Mathematics Colloquum


Thursday, September 28, 1995, 4:00pm

102 Bradley Hall

Professor Rolf H. Mohring

TU, Berlin (visiting Dartmouth for the Fall term)

speaks on

Using network flows for mesh generation

Abstract. Network flow techniques are applied to a problem arising in the computer aided design of cars, planes, ships or components of them: Refine a coarse mesh of spheric polygons that approximates the surface of a workpiece such that the resulting mesh is suitable for a numerical analysis (in particular, we are asked to achieve a specified mesh density and to generate meshes consisting of quadrilaterals only).

This turns out to be a difficult discrete problem (strongly NP-hard). We show how to formulate it in terms of network flow theory. We obtain a bidirected flow problem on an undirected graph G with upper and lower capacities on the edges and some additional node balance conditions. The problem is then reduced to finding a feasible flow in that graph that satisfies all these constraints. In our talk, we introduce a generic algorithm and discuss the encouraging results of a first implementation.

The talk should be accessible to both graduate students and undergraduates; I will provide necessary background information.

This is joint work with Matthias Muller-Hannemann (Berlin) and Karsten Weihe (Konstanz).

Tea. High tea will be served at 3:30pm in the Lounge.
Emmy's. Certain refreshments will be available at the Emmy's after the talk.