Speaker: Mugizi Robert Rwebangira
Time: Wednesday 12-1pm
Place: NSH 1507
Title: A Random-Surfer Web-Graph Model
Abstract:
In this work we provide theoretical and experimental results on a random-surfer model for construction of a random graph. In this model, a new node connects to the existing graph by choosing a start node uniformly at random and then performing a short random walk. We show that in certain formulations, this results in the same distribution as the preferential-attachment random-graph model, and in others we give a direct analysis of power-law distribution of degrees or “virtual degrees” of the resulting graphs. We also present experimental results for a number of settings of parameters that we are not able to analyze mathematically.
Speaker: Robert Weisnamtel, University of Magdeburg
Date: Friday, March 31, 2006
Time: 1:30 to 3:00 pm
Place: 388 Posner Hall
Title: A Mixed Integer Linear Programming Approach for the Optimal Synthesis of Chemical Processes
Abstract:
This research is motivated by feasibility questions arising in two different areas of chemical engineering: reactive distillation processes and chromatographic processes. In both situations, there is a need to compute global bounds on the optimal value of a general polynomial mixed integer programming problem. We present our approach to tackle this question. It is based on polyhedral insights on the underlying nonlinear models and makes use of combinatorial substructures that are inherent in optimization problems of this kind.
