Please note that the list below only shows forthcoming events, which may not include regular events that have not yet been entered for the forthcoming term. Please see the past events page for a list of all seminar series that the department has on offer.

 

Mon, 15 Aug 2022 09:30 -
Fri, 19 Aug 2022 15:00
L3

PDE WORKSHOP: Stability Analysis for Nonlinear PDEs

((Department of Mathematics)
Further Information

Monday 15th August

09:30     10:30     Morning Refreshments

10:30     11:20     Session 1: Mikhail Feldman

11:30     12:20     Session 2: Cleopatra Christoforou

12:30     14:30     Lunch Break

14:30     15:20     Session 3: Jiang-Lun Wu

 

Tuesday 16th August

09:30     10:30     Morning Refreshments

10:30     11:20     Session 4: Jonathan Ben-Artzi

11:30     12:20     Session 5: Mikhail Perepelita

12:30     14:30     Lunch Break

14:30     15:20     Session 6: Monica Torres

 

Wednesday 17th August

09:30     10:30     Morning Refreshments

10:30     11:20     Session 7: Aram Karakhanyan

11:30     12:20     Session 8: Piotr Gwiazda

12:30     14:30     Lunch Break

14:30     15:20     Session 9: Cheng Yu

15:30     16:20     Session 10: Steve Shkoller (UC-Davis, USA) [online]

 

Thursday

09:30     10:00     Morning Refreshments

10:00     10:50     Session 11: Susana Gutierrez

11:00     11:25     Session 12: Matthew Schrecker

11:30     12:00     Morning Break (30mins)

12:00     12:25     Session 13: Timon Salar Gutleb

12:30     12:55     Session 14: Yucong Huang

13:00     14:30     Conference Lunch (90mins)

14:30     15:20     Session 15: Nicolas Dirr

15:30     16:20     Session 16: Dehua Wang (U. Pittsburgh, USA) [online]

16:30     17:00     Afternoon Break (20mins)

17:00     17:50     Session 17: Pierre-Emmanuel Jabin (Penn State, USA) [online]

18:30     21:00     Conference Dinner

 

Friday

09:30   10:30   Morning Refreshments

10:30   11:20   Session 18: Ewelina Zatorska 

11:30   12:20   Session 19: Alexis Vasseur

12:30   12:45  Closing Remarks

13:00    ** **   Conference Lunch

 

Please note that registration has closed. Hard copies of the programme with speaker's titles and abstracts will be accessible to attendees from Monday 16th August.

 

Organisers: 

Prof. Gui-Qiang G. Chen

Prof. José A. Carrillo

Prof. Endre Süli

 

Administrator:

Charlotte Turner-Smith 

Sarah Randall

Abstract

Maths PNG

 

 

 

 

 

 

 

PDE Workshop in Stability Analysis for Nonlinear PDEs will be running Monday 15th - Friday 19th August.

Location: L3, AWB

Our goal is to bring together leading experts in the stability analysis of nonlinear partial differential equations across multi-scale applications. Some of the topics to be addressed include: 

  • Stability analysis of shock wave patterns of reflections/diffraction.
  • Stability analysis of vortex sheets, contact discontinuities, and other characteristic discontinuities for multidimensional hyperbolic systems of conservation laws.
  • Stability analysis of particle to continuum limits including the quantifying asymptotic/mean-field/large-time limits for pairwise interactions and particle limits for general interactions among multi-agent systems
  • Stability analysis of asymptotic limits with emphasis on the vanishing viscosity limit of solutions from multidimensional compressible viscous to inviscid flows with large initial data.

Preposed Schedule (Subject to changes)

Fri, 09 Sep 2022 09:30 -
Sat, 10 Sep 2022 17:30
Bodleian Weston Library

Imagining AI

Troy Astarte (Swansea); David Brock (Computer History Museum); Kanta Dihal (Cambridge); David Dunning (Pennsylvania); Sharon Ruston (Lancaster); and Máté Szabó (Oxford/Greenwich)
Further Information

Image from Charles Babbage's Passages from the life of a philosopher, London 1864.


