Seminars and Colloquiums
for the week of November 12, 2007
Speakers:
Mr. Masato Kobayashi, Tuesday
Professor Remus Nicoara, Wednesday
Professor Cheng Wang, Thursday
Professor Petronela Radu, University of Nebraska at Lincoln, Friday
Tuesday, November 13
ALGEBRA SEMINAR
TIME: 2:10 - 3:00
ROOM: 309B Ayres
SPEAKER: Mr. Masato Kobayashi
TITLE: pullbacks and factorization properties
Wednesday, November 14
ANALYSIS SEMINAR
TIME: 3:35 - 4:25
ROOM: 209A Ayres
SPEAKER: Professor Remus Nicoara
TITLE: Commuting Squares, Hadamard Matrices and Subfactors (continued)
ABSTRACT: Commuting squares arise naturally as invariants and construction data in Jones' theory of subfactors. We investigate some existence and finiteness results for commuting squares and their associated subfactors with emphasis on those arising from complex Hadamard matrices.
Thursday, November 15
COLLOQUIUM
TIME: 3:40 - 4:25
ROOM: 214 Ayres
SPEAKER: Professor Cheng Wang (tenure/promotion candidate)
TITLE: A fourth order numerical scheme for Maxwell equations and its applications
ABSTRACT: A fourth order difference scheme of Maxwell equations over a staggered Yee grid is proposed and analyzed. A "symmetric image" extrapolation formula is utilized to avoid the difficulty around the boundary, and the Jameson Runge-Kutta method is chosen as the time integration. The full fourth order convergence analysis is provided in both L2 and L^.
infinity norms, with a derived stability condition. Numerical simulations of a benchmark cavity, single and double ridge cavities are presented. Some applications, such as the numerical simulation of a twisted wave guide and radio frequency resonant structure analysis, are also discussed in detail.
Friday, November 16
DE/APPLIED AND COMPUTATIONAL MATH SEMINAR
TIME: 3:35 - 4:30
ROOM: 309A Ayres
SPEAKER: Professor Petronela Radu, University of Nebraska at Lincoln
TITLE: Decay rates for wave equations with variable coefficients and linear damping
ABSTRACT: In this talk we will discuss decay rates for a PDE which models traveling waves in a non-homogeneous gas with damping that changes with the position. This problem has been studied intensively for the homogeneous medium, but the results are scarce for the variable coefficient case. In fact, to the authors' knowledge, the results of this paper are the first to be obtained for wave equations with variable coefficients on the entire space when damping is present. The proof is based on the multiplier method where the multiplier is cleverly engineered from an asymptotic profile of solutions. These results were obtained in collaboration with G. Todorova and B. Yordanov.
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Seminars from 2006-2007 academic year