The Delivery Routes Optimization Research Of Urban Cold Chain Logistics Under A Green Perspective

With the improvement of the residents' life levels and eating habits,the demands of the residents for multi-variety of cold chain commodities are increasing year by year.As an important industry to meet the daily life of the residents,the cold chain logistics shows a vigorous development trend.According to the statistics of 2015,a large number of products which market values exceed more than 3.5 trillion need to be circulated through the cold chain logistics in China,and the year-on-year growth is more than 20%.Conservative estimation,the size of China's cold chain logistics market is more than 180 billion.Therefore,speeding up the development of the cold chain logistics is of great significance to the modernization of China's agricultural products circulation and agricultural development.However,the logistics industry based on transportation is recognized as one of the tradition large energy consumption,the cold chain logistic is an important branch of the logistics industry,it will consume more energy and produce more carbon emissions in the process of delivery.Under the background of global warming,the contradiction between the large energy consumption of the cold chain logistics and the calling for energy saving and emission reduction is prominent.In order to reduce the carbon emissions in cold chain's delivery process,this paper analyzes the cold chain delivery system under the perspective of a green perspective.For the cold chain logistics adopting multi-temperature joint delivery,this paper studies vehicle routing problem and inventory routing problem of urban cold chain delivery,then the corresponding mathematical models are built and the corresponding algorithms are designed.The main contents of this paper are as follows:(1)Starting from the urban cold chain delivery system under the perspective of low carbon,this paper makes a clear definition of carbon emission measurement,multi-temperature joint delivery,the deterioration of the cold chain commodities and vendor-managed inventory.Then it also analyzes the urban cold chain delivery problem under the perspective of low carbon in detail,including the specific characteristics analyses of cold chain logistics,the modes analyses of cold chain logistics and the key factors analyses of carbon emissions which affecting cold chain logistics.(2)Focus on the cold chain problem of multi-temperature joint delivery with multi-vehicle and multi-cargo,this paper proposes a carbon emission calculation method of cold chain's multi-temperature vehicle from the perspective of vehicle energy consumption,and introduces the temporal-spatial distance metric into initial paths construction.Then,an optimization model of cold chain delivery routes considering carbon emission and temporal-spatial distance is built,and a two-phase heuristic algorithm is constructed to solve it.In the heuristic algorithm,based on the clustering idea of k-means,appropriate vehicles are chosen for delivering in accordance with the proximity policy and an improved simulated annealing algorithm is proposed for the optimization of initial paths.It increases the memory function,designs the adaptive cooling mode and adds a multi-neighborhood operation into traditional simulated annealing algorithm.Finally,the results of examples demonstrate the validity of the algorithm.(3)In order to make integrated decisions for a two-echelon cold chain system which consists of a single supplier and multiple retailers under the background of low carbon,this paper studies the inventory-routing problem of the system with three-parameter Weibull deterioration under VMI,through adopting(T,q)inventory strategies and multi-temperature joint delivery strategies,selective analyzing the main costs of the system and proposing a cold chain system's carbon emission calculation method from the perspective of energy consumption.Then,a low carbon cold chain inventory-routing model with multi-period and multi-cargo according to the aim of minimizing the total costs is built and a two-layer genetic algorithm for solving the model is designed.This paper studies the cold chain logistics delivery problem with multi-cargo,the research stretches from a single period vehicle routing problem to a multi-period inventory routing problem,and it also stretches from a linear mathematical model without considering the deterioration rate to a non-linear mathematical model considering the deterioration rate with Weibull distribution,the research depth and difficulty increase gradually.To minimize the total costs,this paper optimizes cold chain logistics delivery with multi-temperature joint delivery as a whole,and which has a certain theoretical and practical significance.On the level of theory,it expands and enriches the related theories and methods of cold chain with multi-temperature joint delivery,on the level of practice,it provides a lot of inspirations and references for cold chain enterprises enhancing the operational capability with new technologies and new modes.