城市公交网络级联失效分析

Cascading failure analysis of urban public transit network

为提高城市公交网络(Urban Public Transit Network,UPTN)的抗毁性,基于复杂网络理论系统性研究了UPTN级联失效。以厦门市公交网络为例,利用改进的Space-L方法构建UPTN,设定网络效率、网络最大连通率和故障站点比率作为网络抗毁性的度量指标,基于非线性负荷-容量的UPTN级联失效模型研究了网络在级联失效下的抗毁性,并对比无级联失效下的网络抗毁性。结果表明:容量参数α的减少或β的增加,对网络抗毁性有着显著的提升;当β处于临界阈值时,小幅增加β,网络抗毁性呈现出突增现象;当α=0.2、β=0.7时,网络具有较强的抗毁性,网络在级联失效下可抵挡283次蓄意攻击、575次随机攻击;有、无级联失效下,网络均对蓄意攻击具有脆弱性,对随机攻击具有稳定性,而考虑级联失效情况下的网络,其脆弱性更为明显。

In order to improve the invulnerability of urban public transit network(UPTN),the cascading failure of UPTN is systematically studied based on complex network theory.Taking the public transit network in Xiamen as an example,the improved Space-L method is used to construct UPTN,and the network efficiency,the maximum network connectivity rate and the ratio of faulty stations are set as the metrics of the invulnerability of network.The cascading failure model of UPTN based on nonlinear load-capacity utilized to study the invulnerability of network under cascading failure,and to compare the invulnerability of network without cascading failure.The results show that the reduction of the capacity parameterαor the increase ofβcan significantly enhance the invulnerability of network;Whenβapproaches its critical threshold andβexperiences a slight increase,the invulnerability of the network shows a sudden increase;Whenα=0.2 andβ=0.7,the network displays substantial invulnerability,enduring 283 deliberate attacks and 575 random attacks during cascading failure;With or without cascading failure,the network is vulnerable to deliberate attacks and robust to random attacks,and the network is more vulnerable under cascading failure.