Dynamic Monitoring of Service Outsourcing for Timed Workflow Processes

Service outsourcing for workflow processes has drawn much attention from researchers in recent years. Service outsourcing can not only improve the execution efficiency of workflow processes, but also reduce the overall costs and risks effectively. However, the existing methods neglect to consider the dynamic monitoring of the temporal constraints and the data transferring relationship of the activities among the local subplans or subprocesses of service providers in service outsourcing. As a result, the existing methods cannot propose solutions to temporal violations. In this paper, we propose a Petri net-based approach for dynamic monitoring of the temporal constraints of service outsourcing for timed workflow processes. As a widely used formal tool for modeling and analyzing the workflow processes, Petri nets can be used to design the structure of the workflow processes and provide powerful analysis techniques to verify the constraints. Specifically, we first propose a procedure to construct the Petri net-based fragments with data transferring of workflow processes. The monitoring mechanism of the temporal constraints is then set based on the fragments. Finally, we present algorithms for dynamically verifying the temporal constraints during the execution of fragments and repairing the temporal violations on the fragments. Compared with the existing methods, the proposed approach can construct fragments based on arbitrary service outsourcing results and provide optimal solutions to resolving temporal violations. Accordingly, the proposed approach can improve the efficiency of the exception handling in the workflow processes and reduce the overall operational costs.