There has been increasing interests in developing land use models for small urban areas for various planning applications such as air quality conformity analysis. The output of a land use model can serve as a major in...There has been increasing interests in developing land use models for small urban areas for various planning applications such as air quality conformity analysis. The output of a land use model can serve as a major input to a transportation model; conversely, transportation model output can provide a critical input to a land use model. The connection between the two models can be achieved by an accessibility measure. This paper presents an iterative approach to solving a regression-based land use model and a transportation model with combined trip distribution- assignment. A case study using data from a small urban area is presented to illustrate the application of the proposed modeling framework. Tests show that the procedures can converge, and the modeling framework can be a valuable tool for planners and decision-makers in evaluating land use policies and transportation investment strategies.展开更多
To address the challenges of supply-demand imbal-ance in rail transit and the complex passenger flow interactions among multiple hub stations under high-passenger-volume scenarios,this study proposes an optimized rail...To address the challenges of supply-demand imbal-ance in rail transit and the complex passenger flow interactions among multiple hub stations under high-passenger-volume scenarios,this study proposes an optimized rail transit scheduling method based on a flexible train formation strat-egy(FTFS).By constructing interaction parameters that characterize the coupling effects of high passenger flow across multiple hubs,a multiobjective optimization model is developed to minimize passenger waiting time at hub sta-tions and operational costs.An improved nondominated sorting genetic algorithm incorporating chaotic mapping and adaptive evolutionary parameters is designed for efficient so-lution optimization.This method overcomes the limitations of fixed train formations by supporting diversified modular unit detachment and reconnection,enabling dynamic capac-ity adjustment and efficient rolling stock circulation.A case study on Nanjing Metro Line 1 demonstrates that the FTFS reduces the average waiting time at hub stations by 47.2%,alleviates train congestion by approximately 18.6%,and re-duces the operational costs under low-demand scenarios by 44.8%.Pareto frontier analysis further reveals the trade-off mechanism between transport capacity elasticity and opera-tional costs.These findings validate the effectiveness of the flexible train formation model in mitigating platform conges-tion and enhancing passenger flow evacuation efficiency at transport hubs,providing multiobjective decision-making support for managing extreme passenger flow during holi-days and peak events.展开更多
A systematic analysis is performed to assess the current situation of transportation and tourism integration in 20 districts and counties located along National Highway 310(Gansu-Qinghai section),and optimization stra...A systematic analysis is performed to assess the current situation of transportation and tourism integration in 20 districts and counties located along National Highway 310(Gansu-Qinghai section),and optimization strategies are explored based on the findings of this analysis.The findings indicate a pressing necessity for further improvement in the practice of transportation and tourism integration in both Gansu and Qinghai provinces.Based on this foundation,a development framework for transportation and tourism integration has been established.This framework simulates a“fast-forward-slow-travel”system in which tourists commence their journey from the origin,traverse through core,secondary,and subsidiary tourist destinations,and ultimately reach the core,secondary,and subsidiary attractions.Furthermore,this study presents optimization recommendations for the integrated development of regional transportation and tourism along the designated route.These suggestions encompass the establishment and optimization of facilities and service points,the planning and design of tourism routes,the promotion of regional synergistic development,the construction of intelligent tourism,and the implementation of green tourism pathways.展开更多
Scientific development is an invaluable asset to a country.Policies and development modes should be carried out based on scientific findings not only in industry,but also in transportation infrastructure construction....Scientific development is an invaluable asset to a country.Policies and development modes should be carried out based on scientific findings not only in industry,but also in transportation infrastructure construction.Building an integrated transportation system,which is in line with the national requirements of China and supports sustainable socio-economic development,is a key strategic issue related to building a moderately prosperous society and achieving realistic goals of a medium-level developed country.Based on a systematic review of the advances in China's transportation infrastructure over the last 60 years,this paper explores the main drivers of transportation development,including national policy,transportation structure,investment efficiency,and technological innovation.Analysis shows that China's comprehensive transportation infrastructure construction since 1949 can be divided into five stages initiated by these drivers,which correspond to four transition modes:policy transition,structural transition,efficiency transition,and technology transition.The transition path of China's transportation development shows that the dominant factors have changed,and the interval for each transition has shortened.With the implementation of the '12th Five-Year Plan',China's transportation infrastructure construction is showing some new characteristics and facing a new development transition.Finally,this paper analyzes the trends in transportation development in China and concludes that technological innovation will be the main driving force to increase the transportation supply and service area in the future.展开更多
