BACKGROUND： Movement is an effective way to provide sensory, movement and reflectivity afferent stimulation to the central nervous system. Movement plays an important role in functional recombination and compensation...BACKGROUND： Movement is an effective way to provide sensory, movement and reflectivity afferent stimulation to the central nervous system. Movement plays an important role in functional recombination and compensation in the brain. OBJECTIVE： To observe movement training effects on texture parameters of synaptic interfaces in the sensorimotor cortex and hippocampal CA3 area of the ischemic hemisphere and on motor function in cerebral infarction rats. DESIGN, TIME AND SETTING： This neural morphology and pathology randomized controlled animal experiment was performed at the Center Laboratory, Affiliated Hospital of Luzhou Medical College, China from November 2004 to April 2005. MATERIALS： A total of 32 healthy male Wistar rats aged 8 weeks were equally and randomly assigned into model and movement training groups. METHODS： Rat models of right middle cerebral artery occlusion were established using the suture occlusion method in both groups. Rats in the movement training group underwent balance training, screen training, and rotating rod training starting on day 5 after surgery, for 40 minutes every day, 6 days per week, for 4 weeks. MAIN OUTCOME MEASURES： Texture parameters of synaptic interfaces were determined using a transmission electron microscope and image analyzer during week 5 following model induction. The following parameters were measured： synaptic cleft width; postsynaptic density thickness; synaptic interface curvature; and active zone length. Motor function was assessed using balance training, screen training, and rotating rod training. The lower score indicated a better motor function. RESULTS： The postsynaptic density thickness, synaptic interface curvature, and active zone length were significantly increased in the sensorimotor cortex and hippocampal CA3 area of the ischemic hemisphere of rats from the movement training group compared with the model group （P 〈 0.05 or 0.01）. Curved synapses and perforated synapses were seen in the sensorimotor cortex and hippocampal CA3 area at the ischemic hemisphere of rats from the movement training group, while fiat synapses were found in the model group. Balance training, screen training, and rotating rod training scores were lower in the movement training group than the model group （P 〈 0.05）. CONCLUSION： Movement training enhances synaptic plasticity in the sensorimotor cortex and, hippocampal CA3 area at the ischemic hemisphere of cerebral infarction rats, and promotes the recovery of motor function.展开更多
Different from limb rehabilitation training,the purpose of muscle strength training is to reduce muscle atrophy and increase muscle strength and tolerance through strength training of limb muscles,and then improve the...Different from limb rehabilitation training,the purpose of muscle strength training is to reduce muscle atrophy and increase muscle strength and tolerance through strength training of limb muscles,and then improve the muscle strength level of muscles(groups),mainly for sports fitness and muscle strengthening groups and patients with muscle atrophy or muscle weakness caused by various diseases.In this paper,we developed a new reconfigurable muscle strength training robot,a bionic robot by imitating physicians to conduct muscle strength training for patients,which was developed with six training modes for 17 joint movements,that is,the shoulder flexion/extension,the shoulder internal/external rotation,the shoulder adduction/abduction,the elbow flexion/extension,the wrist supination/pronation,the wrist flexion/extension,the wrist radial/ulnar deviation,the hip flexion/extension,the hip internal/external rotation,the hip adduction/abduction,the knee flexion/extension,the ankle dorsiflexion/plantarflexion,the ankle adduction/abduction,the ankle inversion/eversion,the waist flexion/extension,the waist left/right rotation,and the waist left/right flexion.The reconfigurable mechanism was designed with fully electric adjuster and reconfigurable adaptors deployed on the driving unit,and six training modes were developed,namely,continuous passive motion,active exercise,passive–active exercise,isotonic exercise,isometric exercise and isokinetic exercise.Experiments with knee joint and elbow joint have shown that the developed reconfigurable muscle strength training robot can realize the multi-mode trainings for the 17 joint movements.展开更多
