|Researchers:||Bilung Lee, Xiaojun Liu|
|Advisor:||Edward A. Lee|
Hierarchical concurrent FSMs (HCFSMs) increase the usefulness of FSMs by extending them with structuring and communication mechanisms. However, most formalisms that support HCFSMs, such as Statecharts and its variants, tightly integrate the concurrency semantics with the FSM semantics. In our approach , we add hierarchy and heterogeneity to the FSM model. This allows the FSM to be hierarchically combined with various concurrency models, in particular dataflow, discrete events and synchronous/reactive models. In this heterogeneous model, the semantics of FSM, concurrency and hierarchy are naturally supported. Our scheme decouples the FSM from the concurrency models, enabling selection of the most appropriate concurrency model for the problem at hand.
An FSM domain has been developed in Ptolemy Classic and is integrated with existing DE, SDF, and SR domains. We are currently implementing the FSM domain in Ptolemy II  with a focus on combining the CT and FSM domains for hybrid system modeling and integrating the FSM domain with process domains such as CSP and PN.
Last updated 11/05/99