EVENTS

Friday 9th September, 09.30-17.30, Workshop
Expert discussion of items from Oxford's collections and their  broader context: registration details here https://visit.bodleian.ox.ac.uk/event/sep22/imagining-ai-a-view-from-the-archive

The event will be chaired by Professor Ursula Martin of Wadham College and Oxford Mathematics.   Speakers include:

  • Troy Astarte (Swansea) on Christopher Strachey's 1950s experiments with computer poetry and chess
  • David Brock (Computer History Museum, Mountain View) on the curation of  AI experiments
  • Kanta Dihal (Cambridge) author of "AI Narratives" (OUP)
  • David Dunning (Pennsylvania) on Jevons's 1850s "Reasoning Piano"
  • Sharon Ruston (Lancaster) author of “The science of life and death in Frankenstein" (Bodleian)
  • Máté Szabó (Oxford, Greenwich) on Max Newman's influence on Alan Turing

A panel discussion chaired by Professor Rob Iliffe, Head of the Faculty of History, will explore how the history and philosophy of AI and computing can enrich contemporary conversations about the use of these transformative technologies

See titles, abstracts and more about our speakers here.


    Saturday 10 September, Imagining AI demonstrations with Oxford Open Doors

    Encounter a world of AI at the Weston Library. 

    Meet Ai-Da – booking essential, 11.00 – 12.00 Sir Victor Blank Lecture Theatre    Meet Ai-Da, the world’s first ultra-realistic robot artist, for a Q&A and live art session hosted by Cheney School’s Rumble Museum Council students.  If you have a question for Ai-Da please send it to @email  by Friday 27 August with the subject line ‘Question for Ai-Da’. More here 

    Encounter AI – drop-in 10.30 – 15.30  Blackwell Hall.  

    • See a steam-powered Difference Engine in action, designed by Charles Babbage and 3-D printed by a team at Royal Holloway University of London  More here
    • Discover a robot ladybug that responds to light and sound, courtesy of the John von Neumann Computer Society. More here
    • Students from Cheney School will exhibit artwork and creative writing responding to artificial intelligence in our lives today and in the future.
    • Ai-Da will be in Blackwell Hall 13.30 – 15.30 for photographs only.

    DISPLAYS OPENING 9th SEPTEMBER

    Blackwell Hall, Weston Library  Explore the ideas that led to contemporary AI  with manuscripts of computer pioneer Ada Lovelace; pages from Mary Shelley's draft of "Frankenstein", and notes on computer poetry and draughts from Turing's collaborator Christopher Strachey. The History of Science Museum are lending Stanley Jevons's remarkable mechanical “reasoning piano” from the 1860s, and an even earlier pocket logic calculator.

    History of Science Museum See the earliest plans and prototypes of Charles Babbage's computers, and Ada Lovelace's so-called "first programme".


    OTHER

    13th June and afterwards online, Meet the machines Sharon Ruston and Ursula Martin take a closer look at manuscripts of Mary Shelley, Humphry Davy and Ada Lovelace. Online link to follow.

    cs4fn magazine  Cunning Computational Contraptions: Issue 28 of the cs4fn magazine from Queen Mary University of London  looks at some of the machines contrived in earlier times  to support dreams of artificial intelligence. 

    The project acknowledges support from UKRI, Oxford's Faulty of History and Mathematical Institute, Wadham College Oxford and the HAPOC Commission. With thanks to David Dunning,  Máté  Szabó, Colin Williams and colleagues at the Bodleian Libraries, History of Science Museum,  Oxford History and Oxford Mathematics.



    Friday 9th September, 09.30-17.30, Workshop, Further details

    09.30 Register, Blackwell Hall cafe opens  

    10.00 Welcome and introduction, Professor Ursula Martin, Wadham College Oxford and Oxford Mathematics

    10.10 Professor Sharon Ruston,  ‘Minds and Machines in Mary Shelley’s Frankenstein and beyond’

    Abstract: The question of whether the Creature in Frankenstein is human is one that continues to be asked. Is he more like a man or a machine? In what ways is he like or like us? How much humanity does his maker, Victor Frankenstein, demonstrate in the novel? In this talk, I’ll consider how Mary Shelley’s novel discusses concepts such as the mind, morality, and the soul. I’ll look at other literary examples of apparently mindless states of being, such as suspended animation, somnambulism, and automata. I will also examine some unpublished manuscript notebook pages of the young Davy as he reflects on the dangerous idea that the mind might be thought of as merely a thinking machine. A page of Mary Shelley's manuscript can be seen in the accompanying display.

