Approximating performance measures for public services

This paper deals with estimating performance measures, such as average response time for spatially distributed networks. Demands are generated stochastically at the nodes and the service units are stationed at service centers when available. Whenever a call arrives, a service unit will travel to the call´s location. When there are no available servers, the call will enter an infinite capacity queue at that node. The service units will travel from node to node serving the calls and return to the service center only when there are no more calls waiting. In most cases, exact models are too complicated to analyze. This paper presents approximations which are tested using simulation and found to give good results.