Accessibility is a representative indicator for evaluating the supply of bus system.Traditional studies have evaluated the accessibility from different aspects.Considering the interaction among land use,bus timetable ...Accessibility is a representative indicator for evaluating the supply of bus system.Traditional studies have evaluated the accessibility from different aspects.Considering the interaction among land use,bus timetable arrangement and individual factors,a more holistic accessibility measurement is proposed to combine static and dynamic characteristics from multisource traffic data.The rationale of the proposed model is verified by a case study of bus system in Shenzhen,China,which is carried out to find the spatial and temporal discrepancy of service of bus system.It is found that the adjustment of bus schedule to time-varying travel demand can affect accessibility of bus system and that Land-use development,average bus speed and bus facilities all have positive effects on accessibility of bus system.These findings provide sig-nificant reference for transport planning and policy-making.The proposed model is not limited to accessibility measuring of bus system,but also applicable to other travel modes.展开更多
Combination of a bus system and cable car system can reduce the overall congestion of traffic in urban areas, where surrounding hills or mountains hold larger settlements or tourist and recreational infrastructure. Wi...Combination of a bus system and cable car system can reduce the overall congestion of traffic in urban areas, where surrounding hills or mountains hold larger settlements or tourist and recreational infrastructure. With this kind of integration number of individual car trips can be significantly reduced. In this paper, the authors present an analysis of the pilot project implementation, which was held in Maribor. The authors conducted a limited test trial of two means of transportation, combining them into a single operating transport offer for inhabitants and tourists. Combined transport option proved to be a good starting point for reduction of traffic and parking congestion during winter tourist season and beyond. Method used in the research, in order to gain actual potential of integrating two systems and improving public transport offer, was establishment and implementation of the pilot project in Maribor during January 2011. Data was gathered through interviews of two interest groups. The first covered the users who were brought to the foothills of Pohorje＇s ski center by bus. The second covered the cable car users that were traveling to the top of Pohorje. For a limited time period, a trial principle of a single ticket was established, which gave ski-pass holders free bus ride on bus line No. 6. With the aim of reducing CO2, test drives of hybrid bus and compressed natural gas bus were conducted alongside many promotional activities with which users were informed of importance of environmentally friendly mobility options.展开更多
The school bus system in the United States took its form in 1939 when Frank W. Cyr, from the New York-based Teachers College of Columbia University, organized a national standards conference for school transportation....The school bus system in the United States took its form in 1939 when Frank W. Cyr, from the New York-based Teachers College of Columbia University, organized a national standards conference for school transportation. Representatives of education and transportation depart- ments from all 48 states, together with school bus manufacturers, attended the 7-day meeting. They worked out 45 standards and rules concerning school bus safety, specifying in detail school bus length, roof height, aisle width, etc.展开更多
The development,application,communication protocol and system structure of an airborne data bus system are discussed in this paper with emphasis on the design of hardware, software and optical fiber transmission syste...The development,application,communication protocol and system structure of an airborne data bus system are discussed in this paper with emphasis on the design of hardware, software and optical fiber transmission system of the bus controller and remote terminal. Some experiments and their results are also given in this paper.展开更多
In order to solve the complex wiring and low reliability of conventional light control system,an automobile contactless switch light system is designed combined with Hall element and controller area network （CAN） bu...In order to solve the complex wiring and low reliability of conventional light control system,an automobile contactless switch light system is designed combined with Hall element and controller area network （CAN） bus technology.The processing system of electromagnetic compatibility controlled by CAN bus is improved to reduce the electromagnetic interference from the controller and other sources of interference.With Freescale＇s high-performance single-chip MC9S08DZ60 and CAN transceiver TJA1050,the overall circuit design and software design are presented.The test results show that the designed light control system is feasible.展开更多
A power flow analysis method for weakly looped distribution systems with PV buses is proposed in this paper. The proposed method is computationally more efficient and more robust compared with the conventional compens...A power flow analysis method for weakly looped distribution systems with PV buses is proposed in this paper. The proposed method is computationally more efficient and more robust compared with the conventional compensation methods. The robustness is achieved by embedding the boundary conditions of loops and PV buses into the Jacobian matrix. The computational efficiency is achieved by the carefully designed factorization of Jacobian matrix. Test results on a 33 bus system are presented.展开更多
