« Yari Yari and The World of Romare Bearden | Main
1. Duben 2005
Bay Saint Louis - June 1983
June 1983
United States Geological Survey (USGS)
Bay St. Louis, Mississippi
TALK:
A mathematical analysis of the properties of the weighted four-point, implicit, finite-difference approximation of the Saint Venant equations. Talked about theory of oscillation matrices.
I was invited by Lewis L. DeLong whom I met two months earlier at downtown Washington, D.C. meeting between researchers of the United States Geological Survey and the United States National Weather Service.
I spent three days exchanging ideas (with Lew, David B. Thompson and mathematician Jonathan K. Lee)on the four point implicit methods for simulating river flood waves that occurs from dambreaks and flooding. We talked about stage-discharge relations, ongoing flood forecasting research at the United States National Weather Service, representations of irregular channel cross sections and the sparsity of the coefficient matrix, the works of Michael Abbott in the Netherlands and Jean Cunge & Preissman at SOGREAH-France.
DEFINITION
A matrix A is called an oscillation matrix if A is totally nonnegative and there exists a positive integer k [kappa] such that A^k [A to power kappa] is totally positive.
Harvey S. Price, Richard S. Varga, and Joseph E. Warren, Application of oscillation matrices to diffusion-convection equations, J. Math. and Phys. 45 (1966)
Posted by emeagwali at 1. Duben 2005 8:18