Evacuated Tube Transport Technologies （ET3） offers the potential for more than an order of magnitude improvement in transportation efficiency, speed, cost, and effectiveness. An ET3 network may be optimized to susta...Evacuated Tube Transport Technologies （ET3） offers the potential for more than an order of magnitude improvement in transportation efficiency, speed, cost, and effectiveness. An ET3 network may be optimized to sustainably displace most global transportation by car, ship, truck, train, and jet aircraft. To do this, ET3 standards should adhere to certain key principals： maximum value through efficiency, reliability, and simplicity; equal consideration for passenger and cargo loads; optimum size; high speed/high frequency operation; demand oriented; random accessibility; scalability; high granularity; automated control; full speed passive switching; open standards of implementation; and maximum use of existing capacities, materials, and processes.展开更多
In order to incorporate airworthiness requirements for flight characteristics into the entire development cycle of electronic flight control system（EFCS） equipped civil aircraft, digital virtual flight testing and e...In order to incorporate airworthiness requirements for flight characteristics into the entire development cycle of electronic flight control system（EFCS） equipped civil aircraft, digital virtual flight testing and evaluation method based on handling qualities rating method（HQRM）is proposed. First, according to HQRM, flight characteristics airworthiness requirements of civil aircraft in EFCS failure states are determined. On this basis, digital virtual flight testing model,comprising flight task digitized model, pilot controlling model, aircraft motion and atmospheric turbulence model, is used to simulate the realistic process of a pilot controlling an airplane to perform assigned flight tasks. According to the simulation results, flight characteristics airworthiness compliance of the airplane can be evaluated relying on the relevant regulations for handling qualities（HQ） rating. Finally, this method is applied to a type of passenger airplane in a typical EFCS failure state, and preliminary conclusions concerning airworthiness compliance are derived quickly. The research results of this manuscript can provide important theoretical reference for EFCS design and actual airworthiness compliance verification of civil aircraft.展开更多
1.A worldwide history of high-speed trains High-speed railway(HSR)is defined by the International Union of Railways(UIC)as new lines with design speeds above 250 kmh1 and upgraded existing lines with speeds of up to 2...1.A worldwide history of high-speed trains High-speed railway(HSR)is defined by the International Union of Railways(UIC)as new lines with design speeds above 250 kmh1 and upgraded existing lines with speeds of up to 200 kmh1[1].In China,HSR is defined as new passenger-dedicated lines designed for electric multiple unit(EMU)trains running at a speed of 250 kmh1 or above(actual or reserved),with an initial operation speed not lower than 200 kmh1[2].The worldwide development of HSRs and high-speed EMUs can be roughly divided into three stages:initial operation,line platform expansion,and rapid development.展开更多
The Newton Raphson iteration and QR algorithm are combined to search the Hpf bifurcation point of the vehicle running on straight track and on large radius curved tracks. Limit cycles that are bifurcated from the equ...The Newton Raphson iteration and QR algorithm are combined to search the Hpf bifurcation point of the vehicle running on straight track and on large radius curved tracks. Limit cycles that are bifurcated from the equilibrium points and the saddle node bifurcation point are computed through employing a variable step Runge Kutta method and the Poincaré map. Finally, numerical simulations are carried out for the stability of a high speed passenger car operating on straight and large radius curved tracks. The influences of the radius of curvature and the superelevation of the track on the stability of the vehicle system are investigated.展开更多
Metro passenger flow control problem is studied under given total inbound demand in this work,which considers passenger demand control and train capacity supply.Relevant connotations are analyzed and a mathematical mo...Metro passenger flow control problem is studied under given total inbound demand in this work,which considers passenger demand control and train capacity supply.Relevant connotations are analyzed and a mathematical model is developed.The decision variables are boarding limiting and stop-skipping strategies and the objective is the maximal passenger profit.And a passenger original station choice model based on utility theory is built to modify the inbound passenger distribution among stations.Algorithm of metro passenger flow control scheme is designed,where two key technologies of stopping-station choice and headway adjustment are given and boarding limiting and train stopping-station scheme are optimized.Finally,a real case of Beijing metro is taken for example to verify validity.The results show that in the three scenarios with different ratios of normal trains to stop-skipping trains,the total limited passenger volume is the smallest and the systematic profit is the largest in scenario 3.展开更多
