This paper describes the development and optimization plans for the China Railway Express(CR Express).As a new type of international land transport organization,CR Express has emerged with the continuous expansion of ...This paper describes the development and optimization plans for the China Railway Express(CR Express).As a new type of international land transport organization,CR Express has emerged with the continuous expansion of China toward European investment and trade,and in particular,has expanded with the continuous progress of the One Belt and One Road(OBOR)initiative.In addition to improving the service quality of CR Express,the operating costs must be reduced for developing“smart railways”that serve“smart cities”.We propose a dualobjective-based function mathematical optimization model;the satisfaction of the cargo owner is considered,and the timeliness,transportation capacity,and goods category constraints of CR Express transportation are designed.Moreover,we present the normalized equivalent method of the two-objective function of the model.Finally,a case study is conducted against the background of certain trains in the western corridor of CR Express to validate the effectiveness of the model and research methods proposed in this study.展开更多
Railway is the backbone of Chinese transportation system,but its poor quality of services for passengers cause complains now and then.This study first analyzed the influencing factors of service quality on railway pas...Railway is the backbone of Chinese transportation system,but its poor quality of services for passengers cause complains now and then.This study first analyzed the influencing factors of service quality on railway passenger,and its quality characteristics was also explained,and finally we proposed an evaluation system of service quality on railway passenger transport.Through the statistical analysis and processing of the basic information from survey data from railway station,trains and the official website of the ticket purchase,the evaluation score of question naire was converted into the score in evaluation index system,which was based on SERVQUAL model.Finally,the evaluation index system was applied to the field test,and all levels of indicators and the overall evaluation of railway passenger transport service quality was obtained.The relevant results show that the evaluation model of this study is concise and practical,and the method has certain practicability and promotion value,which is beneficial to the department of management supervision in railway transportation.展开更多
Nowadays, because of its wide bandwidth and high communication capability, the optical fiber is more and more used for high data rate transmission of information in railway environments. Conventionally, only one servi...Nowadays, because of its wide bandwidth and high communication capability, the optical fiber is more and more used for high data rate transmission of information in railway environments. Conventionally, only one service is sent over the fiber at a time. However, many different services can be simultaneously conveyed in railway stations such as passenger information service, cellular phone, Wi-Fi... The objective of the work proposed in this paper is to demonstrate the potential benefits of transmitting radio signals over fiber in a railway environment. The main idea is to exploit the full capacity of the fiber by transmitting multiple services using the same fiber. Since, different services are operating in different frequency bands; we propose a new multiplexing technique called Mode Group Diversity Multiplexing (MGDM) to ensure the transmission of multiple services using the same fiber, without additional infrastructure. There are numerous advantages of the proposed technique, e.g., faster and reliable data exchange, high resolution video surveillance capability, high data rate information exchange in railway stations. We present, in this paper, the physical characteristics of optical fibers, performance of MGDM multiplexing technique, and the influence of the laser excitation conditions at the entrance of the fiber on the performances of the system.展开更多
Expansive soil is sensitive to dry and wet environment change. And the volume deformation and inflation pressure of expansive soil may induce to cause the deformation failure of roadbed or many other adverse effects. ...Expansive soil is sensitive to dry and wet environment change. And the volume deformation and inflation pressure of expansive soil may induce to cause the deformation failure of roadbed or many other adverse effects. Aimed at a high-speed railway engineering practice in the newly built Yun-Gui high-speed railway expansive soil section in China, indoor vibration test on a full-scaled new cutting subgrade model is carried out. Based on the established track-subgrade-foundation of expansive soil system dynamic model test platform, dynamic behavior of new cutting subgrade structure under train loads coupling with extreme service environment(dry, raining, and groundwater level rising) is analyzed comparatively. The results show that the subgrade dynamic response is significantly