Study On Locating A Master Station Of Gas Station Based On Rescue

The master station is a service facility to provide oil distribution to sub-station; it stores a large amount of product oil which is extremely dangerous, it would affect lives and property security of residents who lives nearby once accident occurs. So the location of master station has become an important problem. The previous studies about the location of master station take minimizing total costs as one target, only considering accident risk, lack of the research of emergency rescue after the accident and the costs. Based on deficiencies of previous papers, we focus on locating a master station of gas station from the perspective of rescue on the basis of construction costs and transportation costs, consider rescue costs after the accident, and study on the master station’s location based on emergency rescue. Consider whether vehicle encounter blockage in the process of travelling, the model for master station’s location is established and show an algorithm for computing it, also give a location scheme to provide a theoretical basis for relevant departments planning gas station’s location. Main works and achievements of this paper are as follows.To the question of locating a master station of gas station from the perspective of rescue, vehicles travel following the shortest path in the situation of no blockage, consider emergency rescue after the accident, make the total costs (construction costs+transportation costs+rescue costs) minimal, the model of location is established. An approximate algorithm A is designed, demonstrate the time complexity is o(m2n), m and n denote the number of master station’s candidate and sub-station, respectively, then, analyze the approximation ratio. If the distance between each sub-station to master station and the distance between the rescue station to master station are small, the approximation ratio level off to 1. Finally, using the model and the algorithm analyze an example of Wuhan local network.To the question of locating a master station of gas station with path blocking and emergence aid, if vehicles travel following the shortest path in the situation of blockage, once the key edge is blocked on the shortest path, will bypass long distances. If select anti-blocking path to travel, although it is slightly longer than the shortest path, but even encounter blockage, rescue vehicles detour not long distance, also can arrive at the accident points within a short period of time. So select anti-blocking path to travel in the case of blockage, make the total costs (construction costs+ transportation costs+ rescue costs) minimal, the model of location is established. According to the actual situation, it is divided into two categories:one is that vehicles can reach the rescue points when passing round within the best time in the process of rescue, the other is that vehicles can not reach the rescue points when passing round within the best time, thus, can produce a very larger additional cost. According to two situations above, an approximate algorithm CA is designed, demonstrate the time complexity is o(m2n), m and n denote the number of master station’s candidate and sub-station, respectively, then, analyze the approximation ratio. If the block risk of anti-blocking path between each sub-station to master station and the block risk of anti-blocking path between the rescue station to master station are small, the difference between risk cost of unit distance and additional cost of unit distance is small, the approximation ratio level off to 1. Finally, using the model and the algorithm analyze an example of Wuhan local network.