Prioritized Synchronization under Mask for Interaction/Control of Event-Driven Systems

The paper introduces a formalism for modeling interaction and control of partially observed discrete event systems, called prioritized synchronous composition under mask (PSC/M). PSC/M is able to capture several common modes of interactions such as strict/prioritized synchronization, interleaving, hiding and renaming. As a result PSC/M can serve as a single canonical model of interaction. PSC/M possesses the useful properties of commutativity and associativity. When PSC/M is employed as a control mechanism, it helps remove the control and the observation compatibility requirements of the control. We study the PSC/M-based control problem where both plant and supervisor have their own control and observation limitations. The existence condition is achievability, which is weaker than controllability and observability combined. (A weaker condition is required since we allow supervisors to be nondeterministic.) Both the existence and synthesis can be performed polynomially in the size of the plant and the specification. We show that in the setting of PSC/M the problem of control for a partial specification (one defined over a subset of events) can be transformed to the one of control for complete specification