| Date: September 29 |
| Speaker: Kevin Drummey, NSA |
| Title: NSA Summer Program Opportunity |
| Abstract:In this seminar, we provide an overview of NSA and its Summer Program for Operations Research Technology (SPORT), which is a 12-week internship for graduate students enrolled in an M.S. or Ph.D. program who also have experience in computer programming. The goal of SPORT is to offer top graduate students, who have highly developed operations research and applied math skills, a unique opportunity to apply their knowledge to actual problems that are encountered at NSA in one of the most advanced intelligence gathering environments in the world. Specific areas of technical interest include: Operations Research, Modeling and Simulation, Industrial/Systems Engineering, Probability and Statistics, and Management Science.
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| More Information: Talk begins at 4:30 p.m. in room 101, Sherrerd Hall |
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| Date: October 5 |
| Speaker: Robert Eisenberg, Rush Medical Center/Chicago and Argonne National Labs |
| Title: Self-organized selectivity in Calcium and Sodium Channels: important biology ready for mathematical analysis |
| Abstract: Ion channels are irresistible objects for biological study because they are the [nano] ‘valves of life’ controlling an enormous range of biological function, much as transistors control computers. Ion channels are appealing objects for physical investigation because conformation changes are not involved in channel function, once the channel is open. Open channels are interesting objects for chemical study because they effectively select among chemically similar ions, under unfavorable circumstances. Channels are interesting objects for physical study because they contain an enormous density of charge, fixed, mobile, and induced. Direct simulation of channel behavior in atomic detail is difficult if not impossible, because ion transit takes ~ 10-8 sec compared to a simulation calculation time step of 10-16 sec and a biological time scale beginning at 10-4 sec. Direct simulation must deal with concentrations of 10-7 to 55 M in a single calculation, and macroscopic electric fields and concentration gradients produce substantial flows which are the function of the channel, making equilibrium analysis unhelpful.
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| Date: October 12 |
| Speaker: Raphy Coifman, Yale University (joint w/analysis seminar) |
| Title: Harmonic Analysis and Geometries of Digital Data Bases |
Abstract: Given a matrix (of Data) we describe methodologies to build two multiscale (inference) Geometries/Harmonic Analysis one on the rows , the other on the columns . The geometries are designed to simplify the representation of the data base . We will provide a number of examples including; matrices of operators , psychological questionnaires, vector valued images, scientific articles, etc.
In all these cases tensor Haar orthogonal bases play a crucial role in organizing the data base viewed as a function of two variables (row,
column) in the case of potential operators we relate to Calderon Zugmund decompositions , while for other data this is a "data agnostic analytic learning tool"
For the example of the matrix of eigenfunctions of a discretized Laplace operator ( say, on a compact manifold) we obtain both the Geometry of the domain of the Laplace operator as well as a dual multiscale Geometry of the eigenvectors. |
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| Date: October 26 |
| Speaker: Howard Stone, Mechanical and Aerospace Engineering |
| Title: Some variants on the flows of suspensions: Diffusion, dispersion, and biofilms |
| Abstract: In this talk I will present several fluid mechanics problems that concern the flow of particles and suspensions. This topic has many variants, which I will introduce to provide breadth and perspective for the listener (most of you) who has not studied the topic. After the introduction I will highlight (i) shear-enhanced diffusion, as studied in a microfluidic device, (ii) axial dispersion due to shear-enhanced diffusion, and (iii) unusual structures formed when bacteria flow, and biofilms grow, in curved channels. Some answers will be given and open questions will be indicated. |
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| Date: November 9 |
| Speaker: Mauro Maggioni, Duke University |
| Title: Geometry and Analysis of point sets in high dimensions |
| Abstract: The analysis of high dimensional data sets is useful in a large variety of applications, from machine learning to dynamical systems: data sets are often modeled as low-dimensional, noisy data sets embedded in high-dimensional spaces; dynamical systems often have very high-dimensional state spaces but sometimes interesting dynamics occurs on low-dimensional sets. We discuss several problems associated with the analysis of the geometry of such sets, and with the approximation of functions on such sets, together with some solutions: in particular we discuss how to construct random walks on such data sets and perform multiscale analysis of them and their applications (especially to machine learning); how to construct robust coordinate systems for data sets; how to estimate reliably the intrinsic dimensionality of the data when only few noisy samples are available. |