Statement of the Problem: Upper limb hemiparesis is a common impairment underlying disability after Stroke. Transfer of treatment to daily functioning remains a question for traditional approaches used in treatment of...Statement of the Problem: Upper limb hemiparesis is a common impairment underlying disability after Stroke. Transfer of treatment to daily functioning remains a question for traditional approaches used in treatment of upper extremity hemiparesis. Approaches based on Motor Learning principles may facilitate the transfer of treatment to activities of daily living. Methodology: Forty one subjects with chronic stroke, attending department of occupational therapy, National Institute for the Orthopaedically Handicapped, Kolkata, West Bengal, India participated in a single blinded randomized pre-test and post-test control group training study. Subjects were randomized over three intervention groups receiving modified Constraint Induced Movement Therapy (n = 13), Bilateral Arm training (n = 14), and an equally intensive conventional treatment program (n = 14). Subjects in the bilateral arm training group participated in bilateral symmetrical activities, where as subjects in constraint induced movement therapy group performed functional activities with the affected arm only and conventional group received conventional Occupational Therapy. Each group received intensive training for 1 hour/day, 5 days/week, for 8 weeks. Pre-treatment and post-treatment measures included the Fugl-Meyer measurement of physical performance (FMA- upper extremity section), action research arm test, motor activity log. Assessments were administered by a rater blinded to group assignment. Result: Both m-CIMT (p = 0.01) and bilateral arm training (p = 0.01) group showed statistically significant improvement in upper extremity functioning on Action Research Arm Test score in comparison to the conventional therapy group (p = 0.33). The bilateral arm training group had significantly greater improvement in upper arm function (Proximal Fugl-Meyer Assessment score, p = 0.001);while the constraint induced movement therapy group had greater improvement of hand functions (Distal Fugl-Meyer Assessment score, p = 0.001. There is an improvement seen in Quality of movement in the Conventional Therapy group. (p = 0.001). Conclusion: Both the treatment techniques can be used for upper extremity management in patients with chronic stroke. Bilateral arm training may be used to improve upper arm function and m-CIMT may be used to improve hand functions, while the group that received modified constraint induced movement therapy had greater improvement.展开更多
Objectives:To examine the effects of finger-movement exercises and finger weight-lift training on handgrip strength and Activities of Daily Living Scale(ADLS)values.Methods:A total of 80 very elderly adults(aged80 ye...Objectives:To examine the effects of finger-movement exercises and finger weight-lift training on handgrip strength and Activities of Daily Living Scale(ADLS)values.Methods:A total of 80 very elderly adults(aged80 years)were assigned to either an intervention group(n?40)or a control group(n?40).Subjects in the intervention group performed finger-movement exercises and weight-lift training for a period of 3 months,while subjects in the control group received no intervention,and were unaware of the interventions received in the other group.Results:After completing 3 months of finger-movement exercises and weight-lift training,the average handgrip strength of the 40 participants in the intervention group had increased by 2.1 kg,whereas that in the control group decreased by 0.27 kg(P<0.05).After receiving intervention,the number of subjects in the intervention group with an ADLS score>22 points decreased by 7.5%(P<0.05,vs.pre-intervention).Conclusions:The combined use interventionwith finger-movement exercises and proper finger weight-lift training improved the handgrip strength andADLS values of very elderly individuals.These rehabilitation exercisesmay be used to help the elderlymaintain their self-care abilities.展开更多
In this paper, we propose a new formula of the real-time minimum safety headway based on the relative velocity of consecutive trains and present a dynamic model of high-speed passenger train movements in the rail line...In this paper, we propose a new formula of the real-time minimum safety headway based on the relative velocity of consecutive trains and present a dynamic model of high-speed passenger train movements in the rail line based on the proposed formula of the minimum safety headway. Moreover, we provide the control strategies of the high-speed passenger train operations based on the proposed formula of the real-time minimum safety headway and the dynamic model of highspeed passenger train movements. The simulation results demonstrate that the proposed control strategies of the passenger train operations can greatly reduce the delay propagation in the high-speed rail line when a random delay occurs.展开更多
This paper presents a discrete-time model to describe the movements of a group of trains, in which some operational strategies, including traction operation, braking operation and impact of stochastic disturbance, are...This paper presents a discrete-time model to describe the movements of a group of trains, in which some operational strategies, including traction operation, braking operation and impact of stochastic disturbance, are defined. To show the dynamic characteristics of train traffic flow with stochastic disturbance, some numerical experiments on a railway line are simulated. The computational results show that the discrete-time movement model can well describe the movements of trains on a rail line with the moving-block signalling system. Comparing with the results of no disturbance, it finds that the traffic capacity of the rail line will decrease with the influence of stochastic disturbance. Additionally, the delays incurred by stochastic disturbance can be propagated to the subsequent trains, and then prolong their traversing time on the rail line. It can provide auxiliary information for rescheduling trains When the stochastic disturbance occurs on the railway.展开更多
