Maximizing control flow concurrency in BPMN workflow models through syntactic means

Concurrency is a desirable property that enhances workflow efficiency. The purpose of this paper is to propose six polynomial-time algorithms that collectively maximize control flow concurrency for Business Process Model and Notation (BPMN) workflow models. The proposed algorithms perform model-level transformations on a BPMN model during the design phase of the model, thereby improving the workflow model’s execution efficiency.

The approach is similar to source code optimization, which solely works with syntactic means. The first step makes implicit synchronizations of interdependent concurrent control flows explicit by adding parallel gateways. After that, every control flow can proceed asynchronously. The next step then generates an equivalent sequence of execution hierarchies for every control flow such that they collectively provide maximum concurrency for the control flow. As a whole, the proposed algorithms add a valuable feature to a BPMN modeling tool to maximize control flow concurrency.

In addition, this paper introduces the concept of control flow independence, which is a user-determined semantic property of BPMN models that cannot be obtained by any syntactic means. But, if control flow independence holds in a BPMN model, the model’s determinism is guaranteed. As a result, the proposed algorithms output a model that can be proved to be equivalent to the original model.

This paper adds value to BPMN modeling tools by providing polynomial-time algorithms that collectively maximize control flow concurrency in a BPMN model during the design phase of the model. As a result, the model’s execution efficiency will increase. Similar to source code optimization, these algorithms perform model-level transformations on a BPMN model through syntactic means; and the transformations performed to each control flow are guaranteed to be equivalent to the control flow. Furthermore, a case study on a real-life new employee preparation process is provided to demonstrate the proposed algorithms’ usefulness on increasing the process’s execution efficiency.