Ambulance Location Problem to Minimize the Number of Ambulances, Expected Response Time and Probability of Lost Customer Demand

Ambulance emergency systems in urban areas should have the fastest possible response time because delays in service delivery may result in death or serious injury to the patient. There are some locations that ambulances can locate them to cover customers' demand. Each customer point should be served by an assigned ambulance. There is a hospital that has several backup ambulances to cover customer's demands that have not been served. If the assigned ambulance is busy, the customer should be served by a backup ambulance of the hospital. According to the problem, two queuing systems are presented to employ for this problem. Customers call to the emergency center with an exponential distribution function. The service time ambulance is included the travel time from origin to destination, the stopping time of in the customer location, and the return time. A three-objective mathematical model is developed with objective functions of minimizing the number of ambulances, response time and lost demand to locate ambulances and allocate ambulances to customers. In this study, the expected response time of the emergency center and the probability of customers' demand lost is computed. Since the proposed problem is NP-hard, to solve the problem, NSGA-II algorithm is employed.

کلیدواژه ها:

Facility Location ، Queuing System ، NSGA-II ، Multi-objective ، Integer Programming