中文摘要：

在快递企业的日常运营中，当两个城市之间的快递业务量达到一定规模之后会允许该城市对之间开展直达递送。但是这一规则通常仅在快递网络规划完成之后由相关子公司提请实施。为弥补这一实际规则的局部最优性缺陷，本论文将直达问题纳入网络规划决策，基于全局优化的视角构建了允许直达的混合轴幅式快递网络规划决策模型，设计了相应的求解流程，并对其中的指派关系决策构建了遗传算法。基于国内标杆企业的数值案例计算证明了该决策模型与求解方法的有效性，研究结果还说明，相对于纯轴辐式结构，允许直达的混合轴幅式网络结构有助于降低网络总成本，同时在直达线路上能够有效的降低迂回、提高服务时效性和服务水平。

英文摘要：

The research issue of this paper is from the practice of CPEL, China Postal Express and Logis- tics Company, the largest express company in China. It is found find that, in the network operation of ex- press business, the point-to-point direct shipment is permitted when the business volume is big enough. In order to make up the drawback in local optimum in operational rules, a hybrid hub-spoke express network decision-model permitting direct shipment is built on the basis of global optimum target, to answer the fol- lowing questions. 1） which nodes of the network should be chosen as hubs; 2） which nodes should each hub cover3） between which nodes should the point-to-point direct shipment exists. In this paper, it is appointed that, if the total business volume of forward logistics and reverse logistics between any pair ofor- igin-destination, then it can be believed that the express service demand between the two citie（origin anddestination） is frequent, and then, a point-to-point direct shipment is needed to replace the transshipment at the hub. In the model, the object is to minimize the total transport costs of the network, which include three parts： the first part is the transport costs between hub nodes and non-hub nodes, the second part is the transport costs between all hub nodes, and the third part is the transport costs on the directly connect- ed paths between non-hub nodes. The decision variables include binary variables Xk, which means node K is chosen as a hub when X=I, and a non-bub when Xk=O. Similarly, for binary variables Xij, ifX0 = 1, then node i is connected by node j, else, the two nodes are not connected. Here, we use binary varia- bles dis are used to judge whether non-hub nodes i and j should be directly connected： if the total business volume of forward logistics and reverse logistics between the two nodes is beyond a critical value Wo, then dij = 1, which means the two nodes should be directly connected, else, the two nodes should not be directly connected. The correspondin