C-PLAD-SM: Extending component requirements with use cases and state machines

Classic approaches to component specification derived from component requirements emphasize identifying external interfaces and behaviors. The C-PLAD requirements model provided a unifying framework for combining domain requirements and application requirements through an iterative refinement process. C-PLAD repackaged UML features and Unified Process techniques into an iterative process. In our continuing work, we found another layer was required-the inclusion of state machines to drive the architectural specifications beyond component interfaces and into component states in order to provide guarantees in our domains of interest, namely safety-critical applications. In this paper we describe an extension to the C-PLAD approach, dubbed C-PLAD-SM, which addresses the gaps in our earlier work.