基于运达时间可靠性的快捷货运服务网络运输能力计算

Calculation of Capacity of the Express Freight Transportation Service Network under Constraint of Delivery Time

鉴于快捷货运网络中存在多种运输方式、对货物运达服务要求高等特点,提出以运达时间可靠性为主要约束的快捷货运服务网络运输能力计算方法,设计遗传操作与蒙特卡洛模拟相结合的混合智能算法。对既有文献的算例进行结果分析后得出:当快捷货运需求较低时,快捷货运服务网络可以在要求的运达时间限制条件下完成相应的运输任务;当快捷货运需求很高时,快捷货运服务网络运输能力的可靠性急剧下降,即当拥挤时,快捷货运服务网络运达时间可靠性很难得到保证。

In view of the characteristics of the express freight transportation network such as multi-mode operations and high requirements for delivery service, the method for determining the capacity of the express freight transportation service network was put forward under constraint of reliability of the delivery time. The hybrid intelligent algorithm was designed, which integrated the genetic operation and Monte Carlo simulation. Referring to the existing relevant literature, results of a numerical case show as follows. When the demand level ok express freight transportation is low, the express freight transportation service network is able to finish all freight assignments at the required delivery time; when the express freight transportation demand reaches a very high level, the reliability of the express freight transportation service network decreases dramatically, i. e. , in the case of congestion, the reliability of on-time delivery is hard to be guaranteed.