Research On Logistics Node Location With Curved Demands Considering Time Penalty Cost

With the implementation of the Belt and Road Initiative,transportation plays an important role in influencing the economic structure and leading the evolution of the economic pattern.It will promote the transportation infrastructure construction projects to maintain a sustained growth status for a long period of time in the future,and will put forward higher requirements on the material supply.In the construction of traffic routes,the materials are often transported from the pre-established logistics nodes to the road sections to be constructed.Therefore,the scientific layout of logistics nodes can ensure the reasonable supply of materials,enhance the service efficiency and reduce the project costs.For the construction of transportation routes,the demands of materials are distributed along the traffic routes which means the material demands show a continuous linear distribution.This problem is different from that where demands are distributed on discrete points.This problem is defined as curved demand logistics node location problem where the demand of service nodes is a function of a certain curve.In addition,in the facility location problem,more attention should be paid to the material whose performance changes a lot over time such as concrete,compared to other materials with stable performance.Therefore,in order to solve the problem of material allocation of transportation construction project better,the paper takes the time factor into account and does research on curved demand logistics node location problem.Based on the definition of the problem,the paper firstly introduces the demand density function,uses the line integral to express the demand of a line,and then builds up a transportation cost function which is related to the demand density function,the downstream transportation rate function and the distance function.At the same time,on the basis of summing up the time penalty function,combined with the performance characteristics of concrete,a penalty function form reflecting its performance change is proposed.Furthermore,the paper constructs a single logistics node location model including transportation costs and time penalty costs.Based on the analysis of the character of this model,the paper uses differential method to solve this model,and then in the example,iteratively obtained the optimal location of the facility.On this basis,a multi-logistics node location model is further established.The paper designs an algorithm combined the Voronoi diagram theory with ALA algorithm to solve out this problem.Finally,the case of location of concrete mixing station on Zheng-Xu high-speed rail is analyzed.The paper uses Matlab 2014b to find the location of the best logistics node,which verifies the feasibility of the proposed model and the designed algorithm.It provides a feasible solution and reference for the location of logistics nodes for time-sensitive materials.