    Biography: Professor Ruston is Chair in Romanticism at Lancaster University. She has published The Science of Life and Death in Frankenstein (2021), Creating Romanticism (2013), Romanticism: An Introduction (2010), and Shelley and Vitality (2005). She co-edited the Collected Letters of Sir Humphry Davy for Oxford University Press (2020). She currently leads an AHRC-funded project to transcribe all of the notebooks of Sir Humphry Davy (and urges everyone to help with this task!), details are here: Davy Notebooks Project | Zooniverse - People-powered research.

    10.50 Dr David E Dunning, "A Purely Mechanical Form”: William Stanley Jevons and the Materiality of Reasoning

    Abstract: In the 1860s, philosopher of science and political economist William Stanley Jevons (1835–1882) designed a Logic Machine that, he claimed, reduced deduction “to a purely mechanical form.” As a box with a keyboard that mechanically spits out solutions to problems input by a user, this Logical Piano (as it is also known) readily evokes an embryonic idea of the digital computer when viewed with modern eyes. But perhaps what links this device most profoundly to today's computers is, ironically, the fact that it was not really about computing. While the digital computer’s better known predecessors (such as Babbage’s engines) were concerned with numerical calculation, Jevons pursued a more philosophical goal, aiming to show that reasoning was a fundamentally material process. Like the notions of AI that emerged in the second of half of the twentieth century, his project envisioned a form of computing far more expansive than number crunching. In this talk I will situate Jevons’s machine in the context of early symbolic logic that produced it, focusing on the novel techniques of writing that he built on, and built into his device. I will use this history to understand the role of material processes such as instruction, display, and memory in the context of machines and the intelligence we imagine them to possess. The machine can be seen in the accompanying display.

    Biography: David E. Dunning is a Lecturer in the Integrated Studies Program at the University of Pennsylvania and the 2022–23 IEEE Life Member History Fellow. He is a historian of science, technology, and mathematics, whose research focuses on the material and social dimensions of abstract knowledge. He co-developed the  Imagining AI display while at the Mathematical Institute at the University of Oxford. 

    11.30 David C. Brock, Learning from AI’s Eternal Recurrence: Documenting the History of Expert Systems at the Computer History Museum

    Abstract: The starting point for some of the Computer History Museum’s most recent work to document the history of artificial intelligence – through proactive collecting and oral histories – was recognizing a striking recurrence of both rhetoric and action in and around the artificial intelligence community. Increasingly over the past decade, researchers and commentators alike have hailed the combination of neural networks with large data sets and vast amounts of computing resources as a fundamental break with the past, with transformative sociopolitical implications for the near and far futures. The current CEO of Google recently went so far as to compare this to the first human control of fire. This same rhetoric – and the same flurry of action spanning commercialization and expanded government, especially military, interest and investment – can be found in the artificial intelligence community and commentators of the 1980s. Then, the past-shattering and future-altering combination was expert systems and advanced computing resources. In this talk, I will attempt to elucidate this recurrence, and will argue that one of the most celebrated achievements of the expert systems era – the military logistics system, DART, deployed by the US in the Gulf War of 1990-1991 – shows one possible future for our current moment.

    Biography: David C. Brock is the Director of Curatorial Affairs, and the Director of the Software History Center, for the Computer History Museum in Mountain View, California. He is the co-author of Moore’s Law: The Life of Gordon Moore, Silicon Valley’s Quiet Revolutionary (Basic Books, 2015) and of Makers of the Microchip: A Documentary History of Fairchild Semiconductor (MIT Press, 2010).

