The Research On Methods Of Verifying And Evaluating Performance Of Workflow Process Models Based On Petri Net

In recent years, the workflow management system has become one of the fastest developing computer application technologies. It has already been widely applied in the field of office automation, the business procedure reengineering (BPR) and other fields such as demand planning and workflow management. The key for the workflow management system's design is to model the workflow, which is to give the abstract expression of the business process at a conceptual level. Usually, the business process is described in form by formalized method. The process is composed of some well defined activities (or tasks), the link relations, and related restrain conditions and so forth.Since Petri net has strict mathematics basic and standardized semantic, it has been a great temptation to the researchers who work at modeling and analyzing workflow. Furthermore, when complicated business processes, such as erupting simultaneously and conflicts etc, have to be taken into consideration; using Petri net apparently has an advantage over the others.The main purpose of this paper is to model the workflow, including three parts: modeling, model verification and performance evaluation.In the first part, there is a narration about the realization of modeling tools for the workflow. The contents are mainly as the followings: workflow models expressed in figures; the two-direction transformation between the active pictures and Petri net flows in the workflow; the two-direction transformation between the workflow models and xml files; questions of defining the time Petri net, xml language and so forth.The second part puts forward a verification algorithm of Petri net model which can be divided into four steps: to prove strongly connected net; to calculate rank(c); to judge SMD attribute ; to look for the initial mark alive. Each step has been described and analyzed in detail.The third part suggests a group of algorithms, which keeps the time-constrain characteristic of Petri net, together with the simplified algorithm of net. By applying the transform rule continuously, the scale of net can be reduced progressively so that the workflow systematic response time can be calculated. And this provides the basis for the further analysis and reproduction of process procedure.The last chapter gives a conclusion on the overall summary to the work of this paper, and looks forward to the work in the future.