Real-Time Statechart Semantics

Abstract Modelling complex dynamic real-time behavior is a crucial prerequisite when employing object-oriented modelling techniques successfully in the field of complex real-time systems. In this report we therefore review the state of the art of two related lines of research, namely extensions for expressiveness such as Statecharts as proposed in the field of software engineering to support the description of complex behavior and extensions to specify the explicit temporal behavior for state-based behavior such as Timed Automata. We review the Hierarchical Timed Automata model which provides already the most fundamental concepts for structure and time as well as a reasonable semantics for the domain of temporal behavior. To enable the modeling of complex control behavior which incorporates most of the fundamental extensions for expressiveness and time in a manner appropriate for real-time systems, we then propose an extension in form of Extended Hierarchical Timed Automata and Real-Time Statecharts. Different restricted forms reflecting the different requirements of system elements such as physical entities, communication channel abstractions and controllers running on particular platforms are further identified