209 Wednesday 2pm  Applied Mathematics (Internal) 
 
The dynamics of deep convection and largescale tropical wave motion  
Glenn Shutts (Met office)  
5 Mar 2007  Harrison 107 Monday 2pm  Applied Mathematics 
 
Managing Distribution Retention Time to Improve Water Quality  
Malcolm Brandt (Black and Veatch Ltd)  
1 Mar 2007  Harrison 107 Thursday 2pm  Informatics RI 
When water leaves a treatment works and travels through a distribution system, its quality, with respect to many chemical and biological parameters, will degrade. The quality of the delivered water will be largely influenced by: The quality of treated water supplied into the network; The condition of distribution assets within the network; The retention time within the network. The water industry has focused predominantly on the quality of treated water and the physical condition of distribution assets when improving the quality of water at the customer’s tap. However the quality of the water delivered is also affected by the time the water is retained in the different elements of the distribution network. Retention time is controlled both by the physical characteristics of the system and the operational regime. Physical characteristics such as pipe roughness may change throughout the life of the asset or be modified by rehabilitation. The aim of this research is to demonstrate that water quality within distribution networks can be managed effectively by controlling retention time and to develop practical and pragmatic methodologies for doing so.  
 
On the padic elliptic polylogarithm and the twovariable padic Lfunction for an CMelliptic curve  
Kenichi Bannai (Nagoya/Paris)  
1 Mar 2007  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Transient dynamics  are they just a passing trend or ... ?  
Stuart Townley (University of Exeter)  
27 Feb 2007  Harrison 209 Wednesday 2pm  Applied Mathematics (Internal) 
 
Are the fractal skeletons the explanation for the plankton paradox and the instent restenosis?  
Celso Grebogi (University of Aberdeen)  
26 Feb 2007  Harrison 107 Monday 2pm  Applied Mathematics 
Nature is permeated by phenomena in which active processes, such as chemical reactions and biological interactions, take place in environmental flows. They include the dynamics of growing populations of plankton in the oceans and the evolving distribution of ozone in the polar stratosphere. I will show that if the dynamics of active particles in flows is chaotic, then necessarily the concentration of particles have the observed fractal filamentary structures. These structures, in turn, are the skeletons and the dynamic catalysts of active processes, yielding an unusual singularly enhanced productivity. I will argue that this singular productivity could be the hydrodynamic explanation for the plankton paradox, in which an extremely large number of species are able to coexist, negating the competitive exclusion principle that asserts the survival of only the most perfectly adapted to each limiting resource. I will then suggest that the presence of such fractal skeletons in arterial flow could be the explanation for the eventual restenosis of arteries after a stentassisted angioplasty.  
 
Evolutionary Optimisation for Microsoft Excel  
Josef Bicik (UoE)  
23 Feb 2007  Harrison 102 Fri 1pm  Informatics RI 
The aim of this seminar is to introduce a new tool allowing the use of single and multipleobjective optimisations using genetic algorithms from within Microsoft Excel. The presentation will show the features of the tool and demonstrate them on several optimisation problems. Special attention will be paid to use of the tool in the optimisation of water systems, however it will be shown that it can be integrated with various other simulation packages.  
 
Potentially crystalline representaions and padic representations of GL_2.  
Matthias Strauch (Cambridge)  
23 Feb 2007  Harrison TBA Friday TBA  Pure Mathematics 
 
Simulations of nonlinear porewater convection in spherical shells  
Zhifeng Dai (University of Exeter)  
20 Feb 2007  Harrison 209 Wednesday 2pm  Applied Mathematics (Internal) 
 
Quaternions and particle dynamics in the Euler equations  
John Gibbon (Imperial College London)  
19 Feb 2007  Harrison 107 Monday 2pm  Applied Mathematics 
 
Practical bifurcation analysis of piecewise smooth systems  
Daniel Pagano (University of Bristol)  
15 Feb 2007  Harrison 107 Thursday 2pm  Applied Mathematics 
The lack of smoothness in these systems precludes the application of local analysis tools (so useful in differentiable dynamics) and then, as a consequence, the separation between local and global issues has a fuzzy character, if it actually exists. Therefore, the bifurcation analysis in this context turns out to be cumbersome and specific for each concrete case. We will show how to proceed in order to obtain bifurcation sets in representative families of planar Filippov systems, and comment the difficulties to overcome in nonsolved cases.  
 
On the continuous part of codimension two algebraic cycles on certain threefolds over a field  
Volodya Guletskii (University Of Liverpool)  
15 Feb 2007  Harrison 106 Thursday 3pm  Pure Mathematics 
Let X be a nonsingular projective threefold over a field with resolution of singularities, and let A^2(X) be the group of algebraically trivial codimension 2 algebraic cycles on X modulo rational equivalence with coefficients in Q. Assume X is birationally equivalent to another threefold X' admitting a fibration over a curve whose generic fiber F satisfies the following three conditions: (i) the motive M(F) is finitedimensional, (ii) for ladic etale cohomology H^1(F)=0 and (iii) H^2(F) is spanned by divisors on F. We prove that, provided these three assumptions, the group A^2(X) is weakly representable: there exists a curve Y and a correspondence z from Y to X, such that z induces an epimorphism A^1(Y) > A^2(X), where A^1(Y) is isomorphic to Pic^0(Y) tensored with Q. In particular, the result holds for threefolds birational to threedimensional Del Pezzo fibrations over a curve.  
 
Marginal stability of planetary convection and magnetism  
Sergey Starchenko (IZMIRAN, Troitsk, Russia)  
13 Feb 2007  Harrison 209 Wednesday 2pm  Applied Mathematics (Internal) 
 
Numerical methods for solving electromagnetic problems  
Jun Zou (The Chinese University of Hong Kong)  
12 Feb 2007  Harrison 107 Monday 2pm  Applied Mathematics 
7th TAYLOR AND FRANCIS sponsored lecture. T&F are publishers of the Journal Geophysical and Astrophysical Fluid Dynamics  
 
An Operational Framework for Trading Water Abstraction Permits in England and Wales  
Ana Maria Millan (University of Exeter)  
9 Feb 2007  Harrison 102 Fri 1pm  Informatics RI 
This study aims to show how the use of market forces to allocate water resources can improve the allocation of water resources in England and Wales. At present, there are growing concerns about the availability of water resources in England and Wales to satisfy increasing demands. These derive mainly from traditional consumers, from the requirements of the Water Framework Directive to protect the waterdependent environment, and from the effects of climate change on flow variability and drought frequency. These conditions show the vulnerabilities of the existing allocation system, which in turn, create an opportunity to propose changes.  
 
Development of a Performance Measurement System for JIT Enabled Manufacturing Environment  
Dr Chike Oduoza (Univeristy of Wolverhampton)  
8 Feb 2007  Harrison 107 Thursday 2pm  Advanced Technologies RI 
The quest for performance measurement and improvement in the manufacturing industry has been an important agenda over the last few decades. It forms an integral part of management control systems and it is used to gauge the performance of business enterprises. Performance Measurement Systems (PMS) are most successful when they are integrated with the company mission, vision, values and strategy. Under intensive global competitive pressure, most companies around the world have applied innovative thinking to management and begun to examine technology that can lead to improved manufacturing flexibility. Justintime manufacturing (JIT), and lean manufacturing are thought to be some of the most important performance enhancing management innovations during the last two decades. However, to date, relatively little research has determined what PMS is consistent with the adoption of lean manufacturing systems such as JIT. Empirical research involving the study of JIT consists primarily of case studies of specific organizations, which have implemented JIT philosophy, however there is no methodology for the measurement of success or failure of this technique or the effect of relevant parameters on its successful implementation The aim of this study is to present a methodology for performance measurement in a JIT enabled manufacturing environment and will identify JIT drivers that are key to influencing performance in a typical production environment. Dynamic simulation and modelling, and a variety of management tools will be applied to determine the impact of typical variables such as TQM, line balancing, set up time etc on enterprise productivity and efficiency. The outcome is a model that would serve as a guide to researchers and industry practitioners on the approach to effective JIT implementation.  
 
Dynamo action in a helical pipe  
Leszek Zabielski (Warsaw University of Technology)  
5 Feb 2007  Harrison 107 Monday 2pm  Applied Mathematics 
 
Modelling Pollutant Adsorption: The atomistic view  
Arnaud Marmier (UoE)  
2 Feb 2007  Harrison 102 Fri 1pm  Informatics RI 
Halogenated chemicals have been used as pesticides and generated as by products of industrial, commercial or social activities. Crucial information needed in order to assist stakeholders in developing remediation strategies for land contaminated by these pollutants includes data on how the pollutants move through a contaminated environment and how the pollutants change and degrade with time. Experiments to answer these questions are difficult to perform and require a significant investment of time. Consequently, such experiments are generally limited studies of a few specific molecules interacting with a small number of soil types. Atomic scale computational models provide a method complementary to experiment. They can produce additional information that aids our understanding of the fundamental processes that lead to pollutant mobility. In this communication, I focus on the adsorption of polychlorodibenzopdioxins (PCDDs) and polychlorobiphenyls (PCBs). In order to better understand how these pollutants move through soils I performed calculations at the atomic scale to resolve how they bind to the components of typical soils. The surface chosen is the (001) face of the dioctahedral 2:1 sheet silicate pyrophillite, Al4Si8O20(OH)4. This is a particularly simple example of the family of clay minerals that form a significant fraction of many soil and rock types. I will also discuss the possibilities offered by some eScience tools for highthroughput modelling of this sort.  
 
HANDLING UNCERTAINTY IN REALTIME FLOOD FORECASTING SYSTEMS  
Professor Ian Cluckie (University of Bristol)  
1 Feb 2007  Harrison 107 Thursday 2pm  Informatics RI 
The seminar will focus on the problems of handling uncertainty in complex realtime flood forecasting systems. This will inevitably introduce the use of closely coupled highresolution mesoscale atmospheric models at one end of the scale and quantitative weather radar at the other. Some of the features of coupled models and systems will be introduced in relation to both urban and rural flood forecasting. The seminar will seek to provide an overall briefing on the area with an introduction to some of the exciting developments which are currently underway. This is particularly so in terms of the current efforts to utilise dualpolarisation weather radar technology for operational purposes in the United Kingdom.  
 
Upper triangular technology and the ArfKervaire invariant  
Victor Snaith (University Of Sheffield)  
1 Feb 2007  Harrison 106 Thursday 3pm  Pure Mathematics 
This is a talk about an old topology problem in the theory of the homotopy groups of spheres. I will do my best to make it entertaining for nonspecialists with emphasis on (i) mathematical history and (ii) the simple algebra which Upper Triangular Technology transforms the topology in.  
 
Reduced atmospheric models using dynamically motivated basis functions  
Frank Kwasniok (University of Exeter)  
30 Jan 2007  Harrison 209 Wednesday 2pm  Applied Mathematics (Internal) 
 
Overcoming essential instabilities induced by coupling delay  
Jan Sieber (University of Aberdeen)  
29 Jan 2007  Harrison 107 Monday 2pm  Applied Mathematics 
Realistic tests in mechanical engineering often involve bidirectional realtime coupling between computer simulations and mechanical experiments. If this coupling occurs at a fixed joint then arbitrarily small delays in the coupling can result in an essential instability, that is, the linearization has infinitely many unstable eigenvalues. A general theorem (see, for example, the textbook of Hale/VerduynLunel) implies that this kind of instability is impossible to compensate. We discuss an approach that is potentially able to overcome this difficulty. This is joint work with Yuliya Kyrychko (Bristol).  
 
Nonlinear dynamics of lasers  
Sebastian Wieczorek (University of Exeter)  
23 Jan 2007  Harrison 203 Wednesday 1pm  Applied Mathematics (Internal) 
 
Solitons in photonic crystal fibers  
Dmitry Skryabin (University of Bath)  
22 Jan 2007  Harrison 107 Monday 2pm  Applied Mathematics 
 
Modelling atmospheres  
Beccy Mitchell, Dan Holdaway and James Kent  
19 Jan 2007  Harrison 107 Wednesday 3pm  Applied Mathematics (Internal) 
 
Data inversion in solar radio spectroscopy: application to the flares  
Gregory Fleishman (Ioffe PhysicoTechnical Institute, St. Petersburg, Russia)  
16 Jan 2007  Harrison 107 Wednesday 1pm  Applied Mathematics (Internal) 
 
Design of parametrically forced patterns  
Alastair Rucklidge (University of Leeds)  
15 Jan 2007  Harrison 170 Monday 2pm  Applied Mathematics 
 
Some dynamical systems without ergodicity  
Peter Ashwin (University of Exeter)  
9 Jan 2007  Harrison 107 Wednesday 1pm  Applied Mathematics (Internal) 
 
Equationfree modeling of inelastic collapse  
Mark Muldoon (University of Manchester)  
8 Jan 2007  Harrison 107 Monday 2pm  Applied Mathematics 
A hard sphere gas whose particles collide inelastically lacks a straightforward hydrodynamic limit and its evolution is poorly described by PDEs. Such gasses undergo a socalled "inelastic collapse", after which most particles are confined to slowmoving, highdensity clusters. Here we apply the recent, "equationfree" methods of Kevrekides and collaboratorswhich combine short bursts of stochastic simulation with Eulerlike time steppingto a prototypical example of inelastic collapse, a onedimensional gas originally studied by Du, Li and Kadanoff.  
 
Modelling of contaminant transport in soils  
Mohammed AlNajjar (University of Exeter)  
15 Dec 2006  Harrison 102 Friday 1pm  Informatics RI 
The movement of contaminants through soils to the groundwater is a major cause of degradation of water resources. In many cases, serious human and stock health implications are associated with this form of pollution. In this presentation, the development and validation of a numerical model for simulation of the flow of water and air, heat transfer and contaminant transport through unsaturated soils will be presented. All the major mechanisms and phenomena controlling transport of contaminants in soils (including advection, dispersion, diffusion, adsorption (under equilibrium and nonequilibrium conditions), chemical reactions and the effect of mobile and immobile domains on transport of contaminants in the soil) have been considered in the model. The mathematical framework and the numerical implementation of the model will be presented and described. The validation of the model will be presented by application to several experiments on contaminant transport in soils from the literature. The application of the model to some case studies will then be presented and discussed.  
 
Simulated annealing and greedy search for multiobjective optimisation  
Dr Richard Everson (University of Exeter)  
8 Dec 2006  Harrison 209 Friday 1pm  Informatics RI 
Evolutionary optimisation algorithms can be broadly categorised by the search techniques used. One such categorisation can be made upon the acceptance criteria for solutions within the algorithm; two popular criteria are to allow only greedy searching (to discard solutions which are not an improvement over previous solutions) and to retain new solutions by MetropolisHastings sampling (as used in simulated annealing). Another categorisation can be made comparing algorithms which sequentially optimise a single solution and those which consider a set of solutions for optimisation. In this seminar we introduce a new multiobjective simulated nnealing technique and illustrate the effect upon convergence of combinations of greedy searching, searching with an annealing schedule, sequential optimisation of a single solution and optimisation of a set of solutions. Apparently greedy strategies are found to be remarkably effective for many problems and we discuss the types of multiobjective problem that will prevent convergence of greedy optimisers.  
 
Solar differential rotation: a new proposal for the tachocline  
Michael McIntyre (DAMTP, University of Cambridge)  
4 Dec 2006  Harrison 107 Monday 2pm  Applied Mathematics 
 
On McRae's Invariant  
Prof Peter Vamos (University Of Exeter)  
4 Dec 2006  Harrison 209 Monday 3pm  Pure Mathematics (Internal) 
 
Fuzzy multiobjective optimisation for WDS  
Dr Lydia VamvakeridouLyroudia (University of Exeter)  
1 Dec 2006  Harrison 102 Fri 1pm  Informatics RI 
This seminar presents the application of fuzzy reasoning, combined with hierarchical multiobjective optimisation for the design of water distribution networks, using genetic algorithms. The problem has been formally structured as a Multilevel Multicriteria Decision Making (MCDM) process with two objectives: cost minimisation and benefits maximisation, resulting in a Pareto tradeoff curve of non dominated solutions. A number of criteria are introduced, individually assessed by fuzzy reasoning. The overall benefits function is a combination (aggregation) of criteria, according to their relative importance and their individual fuzzy assessment. It is obtained through an analytic hierarchy process (AHP), applied directly within the genetic algorithm, using an original mathematical approach. The decision maker enters data and preferences using exclusively linguistic “engineer friendly” definitions and parameters. In this way, the whole design algorithm moves away from strict numerical functions, and acts as a Decision Support System (DSS) for water network design optimisation. The model has been applied to “Anytown”, a wellknown benchmark network, for which results are presented and discussed.  
 
Multiobjective Optimization on Operation of Water Distribution Systems in China  
Professor Liu (Tongji University, China)  
30 Nov 2006  Harrison 107 Thursday 2  Informatics RI 
Traditional research and application of optimal operation of water distribution systems was mostly based on functions of least cost in construction and energy consumption. With the fast urban development and the ageing pipe networks in the world, new targets and tasks have been arising out for water supply companies to deal with, e.g. water pressure satisfaction, water quality uncertainty, water leakage and bursts, environment requirements, etc. In the presentation, extended period simulation models and computer software on optimal operation of water distribution systems were introduced for assessment and forecasting of the hydraulic movements, water quality changes and towards to real time optimal operation and control, based on multiple objectives. The software was applied in several cities in China with valuable results for improving the further planning and operation techniques in water distribution systems. In addition, definitions of optimal diameters and economic leakage in the pipe network will be discussed.  
 
Sediment transport above rippled beds  
Vanesa Magar (University of Plymouth)  
28 Nov 2006  Harrison 107 Wednesday 1pm  Applied Mathematics (Internal) 
 
Quadratic differential forms and (some of) their applications  
Paolo Rapisarda (University of Southampton)  
27 Nov 2006  Harrison 107 Monday 2pm  Applied Mathematics 
Often when dealing with dynamical systems it is important to describe and analyze the interplay of dynamics and functionals of the variables of the system and their derivatives; for example, in the case of linear systems, quadratic functionals are of paramount importance in filtering, estimation, optimal control, etc. Recently, the formalization of these functionals using twovariable polynomial matrices has been proposed by Willems and Trentelman in a framework in which there is no need to use firstorder (i.e. state) representations of a dynamical system as it is customary to do, and one can work with descriptions of the dynamics in terms of systems of higherorder differential equations. In this talk the basic features and some applications of the calculus of these socalled quadratic differential forms are presented.  
 
Discolouration of water distribution networks  
Dr Jan Vreeburg (KIWA (Netherlands))  
24 Nov 2006  Harrison 102 Fri 1pm  Informatics RI 
Discolouration is the single most important reason for customers to complain at their water company about the water quality. Traditionally discoloured water is assumed to be the result of corrosion of unlined cast iron pipes. In the Netherlands (and also elsewhere) however the problem also exists in completely plastic or cementitious pipes so the corrosion cannot be the single cause. In the last decade a lot of research has been done to the nature and cause of discoloured water that resulted in new knowledge and new approaches. Managing discoloured water in a network demands a multiangle approach. In the Netherlands a three stage approach has been developed based on an understanding of the theory of particles in the network. Remedial actions are aimed at hydraulically controlling the accumulation of particles. The results of this approach are comprehensive guidelines for cleaning networks and designing of self cleansing networks. Continuing research in the Netherlands is now concentrating on the challenge of improving the water quality at the treatment to prevent to loading of the network and in that way try to get a proactive solution instead of the reactive measures as cleaning the network. The aim of the lecture is to demonstrate the new knowledge and analysis techniques and try to translate this into practical guidelines and new additional research challenges for the typical UK situation.  
 
