Logistics Node Location With Curved Demands And Lateral Transshipments

The railway construction project will continue to be the focus of domestic infrastructure construction for a long period of time in the future,and it still has a sustained and stable construction peak period.The investment in China's railway transportation construction is very alarming,and the proportion of material costs is as high as 60%.Scientifically selecting the location of logistics nodes can not only control the material cost occupation but also improve the material supply level.The demand for line construction materials is continuously distributed along the railway lines.For example,each location of the proposed line needs to be equipped with gravel,rails,cement,etc.,which is a realistic correspondence of curved demands patterns.In addition,there are some uncertain factors in the construction of railway lines,such as changes in construction technology,changes in engineering design,and improvement in project quality,which lead to the demand for line construction materials cannot be maintained at a steady state.In order to ensure the safe and efficient end supply and meet the demand of line construction materials with lower operating cost,this thesis studies logistics node location problem with curved demands and lateral transshipments.Logistics node location problem with curved demands and lateral transshipments is definted in this thesis.Firstly,the characteristics of line construction materials demand are introduced,and the end supply process of logistics nodes to meet the demand for line construction materials is described.Then,based on the inventory management problems of the logistics nodes,the lateral transshipment mechanism of the two logistics nodes is set.Finally,the density function of the line construction material demand is expressed as a piecewise function composed of several independent normal random variables,and the total demand for the construction materials of the two logistics nodes is calculated.Cost model of the logistics node location with curved demands and lateral transshipments is constructed and solved in this thesis.Firstly,the cost model is constructed.It obtains the logistics nodes location and demands allocation in a way that minimizes the total cost of the cost model,which is composed of downstream transportation cost,inventory cost and lateral transshipment cost.Then,the nature of the optimal position of the demand boundary point and the existence condition of the optimal position of the logistics node are analyzed.Finally,the demand density function is used to describe the demand for line construction materials that exist continuously along the line,and the total demand for line construction materials that each of the two logistics nodes needs to meet is calculated.Through the analysis of two cases in this thesis,it can be found that when the line construction material demand is very uneven in spatial dimension distribution,it is meaningful to consider the lateral transshihpment in logistics nodes location problem.Considering lateral transshipment can not only obtain better logistics node location and demand allocation decision,but also improve the economic benefits of logistics nodes.There are a total of 14 pictures,14 tables,and 53 references in this thesis.