influenced by service conditions and the dynamic response of subgrade gradually becomes stable with the increasing vibration times under various service environment conditions. The vertical dynamic soil stress is related with the depth in an approximate exponential function, and the curves of vertical dynamic soil stress present a "Z" shape distribution along transverse distance. The peak value of dynamic soil stress appears below the rail, and it increases more obviously near the roadbed surface. However, the peak value of dynamic soil stress is little affected outside 5.0 m of center line. The vibration velocity and acceleration are in a quadratic curve with an increase in depth, and the raining and groundwater level rising increase both the vibration velocity and the acceleration. The vertical deformations at different depths are differently affected by service environment in roadbed. The deformation of roadbed increases sharply when the water gets in the foundation of expansive soil, and more than 60% of the total deformation of roadbed occurs in expansive soil foundation. The laid waterproofing and drainage structure layer, which weakens the dynamic stress and improves the track regularity, presents a positive effect on the control deformation of roadbed surface. An improved empirical formula is then proposed to predict the dynamic stress of ballasted tracks subgrade of expansive soil.展开更多
Rail transport has and continues to play a key role in the movement of goods and passengers in many countries around the world including Nigeria.However,while rail transport continues to enjoy relative importance in t...Rail transport has and continues to play a key role in the movement of goods and passengers in many countries around the world including Nigeria.However,while rail transport continues to enjoy relative importance in terms of investment,growth and contribution to the national economy in several countries,it has suffered and declined(in terms of modal share contribution which has led to decreased patronage)in Nigeria.However,there are new developments and investment on rail and some measures are being put in place to revive the Nigerian rail transport system.As these new developments and rehabilitations are going on,it will be imperative to know what the users/customers think as well,so that they are not left out because under normal circumstances,customers need transport services and not rail transport services.Therefore,if they were not satisfied with rail transport services they would simply turn to other modes of transport.As part of an on-going PhD research project,this paper focuses on the perceptions of Nigerian rail transport users/customers regarding the quality of rail services provided.Data was collected by the use of structured/semi-structured questionnaires,which were distributed,to the respondents.The study sample included 474 respondents between the age range of 20-70 out of which just 21(4.4%)have used rail transport;this low patronage figure is as a result of the long time neglect of the Nigerian rail transport system while 474(100%)of the correspondents use road transport daily which has led to an increasing pressure on road transport and infrastructures.Data was collected respectively from the following cities:Lagos,Warri,Ughelli and Benin.展开更多
In view of the problems of inconsistent data semantics,inconsistent data formats,and difficult data quality assurance between the railway engineering design phase and the construction and operation phase,as well as th...In view of the problems of inconsistent data semantics,inconsistent data formats,and difficult data quality assurance between the railway engineering design phase and the construction and operation phase,as well as the difficulty in fully realizing the value of design results,this paper proposes a design and implementation scheme for a railway engineering collaborative design platform.The railway engineering collaborative design platform mainly includes functional modules such as metadata management,design collaboration,design delivery management,model component library,model rendering services,and Building Information Modeling(BIM)application services.Based on this,research is conducted on multi-disciplinary parameterized collaborative design technology for railway engineering,infrastructure data management and delivery technology,and design multi-source data fusion and application technology.The railway engineering collaborative design platform is compared with other railway design software to further validate its advantages and advanced features.The platform has been widely applied in multiple railway construction projects,greatly improving the design and project management efficiency.展开更多
China’s railway network transported 1.004 billion tonnes of cargo in the third quarter of this year,marking a year-on-year increase of 3.8 percent and setting a new record for freight volume in a single quarter,offic...China’s railway network transported 1.004 billion tonnes of cargo in the third quarter of this year,marking a year-on-year increase of 3.8 percent and setting a new record for freight volume in a single quarter,official data showed on 20 October.China’s railway industry has been improving its transportation services and efficiency to support the high-quality development of the economy,according to China State Railway Group Co.,Ltd.展开更多
