Hierarchical concurrent finite state machines in Ptolemy

We implement a finite state machine (FSM) domain for specifying and simulating control functionality of a system within the Ptolemy software environment. The FSM domain is successfully integrated with synchronous dataflow (SDF) and discrete event (DE) concurrency domains in Ptolemy. In this heterogeneous combination, the semantics of FSM, concurrency and hierarchy are naturally supported in a manner similar to hierarchical concurrent FSMs (HCFSMs). Unlike most formalisms that support HCFSMs, such as Statecharts and its variants, our scheme decouples the FSM from the concurrency models, enabling selection of the most appropriate concurrency model for the problem at hand.