Abstract
In this study, ambulance location problem, which is a significant research field in transportation in healthcare, is focused on. It is assumed that travelling time of vehicles between two demand points is uncertain and this uncertainty is represented as a crisp and as well as convex set. In order to deal with this uncertainty, robust counterpart approach, which is capable of providing conservatism, is employed. According to results of the simulation process, which is designed for the sake of benchmarking robust and nominal solutions, it can be easily claimed that conservative robustness is able to be achieved with significantly sufferable costs, even with no costs in most of the scenarios, by the proposed model. Ultimately, since robustness is one of the most important keywords for sustainability, on which discussions can be found in several parts of the text, this chapter is concluded with the claim that, by the proposed model, sustainability of transportation in healthcare is enhanced based on the adopted problem.
TopIn the literature, lots of works which proposed model(s) providing a plan for ambulance location problem can be encountered. According to considering an environment under certainty or uncertainty, previous works can be classified into two main classes: i. works considering environment under certainty; and ii. works considering environment under uncertainty. In this section, the works that consider environment under uncertainty are tried to be given due to their capability of dealing with uncertainty, which is almost always inevitable.
Since 1970s, some works attempting to develop a robust model for facility location problem for emergency vehicles have appeared. And then, some researchers proceeded the previous studies in 1980s and 1990s with new ideas. And finally, with the recent developments after 2000, the literature in this field has been shaped as in our day. Some of the most cornerstone works are tried to be given below.
One of the earliest works in this field is Swoveland et al. (1973)’s work in which probabilistic branch-and-bound (B&B) procedure was developed for the ambulance location problem.
Aly and White (1978) assumed the locations of incidents were random variables. The probability distribution for rectilinear travel time between a new facility location and the random location of the incident (
) was developed for the case of 
being uniformly distributed over a rectangular region. The impact of the proposed model was evaluated by outputs of the employed simulation model.