The syntactical analysis of workflow model with loop structure

The process model of workflow is the primary and the most important aspect of workflow application. It is inevitable to introduce structural conflict during workflow model specification. But now workflow management systems lack an effective method to verify the workflow model with circular structure. The paper first defines directed cycle with semantic integrity (DCSI) according to workflow model structural character and proves the necessary and sufficient condition under which DCSI can construct circulation correctly, and then brings forward a method to reduce circular structure and a strategy to search all instance subgraphs of the workflow model. Basing on the instance subgraphs, we accomplish the process of analyzing and correcting syntactical errors of the workflow model. Furthermore, the validation analysis of the workflow model also can be accomplished by contrasting the instance subgraphs with the desired outcome of the workflow model. After that, we discuss the approaches to reduce the complexity of workflow model verification.