It is becoming increasingly difficult for Chinese citizens to access traditional public transport because of overcrowded community structures. Therefore, novel ideas are required to improve the transport system. In th...It is becoming increasingly difficult for Chinese citizens to access traditional public transport because of overcrowded community structures. Therefore, novel ideas are required to improve the transport system. In this respect, this study considers the design of a public transport scheduling model for a micro system. The model aims to minimize passenger waiting time and maximize number of passengers one bus carries, by simultaneously optimizing departure intervals and use of traditional and rapid buses. The model is superior to traditional models, as it analyzes the phenomena of vehicle overtaking, vehicle capacity limit, and passenger determination uncertainty. In addition, the model is a sophisticated nonlinear multi-objective optimization problem and contains more than one type of decision variable, therefore two composite algorithms, HPSO and GAPSO, are proposed, which are improvements of the Genetic Algorithm （GA） and Particle Swarm Optimization （PSO）. These two algorithms are compared to the classical GA with respect to stability and effect, and the results show them to be strong in both respects. In addition, the simultaneous optimization method has evident advantages compared to single-method optimizations.展开更多
A full distribution CNC system based on SERCOS bus is studied in accordance with the limitations of traditional PC-based motion card. The conventional PC-based motion control card is dispersed into several autonomous ...A full distribution CNC system based on SERCOS bus is studied in accordance with the limitations of traditional PC-based motion card. The conventional PC-based motion control card is dispersed into several autonomous intelligent servo-control units with the function of servo driver. The autonomous intelligent servocontrol units realize the loop control of position, velocity and current. Interpolation computation is completed in PC and the computational results are transferred to every autonomous intelligent servo-control unit by high speed SERCOS bus. Software or hardware synchronization technology is used to ensure all servomotors are successive and synchronously running. The communication and synchronization technology of SERCOS are also researched and the autonomous intelligent servo-control card is developed byself. Finally, the experiment of circle contour process on a prototype system proves the feasibility.展开更多
Operating short turning line is an efficient strategy to satisfy the unevenly distributed demand during peak periods while reducing operational cost.However,for the battery electric bus(BEB)system,the application of t...Operating short turning line is an efficient strategy to satisfy the unevenly distributed demand during peak periods while reducing operational cost.However,for the battery electric bus(BEB)system,the application of the strategy is challenging due to the disadvantages of BEBs,such as limited driving mileage and long charging time.Improper vehicle configuration and charging scheduling may dramatically increase the operational cost and cut the benefits of these strategies.In this work,we propose a general framework to design an effective short turning strategy for the BEB system at a tactical planning level.First,the trade-off relationship between the battery capacity and the average trip time is identified by modeling the BEBs operations.Second,a microeconomic model is formulated to jointly optimize the frequencies and charging schedules of the whole bus line and the short turning line,to effectively minimize passengers’waiting time and operational cost.Finally,numerical experiments have been carried out for an illustrative linear line to demonstrate the potential benefits of the sub-line operating strategy compared with the normal operation.展开更多
According to the construction of current coal mine monitoring and control systems in China, the paper proposes three kinds of applicable schemes of integrating PLC and DCS systems with field bus technology to digitize...According to the construction of current coal mine monitoring and control systems in China, the paper proposes three kinds of applicable schemes of integrating PLC and DCS systems with field bus technology to digitize the system and to improve the flexibility and extent of the system. Essentially, the paper introduces the integration of FCS on I/O layers. Based on a real coal mine safety-monitoring and control system applied with a CAN field bus, the major technology of system relays and extensions is discussed. We believe that one of the most applicable methods is currently replacing the connection between function-stations and field-sensors with a CAN bus on I/0 layers for system integration.展开更多
In this paper,a monitoring and controlling system for the safety in production and environmental parameters of a small and medium-sized coal mine has been developed after analyzing the current domestic coal production...In this paper,a monitoring and controlling system for the safety in production and environmental parameters of a small and medium-sized coal mine has been developed after analyzing the current domestic coal production and security conditions. The client computer can convert the analog signal about the safety in production and environmental parameters detected from the monitoring terminal into digital signal,and then,send the signal to the coal mine safety monitoring centre. This information can be analyzed,judged,and diagnosed by the monitoring-management-controlling software for helping the manager and technical workers to control the actual underground production and security situations. The system has many advantages including high reliability,better performance of real-time monitoring,faster data communicating and good practicability,and it can effectively prevent the occurrence of safety incidents in coal mines.展开更多
