A Mixed Semantics Model for Schedulability Analysis of Time Petri Nets

Two semantics, a strong semantics and a weak one, are usually adopted by time Petri nets in different application context. However, both of them are not suitable for the schedulability analysis of real-time systems. The scheduling ability of the strong semantics model is limited because of the constraints of the strong timing, whereas the weak one can not guarantee the timeliness of schedules due to the non-compulsory nature of weak timing. In this paper, we propose a mixed semantics model for time Petri nets that efficiently addresses the problem. In our models, the firability of a transition is not dependent on its conflicting transitions, but on its non-conflicting ones. This not only extends the schedule scope of the model, but also keeps some certain strong timing on choices. Therefore, the mixed semantics model can provide a good support for the schedulability analysis and timing verification of time-critical systems.