The Recommendations of the Central Committee of the Communist Party of China for Formulating the 15th Five-Year Plan for National Economic and Social Development,adopted at the fourth plenary session of the 2Oth Centr...The Recommendations of the Central Committee of the Communist Party of China for Formulating the 15th Five-Year Plan for National Economic and Social Development,adopted at the fourth plenary session of the 2Oth Central Committee of the Communist Party of China(CPC),proposes"improving the modern integrated transportation system,strengthening crossregional coordination and planning,promoting multi-modal integration,and improving transportation links and services in remote areas."This strategic directive by the CPC Central Committee,aimed at building a great country and advancing national rejuvenation through Chinese modernization,reflects a profound understanding of the significant role of transportation development.展开更多
Digitalization and decarbonization are projected to be two major trends in the coming decades.As the already widespread process of digitalization continues to progress,especially in energy and transportation systems,m...Digitalization and decarbonization are projected to be two major trends in the coming decades.As the already widespread process of digitalization continues to progress,especially in energy and transportation systems,massive data will be produced,and how these data could support and promote decarbonization has become a pressing concern.This paper presents a comprehensive review of digital technologies and their potential applications in low-carbon energy and transportation systems from the perspectives of infrastructure,common mechanisms and algorithms,and system-level impacts,as well as the application of digital technologies to coupled energy and transportation systems with electric vehicles.This paper also identifies corresponding challenges and future research directions,such as in the field of blockchain,digital twin,vehicle-to-grid,low-carbon computing,and data security and pri-vacy,especially in the context of integrated energy and transportation systems.展开更多
With the maturation of emerging information technologies(Internet of Things,cloud computing,and big data),distributed manufacturing has emerged as an important model for future manufacturing.3D printing,with its integ...With the maturation of emerging information technologies(Internet of Things,cloud computing,and big data),distributed manufacturing has emerged as an important model for future manufacturing.3D printing,with its integrated molding and design freedom,is a powerful catalyst for distributed manufacturing.This paper investigates the integrated production and transportation scheduling problem in distributed 3D printing.To solve this problem,we decompose the original problem into three sub-problems and design a multilevel optimization algorithm.We employ a genetic algorithm in the outer-level optimization to determine the optimal allocation of parts to machines.In the inner-level optimization,we utilize a simulated annealing algorithm to tackle the vehicle routing problem during the transportation stage followed by a local search algorithm to address the scheduling problem encountered during the production stage.Our algorithm is validated using real data from a 3D printing company,and the results show that our algorithm can obtain solutions that are the same as or better than those of Gurobi in a reasonable time for small-sized instances.Additionally,three types of initial methods are tested on large-sized instances to verify the efficiency of the proposed algorithm,and some interesting insights are also revealed and discussed.展开更多
The autumn precipitation over southwest China is one of the main causes of meteorological disasters. Using observed monthly station rainfall data and HadISST and NCEP/NCAR analysis data, the impacts of three types of ...The autumn precipitation over southwest China is one of the main causes of meteorological disasters. Using observed monthly station rainfall data and HadISST and NCEP/NCAR analysis data, the impacts of three types of El Ni<span style="white-space:normal;">ñ</span>o-Southern Oscillation (ENSO) events on the boreal autumn rainfall over southwest China were determined. Over southwest China, autumn rainfall constitutes > 20% of the total annual rainfall and a marked decline in autumn rainfall commenced around 1990. During La Ni<span style="white-space:normal;"><span style="white-space:normal;">ñ</span></span>a events, there is surplus (deficit) over the middle (northwest and southeast) of southwest China. In cnetral Pacific (CP) El Ni<span style="white-space:normal;">ñ</span>o events, the autumn rainfall anomaly shows a deficiency over China. The large-scale