    12.10 Lunch can be purchased in the Blackwell Hall Cafe, or elsewhere. Cold drinks and dedicated seating available.

    13.30 Dr Troy Astarte, Christopher Strachey and the “thinking” machine 

    Abstract: As the electronic calculator of the 1940s was replaced by the computer of the 1950s, and its flexibility was slowly revealed, comparisons to human cognition were immediate: Giant Brains and Faster than Thought. While most who worked with computers knew this was little but a metaphor, the question of whether machines could really think was a good route for exploring their capabilities. This was certainly the case for Christopher Strachey (1916–1975), with a Bloomsbury Group pedigree and protean curiosity. In 1950, he was a schoolmaster at Harrow, but managed to find himself time to experiment with computers. While most computer applications were still numerical, Strachey explored games, literature, and music, alongside systems to make programming easier. These various programs, some of them almost unique in their time, gave Strachey ample opportunity to ruminate on the question of computers and their ability to think—or lack thereof. Strachey's notes can be seen in the accompanying display.

    Biography: Troy Kaighin Astarte is a teaching-focused lecturer in computer science at Swansea University. Educated in computing at Newcastle University, their research interest moved to the history of computing and computer science in particular. Building on research on the history of formal semantics of programming languages, and the history of concurrency, Troy is interested in questions about the role of computer science in shaping the world and vice-versa. 

    14.10 Dr Máté Szabó, Max Newman's Influence on Turing's Early Work

    Abstract: In 1936 Turing published his groundbreaking article “On Computable Numbers”, in which he described a mathematical model of machine computation that later became known as Turing Machines. Turing became interested in the topic while attending Max Newman’s course on logic and foundations of mathematics a year earlier. In this talk I will take a look at little known early works of Newman and show how they ifluenced Turing’s seminal paper. 

    Biography: Máté Szabó is a historian and philosopher of computing and mathematical logic. He earned his PhD in "Logic, Computation and Methodology" from the Department of Philosophy at Carnegie Mellon University. He co-developed the  Imagining AI display while at the Mathematical Institute at the University of Oxford, and is currently he is a lecturer at the University of Greenwich.

    14.50 Dr Kanta Dihal (Cambridge) author of "AI Narratives" (OUP)

    15.30 Break, cold drinks and dedicated seating available.

    16.00 Panel discussion chaired by Professor Rob Iliffe The panel will explore how the history and philosophy of AI and computing can enrich contemporary conversations about the use of these transformative technologies.  Rob Iliffe is Head of Oxford's Faculty of History.

    17.30 Wine reception.

    Abstract

    Join us in Oxford in September 2022  for displays, demonstrations and a lively workshop discussions celebrating the minds, manuscripts and machines that made the dreams and realities that  we now call artificial intelligence. 

    Mon, 19 Sep 2022 09:00 -
    Tue, 20 Sep 2022 17:00
    L2 and L5

    4th IMA Conference on The Mathematical Challenges of Big Data

    Please see the programme.
    Abstract

    4th IMA Conference on The Mathematical Challenges of Big Data


    The 4th Ima Conference on The Mathematical Challenges of Big Data is issuing a Call For Papers for both contributed talks and posters. Mathematical foundations of data science and its ongoing challenges are rapidly growing fields, encompassing areas such as: network science, machine learning, modelling, information theory, deep and reinforcement learning, applied probability and random matrix theory. Applying deeper mathematics to data is changing the way we understand the environment, health, technology, quantitative humanities, the natural sciences, and beyond ‐ with increasing roles in society and industry. This conference brings together researchers and practitioners to highlight key developments in the state‐of‐the art and find common ground where theory and practice meet, to shape future directions and maximize impact. We particularly welcome talks aimed to inform on recent developments in theory or methodology that may have applied consequences, as well as reports of diverse applications that have led to interesting successes or uncovered new challenges.

    Contributed talks and posters are welcomed from the mathematically oriented data science community. Contributions will be selected based on brief abstracts and can be based on previously unpresented results, or recent material originally presented elsewhere. We encourage contributions from both established and early career researchers. Contributions will be assigned to talks or posters based on the authors request as well as the views of the organizing committee on the suitability of the results. The conference will be held in person with the option to attend remotely where needed.

