Vulnerability Evolution And Simulation Of Container Shipping Networks Under Contingencies

Maritime transport is the most important mode of transport in international trade,accounting for more than two-thirds of the total international trade volume,and the container shipping network is an important reliance on global economic trade.However,contingencies such as severe weather,public health events and social security events can damage the spatial structure and transport functions of container shipping networks and negatively affect the operational reliability of container shipping networks.Considering the uncertainty,complexity and destructiveness of unexpected events,clarifying the influence path of dynamic evolution of unexpected events on the cascade failure of container shipping network is the key to guarantee the safe operation and high quality operation of container shipping network.In this regard,this paper constructs a two-layer coupled container network,portrays the impact transmission mechanism of unexpected events on the container shipping network,designs diverse scenarios according to the risk level of unexpected events,and evaluates the vulnerability of the container shipping network under different scenarios.(1)Double-layer coupled container shipping network portrayal.The two-layer coupled container network is constructed based on complex network theory,including maritime subnetwork and consolidation sub-network,taking into full consideration the whole process operation of container transportation.The individual characteristics of nodes and the overall structural characteristics of the double-layer coupled container shipping network are analysed from the metrics of degree distribution,clustering coefficient,average path length and so on.(2)Construction of cascade failure model of container shipping network considering risk level.Based on the load capacity model and the contagion model,the load redistribution method of the failed nodes of the container shipping network is proposed.The risk level of contingencies is further considered,and on this basis three attack modes are specified,and the assessment index of network cascade failure vulnerability is selected as the basis for assessing the importance of nodes.A simulation process of a double-layer coupled container shipping network is designed to simulate the process of cascade failure of the container shipping network,analyse the dynamic evolution of contingencies on the cascade failure path of the container shipping network,and further assess the vulnerability of the container shipping network in terms of quantity,propagation,extent and efficiency.(3)An empirical study is conducted on the container shipping network in China and the United States as an example.By constructing the China-US container shipping network model,the characteristic parameters of the China-US container shipping network are calculated and analysed.The validity of the model is verified through practical cases,and the cascading failure process of the Sino-US container shipping network under three types of attacks is simulated,and suggestions for effective improvement of the vulnerability of the container shipping network are made for each type of contingency.Through the analysis of the factors influencing the vulnerability of container shipping network,this thesis reveals the mechanism of action on the risk propagation probability of the vulnerability of container shipping network,which provides a decision basis for the management department to prevent the occurrence of operation accidents to reduce the vulnerability of container shipping network and has important reference significance to ensure the smooth operation of container shipping network.