In this paper, we propose a new cellular automaton （CA） model for train movement simulations under mixed traffic conditions. A kind of control strategy is employed for trains to reduce energy consumption. In the pro...In this paper, we propose a new cellular automaton （CA） model for train movement simulations under mixed traffic conditions. A kind of control strategy is employed for trains to reduce energy consumption. In the proposed CA model, the driver controls the train movements by using some updated rules. In order to obtain a good insight into the evolution behaviours of the rail traffic flow, we investigate the space-time diagram of the rail traffic flow and the trajectories of the train movements. The numerical simulation results demonstrate that the proposed CA model can well describe the dynamic behaviours of the train movements. Some complex phenomena of train movements can be reproduced, such as the train delay propagations, etc.展开更多
The aim of this paper is to present a discrete event model-based approach to simulate train movement with the con- sidered energy-saving factor. We conduct extensive case studies to show the dynamic characteristics of...The aim of this paper is to present a discrete event model-based approach to simulate train movement with the con- sidered energy-saving factor. We conduct extensive case studies to show the dynamic characteristics of the traffic flow and demonstrate the effectiveness of the proposed approach. The simulation results indicate that the proposed discrete event model-based simulation approach is suitable for characterizing the movements of a group of trains on a single railway line with less iterations and CPU time. Additionally, some other qualitative and quantitative characteristics are investigated. In particular, because of the cumulative influence from the previous trains, the following trains should be accelerated or braked frequently to control the headway distance, leading to more energy consumption.展开更多
Based on a car-following model, in this paper, we propose a new traffic model for simulating train movement in railway traffic. In the proposed model, some realistic characteristics of train movement are considered, s...Based on a car-following model, in this paper, we propose a new traffic model for simulating train movement in railway traffic. In the proposed model, some realistic characteristics of train movement are considered, such as the distance headway and the safety stopping distance. Using the proposed traffic model, we analyse the space-time diagram of traffic flow, the trajectory of train movement, etc. Simulation results demonstrate that the proposed model can be successfully used for simulating the train movement. Some complex phenomena can be reproduced, such as the complex acceleration and deceleration of trains and the propagation of train delay.展开更多
Based on the optimal velocity car-following model, in this paper, we propose an improved model for simulating train movement in an urban railway in which the regenerative energy of a train is considered. Here a new ad...Based on the optimal velocity car-following model, in this paper, we propose an improved model for simulating train movement in an urban railway in which the regenerative energy of a train is considered. Here a new additional term is introduced into a traditional car-following model. Our aim is to analyze and discuss the dynamic characteristics of the train movement when the regenerative energy is utilized by the electric locomotive. The simulation results indicate that the improved car-following model is suitable for simulating the train movement. Further, some qualitative relationships between regenerative energy and dynamic characteristics of a train are investigated, such as the measurement data of regenerative energy presents a power-law distribution. Our results are useful for optimizing the design and plan of urban railway systems.展开更多
Based on optimM velocity car-following model, in this paper, we propose a new railway tramc model for describing the process of train movement control. In the proposed model, we give an improved form of the optimal ve...Based on optimM velocity car-following model, in this paper, we propose a new railway tramc model for describing the process of train movement control. In the proposed model, we give an improved form of the optimal velocity function V^opt, which is considered as the desired velocity function for train movement control under different control conditions. In order to test the proposed model, we simulate and analyze the trajectories of train movements, moreover, discuss the relationship curves between the train allowable velocity and the site of objective point in detail. Analysis results indicate that the proposed model can well capture some realistic futures of train movement control.展开更多
