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Stochastic Systems Seminar
(Joint Work with Ad Ridder) | |
Abstract: We analyse the deviant behavior of a queue fed by a large number $n$ of traffic streams, where buffer and link speed are scaled by $n$. In particular, we explicitly give the most likely trajectory (or `optimal path') to buffer overflow, by applying large deviations techniques. Here we rely on both the pathwise approach of Weiss, and the somewhat more direct approach of Botvich and Duffield. This is done for a broad class of sources, consisting of Markov fluid sources and periodic sources. Apart from a number of ramifications of this result, we present guidelines for the numerical evaluation of the optimal path.
Brown Applied Mathematics Pattern Theory and Vision Seminar
Abstract:
I will present a new segmentation algorithm, based on a family of ordinary
differential equations called "stabilized inverse diffusion equations"
("SIDEs"). It will be shown both that SIDEs have some important mathematical
properties and that they hold considerable promise for edge enhancement and
segmentation, especially in the presence of noise. In particular, they can
produce sharp enhancement of edges in high noise as well as accurate
segmentations of very noisy images such as synthetic aperture radar (SAR)
and ultrasound images subject to severe speckle.
I will describe the relations of SIDEs to several existing algorithms
for image restoration and segmentation, such as anisotropic diffusions, shock
filters, and region merging methods. A closer analysis of SIDEs in 1-D
reveals that they provide maximum likelihood solutions for certain edge
detection problems. This fact means that classical change detection results
can be used for performance analysis in some special cases. The robustness of
the algorithm can also be analyzed using an H-infinity-like criterion. I will
also sketch a fast implementation of the algorithm.
Brown Analysis Seminar
Workshop on Fronts, Patterns and Pulses in Reacting Systems
11:00 - Robert A. Gardner, University of Massachusetts, 1:30 - Benjamin B. Kimia, Brown University, 3:00 - Yasumasa Nishiura, Hokkaido University | |
11:00 - Stability Analysis of Periodic Waves 1:30 - Exact Wave Propagation on a Discrete Grid 3:00 - Self-Replication and Self-Destruction in Reaction Diffusion Systems - (This talk will be held jointly with PDE seminar.) | |
Morning session will be held at 37 Manning St. Room 104 Afternoon session will be held at 182 George St. Room 110 |
Scientific Computing Seminar
Abstract: Computational Aeroacoustics (CAA) treats time dependent problems involving large bandwidth in frequency and wavenumber. Because the nature of acoustics is quite different from that of conventional fluid dynamics, special computational requirements must be addressed. To meet these requirements, new computational methods and boundary conditions have been developed. In this talk, these requirements and methods will be reviewed. Applications of the new methods and boundary conditions to the solution of airframe and jet noise problems will be presented.
Joint PDE & LCDS Seminar
Department of Mathematics Colloquium
<--- 1999 Index