The Control of Discrete Event Systems

A Discrete Event System (DBS) is a dynamic system that evolves in accordance with the abrupt occurrence, at possibly unknown irregular intervals, of physical events. Such systems arise in a variety of contexts ranging from computer operating systems to the control of complex multimode processes. We survey a control theory for the logical aspects of such DESs. This theory was initiated by Ramadge and Wonham, and has subsequently been extended by the authors and other researchers to encompass control theoretic ideas such as controllability, observability, aggregation, and modular, decentralized, and hierarchical control. We concentrate on the qualitative aspects of control but also consider computation and the related issue of computational complexity.