Research On Optimization Of Location And Vehicle Routing Problem For The Dairy Products Cold Chain Logistics Based On Bi-level Programming Model

With the rapid development of China's economy,the quality of national life has been significantly improved,the demand for high protein-rich dairy products is also growing,but also to promote the rapid development of China's dairy cold chain logistics.Dairy products on the high degree of preservation requirements,short shelf life,the temperature and storage conditions are harsh requirements.Improper transportation and storage easily produce a variety of micro-organisms affect the quality of dairy products,thus threatening people's lives and quality of life.In order to ensure that consumers eat dairy products,quality and safety,the implementation of full quality of dairy products monitoring is particularly necessary.At present,China's dairy cold chain logistics has entered into the fine development of enterprises for the cold chain of dairy products in the distribution process more and more attention.Due to the particularity of dairy products and the geographical distribution between manufacturers and customers,the choice of suitable dairy cold chain logistics distribution center and the optimized distribution route can not only reduce the cost of cargo damage,ensure the quality and safety of dairy products,Product cold chain logistics of the overall operating costs,improve operational efficiency.The paper first analyzes the current situation of cold chain logistics at home and abroad,and elaborates the basic theory of cold chain distribution center location problem and cold chain vehicle routing problem,and then leads to the dairy product cold chain logistics distribution site-path optimization.Then,through the detailed description of the Bi-level programming theory,the model theory foundation is laid for the optimization of the routing problem of the dairy product cold chain logistics distribution.Next,based on the characteristics of dairy products,this paper introduces the concept of dairy cost and time window,and constructs a Bi-level programming model of dairy product cold chain logistics location-path optimization problem.The upper model determines the optimal distribution center location,the lower model determines the optimal distribution path,the interaction between the upper and lower layers,and finally the dairy product cold chain logistics to achieve the overall system optimization,the total cost of logistics to achieve the least.Finally,a hybrid algorithm combining genetic algorithm with ant colony algorithm is used to solve the model by MATLAB.At the same time,an example is given to demonstrate the effectiveness of the model.Through the research,this paper concludes that the construction of Bi-level programming model is feasible to solve the problem of site selection and path optimization of dairy cold chain logistics distribution center.The research results of this paper can not only provide the relevant basis for the dairy industry to reduce the distribution and consumption,but also provide reference for the dairy enterprises to improve the efficiency of the cold chain logistics operation,reduce the operating costs and strengthen the coordination between the supply chain.