Compared with front engine vehicle, the windward side’s flow field in cooling model of rear engine bus is complicated and it can’t be calculated by means of 1D model. For this problem, this paper has used Star-CCM t...Compared with front engine vehicle, the windward side’s flow field in cooling model of rear engine bus is complicated and it can’t be calculated by means of 1D model. For this problem, this paper has used Star-CCM to build a 3D simulation model of cooling system, engine compartment and complete vehicle. Then, it had a 1D/3D coupling calculation on cooling system with Kuli software. It could be helpful in the optimization design of the flow field of rear engine compartment and optimization match of cooling system.展开更多
This paper investigates the impacts of a bus holding strategy on the mutual interference between buses and passenger cars in a non-dedicated bus route,as well as the impacts on the characteristics of pollutant emissio...This paper investigates the impacts of a bus holding strategy on the mutual interference between buses and passenger cars in a non-dedicated bus route,as well as the impacts on the characteristics of pollutant emissions of passenger cars.The dynamic behaviors of these two types of vehicles are described using cellular automata(CA)models under open boundary conditions.Numerical simulations are carried out to obtain the phase diagrams of the bus system and the trajectories of buses and passenger cars before and after the implementation of the bus holding strategy under different probabilities of passenger cars entering a two-lane mixed traffic system.Then,we analyze the flow rate,satisfaction rate,and pollutant emission rates of passenger cars together with the performance of a mixed traffic system.The results show that the bus holding strategy can effectively alleviate bus bunching,whereas it has no significant impact on the flow rate and pollutant emission rates of passenger cars;the flow rate,satisfaction rate,and pollutant emission rates of passenger cars for either the traffic system or for each lane are influenced by the bus departure interval and the number of passengers arriving at bus stops.展开更多
Bus bunching has been a persistent issue in urban bus system since it first appeared,and it remains a challenge not fully resolved.This phenomenon may reduce the operational efficiency of the urban bus system,which is...Bus bunching has been a persistent issue in urban bus system since it first appeared,and it remains a challenge not fully resolved.This phenomenon may reduce the operational efficiency of the urban bus system,which is detrimental to the operation of fast-paced public transport in cities.Fortunately,extensive research has been undertaken in the long development and optimization of the urban bus system,and many solutions have emerged so far.The purpose of this paper is to summarize the existing solutions and serve as a guide for subsequent research in this area.Upon careful examination of current findings,it is found that,based on the different optimization objects,existing solutions to the bus bunching problem can be divided into five directions,i.e.,operational strategy improvement,traffic control improvement,driver driving rules improvement,passenger habit improvement,and others.While numerous solutions to bus bunching are available,there remains a gap in research exploring the integrated application of methods from diverse directions.Furthermore,with the development of autonomous driving,it is expected that the use of modular autonomous vehicles could be the most potential solution to the issue of bus bunching in the future.展开更多
To guarantee bus priority with a minimum impact on car traffic at intersections, an optimal control system of the intermittent bus-only approach （IBA） was proposed. The problems of the existing system are first solv...To guarantee bus priority with a minimum impact on car traffic at intersections, an optimal control system of the intermittent bus-only approach （IBA） was proposed. The problems of the existing system are first solved through optimization： the judgment time of the IBA system was advanced to allow a bus to jump car queues if the bus was detected to arrive at the intersection, and the instant that the IBA lane became available to cars was controlled dynamically to increase the capacity of the IBA lane. The total car delay in one cycle was then analyzed quantitatively when implementing the optimal control system. The results show that in comparison with the existing system of the IBA, the car delay is greatly reduced and the probability of a car stopping twice is low after optimizing the IBA system.展开更多
A series-parallel system was proposed with common bus performance sharing in which the performance and failure rate of the element depended on the load it was carrying. In such a system,the surplus performance of a su...A series-parallel system was proposed with common bus performance sharing in which the performance and failure rate of the element depended on the load it was carrying. In such a system,the surplus performance of a sub-system can be transmitted to other deficient sub-systems. The transmission capacity of the common bus performance sharing mechanism is a random variable. Effects of load on element performance and failure rate were considered in this paper. A reliability evaluation algorithm based on the universal generating function technique was suggested. Numerical experiments were conducted to illustrate the algorithm.展开更多