Research on the distribution of smoke in tunnels is significant for the fire emergency rescue after an operating metro train catches fire. A dynamic grid technique was adopted to research the law of smoke flow diffusi...Research on the distribution of smoke in tunnels is significant for the fire emergency rescue after an operating metro train catches fire. A dynamic grid technique was adopted to research the law of smoke flow diffusion inside the tunnel when the bottom of a metro train was on fire and to compare the effect of longitudinal ventilation modes on the smoke motion when the burning train stopped. Research results show that the slipstream curves around the train obtained by numerical simulation are consistent with experimental data. When the train decelerates, the smoke flow first extends to the tail of the train. With the decrease of the train's speed, the smoke flow diffuses to the head of the train. After the train stops, the slipstream around the train formed in the process of train operation plays a leading role in the smoke diffusion in the tunnel. The smoke flow quickly diffuses to the domain in front of the train. After forward mechanical ventilation is provided, the smoke flow inside the tunnel continues to diffuse downstream. When reverse mechanical ventilation operates, the smoke in front of the train flows back rapidly and diffuses to the rear of the train.展开更多
Optimizing train movement has a great significance for railway traffic. In this paper, based on the optimal velocity car-following model, we propose a new simulation model for optimizing train movement in railway traf...Optimizing train movement has a great significance for railway traffic. In this paper, based on the optimal velocity car-following model, we propose a new simulation model for optimizing train movement in railway traffic. Here a kind of single-track railway is considered. Our aim is to reduce the energy consumption of train movement and ensure the train being on time by controlling the velocity curve of train movement. The simulation results indicate that the proposed model is effective for optimizing train movement. In addition, some major characteristics of train movement can be well captured. This method provides a new way to optimize train movement in railway traffic.展开更多
In this paper, we propose an improved walk model for simulating the train movement on railway network. In the proposed method, walkers represent trains. The improved walk model is a kind of the network-based simulatio...In this paper, we propose an improved walk model for simulating the train movement on railway network. In the proposed method, walkers represent trains. The improved walk model is a kind of the network-based simulation analysis model. Using some management rules for walker movement, walker can dynamically determine its departure and arrival times at stations. In order to test the proposed method, we simulate the train movement on a part of railway network. The numerical simulation and analytical results demonstrate that the improved model is an effective tool for simulating the train movement on railway network. Moreover, it can well capture the characteristic behaviors of train scheduling in railway traffic.展开更多
The shot put is a sport that requires very high explosive power and precise technique.Strength training occupies the core position in the training of shot-putters,which can not only improve the throwing distance of at...The shot put is a sport that requires very high explosive power and precise technique.Strength training occupies the core position in the training of shot-putters,which can not only improve the throwing distance of athletes but also enhance their competitive state and prevent sports injuries.The purpose of this paper is to analyze the principles,classification,methods,and specific exercises of strength training in the training of shot-putters,in order to provide scientific training guidance for shot-putters.展开更多
With acquisition and accumulation of new data of structural geological investigations and high-resolution isotopic dating data, we have greatly improved our understanding of the tectonic events occurring in eastern Ch...With acquisition and accumulation of new data of structural geological investigations and high-resolution isotopic dating data, we have greatly improved our understanding of the tectonic events occurring in eastern China during the period from the Late Jurassic to Early Cretaceous and may give a new interpretation of the nature, timing and geodynamic settings of the “Yanshan Movement”. During the Mid-Late Jurassic （165±5 Ma）, great readjustment of plate amalgamation kinematics took place in East Asia and the tectonic regime underwent great transformation, thus initiating a new tectonic regime in which the North China Block was the center and different plates converged toward it from the north, east and southwest and forming the “East Asia convergent” tectonic system characterized by intracontinental subduction and orogeny. As a consequence, the crustal lithosphere of the East Asian continent thickened considerably