High Productivity Welding for the Trans Alaska Gas Pipeline  
Professor Stewart Williams (Cranfield University)  
23 Nov 2006  Harrison 215 Thursday 2pm  Advanced Technologies RI 
Installation of new pipelines is predicted to grow at a rapid rate over the next twenty years, due in part to the increase use worldwide of combined cycle power generation plant using natural gas as fuel. The need to construct large diameter pipelines over long distances has led to an increased demand to improve the productivity of pipeline girth welding. The Welding Engineering Research Centre (WERC) at Cranfield University has been researching into to this application for several with the work split into three phases: Phase 1 – High efficiency automated dual tandem GMA (CAPS) for improved productivity in the fill passes (4 instead of 16) Phase 2 – Application to very high strength steel to reduce the pipe wall thickness from 25mm to 20mm (and therefore material costs (500,00 tonnes less)) Phase 3 – Fibre laser or hybrid fibre laser welding of the root pass – higher speeds. The talk will describe how gas pipelines are manufactured, provide a brief history of pipeline welding, and describe how the first two phases have implemented along with the current research into phase three. The talk will be preceded by a brief introduction to Cranfield University and the current research programme of the WERC.  
 
The effect of mantle conductivity on the superrotating jets near the liquid core surface  
Konrad Bajer (Warsaw University, Poland)  
23 Nov 2006  Harrison 107 Thursday 2pm  Applied Mathematics 
 
Arithmetic conjectures on algebraic cycles  
Prof Andreas Langer (University Of Exeter)  
20 Nov 2006  Harrison 209 Monday 3pm  Pure Mathematics (Internal) 
 
Translating conjunctive water management from concept to practice in mature irrigation systems  
Imogen Fullagar (CSIRO, Australia)  
17 Nov 2006  Harrison 102 Fri 1pm  Informatics RI 
Environmental and production demand for water are increasing interest in realising system efficiencies of groundwater and surface water. This is difficult in mature irrigation systems because management regimes tend to separate groundwater and surface water responsibilities and accounting. Ms Fullagar's research has been to design scoping processes to identifying system efficiency opportunities, and deliver these through local (socioeconomic and management) circumstances. The development of these processes has been based primarily on qualitative data from Coleambally, a ricegrowing irrigation area in New South Wales, Australia. Feedback and comment on processes and research method is welcome.  
 
Rapid mixing and other statistical properties of Lorenz attractors  
Mark Holland (University of Exeter)  
14 Nov 2006  Harrison 107 Wednesday 1pm  Applied Mathematics (Internal) 
I will survey the statistical properties of Lorenz maps and Lorenz flows and in particular give details about the mixing properties of the classical Lorenz attractor (work in progress).  
 
Vortex multipoles and vortex quasimodes: the parallels and differences between coherent structures of fluids and plasmas  
Lorena Barba (University of Bristol)  
13 Nov 2006  Harrison 107 Monday 2pm  Applied Mathematics 
A column of electrons surrounded by a conducting wall and confined by a strong magnetic field is an excellent manifestation of twodimensional vortices in an inviscid fluid. The equations governing the drift motion of a magnetized electron column are isomorphic to the Euler equations for incompressible, 2D flow. This isomorphism implies, for example, that surface charge perturbations on the electron column (called diocotron modes) are equivalent to surface waves on vortex columns (called Kelvin waves). In the plasma literature, a quasimode is a vorticity perturbation which is weakly damped, and behaves like it was a single azimuthally propagating wave on the vortex edge. In fluids, a multipole is an arrangement of two or more peaks of vorticity which is compact, coherent and longlived. The topology of quasimodes and multipoles can appear quite similar. But, is there any inherent physical relationship between the core quasimodes, basically explained by wave phenomena, and the hydrodynamic multipoles, which are more readily explained by the nonlinear interaction of vorticity?  
 
Realizable Galois Module Classes for some Nonabelian Extensions  
Dr Nigel Byott (University Of Exeter)  
13 Nov 2006  Harrison 209 Monday 3pm  Pure Mathematics (Internal) 
 
Datadriven Approach to Asset Deterioration Modelling.  
Prof Dragan Savic (University of Exeter)  
10 Nov 2006  Harrison 102 Fri 1pm  Informatics RI 
 
Piezoelectric composites: Properties and applications  
Chris Bowen (University of Bath)  
9 Nov 2006  Harrison 107 Thursday 2pm  Advanced Technologies RI 
This presentation will provide an overview of the properties and applications of piezoelectric composites. Porous piezoelectrics ceramics with '33' connectivity will be described for hydrophone applications and the mechanism by which porosity increases the performance of the material for SONAR applications will be discussed. These porous piezoelectrics will also be infiltrated with a conductive phase to create model conductordielectric composites in an attempt to understand the origins of the 'universal dielectric response'; a property observed in many materials. Both modelling and experimental results will be presented.  
 
Bringing mathematical insights to the climate change problem  
Peter Cox (University of Exeter)  
7 Nov 2006  Harrison 106 Wednesday 1pm  Applied Mathematics (Internal) 
 
Analytic invariants associated with a parabolic fixed point in C^2  
Vincent Naudot (University of Warwick)  
6 Nov 2006  Harrison 107 Monday 2pm  Applied Mathematics 
Near a parabolic fixed point 0 in R^2, a real analytic diffeomorhism can be embedded in a smooth autonomous flow. We show that in the complexanalytic case the situation is completely different. We construct 2 analytic invariants with respect to local analytic changes of coordinates. One invariant vanishes for time1 maps of analytic flows but generically not equal to 0.  
 
HopfGalois Module Structure Of Tame Biqaudratic Extensions  
Paul Truman (University Of Exeter)  
6 Nov 2006  Harrison 102 Monday 3pm  Pure Mathematics (Internal) 
 
MultiObjective Optimisation in the Presence of Uncertainty  
Jonathan Fieldsend (University of Exeter)  
3 Nov 2006  Harrison 102 Friday 1pm  Informatics RI 
There has been only limited discussion on the effect of uncertainty and noise in multiobjective optimisation problems and how to deal with it. Here this problem is addressed by assessing the probability of dominance and maintaining an archive of solutions which are, with some known probability, mutually nondominating. Methods are examined for estimating the probability of dominance. These depend crucially on estimating the effective noise variance and a novel method for learning the variance during optimisation is discussed as part of this. Probabilistic domination contours are presented as a method for conveying the confidence that may be placed in objectives that are optimised in the presence of uncertainty.  
 
An efficient phasefield model for polycrystaline grain growth  
Prasad Patnaik (University of Exeter)  
31 Oct 2006  Harrison 106 Wednesday 1pm  Applied Mathematics (Internal) 
 
TBA  
Francesco DiPierro (University of Exeter)  
27 Oct 2006  Harrison 102 Friday 1pm  Informatics RI 
TBA  
 
Slow flow between concentric cones  
Oskar Hall (University of Exeter)  
24 Oct 2006  Harrison 106 Wednesday 1pm  Applied Mathematics (Internal) 
 
The helicity conservation in deltaOmega and alphadeltaOmega and its impact to eleven year solar torsional oscillations  
Valery Pipin (Institute SolarTerrestrial Physics, Irkutsk, Russia)  
23 Oct 2006  Harrison 107 Monday 2pm  Applied Mathematics 
This is the 5th TAYLOR AND FRANCIS sponsored lecture. Taylor and Francis are the publishers of the Journal Geophysical and Astrophysical Fluid Dynamics.  
 
Discolouration in potable water distribution systems  
Dr Joby Boxall (Pennine Water Group)  
20 Oct 2006  Harrison 102 Friday 1pm  Informatics RI 
Discolouration is one of the single biggest causes of water quality related customer complaints received by water supply companies. Hence, water companies wish to be able to predict the occurrence of discolouration events and implement appropriate operational and maintenance strategies to reduce such complaints. However there is a large degree of uncertainty around the processes that lead to discolouration events. This talk will present the development of a modelling approach towards predicting the occurrence of discolouration events and the results of field and laboratory studies undertaken to elucidate discolouration processes and mechanisms. For further background information, see the project web page www.PODDS.co.uk  
 
Improved Methods for the Optimum Design and Operations of Water Distribution Systems  
Prof. Graeme Dandy (University of Adelaide)  
19 Oct 2006  Harrison 170 Tuesday 2pm  Informatics RI 
A water distribution system (WDS) is a very complicated system of reservoirs, tanks, pipes, pumps and valves that supplies water to the population of a city. If the system is working properly, it will provide water on demand at adequate pressures and of a suitable quality. A great deal of research has been carried out into the optimum design and operations of WDS. Evolutionary techniques such as genetic algorithms (GAs) have proven to be extremely useful in solving these large nonlinear optimisation problems. However, GAs have the disadvantage that they may require very long run times to identify nearoptimal solutions. This presentation will provide some background on the development and application of genetic algorithms for optimising the planning, design and operations of WDS. The emphasis will be on the practical applications of this set of techniques to real water supply systems. There will be a discussion of recent developments aimed at producing significant speed up of GAs using metamodeling. Metamodelling works by combining the GA with a simplified (statistical or neural network) model of the system. Excellent results have been achieved at run times that are 100 to 1000 times faster than the GA alone. There will also be a discussion of recent research into the optimisation of water quality in WDS and the consideration of sustainability objectives in WDS.  
 
Asymptotic receptivity and the Parabolized Stability Equation: a combined approach to boundary layer transition  
Matthew Turner (University of Exeter)  
17 Oct 2006  Harrison 106 Wednesday 1pm  Applied Mathematics (Internal) 
 
Spatiotemporal epidemic modelling for public health protection  
Ian Hall (Health Protection Agency: Porton Down)  
16 Oct 2006  Harrison 107 Monday 2pm  Applied Mathematics 
 
Multiobjective optimization of water reuse systems  
Darko Joksimovic (University of Exeter)  
13 Oct 2006  Harrison 102 Friday 1pm  Informatics RI 
This presentation will deal with the recently completed research project  AQUAREC, in which the role of the CWS was to derive design principles for integrated water reuse systems. This was achieved by first developing a simulation and optimisation methodology, incorporating it in a DSS named WTRNet, and applying the developed software on several case studies. Following a brief introduction into the concept of integrated water reuse planning, the DSS methodology will be presented with particular focus on its optimisation component. The presentation will conclude with a discussion of WTRNet application results and possible future work.  
 
TBA  
TBA  
12 Oct 2006  Harrison None Thursday 2pm  Advanced Technologies RI 
 
Regulation of primary photosynthetic processes and problems of ecological monitoring  
Andrei Rubin (Moscow State University)  
10 Oct 2006  Harrison 106 Wednesday 1pm  Applied Mathematics (Internal) 
 
Connections between discrete control theory and numerical methods for ODEs  
Adrian Hill (University of Bath)  
9 Oct 2006  Harrison 107 Monday 2pm  Applied Mathematics 
We write a general linear method for the numerical integration of ODEs as a discrete control system. The positive real lemma, the Ztransform and perturbation methods are used to explore the stability of such numerical methods.  
 
The Battle of the Water Sensor Networks: Multiobjective CrossEntropy Approach  
Gianluca Dorini and Philip Jonkerguow (University of Exeter)  
6 Oct 2006  Harrison 102 Friday 1pm  Informatics RI 
 
What is the Region Occupied by a Set of Points?  
Dr Anthony Galton (University of Exeter)  
5 Oct 2006  Harrison 170 Tuesday 2pm  Informatics RI 
There are many situations in GIScience where it would be useful to be able to assign a region to characterize the space occupied by a set of points. Such a region should represent the location or configuration of the points as an aggregate, abstracting away from the individual points themselves. In this paper, such a region will be called a 'footprint' for the points. We investigate and compare a number of methods for producing such footprints, with respect to nine general criteria. The discussion identifies a number of potential choices and avenues for further research. Finally, we contrast the related research already conducted in this area, highlighting differences between these existing constructs and our 'footprints'.  
 
Numerical Rossby wave propagation on the Cgrid  
John Thuburn (University of Exeter)  
3 Oct 2006  Harrison 106 Wednesday 1pm  Applied Mathematics (Internal) 
 
Decay of correlations for Lorentz gases  
Ian Melbourne (University of Surrey)  
2 Oct 2006  Harrison 107 Monday 2pm  Applied Mathematics 
 
Verifying deterministic forecasts of extreme events  
Chris Ferro (Department of Meteorology, University of Reading)  
25 Sep 2006  Harrison 254 Monday 2pm  Applied Mathematics 
Forecast verification, the practice of assessing forecast quality, is difficult for at least two reasons when the event being forecasted is rare. First, sampling variability of quality measures may be high if only a small number of events has been observed. Second, many quality measures necessarily degenerate to trivial values as events become rarer. These problems will be mitigated by means of a statistical model based on extremevalue theory that quantifies the relationship between observations and forecasts. The model's two parameters can be interpreted as measures of forecast quality that do not degenerate with event rarity. The model also predicts the values of standard quality measures as event rarity increases. These model estimates are more efficient than evaluating the measures directly and show that different standard measures can indicate opposing changes in forecast quality as rarity increases. The model will be used to assess forecast quality for some extreme weather events.  
 
The dynamo bifurcation in rotating spheres  
Emmanuel Dormy (Ecole Normale Superieure, Paris)  
22 Sep 2006  Harrison 170 Friday 2pm  Applied Mathematics 
This is the 4th TAYLOR AND FRANCIS sponsored lecture. Taylor and Francis are the publishers of the Journal Geophysical and Astrophysical Fluid Dynamics.  
 
TBA  
TBA  
14 Sep 2006  Harrison None Thursday 2pm  Advanced Technologies RI 
 
TBA  
TBA  
10 Aug 2006  Harrison None Thursday 2pm  Advanced Technologies RI 
 
TBA  
TBA  
13 Jul 2006  Harrison None Thursday 2pm  Advanced Technologies RI 
 
Feel sick? Follow the money!  
Dr. Dirk Brockmann (MaxPlanckInstitute for Dynamics and SelfOrganization)  
22 Jun 2006  Harrison B74 Thursday 2pm  Applied Mathematics 
In the light of increasing international trade, intensified human
mobility and an imminent influenza A epidemic the knowledge
of dynamical and statistical properties of human travel is of
fundamental importance. A quantitative assessment of these properties
on geographical scales still remains elusive and the assumption
that humans disperse diffusively still prevails in models. In 1998 Hank Eskin invented the internet game wheresgeorge.com, an online bill tracking system. The idea behind the game is simple. Users can register at the website, mark individual dollar bills, report them to the website, reenter them into circulation and subsequently monitor their geographic dispersal as other users make reports to the website. We have analysed the wheresgeorge.com dataset and used the dispersal of nearly half a million dollar bills as a proxy for human travel. We were thus able to assess the statistical properties of human travel with a high spatiotemporal precision. We found that dispersal is anomalous in two ways. First, the distribution of travelling distances decays as a power law, indicating that trajectories of bank notes are reminiscent of scale free random walks known as LĂ©vy flights. Secondly, the probability of remaining in a small, spatially confined region for a time T is dominated by algebraic tails which attenuate the superdiffusive spread. We were able to show that human travel can be described mathematically on many spatiotemporal scales by a two parameter continuous time random walk model to a surprising accuracy and conclude that human travel on geographical scales is an ambivalent effectively superdiffusive process.  
 
Periodicity in a system of two rotations (joint work with Anthony Quas)  
Prof Arek Goetz (San Francisco State University)  
13 Jun 2006  Harrison 170 Tuesday 12 noon  Applied Mathematics 
 
Piezoelectric composites: Properties and applications  
Dr Chris Bowen (Materials Research Centre, Department of Mechanical Engineering, University of Bath)  
8 Jun 2006  Harrison None Thursday 2pm  Advanced Technologies RI 
This presentation will provide an overview of the properties and applications of piezoelectric composites. Porous piezoelectrics ceramics with '33' connectivity will be described for hydrophone applications and the mechanism by which porosity increases the performance of the material for SONAR applications will be discussed. These porous piezoelectrics will also be infiltrated with a conductive phase to create model conductordielectric composites in an attempt to understand the origins of the 'universal dielectric response'; a property observed in many materials. Both modelling and experimental results will be presented.  
 
An overview of the research activities at IIT Kanpur: Hydrological Modelling  
Dr. Ashu Jain (ITT Kanpur, India)  
1 Jun 2006  Harrison 170 Tuesday 2pm  Informatics RI 
"In this talk I plan to first give a very brief background of the Indian Institutes of Technology (IITs), IIT Kanpur, and the department of civil engineering at IIT Kanpur. The research activities of the Hydraulics and Water Resources Engineering (HWRE) group at IIT Kanpur will be presented. The focus will be on hydrological modelling. Some case studies on water demand modelling and hydrological modelling will be presented. The methods employed include datadriven techniques of Artificial Neural Networks (ANNs) and Genetic Algorithms (GAs). Special issues such as difficulties in ANN training, integration of conceptual and datadriven approaches, etc. will be discussed and the results presented. If the time permits, a case study on the exploration of physical significance in trained ANN hydrologic models will also be presented."  
 
Syntomic cohomology and explicit reciprocity laws  
Hannu Harkonen (University of Cambridge)  
25 May 2006  Harrison 106 Thursday 5pm  Pure Mathematics 
 
Serre's conjectures over totally real fields  
Frazer Jarvis (Sheffield)  
25 May 2006  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Relating forced climate change to natural variability  
Owen KellieSmith  
23 May 2006  Harrison 106 Wednesday 12 noon  Applied Mathematics (Internal) 
Link to slides  
 
Research in the Computer Graphics and Interactive Systems Laboratory at the Technical University of ClujNapoca in Romania  
Professor Dorian Gorgan (Technical University of ClujNapoca)  
23 May 2006  Harrison 170 Tuesday 2pm  Informatics RI 
 Satellite image processing on the Grid structures (MEDIOGRID project)  Location based services  Graphical modelling and simulation of 3D textile surfaces  Pen based annotation in 2D and 3D graphical applications  
 
Counting HopfGalois Structures  
Nigel Byott (University Of Exeter)  
22 May 2006  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
A conjectural relative fixed point formula  
Damian Roessler (Paris)  
18 May 2006  Harrison 106 Thursday 3pm  Pure Mathematics 
 
The validity of Boussinesq and anelastic equation sets in convecting atmospheres: A normal mode analysis  
Rebecca Mitchell (Exeter)  
16 May 2006  Harrison LT6 Wednesday 12 noon  Applied Mathematics (Internal) 
 
The sheaf of overconvergent Witt Vectors  
Prof Andreas Langer (University Of Exeter)  
15 May 2006  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Near Infrared Optical Tomography for the detection of breast cancer  
Dr Hamid Dehghani (School of Physics)  
11 May 2006  Harrison None Thursday 2pm  Advanced Technologies RI 
 
Rigid syntomic cohomology with coefficients and applications  
Kenichi Bannai (Paris)  
11 May 2006  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Delay induced dynamics of a nonlinear transmission line oscillator model  
David Barton (Bristol Centre for Applied Nonlinear Mathematics, University of Bristol)  
9 May 2006  Harrison LT6 Wednesday 12 noon  Applied Mathematics (Internal) 
 
On the torsion of elliptic curves over sufficiently general function fields  
Andreas Schweizer (University Of Exeter)  
8 May 2006  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Generalized Coleman power series in K2  
Sarah Zerbes (Paris)  
4 May 2006  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Pseudospectra  
Dominic McCarthy (UIniversity of Exeter)  
2 May 2006  Harrison LT6 Wednesday 12 noon  Applied Mathematics (Internal) 
 
Dynamos in flows with cat's eyes  
Andrew D Gilbert (Exeter)  
25 Apr 2006  Harrison LT6 Wednesday 12 noon  Applied Mathematics (Internal) 
 
Multilevel Classifier Systems  Issues, Motivations and Challenges  
Dr Bogdan Gabrys (Bounemouth University)  
6 Apr 2006  Harrison 170 Tuesday 2pm  Informatics RI 
The talk will be concerned with pattern classification problems and in particular the motivations and challenges behind using and designing multiple classifier systems. Starting with an attempt to answer the question of why would one like to combine classifiers we will move to an overview of how to combine them. This will be followed by discussing the issues of majority voting limits and an illustration of the potential enhancement for theoretical error limits when using hierarchical multistage organisations for majority vote based combination systems. The talk will also cover the issues of classifier diversity, classifier selection and will finish with discussions of various practical evolutionary algorithm based implementations of multistage, multilevel and multidimensional selectionfusion models.  
 