With 2025 going to be a special year for China-Europe ties,2024 has provided many inspirations,from a milestone in the China-Europe train service to a new center for cooperation.THE Yiwu-Madrid freight railway route,t...With 2025 going to be a special year for China-Europe ties,2024 has provided many inspirations,from a milestone in the China-Europe train service to a new center for cooperation.THE Yiwu-Madrid freight railway route,the longest in the world,crisscrossing over 13,000 kilometers and covering eight countries,celebrated its 10th anniversary last November.展开更多
Technological advancement in the field of trans- portation and communication has been happening at a faster pace in the past few decades. As the demand for high-speed transportation increases, the need for an improved...Technological advancement in the field of trans- portation and communication has been happening at a faster pace in the past few decades. As the demand for high-speed transportation increases, the need for an improved seamless communication system to handle higher data traffic in a highly mobile environment becomes imperative. This paper proposes a novel scheme to enhance the quality of service in high-speed railway (HSR) communication environment using the concept of torch nodes (TNs) and adaptive measurement aggregation (AMA). The system was modeled using an object-oriented discrete event sim- ulator, and the performance was analyzed against the existing single-antenna scheme. The simulation results show that the proposed scheme with its minimal imple- mentation overhead can efficiently perform seamless han- dover with reduced handover failure and communication interruption probability.展开更多
Purpose–This study aims to investigate the service performances of a new full-section asphalt concrete waterproof sealing structure(FSACWSS)for the high-speed railway subgrade through on-site tracking,monitoring and ...Purpose–This study aims to investigate the service performances of a new full-section asphalt concrete waterproof sealing structure(FSACWSS)for the high-speed railway subgrade through on-site tracking,monitoring and post-construction investigation.Design/methodology/approach–Based on the working state of the waterproof sealing structure,the main functional characteristics were analyzed,and a kind of roller-compacted high elastic modulus asphalt concrete(HEMAC)was designed and evaluated by several groups of laboratory tests.It is applied to an engineering test section,and the long-term performance monitoring and subgrade dynamic performance testing system were installed to track and monitor working performances of the test section and the adjacent contrast section with fiber-reinforced concrete.Findings–Results show that both the dynamic performance of the track structure and the subgrade in the test section meet the requirements of the specification limits.The water content in the subgrade of the test section is maintained at 8–18%,which is less affected by the weather.However,the water content in the subgrade bed of the contrast section is 10–35%,which fluctuates significantly with the weather.The heat absorption effect of asphalt concrete in the test section makes the temperature of the subgrade at the shoulder larger than that in the contrastive section.The monitoring value of the subgrade vertical deformation in the test section is slightly larger than that in the contrastive section,but all of them meet the limit requirements.The asphalt concrete in the test section is in good contact with the base,and there are no diseases such as looseness or spalling.Only a number of cracks are found at the joints of the base plates.However,there are more longitudinal and lateral cracks in the contrastive section,which seriously affects the waterproof and sealing effects.Besides,the asphalt concrete is easier to repair,featuring good maintainability.Originality/value–This research can provide a basis for popularization and application of the asphalt concrete waterproof sealing structure in high-speed railways.展开更多
This is a review of high-speed train development in the sense of technology advances all over the world. Three generations of high-speed trains are classified according to their technical characteristics and maximum o...This is a review of high-speed train development in the sense of technology advances all over the world. Three generations of high-speed trains are classified according to their technical characteristics and maximum operating speed. Emphasis is given to the newly developed high-speed train in China, CRH380. The theoretical foundations and future development of CRH380 are briefly discussed.展开更多
