Research On Logistics Node Location With Curved Demands Considering Polygonal Obstacles

In the next few years,the construction of large-scale transportation routes,such as railways,highways,urban railways,inland waterways,oil and gas pipelines,will remain the focus of China’s infrastructure planning.The route construction projects bring a wide variety,large number of material demand.Therefore,a certain scale and quantity of logistics nodes need to be laid out to complete the storage and transportation of materials.The location of the logistics nodes need to consider the construction cost,facility size,traffic conditions,natural environment and other factors.In order to save logistics costs,ensure service level and improve transportation efficiency.The complex topography and geological conditions in some areas are not suitable for the transportation of goods.Logistics nodes need to avoid these impassable areas when providing service to the demand lines.Most of classical location theories and methods are aimed at discrete points,while the material demands are dimensionally continuous in routes construction.The research on curved demands location problem is not abundant.In the existence of obstacles,the classical location models and algorithms cannot effectively solve the facility location problem for curved demands.There is a lack of research on taking both the obstacle area and curved demands in consideration.In this paper,a logistics node location problem with curved demands considering polygonal obstacles is discussed.The research extends the field of location for curved demands,and also enriches the theory of location with obstacles.Because every points on the route have the material demands,in order to ensure the completion of construction project,the selected logistics nodes must be able to serve the whole route.Therefore,the barrier distance is introduced to establish the set covering model,which object is to selected the least amount of logistics nodes with a given service radius,under the premise of the whole demand route was covered.Two algorithms are proposed,the one is an integer programming model based on the generalized cover circle.another is define the service areas of each nodes by the Obstacle Voronoi diagram using the crystal generating method,then a heuristic algorithm is designed to gradually remove the nodes,and get the optimal solution.After comparing the advantages and limitations of the two methods,the ballast storage yard location about the construction project of YuMo railway is discussed as an example.The empirical researches demonstrate the practicability and effectiveness of models and approaches in this dissertation,provide a feasible solution and reference to solve the logistics node location problem for curved demands with polygonal obstacles.