The growing demand for capacity has prompted the rail industry to explore next-generation train control systems,such as train autonomous operation control systems,which transmit real-time information between trains wi...The growing demand for capacity has prompted the rail industry to explore next-generation train control systems,such as train autonomous operation control systems,which transmit real-time information between trains with the help of train-to-train communication.The communication delay affects the operation of the system.In addition,the train monitors real-time traffic information through on-board sensors.However,no measurement can be perfect,including sensors,which are affected by factors such as railway geometry and weather conditions.The sensor detection error is uncertain,resulting in multiple information uncertainties.Therefore,this paper proposes a train-following model based on the full velocity difference model by considering multiple information uncertainties and communication delay time to describe the autonomous operation of the train under a train autonomous operation control system.Based on this trainfollowing model,a stability analysis and numerical simulation of train traffic flow are carried out.The results show that when the velocity measured by the sensor is smaller than the real velocity or the headway monitored by the sensor is greater than the real headway,the delay will increase and continue to propagate and accumulate backward,resulting in blockage.Otherwise,the opposite occurs.These findings suggest that the effects of multiple information uncertainties are two-sided,depending on the degree of uncertainty of velocity information and headway information.In addition,communication delay time has little effect on train flow and delay.展开更多
Purpose–In recent years,the rapid advancement of artificial intelligence(AI)has exerted profound impacts on and provided strong impetus to numerous fields in the industrial sector.Within the railway industry,AI has d...Purpose–In recent years,the rapid advancement of artificial intelligence(AI)has exerted profound impacts on and provided strong impetus to numerous fields in the industrial sector.Within the railway industry,AI has driven continuous upgrading and optimization of intelligent train control technology,thanks to its enhanced computational capabilities derived from advanced algorithms and models,as well as its role in improving safety performance.Integrating AI technology more extensively into train autonomous driving and control has thus become an inevitable trend in the global development of railways.Design/methodology/approach–This paper,therefore,conducts a comprehensive analysis of the development progress and current status of AI technology applications in the field of train driving and control on a global scale.It systematically sorts out and analyzes the advantages of various AI technologies and the positive impacts they bring to the upgrading of train control technology,elucidates the feasibility and future prospects of applying a range of emerging AI technologies from the perspective of technical theory and provides guidance for the intelligent development of this field from a practical perspective.Findings–The application of AI technology in the train driving and control field is still in its infancy.While a large number of AI technologies have been widely adopted,there remains significant room for further optimization and improvement of these technologies.Additionally,a variety of AI technologies that have been applied in other industrial sectors but not yet widely implemented in training autonomous driving and control have demonstrated tremendous development potential.Originality/value–The research findings provide references and guidance for advancing train control technology,promoting the digital transformation of railways,accelerating the overall optimization and upgrading of railway industry technologies,and facilitating the accelerated development of global railways.展开更多
OBJECTIVE: To investigate the effects of acupuncture therapy compared with sham acupuncture on heart rate variability(HRV) in 24 elite soccer players during 4-week, high-intensity training sessions.METHODS: The subjec...OBJECTIVE: To investigate the effects of acupuncture therapy compared with sham acupuncture on heart rate variability(HRV) in 24 elite soccer players during 4-week, high-intensity training sessions.METHODS: The subjects were randomly divided into two groups: acupuncture group(AG) and sham acupuncture group(SG). In addition, AG had been implemented two times/week to stimulate Zusanli(ST 36), Hegu(LI 4), Shenshu(BL 23), and Chize(LU5). While SG, had been applied to utilize a special "placebo-needle" technique on the same sites.What's more, the HRV parameters were calculated before and after interventions, respectively.RESULTS: First, stress index(SI) had a significantly increased in SG(P = 0.031) compare pre-test with post-test, however, no significantly difference in AG(P = 0.102). Secondly, standard deviation of N-N intervals(SNDD) have enormously significantly high-er in AG when comparing baseline with post therapy(P = 0.001), while, declined in SG(P = 0.827).Meanwhile, the root mean square of successive differences(RMSSD) were significant differences in AG(P = 0.023). What's more, when the high-frequency(HF) were significantly higher in AG(P = 0.047) after receiving the acupuncture therapy, the lowe-frequency(LF) power were decreased but no significant in AG and SG. Comparing with pre-experiment, the ratio of LF/HF was lower in AG, but higher in SG. Furthermore, it was significant difference when compare the post-experiment parameters of AG with SG(P = 0.015). And HF parameters have significance(P = 0.005) compare between two groups during the post-experiment.CONCLUSION: Based on evidence, acupuncture therapy on special acupoints could strengthen the parasympathetic nervous activity and modulates the balance between parasympathetic and sympathetic activity in soccer players while they engage in high-intensity training.展开更多
As a development direction of urban rail transit system,the train autonomous circumambulate system(TACS)can operate in a safer,more efficient,and more economical mode.However,most urban rail transit systems transmit s...As a development direction of urban rail transit system,the train autonomous circumambulate system(TACS)can operate in a safer,more efficient,and more economical mode.However,most urban rail transit systems transmit signals through industrial,scientific,and medical(ISM)frequency bands or narrow frequency bands,which cannot meet the requirements of TACS.As a promising solution,the 5th generation(5G)mobile communication provides more services for the future urban rail transit systems,and covers the shortages of exiting communication technologies in terms of capacity and reliability.In this paper,we first briefly review the research status of current train control system and introduce its limitations.Next,we propose a novel network architecture,and present new technologies and requirements of the proposed architecture for TACS.Some potential challenges are then discussed to give insights for further research of TACS.展开更多
基金supported by Beijing Natural Science Foundation(Grant No.L231009)the National Natural Science Foundation of China(Grant No.72288101)the Fundamental Research Funds for the Central Universities(Grant No.2022JBZY017)。
文摘The growing demand for capacity has prompted the rail industry to explore next-generation train control systems,such as train autonomous operation control systems,which transmit real-time information between trains with the help of train-to-train communication.The communication delay affects the operation of the system.In addition,the train monitors real-time traffic information through on-board sensors.However,no measurement can be perfect,including sensors,which are affected by factors such as railway geometry and weather conditions.The sensor detection error is uncertain,resulting in multiple information uncertainties.Therefore,this paper proposes a train-following model based on the full velocity difference model by considering multiple information uncertainties and communication delay time to describe the autonomous operation of the train under a train autonomous operation control system.Based on this trainfollowing model,a stability analysis and numerical simulation of train traffic flow are carried out.The results show that when the velocity measured by the sensor is smaller than the real velocity or the headway monitored by the sensor is greater than the real headway,the delay will increase and continue to propagate and accumulate backward,resulting in blockage.Otherwise,the opposite occurs.These findings suggest that the effects of multiple information uncertainties are two-sided,depending on the degree of uncertainty of velocity information and headway information.In addition,communication delay time has little effect on train flow and delay.
