Research On The Expended Petri Net Based Workflow Model

In the recent years, the rapid development of computer used widely in daily work always drives more and more tasks disposed by computers. At the same time, all kinds of information systems are supported these works. However, for most of these systems running independently and communicating scantly, it is very difficult to perform tasks with others systems. Workflow management system provides an automated framework for managing intra- and inter- organization business processes, as a result, it attracts much attention of researchers recently.In the practice, researchers would like a simple and intuitive way of building process definition. As an intuitive way of building model, Petri net is the one of the researchers's most like, and process modeling can use this technology too. In modeling of workflow process,we take transitions as activities,place as pre-(or -post) condition,and tokens as inst- ances.Thus,the Petri nets can be used to identity the logical workflow primitive operators, and constructors for basic structure. Therefore, the model of petri net based workflow management (WFPN) is provided. Considering some complicated workflow process existing in the real practice, Information Control Petri Net(ICPN),which expands the Petri net in accordance with the characteristic of workflow model, is developed.Using the ICPN, the workflow model,including complex stru- ctures and controlled informations from outside system, can be created quickly and reasonably.According to the correctness concept of workflow in the real world, we provide a theoretical framework to analyze the correctness of workflow model through classic Petri net analysis methods. As for WFMC, we give its formal description, and denote it with the term "soundness". According to the conditions in the soundness definition, we proved that soundness is equivalent to the liveness and boundedness of Petri net. So the correctness verification of workflow models is transformed into the verification of liveness and boundedness of base nets of workflow models, which reduces the complexity of workflow analysis.At the same time, this way can be used to analyze the correctness of ICPN model.At last, the model of ICPN based workflow management ,which expands the model of WFPN,is applied to the CyberFlow software .As a result, it is proved to have excellent efficiently, reliably and securely ability.