Multistability in the Kuramoto model with synaptic plasticity  
Yuri Maistrenko (Institute of Medicin and Virtual Institute of Neuromodulation, Research Centre Jülich)  
28 Mar 2006  Harrison 106 Wednesday 11am  Applied Mathematics (Internal) 
 
A high order WENO finite difference scheme for incompressible fluids and magnetohydrodynamics  
Paul Roberts (IGPP, UCLA, USA)  
27 Mar 2006  Harrison 170 Monday 2pm  Applied Mathematics 
Sponsored by TAYLOR AND FRANCIS, publishers of the Journal Geophysical and Astrophysical Fluid Dynamics  
 
Computed eigenmodes of planar regions  
Nick Trefethen (University of Oxford)  
16 Mar 2006  Harrison 170 Thursday 2pm  Applied Mathematics 
Recently developed numerical methods make possible the highaccuracy computation of eigenmodes of the Laplacian for a variety of "drums" in two dimensions, or as some physicists prefer to call them, problems of "quantum billiards". A number of computed examples will be presented together with a discussion of their implications concerning bound and continuum states, symmetry and degeneracy, eigenvalue avoidance, resonance, localization, eigenvalue optimization, perturbation of eigenvalues and eigenvectors, and the problem of "can one hear the shape of a drum?".  
 
Equivariant vectorbundles on padic symmetric spaces  
Elmar GrosseKloenne (Muenster)  
16 Mar 2006  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Dependence of magnetic field generation by convective flows in a plane layer on the kinematic Prandtl number  
Olga Podvigina (International Institute of Earthquake Prediction Theory and Mathematical Geophysics, Russian Ac.Sci.)  
14 Mar 2006  Harrison LT6 Tuesday 12pm  Applied Mathematics 
Sponsored by TAYLOR AND FRANCIS, publishers of the Journal Geophysical and Astrophysical Fluid Dynamics  
 
Dependence of magnetic field generation by convective flows in a plane layer on the kinematic Prandtl number  
Olga Podvigina (International Institute of Earthquake Prediction Theory and Mathematical Geophysics, Russian Ac.Sci.)  
14 Mar 2006  Harrison LT6 Wednesday 12 noon  Applied Mathematics (Internal) 
Sponsored by TAYLOR AND FRANCIS, publishers of the Journal Geophysical and Astrophysical Fluid Dynamics  
 
PD Structures  
Prof Andreas Langer (University Of Exeter)  
13 Mar 2006  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Weakly nonlinear stability of convective hydromagnetic systems with insignificant alphaeffect in a plane rotating layer to perturbations involving large scales  
Vlad Zheligovsky (International Institute of Earthquake Prediction Theory and Mathematical Geophysics, Russian Ac.Sci.)  
7 Mar 2006  Harrison LT6 Tuesday 12pm  Applied Mathematics 
Sponsored by TAYLOR AND FRANCIS, publishers of the Journal Geophysical and Astrophysical Fluid Dynamics  
 
Weakly nonlinear stability of convective hydromagnetic systems with insignificant alphaeffect in a plane rotating layer to perturbations involving large scales  
Vlad Zheligovsky (International Institute of Earthquake Prediction Theory and Mathematical Geophysics, Russian Ac.Sci.)  
7 Mar 2006  Harrison LT6 Wednesday 12 noon  Applied Mathematics (Internal) 
Sponsored by TAYLOR AND FRANCIS, publishers of the Journal Geophysical and Astrophysical Fluid Dynamics  
 
Prehistoric demography and the spread of the Neolithic: Models based on radiocarbon dates  
Anvar Shukurov (University of Newcastle upon Tyne)  
6 Mar 2006  Harrison 170 Monday 2pm  Applied Mathematics 
 
The Ring Of WittVectors  
Prof Andreas Langer (Universty of Exeter)  
6 Mar 2006  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
The dynamincs of coupled phase oscillators  
John Wordsworth (Exeter)  
28 Feb 2006  Harrison LT6 Wednesday 12 noon  Applied Mathematics (Internal) 
 
Bifurcation and nonuniqueness of exact NavierStokes solutions: Is it consistent to neglect farfield boundaries?  
Rich Hewitt (University of Manchester)  
27 Feb 2006  Harrison 170 Monday 2pm  Applied Mathematics 
 
The onset of almost adiabatic planetary convection  
Sergey Starchenko (Rybinsk State AvianTechnical Academy)  
23 Feb 2006  Harrison 170 Thursday 2pm  Applied Mathematics 
 
Galoismodule structure of a cyclic extension: on a result of Miyata  
Nigel Byott (University of Exeter)  
23 Feb 2006  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Galoismodule structure of a cyclic extension: on a result of Miyata  
Nigel Byott (University Of Exeter)  
23 Feb 2006  Laver B74 Thursday 3pm  Pure Mathematics (Internal) 
 
JefferyHamel flow between two cones  
Oscar Hall (Exeter)  
21 Feb 2006  Harrison LT6 Wednesday 12 noon  Applied Mathematics (Internal) 
 
Transport of momentum and particle in hydrodynamic and magnetohydrodynamic turbulence  
Eunjin Kim (University of Sheffield)  
20 Feb 2006  Harrison 170 Monday 2pm  Applied Mathematics 
 
Synchronization of globally coupled chaotic maps: clusters and quasiclusters  
Anastasiya Panchuk (NAS of Ukraine, Kiev)  
16 Feb 2006  Harrison 170 Thursday 2pm  Applied Mathematics 
 
On the power of linear dependences  
Imre Barany (London)  
16 Feb 2006  Harrison 106 Thursday 3pm  Pure Mathematics 
 
What on earth is a Normalized BiConjugate Minimum Residual Gradient Method?  A brief introduction to Krylov subspace methods"  
John Thuburn (Exeter)  
14 Feb 2006  Harrison LT6 Wednesday 12 noon  Applied Mathematics (Internal) 
 
Describing and modeling biofilm mechanics  
Isaac Klapper (Montana State University)  
9 Feb 2006  Harrison 170 Thursday 2pm  Applied Mathematics 
 
Remote Magnetic Sensing of People (Advanced Technologies Research Institute (ATRI) research seminar)  
Professor Des Mapps (Centre of Expertise in Electromagnetic Sensors, University of Plymouth)  
9 Feb 2006  Harrison 203 Thursday 2pm  Engineering 
 
Real K3 surfaces  
V. Nikulin (Liverpool)  
9 Feb 2006  Harrison 106 Thursday 3pm  Pure Mathematics 
Up to deformation, there are three real types of
elliptic curves which depend on the number of real ovals: 0, 1 or 2.
All elliptic curves are hyperelliptic, and their real forms
can be obtained by the double covering of P^1/R ramified in four
points, some of them conjugate. This gives equations of real
elliptic curves.
K3 surfaces give a 2dimensional generalization of elliptic curves. What about similar results for them? This will be the subject of the talk.  
 
Wave Train Solutions in Spherical Couette Flow  
Ed Blockley (Exeter)  
7 Feb 2006  Harrison LT6 Wednesday 12 noon  Applied Mathematics (Internal) 
 
HopfGalois Module Structure of Tame Biquadratic Fields  
Paul Truman (University Of Exeter)  
6 Feb 2006  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Congruence kernels in arithmetic lattices  
Alec Mason (Glasgow)  
2 Feb 2006  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Finitedimensional attractors of randomlyforced PDEs  
David Broomhead (University of Manchester)  
30 Jan 2006  Harrison 170 Monday 2pm  Applied Mathematics 
 
Nonlinear dynamics of warped accretion discs  
Gordon Ogilvie (University of Cambridge)  
23 Jan 2006  Harrison 170 Monday 2pm  Applied Mathematics 
 
Approximate iterative methods for variational data assimilation  
Amos Lawless (University of Reading)  
16 Jan 2006  Harrison 170 Monday 2pm  Applied Mathematics 
 
Green Ceramic Machining: A Topdown Approach to Rapid Prototyping of Ceramics  
Dr Bo Su (Department of Oral and Dental Science, University of Bristol)  
12 Jan 2006  Harrison 203 Thursday 2pm  Engineering 
 
Nucleation of localised 2D patterns  
David Lloyd (University of Surrey)  
9 Jan 2006  Harrison 170 Monday 2pm  Applied Mathematics 
Localised patterns have been observed in a variety of physical experiments from vibrated granular materials to nonlinear optics. We present the results of Umbanhowar et al. Nature 382 (1996) for the vibrated granular material problem and propose a new process for pattern formation and selection in 2dimensions. We demonstrate this new process by taking a toy model, namely the SwiftHohenberg equation. Taking our guidance from known 1D results, we develop analytical and numerical techniques to explore the nucleation of localised patterns in 2D. Finally, I present results showing the rich bifurcation structure of these patterns and suggest avenues for on going research.  
 
Understanding turbulence through the sequenceofbifurcation approach  
Fritz Busse (University of Bayreuth)  
8 Dec 2005  Harrison 170 Thursday 2pm  Applied Mathematics 
 
Rasterbased models for flood inundation: Simple solutions to a complex problem?  
Dr Neil Hunter (School of Geographical Sciences, University of Bristol)  
1 Dec 2005  Harrison 203 Thursday 2pm  Engineering 
 
Polynomial invariants of links, graphs, and matroids  
S Huggett (Plymouth)  
1 Dec 2005  Harrison 106 Thursday 3pm  Pure Mathematics 
We review the relationships between links, graphs, and matroids. In particular, given a planar graph there are two wellestablished methods of generating an alternating link diagram. Switching from one of these methods to the other corresponds in knot theory to tangle insertion in the link diagrams, and in combinatorics to the tensor product of the cycle matroids of the graphs. We show how the Jones and Tutte polynomials behave under these operations.  
 
Heuristic Algorithms in Group Theory  
M. Craven (Exeter)  
24 Nov 2005  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Bifurcations and heterocliniclike oscillations in highway traffic models with reactiontime delay  
Gabor Orosz (University of Exeter)  
22 Nov 2005  Harrison LT6 Tuesday 12 noon  Applied Mathematics (Internal) 
 
Coupled systems: Theory and examples  
Marty Golubitsky (University of Houston)  
21 Nov 2005  Harrison 170 Monday 2pm  Applied Mathematics 
A coupled cell system is a collection of interacting dynamical systems. Coupled cell models assume that the output from each cell is important and that signals from two or more cells can be compared so that patterns of synchrony can emerge. We ask: How much of the qualitative dynamics observed in coupled cells is the product of network architecture and how much depends on the specific equations? The ideas will be illustrated through a series of examples and theorems. One theorem classifies spatiotemporal symmetries of periodic solutions and a second gives necessary and sufficient conditions for synchrony in terms of network architecture.  
 
Convectons  
Edgar Knobloch (University of California, Berkeley)  
17 Nov 2005  Harrison 170 Thursday 2pm  Applied Mathematics 
Recent simulations of binary fluid convection reveal the presence of multiple numerically stable spatially localized steady states we have called 'convectons'. These states consist of a finite number of rolls embedded in a nonconvecting background and are present at supercritical Rayleigh numbers. The convecton length decreases with decreasing Rayleigh number; below a critical Rayleigh number the convectons are replaced by relaxation oscillations in which the steady state is gradually eroded until no rolls are present (the slow phase), whereupon a new steady state regrows from small amplitude (the fast phase) and the process repeats. The SwiftHohenberg equation, both variational and nonvariational) provides much insight into this behaviour. This equation contains several classes of localized steady states whose length grows in a characteristic 'snaking' fashion as they approach spatially periodic states, and the associated dynamics resemble the binary fluid simulations. The origin of the snaking and the stability properties of the associated states will be elucidated, and the results used to shed light on the remarkable complexity of these simple systems.  
 
Climate Sensitivities via a FokkerPlanck Adjoint Approach  
John Thuburn (University of Exeter)  
15 Nov 2005  Harrison LT6 Tuesday 12 noon  Applied Mathematics (Internal) 
 
Stability of magnetic flux tubes subject to external flows  
Antonio Ferriz Mas (Universidad de Vigo, Spain)  
14 Nov 2005  Harrison 170 Monday 2pm  Applied Mathematics 
 
Stark units, Hilbert symbols and Stickelbergerlike ideals at s=1  
D. Salomon (Kings College London)  
10 Nov 2005  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Uncertain Matrix Systems: From Pseudospectra to Kharitonov Theorems.  
Stuart Townley (Universty of Exeter)  
8 Nov 2005  Harrison LT6 Tuesday 12 noon  Applied Mathematics (Internal) 
 
Metric approximations in global weather forecasting  
Andy White (Met. Office)  
7 Nov 2005  Harrison 170 Monday 2pm  Applied Mathematics 
Weather forecasting by national meteorological centres such as the Met Office is guided by the output of numerical models of the atmosphere's motion and thermodynamics. Most centres use models based on the socalled hydrostatic primitive equations, which in a global context make an assumption of shallowness that involves neglect of part of the Coriolis force. Met Office models have been based on more accurate underlying equations since 1992, and on nonhydrostatic equations since 2002. Recent work has identified a hierarchy of consistent approximated equation sets that are at least as accurate as the hydrostatic primitive equations. The hierarchy includes the hydrostatic primitive equations themselves, the Met Office's equation sets, and a nonhydrostatic formulation used by the Canadian Environment Service. An equation set is said to be consistent if it possesses good conservation properties (for energy, angular momentum and potential vorticity) and if it can be directly derived from Lagrange's equations of motion. Four consistent formulations arise as two approximations are made or not made: (a) an assemblage of approximations known collectively as the shallow atmosphere approximation; (b) neglect of the time derivative in the vertical component of the momentum equation. These may be concisely regarded in terms of approximations of metrics  in one case, of metric factors that describe the assumed geometry, in the other case, of the velocity metric that appears in the definition of kinetic energy.  
 
Hydroinformatics Technologies for Urban Water Systems Planning and Management  
Dr Zoran Vojinovic (UNESCOIHE Institute for Water Education (IHEDelft))  
3 Nov 2005  Harrison 203 Thursday 2pm  Engineering 
 
Eulercharacteristics of nearly perfect complexes  
B. Koeck (Southampton)  
3 Nov 2005  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Uncertainty Intervals, Stability and Kharitonovâ€™s Theorem  
Dominic McCarthy (University of Exeter)  
2 Nov 2005  Harrison LT6 Wednesday 12 noon  Applied Mathematics (Internal) 
 
Spatiotemporal chaos in RayleighBenard convection  
Mike Cross (Caltech)  
31 Oct 2005  Harrison 170 Monday 2pm  Applied Mathematics 
 
Solving conics over function fields  
J. Cremona (Nottingham)  
27 Oct 2005  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Uncertain Matrix Systems: From Pseudospectra to Kharitonov Theorems  
Stuart Townley (University of Exeter)  
25 Oct 2005  Harrison LT6 Tuesday 12 noon  Applied Mathematics (Internal) 
 
Twodimensional flows in slowly deforming domains  
Jacques Vanneste (University of Edinburgh)  
24 Oct 2005  Harrison 170 Monday 2pm  Applied Mathematics 
 
Modelling of nucleation kinetics  
Lindsay Greer (University of Cambridge)  
20 Oct 2005  Harrison 170 Thursday 2pm  Applied Mathematics 
Most phase transitions proceed by growth from particular nucleation sites, which either appear sporadically or are predetermined. In recent decades great progress has been made in the quantitative analysis of growth kinetics, but nucleation remains notoriously difficult to model quantitatively. Yet nucleation is important in so many ways: not only in materials (casting of metals, transparency of polymers), but in medicine (CJD, kidney stones), environment (meteorology, crop damage). This presentation will introduce some of the issues in the mechanisms of nucleation, the consequences for how it is modelled and for mathematical techniques. There are, for example, nucleation phenomena that are in general understood, but where the complexity as yet precludes prediction of nucleation rates. Different forms of analysis may be needed at different length scales. Despite the difficulties, recent work shows that there are cases in which sound quantification and prediction are possible. Nucleation is often regarded as an intrinsically stochastic process, yet the recent work focuses on deterministic behaviour.  
 
Shared values of meromorphic functions on compact Riemann surfaces  
A.Schweizer (Exeter)  
13 Oct 2005  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Timestepping methods for linearly stiff systems  
Paul Matthews (University of Nottingham)  
10 Oct 2005  Harrison 170 Monday 2pm  Applied Mathematics 
 
On Tsuzuki's approach to the Crewconjecture  
M.Lederer (Innsbruck)  
6 Oct 2005  Harrison 106 Thursday 3pm  Pure Mathematics 
 
The linked twist map approach to fluid mixing  
Rob Sturman (University of Bristol)  
3 Oct 2005  Harrison 170 Monday 2pm  Applied Mathematics 
 
The analytic structure of Euler flow  
Uriel Frisch (Observatoire de Nice)  
19 Sep 2005  Harrison 170 Monday 2pm  Applied Mathematics 
 
Probabilistic aspects of recurrence in dynamical systems  
Sandro Vaienti (Luminy, Marseille)  
16 Sep 2005  Harrison B74 Friday 2pm  Applied Mathematics 
 
Where Strategic and Evolutionary Stability Depart  A Study of Minimal Diversity Games  
Dieter Balkenborg (Exeter (Economics))  
28 Jun 2005  Harrison 170 Tuesday 3.40pm  Applied Mathematics 
The paper is concerned with the connection between two different approaches to game theory: evolutionary game theory and equilibrium refinement. The literature on learning and evolution studies the evolution of simple forms of adaptive behaviour. It asks, for instance, under which conditions evolutionary selection or learning will in the long run lead to rational behaviour and Nash equilibrium.
In contrast, the literature on refinement presupposes highly rational individuals. Its starting point is the observation that many interesting games have Nash equilibria that are unconvincing as solutions to a game and that additional criteria are needed to refine among them. The most developed notion of equilibrium refinement is the concept of strategically stable sets of Nash equilibria as introduced by Kohlberg and Mertens and as further developed by Mertens. A number of papers indicate a strong connection between evolutionary and strategic stability. Recently De Michelis and Ritzberger have shown for a very general class of dynamics that model evolutionary or learning processes between different populations that an asymptotically stable Nash equilibrium component must contain a strategically stable set if its Euler characteristic is not zero. We ask whether, conversely, a strict equilibrium set containing a Mertens stable set must have nonzero Euler characteristic. We address this question for a special class of games that we call minimal diversity games. In a minimal diversity game each member of a team of I players must independently and simultaneously choose one of the numbers k=1,...,K. Each player gets payoff 1 if all players name the same number and payoff 0 otherwise. Minimal diversity games have two equilibrium components. One consists of an isolated mixed strategy Nash equilibrium where each player takes each choice with equal probability. The other consists of the set of efficient Nash equilibria where at least two players choose different pure strategies. The mixed strategy Nash equilibrium is strategically stable, but not evolutionary stable. The efficient component is shown to be a topological sphere of dimension (I1)*(K1)1. It has hence zero Euler characteristic iff it is odd dimensional, i.e. if I or K is odd. Therefore it contains a strategically stable set if it is an even dimensional sphere. For the cases I=2 and K odd we show that it does not contain a strategically stable set. Closely related (and proved with the same construction) is the fact that for nearby payoff perturbations of the game generically no trajectory of an evolutionary dynamic converges. It is not yet known whether the finding extend to other minimum diversity games with three of more players.  
 
Master equation approach to the study of phase change processes in data storage media  
Konstantin Blyuss (Exeter)  
28 Jun 2005  Harrison 170 Tuesday 4.30pm  Applied Mathematics 
The dynamics of crystallization in phasechange materials is investigated using a master equation approach. We develop a novel model using the thermodynamics of the processes involved. Some partial analytical results are obtained for the isothermal case and for large cluster sizes, but principally numerical simulations are used to investigate the model.  
 