This paper introduced the design of the hybrid powertrain of the Fuel Cell City Bus demonstrated in 2008 Beijing Olympic Games. The configuration of the hybrid fuel cell powertrain was introduced. The safety of hydrog...This paper introduced the design of the hybrid powertrain of the Fuel Cell City Bus demonstrated in 2008 Beijing Olympic Games. The configuration of the hybrid fuel cell powertrain was introduced. The safety of hydrogen storage and delivery system, the hydrogen leakage alarm system were developed. The real-time distributed control and diagnosis system based on the Time Trigger Controller Area Network （TTCAN） with 10 ms basic control period was developed. The concept and implementation of processor （or controller） monitor and process （or task） monitor technique based on the TYCAN were applied in this paper. The fault tolerant control algorithm of the fuel cell engine and the battery man- agement system were considered. The demonstration experience verified that the fault tolerant control was very important for the fuel cell city bus.展开更多
Purpose–The purpose of this paper is to develop a dynamic control method to improve bus schedule adherence under connected bus system.Design/methodology/approach–The authors developed a dynamic programming model tha...Purpose–The purpose of this paper is to develop a dynamic control method to improve bus schedule adherence under connected bus system.Design/methodology/approach–The authors developed a dynamic programming model that optimally schedules the bus operating speed at road sections and multiple signal timing plans at intersections to improve bus schedule adherence.First,the bus route was partitioned into three types of sections:stop,road and intersection.Then,transit agencies can control buses in real time based on all collected information;i.e.control bus operating speed on road sections and adjust the signal timing plans through signal controllers to improve the schedule adherence in connected bus environment.Finally,bus punctuality at the downstream stop and the saturation degree deviations of intersections were selected as the evaluation criteria in optimizing signal control plans and bus speeds jointly.Findings–An illustrative case study by using a bus rapid transit line in Jinan city was performed to verify the proposed model.It revealed that based on the proposed strategy,the objective value could be reduced by 73.7%,which indicated that the punctuality was highly improved but not to incur excessive congestion for other vehicular traffic.Originality/value–In this paper,the authors applied speed guidance and the adjustment of the signal control plans for multiple cycles in advance to improve the scheduled stability;furthermore,the proposed control strategy can reduce the effect on private traffics to the utmost extend.展开更多
Bus rapid transit (BRT) systems have been implemented in many cities over the past two decades. Widespread adoption of General Transit Feed Specification (GTFS), the deployment of high-fidelity bus GPS data tracking, ...Bus rapid transit (BRT) systems have been implemented in many cities over the past two decades. Widespread adoption of General Transit Feed Specification (GTFS), the deployment of high-fidelity bus GPS data tracking, and anonymized high-fidelity connected vehicle data from private vehicles have provided new opportunities for performance measures that can be used by both transit agencies and traffic signal system operators. This paper describes the use of trajectory-based data to develop performance measures for a BRT system in Indianapolis, Indiana. Over 3 million data records during the 3-month period between March and May 2022 are analyzed to develop visualizations and performance metrics. A methodology to estimate the average delay and schedule adherence is presented along a route comprised of 74 signals and 28 bus stations. Additionally, this research demonstrates how these performance measures can be used to evaluate dedicated and non-dedicated bus lanes with general traffic. Travel times and reliability of buses are compared with nearly 30 million private vehicle trips. Results show that median travel time for buses on dedicated bi-directional lanes is within one minute of general traffic and during peak periods the buses are often faster. Schedule adherence was observed to be more challenging, with approximately 3% of buses arriving within 1 minute on average during the 5AM hour and 5% of buses arriving 6 - 9 minutes late during the 5PM hour. The framework and performance measures presented in this research provide agencies and transportation professionals with tools to identify opportunities for adjustments and to justify investment decisions.展开更多
The paper study the software and hardware principles of ultrasonic ranging reversing radar, design the vehicle reversing radar based on intelligent node of CAN bus, realize data communication and resource sharing with...The paper study the software and hardware principles of ultrasonic ranging reversing radar, design the vehicle reversing radar based on intelligent node of CAN bus, realize data communication and resource sharing with other intelligent nodes of the reversing radar. The experimental results show that, the design can achieve the expected technical indicators design, measurement precision and the reliability is high, which has certain guiding significance in the design of the car reversing radar, has wide application prospect and practical significance in the function of the extended CAN bus communication messages design and automotive CAN network.展开更多
基金This work was jointly supported by the National Key Research and Development Program of China[grant num-ber 2018YFB1600900]the National Natural Science Foundation of China[grant number 71601045].
