城市公交网络的拓扑结构特性源于其内在的演化生成机制。以国内4个城市公交网络为研究对象,分别在L空间和P空间对这些网络的度分布、集聚系数和平均路径长度进行了计算和分析。研究发现,公交网络中经过站点的线路数分布服从幂律分布,节点的度分布服从指数分布。基于此,提出了公交网络的演化生成机制——线路择优连接和站点随机游走机制,并构建了公交网络的演化模型。数值仿真结果表明,模型反映了公交网络演化生成过程的关键要素。
The topological property of urban transit network rises from its intrinsic evolutional growth mechanism. Taken four domestic transit networks as objects, the degree distribution, clustering coefficient and average path length of these networks in space L and P were calculated and analyzed respectively. It is found that in transit networks the distribution of number of transit line that passes stations is power distribution and the degree distribution of nodes obeys exponential distribution. Based on this, the evolutional growth mechanism of transit network-preferential attachment of lines and mechanism of random walk of stations were proposed, and an evolutional model of transit network was established. Numerical simulation results show that the model reflects the key elements in the evolution of transit network.