In order to provide citizens with safe, convenient and comfortable services and infrastructure in a metropolis, the prediction of passenger flows in the metro-net of subway system has become more important than ever b...In order to provide citizens with safe, convenient and comfortable services and infrastructure in a metropolis, the prediction of passenger flows in the metro-net of subway system has become more important than ever before. Al- though a great number of prediction methods have been pre- sented in the field of transportation, all of them belong to the station oriented approach, which is not well suited to the Bei- jing subway system. This paper proposes a novel metro-net oriented method, called the probability tree based passenger flow model, which is also based on historic origin-destination （OD） information. First it learns and obtains the appearance probabilities for each kind of OD pair. For the real-time origin datum, the destination datum is calculated, and then several kinds of passenger flow in the metro-net can be pre- dicted by gathering all the contributions. The results of exper- iments, using the historical data of Beijing subway, show that although the proposed method has lower performance than existing prediction approaches for forecasting exit passenger flows, it is able to predict several additional kinds of passen- ger flow in stations and throughout the subway system; and it is a more feasible, suitable, and advanced passenger flow prediction model for Beijing subway system.展开更多
Lower limb injures are frequently observed in passenger car traffic accidents.Previous studies of the injuries focus on long bone fractures by using either cadaver component tests or simulations of the long bone kinem...Lower limb injures are frequently observed in passenger car traffic accidents.Previous studies of the injuries focus on long bone fractures by using either cadaver component tests or simulations of the long bone kinematics,which lack in-depth study on the fractures in stress analysis.This paper aims to investigate lower limb impact biomechanics in real-world car to pedestrian accidents and to predict fractures of long bones in term of stress parameter for femur,tibia,and fibula.For the above purposes,a 3D finite element(FE) model of human body lower limb(HBM-LL) is developed based on human anatomy.The model consists of the pelvis,femur,tibia,fibula,patella,foot bones,primary tendons,knee joint capsule,meniscus,and ligaments.The FE model is validated by comparing the results from a lateral impact between simulations and tests with cadaver lower limb specimens.Two real-world accidents are selected from an in-depth accident database with detailed information about the accident scene,car impact speed,damage to the car,and pedestrian injuries.Multi-body system(MBS) models are used to reconstruct the kinematics of the pedestrians in the two accidents and the impact conditions are calculated for initial impact velocity and orientations of the car and pedestrian during the collision.The FE model is used to perform injury reconstructions and predict the fractures by using physical parameters,such as von Mises stress of long bones.The calculated failure level of the long bones is correlated with the injury outcomes observed from the two accident cases.The reconstruction result shows that the HBM-LL FE model has acceptable biofidelity and can be applied to predict the risk of long bone fractures.This study provides an efficient methodology to investigate the long bone fracture suffered from vehicle traffic collisions.展开更多
Cities separated in space are connected together by spatial interaction (SI) between them. But the studies focusing on the SI are relatively few in China mainly because of the scarcity of data. This paper deals with t...Cities separated in space are connected together by spatial interaction (SI) between them. But the studies focusing on the SI are relatively few in China mainly because of the scarcity of data. This paper deals with the SI in terms of rail passenger flows, which is an important aspect of the network structure of urban agglomeration. By using a data set consisting of rail O-D (origin-destination) passenger flows among nearly 200 cities, intercity rail distance O-D matrixes, and some other indices, it is found that the attenuating tendency of rail passenger is obvious. And by the analysis on dominant flows and spatial structure of flows, we find that passenger flows have a trend of polarizing to hubs while the linkages between hubs upgrade. However, the gravity model reveals an overall picture of convergence process over time which is not in our expectation of integration process in the framework of globalization and economic integration. Some driven factors for the re-organization process of the structure of urban agglomeration, such as technique advance, globalization, etc. are discussed further based on the results we obtained.展开更多
文摘Evacuated Tube Transport Technologies （ET3） offers the potential for more than an order of magnitude improvement in transportation efficiency, speed, cost, and effectiveness. An ET3 network may be optimized to sustainably displace most global transportation by car, ship, truck, train, and jet aircraft. To do this, ET3 standards should adhere to certain key principals： maximum value through efficiency, reliability, and simplicity; equal consideration for passenger and cargo loads; optimum size; high speed/high frequency operation; demand oriented; random accessibility; scalability; high granularity; automated control; full speed passive switching; open standards of implementation; and maximum use of existing capacities, materials, and processes.