文摘Accessibility is a representative indicator for evaluating the supply of bus system.Traditional studies have evaluated the accessibility from different aspects.Considering the interaction among land use,bus timetable arrangement and individual factors,a more holistic accessibility measurement is proposed to combine static and dynamic characteristics from multisource traffic data.The rationale of the proposed model is verified by a case study of bus system in Shenzhen,China,which is carried out to find the spatial and temporal discrepancy of service of bus system.It is found that the adjustment of bus schedule to time-varying travel demand can affect accessibility of bus system and that Land-use development,average bus speed and bus facilities all have positive effects on accessibility of bus system.These findings provide sig-nificant reference for transport planning and policy-making.The proposed model is not limited to accessibility measuring of bus system,but also applicable to other travel modes.
文摘Combination of a bus system and cable car system can reduce the overall congestion of traffic in urban areas, where surrounding hills or mountains hold larger settlements or tourist and recreational infrastructure. With this kind of integration number of individual car trips can be significantly reduced. In this paper, the authors present an analysis of the pilot project implementation, which was held in Maribor. The authors conducted a limited test trial of two means of transportation, combining them into a single operating transport offer for inhabitants and tourists. Combined transport option proved to be a good starting point for reduction of traffic and parking congestion during winter tourist season and beyond. Method used in the research, in order to gain actual potential of integrating two systems and improving public transport offer, was establishment and implementation of the pilot project in Maribor during January 2011. Data was gathered through interviews of two interest groups. The first covered the users who were brought to the foothills of Pohorje＇s ski center by bus. The second covered the cable car users that were traveling to the top of Pohorje. For a limited time period, a trial principle of a single ticket was established, which gave ski-pass holders free bus ride on bus line No. 6. With the aim of reducing CO2, test drives of hybrid bus and compressed natural gas bus were conducted alongside many promotional activities with which users were informed of importance of environmentally friendly mobility options.
文摘The school bus system in the United States took its form in 1939 when Frank W. Cyr, from the New York-based Teachers College of Columbia University, organized a national standards conference for school transportation. Representatives of education and transportation depart- ments from all 48 states, together with school bus manufacturers, attended the 7-day meeting. They worked out 45 standards and rules concerning school bus safety, specifying in detail school bus length, roof height, aisle width, etc.
文摘The development,application,communication protocol and system structure of an airborne data bus system are discussed in this paper with emphasis on the design of hardware, software and optical fiber transmission system of the bus controller and remote terminal. Some experiments and their results are also given in this paper.
基金National Natural Science Foundation of China(No.61262007)Guizhou Science and Technology Department School Cooperation Project(Qian Bureau No.[2013]7001)Guiyang Science and Technology Department Platform for Innovation Plan(No.2012303)
文摘In order to solve the complex wiring and low reliability of conventional light control system,an automobile contactless switch light system is designed combined with Hall element and controller area network （CAN） bus technology.The processing system of electromagnetic compatibility controlled by CAN bus is improved to reduce the electromagnetic interference from the controller and other sources of interference.With Freescale＇s high-performance single-chip MC9S08DZ60 and CAN transceiver TJA1050,the overall circuit design and software design are presented.The test results show that the designed light control system is feasible.