     

    Inducement of sparsity, Heather Battey
    Sparsity, the existence of many zeros or near-zeros in some domain, is widely assumed throughout the high-dimensional literature and plays at least two roles depending on context. Parameter orthogonalisation (Cox and Reid, 1987) is presented as inducement of population-level sparsity. The latter is taken as a unifying theme for the talk, in which sparsity-inducing parameterisations or data transformations are sought. Three recent examples are framed in this light: sparse parameterisations of covariance models; systematic construction of factorisable transformations for the elimination of nuisance parameters; and inference in high-dimensional regression. The solution strategy for the problem of exact or approximate sparsity inducement appears to be context specific and may entail, for instance, solving one or more partial differential equation, or specifying a parameterised path through transformation or parameterisation space.

     

    Confirmed Invited Speakers
    Dr Heather Battey, Imperial College London
    Prof. Lenka Zdebrova, EPFL (Swiss Federal Institute Technology)
    Prof. Nando de Freitas, Google Deep Mind
    Prof. Tiago de Paula Peixoto, Central European University

    Please follow the link below for Programme and Registration:

    https://ima.org.uk/17625/4th-ima-conference-on-the-mathematical-challen…

     

    Mon, 10 Oct 2022

    12:45 - 13:45
    L1

    Timelike Liouville gravity on the sphere and the disk

    Teresa Bautista
    (King's College London)
    Abstract

    Liouville conformal field theory models two-dimensional gravity with a cosmological constant and conformal matter. In its timelike regime, it reproduces the characteristic negative kinetic term of the conformal factor of the metric in the Einstein-Hilbert action, the sign which infamously makes the gravity path integral ill-defined. In this talk, I will first discuss the perturbative computation of the timelike Liouville partition function around the sphere saddle and propose an all-orders result. I will then turn to the disk and present the bulk 1-point functions of this CFT, and discuss possible interpretations in terms of boundary conditions.

    Tue, 11 Oct 2022
    12:00
    Virtual

    Evaluating germs at poles and locality

    Sylvie Paycha
    (Institute of Mathematics University of Potsdam)
    Abstract

    How to evaluate  meromorphic germs at their poles while preserving a
    locality principle reminiscent of locality in QFT is a    question that lies
    at the heart of  pQFT. It further  arises in other disguises in number

    theory, the combinatorics on cones and toric geometry. We introduce an
    abstract notion of locality and a related notion of mutually independent
    meromorphic germs. The question then amounts to  extending the ordinary
    evaluation at a point on holomorphic germs to certain algebras of
    meromorphic germs, in such a way that the extension  factorises  on mutually
    independent germs.
    In the talk, we shall describe a family of such extended evaluators on germs
    of meromorphic germs in several variables  with a prescribed type of
    (linear) poles and show that modulo a Galois type transformation, they
    amount to a minimal subtraction scheme in several variables.
    This talk is based on joint work with Li Guo and Bin Zhang.

    Tue, 11 Oct 2022

    14:30 - 15:00
    L3

    Fooled by optimality

    Nick Trefethen
    (University of Oxford)
    Abstract

    An occupational hazard of mathematicians is the investigation of objects that are "optimal" in a mathematically precise sense, yet may be far from optimal in practice. This talk will discuss an extreme example of this effect: Gauss-Hermite quadrature on the real line. For large numbers of quadrature points, Gauss-Hermite quadrature is a very poor method of integration, much less efficient than simply truncating the interval and applying Gauss-Legendre quadrature or the periodic trapezoidal rule. We will present a theorem quantifying this difference and explain where the standard notion of optimality has failed.

    Thu, 13 Oct 2022

    12:00 - 13:00
    L1

    OCIAM TBC

    Steven Strogatz
    (Cornell University)
    Further Information

    Steven is Jacob Gould Schurman Professor of Applied Mathematics. He is known for his work on nonlinear systems, including contributions to the study of synchronization in dynamical systems, and for his research in a variety of areas of applied mathematics, including mathematical biology and complex network theory.

