Research on Optimization of Terminal Cargo Integrated Pickup and Delivery for High-speed Railway Express
With the continuous growth of express delivery volume in China and the increasing customer demands for ex-press service level,the shortcomings of the traditional air express transportation with higher costs and more transportation restrictions,and road express transportation with high energy consumption and emissions are becoming increasingly obvi-ous,which restricts the further development of the express delivery industry.By using high-speed railway to undertake the trunk transportation tasks of express goods and optimizing the terminal pick-up and delivery network that connects high-speed railway with urban areas,transportation efficiency and customer satisfaction can be improved.Based on the design of high-speed railway express terminal pick-up and delivery network,this paper established a double-layer multi-objective optimization model with the upper layer of transshipment and lower layer of pick-up and distribution with the optimization objectives of minimizing transportation cost and maximizing customer satisfaction.Considering the multi-ob-jective characteristics of the model,a non-dominated sorting genetic algorithm,NSGA-Ⅱ,was designed and improved for solving bi-level optimization problems.The proposed method was verified,and the solution results show that the algo-rithm converges at 55.9 generations on average,and the final pareto optimal solution set includes 10 solutions with crow-ding distance around 0.5.Among these solutions,the highest satisfaction rate of meeting the requirement for high-speed railway next-day delivery is 97%,with the lowest of 92%,and the average of 94.3%.
high-speed railway expressterminal pickup and deliverybi-level programming modelNSGA-Ⅱ algorithmmulti-objective optimization