In order to study the nodes importance and its evolution process of the railway network of SREB (Silk Road Economic Belt), we construct the network (RNSREB) based on Graph Theory, which focuses on the time intervals a...In order to study the nodes importance and its evolution process of the railway network of SREB (Silk Road Economic Belt), we construct the network (RNSREB) based on Graph Theory, which focuses on the time intervals according to actually railway network, railway project under construction and the national railway network of medium-and long-term plan. The algorithms for vital nodes evaluation are analyzed, the evaluation method on nodes importance of RNSREB is proposed, the quantized values of each node are calculated with Pajek, and TOP20 core nodes of the network with different coefficients and time intervals are determined respectively. Then the evolution process of TOP20 critical nodes with 4 periods is contrasted and analyzed. It is indicated that some vital nodes newly discovered (Geermu, Maduo, Ruoqiang) should be concerned.展开更多
A model is proposed to describe the passengers’route choice behaviors in urban railway traffic with stochastic link capacity degradation by considering two types of demand,sensitive and insensitive passenger.The inse...A model is proposed to describe the passengers’route choice behaviors in urban railway traffic with stochastic link capacity degradation by considering two types of demand,sensitive and insensitive passenger.The insensitive passengers choose their route without paying much attention to congestion.To the contrary,sensitive passengers who consider route congestion choose travel route based on generalized cost.An equilibrium state is given by variational inequalities in terms of travel generalized cost,which is represented by the combinations of mean and variance of total travel time.The diagonalization algorithm is given to solve this programming.Results show that insensitive passengers have large effects on the path choice than sensitive ones,especially for the larger demand.展开更多
Financing of the African Integrated High-Speed Railway Network (AIHSRN) through Standard Gauge Railway (SGR) Projects is very expensive. As a result, most of the African countries seek financial supports from the Inte...Financing of the African Integrated High-Speed Railway Network (AIHSRN) through Standard Gauge Railway (SGR) Projects is very expensive. As a result, most of the African countries seek financial supports from the International Financial Institutions (IFIs). However, conditions provided by the IFIs through the Performance Standards (PS) of the International Financial Corporation (IFC) increase cost of the projects and thus, it becomes a burden to most of the African countries. This study aimed to explore the causes of IFC-PS through the SGR Projects that escalate costs and how to address them. The Tanzania SGR Lot 1 Project that covered 205 km from Dar es Salaam to Morogoro was selected as a case study. The methods used for data collection involved literature review, focus group discussions and interviews. The results and findings show a gap between the IFC-PS and the National Laws and Regulations that escalates costs of the projects if funds from the IFIs were to be secured. To bridge the gap, it is recommended that the African countries should engage into negotiations with the IFIs to agree to waive IFC-PS conditions that escalate costs provided they are adequately covered in the national laws and regulations;engagement of locally established national and regional financial institutions;and the responsible government institutions in the African countries should sit together for assessment and review of the IFC-PS against the national laws and regulations.展开更多
With the significant development of liquefied natural gas(LNG)rail transport,the railway system is increasingly more closely connected with the integrated electricity-natural gas system(IEGS).To coordinate the economi...With the significant development of liquefied natural gas(LNG)rail transport,the railway system is increasingly more closely connected with the integrated electricity-natural gas system(IEGS).To coordinate the economic operations of the two systems,this paper innovatively proposes a coordinated dispatch model of IEGS with LNG infrastructures and a freight railway network with LNG transport.First,an operational scheduling model of the railway network,considering energy consumption,is put forward for both LNG transmission and ordinary freight transport.Then,the coordinated dispatch problem of IEGS and the railway network is formulated into a mixed-integer linear programming model via the big M method and a modified incremental linearization approach.Finally,a bi-level optimization algorithm based on generalized benders decomposition(GBD)is presented to solve the coordinated dispatch problem due to the restrictions on exchanging private information.Case studies demonstrate the effectiveness of the proposed model and algorithm as well as the potential benefit for wind power accommodation.展开更多
