综合运输网络中合理路径优化模型

为了提高多式联运经营人运输决策的科学性和可行性,建立了一个含路径合理性约束的联合运输路径优化模型.从货运生产实践角度出发,提出了联合运输合理路径概念.基于联合运输的实现流程,指出除了运输效益最大化外,合理的换装序列和换装次数限制是联合运输路径选择和优化必须要考虑的另外2个重要特性.对于一般联合运输问题,研究了运输总费用的构成,即直线运输费用、节点中转费用和超期惩罚费用.通过构建直观的联合运输网络图,以总运输成本最少为优化目标,将多方式联合运输合理路径的选择和优化问题转化为含有超期惩罚因子的广义最短路模型,对模型的假设和数学形式做了详细的描述,并提供了简要的求解思路和参考算法.

Improved model for viable route in multimodal networks

To enhance the efficiency and feasibility in decision-making for multimodal transportation operator,an improved model with several constraints of optimality and viability for route selection in multimodal networks is established. After the analysis of general multimodal transportation process,the concept of viable route in practical perspective is put forward.Besides the transportation economies of scale,two additional characteristics of viable intermodal routes are identified: logical mode sequence and limited transfer times.For a given multimodal transportation problem,the structure of a full route's total cost is studied,which is made up of three parts: line-haul transportation cost,transfer cost in terminals and overdue punishment cost.A layered multimodal network diagram for routing purposes is built.The viable routing problem is then formulated as a generalized shortest route problem with penalty factor,aiming at minimizing the cost of the total transportation in multimodal networks.Assumptions and detail descriptions of the model are presented.Compendious solution thought and consultable algorithms are provided.