【摘要】 在轴辐式网络单分配模型的基础上,改变传统将规模经济效应处理为折扣系数常量的方法,建立了基于可变规模经济效应的非线性规划模型.将以流量为自变量的枢纽间非线性转运成本函数进行分段线性化,从而将其转化为混合整数线性规划模型,应用Gurobi进行求解.通过算例讨论了单调可变的规模经济效应对枢纽点选择的影响,研究了在p-Hub问题中p的变化对枢纽网络的影响.结果表明,建立的模型能够拓展于处理任意非线性规模效应关系.更多还原

【Abstract】 So based on a single allocation model of hub-and-spoke network whose effects of economies of scale are treated by constant discount factors,a nonlinear programming model is devised to present the nonlinear effects of economies of scale by the transported volume.The approach based on piecewise linearization on the nonlinear cost function of transported volumes among hub-hub trunks is applied.Therefore,the nonlinear programming model is transferred into a mixed-integer linear programming model,which can be solved by Gurobi.Compared to the method that uses constant discount factors to calculate the hub-hub transportation cost,the proposed model considers variable effects of economies of scale presents practical relations between the transportation costs and transported volumes.By the linearization method,this model can be effectively solved.In the experimental study,the paper analyzed the influences made by variable monotonous effects of economies of scale on hub selection and the influence of the selection of pin p-Hub problems on the design of hub network.The established model can be expanded to deal with any nonlinear effects of economies of scale.更多还原