文摘A power flow analysis method for weakly looped distribution systems with PV buses is proposed in this paper. The proposed method is computationally more efficient and more robust compared with the conventional compensation methods. The robustness is achieved by embedding the boundary conditions of loops and PV buses into the Jacobian matrix. The computational efficiency is achieved by the carefully designed factorization of Jacobian matrix. Test results on a 33 bus system are presented.
基金supported by the National Key Basic Research and Development Program in China(No.2016YFB0100906)the National Key Technology Research and Development Program(No.2014BAG03B01)+1 种基金the National Natural Science Foundation of China(Nos.61273238 and 61673232)Beijing Manicipal Science and Technology Program(No.D15110900280000)
文摘It is becoming increasingly difficult for Chinese citizens to access traditional public transport because of overcrowded community structures. Therefore, novel ideas are required to improve the transport system. In this respect, this study considers the design of a public transport scheduling model for a micro system. The model aims to minimize passenger waiting time and maximize number of passengers one bus carries, by simultaneously optimizing departure intervals and use of traditional and rapid buses. The model is superior to traditional models, as it analyzes the phenomena of vehicle overtaking, vehicle capacity limit, and passenger determination uncertainty. In addition, the model is a sophisticated nonlinear multi-objective optimization problem and contains more than one type of decision variable, therefore two composite algorithms, HPSO and GAPSO, are proposed, which are improvements of the Genetic Algorithm （GA） and Particle Swarm Optimization （PSO）. These two algorithms are compared to the classical GA with respect to stability and effect, and the results show them to be strong in both respects. In addition, the simultaneous optimization method has evident advantages compared to single-method optimizations.
文摘A full distribution CNC system based on SERCOS bus is studied in accordance with the limitations of traditional PC-based motion card. The conventional PC-based motion control card is dispersed into several autonomous intelligent servo-control units with the function of servo driver. The autonomous intelligent servocontrol units realize the loop control of position, velocity and current. Interpolation computation is completed in PC and the computational results are transferred to every autonomous intelligent servo-control unit by high speed SERCOS bus. Software or hardware synchronization technology is used to ensure all servomotors are successive and synchronously running. The communication and synchronization technology of SERCOS are also researched and the autonomous intelligent servo-control card is developed byself. Finally, the experiment of circle contour process on a prototype system proves the feasibility.
基金supported by the National Natural Science Foundation of China(71971018,71621001,72091513).
文摘Operating short turning line is an efficient strategy to satisfy the unevenly distributed demand during peak periods while reducing operational cost.However,for the battery electric bus(BEB)system,the application of the strategy is challenging due to the disadvantages of BEBs,such as limited driving mileage and long charging time.Improper vehicle configuration and charging scheduling may dramatically increase the operational cost and cut the benefits of these strategies.In this work,we propose a general framework to design an effective short turning strategy for the BEB system at a tactical planning level.First,the trade-off relationship between the battery capacity and the average trip time is identified by modeling the BEBs operations.Second,a microeconomic model is formulated to jointly optimize the frequencies and charging schedules of the whole bus line and the short turning line,to effectively minimize passengers’waiting time and operational cost.Finally,numerical experiments have been carried out for an illustrative linear line to demonstrate the potential benefits of the sub-line operating strategy compared with the normal operation.
文摘According to the construction of current coal mine monitoring and control systems in China, the paper proposes three kinds of applicable schemes of integrating PLC and DCS systems with field bus technology to digitize the system and to improve the flexibility and extent of the system. Essentially, the paper introduces the integration of FCS on I/O layers. Based on a real coal mine safety-monitoring and control system applied with a CAN field bus, the major technology of system relays and extensions is discussed. We believe that one of the most applicable methods is currently replacing the connection between function-stations and field-sensors with a CAN bus on I/0 layers for system integration.
