Modeling and performance analysis of medical services systems using Petri nets

This paper presents Petri net modeling and performance analysis of an emergency medical services system (EMS). Petri nets are chosen for their ability to describe and study discrete event systems that are characterized as being concurrent, asynchronous, parallel, nondeterministic, and/or stochastic. We construct ordinary and temporal Petri net models for EMS. The ordinary Petri nets are used to analyze such systems properties as deadlock freeness, resource boundedness, and reversibility. After ordinary Petri nets are built, time variables are then used to associate with transitions thus resulting in temporal Petri net models. The temporal Petri net models serve to derive system performance indices such as the effect of patient load on waiting time, effect of doctor availability on waiting time and doctor utilization. We focus our performance analysis on two cases: 1) all patients are in the same priority class, and 2) they have different priority classes. The approaches presented provide a hospital capacity planning, efficiency improvement and study of the static structure and dynamic flow of hospital