atmospheric circulation anomalies in the three ENSO categories also exhibit distinct characteristics. During CP El Ni<span style="white-space:normal;"><span style="white-space:normal;">ñ</span></span>o autumns, the pressure anomaly over the North Pacific Ocean displays a “<img src="Edit_8b97423a-3df3-4458-ad74-b4f2006dd708.png" alt="" />” structure, with a high-pressure anomaly over the Asian continent. An anomalous cyclone appears over the western North Pacific (WNP). In EP El Ni<span style="white-space:normal;"><span style="white-space:normal;">ñ</span></span>o autumns, the pressure anomaly over the North Pacific Ocean has a “<img src="Edit_3a7520ca-bfdd-4f81-a35c-4118a4616a5a.png" alt="" />” structure, with a low-pressure anomaly over the Asian continent. An anomalous anticyclone appears over the WNP and the 500-hPa anomalies are opposite to those of CP El Ni<span style="white-space:normal;"><span style="white-space:normal;"><span style="white-space:normal;">ñ</span></span></span>o events. During La Ni<span style="white-space:normal;"><span style="white-space:normal;">ñ</span></span>a autumns, the characteristics of circulation present<span style="font-family:;" "=""> </span><span style="font-family:Verdana;">the opposite structure to those of CP El Ni<span style="white-space:normal;"><span style="white-space:normal;"><span style="white-space:normal;">ñ</span></span></span>o events. This work is of certain significance for an in-depth understanding</span><span style="font-family:Verdana;"> of</span><span style="font-family:Verdana;"> the impacts of ENSO on the autumn precipitation over southwest China.</span>展开更多
Persistent severe rainfall(PSR)events,defined as regional-scale rainfall processes with daily precipitation no less than 50 mm for at least three consecutive days,frequently occur over South China(SC)and the middle-to...Persistent severe rainfall(PSR)events,defined as regional-scale rainfall processes with daily precipitation no less than 50 mm for at least three consecutive days,frequently occur over South China(SC)and the middle-to-lower Yangtze River Basin(MLYRB),with distinct dynamic mechanisms and moisture conditions in the two regions.Based on daily precipitation observations from China’s national meteorological stations and ERA5 reanalysis during 2012-21,this study investigates the spatiotemporal distribution of PSR events in SC and MLYRB and their associated three-dimensional circulation dynamics.The analysis integrates diagnostics of 200 hPa wave activity flux,perturbation streamfunction,500 hPa geopotential height,850 hPa wind fields,and integrated water vapor transport.Results show that PSR events in SC mainly occur during May-June,with rainfall centers over coastal and central Guangdong and Guangxi.In contrast,MLYRB events peak during June-July,with a banded rainfall pattern along the middle-to-lower Yangtze River.Dynamical diagnostics indicate that,in SC,sustained northwest-southeast propagation of 200 hPa disturbances,the southward shift of the 500 hPa trough,and steady subtropical high maintenance provide continuous dynamical support.Concurrently,strong and persistent 850 hPa southwesterlies and long-lasting moisture transport form favorable moisture conditions.In contrast,MLYRB events are marked by rapid phase transitions of 200 hPa streamfunction anomalies and northward-westward expansion of the 500 hPa subtropical high,triggering intense rainfall development.Simultaneously,abrupt enhancement of 850 hPa southwesterlies and rapid formation of a southwest moisture corridor ensure abundant and timely moisture supply,facilitating PSR onset.展开更多
The uncontrolled growth in urbanization and motorization generally contributes to an urban land use and transportation system that is socially, economically, and environmentally unsustainable. This paper uses Karachi ...The uncontrolled growth in urbanization and motorization generally contributes to an urban land use and transportation system that is socially, economically, and environmentally unsustainable. This paper uses Karachi as a case study, which is the largest urban and economic centre of Pakistan, passing through an uncontrolled phase of rapid urbanization and motorization. The paper first reviews research related to sustainable transportation systems to comprehend the concept of sustainable development and transportation. The paper then evaluates the existing transportation and infrastructure system, national transportation policies, and urban transportation projects to determine if the current paradigm is moving toward or away from sustainable transportation. Furthermore, the principles for sustainable urban transportation are developed to see what significance national transportation policies have given to urban transportation from a sustainable transportation point of view. Finally some strategies are suggested, adoption of which may lead to a sustainable urban development and transportation system in Karachi.展开更多
