Akbarzadeh Meisam, Memarmontazerin Soroush, Soleimani Sheida
1Department of Transportation Engineering, Isfahan University of Technology, Isfahan, Iran.
2Department of Civil Engineering, University of Isfahan, Isfahan, Iran.
Appl Netw Sci. 2018;3(1):4. doi: 10.1007/s41109-018-0060-9. Epub 2018 Apr 4.
Spatial embeddedness and planarity of urban road networks limit the range of their node degree values. Therefore, pursuing analysis based on the distribution of node degrees e.g. scale free aspect could not be accomplished in urban road networks. We have inspected the distribution of degree, betweenness centrality, weighted degree (based on incident link capacities), and alpha weighted degree for eight urban road networks across the world. These networks are abstracted from Philadelphia (USA), Berlin (Germany), Chicago (USA), Anaheim (USA), Gold Coast (Australia), Birmingham (UK), and Isfahan (Iran). Our results show that although the degree (weighted and unweighted) distributions of these networks are totally different, they all show power law distributions in betweenness centrality. Thus, scale free aspect could be observed in the betweenness centrality distribution. We then analyzed the collapse of network as a result of node removals. The collapse patterns suggest that critical nodes of urban road networks could not be detected solely based on betweenness centrality. Therefore, we conclude that the concept of betweenness centrality in urban road networks is more of functional merit than topological merit. In other words, central nodes play an important role in transmitting the flow but their loss would not harm the connectivity of urban networks. This claim is supported by analyzing the correlation among node flow and node betweenness in Isfahan and Anaheim.
城市道路网络的空间嵌入性和平面性限制了其节点度值的范围。因此，在城市道路网络中无法进行基于节点度分布（如无标度特征）的分析。我们考察了全球八个城市道路网络的度分布、中介中心性、加权度（基于关联链路容量）和α加权度。这些网络分别取自美国费城、德国柏林、美国芝加哥、美国阿纳海姆、澳大利亚黄金海岸、英国伯明翰和伊朗伊斯法罕。我们的结果表明，尽管这些网络的度（加权和未加权）分布完全不同，但它们在中介中心性上均呈现幂律分布。因此，在中介中心性分布中可以观察到无标度特征。然后我们分析了由于节点移除导致的网络崩溃情况。崩溃模式表明，不能仅基于中介中心性来检测城市道路网络的关键节点。因此，我们得出结论，城市道路网络中的中介中心性概念更多地是功能优势而非拓扑优势。换句话说，中心节点在流量传输中起着重要作用，但它们的缺失不会损害城市网络的连通性。对伊斯法罕和阿纳海姆的节点流量与节点中介中心性之间相关性的分析支持了这一观点。
