Study On Optimal Decision Models For Emergency Material Allocation With Systemic Characteristics Analysis

As one of the most severe affected area, China suffered great losses from all kinds of natural disasters for a long period. With the objective of reduce disaster losses, recovering the social and economic order and ensuring the normal living condition of victims, central government and local authorities have made a great effort in disaster relief operation and management, especially the emergency logistics and emergency material reserves and allocation management. Most of the previous researches are all carried out without taking dynamic change in time (i.e. emergency material time-varying character), transportation capacity constrain, response time constraint and emergency response cost into consideration, results in the gap between theory research and actual operation requirement. While in reality, emergency material has a time-varying character in supply-demand, i.e. supply-demand character of emergency material will change in different relief operation phase, which is the main topic in this paper. So, starting with the supply-demand character analysis in emergency material allocation research has more sense of realistic value.Based on related research achievements, this paper focused on the core of emergency logistics operation in large-scale natural disasters, i.e. the material allocation model constructing and solving. With the summaries of the supply-demand characters, and the analysis of the decision objectives and constraints, optimal decision models were established, and computation algorithms were designed by feasible solution and optimum solution condition analysis. The main topics in this paper are as following:(1) With summaries in the connotation and systemic structure of emergency logistics and analysis of emergency material allocation's systemic characters, a basic idea of systematic research in this paper was proposed. In this idea, taking the earliest emergency response start time and the minimum number of relief material distribution center involved (short as R2DC) as bi-objective, the problem was decomposed into time-varying supply-demand constrained problem and non-time-varying supply-demand constrained problem in simple network and complex network structure, with emergency response cost constrain, response time constraint and transportation capacity constraint.(2) Non-time-varying supply-demand constrained problem was studied with two sub problems:emergency material allocation model with emergency response cost constrain and material allocation model with transportation capacity constrain. Firstly, by analyzing emergency response cost elements and considering emergency response cost as a modification as the assessment of the solutions, an optimal decision model for material allocation in emergency logistics with emergency response cost constrain was established and computation algorithm was designed. Secondly, the emergency response start time was defined as the time that the last relief material transported to the affected area and relief operation activity starts. With the analysis of the relationship among material supply amount, the available amount and the number of transportation repeated, material allocation model with transportation capacity constrain and optimized combinatorial algorithm were designed.(3) Multi-R2DC selection problem with time-varying supply constraint was studied. Firstly, the concept of critical response time was proposed. Based on the analysis of difference between theoretical critical response time and actual critical response time, and the relationship between critical response time and max transportation time, a multi-objective decision model for multi-R2DC selection with time-varying supply was established with an optimized combinatorial algorithm. Secondly, the methodology for multi-R2DC selection problem with time-varying supply constraint was applied into the non-time-varying supply-demand with transportation capacity constrain problem, and a new optimized combinatorial algorithm was designed(4) Time-varying supply-demand constrained problem was studied with two sub problems:multi-R2DC selection problem and single-R2DC and multi-affected-area emergency material allocation problem. Firstly, by analyzing earliest emergency response start time elements, and the difference between theoretical critical response time and actual critical response time, an optimal decision model for multi-R2DC selection problem with time-varying supply-demand constraint was established and computation algorithm was designed. Secondly, the methodology for multi-R2DC selection problem with time-varying supply-demand constraint was applied into single-R2DC and multi-affected-area emergency material allocation problem with time-varying supply-demand by topological structure transformation, and an optimized combinatorial algorithm was designed.(5) Single-R2DC and multi-affected-area emergency material allocation problem with time-varying supply-demand constraint and response time constraint was studied. Firstly, the scheme configuration of this problem was addressed. Secondly, based on the analysis of the relationship between system response time and response time constraint of each affected-area, a methodology was suggested by modification on scheme without response time constraint of each affected-area, and a corresponding algorithm was designed.(6) Time-varying supply-demand constrained problem in complex network structure was studied. Firstly, the scheme configuration of this problem with complex network structure was addressed. Secondly, based on the analysis of the relationship among system response time, earliest emergency response start time of R2DC and response time constraint of each affected-area, and the analysis the relationship between system response time and critical response time, a material allocation sequence was suggested, and a corresponding algorithm was designed.By studying the problems mentioned above, the decision-makers in disaster relief operation could be assisted to construct a systemic knowledge of emergency logistic and emergency material allocation, to gain intelligence supporting and decision-making reference for emergency logistics operating effectively to guarantee emergency material supply. Thus, the total emergency management system may realize the relief objectives with the earliest emergency response start time and the minimum number of R2DC involved, decline the impact caused by large-scale paroxysmal events and natural disasters on social life and minimize the total systematic loss on casualty and property.