    Thu, 13 Oct 2022

    14:00 - 15:00
    L3

    TBA

    Jerome Droniou
    (Monash University)
    Fri, 14 Oct 2022
    14:00
    L3

    Stochastic dynamics of cell fate decisions and the gene regulatory networks that underlie them

    Prof Adam MacLean
    (USC Dornsife College of Letters, Arts and Sciences University of Southern California)
    Abstract

    Cell fate decision-making is responsible for development and homeostasis, and is dysregulated in disease. Despite great promise, we are yet to harness the high-resolution cell state information that is offered by single-cell genomics data to understand cell fate decision-making as it is controlled by gene regulatory networks. We describe how we leveraged joint dynamics + genomics measurements in single cells to develop a new framework for single-cell-informed Bayesian parameter inference of Ca2+ pathway dynamics in single cells. This work reveals a mapping from transcriptional state to dynamic cell fate. But no cell is an island: cell-internal gene regulatory dynamics act in concert with external signals to control cell fate. We developed a multiscale model to study the effects of cell-cell communication on gene regulatory network dynamics controlling cell fates in hematopoiesis. Specifically, we couple cell-internal ODE models with a cell signaling model defined by a Poisson process. We discovered a profound role for cell-cell communication in controlling the fates of single cells, and show how our results resolve a controversy in the literature regarding hematopoietic stem cell differentiation. Overall, we argue for the need to consider single-cell-resolved models to understand and predict the fates of cells.

    Thu, 20 Oct 2022

    12:00 - 13:00
    L1

    OCIAM TBC

    Prof Halim Kusumaatmaja
    (Durham University)

    The join button will be published 30 minutes before the seminar starts (login required).

    Abstract

    Prof Halim Kusumaatmaja's group is interested in theoretical and computational soft matter and biophysics. Their work is interdisciplinary, lying at the interface between Physics, Chemistry, Engineering and Biology. They are also part of the Durham Centre for Soft Matter, the Biophysical Sciences Institute, and the SOFI CDT. See here for more detailed descriptions.

    Fri, 21 Oct 2022

    14:00 - 15:00
    L3

    Systematic elucidation of genetic mechanisms underlying cholesterol uptake

    Prof ~Richard Sherwood
    (Brigham and Womens Hospital Harvard Medical School)
    Abstract

    The overall goal of the Sherwood lab is to advance genomic and precision medicine applications through high-throughput, multi-disciplinary science. In this talk, I will review a suite of high-throughput genomic and cellular perturbation platforms using CRISPR-based genome editing that the lab has developed to improve our understanding of genetic disease, gene regulation, and genome editing outcomes.

    This talk will focus on recent efforts using combined analysis of rare coding variants from the UK Biobank and genome-scale CRISPR-Cas9 knockout and activation screening to improve the identification of genes, coding variants, and non-coding variants whose alteration impacts serum LDL cholesterol (LDL-C) levels. Through these efforts, we show that dysfunction of the RAB10 vesicle transport pathway leads to hypercholesterolemia in humans and mice by impairing surface LDL receptor levels. Further, we demonstrate that loss of function of OTX2 leads to robust reduction in serum LDL-C levels in mice and humans by increasing cellular LDL-C uptake. Finally, we unveil an activity-normalized base editing screening framework to better understand the impacts of coding and non-coding variation on serum LDL-C levels, altogether providing a roadmap for further efforts to dissect complex human disease genetics.

    Thu, 27 Oct 2022

    12:00 - 13:00
    L1

    OCIAM TBC

    Saverio Spagnolie
    (Univeresity of Wisconsin-Madison)

    The join button will be published 30 minutes before the seminar starts (login required).

    Further Information

    Saverio E. Spagnolie is Associate Professor of Mathematics and (by courtesy) Chemical & Biological Engineering. His research areas include Fluid Mechanics, Soft Matter, Biophysics, Applied Mathematics, Numerical Methods.

     
    Fri, 28 Oct 2022

    14:00 - 15:00
    L3

    Emergent digital biocomputation through spatial diffusion and engineered bacteria

    Prof Chris Barnes
    (Dept of Cell and Developmental Biology UCL) )
    Abstract