In this paper,a beamforming scheme to improve the coverage in high-speed railway communication systems is investigated.A dedicated coverage model,where the coverage cell is an ellipse rather than the traditional circu...In this paper,a beamforming scheme to improve the coverage in high-speed railway communication systems is investigated.A dedicated coverage model,where the coverage cell is an ellipse rather than the traditional circular or linear,is considered.Based on the elliptical coverage cell,an optimization problem for the beamforming design is formulated to maximize the percentage of railway coverage,subject to the constraints on equal expected designed propagation gain(the gain obtained by a combination of designed beam and propagation channel)on the elliptical curve,i.e.,the expectation of designed propagation gain on the elliptical curve are all equal.Considering that the coverage can be improved by increasing the minimum designed propagation gain on the railway,the problem can be recast to maximizing the equal expected designed propagation gain on the elliptical curve.Subsequently,a beamforming design with an improved β-fairness power allocation,where the optimization problem is formulated to maximize the minimum expected received power over time with the constraints on elliptical cell based beamforming and mobile service amount,is proposed to further improve the coverage.An alternating iteration algorithm is developed to find the optimal beamforming vector and the instantaneous transmit power.Through numerical results,it is found that the beamforming designed on the elliptical curve covers longer railway than beamforming designed on the railway directly,and the coverage of elliptical cell based beamforming can be increased with the eccentricity.In addition,beamforming with the improvedβ-fairness power allocation can further improve the railway coverage and mobile service amount simultaneously.Moreover,it is shown that the larger eccentricity of the ellipse with appropriately chosen BS location,the larger coverage distance.展开更多
SUMMARIES OF TOP NEWS STORIES CHINA 358 km of New High-Speed Rail Introduced in First Four Months China put 581 km of new railway lines into service in the first four months of the year,including 358 km of high-speed ...SUMMARIES OF TOP NEWS STORIES CHINA 358 km of New High-Speed Rail Introduced in First Four Months China put 581 km of new railway lines into service in the first four months of the year,including 358 km of high-speed railway。展开更多
The durability and reliability of slab track structures are essential for the long-term safety and stable operation of high-speed railways.In order to provide a solid theoretical basis and technical reference for the ...The durability and reliability of slab track structures are essential for the long-term safety and stable operation of high-speed railways.In order to provide a solid theoretical basis and technical reference for the advancement of high-speed railway quality,this paper comprehensively discusses design theories of slab track structures,service performance evolution and maintenance technologies,and reviews the innovation happening in the industry.On top of that,the damage evolution,fatigue features and durability of slab tracks,which are highly relevant to serviceability,are summarized,and the future research trend of slab track service behaviours is pointed out.In addition,this paper summarizes the rules of establishing standards for damage maintenance,typical solutions for repairing damage and methods of evaluating the maintenance outcomes that combine field tests and numerical simulations.It also envisions a future direction where advanced testing technologies would assist the evaluation of maintenance effects.展开更多
The Xiangyang East-Badong North section of the Zhengzhou-Wanzhou high-speed railway began its joint commissioning and testing on Feb.28.When put into service,Shennongjia and Badong will join China's high-speed rai...The Xiangyang East-Badong North section of the Zhengzhou-Wanzhou high-speed railway began its joint commissioning and testing on Feb.28.When put into service,Shennongjia and Badong will join China's high-speed railway network forthe first time.People in Wuhan will be able to reach Shennongjia within 2hours.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.62102032)the R&D Program of Beijing Municipal Education Commission(Grant No.KM202211417010).
文摘This paper describes the development and optimization plans for the China Railway Express(CR Express).As a new type of international land transport organization,CR Express has emerged with the continuous expansion of China toward European investment and trade,and in particular,has expanded with the continuous progress of the One Belt and One Road(OBOR)initiative.In addition to improving the service quality of CR Express,the operating costs must be reduced for developing“smart railways”that serve“smart cities”.We propose a dualobjective-based function mathematical optimization model;the satisfaction of the cargo owner is considered,and the timeliness,transportation capacity,and goods category constraints of CR Express transportation are designed.Moreover,we present the normalized equivalent method of the two-objective function of the model.Finally,a case study is conducted against the background of certain trains in the western corridor of CR Express to validate the effectiveness of the model and research methods proposed in this study.