The integrated aviation and High-Speed Railway(HSR)transportation system plays a vital role for today’s inter-city transportation services.However,an increasing number of unexpected disruptions(such as operation fail...The integrated aviation and High-Speed Railway(HSR)transportation system plays a vital role for today’s inter-city transportation services.However,an increasing number of unexpected disruptions(such as operation failures,natural disasters,or intentional attacks)pose a considerable threat to the normal operation of the system,especially on ground transfer,leading to the extensive research on its vulnerability.Previous approaches mainly focus on interruptions within a single transportation mode,neglecting the role of ground transfer which serves as a coupled connection between aviation and High-Speed Railway.This paper proposes a network-based framework for evaluating the vulnerability of the Chinese Coupled Aviation and High-Speed Railway(CAHSR)network from the viewpoint of ground transfer interruption.Taking the end-to-end travel time and passenger flow information into consideration as an evaluation measure and analyzing from the perspective of urban agglomerations,an adaptive method is developed to identify the critical cities and further investigate their failure impacts on the geographic distribution of vulnerability.In addition,the proposed model explores variations of vulnerability under different failure time intervals.Based on the empirical study,some major conclusions are highlighted as follows:(A)Only a few cities show significant impacts on the network’s vulnerability when ground transfer interruptions occurred.(B)The distribution of vulnerability is not proportional to the distance between failure city and influenced city.(C)The vulnerability is more serious in the morning and evening when the ground transfer is disconnected.Our findings may provide new insights for maintenance and optimization of the CAHSR network and other real-world transportation networks.展开更多
In the functional properties of complex networks, modules play a central role. In this paper, we propose a new method to detect and describe the modular structures of weighted networks. In order to test the proposed m...In the functional properties of complex networks, modules play a central role. In this paper, we propose a new method to detect and describe the modular structures of weighted networks. In order to test the proposed method, as an example, we use our method to analyse the structural properties of the Chinese railway network. Here, the stations are regarded as the nodes and the track sections are regarded as the links. Rigorous analysis of the existing data shows that using the proposed algorithm, the nodes of network can be classified naturally. Moreover, there are several core nodes in each module. Remarkably, we introduce the correlation function Grs, and use it to distinguish the different modules in weighted networks.展开更多
Consulting concepts of business process reengineering of modem enterprises and according to networked industry characteristics of railway, this article analyzes restructuring experience modes of foreign railway, probe...Consulting concepts of business process reengineering of modem enterprises and according to networked industry characteristics of railway, this article analyzes restructuring experience modes of foreign railway, probes into the trend of China railway restructure, and makes it clear that railway should set up modem enterprise systems by focusing on transport as major trade. As a result, the railway informalization system shall be guided by marketing, aiming at improving the operation efficiency and management benefits, having priority in passenger and goods marketing system development. Central control and safeguarding systems should be emphasized in construction and railway business management systems shall be broueht about.展开更多
The paper summarizes the development of mobile communication of domestic and foreign railways,and proposes the priorities for tackling key technological problems of railway 5G private network according to the technica...The paper summarizes the development of mobile communication of domestic and foreign railways,and proposes the priorities for tackling key technological problems of railway 5G private network according to the technical routes of railway next-generation mobile communication determined by China State Railway Group Co.,Ltd.From the aspects of work objectives,principles,technical routes and innovative working methods,the paper elaborates the ideas of railway 5G scientific and technological research,puts forward the contents and plans of scientific and technological research on railway 5G private network,systematically organizes the achievements in the scientific and technological research stage of railway 5G private network,and sets forth the key contents of next-step scientific and technological research.展开更多
