Scientific paper ID 1306 : 2016/3

The paper focuses on the determination of the number of centres for outpatient emergency care and their coverage with respect to area and population within the specified by standards time framework. The study objective is to work out the minimum number and specific location of emergency medical aid centres securing maximum service (coverage) of the population as well as of the city territory, at set maximum time and / or distance. To determine the coverage by areas in the city of Sofia, it is necessary to apply certain mathematical models of centre location choice, the current report implementing the task of coverage (set covering problem), a task of mixed integer and linear programming. The target function and constraints and binary variables are defined in the Solver Add-in.

Sofia area is served by means of considering the Euclidean metric of distances between two points, corrected by a factor taking into account the road network, whereas the travel time needed is obtained by assuming an average city movement speed of ambulances.

Problem solution with а varying number of centres (2, 3, 4, 5) gives their location and coverage extent (population served) at pre-set time standards for medical triage (Code Red - 8 minutes, code orange - 20 min and code green – up to 120 min.).