Timed Petri Nets as a verification tool

This paper presents Timed Petri Nets (TPN) as an analytical approach for verification of computerized queueing network simulation models at steady state. It introduces a generic approach to decomposing a queueing network into separate and independent TPNs, each representing a resource of specific type, such as a processing resource or a transporting resource. A decomposed TPN model enables a quick calculation of the resource expected utilization at steady state thus providing a stick yard against which to verify its long run simulation based utilization estimate. A factorial experimental design frame is applied to investigate the conditions and assumptions affecting the accuracy of the TPN decomposition, as compared to the simulation results. The relatively low differences obtained between the numerical results of the two methods provide evidence that this TPN technique can be used to verify simulation models. Eventual flaws in the computerized simulation model can be detected through observed discrepancies between the TPN based and the simulation results.