A unified high-level Petri net formalism for time-critical systems

The authors introduce a high-level Petri net formalism-environment/relationship (ER) nets-which can be used to specify control, function, and timing issues. In particular, they discuss how time can be modeled via ER nets by providing a suitable axiomatization. They use ER nets to define a time notation that is shown to generalize most time Petri-net-based formalisms which appeared in the literature. They discuss how ER nets can be used in a specification support environment for a time-critical system and, in particular, the kind of analysis supported