Architectural Specifications for Reactive Systems

This paper concerns the problem of building reactive systems in a modular way. Several institutions have been proposed for the specification of reactive systems throughout the last fifteen years. Based on the institutions, formalisms for the incremental construction of system specifications have been developed. Related problem of modular construction of system implementations has received less attention. This paper is the first attempt to use architectural specifications of Casl for that purpose. The semantics of the architectural specifications is based on the underlying institution. We argue that none of the institutions defined so far for reactive systems is appropriate as a basis for architectural specifications, and therefore we propose another one, better suited for this task. We also show how to express synchronisation of reactive systems using implementation-building operations of Casl architectural specifications.