Multi-objective Location Routing Optimization For Joint Distribution Of Fresh Dairy Products

In recent years,people’s living standards have gradually improved,and the fresh industry has also achieved rapid development.In addition,consumers have higher and higher requirements on the timeliness of fresh products,which makes the fresh product distribution center location and cold chain logistics distribution cause enough attention of enterprises.However,the fresh cold chain logistics is facing many problems,such as many logistics nodes,long distribution routes,unreasonable distribution route selection,and so on.As a mature leading industry in the fresh industry,the fresh dairy industry also has the above problems,and the fresh dairy products have strong fresh activity,short shelf life and are prone to deterioration.Therefore,professional refrigeration equipment and scientific distribution and storage methods should be adopted to effectively ensure the taste and quality of fresh dairy products.In the future,joint distribution,comprehensive optimization of location and route will become the trend of logistics distribution of fresh dairy products.Taking the joint distribution of fresh dairy products as the research object,this thesis studies the location routing multi-objective optimization problem of two-level vehicle cold chain logistics.Firstly,the research status at home and abroad is reviewed and summarized,and the research content and ideas of this thesis are put forward.Secondly,the related concepts,characteristics and classification of fresh dairy cold chain logistics,distribution center location,path optimization,and joint distribution are elaborated,which lays a theoretical foundation for the construction of the model and the design of the algorithm.Then,it analyzes the components of the total cost of two-level vehicle distribution in cold chain logistics,including the operation cost of distribution center,fixed cost of vehicle,transportation cost,refrigeration cost,damage cost and penalty cost.On the basis of constructing the deterioration rate function and customer satisfaction function,the thesis takes the lowest total cost and the highest customer satisfaction as the objective function,and constructs the multi-objective location routing optimization model of joint distribution.Thirdly,this thesis designs a two-stage heuristic algorithm to solve the model.The first stage is to combine the PSO algorithm and BAS algorithm,designs the PSO-BAS clustering algorithm to cluster customers,and selects the optimal number of clusters by contour analysis.The second stage is to improve the NSGA-Ⅱ algorithm combined with the differential evolution algorithm,so as to solve the multi-objective location path model.Finally,taking W company and G company as an example,this thesis collects relevant data,calculates the distance by transforming longitude and latitude coordinates through MAPGIS software,and then uses the designed algorithm to cluster and solve the model,and obtains the location path optimization scheme,which is compared with the single distribution,which has a certain reference value for enterprises to reduce costs and improve customer satisfaction.