Up till now,no systematic studies on railway route selection in urban areas,HSR route selection in particular,have been taken in China.Based on the Shenzhen Railway Terminal Project and the Shenzhen-Shanwei Railway Pr...Up till now,no systematic studies on railway route selection in urban areas,HSR route selection in particular,have been taken in China.Based on the Shenzhen Railway Terminal Project and the Shenzhen-Shanwei Railway Project,research on HSR route selection in complicated urban areas has been conducted.An optimal route selection plan is determined after studying the local geological and environmental conditions and the complexity of tunnel construction.The research concludes that there are four major concerns in HSR route selection:the match between the new route and the urban planning,the potential economic return for the massive investment,the likely impacts of land expropriation on social stability,and the best synthesis of multiple controlling factors to meet the HSR standard.Moreover,six principles should be followed in railway route selection in complicated urban areas:the new route should be in alignment with the railway deployment;the route should align with the existing passage as much as possible;extensive analysis and in-depth demonstrations should be done to find the most appropriate combination of open and hidden excavation in tunnel construction;geological conditions and tunnel construction complexities are among the priorities;environmental sensitive sites and environmental vibration noise should be avoided as much as possible;special attention should be paid to the relocation of the power supply,television and communication facilities and the rearrangement of tubes and wires.展开更多
This paper discusses the control strategy for energy management in railway transit network with wayside(substation)supercapacitor(SC)energy storage system(ESS).Firstly,the structure of the wayside energy storage syste...This paper discusses the control strategy for energy management in railway transit network with wayside(substation)supercapacitor(SC)energy storage system(ESS).Firstly,the structure of the wayside energy storage system is introduced.Secondly,the model of energy storage system is built and the control strategy is described.Thirdly,in order to estimate the required energy storage system,a useful method is proposed to predict the instantaneous regenerative energy magnitude which is delivered to each substation.Finally,the ESS configuration for each substation is determined.A simplified mathematical model of the whole metro network is established and the main features of the control strategy are developed.Numerical simulations show the efficacy of suggested control strategy and the energy saving obtained for railway transit network.展开更多
Recently,electric railways have experienced a rapid development causing an increasing power demand.Due to the flexible installation available at trackside land along railways,photovoltaic(PV)generation is suggested as...Recently,electric railways have experienced a rapid development causing an increasing power demand.Due to the flexible installation available at trackside land along railways,photovoltaic(PV)generation is suggested as an extension to the traction power supply system(TPSS)in railways.First,this paper proposes a three-phase integrated configuration for PV generation connected to a two-phase traction network and the on-site consumption of solar resources alongside railways.In this configuration,another inverse V/V transformer is used to maintain a balanced three-phase low voltage(LV)AC bus from a two-phase traction network.It is more convenient for accessing PV generation units.Then,in order to mitigate the negative sequence currents caused by electric trains,an individual phase current(IPC)control strategy for PV converters is developed for power quality improvement.It can not only supply the locomotive with asymmetrical currents,but also provide feedback to the grid through symmetrical currents.All the implementation and calculations are conducted in the three-phase stationary reference frame without any sequence extracting and power compensations.Finally,simulation results are presented to validate the effectiveness of the proposed IPC control strategy.展开更多
文摘In order to study the nodes importance and its evolution process of the railway network of SREB (Silk Road Economic Belt), we construct the network (RNSREB) based on Graph Theory, which focuses on the time intervals according to actually railway network, railway project under construction and the national railway network of medium-and long-term plan. The algorithms for vital nodes evaluation are analyzed, the evaluation method on nodes importance of RNSREB is proposed, the quantized values of each node are calculated with Pajek, and TOP20 core nodes of the network with different coefficients and time intervals are determined respectively. Then the evolution process of TOP20 critical nodes with 4 periods is contrasted and analyzed. It is indicated that some vital nodes newly discovered (Geermu, Maduo, Ruoqiang) should be concerned.
基金Project(71525002) supported by China National Funds for Distinguished Young ScientistsProjects(71271023,71210001) supported by the National Natural Science Foundation of ChinaProject(RCS2015ZZ003) supported by the Research Foundation of State Key Laboratory of Rail Traffic Control and Safety,Beijing Jiaotong University,China
文摘A model is proposed to describe the passengers’route choice behaviors in urban railway traffic with stochastic link capacity degradation by considering two types of demand,sensitive and insensitive passenger.The insensitive passengers choose their route without paying much attention to congestion.To the contrary,sensitive passengers who consider route congestion choose travel route based on generalized cost.An equilibrium state is given by variational inequalities in terms of travel generalized cost,which is represented by the combinations of mean and variance of total travel time.The diagonalization algorithm is given to solve this programming.Results show that insensitive passengers have large effects on the path choice than sensitive ones,especially for the larger demand.
