Sequential Location-allocation Problem Of Logistics Nodes With Curved Demands Considered

In recent years,China has focused on supporting the construction of transportation routes to meet growing national demand.The development of transportation is of great significance to society and economy.Railway construction is not only one of the most important strategies for China's economic and social development,but also an important part of the realization of the "The Belt and Road" initiative and "Going Global" strategies.Transportation engineering is a key construction project that will continue to grow in the future.Large-scale transportation projects such as railways require a large amount of raw materials during the construction process,including concrete,graded macadam,emulsified asphalt,turnouts,rails and sleepers,etc.It is necessary to build logistics nodes such as concrete mixing stations,graded crushed stone mixing stations,turnout storage yards,track laying bases and beam manufacturing yards to meet the material requirements of railway construction.Scientific and reasonable location of logistics nodes can reduce the total operating cost of transportation construction projects,increase profit levels,improve construction efficiency,and bring economic and social benefits.This paper studies the location problem of concrete mixing stations in railway construction projects.For railway construction projects,the demand for concrete materials is not concentrated at certain points,but is continuously distributed on the line.Such problem can be defined as facility location problem with continuous curved demand.In addition,the material requirements on the line change dynamically with time.In the initial stage of the project,the amount of material requirements is low.In the middle and late stages,large-scale construction is underway,and the demand for materials has increased rapidly.Therefore,the traditional one-time static site selection strategy causes the number and location of logistics nodes to not match the needs of dynamic changes,resulting in the loss of total logistics costs.This paper considers the continuous curved and dynamic demand in railway construction projects,then uses line integral function to characterize the demand density.The dynamic sequential location of logistics nodes is selected to reduce the total logistics cost while ensuring the level of logistics services.According to the characteristics of continuous curved demands and dynamic sequential location,combined with the demand forecast situation,this paper constructs the myopic optimal strategy model,long-term optimal strategy model and global optimal strategy model.By analyzing the model,this paper combined Voronoi diagrams to improve the algorithms such as the Alternate Location-Allocation(ALA)method,the Utility Function,and the addition method.In the end,this paper takes the construction of the inter-city railway project along the river along the south of Jiangsu as an example.This paper uses MATLAB2018 b to program and solve the optimal location and location sequence of logistics nodes.The total cost of transportation and the total capacity of the facility were used as measures.Comparing the strategies with the total logistics cost as the criterion,it is concluded that the sequential location strategy under curved demand can effectively reduce the total logistics cost.In the case of different demand forecasts,the most suitable sequential location strategy should be selected for the location of facilities.The paper provides a reference for the dynamic sequential location problem under curved demands.The paper consists of 32 figures,34 tables,and 81 references.