Lefschetz Center for Dynamical Systems Seminar
Abstract: Solutions of kinetic equations in which a collision kernel appear often converge (in large time) to some equilibrium profile (e.g. Maxwellian or Fermi-Dirac distributions of the velocity variable). On the other hand, in many situations, this equilibrium has also to be independant of the position variable (this is due to the fact that no Maxwellian solution of the equation exists, except those which do not depend on the position variable). In our talk, we propose to give some results on how to quantify the previous effects in order to get estimates on the rate of convergence of the solutions towards the global equilibrium (that is, a Maxwellian which does not depend on the position variable). Logarithmic Sobolev inequalities are the key tool in this study.
Brown University Center for Statistical Sciences Seminar
Abstract: Whereas most cells in the body carry the normal complement of 46 chromosomes, the cells within a cancerous tumor very often present highly abnormal genomic structure. Deletions, amplifications, rearrangements and mutations are common at various scales and are highly variable amongst tumors, as indicated by molecular technologies which enable ever better measurement. It is an important statistical problem to separate those abnormalities which are sporadic from those which may not be sporadic and which may have some biological significance. I will discuss a modeling strategy for genomic aberration data which allows us to infer combinations of aberrations that together increase the chance that a precancerous cell will have a descendant tumor lineage. The likelihood component involves a network of pathway structures and MCMC is used to sample from the space of these oncogenic networks. I illustrate the methodology with comparative genomic hybridizations from several recent studies.
Brown Analysis Seminar
Scientific Computing Seminar
Abstract: Electron flow in classical and quantum semiconductor and gas dynamical flows in astrophysical jets can be modeled by compressible fluid dynamics. Simulations of the nonlinear conservation laws of gas dynamics using three modern finite-difference hyperbolic methods will be presented and contrasted: the Tadmor central scheme, the WENO-LF method, and CLAWPACK (which employs a second-order Godunov method). A brief introduction to the quantum hydrodynamic model for semiconductor devices will also be given. This is joint work with Anne Gelb, Youngsoo Ha, Justin Hernandez, Christian Ringhofer, and Chi-Wang Shu.
PDE Seminar
Scientific Computing Seminar
Ben-Gurion University, Beer-Sheva, Israel | |
In order to predict and eventually prevent these failures, a
detailed description of the elastic solution in the
neighborhood of two-dimensional singular points (under
plane-strain/stress assumptions) is essential. In
three dimensional domains, edge, vertex and edge-vertex
singularities are present, and the mathematical description
of the elastic solution is more complex.
This talk will present methods for the computation of the
singular solutions in 2-D and 3-D domains by means of p-finite
element methods, and their use in formulating a failure
criterion by experimental observations for failures in
electronic devices and in ceramic materials are presented.
Department of Mathematics Colloquium
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