Modelling inter-task dependencies and control of workflow managements systems based on supervisory control theory

A workflow is a computerized facilitation or automation of a business process, in whole or in part. Workflow Management Systems integrate humans, computer systems, information resources and organizational processes to provide a unified solution. With rapid increases in application domains that use Workflow Management Systems, it is essential to provide comprehensive and formal modelling approaches that can be used by various workflow software product developers to implement such systems. In this paper, a novel approach to modelling workflow systems based on Discrete Event System and Supervisory Control Theory is introduced. Supervisory controllers that are shown to guarantee desirable properties related to the execution of workflow processes are defined. Both centralized and decentralized supervisory controller designs are considered in order to address computational complexity and scalability issues.