The rail transit system plays a crucial role in modern transportation.With the increasing demand for clean and green energy in the transport sector,its energy system is expected to achieve low-carbon and highly effici...The rail transit system plays a crucial role in modern transportation.With the increasing demand for clean and green energy in the transport sector,its energy system is expected to achieve low-carbon and highly efficient energy utilization in rail transit.However,the gradual development of the rail transport energy system has led to an increase in its complexity,and the rising difficulty of system assessment has faced the limitations of traditional assessment methods.Hence,it is essential to develop effective assessment methods.This paper begins by providing a systematic review of the development status of Reliability,Availability,Maintainability and Safety(RAMS)assessment and analyzing the shortcomings of traditional RAMS assessment technology in the context of rail transit energy systems.Subsequently,based on the four fundamental properties of RAMS,it summarizes the current state of key assessment technologies in the field of rail transit.Moreover,the paper delves into the challenges and potential solutions concerning the implementation of RAMS assessment technology for rail transit energy systems.Finally,the paper offers an outlook on the future development of RAMS assessment for rail transport energy systems.By comprehensively analyzing these aspects,the paper aims to contribute valuable insights into optimizing the rail transit energy system,promoting its sustainable and efficient operation in the context of clean and green energy utilization.展开更多
The expansion of e-commerce and the sharing economy has paved the way for crowdshipping as an innovative approach to addressing last-mile delivery challenges.Previous studies and implementations have predominantly con...The expansion of e-commerce and the sharing economy has paved the way for crowdshipping as an innovative approach to addressing last-mile delivery challenges.Previous studies and implementations have predominantly concentrated on private vehicle-based crowdshipping,which may lead to increased traffic congestion and emissions due to additional trips made specifically for deliveries.To circumvent these possible adverse effects,this paper explores a public transport(PT)-based crowdshipping concept as a complementary solution to the traditional parcel delivery systems.In this model,PT users leverage their routine journeys to perform delivery tasks.We propose a methodology that includes a parcel locker location model and a vehicle routing model to analyze the effect of PT-based crowdshipping.Notably,the parcel locker location model aids in planning a PT-based crowdshipping network and identifying obstacles to its development.A case study conducted in the central district of Copenhagen utilizing real-world data assesses the effects of PT-based crowdshipping.The findings suggest that PT-based crowdshipping can decrease the total kilometers traveled by vehicles,the overall working hours of drivers,and the number of vans required for last-mile deliveries,thereby alleviating urban traffic congestion and environmental pollution.Nevertheless,the growth of PT-based crowdshipping may be limited by the availability of crowdshippers,indicating that initiatives to increase the number of crowdshippers are essential.展开更多
文摘There has been increasing interests in developing land use models for small urban areas for various planning applications such as air quality conformity analysis. The output of a land use model can serve as a major input to a transportation model; conversely, transportation model output can provide a critical input to a land use model. The connection between the two models can be achieved by an accessibility measure. This paper presents an iterative approach to solving a regression-based land use model and a transportation model with combined trip distribution- assignment. A case study using data from a small urban area is presented to illustrate the application of the proposed modeling framework. Tests show that the procedures can converge, and the modeling framework can be a valuable tool for planners and decision-makers in evaluating land use policies and transportation investment strategies.
基金Key Project of the National Natural Science Foundation of China (No. 52432011)the National Natural Science Foundation of China (No. 524B2153)。
文摘To address the challenges of supply-demand imbal-ance in rail transit and the complex passenger flow interactions among multiple hub stations under high-passenger-volume scenarios,this study proposes an optimized rail transit scheduling method based on a flexible train formation strat-egy(FTFS).By constructing interaction parameters that characterize the coupling effects of high passenger flow across multiple hubs,a multiobjective optimization model is developed to minimize passenger waiting time at hub sta-tions and operational costs.An improved nondominated sorting genetic algorithm incorporating chaotic mapping and adaptive evolutionary parameters is designed for efficient so-lution optimization.This method overcomes the limitations of fixed train formations by supporting diversified modular unit detachment and reconnection,enabling dynamic capac-ity adjustment and efficient rolling stock circulation.A case study on Nanjing Metro Line 1 demonstrates that the FTFS reduces the average waiting time at hub stations by 47.2%,alleviates train congestion by approximately 18.6%,and re-duces the operational costs under low-demand scenarios by 44.8%.Pareto frontier analysis further reveals the trade-off mechanism between transport capacity elasticity and opera-tional costs.These findings validate the effectiveness of the flexible train formation model in mitigating platform conges-tion and enhancing passenger flow evacuation efficiency at transport hubs,providing multiobjective decision-making support for managing extreme passenger flow during holi-days and peak events.
