Modelling Workflow Patterns Based on P/t Nets

The formalization of patterns is a basic theoretical problem of workflow. Based on the WfMS’s concepts and the characteristics of workflow, we present some new concepts to help modelling patterns. Moreover, Logic is the control semantics of patterns and is stable and general, and to formalize patterns, we abstract logic from workflow and discuss how to model logic of patterns. With comparing and analyzing patterns’ logic, we specify patterns with the classical P/T nets without additional elements. Based on our method, the number of patterns is reduced and the specification of patterns is simplified significantly. Furthermore, a algebra method with synchronic distance is also presented to specify patterns. Accordingly, the patterns are also described by synchronic distance based on the P/T nets specification.