查看文章

Petri nets are a kind of general formalism used for the specification and analysis of concurrent systems. Two types of Petri network extensions are relevant in the specification and analysis of time-critical systems: those that add time modeling capabilities and those that add functional modeling capabilities. A new class of Petri nets, environment/relationship (ER) nets, is introduced and demonstrated as a powerful and flexible specification formalism to support the modeling of time-critical systems. By using this formalism to unify time and the functional aspects in a semantically coherent manner, ER nets are useful as a kernel notation for defining an environment that supports the specification and analysis of time-critical systems. Many important situations that cannot be represented with previous models, such as functional aspects, are modeled by ER nets in a natural way.