A strategic approach for the ambulance covering of the province of Friesland

In the summer of 1995 the University of Twente, commissioned by the Province of Friesland, carried out research into the consequences of alternative locations for ambulances. The approach to this research was based on a network model, which represents the area to be covered. With this model the attendance times for the ambulances can be determined based on a shortest route algorithm. The attendance time is the time between the dispatching of the ambulance by Central Alarm after an emergency call and its arrival at the patient. The attendance times are compared with the norm as described by the Dutch law. The research concentrated on the Southwest and Northeast of the Province. In view of the norm of 15 minutes for the attendance time, the proposed alternative in the Southwest is the closing of one site and the moving of another. This is feasible under the condition that there will always be well-trained manpower available at the stations, and especially at the site which is moved. In the Northeast the moving of one post and the closure of another has no disadvantages with regard to attendance times. These conclusions appear to give a reliable picture of the real-world situation based on a conservative approach with the network model used, and, that higher travel speeds than those assumed are possible. \u

Reliability, Covering and Balanced Matrices

The paper addresses a certain generalized covering integer program. The original application that motivated the study of this problem was an emergency services vehicle location problem. In this paper, we show that the same model can be applied to a general system reliability optimization problem. The main contribution of this paper is the definition and analysis of a reformulation strategy. Specifically, we show how the original generalized covering problem can be reformulated as a set covering problem. We then show that for a particular special case the associated constraint matrix is balanced. This in turn implies that the integer program can be efficiently solved using linear programming techniques. This result together with the good computational results reported in a previous paper constitute substantial evidence as to the overall effectiveness of the reformulation strategy. Furthermore, they indicate that the generalized covering model addressed can be effectively solved in a fairly wide range of cases