The decision of which server(s) to dispatch to which customers is an important aspect of service systems such as emergency medical services. In this presentation, we present a model that uses mixed integer programming (MIP) and spatial queuing methodologies for identifying how to locate and dispatch ambulances through district design. The model maximizes the coverage level, i.e., the fraction of high-priority calls that can be responded to within nine minutes by locating ambulances at stations, assigning each call location to open ambulance stations according to a priority list, and balancing the workload across the ambulances. This district design approach identifies response districts for each ambulance that correspond to its primary and backup coverage regions, and contiguity is enforced for each ambulance’s primary coverage region. A computational example illustrates the modeling paradigm and solution algorithm using a real-world example. The results suggest that the reduction in coverage to maintain contiguity and a balanced workload among the ambulances is small. At the end of the talk, we will discuss issues surrounding emergency response during extreme weather events and natural disasters.
Laura A. McLay is an Associate Professor of Industrial & Systems Engineering at the University of Wisconsin-Madison. She received her Ph.D. from the University of Illinois at Urbana-Champaign. Her research interests are in the field of operations research, with a particular focus on discrete optimization with application to homeland security and emergency response problems. Dr. McLay’s research has been supported by NSF, DHS, and the Department of the Army, Sandia National Laboratory, and she has been awarded an NSF CAREER award. She has authored or co-authored 40 publications in archival journals and refereed proceedings. Her research has been awarded several honors, including four best paper awards. Dr. McLay is President of the INFORMS Section on Public Programs, Service and Needs (SPPSN). She is a Department Editor for IIE Transactions, and an Associate Editor for Risk Analysis and International Transactions on Operational Research. Dr. McLay is a member of INFORMS, IIE, the Society for Risk Analysis, Tau Beta Pi, and Alpha Pi Mu. She is the author of the blog “Punk Rock Operations Research” and is on twitter at @lauramclay.