Realtime dynamic substructuring: stability and Hopf bifurcation in a neutral delay differential system  
Yuliya Kyrychko (Bristol)  
28 Jun 2005  Harrison 170 Tuesday 1.30pm  Applied Mathematics 
Realtime dynamic substructuring is a powerful testing method which brings together analytical, numerical and experimental tools for the study of complex structures. It consists of replacing one part of the experimental structure with a numerical model, connected by a transfer system. In order to provide reliable results, the hybrid system has to remain stable during the whole test. One of the problems with the method is the presence of delay due to several technical factors. This delay can lead to destabilization and failure. In this talk we consider a hybrid system, consisting of a pendulum attached to a massspringdamper. The latter is replaced by a numerical model and the transfer system is an actuator. The model we use is a system of two coupled second order neutral delay differential equations. We carry out a stability analysis of the system and identify possible regions of instability and the number of stability switches depending on parameters and delay time. Using the parameters from a real experiment, we perform numerical simulations which confirm our analytical findings, and show regions of periodic and quasiperiodic behaviour.  
 
Robustness tools in ecology  
Stuart Townley (Exeter)  
28 Jun 2005  Harrison 170 Tuesday 2.20pm  Applied Mathematics 
 
Classification of defect ArtinSchreier extensions  
FranzViktor Kuhlmann (Saskatchewan & Newton Inst)  
28 Jun 2005  Harrison 106 Tuesday 10am  Pure Mathematics 
 
Classification of defect ArtinSchreier extensions  
FranzViktor Kuhlmann (Saskatchewan & Newton Inst)  
28 Jun 2005  Harrison 106 Tuesday 10am  Pure Mathematics 
 
Ramification and Galois structure in 1dimensional elementary abelian local extensions  
Griff Elder (University of Nebraska at Omaha)  
24 Jun 2005  Harrison B93 Friday 3pm  Pure Mathematics 
 
TBA  
Professor Mario Alexandre Teles de Figueiredo  
2 Jun 2005  Harrison 254 Tuesday 3pm  Computer Science 
 
THIS SEMINAR HAS BEEN CANCELLED 'Automated feature detection and classification in Solar Feature Catalogues'.  
Dr Valentina Zharkova  
26 May 2005  Harrison 254 Tuesday 3pm  Computer Science 
The searchable Solar Feature Catalogues (SFC) developed using automated pattern recognition techniques from digitized solar images are presented. The techniques were applied for detection of sunspots, active regions,filaments and lineonsight magnetic neutral lines in the automatically standardized full disk solar images in Ca II K1, Ca II K3 and Ha taken at the Meudon Observatory and white light images and magnetograms from SOHO/MDI. The results of automated recognition were verified with the manual synoptic maps and available statistical data that revealed good detection accuracy. Based on the recognized parameters a structured database of the Solar Feature Catalogues was built on a mysql server for every feature and published with various predesigned search pages on the Bradford University web site http://www.cyber.brad.ac.uk/egso/. The SFCs with a coverage of 10 years (19962005) are to be used for the solar feature classification and activity forecast, the first classification attempts will be discussed.  
 
Faltings's strict modules: a characteristic p analogue of classical finite flat group schemes  
Victor Abrashkin (Durham)  
20 May 2005  Harrison 106 Friday 5pm  Pure Mathematics 
 
A conservation of fragility law and its consequences for biochemical network dynamics  
Jorge Gonçalves (Cambridge University)  
19 May 2005  Harrison 170 Thursday 2pm  Applied Mathematics 
Robustness is a defining feature of successful complex systems. In this talk I will describe a fundamental limit on the robustness of complex systems achievable through feedback control. Based on a generic formulation of the control problem, we define /fragility/ in terms of the sensitivity of an output to a disturbance and derive an integral constraint (lowerbound) on the net fragility of a system. Put simply, reducing the sensitivity to disturbances at one range of frequencies by feedback control will necessarily amplify disturbances at other frequencies. For the special case of linear feedback systems, this result reduces to Bode's integral formula. We illustrate the implications of this robustness tradeoff for biological systems, and identify feedforward control and buffering as strategies for ameliorating the tradeoff. Finally, the theory provides an alternate interpretation of Shannon's channel capacity theorem for nonlinear control systems.  
 
Computation without representation, and other mysteries  
Derek Partridge (Department of Computer Science)  
13 May 2005  Harrison 171 Friday 4pm  Computer Science (Internal) 
The talk will cover the necessity for software that is not, and cannot be, faultless, but is, nevertheless, optimal. In particular, the need for inductive software technologies and why it may be impossible to track down known bugs. Then we move on to computations that know when they're wrong (to cope with the inevitable erroneous outputs), and a final generalization into the philosophical notion of accurately approximate computation as an alternative to precisely correct/incorrect computation.  
 
Inaugural Lecture: The mathematical basis for numerical weather and climate models: past successes; future challenges  
John Thuburn (University of Exeter)  
9 May 2005  XFI centre  Monday 6pm  Applied Mathematics 
 
THIS SEMINAR HAS BEEN CANCELLED Using perceptual models to improve fidelity and provide invariance to valumetric scaling for quantization index modulation watermarking  
Professor Ingemar Cox  
5 May 2005  Harrison 254 Tuesday 3pm  Computer Science 
Quanitization index modulation (QIM) is a computationally efficient method of watermarking with side information. This paper proposes two
improvements to the original algorithm.
First, the fixed quantization step size is replaced with an adaptive step size that is determined using Watson's perceptual model. Experimental results on a database of 1000 images illustrate significant improvements in both fidelity and robustness to additive white Gaussian noise. Second, modifying the Watson model such that it scales linearly with valumetric (amplitude) scaling, results in a QIM algorithm that is invariant to valumetric scaling. Experimental results compare this algorithm with both the original QIM and an adaptive QIM and demonstrate superior performance.  
 
URBAN WATER MANAGEMENT IN DEVELOPING COUNTRIES  RESEARCH@WEDC  
Dr V. Vairavamoorthy (Loughborough)  
5 May 2005  Harrison 203 Thursday 2pm  Engineering 
The presentation will cover research currently being undertaken in the area of Hydroinformatics at WEDC, Department of Civil and Building Engineering, Loughborough University. Research is currently being undertaken to develop decision support systems for low and middle income countries in the areas of: water supply management; risk and reliability of water supply systems; watershed models for optimal plans of spatial allocation of water and land resources; hydraulic simulation of irrigation systems using open source technologies like Java and MySQL. The presentation will provide a brief description of two example research projects that attempt to support the United Nations Millennium Development Goals (MDG’S). The MDG’s have set clear targets for reducing poverty, hunger, illiteracy, disease, discrimination against women and environmental degradation by 2015. Progress towards the key MDGs will be accelerated through improved environmental health conditions, in particular access to water and sanitation and environmental sustainability. The two example research projects contribute in a small way to the Target 10 of the MDGs as the first is in relation to improving access to water (quantity) and the second is in relation to improving access to improved water quality. Both research projects involve: development of appropriate technology for the particular problem in the developing country; involve a strong software component; involve a capacity building element. The two example research projects that will be presented will be: Guidelines for “Design of water supply systems operating under water scarcity conditions” –In many countries the availability of water is either inadequate or restricted due to difficulties such as power cuts. An alternative approach to design of these systems has been developed which employs a modified network analysis procedure and utilises formal optimisation techniques to ensure the maximum uniformity in supply. Guidelines for “Water quality risk assessment & management in piped water”  This concerns the risk of contaminant intrusion into water distribution systems (WDS) under extreme conditions (e.g. pipe break, low etc.) which is one of the main reasons for water quality degradation. The presentation will describe the development of IRAWDS, a new and innovative GIS based tool for managing water quality in urban distribution systems in developing countries. The outputs from IRSWDS are a series of risk maps that indicate the risk of contaminant intrusion in the various parts of the water distribution system.  
 
Counting orbits on colourings, flows, and codewords  
Peter Cameron (Queen Mary)  
5 May 2005  Harrison 106 Thursday 3pm  Pure Mathematics 
 
A unifying explanation of the transition to seizure states via a model of Human EEG  
John Terry (Loughborough)  
28 Apr 2005  Harrison 209 Thursday 4pm  Applied Mathematics 
 
Inaugural Lecture  The World of Primes since Fermat  
Professor Andreas Langer (University of Exeter)  
28 Apr 2005  Harrison LT3 Thursday 2pm  Pure Mathematics 
 
Terascale simulation using bytesize pieces  
Lee Margetts (University of Manchester)  
25 Apr 2005  Harrison 170 Monday 2pm  Applied Mathematics 
 
Design Optimization and Stochastic Analysis: Issues of Commercial Software Development  
Professor Vassili Toropov (Altair Engineering Ltd.)  
15 Apr 2005  Harrison H203 Friday 14.00  Engineering 
This talk will be on design optimization and stochastic analysis as seen by Altair Engineering, an international commercial software developer, vendor and consulting company. Examples from its customers will demonstrate how such software tools are used in product development in automotive, aerospace, consumer goods, medical, offshore and other sectors.  
 
Future issues in urban drainage modelling: urban flooding and integrated approaches  
Prof. Theo Schmitt (Technical University of Kaiserslautern)  
24 Mar 2005  Harrison 203 Thursday 2pm  Engineering 
After a short introduction of my group at Kaiserslautern University, I would briefly outline the development of urban drainage modelling and then focus on two specific issues: (1) Modelling of urban flooding has become an important issue elated to the European Standard EN 752 and the flooding frequencies ecommended for urban drainage systems. A detailed approach coupling hydraulic models for surface and sewer flow will be presented. (2) Integrated modelling of the urban wastewater system has been pushed during the last decade to consider all wastewater related sources of pollution load discharged to receiving waters. Aspects of integrated modelling will be illustrated by linking a detailed pollution load model (drainage system) and IWA's Activated Sludge Model (wastewater treatment plant).  
 
The Soft Machines: Computing with the Code of Life  
Martyn Amos (Department of Computer Science)  
18 Mar 2005  Harrison 171 Friday 4pm  Computer Science (Internal) 
Cellular computing is a new, rapidly expanding field of research at the intersection of biology and computer science. It is becoming clear that, in the 21st century, biology will be characterized more often as an information science. The flood of data generated first by the various genome projects, and now by largethroughput gene expression, has led to increasingly fruitful collaborations between biologists, mathematicians and computer scientists. However, until recently, these collaborations have been largely oneway, with biologists taking mathematical expertise and applying it in their own domain. With the onset of molecular and cellular computing, though, flow of information been growing in the reverse direction. Computer scientists are now taking biological systems and modifying them to obtain computing devices. Cells are being reengineered to act as microbial processors, smart sensors, drug delivery systems and many other classes of device. This talk traces the brief history of cellular computing and suggests where its future may lie.  
 
Arithmetic progressions of primes  
Ben Green (Bristol)  
17 Mar 2005  Harrison 106 Thursday 3pm  Pure Mathematics 
Green and Tao recently announced a proof of the existence of arbitrarily long finite arithmetic progressions consisting entirely of primes. This is one of the biggest results in number theory in recent years. Ben Green will be talking about this work today.  
 
On phase transitions in coupled map lattices  
Wolfram Just (Queen Mary University of London)  
14 Mar 2005  Harrison 170 Monday 2pm  Applied Mathematics 
Coupled map lattices are a paradigm for studying fundamental questions in spatially extended dynamical systems. Within this tutorial we focus on qualitative changes of the motion which are intimately related with the limit of large system size. Similar to equilibrium phase transitions, such qualitative changes are an ubiquitous feature of dynamical systems with a large number of degrees of freedom. Within the first part we present an overview and some phenomenological facts of phase transitions in coupled map lattices. The following two parts describe in some details analytical tools which are useful for understanding phase transition behaviour in dynamical systems beyond plain numerical simulations. We explain how coupled map lattices are linked with the canonical equilibrium physics of spin systems when techniques of symbolic dynamics are applied. Using a simple model we explain how coupled map lattices are linked with phase transitions in equilibrium spin models. In the last part we describe an alternative approach in terms of kinetic spin models linking the dynamics of coupled map lattices with equilibrium and nonequilibrium statistical mechanics.  
 
A model for the pure bending of isotropic tubes: localized buckling and the Brazier effect  
Khurram Wadee (University of Exeter)  
14 Mar 2005  Harrison 106 Monday 10am  Applied Mathematics (Internal) 
 
Effect of heat release on the dissipation of scalar fluctuations in turbulent premixed flames  
Dr N. Swaminathan (University of Cambridge)  
10 Mar 2005  Harrison 203 Thursday 2pm  Engineering 
The scalar dissipation rate signifies the local mixing rate and thus plays a vital role in the modelling of reaction rate in turbulent flames. The local mixing rate is influenced by the turbulence, the chemical and the molecular diffusion processes which are strongly coupled in turbulent premixed flames. Thus, the model for the mean scalar dissipation rate, thus the mean reaction rate, should include the contributions of these processes. Earlier models for the scalar dissipation rate includes only a turbulence time scale. In this study, we derive exact transport equations for the instantaneous and the mean scalar dissipation rates. Using these equations, a simple algebraic model for the mean scalar dissipation rate is obtained. This model includes a chemical as well as a turbulence time scale and its prediction compares well with direct numerical simulation results. ReynoldsAveragedNavierStokes calculations of a test flame using the model obtained here show that the contribution of dilatation to local turbulent mixing rate is important to predict the propagation phenomenon in turbulent premixed flames.  
 
Euler characteristics in relative algebraic Kgroups  
Manuel Breuning (Nottingham)  
10 Mar 2005  Harrison 106 Thursday 3pm  Pure Mathematics 
 
The fundamental group scheme in characteristic p and the conjectures of Nori  
Vikram Mehta (Tata Institute, Mumbai)  
10 Mar 2005  Harrison LT321 Thursday 10am  Pure Mathematics 
 
RSS Local Group Meeting Bayesian spatial partition modelling in epidemiological casecontrol studies  
Carmen Fernández (Lancaster University)  
10 Mar 2005  Exeter University Laver, 321 Thurs 2pm  Statistics & Operational Research 
The talk considers developments in the modelling of casecontrol data where each sample individual is associated with a geographical location. A logistic regression framework is used and residual spatial variation is flexibly accommodated via the use of Voronoi tessellations with unknown numbers and locations of tiles. Modifications for matched casecontrol studies are also discussed.  
 
Using a dynamical systems approach to study the dyanmics of model reference adaptive control systems  
David Wagg (University of Bristol)  
7 Mar 2005  Harrison 170 Monday 2pm  Applied Mathematics 
 
Nonlinear dynamo action in hydrodynamic instabilities driven by shear  
Pu Zhang (University of Exeter)  
7 Mar 2005  Harrison 106 Monday 10am  Applied Mathematics (Internal) 
 
How computer science can reveal problems with the standard model of cancer and can identify new models of cancer  
Ajit Narayanan (Department of Computer Science)  
4 Mar 2005  Harrison 171 Friday 4pm  Computer Science (Internal) 
The dominant paradigm of cancer development is
that mutations to a small number of genes transform a
healthy cell into a cancerous cell by blocking normal
pathways or making other pathways hyperactive.
Specific molecular pathways ('subway lines') are claimed to
be responsible for programming these behaviours. My work on
cancer gene expression data does not support this view.
While my own research aim is also to come up with networks and maps of cancer, what distinguishes my approach from the dominant paradigm and its alternatives is that, in my approach, a specific pathway may be normal or cancerous depending on the expression values of genes making up the pathway. We do not need to assume that a cancer pathway is like a tubetrain taking a different and unscheduled route from normal. Instead we can assume that the same route may be used in both normal and cancer cells. What differs is the number of trains passing through each station. It may not even matter that some of these trains are not fully formed trains (i.e. are mutated). What matters is the volume of traffic along the route: a route that is normal one day can become cancerous another day if the volume of traffic along the route changes significantly. If this is right, this will lead to a new view of cancer development and progression that has immediate and very different implications for possible therapeutic intervention and prevention. No knowledge of biology is assumed. The talk will introduce the dominant paradigm of cancer and present some of our work on the alternative, leaving room for discussion and speculation.  
 
Towards an Evolutionary Computation Approach to the Origins of Music  
Dr Eduardo Reck Miranda  
3 Mar 2005  Harrison 254 Tuesday 3pm  Computer Science 
Evolutionary Computation (EC) may have varied applications in Music. This paper introduces three approaches to using EC in Music (namely, engineering,creative and musicological approaches) and discusses examples of representative systems that have been developed within the last decade, with emphasis on more recent and innovative works. We begin by reviewing engineering applications of EC in Music Technology such as Genetic Algorithms and Cellular Automata sound synthesis, followed by an introduction to applications where EC has been used to generate musical compositions. Next, we introduce ongoing research into EC models to study the origins and evolution of music and detail our own research work on modelling the evolution of musical systems in virtual worlds.  
 
The fundamental group of curves in positive characteristic  
Mohamed Saidi (University of Exeter)  
3 Mar 2005  Harrison LT321 Thursday 10am  Pure Mathematics 
 
A simple model of the dynamics of sudden stratospheric warmings  
Gavin Esler (University College London)  
28 Feb 2005  Harrison 170 Monday 2pm  Applied Mathematics 
 
How to compute using globally coupled oscillators  
Jon Borresen (University of Exeter)  
28 Feb 2005  Harrison 106 Monday 10am  Applied Mathematics (Internal) 
 
Bayesian Averaging over Decision Trees  
Vitaly Schetinin (Department of Computer Science)  
25 Feb 2005  Harrison 171 Friday 4pm  Computer Science (Internal) 
Bayesian averaging (BA) over classification models allows analysts to estimate the uncertainty of classification outcomes within prior knowledge. By averaging over ensemble of classification models, the class posterior distribution, e.g. its shape and parameters, can be estimated and used by analysts to judge on the confident intervals. However the standard Bayesian methodology has to average all possible classification models that makes this methodology computationally infeasible for realworld applications.
The feasible way of implementing the BA is the use Markov Chain Monte Carlo (MCMC) technique of random sampling from the posterior distribution. Within the MCMC technique the parameters of classification model are drawn from the given priors. The proposed models are accepted or rejected accordingly to a Bayes rule. When the class posterior distribution becomes stable, the classification models are collected and their classification outcomes are averaged. Regarding to Decision Tree (DT) classification models which provide a tradeoff between the classification accuracy and interpretability, there are three questions which still remain open. The first is the condition under which the Markov Chain can make reversible moves and guarantee that the MCMC can explore DTs with different parameters within the given priors. The second question is how to avoid local minima during the MCMC search. The final third question is how to select a single DT from the DT ensemble which could be used for interpretation. All these three problems will be discussed and the experimental results obtained on some real world data (e. g. the UCI Machine Learning Repository, StatLog, the Trauma data etc) will be presented.  
 
On the padic regulator of varieties over padic fields  
Dr Noriyuki Otsubo (Paris)  
24 Feb 2005  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Purity for pdivisible groups  
Prof Thomas Zink (Bielefeld)  
24 Feb 2005  Harrison 106 Thursday 5pm  Pure Mathematics 
 
Postgraduate Seminar Some investigations in discriminant analysis with mixed variables  
Nor Idayu Mahat (University of Exeter)  
24 Feb 2005  Exeter University Laver, 321 Thurs. 2pm  Statistics & Operational Research 
The location model has been developed for the treatment of mixed categorical and continuous variables in discriminant analysis. In its recent development, Asparoukhov and Krzanowski (2000) suggested estimating the parameters of the location model by using nonparametric smoothing procedures. This approach overcomes some deficiencies in Maximum Likelihood Estimation and Linear Model Estimation. However, the choice of smoothing parameters by maximising the leaveoneout pseudolikelihood function suggested in this approach depends on distributional assumptions This talk will describe how the smoothing parameters can instead be chosen by optimising either the error rate or the Brier score, neither of which make distributional assumptions. Some investigations on other possible smoothing procedures also will be discussed.  
 