during the Late Jurassic, followed immediately by Early Cretaceous substantial lithospheric thinning and craton destruction featured by drastic lithospheric extension and widespread volcano-magmatic activities, resulting in a major biotic turnover from the Yanliao biota to Jehol Biota. Such a tremendous tectonic event that took place in the continent of China and East Asia is the basic connotation of the “Yanshan Movement”. In the paper, according to the deformation patterns, geodynamic settings and deep processes, the “Yanshan Movement” is redefined as the Late Jurassic East Asian multi-directional plate convergent tectonic regime and its associated extensive intracontinental orogeny and great tectonic change that started at -165±5 Ma. The substantial lithospheric attenuation in East China is considered the post-effect of the Yanshanian intracontinental orogeny and deformation.展开更多
文摘BACKGROUND： Movement is an effective way to provide sensory, movement and reflectivity afferent stimulation to the central nervous system. Movement plays an important role in functional recombination and compensation in the brain. OBJECTIVE： To observe movement training effects on texture parameters of synaptic interfaces in the sensorimotor cortex and hippocampal CA3 area of the ischemic hemisphere and on motor function in cerebral infarction rats. DESIGN, TIME AND SETTING： This neural morphology and pathology randomized controlled animal experiment was performed at the Center Laboratory, Affiliated Hospital of Luzhou Medical College, China from November 2004 to April 2005. MATERIALS： A total of 32 healthy male Wistar rats aged 8 weeks were equally and randomly assigned into model and movement training groups. METHODS： Rat models of right middle cerebral artery occlusion were established using the suture occlusion method in both groups. Rats in the movement training group underwent balance training, screen training, and rotating rod training starting on day 5 after surgery, for 40 minutes every day, 6 days per week, for 4 weeks. MAIN OUTCOME MEASURES： Texture parameters of synaptic interfaces were determined using a transmission electron microscope and image analyzer during week 5 following model induction. The following parameters were measured： synaptic cleft width; postsynaptic density thickness; synaptic interface curvature; and active zone length. Motor function was assessed using balance training, screen training, and rotating rod training. The lower score indicated a better motor function. RESULTS： The postsynaptic density thickness, synaptic interface curvature, and active zone length were significantly increased in the sensorimotor cortex and hippocampal CA3 area of the ischemic hemisphere of rats from the movement training group compared with the model group （P 〈 0.05 or 0.01）. Curved synapses and perforated synapses were seen in the sensorimotor cortex and hippocampal CA3 area at the ischemic hemisphere of rats from the movement training group, while fiat synapses were found in the model group. Balance training, screen training, and rotating rod training scores were lower in the movement training group than the model group （P 〈 0.05）. CONCLUSION： Movement training enhances synaptic plasticity in the sensorimotor cortex and, hippocampal CA3 area at the ischemic hemisphere of cerebral infarction rats, and promotes the recovery of motor function.
基金supported in part by the National Key R&D Program of China(No.2018YFB1307004)in part by the National Natural Science Foundation of China(Nos.61903011 and 52175001)。
文摘Different from limb rehabilitation training,the purpose of muscle strength training is to reduce muscle atrophy and increase muscle strength and tolerance through strength training of limb muscles,and then improve the muscle strength level of muscles(groups),mainly for sports fitness and muscle strengthening groups and patients with muscle atrophy or muscle weakness caused by various diseases.In this paper,we developed a new reconfigurable muscle strength training robot,a bionic robot by imitating physicians to conduct muscle strength training for patients,which was developed with six training modes for 17 joint movements,that is,the shoulder flexion/extension,the shoulder internal/external rotation,the shoulder adduction/abduction,the elbow flexion/extension,the wrist supination/pronation,the wrist flexion/extension,the wrist radial/ulnar deviation,the hip flexion/extension,the hip internal/external rotation,the hip adduction/abduction,the knee flexion/extension,the ankle dorsiflexion/plantarflexion,the ankle adduction/abduction,the ankle inversion/eversion,the waist flexion/extension,the waist left/right rotation,and the waist left/right flexion.The reconfigurable mechanism was designed with fully electric adjuster and reconfigurable adaptors deployed on the driving unit,and six training modes were developed,namely,continuous passive motion,active exercise,passive–active exercise,isotonic exercise,isometric exercise and isokinetic exercise.Experiments with knee joint and elbow joint have shown that the developed reconfigurable muscle strength training robot can realize the multi-mode trainings for the 17 joint movements.
