Using extended fuzzy-timing Petri nets to model role-based and agent oriented collaborative virtual environment

Modeling collaborative virtual environment (CVE) is the basis of describing and solving related problems such as concurrency and consistency. In this paper, a new model adopting role theory for CVE is presented. This role-based model called RACVE defines CVE as a seven-tuple which contains all important components and describes static relations between basic collaborative entities and collaborative events. Especially, two important concepts, intelligent entity in running state and collaborative federation, are proposed to take time factor into consideration. Although the definition and static relation description are complete in RACVE model, it is still deficient in describing time-based dynamic state transition of system. The RACVE model represents only a traditional 3D system; actually, CVE is a kind of 4D system with time as its fourth dimension. In order to represent time factor explicitly and describe dynamic state of system, a Fuzzy-Timing Petri Nets formal modeling technique is employed to revise RACVE model to satisfy 4D and real-time requirement of CVE. Furthermore, state transitions for shared object, intelligent entity in running state, collaborative federation, and collaborative activity are modeled efficiently, and reinforce RACVE greatly.