What is State-Transition Graph

Most discrete-event systems are subject to evolution during lifecycle. Evolution often implies the development of new features, and their integration in deployed systems. Taking evolution into account since the design phase therefore is mandatory. A common approach consists of hard-coding the foreseeable evolutions at the design level. Neglecting the obvious difficulties of this approach, we also get system’s design polluted by details not concerning functionality, which hamper analysis, reuse and maintenance. Petri Nets, as a central formalism for discrete-event systems, are not exempt from pollution when facing evolution. Embedding evolution in Petri nets requires expertise, other than early knowledge of evolution. The complexity of resulting models is likely to affect the consolidated analysis algorithms for Petri nets. We introduce Reflective Petri nets, a formalism for dynamic discrete-event systems. Based on a reflective layout, in which functional aspects are separated from evolution, this model preserves the description effectiveness and the analysis capabilities of Petri nets. Reflective Petri nets are provided with timed state-transition semantics.