Slumping of granular media  
Rich Kerswell (University of Bristol)  
21 Feb 2005  Harrison 170 Monday 2pm  Applied Mathematics 
 
Mixing of passive scalars in Baker's maps  
Andrew Gilbert (University of Exeter)  
21 Feb 2005  Harrison 106 Monday 10am  Applied Mathematics (Internal) 
 
A DominanceBased Mapping from MultiObjective Space for Single Objective Optimisers  
Kevin Smith (Department of Computer Science)  
18 Feb 2005  Harrison 171 Friday 4pm  Computer Science (Internal) 
Traditional optimisation research has concentrated on the singleobjective case, where one measure of the quality of the system is optimised exclusively. Most realworld problems, however, are constructed from multiple, often competing, objectives which prevent the use of singleobjective optimisers. Here a generic mapping to a single objective function is proposed for multiobjective problems, allowing singleobjective optimisers to be used for the optimisation of multiobjective problems. A simulated annealer using this method is proposed which uses this technique and is shown to perform well on both test and commercial problems.  
 
A conservation of fragility law and its consequences for biochemical network dynamics (POSTPONED until 19 May)  
Jorge Gonçalves (Cambridge University)  
17 Feb 2005  Laver LT321 Thursday 2pm  Applied Mathematics 
Robustness is a defining feature of successful complex systems. In this talk I will describe a fundamental limit on the robustness of complex systems achievable through feedback control. Based on a generic formulation of the control problem, we define /fragility/ in terms of the sensitivity of an output to a disturbance and derive an integral constraint (lowerbound) on the net fragility of a system. Put simply, reducing the sensitivity to disturbances at one range of frequencies by feedback control will necessarily amplify disturbances at other frequencies. For the special case of linear feedback systems, this result reduces to Bode's integral formula. We illustrate the implications of this robustness tradeoff for biological systems, and identify feedforward control and buffering as strategies for ameliorating the tradeoff. Finally, the theory provides an alternate interpretation of Shannon's channel capacity theorem for nonlinear control systems.  
 
Topological invariants of singular spaces  
Burt Totaro (Cambridge)  
17 Feb 2005  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Synchronization in Kuramotolike model of globally coupled oscillators  
Alexander Burilko (Kiev)  
14 Feb 2005  Harrison 106 Monday 10am  Applied Mathematics (Internal) 
 
Identifying Familiarity and Dialogue Type in Transcribed Texts  
Andrew Lee (Department of Computer Science)  
11 Feb 2005  Harrison 171 Friday 4pm  Computer Science (Internal) 
In a spoken dialogue, there is a lot of information that is not explicitly
stated but can be identified through nonlinguistic features, such as tone
of voice or a change in speaker. However, this information is not always
available when the conversation is transcribed into a written text.
In this talk, I'll be describing methods for measuring two aspects of dialogues that can be lost when transcribed: the familiarity between participants and the type of dialogue. In the case of familiarity, Dialogue Moves are counted for conversational transcripts from the Map Task corpus. The differences in Dialogue Move pair distributions are compared between transcripts where participants are either familiar or unfamiliar with each other to explore whether a measure of familiarity can be based on this approach. To identify the type of dialogue, the frequency distribution of Verbal Response Modes in a transcribed text are counted for number of different dialogues, including interviews, presentations and speeches. Profiles generated from the frequency distributions are then be used as a basis for comparison to identify the closest matching dialogue type.  
 
Interactions between vortices, boundaries and bottom topography  
Ted Johnson (University College London)  
7 Feb 2005  Harrison 170 Monday 2pm  Applied Mathematics 
 
Eddy scaling for poleward heat transport in Earth's atmosphere  
John Thuburn (UIniversity of Exeter)  
7 Feb 2005  Harrison 106 Monday 10am  Applied Mathematics (Internal) 
 
ROC Optimisation of Safety Related Systems  
Jonathan Fieldsend (Department of Computer Science)  
4 Feb 2005  Harrison 171 Friday 4pm  Computer Science (Internal) 
In this talk the tuning of critical systems is cast as a multiobjective optimisation problem. It is shown how a region of the optimal receiver operating characteristic (ROC) curve may be obtained, permitting the system operators to select the operating point. This methodology is applied to the STCA system, showing that the current handtuned operating point can be improved upon, as well as providing the salient ROC curve describing the truepositive versus falsepositive tradeoff. In addition, through bootstrapping the data we can also look at the effect of data uncertainty on individuals parameterisations, and the ROC curve as a whole.  
 
Ultrasound Image Segmentation  
Professor Alison Noble (University of Oxford)  
3 Feb 2005  Harrison 254 Tuesday 3pm  Computer Science 
Ultrasound image segmentation is considered a challenging
area of medical image analysis as clinical images vary in
quality and image formation is nonlinear. Most classicial
approaches to segmentation do not work well on this data.
In this talk, I will provide an overview of research we have done in this area, using what I call weak physics based approaches, specifically looking at the tasks of displacement estimation, and segmentation of tissue regions and perfusion uptake.  
 
Picard groups of some module categories  
Peter Vamos (University of Exeter)  
3 Feb 2005  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Hilbert's 16th problem  some analytic and algebraic aspects  
Colin Christopher (University of Plymouth)  
31 Jan 2005  Harrison 170 Monday 2pm  Applied Mathematics 
The second part of Hilbert's 16th problem deals with the number of limit cycles of polynomial vector fields in the plane. It remains one of the few of the original 23 problems that have not been substantially solved over the past century. However, over the past twenty years or so, insights from the theory of foliations and algebraic geometry as well as improved analytic techniques have brought many new advances to our understanding of this old problem. My aim in the talk is to give a brief survey of some of these recent advances as well as the many open questions which surround the study of polynomial vector fields in the plane.  
 
Quasigeostrophic approximation revisited  
Keke Zhang (University of Exeter)  
31 Jan 2005  Harrison 106 Monday 10am  Applied Mathematics (Internal) 
 
Random preorders  
Dudley Stark (Queen Mary)  
27 Jan 2005  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Highdimensional chaos in the Kuramoto model  
Yuri Maistrenko (Kiev)  
24 Jan 2005  Harrison 106 Monday 10am  Applied Mathematics (Internal) 
 
Adopting Open Source tools in a production environment: are we locked in?  
Brian Lings (Department of Computer Science)  
21 Jan 2005  Harrison 171 Friday 4pm  Computer Science (Internal) 
Many companies are using modelbased techniques to offer a competitive advantage in an increasingly globalised systems development industry. Central to modelbased development is the concept of models as the basis from which systems are generated, tested and maintained. The availability of highquality tools, and the ability to adopt and adapt them to the company practice, are therefore important qualities. Model interchange between tools becomes a major issue. Without it, there is significantly reduced flexibility, and a danger of tool lockin. In this talk I report on a case study in which a systems development company, SAAB Combitech, has explored the possibility of complementing their current proprietary tools by exporting models in XMI to open source products for supporting their modelbased development activities. We found that problems still exist with interchange, and that the technology needs to mature before industrialstrength model interchange becomes a reality.  
 
TBA  
Dr Sunil Vadera  
20 Jan 2005  Harrison 209 Tuesday 3pm  Computer Science 
Much of our daily reasoning appears to be based on stereotypes, exemplars and anecdotes. Yet, basic statistics informs us that decisions based only limited data are, at best, likely to be inaccurate, if not badly wrong. However, exemplars and stereotypes are not arbitrary data points, they are based on experience and represent prototypical situations. The ability to predict the behaviour of a consumer, observe that two people are related, diagnose an illness, and even how an MP might vote on a particular issue, all depend on a person's past experience  that is the exemplars and stereotypes a person learns. If this hypothesis, namely that we can form and reason well with exemplars is true, we should be able to identify exemplars from data. To achieve this, we need to answer the following questions: (a) What is an exemplar and how can it be represented? (b) How do we learn good exemplars incrementally? (c) How can exemplars be used? This seminar presents an approach to these questions that involves the use of the notion of family resemblance to learn exemplars and Bayesian networks to represent and utilise exemplars. Empirical results of applying the model will be presented and relationships with other models of machine learning also discussed.  
 
Corner eddies: new variations on an old theme  
Keith Moffatt (Cambridge University)  
17 Jan 2005  Harrison 170 Monday 2pm  Applied Mathematics 
 
MODELLING THROUGH: The growing role of decision analytic models in Health Technology Assessment  
Martin Pitt (Department of Computer Science)  
14 Jan 2005  Harrison 171 Friday 4pm  Computer Science (Internal) 
In recent years, analytic modelling has been widely used to support decision
making within the National Health Service (NHS) for a range of applications
and with varying levels of success.
A recent development has been the adoption of mathematical and computer based models as a central element if the process of Health Technology Assessment (HTA). HTA is concerned with the evaluation of alternative healthcare interventions (eg alternative drug therapies) in order to directly inform decision making. It is now at the forefront of health research in the UK representing the largest single strand of NHS funded research activity. HTA outputs form a key element in the process by which the National Institute for Clinical Excellent determine general guidelines for UK prescription and clinical practice. This presentation will take an informal look at the rapidly developing field of decision analytic modelling in field HTA. It will outline the range of alternative mathematical and computer based approaches adopted with reference to case study examples, and illustrate how model outputs feed into the decision making process. Key challenges within this field, such as how data uncertainty is handled, will be examined in relation to current areas of active development.  
 
Dynamics of delayed relay systems  
Jan Sieber (University of Bristol)  
10 Jan 2005  Harrison 170 Monday 2pm  Applied Mathematics 
 
***Jonas Gamalielsson  Developing a Method for Assessing the Interestingness of Rules Induced from Microarray Gene Expression Data ***Zelmina Lubovac  Revealing modular organization of the protein interactome by combining its topological and functional properties ***Simon Lundell  Modelling the Heamatopoietic Stem Cell System.  
Jonas Gamalielsson, Simon Lundell and Zelmina Lubovac  
17 Dec 2004  Harrison 209 Wednesday 3pm  Computer Science 
***Jonas Gamalielsson  Abstract :The aim and contribution of this work is to develop a method for assessing the interestingness of rules induced from microarray gene expression data using a combination of objective and domain specific measures, which will assist biologists in finding the most interesting hypotheses to test after mining for rules in microarray gene expression data and also generate more accurate models than if objective measures alone were used. More specifically, a method is being developed for assessing the biological plausibility of hypothetic regulatory relations generated by data mining algorithms applied to gene expression data. The idea is to use an information fusion approach where knowledge is used about the Gene Ontology functional classification of gene products and the topology of known regulatory pathways with the purpose of generating templates representing general knowledge of regulation in pathways. Templates show what kind of gene products with respect to molecular function that have been found to participate in different types of regulatory relations in pathways. A training set of regulatory relations is used to derive the templates. A test set of hypothetic regulatory relations is used to assess how well the templates can distinguish between hypothetic relations showing a high and low level of biological plausibility with respect to the set of training relations. ***Zelmina Lubovac Abstract :Understanding the structure of the protein interaction network is useful as a first step towards revealing the underlying principles of the largescale organisation of the cell. In this project, we analyse a topological characterisation of the yeast (/Saccharomyces cerevisiea/) proteinprotein interaction network, and relate it to functional annotations from Gene Ontology (GO). We aim to develop a biologically informed measure to reveal modular formations in an interactome. A semantic similarity measure has been used to assess the role of hubs in a network in terms of functional annotation from GO. The existing graph theoretic notion of the module has been used in previous work to perform a modular decomposition of the protein network, i.e. to break down subgraphs into a hierarchy of nested modules or units that groups proteins with common functional roles. Our attempt is to complement the existing graph theoretic approach with semantic similarity based on proteins? ontological terms to achieve more biologically plausible descriptions of modular decomposition. ***Simon Lundell Abstract :During life of higher animals the heamatopoietic system produces blood, with a composition of various cell types, e.g. lymphocytes, erythrocytes and platelets. This system has to adopt to the animals growth and for changes such as stress conditions, e.g. infection and blood loss. If the animal is infected then a new composition of blood cells is needed as well as a compensation for the cells lost in the battle against the intruder. The heamatopoietic system is a highly adaptable and has stem cells that are dormant in long periods of time. The dormant cells can,when needed, be proliferated, and may then give rise to millions of new cells. The regulation of the number of heamatopoietic cells is crucial to animals; the heamatopoietic system must avoid depletion of stem cells as well as excess production of cells, both instances are life threatening conditions. A mouse produces 60% of its body weight in blood cells in its lifetime and a human produces 10 times its body weight. Although the large production of blood cells only a few stem cells has been stated as necessary to recreate hematopoietic system. Using an object based model of this system we were able to reproduce experimental data, and were able to find out which types of feedback regulations are active during stem cell transplantation. The systems intricate organisation, dynamic structure and the need to compare the simulations to a large number of experimental setups, opts for a new way of organising these models.  
 
Wiggly Outlines: The Ins and Outs of Nonconvex Hulls  
Antony Galton (Department of Computer Science)  
17 Dec 2004  Harrison 171 Friday 4pm  Computer Science (Internal) 
Given a set of objects located in space, how can we represent the region occupied by those objects at different granularities? At a very fine granularity, the region simply consists of all the points occupied by the objects themselves, whereas at a very coarse granularity it might be given by the convex hull of those points. In many cases, neither of these representations is very useful: what we want is some kind of nonconvex hull to convey the overall 'shape' of the region. But whereas the convex hull of a set of points is uniquely defined, there are any number of candidates for their nonconvex hull. In this talk I shall introduce and explore some of the properties of a family of nonconvex hulls generated by a generalisation of a simple convexhull algorithm.  
 
TBA  
Achim Ilchmann (Ilmenau, Germany)  
10 Dec 2004  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
A personal view of computer assisted formal reasoning  
Matthew Fairtlough (University of Sheffield)  
10 Dec 2004  Harrison 171 Friday 4pm  Computer Science (Internal) 
I will survey my work of the last 13 years in the field of logic and formal reasoning; in particular I will discuss the methods, logics, implementations, tools and applications involved. The most striking development has been a new modal logic called Lax Logic, so my talk will focus on this. I will give a flavour of the logic itself and of its application to formal reasoning across (multiple) abstraction boundaries, where inevitably constraints arise whose values may not be precisely known in advance. I will end by presenting some recent work using Mathematica to analyse and animate a dynamic 3dimensional lattice.  
 
Ultrasound attenuation as a quantitative measure of fracture healing  
Dr Sabina Gheduzzi (University of Bristol)  
9 Dec 2004  Harrison 203 Thursday 2pm  Engineering 
The monitoring of fracture healing still relies upon the judgement of callus formation and on the manual assessment of the stiffness of the fracture. A diagnostic tool capable of quantitatively measuring healing progression of a fracture would allow the finetuning of the treatment regime. Ultrasound attenuation measurements were adopted as a possible method of assessing the healing process in human long bones. The method involves exciting ultrasonic waves at 200 kHz in the bone and measuring the reradiation along the bone and across the fracture zone. Seven cadaveric femora were tested invitro in intact form and after creating a transverse fracture by sawing through the cortex. The effects of five different fracture types were investigated. A partial fracture, corresponding to a 50% cut through the cortex, a closed fracture and fractures of widths varying between 1, 2 and 4 mm were investigated. The introduction of a fracture was found to produce a dramatic effect on the amplitude of the signal. Ultrasound attenuation was found to be sensitive to the presence of a fracture, even when the fracture was well reduced. It would therefore appear feasible to adopt attenuation across a fracture as a quantitative measurement of fracture healing.  
 
On the AndreOort conjecture  
Andrei Yafaev (University College, London)  
9 Dec 2004  Harrison 106 Thursday 3pm  Pure Mathematics 
The AndreOort conjecture asserts that the Zariski closure of a set of special points in a Shimura variety is a subvariety of Hodge type. In this talk I will present recent results on this conjecture and an application to the transcendence theory of hypergeometric functions.  
 
A numerical scheme for stochastics PDEs  
Gabriel Lord (HeriotWatt University)  
6 Dec 2004  Harrison 170 Monday 2pm  Applied Mathematics 
 
New Effects in MeanField Magnetic Dynamos  
Igor Rogachevskii (BenGurion University, BeerSheva, Israel)  
3 Dec 2004  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Seeing where the other guy is coming from: A survival guide for young researchers working in multidisciplinary subjects.  
James Hood (Department of Computer Science)  
3 Dec 2004  Harrison 171 Friday 4pm  Computer Science (Internal) 
Part of the confidence I have gained recently in my own work is the result of trying to see where different disciplinary groups in my general field of research are coming from  what they are trying to gain in doing what they are doing. This action, which has led to a better understanding of my own research goals, was not possible until I situated my own research against that of a greater research community. The upshot of this exercise was my very own 'research map', on which, as the product of generalisation of people and groups, I felt I had a better idea of not only where the different groups where coming from, but also where I was going to. In this talk I want to present to you my research map and my experiences of and the lessons I have learned from creating it. Bridge building in multidisciplinary research is now so important that all of us could benefit from doing a little map making every now and then. I hope therefore that this talk will be of some interest.  
 
Iwasawa theory for elliptic curves at supersingular primes  
Shinuchi Kobayashi (University of Paris)  
2 Dec 2004  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Postgraduate Seminar Spatial Survival Analysis and the FMD epidemic in Devon  
Trevelyan McKinley (University of Exeter)  
2 Dec 2004  Exeter University Laver, 321 Thurs 2pm  Statistics & Operational Research 
The magnitude of the potential economic impacts of epidemic animal disease events have been highlighted in recent years through outbreaks such as the footandmouth disease epidemic in the United Kingdom during 2001. This talk reports some initial work from a project in conjunction with the Veterinary Laboratory Agency, Weybridge, which is looking at the feasibility of using survival modelling to develop dynamic spacetime predictions of survivor and hazard functions for individual farm premises as an animal disease epidemic progresses. Survival analysis used in a spatial context is a potentially useful approach to quantifying the risk of infection of susceptible premises within future time periods given the characteristics of these premises and their geographical location relative to potential sources of infection. Results from such analyses could provide powerful insights into the patterns of infection, such as regional differences in the dynamics of the epidemic, and can assist in optimising various aspects of the operational response activities, such as targeting of atrisk farms. We consider various possible model formulations and apply a range of these to data from Devon for the 2001 UK FMD epidemic.  
 
Rates of mixing in hyperbolic flows  
Mike Field (University of Houston, USA)  
29 Nov 2004  Harrison 170 Monday 2pm  Applied Mathematics 
 
TBA  
Paolo Rapisarda (University of Southampton)  
27 Nov 2004  Harrison 254 Monday 2pm  Applied Mathematics 
 
Stellar differential rotation  
Guenther Rudiger (Potsdam, Germany)  
26 Nov 2004  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
This seminar has been cancelled owing to illness  
 
Isotropy of quadratic forms in finite and infinite dimension  
Detlev Hoffmann (University of Nottingham)  
25 Nov 2004  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Unpredictability in population dynamics  
Josef Hofbauer (University College London)  
22 Nov 2004  Harrison 170 Monday 2pm  Applied Mathematics 
 
Quasigeostrophic approximation revisited  
Keke Zhang (Mathematical Sciences)  
19 Nov 2004  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
This seminar has been postponed until early in the new year  date to be advised  
 
Explanatory Shifts and structures for knowledge  
Donald Bligh (Department of Computer Science)  
19 Nov 2004  Harrison 171 Friday 4pm  Computer Science (Internal) 
Explanations involve fitting what is to be explained into a context that has already formed in the minds or brains of he who explains and he who tries to understand. But how did they come to understand that preformed context? By fitting it into an earlier preformed context and so on ad infinitum?
Well no, not quite. Eventually you reach fundamental elements of preformed contexts of which there are at least ten: sameness, difference, change, direction, force, awareness, like/dislike, obligation and intention. Just as items of knowledge are built upon previous knowledge, so their preformed contexts build upon each other. The elements build upon each other in ever more complex ways, a bit like complex molecular structure built of simple elements. When asked to justify an explanation the reverse process of occurs – analysis or deconstruction of the explanation. If so the justification is in a different context from the explanation being justified. That is what I call an explanatory shift.  
 