文摘Statement of the Problem: Upper limb hemiparesis is a common impairment underlying disability after Stroke. Transfer of treatment to daily functioning remains a question for traditional approaches used in treatment of upper extremity hemiparesis. Approaches based on Motor Learning principles may facilitate the transfer of treatment to activities of daily living. Methodology: Forty one subjects with chronic stroke, attending department of occupational therapy, National Institute for the Orthopaedically Handicapped, Kolkata, West Bengal, India participated in a single blinded randomized pre-test and post-test control group training study. Subjects were randomized over three intervention groups receiving modified Constraint Induced Movement Therapy (n = 13), Bilateral Arm training (n = 14), and an equally intensive conventional treatment program (n = 14). Subjects in the bilateral arm training group participated in bilateral symmetrical activities, where as subjects in constraint induced movement therapy group performed functional activities with the affected arm only and conventional group received conventional Occupational Therapy. Each group received intensive training for 1 hour/day, 5 days/week, for 8 weeks. Pre-treatment and post-treatment measures included the Fugl-Meyer measurement of physical performance (FMA- upper extremity section), action research arm test, motor activity log. Assessments were administered by a rater blinded to group assignment. Result: Both m-CIMT (p = 0.01) and bilateral arm training (p = 0.01) group showed statistically significant improvement in upper extremity functioning on Action Research Arm Test score in comparison to the conventional therapy group (p = 0.33). The bilateral arm training group had significantly greater improvement in upper arm function (Proximal Fugl-Meyer Assessment score, p = 0.001);while the constraint induced movement therapy group had greater improvement of hand functions (Distal Fugl-Meyer Assessment score, p = 0.001. There is an improvement seen in Quality of movement in the Conventional Therapy group. (p = 0.001). Conclusion: Both the treatment techniques can be used for upper extremity management in patients with chronic stroke. Bilateral arm training may be used to improve upper arm function and m-CIMT may be used to improve hand functions, while the group that received modified constraint induced movement therapy had greater improvement.
基金funded by the Aging Scientific Research Center in Zhejiang Province(ZRCA201013).
文摘Objectives:To examine the effects of finger-movement exercises and finger weight-lift training on handgrip strength and Activities of Daily Living Scale(ADLS)values.Methods:A total of 80 very elderly adults(aged80 years)were assigned to either an intervention group(n?40)or a control group(n?40).Subjects in the intervention group performed finger-movement exercises and weight-lift training for a period of 3 months,while subjects in the control group received no intervention,and were unaware of the interventions received in the other group.Results:After completing 3 months of finger-movement exercises and weight-lift training,the average handgrip strength of the 40 participants in the intervention group had increased by 2.1 kg,whereas that in the control group decreased by 0.27 kg(P<0.05).After receiving intervention,the number of subjects in the intervention group with an ADLS score>22 points decreased by 7.5%(P<0.05,vs.pre-intervention).Conclusions:The combined use interventionwith finger-movement exercises and proper finger weight-lift training improved the handgrip strength andADLS values of very elderly individuals.These rehabilitation exercisesmay be used to help the elderlymaintain their self-care abilities.
基金supported by the National Basic Research Program of China (Grant No. 2012CB725400)the National Natural Science Foundation of China (Grant No. 71131001-1)the Research Foundation of State Key Laboratory of Rail Traffic Control and Safety,Beijing Jiaotong University,China (Grant Nos. RCS2012ZZ001 and RCS2012ZT001)
文摘In this paper, we propose a new formula of the real-time minimum safety headway based on the relative velocity of consecutive trains and present a dynamic model of high-speed passenger train movements in the rail line based on the proposed formula of the minimum safety headway. Moreover, we provide the control strategies of the high-speed passenger train operations based on the proposed formula of the real-time minimum safety headway and the dynamic model of highspeed passenger train movements. The simulation results demonstrate that the proposed control strategies of the passenger train operations can greatly reduce the delay propagation in the high-speed rail line when a random delay occurs.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 70901006 and 60634010)the State Key Laboratory of Rail Traffic Control and Safety (Grant Nos. RCS2009ZT001 and RCS2008ZZ001)Beijing Jiaotong University, and the Innovation Foundation of Science and Technology for Excellent Doctorial Candidate of Beijing Jiaotong University (Grant No. 141034522)
文摘This paper presents a discrete-time model to describe the movements of a group of trains, in which some operational strategies, including traction operation, braking operation and impact of stochastic disturbance, are defined. To show the dynamic characteristics of train traffic flow with stochastic disturbance, some numerical experiments on a railway line are simulated. The computational results show that the discrete-time movement model can well describe the movements of trains on a rail line with the moving-block signalling system. Comparing with the results of no disturbance, it finds that the traffic capacity of the rail line will decrease with the influence of stochastic disturbance. Additionally, the delays incurred by stochastic disturbance can be propagated to the subsequent trains, and then prolong their traversing time on the rail line. It can provide auxiliary information for rescheduling trains When the stochastic disturbance occurs on the railway.
