Process objects/masked composition: an object-oriented approach for modeling and control of discrete-event systems

An object-oriented framework for modeling and supervisory control of discrete event systems is described. Control and observation masks are encapsulated with process logic to form process objects, and a single type of interconnection operator called masked composition is used to build complex process objects out of simpler component process objects. The approach applies to both deterministic and nondeterministic plant models and supervisory design. In addition to the usual benefits of object-oriented design, such as software reusability, it yields conditions under which the existence of a nondeterministic supervisor implies existence of a deterministic supervisor.