Service level commitment in location models with stochastic demands and congestion.
Published: 2005
Language: eng
Number of pages: 169
Description: Customer satisfaction is one of the most fundamental issues for services. However, due to the limited amount of resources, the proper role of a service system planner is to balance between the service levels achieved and the cost incurred. This thesis deals with the most critical strategic decisions for services, facility location and resource allocation, under a stochastic environment.We focus on set covering-type problems minimizing the total number of servers on a network subject to service level constraints. We first consider a dynamic service discipline under which a call is assigned to servers based on their availability. Due to the complexity of the problem, most researchers have attempted to approximate service levels. We demonstrate that models in the literature often overestimate the achieved service levels and their solutions fail to satisfy the required service level. We turn our attention to developing both accurate and "safe" approximations for service levels to propose new models based on these bounds. Computational experiments show that the proposed models keep the total number of servers on the network still competitive compared to those of the reviewed models.Some location models employ a static service discipline under which a service call is assigned only to servers at its designated facility. We compare the dynamic and static disciplines to see how they differ in terms of the total number of servers on a network. We show that one of our models under a dynamic discipline always places at least as many servers as a counterpart under a static discipline.We extend one of the models to develop two models with two call classes especially for urban emergency medical services. One model employs a dynamic discipline for both call classes and the other does a combined discipline that priority calls are assigned to servers according to a dynamic discipline and yet regular calls according to a static discipline. The model with a purely dynamic discipline always places at least as many servers as that with a combined discipline. We observe that a well-chosen service discipline can reduce the total number of servers on a network.
Notes: Source: Dissertation Abstracts International, Volume: 66-10, Section: A, page: 3717.

Thesis (Ph.D.)--University of Toronto, 2005.

Electronic version licensed for access by U. of T. users.