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
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 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
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 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
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 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 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.