文摘A systematic analysis is performed to assess the current situation of transportation and tourism integration in 20 districts and counties located along National Highway 310(Gansu-Qinghai section),and optimization strategies are explored based on the findings of this analysis.The findings indicate a pressing necessity for further improvement in the practice of transportation and tourism integration in both Gansu and Qinghai provinces.Based on this foundation,a development framework for transportation and tourism integration has been established.This framework simulates a“fast-forward-slow-travel”system in which tourists commence their journey from the origin,traverse through core,secondary,and subsidiary tourist destinations,and ultimately reach the core,secondary,and subsidiary attractions.Furthermore,this study presents optimization recommendations for the integrated development of regional transportation and tourism along the designated route.These suggestions encompass the establishment and optimization of facilities and service points,the planning and design of tourism routes,the promotion of regional synergistic development,the construction of intelligent tourism,and the implementation of green tourism pathways.
基金Under the auspices of National Natural Science Foundation of China(No.41171107,41001082)Programme of Bingwei Excellent Young Scientists of Institute of Geographic Sciences and Natural Resources Research,Chinese Academy of Sciences
文摘Scientific development is an invaluable asset to a country.Policies and development modes should be carried out based on scientific findings not only in industry,but also in transportation infrastructure construction.Building an integrated transportation system,which is in line with the national requirements of China and supports sustainable socio-economic development,is a key strategic issue related to building a moderately prosperous society and achieving realistic goals of a medium-level developed country.Based on a systematic review of the advances in China's transportation infrastructure over the last 60 years,this paper explores the main drivers of transportation development,including national policy,transportation structure,investment efficiency,and technological innovation.Analysis shows that China's comprehensive transportation infrastructure construction since 1949 can be divided into five stages initiated by these drivers,which correspond to four transition modes:policy transition,structural transition,efficiency transition,and technology transition.The transition path of China's transportation development shows that the dominant factors have changed,and the interval for each transition has shortened.With the implementation of the '12th Five-Year Plan',China's transportation infrastructure construction is showing some new characteristics and facing a new development transition.Finally,this paper analyzes the trends in transportation development in China and concludes that technological innovation will be the main driving force to increase the transportation supply and service area in the future.
文摘The Recommendations of the Central Committee of the Communist Party of China for Formulating the 15th Five-Year Plan for National Economic and Social Development,adopted at the fourth plenary session of the 2Oth Central Committee of the Communist Party of China(CPC),proposes"improving the modern integrated transportation system,strengthening crossregional coordination and planning,promoting multi-modal integration,and improving transportation links and services in remote areas."This strategic directive by the CPC Central Committee,aimed at building a great country and advancing national rejuvenation through Chinese modernization,reflects a profound understanding of the significant role of transportation development.
基金supports of Yuheng Zhang,Yifang Zheng,Yuke Zhou,Qiuyuan Ai,Xinjiang Chen,Jiayi Han,Ruiyang Jin,Yihang Jin,Jingyue Sang,Kaiyu Xie,Zhengrun Wu,Yuwen Zheng to this work.This work was supported in part by the National Natural Science Foundation of China under Grants 72271008,72131001,and 52277092.
文摘Digitalization and decarbonization are projected to be two major trends in the coming decades.As the already widespread process of digitalization continues to progress,especially in energy and transportation systems,massive data will be produced,and how these data could support and promote decarbonization has become a pressing concern.This paper presents a comprehensive review of digital technologies and their potential applications in low-carbon energy and transportation systems from the perspectives of infrastructure,common mechanisms and algorithms,and system-level impacts,as well as the application of digital technologies to coupled energy and transportation systems with electric vehicles.This paper also identifies corresponding challenges and future research directions,such as in the field of blockchain,digital twin,vehicle-to-grid,low-carbon computing,and data security and pri-vacy,especially in the context of integrated energy and transportation systems.
基金supported by the National Natural Science Foundation of China(72022018,72091210)Youth Innovation Promotion Association,Chinese Academy of Sciences(2021454).
