Study Of Distributed Cooperative Workflow Based On Time Petri Net

Distributed cooperative work environment is a kind of computer system, which allows the group numbers to share and exchange information, embodies distributed, interactive, concurrent cooperative thoughts of system engineering, and completes a task through cooperation. Regional distribution, synchronous cooperation and flow rationality reflect the feature of geographical space, time space and behavioral space respectively during operation process of distributed cooperative work environment.Workflow management technology invokes every element in the corresponding information resource and human resource, makes it execute according to some order, and then realizes operation process automation and management, accomplishes the object of operation process.Petri net, as an important tool used to modeling and analysis of concurrent system, has stronger simulation capability to the system and gives a graphical representation to the model. And it can represent concurrence, sequence, conflict, synchrony, share of system in intuitive way. The modeling method based on Petri net have enough flexibility and reliability, can resolve the problem of complex and dynamic workflow modeling effectively, and establishes stable fundament for the development of distributed cooperative workflow. Time Petri net is a modeling tool suitable to describe the real time system, and put time factor into net, which brings much convenience in the simulation and analysis of actual system.Because time Petri net can not resolve some problems, such as multi-granularity and multi-time zone time constrains, the limitation of the Petri net workflow model is analyzed. A new workflow model representation based on time Petri net is presented in this paper, which is extended time Petri net workflow (XTPN-WF). Many time Petri net workflow is merged into XTPN-WF to describe time constrains by construction rules; XTPN-WF can describe flow distributed in different time zones by inducting time mapping function related to time zone. Finally, an instance is provided using XTPN-WF to depict operation process in distributed enterprise, which describes the operation process with multi-granularity, time constrains of different time zones, synchronous cooperativeness and resource competition.