基金Project supported by the National Natural Science Foundation of China （Grant No 70471088）, the National Basic Research Program of China （Grant No 2006CB705500） and the Science and Technology Foundation of Beijing Jiaotong University （Grant No 2004SM026）.
文摘In this paper, we propose a new cellular automaton （CA） model for train movement simulations under mixed traffic conditions. A kind of control strategy is employed for trains to reduce energy consumption. In the proposed CA model, the driver controls the train movements by using some updated rules. In order to obtain a good insight into the evolution behaviours of the rail traffic flow, we investigate the space-time diagram of the rail traffic flow and the trajectories of the train movements. The numerical simulation results demonstrate that the proposed CA model can well describe the dynamic behaviours of the train movements. Some complex phenomena of train movements can be reproduced, such as the train delay propagations, etc.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.71271020 and 71271022)the Program for New Century Excellent Talents in University(Grant No.NCET-10-0218)
文摘The aim of this paper is to present a discrete event model-based approach to simulate train movement with the con- sidered energy-saving factor. We conduct extensive case studies to show the dynamic characteristics of the traffic flow and demonstrate the effectiveness of the proposed approach. The simulation results indicate that the proposed discrete event model-based simulation approach is suitable for characterizing the movements of a group of trains on a single railway line with less iterations and CPU time. Additionally, some other qualitative and quantitative characteristics are investigated. In particular, because of the cumulative influence from the previous trains, the following trains should be accelerated or braked frequently to control the headway distance, leading to more energy consumption.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 60634010 and 60776829)the New Century Excellent Talents in University,China (Grant No NCET-06-0074)the Key Project of Ministry of Education,China (GrantNo 107007)
文摘Based on a car-following model, in this paper, we propose a new traffic model for simulating train movement in railway traffic. In the proposed model, some realistic characteristics of train movement are considered, such as the distance headway and the safety stopping distance. Using the proposed traffic model, we analyse the space-time diagram of traffic flow, the trajectory of train movement, etc. Simulation results demonstrate that the proposed model can be successfully used for simulating the train movement. Some complex phenomena can be reproduced, such as the complex acceleration and deceleration of trains and the propagation of train delay.
基金Project supported by the National High Technology Research and Development Program of China(Grant No.2011AA110502)the National Natural Science Foundation of China(Grant No.71271022)
文摘Based on the optimal velocity car-following model, in this paper, we propose an improved model for simulating train movement in an urban railway in which the regenerative energy of a train is considered. Here a new additional term is introduced into a traditional car-following model. Our aim is to analyze and discuss the dynamic characteristics of the train movement when the regenerative energy is utilized by the electric locomotive. The simulation results indicate that the improved car-following model is suitable for simulating the train movement. Further, some qualitative relationships between regenerative energy and dynamic characteristics of a train are investigated, such as the measurement data of regenerative energy presents a power-law distribution. Our results are useful for optimizing the design and plan of urban railway systems.
基金Supported by the National Natural Science Foundation of China under Grant Nos.60634010 and 60776829the State Key Laboratory of Rail Traffic Control and Safety (Contract No.RCS2008ZZ001 and RCS2010ZZ001),Beijing Jiaotong University
文摘Based on optimM velocity car-following model, in this paper, we propose a new railway tramc model for describing the process of train movement control. In the proposed model, we give an improved form of the optimal velocity function V^opt, which is considered as the desired velocity function for train movement control under different control conditions. In order to test the proposed model, we simulate and analyze the trajectories of train movements, moreover, discuss the relationship curves between the train allowable velocity and the site of objective point in detail. Analysis results indicate that the proposed model can well capture some realistic futures of train movement control.
