Integrated Architectural Modeling of Real-Time Concurrent Systems with Applications in FMS 1

 A Real-time Architectural Specification (RAS) model and its application in the modeling of flexible manufacturing system (FMS) are presented. An FMS is a typical real-time concurrent system compos ed of a number of computer-controlled machine tools, automated material handling and storage systems tha t operate as an integrated system under the control o f host computer(s). The growing demand for higher performa nce and flexibility in these systems and the interlocki ng factors of concurrency, deadline-driven activities, and rea l-time decision making pose a significant challenge in FMS design, especially in terms of control and scheduli ng. A formal engineering approach that helps handle the complexity and dynamics of FMS modeling, design and analysis is needed. RAS combines mature operational and descriptive formal methods, in particular Time Petr i nets (TPN) and Real-Time Computational Tree Logic (RTCTL), to form an integrated system model for architectural specification and analysis of real-ti me concurrent systems such as FMS. The contribution of RAS is twofold: First, it provides a formal system to systematically maintain a strong correlation betwee n (r altime) requirements and design and to verify the conformance of the design to the requirements, whic h helps enhance traceability and thus to help us to a chieve high assurance in design. Second, it offers better scalability in modeling and analysis, which provide s an effectively way to deal with complexity in the appl ication of formal methods. These two features together make RAS a suitable model for the design of FMS.