Date of Award

8-2012

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Legacy Department

Industrial Engineering

Advisor

Mayorga, Maria E

Committee Member

Ferrell , William G

Committee Member

Kurz , Mary E

Committee Member

Taaffe , Kevin M

Abstract

The major focus of Emergency Medical Service (EMS) systems is to save lives and to minimize the
effects of emergency health incidents. The efficiency of the EMS systems is a major public concern. Thus,
over the past three decades a significant amount of research studies have been conducted to improve the performance
of EMS systems. The purpose of this study is also to improve the performance of EMS system.
The contribution of this research towards improving the performance of EMS systems is twofold. One area
is to implement optimal or near optimal dispatching strategies for EMS systems and the other is to determine
the response boundaries for EMS vehicles.
Proposed dispatching strategies are implemented incorporating the degree of the urgency of the call.
A Markov decision process (MDP) model is developed to obtain optimal dispatching strategies in less complex
models. A heuristic algorithm is proposed to dispatch ambulances for more complex models. In this
study, an integer programming formulation and a constructive heuristic are proposed to determine response
areas or districts for each ambulance. Additionally, dispatching rules to dispatch paramedic units within districts
and out of districts are examined.
Simulation is used to evaluate the performance of the EMS system after introducing proposed dispatching
policies. Performance is measured in terms of patients' survival probability rather than measuring
the response time thresholds, since survival probability reflects the patients' outcome directly. Results are
illustrated using real-data collected from Hanover county Virginia. Results show that proposed dispatching
rules are valuable in increasing patients' survivability

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