Optimal Models And Algorithms For Joint Allocation And Transportation Of Relief Materials For A Large-scale Emergency

In recent years, with the frequent occurrence of public emergencies, the government, society and academe have attached high importance to emergency management. While a crisis occurring, much emphasis was put into the intergovernmental mutual cooperation in many countries, and the mutual cooperation was established in legal form so that emergency organization can quickly and methodically mobilize various resources. The central government launched emergency response in China in the emergency disposal of major public emergency, and carried out effective relief, reduced disaster losses and rapidly recovered under the unified leadership of the State Council and the support of the military and the inter-regional government. Emergency logistics was an important part of emergency response operation and was the foundation, prerequisite conditions of the relief activities conducting successfully, accordingly, the transportation of relief materials was a key link of emergency logistics, almost all of the major public emergency disposal, the large-scale transportation of relief materials was organized and implemented by inter-regional government to provide the necessary materials for the affected areas. However, most of the transportation problems of the relief materials were of materials distribution problems of the disaster areas based on the front-end scheduling system, lack of research on the integrated optimization problem in joint allocation and transportation of large-scale relief materials, seamlessly connecting to the distribution center of disaster areas based on the back-end scheduling system.We drew the useful experience of the emergency disposal from other countries for reference, which would facilitate further study of the actual situation of the intergovernmental cooperation emergency rescue, integrate effectively the intergovernmental emergency rescue force to play a synergistic effect of joint emergency rescue. Therefore, in this paper based on the joint allocation and transportation of inter-regional relief materials, the three key problems of integrated optimization were studied from the node, path and dynamic allocation point of view. The study mainly included the following:(1)Through analyzing the causes of operation inefficiency in joint allocation and transportation of large-scale relief materials based on the lean-collaborative logistics operation of integrated supply chain management, the three key problems of integrated optimization were discussed:transshipment nodes location problem, the problem of traffic control preferred path and dynamic allocation programming, and pointed out that these complex nonlinear transportation problems solving need to construct the effective heuristic algorithm, and that genetic algorithm was an effective tool to solve the complex combinatorial optimization problem.(2)Facility location and transshipment problem for the collector-distributor nature of transshipment nodes in large-scale, long-distance joint transportation were combined, and two location model for transshipment nodes of relief materials were developed. The location model objective was to locate the minimum number of transshipment nodes from the optimal operation of the entire transportation, while the location-allocation model objective was to locate the given number of transshipment nodes and to assign the affected cities from emergency service responsibility. Accordingly, a matrix-based co-evolutionary multi-objective genetic algorithm was proposed to solve the location model, and a matrix-baseb orientation mutation multi-objective genetic algorithm was also developed to solve the location-allocation problem with high-dimensional sparse matrix-based encoding and strong constraints. Moreover, due to the infeasible solution of violating constraints in the process of crossover operation, search space constraint strategy was adopted in the initialization.(3)According to the problem of traffic control preferred path in joint allocation and transportation of relief materials, the transshipment node's double function of supply origin and transshipment were considered, and two kinds of nonlinear functions were constructed: the node flow-based function and the arc flow-based function. In view of the above, the problem of traffic control preferred path was transformed into the nonlinear transshipment problem with node flow weight and arc flow weight, and a model of traffic control preferred path was developed to minimize the total costs and travel time. In the algorithm design process, in order to solve the defect of poor search ability and bad optimal result precision of the simple genetic algorithm, the cost matrix of optimization-oriented benchmarking information was considered to guide each individual to the fine local search space, and the numerical analysis results showed that many Pareto optimal solutions could be effectively obtained.(4)From the perspective of transshipment scheduling and inventory planning based on the continuous consumption of relief materials in the process of disaster rescue, a dynamic decision-making model for the dynamic allocation scheduling of relief materials was proposed to minimize the total scheduling costs, transportation costs and inventory costs. As for the large-scale nonlinear combinatorial optimization problem, higher mutation probability could strengthen local search ability. Therefore, a state matrix module-based scan mutation improved genetic algorithm was also proposed to solve the model. Numerical optimization process showed that the proposed genetic algorithm could obtain a better convergence performance.The joint allocation and transportation of relief materials should be rationally planned, which would make for the rapid restoration to the affected areas of social, economic and life order under the unified leadership of the central government and the support of inter-regional government. With the gradual improvement of emergency management system, research on the integrated optimization problem of joint allocation and transportation of relief materials will promote the construction of intergovernmental collaborative emergency operation system.