基金supported by the National High-tech Research and Development Program of China(No.2014AA110500)
文摘In order to incorporate airworthiness requirements for flight characteristics into the entire development cycle of electronic flight control system（EFCS） equipped civil aircraft, digital virtual flight testing and evaluation method based on handling qualities rating method（HQRM）is proposed. First, according to HQRM, flight characteristics airworthiness requirements of civil aircraft in EFCS failure states are determined. On this basis, digital virtual flight testing model,comprising flight task digitized model, pilot controlling model, aircraft motion and atmospheric turbulence model, is used to simulate the realistic process of a pilot controlling an airplane to perform assigned flight tasks. According to the simulation results, flight characteristics airworthiness compliance of the airplane can be evaluated relying on the relevant regulations for handling qualities（HQ） rating. Finally, this method is applied to a type of passenger airplane in a typical EFCS failure state, and preliminary conclusions concerning airworthiness compliance are derived quickly. The research results of this manuscript can provide important theoretical reference for EFCS design and actual airworthiness compliance verification of civil aircraft.
文摘1.A worldwide history of high-speed trains High-speed railway(HSR)is defined by the International Union of Railways(UIC)as new lines with design speeds above 250 kmh1 and upgraded existing lines with speeds of up to 200 kmh1[1].In China,HSR is defined as new passenger-dedicated lines designed for electric multiple unit(EMU)trains running at a speed of 250 kmh1 or above(actual or reserved),with an initial operation speed not lower than 200 kmh1[2].The worldwide development of HSRs and high-speed EMUs can be roughly divided into three stages:initial operation,line platform expansion,and rapid development.
文摘The Newton Raphson iteration and QR algorithm are combined to search the Hpf bifurcation point of the vehicle running on straight track and on large radius curved tracks. Limit cycles that are bifurcated from the equilibrium points and the saddle node bifurcation point are computed through employing a variable step Runge Kutta method and the Poincaré map. Finally, numerical simulations are carried out for the stability of a high speed passenger car operating on straight and large radius curved tracks. The influences of the radius of curvature and the superelevation of the track on the stability of the vehicle system are investigated.
基金Projects(RCS2015ZZ002,RCS2014ZT25)supported by State Key Laboratory of Rail Traffic Control&Safety,ChinaProject(2015RC058)supported by Beijing Jiaotong University,China
文摘Metro passenger flow control problem is studied under given total inbound demand in this work,which considers passenger demand control and train capacity supply.Relevant connotations are analyzed and a mathematical model is developed.The decision variables are boarding limiting and stop-skipping strategies and the objective is the maximal passenger profit.And a passenger original station choice model based on utility theory is built to modify the inbound passenger distribution among stations.Algorithm of metro passenger flow control scheme is designed,where two key technologies of stopping-station choice and headway adjustment are given and boarding limiting and train stopping-station scheme are optimized.Finally,a real case of Beijing metro is taken for example to verify validity.The results show that in the three scenarios with different ratios of normal trains to stop-skipping trains,the total limited passenger volume is the smallest and the systematic profit is the largest in scenario 3.
基金This work was supported by the National High- Tech Research and Development Plan of China （863） （2011AA010502）, the National Natural Science Foundation of China （Grant No. 61103093）, the Doctoral Fund of Ministry of Education of China （20091102110017）, the International Science ＆ Technology Cooperation Program of China （2010DFB 13350）, the Supported Project （SKLSDE-2012ZX-16） of the State Key Laboratory of Software Development Environment, and the Fundamen- tal Research Funds for the Central Universities. We are thankful to Bei- jing Municipal Committee of Transportation, Beijing Metro Network Con- trol Center, Beijing Mass Transit Railway Operation Corporation Limited, and Beijing MTR Corporation for their great help.
