综合运输体系下快捷货运网络流量分配优化模型及算法

Multi-modal Express Shipment Network Routing Optimization Model and Algorithm

研究综合运输体系下快捷货运网络流量分配优化问题。基于服务水平的概念构建综合运输体系下的快捷货运网络,网络中包含运输方式、服务水平各不相同的多种运输服务。给出一种求解联弧权重均为正值的有向网络中任意两点间k短路的Double-sweep算法,并对通过联弧时间为随机变量的情况进行讨论,该算法以VisualC++语言实现。以网络中两点间k短路作为可选径路集,构建快捷货运网络流量分配优化模型,模型在满足需求服务水平的前提下以成本最小化为目标,且考虑了交通运输系统的外部影响。模型可采用Lingo 8.0进行求解。若干算例表明,给出的模型及算法可以用于求解实际规模的问题。

The multi-modal express shipment network routing problem is investigated in the paper. The express shipment network, including different modes and levels of transport service, is constructed on the basis of the concept of the express shipment service level. The double-sweep algorithm is presented to obtain the k-shortest path in a directed network with positive weight of all arcs and is implemented by Visual C＋＋. Based on the k- shortest path set between each OD, the multi-modal express shipment network routing optimization model is proposed. The objective of the model is to minimize the total cost under the premise that the service level of each demand is met. The model also takes the externalities of the transportation system into consideration. Lingo 8.0 is used to solve this model. Several numerical examples demonstrate that the method presented in the paper can be a promising way to solve real-size problems.