    Building computationally capable biological systems has long been an aim of synthetic biology. The potential utility of bio-computing devices ranges from biosafety and environmental applications to diagnosis and personalised medicine. Here we present work on the design of bacterial computers which use spatial patterning to process information. A computer is composed of a number of bacterial colonies which, inspired by patterning in embryo development, communicate using diffusible morphogen-like signals. A computation is programmed into the overall physical arrangement of the system by arranging colonies such that the resulting diffusion field encodes the desired function, and the output is represented in the spatial pattern displayed by the colonies. We first mathematically demonstrate the simple digital logic capability of single bacterial colonies and show how additional structure is required to build complex functions. Secondly, inspired by electronic design automation, an algorithm for designing optimal spatial circuits computing two-level digital logic functions is presented, extending the capability of our system to complex digital functions without significantly increasing the biological complexity. We implement experimentally a proof-of-principle system using engineered Escherichia coli interpreting diffusion fields formed from droplets of an inducer molecule. Our approach will open up new ways to perform biological computation, with applications in synthetic biology, bioengineering and biosensing. Ultimately, these computational bacterial communities will help us explore information processing in natural biological systems.

    Thu, 03 Nov 2022

    14:00 - 15:00
    L3

    TBA

    Olga Mula
    (TU Eindhoven)
    Abstract

    TBA

    Thu, 10 Nov 2022

    14:00 - 15:00
    L3

    Primal dual methods for Wasserstein gradient flows

    José Carrillo
    (University of Oxford)
    Abstract

    Combining the classical theory of optimal transport with modern operator splitting techniques, I will present a new numerical method for nonlinear, nonlocal partial differential equations, arising in models of porous media,materials science, and biological swarming. Using the JKO scheme, along with the Benamou-Brenier dynamical characterization of the Wasserstein distance, we reduce computing the solution of these evolutionary PDEs to solving a sequence of fully discrete minimization problems, with strictly convex objective function and linear constraint. We compute the minimizer of these fully discrete problems by applying a recent, provably convergent primal dual splitting scheme for three operators. By leveraging the PDE’s underlying variational structure, ourmethod overcomes traditional stability issues arising from the strong nonlinearity and degeneracy, and it is also naturally positivity preserving and entropy decreasing. Furthermore, by transforming the traditional linear equality constraint, as has appeared in previous work, into a linear inequality constraint, our method converges in fewer iterations without sacrificing any accuracy. We prove that minimizers of the fully discrete problem converge to minimizers of the continuum JKO problem as the discretization is refined, and in the process, we recover convergence results for existing numerical methods for computing Wasserstein geodesics. Simulations of nonlinear PDEs and Wasserstein geodesics in one and two dimensions that illustrate the key properties of our numerical method will be shown.

    Fri, 11 Nov 2022

    14:00 - 15:00
    L3

    Identifying cell-to-cell variability using mathematical and statistical modelling

    Dr Alex Browning
    (Dept of Mathematics, University of Oxford)
    Abstract

    Cell-to-cell variability is often a primary source of variability in experimental data. Yet, it is common for mathematical analysis of biological systems to neglect biological variability by assuming that model parameters remain fixed between measurements. In this two-part talk, I present new mathematical and statistical tools to identify cell-to-cell variability from experimental data, based on mathematical models with random parameters. First, I identify variability in the internalisation of material by cells using approximate Bayesian computation and noisy flow cytometry measurements from several million cells. Second, I develop a computationally efficient method for inference and identifiability analysis of random parameter models based on an approximate moment-matched solution constructed through a multivariate Taylor expansion. Overall, I show how analysis of random parameter models can provide more precise parameter estimates and more accurate predictions with minimal additional computational cost compared to traditional modelling approaches.

    Thu, 17 Nov 2022

    12:00 - 13:00
    L1

    OCIAM TBC

    Professor John Maddocks
    (École Polytechnique Fédérale de Lausanne (EPFL))

    The join button will be published 30 minutes before the seminar starts (login required).

    Further Information

    Born in Scotland and a former member of the British Olympic sailing team, the mathematician obtained his doctorate in Oxford. After several years as professor of mathematics in Maryland, USA, he returned to Europe to the École Polytechnique Fédérale de Lausanne (EPFL), where he has worked for nearly 20 years.

    John Maddocks is a prominent expert in the multiscale modeling of DNA, the nucleic acid-based biological molecule that carries genetic information. He is interested above all in the nanomechanical properties of DNA molecules. These properties determine how DNA is "packed" and stored in our cells.

    Text adapted from TU Berlin