文摘In order to provide citizens with safe, convenient and comfortable services and infrastructure in a metropolis, the prediction of passenger flows in the metro-net of subway system has become more important than ever before. Al- though a great number of prediction methods have been pre- sented in the field of transportation, all of them belong to the station oriented approach, which is not well suited to the Bei- jing subway system. This paper proposes a novel metro-net oriented method, called the probability tree based passenger flow model, which is also based on historic origin-destination （OD） information. First it learns and obtains the appearance probabilities for each kind of OD pair. For the real-time origin datum, the destination datum is calculated, and then several kinds of passenger flow in the metro-net can be pre- dicted by gathering all the contributions. The results of exper- iments, using the historical data of Beijing subway, show that although the proposed method has lower performance than existing prediction approaches for forecasting exit passenger flows, it is able to predict several additional kinds of passen- ger flow in stations and throughout the subway system; and it is a more feasible, suitable, and advanced passenger flow prediction model for Beijing subway system.
基金supported by National Hi-tech Research and Development Program of China (863 Program,Grant No. 2006AA110101)"111 Program" of Ministry of Education and State Administration of Foreign Experts Affairs of China (Grant No. 111-2-11)+1 种基金General Motors Research and Development Center (Grant No. RD-209)Project of State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body,Hunan University,China (Grant No. 60870004)
文摘Lower limb injures are frequently observed in passenger car traffic accidents.Previous studies of the injuries focus on long bone fractures by using either cadaver component tests or simulations of the long bone kinematics,which lack in-depth study on the fractures in stress analysis.This paper aims to investigate lower limb impact biomechanics in real-world car to pedestrian accidents and to predict fractures of long bones in term of stress parameter for femur,tibia,and fibula.For the above purposes,a 3D finite element(FE) model of human body lower limb(HBM-LL) is developed based on human anatomy.The model consists of the pelvis,femur,tibia,fibula,patella,foot bones,primary tendons,knee joint capsule,meniscus,and ligaments.The FE model is validated by comparing the results from a lateral impact between simulations and tests with cadaver lower limb specimens.Two real-world accidents are selected from an in-depth accident database with detailed information about the accident scene,car impact speed,damage to the car,and pedestrian injuries.Multi-body system(MBS) models are used to reconstruct the kinematics of the pedestrians in the two accidents and the impact conditions are calculated for initial impact velocity and orientations of the car and pedestrian during the collision.The FE model is used to perform injury reconstructions and predict the fractures by using physical parameters,such as von Mises stress of long bones.The calculated failure level of the long bones is correlated with the injury outcomes observed from the two accident cases.The reconstruction result shows that the HBM-LL FE model has acceptable biofidelity and can be applied to predict the risk of long bone fractures.This study provides an efficient methodology to investigate the long bone fracture suffered from vehicle traffic collisions.
基金Under the auspices of Key Project of National Natural Science Foundation of China (No 40635026)
文摘Cities separated in space are connected together by spatial interaction (SI) between them. But the studies focusing on the SI are relatively few in China mainly because of the scarcity of data. This paper deals with the SI in terms of rail passenger flows, which is an important aspect of the network structure of urban agglomeration. By using a data set consisting of rail O-D (origin-destination) passenger flows among nearly 200 cities, intercity rail distance O-D matrixes, and some other indices, it is found that the attenuating tendency of rail passenger is obvious. And by the analysis on dominant flows and spatial structure of flows, we find that passenger flows have a trend of polarizing to hubs while the linkages between hubs upgrade. However, the gravity model reveals an overall picture of convergence process over time which is not in our expectation of integration process in the framework of globalization and economic integration. Some driven factors for the re-organization process of the structure of urban agglomeration, such as technique advance, globalization, etc. are discussed further based on the results we obtained.
