Integrated Optimization Of Depot Selection And Vehicle Routing For Treatment Of The Wounded In Urban Public Emergencies

With the rapid development of economy, the continuous expansion of the urban size and the growing density of population, it gets more and more severe to suffer from sudden public emergency. Thus, the prophylactic-therapeutic measures must be taken to prevent the outbreak of public emergency. And when it's unavoidable to prevent, the timely rescue measures must be taken to decrease the loss of people's life and property.The wounded are the prior object of rescuing when the emergency breaks out. Besides the influence of the condition of the injured, the survival rate depends more on the emergency treatment and the time it spent that the injured is sent to hospital, namely, the reaction velocity of emergency affects the survival rate directly. Considering the dynamic traffic condition in the urban area, the distribution of the first aid spots and its capability to rescue, the ability to treat the injured and capacity of the hospital of emergency network, this paper concentrates on the depot selection-routing problem on the basis of the following two situations:one is the one emergency-multi-depot selections while the other is several emergency- multi-depot selections, with the aim of rescuing all the injured in the shortest period of time.Firstly, a travel time calculation method of roads is proposed considering in the real-time and time-dependent, with the emulation comparison, and then the choice of a more efficient method to compute the model objective function of the main problem.Secondly, three strategies of the combinations of real-time and time-dependent are put forward, with the emulation comparison and then the choice of the best one that could increase the efficiency of decision.Thirdly, in connection with the situation of one emergency-multi-depot selection and on the basis of dynamic traffic conditions and the limited conditions of hospitals in the emergency network, there are two periods:in the emergency spots vehicles dispatching period, the aim is to treat all the injured in the spot in the minimum sum of weighted period of time; in the delivery of the injured period, the aim is to sending them to the hospital in the minimum sum of weighted period of time. It provides a method of combining genetic algorithm and linear programming technique to solve the two problems, and the validity of the algorithm is validated by a numerical example.Last but not the least, in connection with the situation of several emergency-multi-depot selection, there are two periods:one is the vehicles dispatch in the emergency spots and the other is the delivery of the injured. In the first period, it provides a method of combining genetic algorithm and linear programming technique to select the depot and vehicle routing, with the aim of treating all the injured in the spots in the minimum sum of weighted period of time; in the second period, it selects the hospital and the vehicle routing for the delivery of the injured with the employment of the method of genetic algorithm in the minimum sum of weighted period of time.