Workflow Modelling And Verification

Workflow technique has been used in corporations to improve operational efficiency, and petri net and xml techniques are broadly used in workflow modelling,workflow verification and performance evaluation.For workflow verification is so important for workflow management systems, it has been researched more and more by researchers and some methods has been proposed to detect process anomalies in workflow models. After reviewing related research papers, a method using dynamic colored graph is proposed. It describes the state of the workflow with colors. The state of the workflow changes along with the checking of the nodes. We also give four functions and four patterns according which the node is checked. The nodes of the workflow are checked one by one until an anomaly is met or no node is left. This method can verify complex workflow models including cyclic models and workflow models contain overlapping structures. All typical structure conflicts including deadlock,multiple instances and infinite cycle can be detected by this method with acceptable complexity.A simulation tool called XPNTool has been designed and implemented to simulate high-level petri net with xml be its tokens. XPNTool has the functions of workflow modelling,workflow modifying and model saving. Workflow models are saved as xml files so that they can be used on different workflow management platform. XPNTool implements the dynamic colored graph method proposed in this paper. The dynamic colored graph method is proved to be practicable and applicable with the example of hurried philosophers.