Study On Service Network Design Of CHINA RAILWAY Express Based On Time Values Of Multiple Categories Of Goods

CHINA RAILWAY Express has developed rapidly into an international logistic network across Eurasia with implementation of the Belt and Road Initiative.However,several severe problems,such as homogeneous competition,uncertain frequency and high logistic costs have created restrictions to CR Express and need to be solved by transport organization optimization.And goods with different time-sensitivities have different demands for timeliness or the service quality of CR Express.Therefore,it’s necessary to build up a safe,economic and effective service network of CR Express for specific categories of goods,combining the interests of customers and transport companies.Therefore,this thesis studied on service network design problem of CR Express based on time values of multiple categories of goods.First,this thesis did literature review and analyzed the current shortcomings and development tendency of CR Express.Operation modes were classified and it was found out that homogeneous competition,which is caused by blind expansion and lack of coordination,is the main cause of current shortcomings.Then,this thesis selected operation mode with single OD,mode with multiple O and single D for the researches on service network design of CR Express.Secondly,this thesis determined the core objective of service network design after analyzing customers’ transport demands and conceptualized the concept of integrated transport cost.Time value theory was introduced,then the calculation methods of time value ratio and its weight ratio were determined separately based on CL model and AHP method.This thesis divided the service network design problem into macroscopic and microscopic service network design problem according to their unique features,and corresponding description methods were also proposed.Thirdly,this thesis defined symbols of microscopic service network based on the description method.Microscopic service network design model was built up with the minimum integrated transport cost as the objective.Optimized ant colony algorithm was designed with introducing the concepts of necessity-point and forbidden point.Similarly,symbols of macroscopic service network can be defined and macroscopic service network design model was built up after derivation of the objective function.Then,this thesis designed optimized genetic algorithm to nest with optimized ant colony algorithm,for solving the macroscopic and microscopic service network design models synchronously.Finally,northern lines in CR Express western corridor were selected for case study.This thesis designed macroscopic and microscopic service networks separately for multiple categories of goods.Design results showed that,CR Express service network can raised the transport demand fill rate from 73.79%to 88.31%,and the transport demand fill rate of time-sensitive goods can be raised to 94.48%,which produced time values around 35526.556 yuan/TEU.And homogeneous competition problem can be alleviated and integrated transport cost of CR Express was reduced.Optimization effects were obvious and verified the validity of models and algorithms.