title: Methods for solving nonlinear equations used in evaluating emergency vehicle busy probabilities.
abstract: In this paper we present two iterative methods for solving a model to evaluate busy probabilities for Emergency Medical Service (EMS) vehicles. The model considers location dependent service times and is an alternative to the mean service calibration method; a procedure, used with the Hypercube Model, to accommodate travel times and location-dependent service times. We use monotonicity arguments to prove that one iterative method always converges to a solution. A large computational experiment suggests that both methods work satisfactorily in EMS systems with low ambulance busy probabilities and the method that always converges to a solution performs significantly better in EMS systems with high busy probabilities.
authors: University of Arizona, Tucson.
authors: J
authors: J
authors: Goldberg
authors: F
authors: F
authors: Szidarovszky
mesh_terms: D000465:Algorithms; D000552:Ambulances / Q000706:statistics & numerical data / Q000600:supply & distribution*; D003625:Data Collection; D004632:Emergency Medical Services / Q000458:organization & administration / Q000706:statistics & numerical data*; D005069:Evaluation Studies as Topic; D015233:Models, Statistical; D009874:Operations Research; D011336:Probability; D013996:Time and Motion Studies; D014195:Travel; D014481:United States; D016526:Workload