文摘With the maturation of emerging information technologies(Internet of Things,cloud computing,and big data),distributed manufacturing has emerged as an important model for future manufacturing.3D printing,with its integrated molding and design freedom,is a powerful catalyst for distributed manufacturing.This paper investigates the integrated production and transportation scheduling problem in distributed 3D printing.To solve this problem,we decompose the original problem into three sub-problems and design a multilevel optimization algorithm.We employ a genetic algorithm in the outer-level optimization to determine the optimal allocation of parts to machines.In the inner-level optimization,we utilize a simulated annealing algorithm to tackle the vehicle routing problem during the transportation stage followed by a local search algorithm to address the scheduling problem encountered during the production stage.Our algorithm is validated using real data from a 3D printing company,and the results show that our algorithm can obtain solutions that are the same as or better than those of Gurobi in a reasonable time for small-sized instances.Additionally,three types of initial methods are tested on large-sized instances to verify the efficiency of the proposed algorithm,and some interesting insights are also revealed and discussed.
文摘The autumn precipitation over southwest China is one of the main causes of meteorological disasters. Using observed monthly station rainfall data and HadISST and NCEP/NCAR analysis data, the impacts of three types of El Ni<span style="white-space:normal;">ñ</span>o-Southern Oscillation (ENSO) events on the boreal autumn rainfall over southwest China were determined. Over southwest China, autumn rainfall constitutes > 20% of the total annual rainfall and a marked decline in autumn rainfall commenced around 1990. During La Ni<span style="white-space:normal;"><span style="white-space:normal;">ñ</span></span>a events, there is surplus (deficit) over the middle (northwest and southeast) of southwest China. In cnetral Pacific (CP) El Ni<span style="white-space:normal;">ñ</span>o events, the autumn rainfall anomaly shows a deficiency over China. The large-scale atmospheric circulation anomalies in the three ENSO categories also exhibit distinct characteristics. During CP El Ni<span style="white-space:normal;"><span style="white-space:normal;">ñ</span></span>o autumns, the pressure anomaly over the North Pacific Ocean displays a “<img src="Edit_8b97423a-3df3-4458-ad74-b4f2006dd708.png" alt="" />” structure, with a high-pressure anomaly over the Asian continent. An anomalous cyclone appears over the western North Pacific (WNP). In EP El Ni<span style="white-space:normal;"><span style="white-space:normal;">ñ</span></span>o autumns, the pressure anomaly over the North Pacific Ocean has a “<img src="Edit_3a7520ca-bfdd-4f81-a35c-4118a4616a5a.png" alt="" />” structure, with a low-pressure anomaly over the Asian continent. An anomalous anticyclone appears over the WNP and the 500-hPa anomalies are opposite to those of CP El Ni<span style="white-space:normal;"><span style="white-space:normal;"><span style="white-space:normal;">ñ</span></span></span>o events. During La Ni<span style="white-space:normal;"><span style="white-space:normal;">ñ</span></span>a autumns, the characteristics of circulation present<span style="font-family:;" "=""> </span><span style="font-family:Verdana;">the opposite structure to those of CP El Ni<span style="white-space:normal;"><span style="white-space:normal;"><span style="white-space:normal;">ñ</span></span></span>o events. This work is of certain significance for an in-depth understanding</span><span style="font-family:Verdana;"> of</span><span style="font-family:Verdana;"> the impacts of ENSO on the autumn precipitation over southwest China.</span>
基金funded by the Science and Technology Development Fund of Macao Special Administrative Region(Grant No.0009/2024/RIB1)the Guangdong Major Project of Basic and Applied Basic Research(Grant No.2020B0301030004).
