Static strength finite element analysis was conducted to decrease the weight of a skeleton vehicle's frame. Results indicated that the maximum stress occurs on the front beam 's variable section area. Dynamic sensit...Static strength finite element analysis was conducted to decrease the weight of a skeleton vehicle's frame. Results indicated that the maximum stress occurs on the front beam 's variable section area. Dynamic sensitivity analysis elucidated the relationship between the maximum stress and the thickness of a particular beam,e. g.,top,middle,and bottom beam. Displacement was analyzed by the key part that influenced the maximum stress. Finally,the new plan using BS960 super-high-strength beam steel and the preferred beam thickness was compared with the original plan. New combinations of beam thickness were introduced on the basis of different purposes; the maximum responding light w eight ratio was 21%.展开更多
Security systems are a necessity for the deployment of smart vehicles in our society. Security in vehicular ad hoe networks is crucial to the reliable exchange of information and control data. In this paper, we propos...Security systems are a necessity for the deployment of smart vehicles in our society. Security in vehicular ad hoe networks is crucial to the reliable exchange of information and control data. In this paper, we propose an intelligent Intrusion Detection System (IDS) to protect the external communication of self-driving and semi self-driving vehicles. This technology has the ability to detect Denial of Service (DOS) and black hole attacks on vehicular ad hoe networks (VANETs). The advantage of the proposed IDS over existing security systems is that it detects attacks before they causes significant damage. The intrusion prediction technique is based on Linear Discriminant Analysis (LDA) and Quadratic Diseriminant Analysis (QDA) which are used to predict attacks based on observed vehicle behavior. We perform simulations using Network Simulator 2 to demonstrate that the IDS achieves a low rate of false alarms and high accuracy in detection.展开更多
The fexibility of a train's wheelset can have a large effect on vehicle–track dynamic responses in the medium to high frequency range.To investigate the effects of wheelset bending and axial deformation of the wheel...The fexibility of a train's wheelset can have a large effect on vehicle–track dynamic responses in the medium to high frequency range.To investigate the effects of wheelset bending and axial deformation of the wheel web,a specifi coupling of wheel–rail contact with a fexible wheelset is presented and integrated into a conventional vehicle–track dynamic system model.Both conventional and the proposed dynamic system models are used to carry out numerical analyses on the effects of wheelset bending and axial deformation of the wheel web on wheel–rail rolling contact behaviors.Excitations with various irregularities and speeds were considered.The irregularities included measured track irregularity and harmonic irregularities with two different wavelengths.The speeds ranged from 200 to400km/h.The results show that the proposed model can characterize the effects of fexible wheelset deformation on the wheel–rail rolling contact behavior very well.展开更多
Static stability analysis of the two-point mooring autonomous underwater vehicle(AUV) is presented.The mathematic model is a set of equilibrium equations describing the attitude of the AUV.The mooring lines are regard...Static stability analysis of the two-point mooring autonomous underwater vehicle(AUV) is presented.The mathematic model is a set of equilibrium equations describing the attitude of the AUV.The mooring lines are regarded as inelastic catenaries,and five degrees of freedom of AUV are considered.The stability of the system is represented by inequality conditions between several physical quantities and the corresponding limitations.We analyze stability of the prime AUV and find that the AUV has a flow-following tendency,which makes the swing angle big.The result shows that the two-point mooring AUV can remain stable under 2.5 kn ocean current speed,and it will weigh anchor when the speed is greater than 3 kn.Subsequent parametric study reveals the influence of the designing parameters on the stability.展开更多
1.The overall development of new energy vehicles was good in 2017.In early 2017,the new energy vehicle market was greatly affected by major policy adjustments such as drastic decline in new energy vehicle subsidies an...1.The overall development of new energy vehicles was good in 2017.In early 2017,the new energy vehicle market was greatly affected by major policy adjustments such as drastic decline in new energy vehicle subsidies and re-examination of the model catalogue.But China’s determination to vigorously promote the healthy development of the new energy vehicle industry has not changed.In March and April。展开更多
As a strategic emerging industry,the new energy vehicle industry has been a key industry in China in recent years and has great significance for China to realize industrial transformation and upgrading,and seize the c...As a strategic emerging industry,the new energy vehicle industry has been a key industry in China in recent years and has great significance for China to realize industrial transformation and upgrading,and seize the commanding heights of international competition.In particular,the industry has been vigorously boosted by the introduction of the subsidy policy in 2014 and has achieved faster development.Today,China’s new展开更多
This paper uses automatic vehicle location (AVL) records to investigate the effect of weather conditions on the travel time reliability of on-road rail transit, through a case study of the Melbourne streetcar (tram...This paper uses automatic vehicle location (AVL) records to investigate the effect of weather conditions on the travel time reliability of on-road rail transit, through a case study of the Melbourne streetcar (tram) network. The datasets available were an extensive historica; AVL dataset as well as weather observations. The sample size used in the analysis included all trips made over a period of five years (2006-2010 inclusive), during the morning peak (7 am-9 am) for fifteen randomly selected radial tram routes, all traveling to the Melbourne CBD create a linear model Ordinary least square (OLS) regression analysis was conducted to with tram travel time being the dependent variable. An alternative formulation of the model is also compared. Travel time was regressed on various weather effects including precipitation, air temperature, sea level pressure and wind speed; as well as indicator variables for weekends, public holidays and route numbers to investigate a correlation between weather condition and the on-time performance of the trams. The results indicate that only precipitation and air temperature are significant in their effect on tram travel time. The model demonstrates that on average, an additional millimeter of precipitation during the peak period adversely affects the average travel time during that period by approximately 8 s, that is, rainfall tends to increase the travel time. The effect of air temperature is less intuitive, with the model indicating that trams adhere more closely to schedule when the temperature is different in absolute terms to the mean operating conditions (taken as 15 ℃).展开更多
文摘Static strength finite element analysis was conducted to decrease the weight of a skeleton vehicle's frame. Results indicated that the maximum stress occurs on the front beam 's variable section area. Dynamic sensitivity analysis elucidated the relationship between the maximum stress and the thickness of a particular beam,e. g.,top,middle,and bottom beam. Displacement was analyzed by the key part that influenced the maximum stress. Finally,the new plan using BS960 super-high-strength beam steel and the preferred beam thickness was compared with the original plan. New combinations of beam thickness were introduced on the basis of different purposes; the maximum responding light w eight ratio was 21%.
