Extending the object-process methodology to handle real-time systems

There is a general consensus in software literature that real-time systems are difficult to model, specify, and design. It is an important and challenging task to develop an intuitive and easy-to-use, yet coherent and concise method for specifying such systems. The Object-Process Methodology (OPM) graphically specifies systems in a single unified model that describes the static-structural and behavioral-procedural aspects of a system by a set of Object-Process Diagrams. In this article we present OPM/T, as an extension of OPM for specification of reactive and real-time systems. A detailed telephone-call example demonstrates the power of OPM/T to express such notions as timing constraints, events, conditions, exceptions, and control flow constructs.