In: Lecture Notes in Computer Science, Vol. 1091; Proc. 17th International Conference in Application and Theory of Petri Nets (ICATPN'96), Osaka, Japan, pages 307-326. Springer-Verlag, June 1996.
Abstract: This paper describes the hierarchical, graphical SEA Language. The SEA Language relies on extended Predicate Transition Nets that unambiguously define the semantics of graphical system specifications. These nets are also used as a basis for simulating/animating system specifications. The SEA Language allows to easily incorporate several user defined or standardized graphical symbols and their behavior. Via this approach a unified semantic basis for different graphical specification formalisms/techniques can be provided. These techniques may be application independent like data flow graphs, statecharts or block diagrams for differential equations or application dependent like logical gates for hardware systems. Hence, engineers can specify system (parts) using the graphical symbols they are used to. Due to the underlying common semantics defined by extended Predicate Transition Nets, a heterogeneous system can be specified and simulated as a whole at very early stages of design before some system components are already constructed. This approach and its benefits will be explained using the well known elevator system as an example of a heterogenous system.