文摘Purpose–In recent years,the rapid advancement of artificial intelligence(AI)has exerted profound impacts on and provided strong impetus to numerous fields in the industrial sector.Within the railway industry,AI has driven continuous upgrading and optimization of intelligent train control technology,thanks to its enhanced computational capabilities derived from advanced algorithms and models,as well as its role in improving safety performance.Integrating AI technology more extensively into train autonomous driving and control has thus become an inevitable trend in the global development of railways.Design/methodology/approach–This paper,therefore,conducts a comprehensive analysis of the development progress and current status of AI technology applications in the field of train driving and control on a global scale.It systematically sorts out and analyzes the advantages of various AI technologies and the positive impacts they bring to the upgrading of train control technology,elucidates the feasibility and future prospects of applying a range of emerging AI technologies from the perspective of technical theory and provides guidance for the intelligent development of this field from a practical perspective.Findings–The application of AI technology in the train driving and control field is still in its infancy.While a large number of AI technologies have been widely adopted,there remains significant room for further optimization and improvement of these technologies.Additionally,a variety of AI technologies that have been applied in other industrial sectors but not yet widely implemented in training autonomous driving and control have demonstrated tremendous development potential.Originality/value–The research findings provide references and guidance for advancing train control technology,promoting the digital transformation of railways,accelerating the overall optimization and upgrading of railway industry technologies,and facilitating the accelerated development of global railways.
文摘OBJECTIVE: To investigate the effects of acupuncture therapy compared with sham acupuncture on heart rate variability(HRV) in 24 elite soccer players during 4-week, high-intensity training sessions.METHODS: The subjects were randomly divided into two groups: acupuncture group(AG) and sham acupuncture group(SG). In addition, AG had been implemented two times/week to stimulate Zusanli(ST 36), Hegu(LI 4), Shenshu(BL 23), and Chize(LU5). While SG, had been applied to utilize a special "placebo-needle" technique on the same sites.What's more, the HRV parameters were calculated before and after interventions, respectively.RESULTS: First, stress index(SI) had a significantly increased in SG(P = 0.031) compare pre-test with post-test, however, no significantly difference in AG(P = 0.102). Secondly, standard deviation of N-N intervals(SNDD) have enormously significantly high-er in AG when comparing baseline with post therapy(P = 0.001), while, declined in SG(P = 0.827).Meanwhile, the root mean square of successive differences(RMSSD) were significant differences in AG(P = 0.023). What's more, when the high-frequency(HF) were significantly higher in AG(P = 0.047) after receiving the acupuncture therapy, the lowe-frequency(LF) power were decreased but no significant in AG and SG. Comparing with pre-experiment, the ratio of LF/HF was lower in AG, but higher in SG. Furthermore, it was significant difference when compare the post-experiment parameters of AG with SG(P = 0.015). And HF parameters have significance(P = 0.005) compare between two groups during the post-experiment.CONCLUSION: Based on evidence, acupuncture therapy on special acupoints could strengthen the parasympathetic nervous activity and modulates the balance between parasympathetic and sympathetic activity in soccer players while they engage in high-intensity training.
基金This work was supported in part by the National Natural Science Foundation of China(U2001213,61971191 and 61661021)in part by the Beijing Natural Science Foundation under Grant L182018 and L201011,in part by National Key Research and Development Project(2020YFB1807204)+1 种基金in part by the open project of Shanghai Institute of Microsystem and Information Technology(20190910)in part by the Key project of Natural Science Foundation of Jiangxi Province(20202ACBL202006).
文摘As a development direction of urban rail transit system,the train autonomous circumambulate system(TACS)can operate in a safer,more efficient,and more economical mode.However,most urban rail transit systems transmit signals through industrial,scientific,and medical(ISM)frequency bands or narrow frequency bands,which cannot meet the requirements of TACS.As a promising solution,the 5th generation(5G)mobile communication provides more services for the future urban rail transit systems,and covers the shortages of exiting communication technologies in terms of capacity and reliability.In this paper,we first briefly review the research status of current train control system and introduce its limitations.Next,we propose a novel network architecture,and present new technologies and requirements of the proposed architecture for TACS.Some potential challenges are then discussed to give insights for further research of TACS.
