Simulation and Animation of Visual Models of Embedded Systems A Graph-Transformation-Based Approach Applied to Petri Nets

Behavior specification techniques like Petri nets provide a visual description of software and embedded systems as basis for behavior validation by simulation. Graph transformation systems can be used as a unifying formal approach to define various visual behavior modeling languages including different kinds of Petri nets, activity diagrams, Statecharts etc., and to provide models with an operational semantics defining simulations of visual models based on graph transformation rules. Moreover, simulation of visual models can be extended by animation which allows to visualize the states of a model simulation run in a domain-specific layout which is closer to the problem domain than the layout of the abstract diagrammatic notation of the specification technique. This kind of model transformation is defined also within the framework of graph transformation, which allows to show interesting properties like semantical correctness of the animation with respect to simulation. In this paper we give an overview of simulation and animation of visual models based on graph transformation and discuss corresponding correctness issues. As running example we use a high-level Petri net modeling the basic behavior of an elevator. We show how Petri nets are mapped to graph transformation systems, and how the elevator system is extended using an animation view which shows the movements of an elevator cabin between different floors.