The Department of Applied Mathematics is pleased to host this series of colloquium lectures, funded in part by a generous gift from the Boeing Company. This series will bring to campus prominent applied mathematicians from around the world.
The talks should be of general interest to researchers and students in the mathematical sciences and related fields. All are welcome to attend.
There will be three talks in this series each quarter, on Thursday afternoons at 4:00pm. Each talk will be followed by a reception. Please note that seminar locations for each seminar may vary. Below is a list of the Boeing seminars in the autumn, winter, and spring quarters of the 2013-2014 academic year.
Current Boeing Seminars for 2013-2014
October 17, 2013. Gowen Hall 301
Tamara Kolda, Sandia National Labs
Analytical and Algorithmic Challenges in Network Analysis
October 24, 2013. Gowen Hall 301
Bard Ermentrout, University of Pittsburgh
All the way with Gaston Floquet: A theory for flicker hallucinations
When the human visual system is subjected to diffuse flickering light in the range of 5-25 Hz, many subjects report beautiful swirling colorful geometric patterns.In the years since Jan Purkinje first described them, there have been many qualitative and quantitative analyses of the conditions in which they occur.
Here, we use a simple excitatory-inhibitory neural network to explain the dynamics of these fascinating patterns. We employ a combination of computational and mathematical methods to show why these patterns arise. We demonstrate that the geometric forms of the patterns are intimately tied to the frequency of the flickering stimulus. We combine a Turing-type stability analysis with Floquet stability theory to find parameters regimes where there are flicker-induced hallucinations. We close with some general comments on what symmetric bifurcation theory says about the patterns
December 5, 2013
Anna-Karin Tornberg, KTH-Stockholm
In micro-fluidic applications where the scales are small and viscous effects dominant, the Stokes equations are often applicable. The suspension dynamics of fluids with immersed rigid particles and fibers are very complex also in this Stokesian regime, and surface tension effects are strongly pronounced at interfaces of immiscible fluids. Simulation methods can be developed based on boundary integral equations, which leads to discretizations of the boundaries of the domain only, and hence fewer unknowns compared to a discretization of the PDE.
Two main difficulties associated with boundary integral discretizations are to construct accurate quadrature methods for singular and nearly singular integrands, as well as to accelerate the solution of the linear systems, that will have dense system matrices. If these issues are properly addressed, boundary integral based simulations can be both highly accurate and very efficient. I will present a spectrally accurate FFT based Ewald method developed for the purpose of accelerating simulations and will discuss its application to simulations of periodic suspensions of rigid particles and rigid fibers in 3D. I will also briefly discuss a method for highly accurate simulations of interacting drops in 2D.
February 27, 2014
David Donoho, Stanford University
March 6, 2014
Weinan E, Princeton University
March 13, 2014
Mary Wheeler, University of Texas, Austin
April 24, 2014
Richard Murray, Caltech
May 8, 2014
Peter Olver, University of Minnesota
June 5, 2014
William Bialek, Princeton University
Past Boeing Seminars
October 18, 2012
Gunther Uhlmann, University of Washington
Multiwave imaging and photoacoustic tomography
Abstract: Multi-wave imaging methods, also called hybrid methods, attempt to combine the high resolution of one imaging method with the high contrast capabilities of another through a physical principle. One important medical imaging application is breast cancer detection. Ultrasound provides a high (sub-millimeter) resolution, but suffers from low contrast. On the other hand, many tumors absorb much more energy of electromagnetic waves (in some specific energy bands) than healthy cells. Photoacoustic tomography (PAT) consists of sending relatively harmless optical radiation into tissues that causes heating which results in the generation of propagating ultrasound waves (the photo-acoustic effect). Such ultrasonic waves are readily measurable. The inverse problem then consists of reconstructing the optical properties of the tissue. In Thermoacoustic tomography (TAT) low frequency microwaves, with wavelengths on the order of 1m, are sent into the medium. The rationale for using the latter frequencies is that they are less absorbed than optical frequencies. Transient Elastography (TE) images the propagation of shear waves using ultrasound. We will discuss these imaging techniques with emphasis on PAT.
October 25, 2012
Ronald Coifman, Yale University
Information Integration/Organization and numerical harmonic analysis
Abstract: We provide an overview of recent developments in methodologies for empirical organization of data. We present a geometric/analytic mathematical framework for learning, which revolves around building a network or a graph whose nodes are observations. In our framework, connections between observations are constantly reconfigured in order to achieve learning for specific tasks. In particular we will provide a synthesis of a range of ideas from mathematics and machine learning, which address the transition from a local similarity model to a global configuration. This is analogous to Newtonian Calculus, which from of a local linear model of variability, calculates a global solution to a differential, or partial differential equation. We apply these fundamentals to jointly organize the rows and columns of a matrix, viewed either as the matrix of a linear operator, or as a Database. Here the rows are viewed as functions on the columns and the columns as functions of the rows, a dual geometry is built to optimize prediction and processing . We relate these methods to ideas from classical Harmonic Analysis and indicate tools to measure success of information extraction. In particular we introduce methodologies that resemble “signal processing” on data matrices, enabling functional regression, prediction, denoising, compression fast numerics, and so on. We illustrate these ideas to organize and map out in an automatic and purely data driven fashion on music databases of audio segments, text documents, psychological questionnaires, medical profiles, physical data, financial data.
November 8, 2012
Chris Bretherton, University of Washington
Clouds, Aerosols and Climate: An Applied Problem in Need of Applied Mathematicians
January 10, 2013
Percy Deift, Courant Institute of Mathematical Sciences
Toeplitz Determinants with Fisher-Hartwig Singularities
February 14, 2013
Rachel Kuske, University of British Columbia
Noise and the Piecewise World: Sliding, Grazing and Zigzags in Random Environments
Abstract: Modeling systems with discontinous dynamics has received increased attention in biological, engineering, and environmental applications. Furthermore, across nature and engineering, delay is an inherent feature in systems with feedback and control. While there have been recent advances for analyzing the complex deterministic behavior of such systems, there are many open questions around understanding and predicting noise-driven and noise-sensitive phenomena in the piecewise continuous context. Stochastic effects can often change the picture dramatically, particularly if multiple time scales are present. This talk covers new ideas for exploring the interplay of nonlinearities, delays, randomness, and piecewise smooth dynamics, and explaining the often elusive and surprising phenomena that are observed. Progress depends on the exchange of mathematical techniques and phenomenological intution from seemingly unrelated canonical models of biophysics, mechanics, and chemical dynamics. The approaches and dynamics are illustrated in the application areas of relay control, balance, and blood diseases.