Network Traffic Simulation And Its Application In Navigation Strategy And Epidemic Spreading

With the development of social economy,the traffic demand is increasing.In urban road networks,traffic congestion occurs frequently,and transportation consumes lots of energy and causes serious emissions and pollution.In reality,different traffic networks are coupled with each other,and the traffic process is interwoven,such as the public transport network and subway network in the city,the aviation network,railway network and road network among cities.In such an integrated transportation system,once the epidemics break out,it may spread widely along with the transportation process.Therefore,it is of great importance to improve the efficiency of transportation,achieve energy conservation,and control the traffic-driven epidemic spreading.Based on microscopic simulation and macroscopic analysis,this paper explores the traffic flow and related characteristics of network system.The research can help understand the mechanism of these problems,and provide theoretical basis for traffic optimization control strategy.The main work of this thesis is as follows:1.Study the influence of amount of feedback information on urban traffic performance.Vehicles often face the problem of route selection in the road network.Effective information feedback strategy can help vehicles avoid congestion and improve traffic efficiency.However,the more feedback information collected and processed,the higher the economic cost.Interestingly,our simulation results show that more feedback information will not necessarily lead to better performance.Collecting the traffic information of first half road from upstream to downstream can get larger critical density and higher traffic flow than that collecting the information of the whole road.Through the distribution of vehicle density and the statistics of the proportion between turning vehicles and straight vehicles,we give a reasonable explanation for this phenomenon.2.Propose a dynamic route navigation strategy considering energy consumption,and compare the influence of different route navigation strategies on the performance of traffic system.With the rapid development of intelligent transportation system and connected vehicle technologies,the feedback of real-time energy consumption information of vehicles can be possible.Based on the real-time feedback of travel time and energy consumption,this paper proposes a cost minimization path navigation strategy.Compared with the geographic shortest path(without real-time information feedback),this strategy can significantly improve the traffic capacity.Compared with the time shortest path only based on real-time feedback of travel time,this strategy can save vehicle energy consumption and reduce travel cost.The superiority of the newly proposed strategy has been confirmed in different road network structures.In addition,combined with the pricing scheme,the strategy can further save energy of traffic system.3.Model the traffic-driven epidemic spreading in integrated transportation system based on multilayer network theory,and analyze the influence of multilayer network structure on the characteristics of epidemic spreading.The traffic process in a multimodal integrated transportation system is often accompanied by the spread of epidemics.For example,the infected passengers transfer between the bus and the subway,which makes the epidemic spread within the city.Road,railway and air transportation will drive the epidemic from one city(country)to another city(country).Based on the multilayer network theory,this paper establishes a traffic-driven epidemic spreading model.Through mean-field theoretical analysis and numerical simulation,it is found that:(1)when the difference in average path length between network layers is large,the epidemic spreading on the network layer with the smaller average degree will be completely suppressed by the multilayer structure;(2)with specific combination of network layer structure,the epidemic threshold of multiplayer structure will be larger.In other words,the multilayer structure can achieve the overall suppression of epidemic spreading.The reason for these phenomena is that compared with the isolated single-layer network,the traffic flow will be redistributed after forming the multiplex structure,which leads to the difference of the epidemic spreading in different network layers.The research results of this paper can be helpful in the design of vehicle route guidance system,in the optimization of traffic efficiency,in energy saving and emission reduction of transportation,and can provide traffic control schemes when epidemics break out.