考虑支线运输服务的多式联运网络优化

在多式联运网络优化的同时一并对支线运输服务方案进行综合决策,提出Ⅱ阶段决策方法。模型第Ⅰ阶段表述为0~1整数规划问题,对网络设计以及网络流运行进行规划,基于阶段Ⅰ的优化结果提出第Ⅱ阶段决策过程,表达为带时间窗的支线车辆路径问题。针对模型的Ⅱ阶段结构特点,以两个阶段相互影响和反馈为求解思路,设计以交叉熵为主体的启发式算法,采用算例分析方法证明模型和算法的有效性,最后将Ⅱ阶段优化模型与两个阶段分别优化进行对比,指出在模型与算法参数均一致的情况下可降低成本73%。

Multimodal transport network optimization considering branch transport services

A two-phase programming formulation is proposed for the simultaneous decision of multimodal hub-and-spoke network design and routing service management. In Phase Ⅰ, the problem is described as 0-1 integer planning, which deals with the network design and the operation of network flows. Based on the optimized results in Phase Ⅰ, the decision process is proposed for Phase Ⅱ, which is described as the routing problem of the branch vehicles with time windows. A cross entropy-based solution method is proposed to solve the problem according to the structrural characteristics of the two-phase programming model, considering the the solving approach of the interaction and feedback between the two phases. A case application analysis is carried out to verify the effectiveness of the model and the algorithm. A comparison is done to the method of this two-phase optimization model and the traditional two separate stage optimization method. The result is that the total cost of the system can be reduced by 73% with the new model when the models and the parameters are identical.