Research On Key Node Selection And Station Layout Optimization Of Public Bicycles Based On Complex Network Theory

In recent years,with the rapid development of public bicycle system,its unique advantages of traffic flow dredging and its role in the daily life of residents have become increasingly prominent.At the same time,due to the surge of demand for use and the expansion of operation scale,the system gradually exposed many defects.For example,the vehicle turnover rate is not balanced between peak period and high frequency use place,the traffic flow distribution between central city and remote suburbs is uneven,the vehicle dispatching is difficult,and the cost is high.These problems are mainly caused by the unbalanced flow of some key nodes with large passenger flow.How to use scientific means to screen and optimize the control of these nodes is the key to improve the operation efficiency of public bicycle system.Complex networks are important tools for describing the interaction between systems and their constituent elements in the real world.In complex networks,there are many research methods on network structure stability,evolution law,traffic congestion dynamics and congestion guidance schemes that can be used for reference.Reasonable selection of key nodes and establishment of its shunt optimization scheme can better avoid network congestion and improve the operation efficiency of the whole system.Some data show that the existing optimization schemes of public bicycle system in China are mainly focused on single index screening problem nodes,and few consider traffic attributes and user travel characteristics.After selecting the key nodes,most of them have not given the next reasonable optimization plan.Based on the above facts and analysis,this paper uses real rental data of public bicycles to build a complex network.Aiming at the difficulties of optimization of dynamic topology and network layout in public bicycle transportation system,it evaluates the overall operation of the system,constructs the strategy of selecting key nodes,and achieves the overall optimization of the system by implementing dynamic optimization control on a small number of key nodes.The main research and results of this paper are as follows:1.Based on the actual operation data of public bicycle system,we make a statistical analysis of the network topology of public bicycle.The analysis results show that the network degree distribution conforms to the power law distribution,and the overall topological analysis shows that the user demand model of public bicycles has the characteristics of scale-free and small-world,which conforms to the "sixdimensional space theory".The integrated operation of the system is good,but a small number of key nodes in the network distribution can be further optimized.2?In order to solve the problem of dynamic stock imbalance of key nodes,According to the characteristics of public transportation of public bicycle system,associations are divided according to destination function area,and accessibility index potential evaluation model is designed to screen key nodes.3.Aiming at the selected key nodes,considering the location between the nodes,an optimization scheme of key nodes for public bicycles based on wave surface theory is proposed.The wave surface net flow threshold radiation method is used to place auxiliary nodes near key nodes to alleviate the pressure of key nodes in order to achieve local auxiliary shunting effect.Empirical results show that the strategy of selecting key nodes based on zonal accessibility index proposed in this paper can more fully reflect the characteristics of key nodes in each network.Wavefront theory network optimization scheme can effectively solve the imbalance of network nodes,optimize the layout of initial network points of public bicycles,improve vehicle utilization,and achieve the goal of improving overall efficiency from local optimization.It can provide useful guidance for the establishment of public bicycle system.