Toward Specifying Multimedia Requirements Using a New Time Petri Net Model

Abstract

In this paper, we define a model dedicated to the specification of multimedia applications called Pre-emptive Time Petri Nets with synchronizing transitions (STPTPN) as an extension of T-time Petri nets where time is associated with transitions. The model is proposed in the general purpose to model a large scale of multimedia requirements. Thus, resource requirement issues are discussed in this paper, and addressed in the model. To deal with, resources are modelled as special places using a new mechanism called “pre-emptor hyperarc” which lets a transition be “resource strongly-enabled”, “resource-violated” or “resource-violating”. Moreover, two additional mechanisms are considered: A time suspension mechanism uses inhibitor arcs associated with stopwatches and synchronization mechanisms allow the simultaneous firing of a set of transitions (called Rendezvous), according to different schemes. Compared to other existing models, our model is provided with an adapted semantic, designed to represent clearly and accurately time requirements, as well as the complex resource-pre-empting mechanisms that are observed in multimedia systems.