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| Date: November 16 |
| Speaker: Erik Vanmarcke, Civil and Environmental Engineering |
| Title: Testable New Theory about Early-Universe Density Fluctuations and Origins of Solar Systems: Applied-Probability and Quantum-Physics Aspects |
| Abstract: The talk will summarize, with a focus on applied-probability aspects, the main findings, testable predictions and research opportunities stemming from a new probabilistic model of how complex patterns of energy-density fluctuations may have arisen during the inflation phase of the Big Bang. Based on first (quantum-physical) principles and requiring a minimum number of (observationally-accessible) parameters, the "embryonic inflation model" yields a coherent set of testable (hence falsifiable) hypotheses about the formation, evolution, composition, internal structure and cosmic environment of galaxies, stars and planets, and is consistent with key findings from observations of the Cosmic Microwave Background (CMB). Implying a robust alternative (and challenge) to the dual paradigm of spatially-uniform light-element primordial nucleosynthesis and stellar "recycling" of matter as the sole mechanism of heavy-element production, the theory holds the promise of integrating astrophysical and planetary sciences with cosmology and galaxy formation in a coherent evolutionary framework. Observations indicating overall cosmic flatness, the existence of an accelerating component, dark matter and dark energy all fit, in quantifiable and testable ways, into the framework of the theory. |
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| Date: November 23 |
| Speaker: Warren Powell, ORFE |
| Title: Solving High-Dimensional Stochastic Optimization Problems using Approximate Dynamic Programming |
| Abstract: There are many stochastic resource allocation problems arising in transportation, energy and
health that involve high-dimensional state and action variables in the presence of di erent forms of
uncertainty. These might involve discrete or continuous resources, and generally involve vectors of
random variables that preclude exact computation of expectations. I will also describe our research into the important \exploration vs. exploitation" problem that
arises in approximate dynamic programming, where we have the ability to choose the next state we
will visit. |
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| Date: November 30 |
| Speaker: Joris Dik, Delft University of Technology, Netherlands |
| Title: Looking over the painter’s shoulder |
| Abstract: Just microns below their paint surface lies a wealth of information on Old Master Paintings. Hidden layers can include the underdrawing, the underpainting or compositional alterations by the artist. All too often artists simply re-used their canvases and painted a new composition on top. Thus, a look /through /the paint layer provides a look /over/ the painter’s shoulder. I will discuss case different subsurface imaging techniques and present case studies from the work of Vincent van Gogh and Rembrandt. |
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| Date: December 7 |
| Speaker: Roy S. Berns, Munsell Color Science Laboratory, Chester F. Carlson Center for Imaging Science, Rochester Institute of Technology, USA
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| Title: Imaging Techniques and the Rejuvenation of Artwork |
| Abstract: Advances in digital imaging within the visible spectrum enable the accurate color rendering of artwork. It is possible to generate a colorimetric image with high spatial resolution and high image quality (appropriate sharpness and low noise). When the number of sensor channels exceeds three, it is also possible to generate spectral images. Spectral images can be used to calculate colorimetric images for any illuminant and observer pair, to evaluate color inconstancy, as an aid in retouching (i.e., “restorative inpainting”), for pigment mapping, and to improve printed reproductions. These digital images, of course, record the color and spectra of the artwork in its current condition. Depending on how the artwork has aged, its color may bear little resemblance to its appearance when first executed. This can dramatically affect the analysis of the painting in terms of its historical context and understanding the artist’s working methods. A variety of techniques can be used to determine such color changes including analysing cross-sections, finding protected areas and identical materials that retain their color, early photographic records, and descriptions by art critics and connoisseurs at the time of creation. Having determined that a color change has occurred, it is possible to “rejuvenate” the colors of a digital image by using the principles of instrumental-based color matching. These principles are used to determine pigments and their concentrations that when mixed, match a particular color. This is equivalent to pigment mapping. The digital rejuvenation is performed by either replacing the spectral properties of the changed pigment with one that hasn’t changed or increasing the concentration of a pigment that has faded. These rejuvenated images, while speculative, provide important and interesting new insights. This presentation will review research by the author in digital rejuvenation using examples by Vincent Van Gogh and Georges Seurat. |
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