Modeling with enhanced prioritized Petri nets: EP-nets

Recently, many researchers have their attention focused on interactive temporal models, like the extended finite state machines or the extended Petri net models. One of the recent mechanisms proposed for synchronization is known as the Prioritized Petri net, P-Net, which is implemented in the Distributed Object Composition Petri Net, DOCPN. The development of DOCPN has achieved media synchronization in distributed multimedia environments. This P-Net mechanism holds a powerful property: if the deadline is due, it forces firing events regardless whether they are ready or not. A side effect might occur, which is known as premature/late arriving tokens. This paper addresses the key issue of providing flexible multimedia presentation with user interaction and suggests improved P-Net models, which handles premature/late arriving tokens, accommodates dynamic event mechanisms and can specify user interactions in real time during presentation. To demonstrate the concepts are feasible, a prototype with runtime support has been developed and used to construct several interactive multimedia applications, including skip, freeze and restart, reverse, speed scaling, and multicasting.