| In recent years,frequent disasters around the world have seriously hindered the development of countries all over the world,and brought serious property losses and even life dangers to human society.Due to the suddenness of natural disasters,the size and impact of disasters are Uncertain,however,in terms of site selection of traditional emergency logistics distribution center facilities,most models are constructed based on deterministic parameters,but in real life,there may be coordination between site selection of emergency facility distribution centers and various disaster points.However,due to problems such as poor reliability and low distribution efficiency,it cannot meet the needs of disaster relief.Therefore,in order to solve the above problems and improve the efficiency of emergency rescue,We consider various problems of emergency logistics distribution center location selection under uncertainty,the main contents are as follows:First of all,the research background and research significance are expounded,and the domestic and foreign status quo of facility location selection is sorted out.It is specifically divided into two aspects: facility location selection under certain conditions and facility location selection under uncertain conditions.Then it introduces the related theories of emergency logistics,mainly including the definition and characteristics of emergency logistics,the composition of emergency logistics network and emergency logistics network system.At the same time,the emergency logistics site selection model is analyzed in detail,and the robust optimization theory is selected to solve the uncertain parameters in the model,and the robust optimization method is explained,and several commonly used robust optimization methods are further introduced.Based on the above theoretical work,the site selection model and conclusions of the emergency logistics distribution center under uncertainty established in this paper are as follows.Secondly,by introducing two uncertain factors of demand and transportation cost,the robust model of single uncertainty is discussed respectively,and then the robust optimal facility location model under two mixed uncertain conditions is discussed,introducing customer demand and unit For the uncertainty budget level of transportation cost,a relatively novel robust optimal location selection model in which two uncertain parameters exist in the form of product is constructed.The established nonlinear robust optimization model is transformed into a linear mixed integer programming model through robust optimization theory and mathematical theory,and is solved by calling CPLEX through MATLAB.Finally,by randomly generating numerical values and constructing examples to analyze the influence of the robust optimization level on the numerical results of the model,the effectiveness of the algorithm is proved.Finally,consider the problem of facility location selection with and without capacity constraints in the case of facility interruption,and represent the situation of facility interruption by referring to an uncertain set,and introduce the total cost weight parameter,aiming at the minimum transportation cost and penalty cost,establish A two-stage robust optimization model is proposed,in which the first stage is to determine the location of the model state,and the second stage is to select the location where the facility is interrupted,and then introduce dual variables.According to the strong dual theory,the model is transformed into a mixed integer programming,Using the C&CG algorithm,based on the real data of 15 counties and cities in northwestern Sichuan,use MATLAB software programming and call the CPLEX solver to solve the problem,and display the optimal location layout of the obtained results on the Arcgis software.The results show that the capacity-limited robust optimization model is superior to the non-capacity robust optimization model in terms of the number of iterations,the percentage difference between upper and lower bounds,computing time and total cost.Therefore,decision makers can choose facilities with capacity constraints as much as possible according to the actual situation,so as to improve the overall emergency rescue efficiency.Through the relevant research on the location selection of emergency logistics facilities mentioned above,it can enrich the theoretical knowledge of emergency logistics location selection,improve the weak links of location selection in emergency logistics systems,and enhance the application of robust optimization theory in the location selection of emergency logistics distribution centers,which is conducive to helping the smooth progress of disaster relief work. |