文摘Railway is the backbone of Chinese transportation system,but its poor quality of services for passengers cause complains now and then.This study first analyzed the influencing factors of service quality on railway passenger,and its quality characteristics was also explained,and finally we proposed an evaluation system of service quality on railway passenger transport.Through the statistical analysis and processing of the basic information from survey data from railway station,trains and the official website of the ticket purchase,the evaluation score of question naire was converted into the score in evaluation index system,which was based on SERVQUAL model.Finally,the evaluation index system was applied to the field test,and all levels of indicators and the overall evaluation of railway passenger transport service quality was obtained.The relevant results show that the evaluation model of this study is concise and practical,and the method has certain practicability and promotion value,which is beneficial to the department of management supervision in railway transportation.
文摘Nowadays, because of its wide bandwidth and high communication capability, the optical fiber is more and more used for high data rate transmission of information in railway environments. Conventionally, only one service is sent over the fiber at a time. However, many different services can be simultaneously conveyed in railway stations such as passenger information service, cellular phone, Wi-Fi... The objective of the work proposed in this paper is to demonstrate the potential benefits of transmitting radio signals over fiber in a railway environment. The main idea is to exploit the full capacity of the fiber by transmitting multiple services using the same fiber. Since, different services are operating in different frequency bands; we propose a new multiplexing technique called Mode Group Diversity Multiplexing (MGDM) to ensure the transmission of multiple services using the same fiber, without additional infrastructure. There are numerous advantages of the proposed technique, e.g., faster and reliable data exchange, high resolution video surveillance capability, high data rate information exchange in railway stations. We present, in this paper, the physical characteristics of optical fibers, performance of MGDM multiplexing technique, and the influence of the laser excitation conditions at the entrance of the fiber on the performances of the system.
基金Projects(51478484,51308551,51678571)supported by the National Natural Science Foundation of ChinaProject(2016zzts063)supported by Fundamental Research Funds for the Central Universities,China
文摘Expansive soil is sensitive to dry and wet environment change. And the volume deformation and inflation pressure of expansive soil may induce to cause the deformation failure of roadbed or many other adverse effects. Aimed at a high-speed railway engineering practice in the newly built Yun-Gui high-speed railway expansive soil section in China, indoor vibration test on a full-scaled new cutting subgrade model is carried out. Based on the established track-subgrade-foundation of expansive soil system dynamic model test platform, dynamic behavior of new cutting subgrade structure under train loads coupling with extreme service environment(dry, raining, and groundwater level rising) is analyzed comparatively. The results show that the subgrade dynamic response is significantly influenced by service conditions and the dynamic response of subgrade gradually becomes stable with the increasing vibration times under various service environment conditions. The vertical dynamic soil stress is related with the depth in an approximate exponential function, and the curves of vertical dynamic soil stress present a "Z" shape distribution along transverse distance. The peak value of dynamic soil stress appears below the rail, and it increases more obviously near the roadbed surface. However, the peak value of dynamic soil stress is little affected outside 5.0 m of center line. The vibration velocity and acceleration are in a quadratic curve with an increase in depth, and the raining and groundwater level rising increase both the vibration velocity and the acceleration. The vertical deformations at different depths are differently affected by service environment in roadbed. The deformation of roadbed increases sharply when the water gets in the foundation of expansive soil, and more than 60% of the total deformation of roadbed occurs in expansive soil foundation. The laid waterproofing and drainage structure layer, which weakens the dynamic stress and improves the track regularity, presents a positive effect on the control deformation of roadbed surface. An improved empirical formula is then proposed to predict the dynamic stress of ballasted tracks subgrade of expansive soil.
