In this paper, a modified averaging scheme is presented for a class of time-delayed vibration systems with slow variables. The new scheme is a combination of the averaging techniques proposed by Hale and by Lehman and...In this paper, a modified averaging scheme is presented for a class of time-delayed vibration systems with slow variables. The new scheme is a combination of the averaging techniques proposed by Hale and by Lehman and Weibel, respectively. The averaged equation obtained from the modified scheme is simple enough but it retains the required information for the local nonlinear dynamics around an equilibrium. As an application of the present method, the delay value for which a secondary Hopf bifurcation occurs is successfully located for a delayed van der Pol oscillator.展开更多
With the rapid development of urban road traffic and the increasing number of vehicles,how to alleviate traffic congestion is one of the hot issues that need to be urgently addressed in building smart cities.Therefore...With the rapid development of urban road traffic and the increasing number of vehicles,how to alleviate traffic congestion is one of the hot issues that need to be urgently addressed in building smart cities.Therefore,in this paper,a nonlinear multi-objective optimization model of urban intersection signal timing based on a Genetic Algorithm was constructed.Specifically,a typical urban intersection was selected as the research object,and drivers’acceleration habits were taken into account.What’s more,the shortest average delay time,the least average number of stops,and the maximum capacity of the intersection were regarded as the optimization objectives.The optimization results show that compared with the Webster method when the vehicle speed is 60 km/h and the acceleration is 2.5 m/s^(2),the signal intersection timing scheme based on the proposed Genetic Algorithm multi-objective optimization reduces the intersection signal cycle time by 14.6%,the average vehicle delay time by 12.9%,the capacity by 16.2%,and the average number of vehicles stop by 0.4%.To verify the simulation results,the authors imported the optimized timing scheme into the constructed Simulation of the Urban Mobility model.The experimental results show that the authors optimized timing scheme is superior to Webster’s in terms of vehicle average loss time reduction,carbon monoxide emission,particulate matter emission,and vehicle fuel consumption.The research in this paper provides a basis for Genetic algorithms in traffic signal control.展开更多
The sleep mode which works upon low arrival traffic is introduced in IEEE802.16e standard to reduce the power consumption of the mobile access terminal. Due to the rapid growth in the sleep interval in the exponential...The sleep mode which works upon low arrival traffic is introduced in IEEE802.16e standard to reduce the power consumption of the mobile access terminal. Due to the rapid growth in the sleep interval in the exponential growth algorithm prescribed in IEEE802.16e, the power saving efficiency of the mobile access terminal is limited and the average delay time of receiving data frames is prolonged when the arrival rate of data frames is low. To obtain lower power consumption and shorter average delay time, the l...展开更多
This study evaluated the operational performance of Transit Signal Priority(TSP)using a microscopic simulation approach.The analysis was based on a 10-mile study corridor in South Florida.Two microscopic VISSIM simula...This study evaluated the operational performance of Transit Signal Priority(TSP)using a microscopic simulation approach.The analysis was based on a 10-mile study corridor in South Florida.Two microscopic VISSIM simulation models were developed:a Base model,calibrated and validated to represent field conditions,and a TSP model.With TSP,the study corridor experienced up to 8%reduction in travel times and up to 13.3% reduction in average vehicle delay time,for both buses and all other vehicles.To better quantify the mobility benefits of the TSP strategy,Mobility Enhancement Factors(MEFs)were developed,unlike previous studies.A MEF is a multiplicative factor to estimate the expected mobility level after implementing TSP at a specific site.A MEF<1 implies that the TSP yields mobility benefits.TSP’s impact on cross-streets were also estimated.The study results indicate TSP strategy has enhanced mobility for buses and all other vehicles.展开更多
基金FANEDD of China (200430)the National Natural Science Foundation of China (10372116,10532050)
文摘In this paper, a modified averaging scheme is presented for a class of time-delayed vibration systems with slow variables. The new scheme is a combination of the averaging techniques proposed by Hale and by Lehman and Weibel, respectively. The averaged equation obtained from the modified scheme is simple enough but it retains the required information for the local nonlinear dynamics around an equilibrium. As an application of the present method, the delay value for which a secondary Hopf bifurcation occurs is successfully located for a delayed van der Pol oscillator.
基金supported by the joint NNSF&FDCT Project Number (0066/2019/AFJ)joint MOST&FDCT Project Number (0058/2019/AMJ),City University of Macao,Macao,China.
文摘With the rapid development of urban road traffic and the increasing number of vehicles,how to alleviate traffic congestion is one of the hot issues that need to be urgently addressed in building smart cities.Therefore,in this paper,a nonlinear multi-objective optimization model of urban intersection signal timing based on a Genetic Algorithm was constructed.Specifically,a typical urban intersection was selected as the research object,and drivers’acceleration habits were taken into account.What’s more,the shortest average delay time,the least average number of stops,and the maximum capacity of the intersection were regarded as the optimization objectives.The optimization results show that compared with the Webster method when the vehicle speed is 60 km/h and the acceleration is 2.5 m/s^(2),the signal intersection timing scheme based on the proposed Genetic Algorithm multi-objective optimization reduces the intersection signal cycle time by 14.6%,the average vehicle delay time by 12.9%,the capacity by 16.2%,and the average number of vehicles stop by 0.4%.To verify the simulation results,the authors imported the optimized timing scheme into the constructed Simulation of the Urban Mobility model.The experimental results show that the authors optimized timing scheme is superior to Webster’s in terms of vehicle average loss time reduction,carbon monoxide emission,particulate matter emission,and vehicle fuel consumption.The research in this paper provides a basis for Genetic algorithms in traffic signal control.
基金Supported by the Major National Science and Technology Special Project (No. 2010ZX03004-002)
文摘The sleep mode which works upon low arrival traffic is introduced in IEEE802.16e standard to reduce the power consumption of the mobile access terminal. Due to the rapid growth in the sleep interval in the exponential growth algorithm prescribed in IEEE802.16e, the power saving efficiency of the mobile access terminal is limited and the average delay time of receiving data frames is prolonged when the arrival rate of data frames is low. To obtain lower power consumption and shorter average delay time, the l...
基金sponsored by the Florida Department of Transportation(FDOT)and conducted as a cooperative effort by the Florida International University(FIU)and University of North Florida(UNF).
文摘This study evaluated the operational performance of Transit Signal Priority(TSP)using a microscopic simulation approach.The analysis was based on a 10-mile study corridor in South Florida.Two microscopic VISSIM simulation models were developed:a Base model,calibrated and validated to represent field conditions,and a TSP model.With TSP,the study corridor experienced up to 8%reduction in travel times and up to 13.3% reduction in average vehicle delay time,for both buses and all other vehicles.To better quantify the mobility benefits of the TSP strategy,Mobility Enhancement Factors(MEFs)were developed,unlike previous studies.A MEF is a multiplicative factor to estimate the expected mobility level after implementing TSP at a specific site.A MEF<1 implies that the TSP yields mobility benefits.TSP’s impact on cross-streets were also estimated.The study results indicate TSP strategy has enhanced mobility for buses and all other vehicles.
