混合式航空货运网络优化

为了优化具有点-点式与轴-辐式混合特征的航空货运网络, 基于航空货运企业的OD流量, 构建了双层优化模型。上层模型以货运企业总运输成本最小为目标, 优化航空货运网络结构与配置运力, 下层模型计算均衡状态下各航段上的货物流量。选取顺丰航空服务的14个城市的相关数据对双层优化模型进行验证, 以设置4个枢纽机场为前提, 分别对使用4、5、6架全货机的货运情况进行分析。分析结果表明: 3种情况下北京、上海、南京、深圳4个机场均被设置为枢纽机场; 当使用4架全货机时, 全货机分别被安排在北京-南京、北京-深圳、上海-深圳、南京-深圳的航段上, 4个枢纽机场的快件中转率分别为24.3%、24.2%、47.8%、14.9%, 南京机场的快件中转率最大, 深圳机场最小; 当使用5架全货机时, 第5架全货机被安排在北京-上海航段上, 其余4架全货机的航段没有变化, 4个枢纽机场的快件中转率分别为38.6%、50.9%、44.3%、11.9%, 上海机场的快件中转率最大, 深圳机场最小; 当使用6架全货机时, 各枢纽机场间的航段上都有全货机, 4个枢纽机场的快件中转率分别为38.5%、74.0%、79.5%、10.2%, 南京机场的最大, 深圳机场的最小。可见, 南京是典型的中转型枢纽城市, 而深圳是典型的腹地型枢纽城市; 货运需求大的城市的机场易被确定为枢纽机场; 枢纽机场与非枢纽机场都可能中转货物; 距离较近的2个机场可能会同时被确定为枢纽机场。

Optimzation of mixed air cargo transportation network

In order to optimize the air cargo transportation network with the mixed characteristics of point-to-point and hub-and-spoke, a bi-level optimization model was built based on the OD flow of air cargo transportation companies.The objective of upper model was designed to minimize the total transportation cost, and the air cargo transportation network structure and the configuration capacity were optimized.The equilibrium cargo flow on each link was calculated in the lower model.The bi-level optimization model was verified by using the related data of fourteen cities served by Shunfeng Airlines, under the premise of setting 4 hub airports, the cases with 4-6 cargo aircrafts were analyzed respectively.Analysis result indicates that in the three cases, four airports of Beijing, Shanghai, Nanjing and Shenzhen are all set as hub airports.When 4 cargoaircrafts are used, the cargo aircrafts are arranged on the flight segments of Beijing-Nanjing, Beijing-Shenzhen, Shanghai-Shenzhen and Nanjing-Shenzhen respectively.The transshipping ratios of 4 hub airports are 24.3%, 24.2%, 47.8% and 14.9% respectively, and the transshipping ratio of Nanjing Airport is the largest, while the ratio of Shenzhen Airport is the smallest.When 5 cargo aircrafts are used, the fifth cargo aircraft is arranged on the flight segment of Beijing-Shanghai, the flight segments of the other 4 cargo aircrafts remain unchanged.The transshipping ratios of 4 hub airports are 38.6%, 50.9%, 44.3% and 11.9% respectively, and the transshipping ratio of Shanghai Airport is the largest, while the ratio of Shenzhen Airport is the smallest.When 6 cargo aircrafts are used, all flight segments between hub airports are arranged with cargo aircrafts.The transshipping ratios of 4 hub airports are 38.5%, 74.0%, 79.5% and 10.2% respectively, and the transshipping ratio of Nanjing Airport is the largest, while the ratio of Shenzhen Airport is the smallest.Therefore Nanjing is a typical transshipping hub city, and Shenzhen is a typical hinterland hub city.The airports in the cities with large transport demand are determined to be hubs easily.Both hub airports and non-hub airports may transship cargos.Two nearby airports may be determined as hub airports simultaneously.