Multi-objective Optimization Of Cold Chain Logistics Distribution Path Considering Time Tolerance

With the development of economic and social,people need more and more refrigerated food,which greatly promoted the development of cold chain logistics in our country,and brought cold chain logistics into a period of rapid development in our country.And new mode,such as "central kitchen + food cold chain distribution" and other new mode,is derived.Under the mode of "central kitchen + cold chain distribution",customers have higher requirement for cold chain logistics distribution service level and time.How to consider customers’ requirements on time and arrange distribution routes reasonably has significant significance for cold chain logistics enterprises to improve distribution efficiency and reduce operating costs.In view of the above content,this paper carried out a study of cold chain logistics distribution route considering time tolerance.Firstly,this paper summarizes the development status of the mode of "central kitchen + cold chain distribution" in our country,analyzes the advantages and disadvantages of cold chain logistics transportation under the mode of "central kitchen + cold chain distribution",and points out the future development prospects.Secondly,in view of the problems such as high distribution cost and difficult customer time window under the mode of "central kitchen + cold chain distribution",the cost composition of cold chain logistics distribution enterprises is analyzed respectively,and according to the sensitivity of customers to time,the concept of time tolerance and its quantitative method are proposed.Thirdly,a multi-objective optimization model of cold chain logistics distribution route was established with the goal of maximizing the customer time tolerance and minimizing the cost of cold chain logistics enterprises.According to the characteristics of the model,a Plant Growth Simulation Algorithm was selected.During the design,the Plant Growth Simulation Algorithm was improved by generating initial basis point of saving algorithm,adopting mixed random-fixed step size and elite strategy.In order to balance the interests of customers and enterprises,based on the distribution characteristics of Pareto frontier,the optimal solution selection method is used to select a scheme acceptable to both customers and transportation enterprises.Finally,a cold chain logistics company is taken as an example to verify the effectiveness of the proposed model and algorithm.The sensitivity analysis of the model parameter time tolerance index was carried out to verify the rationality of the value.In addition,30,50 and 100 customers in Solomon standard example were selected for further analysis.By comparing with NSGA-II algorithm,the superiority of the Modified Multi-objective Plant Growth Simulation Algorithm was verified.The research ideas and methods proposed in this paper can provide reference for reasonable distribution of cold chain logistics enterprises.It provides guarantee for the development of cold chain logistics under the mode of "central kitchen + cold chain distribution".