文摘Rail transport has and continues to play a key role in the movement of goods and passengers in many countries around the world including Nigeria.However,while rail transport continues to enjoy relative importance in terms of investment,growth and contribution to the national economy in several countries,it has suffered and declined(in terms of modal share contribution which has led to decreased patronage)in Nigeria.However,there are new developments and investment on rail and some measures are being put in place to revive the Nigerian rail transport system.As these new developments and rehabilitations are going on,it will be imperative to know what the users/customers think as well,so that they are not left out because under normal circumstances,customers need transport services and not rail transport services.Therefore,if they were not satisfied with rail transport services they would simply turn to other modes of transport.As part of an on-going PhD research project,this paper focuses on the perceptions of Nigerian rail transport users/customers regarding the quality of rail services provided.Data was collected by the use of structured/semi-structured questionnaires,which were distributed,to the respondents.The study sample included 474 respondents between the age range of 20-70 out of which just 21(4.4%)have used rail transport;this low patronage figure is as a result of the long time neglect of the Nigerian rail transport system while 474(100%)of the correspondents use road transport daily which has led to an increasing pressure on road transport and infrastructures.Data was collected respectively from the following cities:Lagos,Warri,Ughelli and Benin.
基金supported by the National Key Research and Development Program of China(2021YFB2600405).
文摘In view of the problems of inconsistent data semantics,inconsistent data formats,and difficult data quality assurance between the railway engineering design phase and the construction and operation phase,as well as the difficulty in fully realizing the value of design results,this paper proposes a design and implementation scheme for a railway engineering collaborative design platform.The railway engineering collaborative design platform mainly includes functional modules such as metadata management,design collaboration,design delivery management,model component library,model rendering services,and Building Information Modeling(BIM)application services.Based on this,research is conducted on multi-disciplinary parameterized collaborative design technology for railway engineering,infrastructure data management and delivery technology,and design multi-source data fusion and application technology.The railway engineering collaborative design platform is compared with other railway design software to further validate its advantages and advanced features.The platform has been widely applied in multiple railway construction projects,greatly improving the design and project management efficiency.
文摘China’s railway network transported 1.004 billion tonnes of cargo in the third quarter of this year,marking a year-on-year increase of 3.8 percent and setting a new record for freight volume in a single quarter,official data showed on 20 October.China’s railway industry has been improving its transportation services and efficiency to support the high-quality development of the economy,according to China State Railway Group Co.,Ltd.
文摘With 2025 going to be a special year for China-Europe ties,2024 has provided many inspirations,from a milestone in the China-Europe train service to a new center for cooperation.THE Yiwu-Madrid freight railway route,the longest in the world,crisscrossing over 13,000 kilometers and covering eight countries,celebrated its 10th anniversary last November.
文摘Technological advancement in the field of trans- portation and communication has been happening at a faster pace in the past few decades. As the demand for high-speed transportation increases, the need for an improved seamless communication system to handle higher data traffic in a highly mobile environment becomes imperative. This paper proposes a novel scheme to enhance the quality of service in high-speed railway (HSR) communication environment using the concept of torch nodes (TNs) and adaptive measurement aggregation (AMA). The system was modeled using an object-oriented discrete event sim- ulator, and the performance was analyzed against the existing single-antenna scheme. The simulation results show that the proposed scheme with its minimal imple- mentation overhead can efficiently perform seamless han- dover with reduced handover failure and communication interruption probability.
基金funded by the National Natural Science Foundation of China[51778136 and 41972299].
文摘Purpose–This study aims to investigate the service performances of a new full-section asphalt concrete waterproof sealing structure(FSACWSS)for the high-speed railway subgrade through on-site tracking,monitoring and post-construction investigation.Design/methodology/approach–Based on the working state of the waterproof sealing structure,the main functional characteristics were analyzed,and a kind of roller-compacted high elastic modulus asphalt concrete(HEMAC)was designed and evaluated by several groups of laboratory tests.It is applied to an engineering test section,and the long-term performance monitoring and subgrade dynamic performance testing system were installed to track and monitor working performances of the test section and the adjacent contrast section with fiber-reinforced concrete.Findings–Results show that both the dynamic performance of the track structure and the subgrade in the test section meet the requirements of the specification limits.The water content in the subgrade of the test section is maintained at 8–18%,which is less affected by the weather.However,the water content in the subgrade bed of the contrast section is 10–35%,which fluctuates significantly with the weather.The heat absorption effect of asphalt concrete in the test section makes the temperature of the subgrade at the shoulder larger than that in the contrastive section.The monitoring value of the subgrade vertical deformation in the test section is slightly larger than that in the contrastive section,but all of them meet the limit requirements.The asphalt concrete in the test section is in good contact with the base,and there are no diseases such as looseness or spalling.Only a number of cracks are found at the joints of the base plates.However,there are more longitudinal and lateral cracks in the contrastive section,which seriously affects the waterproof and sealing effects.Besides,the asphalt concrete is easier to repair,featuring good maintainability.Originality/value–This research can provide a basis for popularization and application of the asphalt concrete waterproof sealing structure in high-speed railways.