文摘Financing of the African Integrated High-Speed Railway Network (AIHSRN) through Standard Gauge Railway (SGR) Projects is very expensive. As a result, most of the African countries seek financial supports from the International Financial Institutions (IFIs). However, conditions provided by the IFIs through the Performance Standards (PS) of the International Financial Corporation (IFC) increase cost of the projects and thus, it becomes a burden to most of the African countries. This study aimed to explore the causes of IFC-PS through the SGR Projects that escalate costs and how to address them. The Tanzania SGR Lot 1 Project that covered 205 km from Dar es Salaam to Morogoro was selected as a case study. The methods used for data collection involved literature review, focus group discussions and interviews. The results and findings show a gap between the IFC-PS and the National Laws and Regulations that escalates costs of the projects if funds from the IFIs were to be secured. To bridge the gap, it is recommended that the African countries should engage into negotiations with the IFIs to agree to waive IFC-PS conditions that escalate costs provided they are adequately covered in the national laws and regulations;engagement of locally established national and regional financial institutions;and the responsible government institutions in the African countries should sit together for assessment and review of the IFC-PS against the national laws and regulations.
基金This work was supported by the National Key Research and Development Program of China(2016YFB0901900)the National Natural Science Foundation of China(51637008).
文摘With the significant development of liquefied natural gas(LNG)rail transport,the railway system is increasingly more closely connected with the integrated electricity-natural gas system(IEGS).To coordinate the economic operations of the two systems,this paper innovatively proposes a coordinated dispatch model of IEGS with LNG infrastructures and a freight railway network with LNG transport.First,an operational scheduling model of the railway network,considering energy consumption,is put forward for both LNG transmission and ordinary freight transport.Then,the coordinated dispatch problem of IEGS and the railway network is formulated into a mixed-integer linear programming model via the big M method and a modified incremental linearization approach.Finally,a bi-level optimization algorithm based on generalized benders decomposition(GBD)is presented to solve the coordinated dispatch problem due to the restrictions on exchanging private information.Case studies demonstrate the effectiveness of the proposed model and algorithm as well as the potential benefit for wind power accommodation.
基金co-supported by the National Key Research and Development Program of China(No.2019YFF0301400)the National Natural Science Foundation of China(Nos.61961146005,62088101)supported by Beijing Postdoctoral Research Foundation,China(No.2021-ZZ-153).
文摘The integrated aviation and High-Speed Railway(HSR)transportation system plays a vital role for today’s inter-city transportation services.However,an increasing number of unexpected disruptions(such as operation failures,natural disasters,or intentional attacks)pose a considerable threat to the normal operation of the system,especially on ground transfer,leading to the extensive research on its vulnerability.Previous approaches mainly focus on interruptions within a single transportation mode,neglecting the role of ground transfer which serves as a coupled connection between aviation and High-Speed Railway.This paper proposes a network-based framework for evaluating the vulnerability of the Chinese Coupled Aviation and High-Speed Railway(CAHSR)network from the viewpoint of ground transfer interruption.Taking the end-to-end travel time and passenger flow information into consideration as an evaluation measure and analyzing from the perspective of urban agglomerations,an adaptive method is developed to identify the critical cities and further investigate their failure impacts on the geographic distribution of vulnerability.In addition,the proposed model explores variations of vulnerability under different failure time intervals.Based on the empirical study,some major conclusions are highlighted as follows:(A)Only a few cities show significant impacts on the network’s vulnerability when ground transfer interruptions occurred.(B)The distribution of vulnerability is not proportional to the distance between failure city and influenced city.(C)The vulnerability is more serious in the morning and evening when the ground transfer is disconnected.Our findings may provide new insights for maintenance and optimization of the CAHSR network and other real-world transportation networks.
