航道等级差异影响下轴辐式航运网络优化
Optimization of Hub-and-spoke shipping network with waterway grade accounted in
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摘要: 航道是航运发展的关键要素,航道等级差异会给船舶通航带来一定的阻抗。在轴辐式网络单分配模型的基础上,考虑由航道等级差异造成的船舶转驳,建立最小化运输成本和转驳流量的双目标规划模型,并使用ε-约束算法进行优化求解,通过算例实验验证了模型的有效性。实验结果表明,航道等级差异对航运网络结构和航运效益影响显著。当航线船型固定时,为提高网络通航率,枢纽点可能选址在干支航线等级差异较小的节点,致使运输成本大幅增加;若考虑改变航线船型,则航道等级差异的影响减弱,运输成本可控制在合理范围内。Abstract: A double objective planning model aiming at minimizing shipping cost and cargo transferring volume is built and solved with constrained optimization algorithm. The model is verified through an example calculation. The research shows the significant effect of waterway grade level to shipping network structure and the efficiency. For given ship type, if the hub node is selected to ensure small grade difference between trunk route and branch route for efficiency, the shipping cost may go up considerably. If change ship type is allowed, the effect of grade difference becomes weaker and the cost can be controlled better.