文摘Persistent severe rainfall(PSR)events,defined as regional-scale rainfall processes with daily precipitation no less than 50 mm for at least three consecutive days,frequently occur over South China(SC)and the middle-to-lower Yangtze River Basin(MLYRB),with distinct dynamic mechanisms and moisture conditions in the two regions.Based on daily precipitation observations from China’s national meteorological stations and ERA5 reanalysis during 2012-21,this study investigates the spatiotemporal distribution of PSR events in SC and MLYRB and their associated three-dimensional circulation dynamics.The analysis integrates diagnostics of 200 hPa wave activity flux,perturbation streamfunction,500 hPa geopotential height,850 hPa wind fields,and integrated water vapor transport.Results show that PSR events in SC mainly occur during May-June,with rainfall centers over coastal and central Guangdong and Guangxi.In contrast,MLYRB events peak during June-July,with a banded rainfall pattern along the middle-to-lower Yangtze River.Dynamical diagnostics indicate that,in SC,sustained northwest-southeast propagation of 200 hPa disturbances,the southward shift of the 500 hPa trough,and steady subtropical high maintenance provide continuous dynamical support.Concurrently,strong and persistent 850 hPa southwesterlies and long-lasting moisture transport form favorable moisture conditions.In contrast,MLYRB events are marked by rapid phase transitions of 200 hPa streamfunction anomalies and northward-westward expansion of the 500 hPa subtropical high,triggering intense rainfall development.Simultaneously,abrupt enhancement of 850 hPa southwesterlies and rapid formation of a southwest moisture corridor ensure abundant and timely moisture supply,facilitating PSR onset.
基金Supported by the International Corporation Project
文摘The uncontrolled growth in urbanization and motorization generally contributes to an urban land use and transportation system that is socially, economically, and environmentally unsustainable. This paper uses Karachi as a case study, which is the largest urban and economic centre of Pakistan, passing through an uncontrolled phase of rapid urbanization and motorization. The paper first reviews research related to sustainable transportation systems to comprehend the concept of sustainable development and transportation. The paper then evaluates the existing transportation and infrastructure system, national transportation policies, and urban transportation projects to determine if the current paradigm is moving toward or away from sustainable transportation. Furthermore, the principles for sustainable urban transportation are developed to see what significance national transportation policies have given to urban transportation from a sustainable transportation point of view. Finally some strategies are suggested, adoption of which may lead to a sustainable urban development and transportation system in Karachi.
基金supported by the National Key R&D Plan Foundation of China(Grant No.2021YFB2601300)Supported by the Fundamental Research Funds for the Central Universities(Grant No.2023JC007).
文摘The rail transit system plays a crucial role in modern transportation.With the increasing demand for clean and green energy in the transport sector,its energy system is expected to achieve low-carbon and highly efficient energy utilization in rail transit.However,the gradual development of the rail transport energy system has led to an increase in its complexity,and the rising difficulty of system assessment has faced the limitations of traditional assessment methods.Hence,it is essential to develop effective assessment methods.This paper begins by providing a systematic review of the development status of Reliability,Availability,Maintainability and Safety(RAMS)assessment and analyzing the shortcomings of traditional RAMS assessment technology in the context of rail transit energy systems.Subsequently,based on the four fundamental properties of RAMS,it summarizes the current state of key assessment technologies in the field of rail transit.Moreover,the paper delves into the challenges and potential solutions concerning the implementation of RAMS assessment technology for rail transit energy systems.Finally,the paper offers an outlook on the future development of RAMS assessment for rail transport energy systems.By comprehensively analyzing these aspects,the paper aims to contribute valuable insights into optimizing the rail transit energy system,promoting its sustainable and efficient operation in the context of clean and green energy utilization.
基金supported by the China Scholarship Council(202107940012).
文摘The expansion of e-commerce and the sharing economy has paved the way for crowdshipping as an innovative approach to addressing last-mile delivery challenges.Previous studies and implementations have predominantly concentrated on private vehicle-based crowdshipping,which may lead to increased traffic congestion and emissions due to additional trips made specifically for deliveries.To circumvent these possible adverse effects,this paper explores a public transport(PT)-based crowdshipping concept as a complementary solution to the traditional parcel delivery systems.In this model,PT users leverage their routine journeys to perform delivery tasks.We propose a methodology that includes a parcel locker location model and a vehicle routing model to analyze the effect of PT-based crowdshipping.Notably,the parcel locker location model aids in planning a PT-based crowdshipping network and identifying obstacles to its development.A case study conducted in the central district of Copenhagen utilizing real-world data assesses the effects of PT-based crowdshipping.The findings suggest that PT-based crowdshipping can decrease the total kilometers traveled by vehicles,the overall working hours of drivers,and the number of vans required for last-mile deliveries,thereby alleviating urban traffic congestion and environmental pollution.Nevertheless,the growth of PT-based crowdshipping may be limited by the availability of crowdshippers,indicating that initiatives to increase the number of crowdshippers are essential.