文摘In the functional properties of complex networks, modules play a central role. In this paper, we propose a new method to detect and describe the modular structures of weighted networks. In order to test the proposed method, as an example, we use our method to analyse the structural properties of the Chinese railway network. Here, the stations are regarded as the nodes and the track sections are regarded as the links. Rigorous analysis of the existing data shows that using the proposed algorithm, the nodes of network can be classified naturally. Moreover, there are several core nodes in each module. Remarkably, we introduce the correlation function Grs, and use it to distinguish the different modules in weighted networks.
文摘Consulting concepts of business process reengineering of modem enterprises and according to networked industry characteristics of railway, this article analyzes restructuring experience modes of foreign railway, probes into the trend of China railway restructure, and makes it clear that railway should set up modem enterprise systems by focusing on transport as major trade. As a result, the railway informalization system shall be guided by marketing, aiming at improving the operation efficiency and management benefits, having priority in passenger and goods marketing system development. Central control and safeguarding systems should be emphasized in construction and railway business management systems shall be broueht about.
文摘The paper summarizes the development of mobile communication of domestic and foreign railways,and proposes the priorities for tackling key technological problems of railway 5G private network according to the technical routes of railway next-generation mobile communication determined by China State Railway Group Co.,Ltd.From the aspects of work objectives,principles,technical routes and innovative working methods,the paper elaborates the ideas of railway 5G scientific and technological research,puts forward the contents and plans of scientific and technological research on railway 5G private network,systematically organizes the achievements in the scientific and technological research stage of railway 5G private network,and sets forth the key contents of next-step scientific and technological research.
文摘Up till now,no systematic studies on railway route selection in urban areas,HSR route selection in particular,have been taken in China.Based on the Shenzhen Railway Terminal Project and the Shenzhen-Shanwei Railway Project,research on HSR route selection in complicated urban areas has been conducted.An optimal route selection plan is determined after studying the local geological and environmental conditions and the complexity of tunnel construction.The research concludes that there are four major concerns in HSR route selection:the match between the new route and the urban planning,the potential economic return for the massive investment,the likely impacts of land expropriation on social stability,and the best synthesis of multiple controlling factors to meet the HSR standard.Moreover,six principles should be followed in railway route selection in complicated urban areas:the new route should be in alignment with the railway deployment;the route should align with the existing passage as much as possible;extensive analysis and in-depth demonstrations should be done to find the most appropriate combination of open and hidden excavation in tunnel construction;geological conditions and tunnel construction complexities are among the priorities;environmental sensitive sites and environmental vibration noise should be avoided as much as possible;special attention should be paid to the relocation of the power supply,television and communication facilities and the rearrangement of tubes and wires.
文摘This paper discusses the control strategy for energy management in railway transit network with wayside(substation)supercapacitor(SC)energy storage system(ESS).Firstly,the structure of the wayside energy storage system is introduced.Secondly,the model of energy storage system is built and the control strategy is described.Thirdly,in order to estimate the required energy storage system,a useful method is proposed to predict the instantaneous regenerative energy magnitude which is delivered to each substation.Finally,the ESS configuration for each substation is determined.A simplified mathematical model of the whole metro network is established and the main features of the control strategy are developed.Numerical simulations show the efficacy of suggested control strategy and the energy saving obtained for railway transit network.
基金supported in part by the National Natural Science Foundation of China(51807182)。
文摘Recently,electric railways have experienced a rapid development causing an increasing power demand.Due to the flexible installation available at trackside land along railways,photovoltaic(PV)generation is suggested as an extension to the traction power supply system(TPSS)in railways.First,this paper proposes a three-phase integrated configuration for PV generation connected to a two-phase traction network and the on-site consumption of solar resources alongside railways.In this configuration,another inverse V/V transformer is used to maintain a balanced three-phase low voltage(LV)AC bus from a two-phase traction network.It is more convenient for accessing PV generation units.Then,in order to mitigate the negative sequence currents caused by electric trains,an individual phase current(IPC)control strategy for PV converters is developed for power quality improvement.It can not only supply the locomotive with asymmetrical currents,but also provide feedback to the grid through symmetrical currents.All the implementation and calculations are conducted in the three-phase stationary reference frame without any sequence extracting and power compensations.Finally,simulation results are presented to validate the effectiveness of the proposed IPC control strategy.
