Modeling complex systems with VeriJ

This paper presents VeriJ, a language designed for modeling complex supervisory control problems. VeriJ is based on a subset of the Java language with some supervisory control specific constructs added; this allows to use industrial strength integrated development environments such as Eclipse to build VeriJ models and to directly use a Java debugger to execute (simulate) these models. With the aim to perform controller synthesis in a further step, VeriJ models are translated into hierarchical finite state machines (HFSM) representing the control flow graph, using modern model transformation techniques and tools. The semantics of these HFSM is then given as a pushdown system, leading to a concise and expressive representation of the underlying discrete event system. We illustrate our modeling and transformation approach with a VeriJ model of the Nim game, for which finding a winning strategy for a player can be seen as a control problem.