文摘This is a review of high-speed train development in the sense of technology advances all over the world. Three generations of high-speed trains are classified according to their technical characteristics and maximum operating speed. Emphasis is given to the newly developed high-speed train in China, CRH380. The theoretical foundations and future development of CRH380 are briefly discussed.
基金This work has been supported in part by the National Natural Science Foundation of China(61671205)in part by the Shanghai Rising-Star Program(21QA1402700)in part by the open research fund of National Mobile Communications Research Laboratory,Southeast University(No.2020D02).
文摘In this paper,a beamforming scheme to improve the coverage in high-speed railway communication systems is investigated.A dedicated coverage model,where the coverage cell is an ellipse rather than the traditional circular or linear,is considered.Based on the elliptical coverage cell,an optimization problem for the beamforming design is formulated to maximize the percentage of railway coverage,subject to the constraints on equal expected designed propagation gain(the gain obtained by a combination of designed beam and propagation channel)on the elliptical curve,i.e.,the expectation of designed propagation gain on the elliptical curve are all equal.Considering that the coverage can be improved by increasing the minimum designed propagation gain on the railway,the problem can be recast to maximizing the equal expected designed propagation gain on the elliptical curve.Subsequently,a beamforming design with an improved β-fairness power allocation,where the optimization problem is formulated to maximize the minimum expected received power over time with the constraints on elliptical cell based beamforming and mobile service amount,is proposed to further improve the coverage.An alternating iteration algorithm is developed to find the optimal beamforming vector and the instantaneous transmit power.Through numerical results,it is found that the beamforming designed on the elliptical curve covers longer railway than beamforming designed on the railway directly,and the coverage of elliptical cell based beamforming can be increased with the eccentricity.In addition,beamforming with the improvedβ-fairness power allocation can further improve the railway coverage and mobile service amount simultaneously.Moreover,it is shown that the larger eccentricity of the ellipse with appropriately chosen BS location,the larger coverage distance.
文摘SUMMARIES OF TOP NEWS STORIES CHINA 358 km of New High-Speed Rail Introduced in First Four Months China put 581 km of new railway lines into service in the first four months of the year,including 358 km of high-speed railway。
基金support from the National Natural Science Foundation of China (Grant no.52022085).
文摘The durability and reliability of slab track structures are essential for the long-term safety and stable operation of high-speed railways.In order to provide a solid theoretical basis and technical reference for the advancement of high-speed railway quality,this paper comprehensively discusses design theories of slab track structures,service performance evolution and maintenance technologies,and reviews the innovation happening in the industry.On top of that,the damage evolution,fatigue features and durability of slab tracks,which are highly relevant to serviceability,are summarized,and the future research trend of slab track service behaviours is pointed out.In addition,this paper summarizes the rules of establishing standards for damage maintenance,typical solutions for repairing damage and methods of evaluating the maintenance outcomes that combine field tests and numerical simulations.It also envisions a future direction where advanced testing technologies would assist the evaluation of maintenance effects.
文摘The Xiangyang East-Badong North section of the Zhengzhou-Wanzhou high-speed railway began its joint commissioning and testing on Feb.28.When put into service,Shennongjia and Badong will join China's high-speed railway network forthe first time.People in Wuhan will be able to reach Shennongjia within 2hours.