Friday, February 6, 2015
10:30 AM - 11:30 AM
Room 1518
This paper studies the problem of simultaneously locating trauma centers and helicopters. The standard approach to locating helicopters involves the use of helicopter busy fractions to model the random availability of helicopters. However, busy fractions cannot be estimated a priori in our problem because the demand for each helicopter cannot be determined until the trauma center locations are selected. To overcome this challenge, we endogenize the computation of busy fractions within an optimization problem. The resulting formulation has non-convex bilinear terms in the objective, for which we develop an integrated method that iteratively solves a sequence of problem relaxations and restrictions.
Specically, we devise a specialized algorithm, called the Shifting Quadratic Envelopes algorithm, that 1) generates tighter outer-approximations than linear McCormick envelopes, and 2) outperforms a Benders-like cut generation scheme. We apply our integrated method to the design of a nationwide trauma care system in Korea. By running a trace-based simulation on a full year of patient data, we find that the solutions generated by our model outperform several benchmark heuristics by up to 20%, as measured by an industry-standard metric: the proportion of patients successfully transported to a care facility within one hour.
Our results have helped the Korean government to plan its nationwide trauma care system.
More generally, our method can be applied to a class of optimization problems that aim to find the locations of both fixed and mobile servers when service needs to be carried out within a certain time threshold.
Bio: John Turner joined The Paul Merage School of Business in 2010 as an assistant professor of Operations and Decisions Technologies. He holds a Ph.D. in Operations Research from the Tepper School of Business, Carnegie Mellon University. For his doctoral work titled
Ad Slotting and Pricing: New Media Planning Models for New Media , Turner was honored by
INFORMS with the 2011 George B. Dantzig Dissertation Award . This award is given for the best dissertation in any area of operations research and the management sciences that is
Van Munching Hall ▫ Room 4306 ▫ Telephone 301-405-8654 ▫ College Park, MD ▫ University of Maryland

innovative and relevant to practice. More recently, Turner was named a 2012 Yahoo! Faculty
Research & Engagement Program Scholar for his work in planning and scheduling online advertising, and was awarded the 2014 INFORMS William Pierskalla Best Paper Award in
Health Care Management Science for his work on designing a trauma care system in Korea.
Turner's research interests include applied optimization, large-scale optimization, revenue management, media management, health care management, and problems that lie at the interface of operations and marketing. His research has been published in leading journals, including
“Scheduling of Dynamic In-Game Advertising” in the journal Operations Research , “Planning of Guaranteed Targeted Display Advertising” in Operations Research, “Simultaneous Location of Trauma Centers and Helicopters for Emergency Medical Service Planning” in Operations
Research, and “A Large U.S. Retailer Selects Transportation Carriers under Diesel Price
Uncertainty,” in Interfaces
Van Munching Hall ▫ Room 4306 ▫ Telephone 301-405-8654 ▫ College Park, MD ▫ University of Maryland