Abstract: Independent conflicts and concurrency in the modeling of workflows by using Petri nets are applied to the control of option processes and to keep a high-performance operation of systems. However, dependent conflicts and concurrency may lead to the incomplete and indeterminate conflicting behavior that produces difficulties for the analysis of conflicts. The phenomenon is called confusions that usually appear in workflow nets. In this paper, confusions are formalized as a class of marked subnets with special conflicting and concurrent restrictions in a Petri net. Then, a confusion detection algorithm based on confusion features is proposed and a policy is developed by using generalized mutual exclusion constraints to produce confusion prevention supervisors. Finally, experimental results of a classical workflow net by using the proposed algorithms show that the developed methods can detect and prevent confusions in workflow nets.

Key words: supervisory controls, Petri nets, workflow systems, confusions