Study On Multimodal Freight Transportation Service Network Topology For Express Shipment Based On Complex Network Theory

Transportation comes along with social economic development and evolves with the developing of the society and upgrading of industrial structure. Nowadays, there is an increasing demand for smaller quantities, faster, safer and just-in-time transport services. At the same time, economic growth contributes to the labor division and cooperation among different transportation modes and promotes continuous improvement of the comprehensive transportation system, which lays a solid foundation for the fast development of express freight service network. Rationality evolution model could be used to representation the mainly topology characteristics of express freight service network, and suggest temporal and spatial distribution of the new node. Furthermore, conclusions from evolution of express freight service network can not only support the decision-making in express freight programming, but also provide theory and method references for national express freight network planning and its sustainable developing.Based on complex network theory, this paper studied the characteristics and evolution mechanism of express freight service networks. First, three typical freight transportation service networks, which are railway, highway and airline, were studied separately, and then the characteristics of each network and network performances is analyzed, such as average path length, degree distribution, clustering coefficient and so on. Secondly, the characteristics of multimodal freight transportation service network for express shipment is studied. Taken a parcel transportation network that involved cooperation of railway and highway transportation as an example, this paper established the network model in space L and in space P separately, and analyzed the characteristics of each model. With the conclusions above, evolution mechanism of express freight service network was discussed, and an evolution model for express freight service network based on node attraction is established by considering the key factors of network accessibility and transportation demand. Next, taken geo-spatial constraints of the position of all nodes into account, the paper presented a new evolution model based on local-world. Finally, an example of multimode express freight transportation is presented to verify the modal and algorithm.