Hub Location-allocation Problem With Time-definite Deliveries And Time-varying Traffic

With the rapid development of society and the continuous improvement of economic level,people’s expectations and requirements for logistics services are getting higher and higher.Meanwhile,along with the continuous promotion of economic globalization,cross-border logistics has gradually become a hot topic.International logistics enterprises have ushered in a wide range of development opportunities,but also face higher operational challenges.The layout of the logistics network is the core strategic decision of international express enterprises.Adjusting the existing international express network structure and building distribution hubs on the basis of existing facilities,and bringing economic benefits through centralized distribution can help enterprises achieve savings in transportation costs.As the key nodes in the logistics network,the reasonable location of hubs and express flow distribution has a significant impact on enterprises to reduce transportation costs and improve operational efficiency.International express business has the characteristics of strict timeliness,and involves the handover of various modes of transport.In order to ensure customer satisfaction and maintain service level,there are corresponding schedules for transferring express between different nodes,and the delivery time of express is more stringent.However,in the traditional research on facility location allocation,most scholars only consider the situation that the vehicle transit time is constant and known,ignoring the impact of realistic factors such as peak hours on traveling speed,which makes it difficult to ensure the smooth handover of express and stable service timeliness.Therefore,this paper aims to comprehensively consider the logistics service level of the enterprises,the impact of the actual road network on the vehicle traveling time and other factors,study the location decision of the distribution centers,optimize the structure of the existing logistics network,so as to achieve the purpose of reducing the operating cost and maintaining the service level.The paper firstly introduces the research problem from the realistic and theoretical background,briefly introduces the research method and content,reviews the classical location research,the location problem considering time-limited delivery and the related research progress considering time-varying traffic,and systematically elaborates the basic model of the classical location problem and the related classification of the hub location problem.Secondly,based on the p-median problem,a model is constructed for facilities location and distribution of goods flow considering time-definite deliveries and dynamic changes in the on-road speed of vehicles in a complex road network,with the objective of minimising total transport costs.Finally,a genetic algorithm is proposed to solve the model.In this paper,the model and algorithm are applied to the study of the location of the distribution hubs and cargo flow distribution in the southern regional network of D International Express Company.The optimal location of its distribution hubs and the results of cargo flow distribution are solved by MATLAB programming to verify the validity of the model and algorithm.And the corresponding results are derived and analyzed according to the factorial experiments to illustrate the effects of delivery time constraints,vehicle travel speed in time-varying traffic,and the number of distribution hubs on the location of the distribution center and express flow distribution.The results obtained can provide some theoretical basis for the optimization of the logistics network of international express enterprises.In addition,there are 18 figures and 10 tables in the dissertation.And 69 documents are referred to.