基金supported by Technologies R&D of State Administration of Work Safety (06-399)Technologies R&D of Hunan Province ( No.05FJ4071)
文摘In this paper,a monitoring and controlling system for the safety in production and environmental parameters of a small and medium-sized coal mine has been developed after analyzing the current domestic coal production and security conditions. The client computer can convert the analog signal about the safety in production and environmental parameters detected from the monitoring terminal into digital signal,and then,send the signal to the coal mine safety monitoring centre. This information can be analyzed,judged,and diagnosed by the monitoring-management-controlling software for helping the manager and technical workers to control the actual underground production and security situations. The system has many advantages including high reliability,better performance of real-time monitoring,faster data communicating and good practicability,and it can effectively prevent the occurrence of safety incidents in coal mines.
文摘Compared with front engine vehicle, the windward side’s flow field in cooling model of rear engine bus is complicated and it can’t be calculated by means of 1D model. For this problem, this paper has used Star-CCM to build a 3D simulation model of cooling system, engine compartment and complete vehicle. Then, it had a 1D/3D coupling calculation on cooling system with Kuli software. It could be helpful in the optimization design of the flow field of rear engine compartment and optimization match of cooling system.
基金Project supported by the National Natural Science Foundation of China(Grant No.52172314)the Natural Science Foundation of Liaoning Province,China(Grant No.2022-MS-150)the Special Funding Project of Taishan Scholar Engineering.
文摘This paper investigates the impacts of a bus holding strategy on the mutual interference between buses and passenger cars in a non-dedicated bus route,as well as the impacts on the characteristics of pollutant emissions of passenger cars.The dynamic behaviors of these two types of vehicles are described using cellular automata(CA)models under open boundary conditions.Numerical simulations are carried out to obtain the phase diagrams of the bus system and the trajectories of buses and passenger cars before and after the implementation of the bus holding strategy under different probabilities of passenger cars entering a two-lane mixed traffic system.Then,we analyze the flow rate,satisfaction rate,and pollutant emission rates of passenger cars together with the performance of a mixed traffic system.The results show that the bus holding strategy can effectively alleviate bus bunching,whereas it has no significant impact on the flow rate and pollutant emission rates of passenger cars;the flow rate,satisfaction rate,and pollutant emission rates of passenger cars for either the traffic system or for each lane are influenced by the bus departure interval and the number of passengers arriving at bus stops.
基金sponsored by State Key Laboratory of Intelligent Green Vehicle and Mobility under Project No.KFY2421,China.
文摘Bus bunching has been a persistent issue in urban bus system since it first appeared,and it remains a challenge not fully resolved.This phenomenon may reduce the operational efficiency of the urban bus system,which is detrimental to the operation of fast-paced public transport in cities.Fortunately,extensive research has been undertaken in the long development and optimization of the urban bus system,and many solutions have emerged so far.The purpose of this paper is to summarize the existing solutions and serve as a guide for subsequent research in this area.Upon careful examination of current findings,it is found that,based on the different optimization objects,existing solutions to the bus bunching problem can be divided into five directions,i.e.,operational strategy improvement,traffic control improvement,driver driving rules improvement,passenger habit improvement,and others.While numerous solutions to bus bunching are available,there remains a gap in research exploring the integrated application of methods from diverse directions.Furthermore,with the development of autonomous driving,it is expected that the use of modular autonomous vehicles could be the most potential solution to the issue of bus bunching in the future.
文摘To guarantee bus priority with a minimum impact on car traffic at intersections, an optimal control system of the intermittent bus-only approach （IBA） was proposed. The problems of the existing system are first solved through optimization： the judgment time of the IBA system was advanced to allow a bus to jump car queues if the bus was detected to arrive at the intersection, and the instant that the IBA lane became available to cars was controlled dynamically to increase the capacity of the IBA lane. The total car delay in one cycle was then analyzed quantitatively when implementing the optimal control system. The results show that in comparison with the existing system of the IBA, the car delay is greatly reduced and the probability of a car stopping twice is low after optimizing the IBA system.
基金National Natural Science Foundations of China(Nos.71231001,11001005,71301009)China Postdoctoral Science Foundation(No.2013M530531)+1 种基金the Fundamental Research Funds for the Central Universities of China(Nos.FRF-M P-13-009A,FRF-TP-13-026A)the MOE PhD Supervisor Fund of China(No.20120006110025)
文摘A series-parallel system was proposed with common bus performance sharing in which the performance and failure rate of the element depended on the load it was carrying. In such a system,the surplus performance of a sub-system can be transmitted to other deficient sub-systems. The transmission capacity of the common bus performance sharing mechanism is a random variable. Effects of load on element performance and failure rate were considered in this paper. A reliability evaluation algorithm based on the universal generating function technique was suggested. Numerical experiments were conducted to illustrate the algorithm.