基金Project(U1134203)supported by the Major Program of the National Natural Science Foundation of ChinaProject(51105384)supported by the National Natural Science Foundation of China
文摘Research on the distribution of smoke in tunnels is significant for the fire emergency rescue after an operating metro train catches fire. A dynamic grid technique was adopted to research the law of smoke flow diffusion inside the tunnel when the bottom of a metro train was on fire and to compare the effect of longitudinal ventilation modes on the smoke motion when the burning train stopped. Research results show that the slipstream curves around the train obtained by numerical simulation are consistent with experimental data. When the train decelerates, the smoke flow first extends to the tail of the train. With the decrease of the train's speed, the smoke flow diffuses to the head of the train. After the train stops, the slipstream around the train formed in the process of train operation plays a leading role in the smoke diffusion in the tunnel. The smoke flow quickly diffuses to the domain in front of the train. After forward mechanical ventilation is provided, the smoke flow inside the tunnel continues to diffuse downstream. When reverse mechanical ventilation operates, the smoke in front of the train flows back rapidly and diffuses to the rear of the train.
基金Project supported by the National High Technology Research and Development Program of China (Grant No. 2011AA110502)the National Natural Science Foundation of China (Grant No. 71271022)
文摘Optimizing train movement has a great significance for railway traffic. In this paper, based on the optimal velocity car-following model, we propose a new simulation model for optimizing train movement in railway traffic. Here a kind of single-track railway is considered. Our aim is to reduce the energy consumption of train movement and ensure the train being on time by controlling the velocity curve of train movement. The simulation results indicate that the proposed model is effective for optimizing train movement. In addition, some major characteristics of train movement can be well captured. This method provides a new way to optimize train movement in railway traffic.
基金Supported by the National Natural Science Foundation of China under Grant Nos. 60634010 and 60776829New Century Excellent Talents in University under Grant No. NCET-06-0074
文摘In this paper, we propose an improved walk model for simulating the train movement on railway network. In the proposed method, walkers represent trains. The improved walk model is a kind of the network-based simulation analysis model. Using some management rules for walker movement, walker can dynamically determine its departure and arrival times at stations. In order to test the proposed method, we simulate the train movement on a part of railway network. The numerical simulation and analytical results demonstrate that the improved model is an effective tool for simulating the train movement on railway network. Moreover, it can well capture the characteristic behaviors of train scheduling in railway traffic.
文摘The shot put is a sport that requires very high explosive power and precise technique.Strength training occupies the core position in the training of shot-putters,which can not only improve the throwing distance of athletes but also enhance their competitive state and prevent sports injuries.The purpose of this paper is to analyze the principles,classification,methods,and specific exercises of strength training in the training of shot-putters,in order to provide scientific training guidance for shot-putters.
文摘With acquisition and accumulation of new data of structural geological investigations and high-resolution isotopic dating data, we have greatly improved our understanding of the tectonic events occurring in eastern China during the period from the Late Jurassic to Early Cretaceous and may give a new interpretation of the nature, timing and geodynamic settings of the “Yanshan Movement”. During the Mid-Late Jurassic （165±5 Ma）, great readjustment of plate amalgamation kinematics took place in East Asia and the tectonic regime underwent great transformation, thus initiating a new tectonic regime in which the North China Block was the center and different plates converged toward it from the north, east and southwest and forming the “East Asia convergent” tectonic system characterized by intracontinental subduction and orogeny. As a consequence, the crustal lithosphere of the East Asian continent thickened considerably during the Late Jurassic, followed immediately by Early Cretaceous substantial lithospheric thinning and craton destruction featured by drastic lithospheric extension and widespread volcano-magmatic activities, resulting in a major biotic turnover from the Yanliao biota to Jehol Biota. Such a tremendous tectonic event that took place in the continent of China and East Asia is the basic connotation of the “Yanshan Movement”. In the paper, according to the deformation patterns, geodynamic settings and deep processes, the “Yanshan Movement” is redefined as the Late Jurassic East Asian multi-directional plate convergent tectonic regime and its associated extensive intracontinental orogeny and great tectonic change that started at -165±5 Ma. The substantial lithospheric attenuation in East China is considered the post-effect of the Yanshanian intracontinental orogeny and deformation.