Semisymmetric cubic graphs  
Chris Parker (University of Birmingham)  
18 Nov 2004  Harrison 106 Thursday 3pm  Pure Mathematics 
 
RSS Local Group Meeting: Competing Risks: a brief introduction  
Martin Crowder (Imperial College)  
18 Nov 2004  Exeter University Laver, 321 Thurs 2pm  Statistics & Operational Research 
The origins of Competing Risks date back to Bernoulli's attempt in 1760 to disentangle the risk of dying from smallpox from other risks. Much subsequent work has been demographic and actuarial in nature and although obviously of potential relevance in Reliability and Survival Analysis, applications to those fields are quite recent. The talk will cover some of the basic ideas and application of the subject.  
 
Different limiting mechanisms for nonlinear dynamos  
Dave Galloway (University of Sydney, Australia)  
15 Nov 2004  Harrison 170 Monday 2pm  Applied Mathematics 
 
Piecewise Isometric Disk Packings and the Arbelos  
Marcello Trovati (Mathematical Sciences)  
12 Nov 2004  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Theory of Molecular Computing. Splicing and Membrane systems  
Pier Frisco (Department of Computer Science)  
12 Nov 2004  Harrison 171 Friday 4pm  Computer Science (Internal) 
Molecular Computing is a new and fast growing field of research at the interface of computer science and molecular biology driven by the idea that molecular processes can be used for implementing computations or can be regarded as computations. This research area has emerged in recent years not only as a novel technology for information processing, but also as a catalyst for knowledge transfer between the fields of information processing, nanotechnology and biology. Molecular Computing (together with research areas such as Quantum Computing, Evolutionary Algorithms and Neural Networks) belongs to Natural Computing which is concerned with computing taking place in nature and computing inspired by nature. In this talk I will give an overview of my research in the theoretical aspects of Molecular Computing. In particular I will talk about two theoretical models of computation: splicing systems and membrane systems.  
 
Additive decompositions of the primes  
Christian Elsholtz (Royal Holloway, University of London)  
12 Nov 2004  Harrison LT6 Friday 3pm  Pure Mathematics 
 
Statistics Seminar Limited and full information estimation and goodnessoffit testing in 2^n contingency tables: A unified framework  
Albert MaydeuOlivares (Faculty of Psychology, University of Barcelona)  
12 Nov 2004  Exeter University Laver B74 Friday 4pm  Statistics & Operational Research 
Highdimensional contingency tables tend to be sparse and standard goodnessoffit statistics such as chisquare cannot be used without pooling categories. As an improvement on arbitrary pooling, for goodnessoffit of large 2^n contingency tables, we propose classes of quadratic form statistics based on the residuals of margins or multivariate moments up to order r. These classes of test statistics are asymptotically chisquare. Further, the marginal residuals are useful for diagnosing lack of fit of parametric models. We show that when r is small (r = 2,3) the proposed statistics have better small sample properties and are asymptotically more powerful than chisquare for some useful multivariate binary models. Related to these test statistics is a class of limited information estimators based on lowdimensional margins. We show that these estimators have high efficiency for one commonly used latent trait model for binary data (the two parameter logistic IRT model)  
 
Fractals and Image Processing  
Professor Revathy  
11 Nov 2004  Harrison 209 Tuesday 3pm  Computer Science 
 
Corings and Galois theory  
Tomasz Brzezinski (Swansea, University of Wales)  
11 Nov 2004  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Cycling cycles: Dynamics near a heteroclinic network  
Claire Postlethwaite (Cambridge University)  
8 Nov 2004  Harrison 170 Monday 2pm  Applied Mathematics 
 
The role of inertia in the evolution of spherical dynamos  
Binod Sreenivasan (Mathematical Sciences)  
5 Nov 2004  Harrison LT3 Wednesday 2pm  Applied Mathematics (Internal) 
 
A Painless Introduction to Mereogeometry  
Dr Ian PrattHartmann (University of Manchester)  
4 Nov 2004  Harrison 209 Tuesday 3pm  Computer Science 
One of the many achievements of coordinate geometry has been to provide a conceptually elegant and unifying account of spatial entities. According to this account, the primitive constituents of space are points, and all other spatial entitieslines curves, surfaces and bodiesare nothing other than the sets of those points which lie on them. The success of this reduction is so great that the identification of all spatial objects with sets of points has come to seem almost axiomatic. For most of the previous century, however, a small but tenacious band of authors has suggested that more parsimonious and conceptually satisfying representations of space are obtained if we adopt an ontology in which regions, not points, are the primitive spatial entities. These, and other, considerations have prompted the development of formal languages whose variables range over certain subsets (not points) of specified classes of geometrical structures. We call the study of such languages `mereogeometry'. In the past decade, the Computer Science community in particular has produced a steady flow of new technical results in mereogeometry, especially concerning the computational complexity of regionbased topological formalisms with limited expressive power. The purpose of this talk is to survey this work in general and (largely) nontechnical terms. In particular, we aim to locate the various recent mathematical results in mereogeometry within a general mathematical framework. The result will be an inventory of stock and a list of open problems.  
 
Companion forms  
Toby Gee (Imperial College, London)  
4 Nov 2004  Harrison 106 Thursday 3pm  Pure Mathematics 
 
How long can left and right handed life forms coexist?  
Axel Brandenburg (NORDITA, Copenhagen, Denmark)  
1 Nov 2004  Harrison 170 Monday 2pm  Applied Mathematics 
 
Dynamics, Damping and Defects in Thin Ferromagnetic Films  
Robert D. McMichael (US National Institute of Standards and Technology)  
29 Oct 2004  Newman E Friday 11am  Engineering 
Modern disk drives can read and write bits every two nanoseconds, a time scale very similar to the magnetic damping time of the ferromagnetic metals used in the heads. The damping characteristics are also important for thermallydriven magnetic noise in sensors. Furthermore, it seems likely that damping will limit data rates in magnetic random access memory, since the magnetization in a memory cell must be allowed to settle between switching events. For all of these applications, measurements of damping are important, and these measurements are most commonly made by ferromagnetic resonance linewidth. The two problems that complicate measurements of damping by ferromagnetic resonance are: 1) defects contribute to the linewidth, so that the linewidth is the combined effect of defects and damping, and 2) the form of the damping itself is the subject of some debate.  
 
$p$groups and semistable reduction of curves  
Mohamed Saidi (University of Exeter)  
28 Oct 2004  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Introduction to de RhamWitt cohomology  
Andreas Langer (University of Exeter)  
26 Oct 2004  Harrison B93 Tuesday 3pm  Pure Mathematics 
 
Zonal flows and magnetic fields in laboratory plasmas  
Pat Diamond (University of California, San Diego, USA)  
25 Oct 2004  Harrison 170 Monday 2pm  Applied Mathematics 
 
Beilinson's conjecure for $K_2$ of certain (hyper)elliptic curves  
Rob de Jeu (University of Durham)  
21 Oct 2004  Harrison 106 Thursday 3pm  Pure Mathematics 
 
A mechanism of solar variability influence on climate  
Alexander Ruzmaikin (JPL, Pasadina, USA)  
18 Oct 2004  Harrison 170 Monday 2pm  Applied Mathematics 
 
Investigation and monitoring of tunnelling works at Lewes, incorporating the ABI Code of Practice for Tunnelling.  
Dr Robert Hodgson (Black & Veatch)  
14 Oct 2004  Harrison 203 Thursday 2pm  Engineering 
 
Matrix functions: Theory and algorithms  
Nick Higham (University of Manchester)  
11 Oct 2004  Harrison 170 Monday 2pm  Applied Mathematics 
 
The slowfast myth in geophysical fluid dynamics  
David Dritschel (University of St Andrews)  
4 Oct 2004  Harrison 170 Monday 2pm  Applied Mathematics 
 
A model of crosscontamination by wind in genetically modified oilseed rape  
Martin Hoyle (Biological Sciences)  
24 Sep 2004  Harrison L40 Wednesday 11am  Applied Mathematics (Internal) 
 
TBA  
Professor Peter Cowling (Bradford University)  
10 Jun 2004  Harrison 209 Tuesday 3pm  Computer Science 
 
Machine Consciousness  
Dr Owen Holland (University of Exeter)  
3 Jun 2004  Harrison 209 Tuesday 3pm  Computer Science 
 
The work at the Hadley Centre for Climate Prediction and Research, Met Office  
Dr Vicky Pope (The Met Office)  
26 May 2004  Harrison 209 Tuesday 3pm  Computer Science 
 
Quantification of the effect of flow on the initial processes of bacterial attachment.  
Mr John Boyle  
20 May 2004  Harrison 203 Thursday 2pm  Engineering 
 
Agents and affect: why embodied agents need affective systems.  
Professor Ruth Aylett (Salford University)  
13 May 2004  Harrison 209 Tuesday 3pm  Computer Science 
 
Modulling the Micromechanics of Auxetics (Stealing ideas from granular mechanics)  
Dr Neil Gaspar  
13 May 2004  Harrison 203 Thursday 2pm  Engineering 
 
Logicbased visual perception for a humanoid robot  
Dr Murray Shanaham (Imperial College)  
6 May 2004  Harrison 209 Tuesday 3pm  Computer Science 
 
The aerodynamics of airborne pollen: how do pines pollinate? (Or, is nature really that stupid?)  
Dr James Cresswell and Dr Gavin Tabor  
6 May 2004  Harrison 203 Thursday 2pm  Engineering 
 
Future Floods  the Foresight flood and coastal defence project.  
Professor Richard Ashley  
5 May 2004  Harrison 203 Thursday 9.15am  Engineering 
 
Imprecise methods for analysing uncertainty in climate projections and impacts.  
Dr Jim W Hall  
29 Apr 2004  Harrison 203 Thursday 2pm  Engineering 
 
Asymptotic structure of biological excitability equations  
Vadim Biktashev (University of Liverpool)  
8 Dec 2003  Harrison 170 Monday 2pm  Applied Mathematics 
 
Nonlinear Schroedinger equations as models of superfluidity  
Natalia Berloff (Cambridge University)  
1 Dec 2003  Harrison 170 Monday 2pm  Applied Mathematics 
 
To be announced  
Adam Epstein (Warwick)  
27 Nov 2003  Harrison 106 Thursday 3pm  Pure Mathematics 
 
To be announced  
Adam Epstein (Warwick)  
27 Nov 2003  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Magnetic fields in numerical simulations of the interstellar medium  
Graeme Sarson (University of Newcastle)  
24 Nov 2003  Harrison 170 Monday 2pm  Applied Mathematics 
 
Stability of Hamiltonian relative equilibria and applications to underwater vehicles  
Claudia Wulff (University of Surrey)  
17 Nov 2003  Harrison 170 Monday 2pm  Applied Mathematics 
 
To be announced  
Daniel Delbourgo (Nottingham)  
13 Nov 2003  Harrison 106 Thursday 3pm  Pure Mathematics 
 
To be announced  
Daniel Delbourgo (Nottingham)  
13 Nov 2003  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Qualitative behaviour of thin liquid metal layers at low magnetic Reynolds number  
Paul Dellar (Oxford University)  
10 Nov 2003  Harrison 170 Monday 2pm  Applied Mathematics 
 
To be announced  
Alan Camina (UEA)  
6 Nov 2003  Harrison 106 Thursday 3pm  Pure Mathematics 
 
To be announced  
Alan Camina (UEA)  
6 Nov 2003  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Robust control of 2D and 3D channel flow with CFD validation  
Eric Rogers (University of Southampton)  
3 Nov 2003  Harrison 170 Monday 2pm  Applied Mathematics 
 
To be announced  
Victor Flynn (Liverpool)  
30 Oct 2003  Harrison 106 Thursday 3pm  Pure Mathematics 
 
To be announced  
Victor Flynn (Liverpool)  
30 Oct 2003  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Renormalization in interval translation maps  
Henk Bruin (University of Surrey)  
27 Oct 2003  Harrison 170 Monday 2pm  Applied Mathematics 
 
To be announced  
Sophie Huczysnka (Edinburgh)  
23 Oct 2003  Harrison 106 Thursday 3pm  Pure Mathematics 
 
To be announced  
Sophie Huczysnka (Edinburgh)  
23 Oct 2003  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Formation of vortices and jets in rotating convection on a betaplane: Jupiter's belts and zones in the laboratory  
Peter Read (Oxford University)  
20 Oct 2003  Harrison 170 Monday 2pm  Applied Mathematics 
 
To be announced  
Tom Korner (Cambridge)  
16 Oct 2003  Harrison 106 Thursday 3pm  Pure Mathematics 
 
To be announced  
Tom Korner (Cambridge)  
16 Oct 2003  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Two MHD problems: Helical dynamos and the pulsar magnetosphere  
Jonathan Mestel (Imperial College)  
13 Oct 2003  Harrison 170 Monday 2pm  Applied Mathematics 
 
Dynamics of impacting systems: Theory and experiments  
Marian Wiercigroch (Aberdeen University)  
6 Oct 2003  Harrison 170 Monday 2pm  Applied Mathematics 
 
Strange attractors and their basins  
Yongluo Cao (Suzhou University)  
18 Sep 2003  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Quasipatterns in surface waves  
Alastair Rucklidge (Leeds University)  
10 Sep 2003  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Shape optimization for induction hardening  
Jan Sokolowski ('Henrie Poincare University, Nancy')  
11 Jul 2003  Harrison 170 Monday 2pm  Applied Mathematics 
 
Dynamos and convection: mean flow generation  
Jon Rotvig (University of Exeter)  
13 Jun 2003  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
RSS Local Group Meeting: Measurement error, power and sample size in geneenvironment interaction studies  
Jian'an Luan (University of Cambridge)  
11 Jun 2003  Laver None None  Statistics & Operational Research 
See here for abstract  
 
Partial stability and stabilization. Part 2  
Reza Rokni Lamooki (University of Exeter)  
6 Jun 2003  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Partial stability and stabilization. Part 1: an introduction  
Reza Rokni Lamooki (University of Exeter)  
30 May 2003  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
RSS Local Group Meeting: Machine Learning Techniques for Bioinformatics  
Colin Campbell (University of Bristol)  
29 May 2003  Laver None None  Statistics & Operational Research 
See here for abstract  
 
Operational Research Seminar: A cash flow criterion for controlling a base stock inventory system  
Roger Hill (University of Exeter)  
22 May 2003  Laver None None  Statistics & Operational Research 
It is common practice to control certain inventory systems using a 'base stock' policy and the standard approach is then to associate timeweighted costs with holding stock and with having unsatisfied demand and to determine the base stock which minimises the long run average total cost per unit time. This approach ignores the impact of the control policy on the timing of the cash flows associated with payments made to suppliers and revenues received from customers. The approach made here is to concentrate on cash flows and determine the control policy which optimises an appropriate cash flow measure. The impact of the control system is measured in two ways. Firstly, if a customer order is met immediately from stock then we determine for how long that unit has been held in stock and compute the corresponding compound loss of interest resulting from having paid the supplier for it early. Secondly, if a customer order is not met from stock then we determine the delay in meeting that demand and the consequent loss of interest which could have been earned on the customer payment if it had not been delayed. The objective is to minimise the total expected cash flow impact per unit time. A solution procedure is given and a comparison is made between this approach and other ways of controlling this system.  
 
The AKS algorithm  
Robin Chapman (University of Exeter)  
21 May 2003  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Integrability of Hamiltonian systems: from Poincare to Ziglin.  
Alexei Tsygvinstev (University of Exeter)  
19 May 2003  Harrison 170 Monday 2pm  Applied Mathematics 
 
To be announced  
Rahman Bahmani Sangsari (University of Exeter)  
14 May 2003  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Pinching without branch points: new mechanism for absolute instability  
Jonathan Healey (Keele University)  
12 May 2003  Harrison 170 Monday 2pm  Applied Mathematics 
 
Statistics Seminar: Bootstrapping SIR for Dimension Assessment in a General Regression Problem  
Santiago Velilla (Universidad Carlos III de Madrid)  
8 May 2003  Laver None None  Statistics & Operational Research 
A bootstrap method is constructed for assessing the dimension of a general regression problem. A resampled version of the matrix used in the SIR method of Li (1991) is obtained, and the bootstrap distributions of the statistics of interest characterized. The proposed methodology incorporates both formal and graphical inference procedures and can be considered as an alternative to the permutation test of Cook and Yin (2001).  
 
To be announced  
Julie Fowler (University of Exeter)  
7 May 2003  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Cuntz and Leavitt algebras  
Peter Vámos (University of Exeter)  
30 Apr 2003  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Chaotic mixing and eigenfunctions  
JeanLuc Thiffeault (Imperial College)  
28 Apr 2003  Harrison 170 Monday 2pm  Applied Mathematics 
 
Infinite Designs  
Bridget Webb (Open University)  
20 Mar 2003  Harrison 106 Thursday 3pm  Pure Mathematics 
Infinite designs are quite rare in the literaturemost books on design theory have no mention of them at all. In this talk I will present a brief history of infinite designs, give a precise definition, and compare some properties of finite and infinite designs.  
 
Cuntz and Leavitt algebras  (POSTPONED)  
Peter Vámos (University of Exeter)  
19 Mar 2003  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Characterization of a family of tworoll mill flows  
Jonathan Kobine (University of Dundee)  
17 Mar 2003  Harrison 170 Monday 2pm  Applied Mathematics 
 
Convergence groups and Hausdorff dimension  
James Anderson (Southampton)  
13 Mar 2003  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Statistics Seminar: Nonparametric classification exploiting separation of populations  
Adolfo Hernandez (University of Exeter)  
13 Mar 2003  Laver None None  Statistics & Operational Research 
Kernel discriminant analyisis is greatly affected by the wellknown phenomenon often referred to as the 'curse of dimensionality'. This causes bad behaviour of the rules because of the amount of data required as the dimension of the problem increases. In this seminar two dimension reduction methods are proposed, based on the concept of separation of populations. The basic idea is firstly to obtain a dimension reduction subspace through the maximization of certain functionals which can be seen as indexes of separation, and, secondly, to evaluate a reduced kernel discriminant rule in that subspace. The good behaviour of these methods is justified both theoretically and also through application to data sets where comparisons with other methods proposed in the literature can be established.  
 
Asymptotics of class numbers  
Anton Deitmar (University of Exeter)  
12 Mar 2003  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
The structure of periodic causal operators on L^{2}  
George Weiss (Imperial College London)  
10 Mar 2003  Harrison 170 Monday 2pm  Applied Mathematics 
 
The McKay correspondence in dimension 3  
Alistair King (Bath)  
6 Mar 2003  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Hermitian structures on lattices  
Robin Chapman (University of Exeter)  
5 Mar 2003  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Energy, helicity and crossing number relations for complex flows  
Renzo Ricca (University College London)  
3 Mar 2003  Harrison 170 Monday 2pm  Applied Mathematics 
 
The Arithmetic of Quadratic Recurrence Sequences  
Graham Everest (East Anglia)  
27 Feb 2003  Harrison 106 Thursday 3pm  Pure Mathematics 
 
RSS Local Group Meeting: Markov Chain Monte Carlo exact inference for binomial and multinomial logistic regression models  
John MacDonald (University of Southampton)  
27 Feb 2003  Laver None None  Statistics & Operational Research 
See here for abstract  
 
Nonlinear waves in diverging flows  
Rich Kerswell (University of Bristol)  
24 Feb 2003  Harrison 170 Monday 2pm  Applied Mathematics 
 
Generalized blocks for symmetric groups  
Geoffrey Robinson (Birmingham)  
20 Feb 2003  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Statistics Seminar: Spatial modelling of childhood malaria in the Gambia  
Rana Moyeed (University of Plymouth)  
20 Feb 2003  Laver None None  Statistics & Operational Research 
A spatial generalized linear mixed model is developed to describe the variation in malarial prevalence amongst a sample of village resident children in the Gambia. The response from each child is a binary indicator of the presence of malarial parasites in a bloodsample. The model includes terms for the effects of childlevel covariates, villagelevel covariates and separate components for residual spatial and nonspatial extrabinomial variation. The results show that the extrabinomial variation is spatially structured, suggesting an environmental effect rather than variation in familial susceptibility. The method of inference was Bayesian using vague priors and a Markov chain Monte Carlo implementation.  
 