文摘This paper introduced the design of the hybrid powertrain of the Fuel Cell City Bus demonstrated in 2008 Beijing Olympic Games. The configuration of the hybrid fuel cell powertrain was introduced. The safety of hydrogen storage and delivery system, the hydrogen leakage alarm system were developed. The real-time distributed control and diagnosis system based on the Time Trigger Controller Area Network （TTCAN） with 10 ms basic control period was developed. The concept and implementation of processor （or controller） monitor and process （or task） monitor technique based on the TYCAN were applied in this paper. The fault tolerant control algorithm of the fuel cell engine and the battery man- agement system were considered. The demonstration experience verified that the fault tolerant control was very important for the fuel cell city bus.
基金supported by the National Natural Science Foundation of China(No.71771062)Natural Science Foundation of Zhejiang Province(LY18G030021)China Postdoctoral Science Foundation(NO.2019M661214).
文摘Purpose–The purpose of this paper is to develop a dynamic control method to improve bus schedule adherence under connected bus system.Design/methodology/approach–The authors developed a dynamic programming model that optimally schedules the bus operating speed at road sections and multiple signal timing plans at intersections to improve bus schedule adherence.First,the bus route was partitioned into three types of sections:stop,road and intersection.Then,transit agencies can control buses in real time based on all collected information;i.e.control bus operating speed on road sections and adjust the signal timing plans through signal controllers to improve the schedule adherence in connected bus environment.Finally,bus punctuality at the downstream stop and the saturation degree deviations of intersections were selected as the evaluation criteria in optimizing signal control plans and bus speeds jointly.Findings–An illustrative case study by using a bus rapid transit line in Jinan city was performed to verify the proposed model.It revealed that based on the proposed strategy,the objective value could be reduced by 73.7%,which indicated that the punctuality was highly improved but not to incur excessive congestion for other vehicular traffic.Originality/value–In this paper,the authors applied speed guidance and the adjustment of the signal control plans for multiple cycles in advance to improve the scheduled stability;furthermore,the proposed control strategy can reduce the effect on private traffics to the utmost extend.
文摘Bus rapid transit (BRT) systems have been implemented in many cities over the past two decades. Widespread adoption of General Transit Feed Specification (GTFS), the deployment of high-fidelity bus GPS data tracking, and anonymized high-fidelity connected vehicle data from private vehicles have provided new opportunities for performance measures that can be used by both transit agencies and traffic signal system operators. This paper describes the use of trajectory-based data to develop performance measures for a BRT system in Indianapolis, Indiana. Over 3 million data records during the 3-month period between March and May 2022 are analyzed to develop visualizations and performance metrics. A methodology to estimate the average delay and schedule adherence is presented along a route comprised of 74 signals and 28 bus stations. Additionally, this research demonstrates how these performance measures can be used to evaluate dedicated and non-dedicated bus lanes with general traffic. Travel times and reliability of buses are compared with nearly 30 million private vehicle trips. Results show that median travel time for buses on dedicated bi-directional lanes is within one minute of general traffic and during peak periods the buses are often faster. Schedule adherence was observed to be more challenging, with approximately 3% of buses arriving within 1 minute on average during the 5AM hour and 5% of buses arriving 6 - 9 minutes late during the 5PM hour. The framework and performance measures presented in this research provide agencies and transportation professionals with tools to identify opportunities for adjustments and to justify investment decisions.
文摘The paper study the software and hardware principles of ultrasonic ranging reversing radar, design the vehicle reversing radar based on intelligent node of CAN bus, realize data communication and resource sharing with other intelligent nodes of the reversing radar. The experimental results show that, the design can achieve the expected technical indicators design, measurement precision and the reliability is high, which has certain guiding significance in the design of the car reversing radar, has wide application prospect and practical significance in the function of the extended CAN bus communication messages design and automotive CAN network.
