Upcoming Seminars

WEDNESDAY, September 12, 2007

        ANALYSIS/PDE SEMINAR                         PSA 306   1:40 p.m.
        Fernando Carreon, Department of Mathematics and Statistics
          "A Geometrical Method to Study Front Propagation Problems"
        ABSTRACT: A geometrical approach to analyze the asymptotic
        behavior of scaled reaction diffusion equations is discussed.
        A typical example of such equations are the scaled RDE of Allen-
        Cahn type, where a front moving by its mean curvature is
        generated as the scale parameter goes to zero.
          A weak formulation of motion of hypersurfaces with curvature
        dependent velocities is presented. This notion turns out to be
        equivalent to the level set formulation under the no fattening
        condition of the fronts.

        COMPRESSIVE SENSING SEMINAR                  ECA 225   4:00 p.m.
          (In cooperation with Department of Electrical Engineering)
        Video Lecture by Emmanuel J. Candes,
                         California Institute of Technology
          "Compressive Sampling: Sparsity and Incoherence"
        ABSTRACT: Compressed sensing essentially relies on two tenets:
        the first is that the object we wish to recover is compressible
        in the sense that it has a sparse expansion in a set of basis
        functions; the second is that the measurements we make (the
        sensing waveforms) must be incoherent with these basis
        functions. This video lecture introduces key results in the
        field such as a new kind of sampling theorem which states that
        one can sample a spectrally sparse signal at a rate close to
        the information rate - and this without information loss.

FRIDAY, September 14, 2007

        C*-ALGEBRA SEMINAR                           PSA 307   9:40 a.m.
        Jack Spielberg, Department of Mathematics and Statistics
          "Intro to Graph Algebras and their K-Theory, Part 3"

        MATH BIOLOGY SEMINAR                         PSA 102   3:40 p.m.
        Nicolas Lanchier, Department of Mathematics and Statistics
          "Survival (and Coexistence) in Spatially Explicit
           Metapopulations"
        ABSTRACT: Interacting particle systems are usually defined as
        Markov processes on a state space that maps the regular lattice
        into a finite set of colors, and whose dynamics are described
        by local interactions. We extend this framework by replacing
        the usual lattice with a connected graph whose topology
        dictates how particles interact. This approach allows us to
        define a version of the contact process including two levels
        of interactions, ideally suited to model metapopulations. The
        mathematical analysis of our "two-scale" contact process
        reveals that a single species may survive if it is either a
        good competitor or a good colonizer. This also suggests that
        two species may coexist in the presence of two levels of
        interactions, which is not the case on the regular lattice.
        This is a joint work with Belhadji.