9315344 Lin Discrete event systems (DES) are used to model man-made systems that are not readily described by the differential or difference equations used in traditional control theory, but rather by interactions of events that record significant qualitative changes in the systems. Several approaches to modeling, control, and optimization of DES have been proposed, each addressing a specific issue and providing an important piece of the entire puzzle of DES. However, these pieces are as yet separate and disconnected to a large extent. Furthermore, some approaches suffer from exponential computational complexities. To overcome these obstacles, the aim of this proposal is to develop a comprehensive theory of DES. In this theory, efficient implementation of on-line control will be provided; component failures will be diagnosed; hard time constraints will be satisfied; temporal performance will e evaluated; and hybrid systems will be considered. If successful, this comprehensive theory will bridge the gap between two major approaches in DES: qualitative approach addressing the logic issues and quantitative approach addressing performance issues. It will also connect research results in discrete event systems with those in continuous variable systems. It will further provide computationally efficient ways to implement control. All these will greatly enhance the applicability of DES methodologies. ***
