A Multi-City Simulation and Performance Comparison of Dynamic Ambulance Redeployment Models
The focus of this thesis is on dynamic ambulance redeployment for emergency medical services, which is the act of positioning ambulances in real-time, typically to reduce response times to emergency calls. There are many existing redeployment models in the literature, but it is not known which models perform best, as they are usually evaluated with different simulation models (if evaluated at all). We simulate a handful of existing redeployment models on a range of city models and varying conditions then compare their performance. To evaluate performance of the redeployment models, we create the first open source simulation and optimisation package for emergency medical services, named JEMSS. The simulations run quickly, requiring less than a second to simulate 100 days for a realistic city model. We present the simulation package and demonstrate how it can be used in a simulation-optimisation framework for the example problem of ambulance deployment, which assigns each ambulance to a home station. Then, we detail the city models currently included in JEMSS along with initial simulation results before moving on to the performance comparison of selected redeployment models. Finally, we consider an existing bound on optimal redeployment performance known as the cover bound and show how the bound can be improved for cities that queue calls. We also show how the cover bound can be modified to be tighter for bounding performance of a particular redeployment model.
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