文摘Security systems are a necessity for the deployment of smart vehicles in our society. Security in vehicular ad hoe networks is crucial to the reliable exchange of information and control data. In this paper, we propose an intelligent Intrusion Detection System (IDS) to protect the external communication of self-driving and semi self-driving vehicles. This technology has the ability to detect Denial of Service (DOS) and black hole attacks on vehicular ad hoe networks (VANETs). The advantage of the proposed IDS over existing security systems is that it detects attacks before they causes significant damage. The intrusion prediction technique is based on Linear Discriminant Analysis (LDA) and Quadratic Diseriminant Analysis (QDA) which are used to predict attacks based on observed vehicle behavior. We perform simulations using Network Simulator 2 to demonstrate that the IDS achieves a low rate of false alarms and high accuracy in detection.
基金supported by the National Basic Research Program of China (Grant 2011CB711103)the National Natural Science Foundation of China (Grants U1134202,U1361117)+2 种基金the Program for Changjiang Scholars and Innovative Research Team in University (IRT1178)the 2014 Doctoral Innovation Funds of Southwest Jiaotong Universitythe Fundamental Research Funds for the Central Universities
文摘The fexibility of a train's wheelset can have a large effect on vehicle–track dynamic responses in the medium to high frequency range.To investigate the effects of wheelset bending and axial deformation of the wheel web,a specifi coupling of wheel–rail contact with a fexible wheelset is presented and integrated into a conventional vehicle–track dynamic system model.Both conventional and the proposed dynamic system models are used to carry out numerical analyses on the effects of wheelset bending and axial deformation of the wheel web on wheel–rail rolling contact behaviors.Excitations with various irregularities and speeds were considered.The irregularities included measured track irregularity and harmonic irregularities with two different wavelengths.The speeds ranged from 200 to400km/h.The results show that the proposed model can characterize the effects of fexible wheelset deformation on the wheel–rail rolling contact behavior very well.
基金the National Natural Science Foundation of China(No.11302176)the Special Research Fund for the Doctoral Program of Higher Education of China(No.20126102120021)
文摘Static stability analysis of the two-point mooring autonomous underwater vehicle(AUV) is presented.The mathematic model is a set of equilibrium equations describing the attitude of the AUV.The mooring lines are regarded as inelastic catenaries,and five degrees of freedom of AUV are considered.The stability of the system is represented by inequality conditions between several physical quantities and the corresponding limitations.We analyze stability of the prime AUV and find that the AUV has a flow-following tendency,which makes the swing angle big.The result shows that the two-point mooring AUV can remain stable under 2.5 kn ocean current speed,and it will weigh anchor when the speed is greater than 3 kn.Subsequent parametric study reveals the influence of the designing parameters on the stability.
文摘1.The overall development of new energy vehicles was good in 2017.In early 2017,the new energy vehicle market was greatly affected by major policy adjustments such as drastic decline in new energy vehicle subsidies and re-examination of the model catalogue.But China’s determination to vigorously promote the healthy development of the new energy vehicle industry has not changed.In March and April。
文摘As a strategic emerging industry,the new energy vehicle industry has been a key industry in China in recent years and has great significance for China to realize industrial transformation and upgrading,and seize the commanding heights of international competition.In particular,the industry has been vigorously boosted by the introduction of the subsidy policy in 2014 and has achieved faster development.Today,China’s new
基金supported by the Australian Research Council(No.DE130100205)
文摘This paper uses automatic vehicle location (AVL) records to investigate the effect of weather conditions on the travel time reliability of on-road rail transit, through a case study of the Melbourne streetcar (tram) network. The datasets available were an extensive historica; AVL dataset as well as weather observations. The sample size used in the analysis included all trips made over a period of five years (2006-2010 inclusive), during the morning peak (7 am-9 am) for fifteen randomly selected radial tram routes, all traveling to the Melbourne CBD create a linear model Ordinary least square (OLS) regression analysis was conducted to with tram travel time being the dependent variable. An alternative formulation of the model is also compared. Travel time was regressed on various weather effects including precipitation, air temperature, sea level pressure and wind speed; as well as indicator variables for weekends, public holidays and route numbers to investigate a correlation between weather condition and the on-time performance of the trams. The results indicate that only precipitation and air temperature are significant in their effect on tram travel time. The model demonstrates that on average, an additional millimeter of precipitation during the peak period adversely affects the average travel time during that period by approximately 8 s, that is, rainfall tends to increase the travel time. The effect of air temperature is less intuitive, with the model indicating that trams adhere more closely to schedule when the temperature is different in absolute terms to the mean operating conditions (taken as 15 ℃).