Parametrisation of attractors and Takens embedding thereom  
James Robinson (University of Warwick)  
17 Feb 2003  Harrison 170 Monday 2pm  Applied Mathematics 
 
Paths in the cube  
Imre Leader (Cambridge)  
13 Feb 2003  Harrison 106 Thursday 3pm  Pure Mathematics 
 
The application of the method of matched asymptotic expansions to problems arising in reactiondiffusion theory  
John Leach (University of Reading)  
10 Feb 2003  Harrison 170 Monday 2pm  Applied Mathematics 
 
RSS Local Group Meeting: The Forward Search and the Analysis of Multivariate Data  
Anthony Atkinson (London School of Economics)  
6 Feb 2003  Laver None None  Statistics & Operational Research 
See here for abstract  
 
Revisiting scaling laws for the magnetic and velocity fields  
Glenn Ierley (University of California San Diego)  
31 Jan 2003  Harrison 170 Monday 2pm  Applied Mathematics 
 
Mapping class groups and Teichmuller spaces  
William Harvey (King's College)  
30 Jan 2003  Harrison 106 Thursday 3pm  Pure Mathematics 
 
MarangoniBenard convection in square and almost square containers  
Edgar Knobloch (University of Leeds)  
27 Jan 2003  Harrison 170 Monday 2pm  Applied Mathematics 
 
Symmetric squares of elliptic curves: evidence for the BlochKato Conjecture  
Neil Dummigan (Sheffield)  
23 Jan 2003  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Instabilities of the Stewartson layer  
Rainer Hollerbach (University of Glasgow)  
20 Jan 2003  Harrison 170 Monday 2pm  Applied Mathematics 
 
Free Lie algebras as modules for finite groups  
Ralph Stohr (UMIST)  
16 Jan 2003  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Operational Research Seminar: An Overview of OR in Sport  
Chris Potts (University of Southampton)  
16 Jan 2003  Laver None None  Statistics & Operational Research 
This talk reviews some contributions that operational research (OR) has made in sport. The contributions roughly fall within the areas of planning and strategy, scheduling, ranking and performance measurement, and prediction. In planning and strategy, we discuss the use of dynamic programming for optimising batting strategies in oneday cricket, and describe how pit stop strategies are determined in formula one motor racing. For scheduling sports fixtures, we indicate how OR has been used in county cricket. Different sports use different methods for measuring the performance of players/teams. We comment briefly on the need for more robust systems. Finally, prediction is important for bookmakers and is of interest to sports enthusiasts. The modelling of the results of soccer games is discussed.  
 
Transient vortex events in turbulence  
Bob Kerr (University of Warwick)  
13 Jan 2003  Harrison 170 Monday 2pm  Applied Mathematics 
 
Zonal flows on Jupiter  
Chris Jones (University of Exeter)  
13 Dec 2002  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Postgraduate Seminar: Clustering Gene Expression Data  
Heather Turner (University of Exeter)  
12 Dec 2002  Laver None None  Statistics & Operational Research 
Gene expression data, resulting from the relatively new microarray technology, has many features which make it difficult to analyse. Many traditional techniques fail due to the size of the data sets or the lack of conformity to common assumptions, such as normality or independence.Clustering has proven to be a useful method of discovering functional grouping of genes, one of the main objectives of microarray experiments. A number of clustering algorithms have been specifically developed for gene expression data, designed to be more efficient and more flexible than standard algorithms. Tne of these algorithms is the plaid model, a twoway overlapping clustering method proposed by Lazzeroni and Owen (2002). This talk introduces the plaid model and proposes an alternative optimisation algorithm that may improve its efficiency. Possible extensions of the model will also be discussed.  
 
New observational constraints on the geodynamo  
Richard Holme (University of Liverpool)  
9 Dec 2002  Harrison 170 Monday 2pm  Applied Mathematics 
 
Geometric approach to the distribution of n**2 alpha mod 1  
Jens Marklof (Bristol)  
5 Dec 2002  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Functorial aspects of the unit sum number of rings  
Nahid Ashrafi (University of Exeter)  
4 Dec 2002  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
RSS Local Group Meeting: Predicting Reliability for Orthopaedic Hip Replacements  
Simon Wilson (Trinity College Dublin & Carlos III University Madrid)  
4 Dec 2002  Laver None None  Statistics & Operational Research 
See here for abstract  
 
Nature of torsional oscillations in the solar convection zone  
Reza Tavakol ('Queen Mary, University of London')  
2 Dec 2002  Harrison 170 Monday 2pm  Applied Mathematics 
 
Topological invariants for quasicrystals  
John Hunton (Leicester)  
28 Nov 2002  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Totally and weakly ramified extensions  
Lee Jackson (University of Exeter)  
27 Nov 2002  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Some bifurcation results for differentialalgebraic equations  
Robert Beardmore (Imperial College)  
25 Nov 2002  Harrison 170 Monday 2pm  Applied Mathematics 
 
Iwasawa algebras and arithmetic  
John Coates (Cambridge)  
21 Nov 2002  Harrison 106 Thursday 3pm  Pure Mathematics 
 
RSS Local Group Meeting: Challenges in Bioinformatics for Statisticians  
Wally Gilks ('MRC Biostatistics Unit, Cambridge')  
21 Nov 2002  Laver None None  Statistics & Operational Research 
See here for abstract  
 
A new proof of the uniqueness of elastic surface waves  
Yibin Fu (University of Keele)  
18 Nov 2002  Harrison 170 Monday 2pm  Applied Mathematics 
 
NonAbelian Iwasawa Theory and Elliptic Curves, Theory and Examples  
Susan Howson (Oxford)  
14 Nov 2002  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Simple groups and HopfGalois structures  
Nigel Byott (University of Exeter)  
13 Nov 2002  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Validity of various approximations of the fullycompressible atmospheric equation as inferred from normalmode analysis  
'Andrew Staniforth, Terry Davies and Nigel Wood' (Met Office)  
11 Nov 2002  Harrison 170 Monday 2pm  Applied Mathematics 
 
Topological Hochschild cohomology of noncommutative ring spectra  
Andrey Lazarev (Bristol)  
7 Nov 2002  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Statistics Seminar: Denoising real data using complex wavelets  
Stuart Barber (University of Bristol)  
7 Nov 2002  Laver None None  Statistics & Operational Research 
Wavelet shrinkage is an effective nonparametric regression technique when the underlying curve has irregular features such as spikes or discontinuities. The basic idea is simple: take the discrete wavelet transform (DWT) of data consisting of a signal corrupted by noise; shrink the wavelet coefficients to remove the noise; and then invert the DWT to form an estimate of the true underlying curve. Various authors have proposed methods of doing this using realvalued wavelets. Complexvalued versions of some wavelets exist, but are rarely used. We propose two shrinkage techniques which use complex wavelets. Simulation results show that both methods give smaller errors than using state of the art shrinkage rules with realvalued wavelets.  
 
Magnetic fields in barred galaxies  
David Moss (University of Manchester)  
4 Nov 2002  Harrison 170 Monday 2pm  Applied Mathematics 
 
Magnetic damping of surface gravity waves  
Binod Sreenivasan (University of Exeter)  
1 Nov 2002  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Starks conjecture and new Stickelberger phenomena  
Vic Snaith (Southampton)  
31 Oct 2002  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Commuting superline maps  
Ben Mestel (University of Exeter)  
30 Oct 2002  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Statistics Seminar: Bayesian rule based classification  
Chris Holmes (Imperial College London)  
30 Oct 2002  Laver None None  Statistics & Operational Research 
We describe a new method for statistical pattern recognition that is based on probabilistic rule sets. The model constructs a set of firstorder rules of the form IF A THEN B where the antecedent A relates to conditions on a set of predictor measurements x and the consequence B relates to changes in the odds function of the conditional probability p(y/x) for a category label y. Ruleset models are highly expressive and interpretable and a key feature of the method is the ease by which expert domain knowledge can be incorporated into the classifier system. A Bayesian framework is used which places a prior distribution over the state space of all probabilistic rule sets. Inference proceeds using stochastic simulation via tailored Markov chain Monte Carlo algorithms. The methodology is illustrated using examples taken from the machine learning literature where typically we have tens or hundreds of predictors and hundreds or thousands of observations.  
 
Virial functional in fluid mechanics  
Vladimir Vladimirov (Univeristy of Hull)  
28 Oct 2002  Harrison 170 Monday 2pm  Applied Mathematics 
 
Random matrix theory and Lfunctions  
Jon Keating (Bristol)  
24 Oct 2002  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Operational Research Seminar: Inventory  too much , too little, or right on?  
Geoff Relph (Manchester Business School)  
24 Oct 2002  Laver None None  Statistics & Operational Research 
Inventory has a major impact on business performance. How do you achieve that elusive balance  customer satisfaction and lower inventory? This talk examines some of the issues involved in better inventory planning. The concept of 'overage inventory' is defined and developed. Case research on inventory management in a manufacturing company is discussed. Options for evaluating and estimating the value of overage and determining simple prioritisation techniques for the desired corrective action needed to reduce the overage are examined. The pragmatic balance between purist academic views of inventory management and the instinctive approach often used in a small business are considered.  
 
Impulse differential inclusions: Towards a viability theory of hybrid systems  
John Lygeros (University of Cambridge)  
21 Oct 2002  Harrison 170 Monday 2pm  Applied Mathematics 
 
A new test for chaos in deterministic nonlinear dynamical systems  
Ian Melbourne (University of Surrey)  
14 Oct 2002  Harrison 170 Monday 2pm  Applied Mathematics 
 
Mixing and Diophantine problems  
Tom Ward (UEA)  
10 Oct 2002  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Fractal asymptotics  
Carl Dettmann (University of Bristol)  
7 Oct 2002  Harrison 170 Monday 2pm  Applied Mathematics 
 
Counting subgroups in nilpotent groups and points on elliptic curves  
Marcus du Sautoy (Oxford)  
18 Jun 2002  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Complex and padic Stark Conjectures at s=1  
David Solomon (Kings College)  
13 Jun 2002  Harrison 106 Thursday 3pm  Pure Mathematics 
 
On the relationship between the discrete and continuous Painleve equations  
Peter Clarkson (University of Kent)  
10 Jun 2002  Harrison 170 Monday 2pm  Applied Mathematics 
 
'Invariant extension of automorphic functions, differential intertwining operators and Jacobi polynomials'  
Andreas Juhl (Stockholm)  
6 Jun 2002  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Conformal geometry and Clifford algebras  
Fran Burstall (Bath)  
30 May 2002  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Explicitly timedependent alphaquenching  
Axel Brandenburgh (NORDITA)  
27 May 2002  Harrison 170 Monday 2pm  Applied Mathematics 
 
The Hasse principle for Diophantine equations  
Alexei Skorobogatov (Imperial)  
23 May 2002  Harrison 106 Thursday 3pm  Pure Mathematics 
 
RSS Local Group Meeting: Does the weather God play dice?  
David Stephenson (University of Reading)  
23 May 2002  Laver None None  Statistics & Operational Research 
See here for abstract  
 
Higher power residue codes and unimodular lattices  
Mehrdad AhmadzadehRaji (University of Exeter)  
21 May 2002  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Galois covers of degree p and semistable reduction of curves  
Mohamed Saďdi (Durham)  
16 May 2002  Harrison 106 Thursday 3pm  Pure Mathematics 
 
RSS Local Group Meeting & AGM: Something in the air? Multivariate analysis and atmospheric science  
Ian Jolliffe (University of Aberdeen)  
16 May 2002  Laver None None  Statistics & Operational Research 
See here for abstract  
 
Stochastic population dynamics  
Xuerong Mao (University of Strathclyde)  
13 May 2002  Harrison 170 Monday 2pm  Applied Mathematics 
 
New quadratic iterations to Pi  
Heng Huat Chan (National U Singapore)  
9 May 2002  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Constructing Hopf orders to act on valuation rings  
Julie Fowler (University of Exeter)  
7 May 2002  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Pisot numbers and Coxeter graphs  
Chris Smyth (Edinburgh)  
2 May 2002  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Operational Research Seminar: Base stock inventory policies  
Mundappa Pakkala (University of Mangalore)  
2 May 2002  Laver None None  Statistics & Operational Research 
We consider an inventory model in continuous time. Demand follows a Poisson process and demand during a stockout is backordered. The stock level is controlled by means of a base stock policy in which the balance of physical stock plus stock on order less backorders is maintained at the base stock level. Therefore if a demand occurs then an order for replacement stock is placed immediately. The time for a replacement order to arrive is the lead time  this may be fixed or it may vary. We consider here two variants on this basic policy. First, multiitem demand processes. Second, modelling the cash flows. In each case we discuss the context of the problem, its mathematical formulation and a procedure for finding the optimal solution.  
 
Quantum monodromy  
Holger Dullin (Loughborough University)  
29 Apr 2002  Harrison 170 Monday 2pm  Applied Mathematics 
 
The Kubota symbol on SL_n  
Richard Hill (UCL)  
25 Apr 2002  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Composition convection due to the decrease of the rapidly rotating shell  
Serguey Starchenko (GFO Borok)  
22 Apr 2002  Harrison 170 Monday 2pm  Applied Mathematics 
 
'Paperfolding, automata, and rational functions'  
Alf van der Poorten (Sydney)  
14 Mar 2002  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Operational Research Seminar: Locating ambulances in Riyadh: theoretical developments and practical application  
Graham Rand (University of Lancaster)  
14 Mar 2002  Laver None None  Statistics & Operational Research 
The location of Emegency Medical Services (EMS) is an important problem. Good locations, enabling rapid response, can save lives. Typical OR modelling for these problems tries to improve coverage which is defined as the ability to travel from a service station to a demand point in a prespecified time. A model was developed to evaluate locations for the Saudi Arabian Red Crescent Society (SARCS), Riyadh City, Saudi Arabia. In this model the usual 01 coverage definition (i.e. the demand is covered or not) is replaced by the probability of covering a demand within the target time. Second, once the locations are determined, the minimum number of vehicles at each location that satisfies the required performance levels is determined. Thus, the problem of identifying the optimal locations of a prespecified number of emergency medical service (EMS) stations is addressed by goal programming. The first goal is to locate these stations so the maximum expected demand can be reached within a prespecified target time. Then, the second goal is to ensure that any demand arising located within the service area of the station will find at least one vehicle, such as an ambulance, available. Erlang's loss formula is used to identify the arrival rates when it is necessary to add an ambulance in order to maintain the performance level for the availability of ambulances. The use of the model for the Riyadh EMS will be described. This work was undertaken jointly with Othman Alsalloum  
 
Determining matroid representability over the reals  
Rosemary Baines (University of Exeter)  
12 Mar 2002  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Shear and magnetic buoyancy instabilities in the solar tachocline  
Steve Tobias (University of Leeds)  
11 Mar 2002  Harrison 170 Monday 2pm  Applied Mathematics 
 
Beyond BorelCantelli  
Maurice Dodson (York)  
7 Mar 2002  Harrison 106 Thursday 3pm  Pure Mathematics 
 
On the matrix type of a ring  
Rahman BahmaniSangesari (University of Exeter)  
5 Mar 2002  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Vortex equilibria of the Euler equations  
Darren Crowdy (Imperial College)  
4 Mar 2002  Harrison 170 Monday 2pm  Applied Mathematics 
 
RSS Local Group Meeting: Inference in fMRI experiments using spectral domain methods  
Jonathan Marchini (University of Oxford)  
28 Feb 2002  Laver None None  Statistics & Operational Research 
See here for abstract  
 
Torsion theory and coCohenMacaulay modules  
Mohammad BijanZadeh (University of Tehran)  
26 Feb 2002  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Thin layer theories  
Richard Craster (Imperial College)  
25 Feb 2002  Harrison 170 Monday 2pm  Applied Mathematics 
 
Polylogarithms and special values of Lfunctions  
Guido Kings (Regensburg)  
21 Feb 2002  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Postgraduate Seminar: Lot sizing policies in an advance ordering environment  
Lynette Frick (University of Exeter)  
21 Feb 2002  Laver None None  Statistics & Operational Research 
In most classic inventory models customer demand is either assumed to be deterministic or stochastic. In some multiperiod applications, future demand is only  
 
Localisation of patterns in convection  
Stephen Cox (University of Nottingham)  
18 Feb 2002  Harrison 170 Monday 2pm  Applied Mathematics 
 
Homology decompositions of classifying spaces  
Dietrich Notbohm (Leicester)  
14 Feb 2002  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Statistics Seminar: Disease mapping of stagespecific cancer incidence data  
Leo KnorrHeld (University of Lancaster)  
14 Feb 2002  Laver None None  Statistics & Operational Research 
We propose two approaches for the spatial analysis of cancer incidence data with additional information on the stage of the disease at time of diagnosis. The two formulations are extensions of commonly used models for multicategorical response data on an ordinal scale. We include spatial and age group effects in both formulations, which we estimate in a nonparametric smooth way. More specifically, we adopt a fully Bayesian approach based on Gaussian pairwise difference priors where additional smoothing parameters are treated as unknown as well. We argue that the proposed methods are useful in monitoring the effectiveness of mass cancer screening and illustrate this through an application to data on cervical cancer in the former German Democratic Republic. The results suggest that there are large spatial differences in the stageproportions, which indicates spatial variability with respect to the introduction and effectiveness of pap smear screening programs. This is joint work with G Rasser, University of Munich and N Becker, German Cancer Research Center Heidelberg.  
 
Pattern selection and symmetry in rotating RayleighBenard convection  
Jon Dawes (University of Cambridge)  
11 Feb 2002  Harrison 170 Monday 2pm  Applied Mathematics 
 
Local analogue of the Grothendieck Conjecture  
Victor Abrashkin (Durham)  
7 Feb 2002  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Statistics Seminar: Crossvalidation in additive main effect and multiplicative interaction (AMMI) models  
Carlos Tadeu dos Santos Dias (University of Sao Paulo/ESALQ)  
7 Feb 2002  Laver None None  Statistics & Operational Research 
The additive main effects and multiplicative interaction (AMMI) model has been proposed for the analysis of genotype/environmental data. For plant breeding, the recovery of pattern might be considered to be the principal objective of analysis. However, some problems still remain with the analysis, notably in selecting the number of multiplicative components in the model. Methods based on distributional assumptions do not have sound methodological basis, while existing databased approaches do not optimise the crossvalidation process. This talk will first summarise the AMMI model and outline the available methodology for selecting the number of multiplicative components to include in it. Then two new methods will be described that are based on a full leaveoneout procedure optimising the crossvalidation process. Both methods will be illustrated and compared on some unstructured multivariate data. Finally, their application to analysis of GxE interaction will be demonstrated on experimental grain yield data.  
 
Realisable classes of wild extensions  
Lee Jackson (University of Exeter)  
5 Feb 2002  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
The role of the heating mode of the mantle in intermittent reorganisation of plate velocities  
Julian Lowman (University of Leeds)  
4 Feb 2002  Harrison 170 Monday 2pm  Applied Mathematics 
 
Rings generated by Eulerian derivatives  
David Jordan (Sheffield)  
31 Jan 2002  Harrison 106 Thursday 3pm  Pure Mathematics 
 
On globally periodic solutions of the difference equation $x_{n+1} = f(x_n)/x_{n1}$  
Ben Mestel (University of Exeter)  
29 Jan 2002  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
MHD in metallurgical processes  
Peter Davidson (University of Cambridge)  
28 Jan 2002  Harrison 170 Monday 2pm  Applied Mathematics 
 
'Ergodic averages, exponential sums and combinatorial number theory'  
Kit Nair (Liverpool)  
24 Jan 2002  Harrison 106 Thursday 3pm  Pure Mathematics 
 
RSS Local Group Meeting: Anticipating catastrophes through extereme value modelling  
Stuart Coles (University of Bristol)  
24 Jan 2002  Laver None None  Statistics & Operational Research 
See here for abstract  
 
Fast dynamo problem  
Oleg Kozlovski (University of Warwick)  
21 Jan 2002  Harrison 170 Monday 2pm  Applied Mathematics 
 
The Fermat equation over real quadratic fields  
Frazer Jarvis (Sheffield)  
17 Jan 2002  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Statistics Seminar: Geostatistical models and applications  
Paulo Ribeiro (University of Lancaster)  
17 Jan 2002  Laver None None  Statistics & Operational Research 
The term 'geostatistics' identifies the part of spatial statistics which is concerned with continuous spatial variation. The term 'modelbased geostatistics' was coined by Diggle, Tawn and Moyeed (1998) to mean the application of explicit parametric, stochastic models and formal, likelihoodbased, methods of inference to geostatistical problems. Geostatistical methods are currently applied in a wide range of subjects and modelbased methods provide further options to tackle challenging pratical problems. Motivated by some pratical applications, this talk discusses modelbased geostatistical methods and their computational implementation.  
 
