蓄意攻击下全球集装箱海运网络脆弱性变化

为探究近年来全球集装箱海运网络脆弱性的变化趋势,提出了研究网络脆弱性变化度的分析思路和量化方法.基于2004和2014年两个年度的世界主要集装箱班轮公司航线分布数据,将相关港口按节点度大小排序后以1%~10%的比例逐步删除,选择删除前后的网络平均度,网络聚类系数,网络孤立节点比例,网络平均距离和网络效率等特征值的变化率作为量化指标;提出了网络压力测试方法,由此求出各特征值对网络脆弱性的影响权重及贡献值,进而得到了在设定攻击规模内集装箱海运网络脆弱性变化的量化值.研究结果表明:在蓄意攻击下,近10年的全球集装箱海运网络的脆弱性呈变差趋势;当攻击规模为整体网络的10%以内时,网络脆弱性的变差幅度约为6.1%.研究成果对于深化港口地理学研究具有重要意义,其分析思路和方法对其他领域的网络脆弱性变化趋势研究也可提供借鉴.

The change of global container shipping network vulnerability under intentional attack

To explore the current trend of the global container shipping network vulnerability, the analytical approach and quantitative methods were put forward for researching the change rate of the network vulnerability. We chose the routes distribution data from the world's main container liner companies in 2004 and 2014 as the study foundation. Sorted by the node degrees, the ports were gradually removed at a proportion from 1% to 10%. The quantitative foundation was the change rates of the eigenvalues before and after node removal, including the eigenvalues of network average degree, network clustering coefficient, network isolated-node proportion, network average shortest-path length and network efficiency. With the proposed pressure test, we calculated the weights and the values that each network eigenvalue has influence on the network vulnerability. Then we obtained the values of the change on the container shipping network vulnerability within the range of setting attack strength. The result shows that the vulnerability of the global container shipping network has the trend of becoming weaker in recent 10 years under intentional attack. When the scale of attack is less than 10% of the whole network, the vulnerability of the container shipping network has weakened by about 6.1%. The research conclusion in this paper has an important significance for deepening the research of port geography, and the analytical approach and method also provide reference to network characteristics analysis in other fields.