Using the C_net for Formalizing Workflow Patterns

The essence of workflow systems is workflow patterns. Languages based on Petri nets perform better when it comes to state-based workflow patterns. However, some patterns with complex semantic can not be described by Petri-net. C_net was proposed for improving Petri nets in expressiveness of complex data structure and computing method of data value. C_net extends the Petri-Net through adding some new elements and the corresponding mechanisms. C_net can be applied in workflow modeling. In this paper, we use V element and C relation of C_net for describing instance runtime data and complex relation of computing and communication. Soundness of an C_net can be converted to the analysis of throughness and well designedness. All workflow patterns can be directly described using C_net. This paper investigates the issue and introduces a collection of workflow patterns formalizations, each with a sound formal definition and execution semantics. An application example is also given which includes most workflow patterns. The formalizations can be used as a foundation for pattern-based workflow execution, reasoning, and simulation as well as a basis for future research on theoretical aspects of workflow.