Jets, waves and vortices in the Jovian atmosphere POSTPONED  
Yasuhiro Yamazaki (University of Oxford)  
14 Jan 2002  Harrison 170 Monday 2pm  Applied Mathematics 
 
Operational Research Seminar: A bounding problem in inventory modelling  
Roger Hill (University of Exeter)  
10 Jan 2002  Laver None None  Statistics & Operational Research 
A fundamental inventory model is the stochastic demand, periodic or continuous review, backorder model with linear holding, shortage and ordering costs and a general lead time on replenishment. It is wellestablished that the optimal control policy for this model is an (s,S) policy and efficient procedures exist for deriving this optimal policy. An important feature of most practical systems is that packaging and handling considerations require that replenishments must be in multiples of some unit of stock transfer q. This talk describes, in outline, the fundamental model and shows how the analysis can be adapted to allow for a general unit of stock transfer q. It finally raises some, as yet unresolved, issues on developing procedures for finding the optimal policy for this modified model.  
 
Deterministic and random products of Euclidean transformations CANCELLED  
Ian Melbourne (University of Surrey)  
7 Jan 2002  Harrison 170 Monday 2pm  Applied Mathematics 
 
Global bifurcation to travelling waves in spherical Couette flow  
Andrew Soward (University of Exeter)  
7 Dec 2001  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Goldbach's conjecture and powers of 2  
Roger HeathBrown (Oxford)  
6 Dec 2001  Harrison 106 Thursday 3pm  Pure Mathematics 
 
A golden mean functional recurrence  
Ben Mestel (University of Exeter)  
4 Dec 2001  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Adaptive controllers and the gap metric  
Mark French (University of Southampton)  
3 Dec 2001  Harrison 170 Monday 2pm  Applied Mathematics 
 
A new generation of geodynamo models  
Keke Zhang (University of Exeter)  
30 Nov 2001  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Lower and Upper Bounds in Discrepancy Theory  
William Chen ('Macquarie University, Sydney')  
29 Nov 2001  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Analysis of transplant survival rates  
Dave Collett (University of Reading)  
28 Nov 2001  Laver None None  Statistics & Operational Research 
 
Realisable classes for tame nonabelian extensions of degree 8  
Nigel Byott (University of Exeter)  
27 Nov 2001  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Oscillations in small aspect ratio magnetoconvection  
Mike Proctor (University of Cambridge)  
26 Nov 2001  Harrison 170 Monday 2pm  Applied Mathematics 
 
Nonlinear models of rotating spherical convection  
Steve Cole (University of Exeter)  
23 Nov 2001  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Schur Weyl duality and tilting theory  
Steffen Koenig (Leicester)  
22 Nov 2001  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Should small firms be more cautious than large ones?  Dynamic programming models of operations management decisions in small firms.  
Lyn Thomas (University of Southampton)  
22 Nov 2001  Laver None None  Statistics & Operational Research 
Operations management models, like inventory control and production levels have proved very successful in the operations of firms. However they all take as their objective the maximisation of profit or the minimisation of cost. For small firms it could be argued that maximising the probability of survival of the firm is the principal objective. This talk looks at how one can model the operations management decisions under this criterion using dynamic programming and compares the survival probability maximising decisions with the profit maximising ones. It suggests that small firms should be more cautious ( but not too cautious) than large firms.  
 
A family of equivariant Fredholm modules  
Stuart Horswell (University of Exeter)  
20 Nov 2001  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Galactic magnetic fields  
Steven Cowley (Imperial College)  
19 Nov 2001  Harrison 170 Monday 2pm  Applied Mathematics 
 
Hopf bifurcation with the symmetry of the cube  
Pete Ashwin (University of Exeter)  
16 Nov 2001  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Do we really live in a Riemannian world?  
Dmitri Vassiliev (Bath)  
15 Nov 2001  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Postgraduate Seminar: Statistical modelling of performance indicators  
Paul Hewson (University of Exeter)  
15 Nov 2001  Laver None None  Statistics & Operational Research 
Performance Indicators are amongst the most widely published official statistics in the UK. It has been suggested that the UK central government has set over 5,000 targets against these statistics. In contrast to the wealth of numerical data available, less effort has been applied to the statistical analysis of the data. Most work performed to date has been in the educational and health fields, although considerable money has been spent evaluating data envelopment analysis for the Home Office to develop targets for police performance. Using two sets of Performance Indicators, relating to Housing Benefit Administration and Road Safety (reflecting output and outcome indicators), various methods for analysis will be reviewed, particularly approaches based upon generalised linear mixed models. Work in progress to account for the multivariate nature of the data in such models will also be described.  
 
A probabilistic proof of the AndrewsGordon identities  
Robin Chapman (University of Exeter)  
13 Nov 2001  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Particles in a random field  
Andrew Stuart (University of Warick)  
12 Nov 2001  Harrison 170 Monday 2pm  Applied Mathematics 
 
Some issues in stochastic control  
Stuart Townley (University of Exeter)  
9 Nov 2001  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Transversals in Latin Squares  
Ian Wanless (Oxford)  
8 Nov 2001  Harrison 106 Thursday 3pm  Pure Mathematics 
 
RSS Meeting: Modelling spatialtemporal processes for hydrology and climate  
Valerie Isham (University College London)  
7 Nov 2001  Laver None None  Statistics & Operational Research 
A review will be given of some of the spatialtemporal models developed by an interdisciplinary team from University College and Imperial College for use in the context of hydrological design. Approaches using both pointprocessbased stochastic models and statistical, generalised linear, models (GLMs) will be described. A strength of the former models is their ability to represent high spacetime resolution, while the latter more easily enable spatial and temporal nonstationarities to be incorporated. These models are also being used to investigate other climatological processes, such as temperature and wind speed, where there is a particular focus on questions of the influence of longrange effects (e.g., El Nino), and climate change.  
 
Endomorphisms of free modules of infinite rank  
Peter V'{a}mos (University of Exeter)  
6 Nov 2001  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Shear propagation into the solar radiative zone  
Pascale Garaud (University of Cambridge)  
5 Nov 2001  Harrison 170 Monday 2pm  Applied Mathematics 
 
Energy fluxes and dissipation in planetary cores  
Chris Jones (University of Exeter)  
2 Nov 2001  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Statistics, symmetry and skew products  
Mike Field (University of Houston)  
29 Oct 2001  Harrison 170 Monday 2pm  Applied Mathematics 
 
Vorticity, mixing and motion  
Andrew Gilbert (University of Exeter)  
26 Oct 2001  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Probability and learning  
Igor Rivin (Manchester)  
25 Oct 2001  Harrison 106 Thursday 3pm  Pure Mathematics 
 
RSS Meeting: Bayes 'n' drugs 'n' sporting role  
Phil Brown (University of Kent)  
25 Oct 2001  Laver None None  Statistics & Operational Research 
A joint EU/IOC international project centered on St. Thomas's Hospital London has been looking at detection of growth hormone abuse in sport. We describe approaches to modelling multivariate markers of GH intake through time to discriminate between those that were treated with growth hormone and those on placebo in a doubleblind study.  
 
Mellin transforms of Whittaker functions  
Anton Deitmar (University of Exeter)  
23 Oct 2001  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Kinematic dynamos at high magnetic Reynolds number  
Graeme Sarson (University of Newcastle upon Tyne)  
22 Oct 2001  Harrison 170 Monday 2pm  Applied Mathematics 
 
Scaling properties of spatial and temporal spectra of the geomagnetic field  
Roberta Tozzi (Rome)  
19 Oct 2001  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Rings of injective dimension 1  
Arthur Chatters (Bristol)  
18 Oct 2001  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Estimating abundance from data containing many zeros  
Alan Welsh (University of Southampton)  
18 Oct 2001  Laver None None  Statistics & Operational Research 
North East Herald Cay is a small but ecologically significant coral cay in the Coral Sea, about 350 km off the coast of Queensland, Australia. As part of the development of a monitoring program, we consider the problem of estimating the number of nests of different species of seabirds on North East Herald Cay based on surveys of 10mx10m quadrats along transects across the Cay. We consider three approaches based on different plausible models. Our main findings are that an approach based on a conditional negative binomial model which allows for additional zeros in the data works well and that a transformbothsides regression approach produces badly biased estimates and should not be used. We discuss our experience of collecting the data, applying the methodology to the available data and discuss the implications for monitoring nesting on North East Herald Cay.  
 
Saturating MordellWeil groups  
John Cremona (Nottingham)  
11 Oct 2001  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Statistics in sport and games  
Frank Duckworth ('Editor, RSS News')  
10 Oct 2001  Laver None None  Statistics & Operational Research 
 
Weak disjointness in topological dynamics  
Xiangdong Ye (University of Science and Technology of China)  
25 Sep 2001  Harrison 170 Monday 2pm  Applied Mathematics 
 
Are there any (interesting) noncommutative Hopf orders?  
Nigel Byott (University of Exeter)  
26 Jun 2001  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
From matroids to equations and back  
Peter Vamos (University of Exeter)  
19 Jun 2001  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Numerical modelling of star formation  
Matthew Bate (University of Exeter (Physics))  
15 Jun 2001  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Families of modular forms  
Kevin Buzzard (Imperial College)  
14 Jun 2001  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Packing properties of invariant disks for some planar piecewise isometries  
XinChu Fu (University of Exeter)  
8 Jun 2001  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Generalizing the analytic class number formula  
Annette HuberKlawitter (Leipzig)  
7 Jun 2001  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Quantum turbulence in superfluid helium  
Tomasz Lipniacki (University of Warsaw)  
1 Jun 2001  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Quantisations of Kleinian Singularities and Beyond  
Dmitriy Rumynin (Warwick)  
31 May 2001  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Special RSS Meeting and AGM at Plymouth University (Robbins Seminar Room 2): A Heretic's View of Placebos and Ethics in Clinical Trials  
Stephen Senn ('University College, London')  
31 May 2001  Laver None None  Statistics & Operational Research 
 
Evolution of sharp edged planar vortices  
Ian Hall (University of Exeter)  
25 May 2001  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Refined class number formulas for abelian Lfunctions  
David Burns (King's College)  
24 May 2001  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Postgraduate Seminar: Using State Space models to investigate the effect of vitamin A supplement on diarrhoea  
Valeska Andreozzi (University of Exeter)  
24 May 2001  Laver None None  Statistics & Operational Research 
 
Postgraduate Seminar: A Score Test for Zeroinflated Negative Binomial Models  
Naratip Jansakul (University of Exeter)  
24 May 2001  Laver None None  Statistics & Operational Research 
 
Lefschetz formulae for dynamical systems  
Anton Deitmar (University of Exeter)  
22 May 2001  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Routes to chaos, channel capacity and the representation of numbers in noninteger bases'  
Paul Glendinning (UMIST)  
21 May 2001  Harrison 170 Monday 2pm  Applied Mathematics 
 
Instabilities induced by the differentially rotating inner core and mantle  
Pu Zhang (University of Exeter)  
18 May 2001  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Principal homogeneous spaces for some Hopf orders  
Silvia Sommaro (University of Exeter)  
15 May 2001  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Chaotic Dynamics in Semiconductor Lasers  
Pieter Collins (University of Liverpool)  
14 May 2001  Harrison 170 Monday 2pm  Applied Mathematics 
 
Fourier series on spheres  
Paul Earnshaw (University of Exeter)  
11 May 2001  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Bending Kleinian Groups  
Caroline Series (Warwick)  
10 May 2001  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Invariant distributions on limit sets  
Martin Olbrich (Goettingen)  
3 May 2001  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Bizarre qseries identities  
Robin Chapman (University of Exeter)  
1 May 2001  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
One hundred years of normal numbers  
Glyn Harman (Royal Holloway)  
26 Apr 2001  Harrison 106 Thursday 3pm  Pure Mathematics 
 
'Numerical exterior algebra, with applications in hydrodynamic stability and dynamical systems'  
Tom Bridges (University of Surrey)  
23 Apr 2001  Harrison 170 Monday 2pm  Applied Mathematics 
 
The size of orders from customers, characterisation, forecasting and implications  
Roy Johnston (Warwick University)  
18 Apr 2001  Laver None None  Statistics & Operational Research 
 
Dynamics of a SigmaDelta modulator as a piecewise isometry  
Jonathan Deane (University of Surrey)  
30 Mar 2001  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
The 200th proof of quadratic reciprocity?  
Robin Chapman (University of Exeter)  
20 Mar 2001  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Using the Randomisation in Specifying the Mixed Models and ANOVA tables  
Chris Brien (University of South Australia)  
16 Mar 2001  Laver None None  Statistics & Operational Research 
 
Symmetric powers of Galois modules  
Bernhard Koeck (University of Southampton)  
15 Mar 2001  Harrison 106 Thursday 3pm  Pure Mathematics 
 
'Typical magnetoconvection values in the interiors of Jupiter, Saturn and the Earth'  
Sergey Starchenko ('GFO Barok, Russia')  
13 Mar 2001  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Galois Module Structure of some nonnormal extensions (of padic fields)  
Julie Fowler (University of Exeter)  
13 Mar 2001  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Modulating pulse solutions for a class of nonlinear wave equations  
Mark Groves (University of Loughborough)  
12 Mar 2001  Harrison 170 Monday 2pm  Applied Mathematics 
 
MHD shear layers in spherical Couette flow  
Andrew Soward (University of Exeter)  
9 Mar 2001  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Rings having finite unit sum number  
Nahid Ashrafi (University of Exeter)  
8 Mar 2001  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Postgraduate Seminar: Analysis of Multivariate Process Control Data  
Julie Badcock (University of Exeter)  
8 Mar 2001  Laver None None  Statistics & Operational Research 
 
Postgraduate Seminar:The Evolution of Trees: Application of Genetic Algorithms to Network Optimisation  
Evan Thompson (University of Exeter)  
8 Mar 2001  Laver None None  Statistics & Operational Research 
 
Derangements and (0,1) matrices with line sum 2  
Douglas Rogers  
6 Mar 2001  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Stochastic bifurcation: concepts and examples  
Ludwig Arnold ('Universitat Bremen')  
5 Mar 2001  Harrison 170 Monday 2pm  Applied Mathematics 
Part of the %http://www.maths.ex.ac.uk/Research/applDSC/events/ndc.html%Southern Bifurcation Meeting%  
 
Quasiinvariant sets in Piecewise Isometries  
Miguel Mendes (University of Surrey)  
2 Mar 2001  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Characteristic classes of surface bundles  
Ulrike Tillmann (University of Oxford)  
1 Mar 2001  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Use of discrete event simulation in the evaluation of screening for Helicobacter pylori for the prevention of peptic ulcers and gastric cancer.  
Ruth Davis (University of Southampton)  
1 Mar 2001  Laver None None  Statistics & Operational Research 
 
Higher power residue codes and the Leech lattice  
Mehrdad AhmadzadehRaji (University of Exeter)  
27 Feb 2001  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Neutral Rayleigh waves in HagenPoiseuille flow  
Andrew Walton (Imperial College)  
26 Feb 2001  Harrison 170 Monday 2pm  Applied Mathematics 
 
Nonorientable manifolds in threedimensional vector fields  
Hinke Osinga (University of Exeter)  
23 Feb 2001  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Prehomogeneous vector spaces and the trace formula  
Werner Hoffman (University of Berlin)  
22 Feb 2001  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Almost Unique Factorisation Domains  
Peter V'{a}mos (University of Exeter)  
20 Feb 2001  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Receptivity of boundary layers to freestream disturbances  
Paul Hammerton (University of East Anglia)  
19 Feb 2001  Harrison 170 Monday 2pm  Applied Mathematics 
 
Convection in a semiinfinite layer above a flat plate  
Andrew Bassom (University of Exeter)  
16 Feb 2001  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Probabilistic structures in Dynamics  
Stefano Luzatto (Imperial College)  
15 Feb 2001  Harrison 106 Thursday 3pm  Pure Mathematics 
 
RSS meeting: Estimating Mixtures of Regressions  
Merrilee Hurn (University of Bath)  
15 Feb 2001  Laver None None  Statistics & Operational Research 
 
Crystallographic groups and Milnor's conjecture  
Dietrich Burde (Dusseldorf)  
13 Feb 2001  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
'Dynamo action in the stretch, fold, shear model'  
Andrew Gilbert (University of Exeter)  
9 Feb 2001  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Cyclic homology and the BaumConnes conjecture  
Michael Puschnigg (University of Munster)  
8 Feb 2001  Harrison 106 Thursday 3pm  Pure Mathematics 
 
KrullSchmidt theorem, Goldie dimensions and uniserial modules  
Alberto Facchini (University of Padua)  
6 Feb 2001  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
The magnetorotational instability in a Couettetype flow  
Wolfgang Dobler (University of Newcastle upon Tyne)  
5 Feb 2001  Harrison 170 Monday 2pm  Applied Mathematics 
 
The anatomy of some nonholonomic oscillators  
Ciprian Coman (University of Exeter)  
2 Feb 2001  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
The matrix group recognition project  
Charles LeedhamGreen (QMW)  
1 Feb 2001  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Class numbers of cubic orders  
Anton Deitmar (University of Exeter)  
30 Jan 2001  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Rotational instabilities of contained fluids; laboratory experiments and applications to the Earth's core  
Keith Aldridge (York University, Canada)  
29 Jan 2001  Harrison 170 Monday 2pm  Applied Mathematics 
 
Rational Points Close to Curves  
Martin Huxley (University of Cardiff)  
25 Jan 2001  Harrison 106 Thursday 3pm  Pure Mathematics 
 
RSS meeting: Independent component analysis: flexible sources and nonstationary mixing  
Richard Everson (University of Exeter (Computer Science))  
25 Jan 2001  Laver None None  Statistics & Operational Research 
 
A contraction mapping proof of Schroeder's theorem  
Ben Mestel (University of Exeter)  
23 Jan 2001  Harrison 103 Tuesday None  Pure Mathematics (Internal) 
 
Using constrained variational techniques to improve numerical weather prediction  
Ian Roulstone (University of Reading)  
22 Jan 2001  Harrison 170 Monday 2pm  Applied Mathematics 
 
Bifurcations in nonlinear dynamos driven by ABC forcing  
Olga Podvigina (University of Moscow)  
19 Jan 2001  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Symmetric group representations  
Gordon James (Imperial College)  
18 Jan 2001  Harrison 106 Thursday 3pm  Pure Mathematics 
 
%http://www.maths.ex.ac.uk/~PAshwin/workshop_15_1_01.html%Dynamics and Intermittency%  
(WORKSHOP)  
15 Jan 2001  Harrison 170 Monday 2pm  Applied Mathematics 
 
Multiscale spaceperiodic kinematic dynamos  
Vlad Zheligovsky (University of Moscow)  
12 Jan 2001  Harrison 106 Wednesday 3pm  Applied Mathematics (Internal) 
 
Integration on nonlocally compact spaces and local Lfunctions of arithmetic schemes  
Ivan Fesenko (University of Nottingham)  
11 Jan 2001  Harrison 106 Thursday 3pm  Pure Mathematics 
 
Is intermittency that nonlinear?  
Sergei Nazarenko (University of Warwick)  
8 Jan 2001  Harrison 170 Monday 2pm  Applied Mathematics 
