There exists great potential of rural land consolidation in China due to the aggra- vated hollowed villages against the background of rapid rural-urban transformation. The pa- per aims to investigate the potential of ...There exists great potential of rural land consolidation in China due to the aggra- vated hollowed villages against the background of rapid rural-urban transformation. The pa- per aims to investigate the potential of rural land consolidation within four urbanization sce- narios: Complete urbanization, Semi-urbanization, Urbanization in batches and prospective urbanization in 2020. Research findings show that, (1) the potentials of rural land consolida- tion in complete and semi-urbanization are 809.89×104 hm2 and 699.19×104 hm2 respectively while rural consolidation rates are 50.70% and 43.77%. As for the urbanization in batches and urbanization in 2020, the potentials are 757.89×104 hm2 and 992.16×104 hm2. (2) Beside Tibet and Ningxia, rural consolidation rates in most provinces are between 40% and 60%, and the land increase rates are between 3% and 12%. Significant correlation between potential of rural land consolidation and the degree of hollowed villages is also found. (3) Evident differ- ences of potential of rural land consolidation exist across provinces. Rural consolidation rates in the East and Central provinces are higher than that in the West provinces. Villages in the developed areas have higher consolidation rates than those in the less developed areas, and villages in the plain areas tend to have higher consolidation rates than those in the moun- tainous areas.展开更多
In the future smart transportation system, reliable vehicle-to-infrastructure(V2 I) communication is very important to ensure vehicle driving safety and to improve vehicle driving efficiency. In this paper, V2 I chann...In the future smart transportation system, reliable vehicle-to-infrastructure(V2 I) communication is very important to ensure vehicle driving safety and to improve vehicle driving efficiency. In this paper, V2 I channel measurements at 5.92 GHz are conducted in typical urban and highway scenarios.The frequency and bandwidth of transmission, as well as the deployment of the RSU(roadside unit) and the OBU(on board unit), are selected by considering the recommendation proposed by 3 GPP TR 36.885. Then,based on the measured data, the key channel characteristic parameters of the V2 I channel are extracted,including path loss, root-mean-square delay spread,stationarity distance, and Doppler spread, etc. Also,the statistical characteristics of the parameters, including time-varying and Doppler characteristics, are investigated and characterized. The work in this paper helps researchers design technology and communication systems in similar scenarios.展开更多
The countries throughout the Belt and Road region account for more than 60%of the world’s population and half of the global economy.Future changes in this area will have significant influences on the global economic ...The countries throughout the Belt and Road region account for more than 60%of the world’s population and half of the global economy.Future changes in this area will have significant influences on the global economic growth,industrial structure and resource allocation.In this study,the proportion of the urban population to the total population and the gross domestic product were used to represent the levels of urbanization and economic development,respectively.The population,urbanization and economic levels of the Belt and Road countries for 2020-2050 were projected under the framework of the IPCC's shared socioeconomic pathways(SSPs),and the following conclusions are drawn.(1)The population,urbanization and economic levels in the Belt and Road region will likely increase under all five pathways.The population will increase by 2%-8%/10a during 2020-2050 and reach 5.0-6.0 billion in 2050.Meanwhile,the urbanization rate will increase by 1.4%-7.5%/10a and reach 49%-75%.The GDP will increase by 17%-34%/10a and reach 134-243 trillion USD.(2)Large differences will appear under different scenarios.The SSP1 and SSP5 pathways demonstrate relatively high urbanization and economic levels,but the population size is comparatively smaller;SSP3 shows the opposite trend.Meanwhile,the economy develops slowly under SSP4,but it has a relatively high urbanization level,while SSP2 exhibits an intermediate trend.(3)In 2050,the population will increase relative to 2016 in most countries,and population size in the fastest growing country in Central Asia and the Middle East countries will be more than double.Urbanization will develop rapidly in South Asia,West Asia and Central Asia,and will increase by more than 150%in the fastest growing countries.The economy will grow fastest in South Asia,Southeast Asia and West Asia,and increase by more than 10 times in some counties with rapid economic development.展开更多
基金The Key Project of National Natural Science Foundation of China, No.41130748.
文摘There exists great potential of rural land consolidation in China due to the aggra- vated hollowed villages against the background of rapid rural-urban transformation. The pa- per aims to investigate the potential of rural land consolidation within four urbanization sce- narios: Complete urbanization, Semi-urbanization, Urbanization in batches and prospective urbanization in 2020. Research findings show that, (1) the potentials of rural land consolida- tion in complete and semi-urbanization are 809.89×104 hm2 and 699.19×104 hm2 respectively while rural consolidation rates are 50.70% and 43.77%. As for the urbanization in batches and urbanization in 2020, the potentials are 757.89×104 hm2 and 992.16×104 hm2. (2) Beside Tibet and Ningxia, rural consolidation rates in most provinces are between 40% and 60%, and the land increase rates are between 3% and 12%. Significant correlation between potential of rural land consolidation and the degree of hollowed villages is also found. (3) Evident differ- ences of potential of rural land consolidation exist across provinces. Rural consolidation rates in the East and Central provinces are higher than that in the West provinces. Villages in the developed areas have higher consolidation rates than those in the less developed areas, and villages in the plain areas tend to have higher consolidation rates than those in the moun- tainous areas.
基金supported by National Natural Science Foundation of China (NSFC) under grant of 61931001。
文摘In the future smart transportation system, reliable vehicle-to-infrastructure(V2 I) communication is very important to ensure vehicle driving safety and to improve vehicle driving efficiency. In this paper, V2 I channel measurements at 5.92 GHz are conducted in typical urban and highway scenarios.The frequency and bandwidth of transmission, as well as the deployment of the RSU(roadside unit) and the OBU(on board unit), are selected by considering the recommendation proposed by 3 GPP TR 36.885. Then,based on the measured data, the key channel characteristic parameters of the V2 I channel are extracted,including path loss, root-mean-square delay spread,stationarity distance, and Doppler spread, etc. Also,the statistical characteristics of the parameters, including time-varying and Doppler characteristics, are investigated and characterized. The work in this paper helps researchers design technology and communication systems in similar scenarios.
文摘The countries throughout the Belt and Road region account for more than 60%of the world’s population and half of the global economy.Future changes in this area will have significant influences on the global economic growth,industrial structure and resource allocation.In this study,the proportion of the urban population to the total population and the gross domestic product were used to represent the levels of urbanization and economic development,respectively.The population,urbanization and economic levels of the Belt and Road countries for 2020-2050 were projected under the framework of the IPCC's shared socioeconomic pathways(SSPs),and the following conclusions are drawn.(1)The population,urbanization and economic levels in the Belt and Road region will likely increase under all five pathways.The population will increase by 2%-8%/10a during 2020-2050 and reach 5.0-6.0 billion in 2050.Meanwhile,the urbanization rate will increase by 1.4%-7.5%/10a and reach 49%-75%.The GDP will increase by 17%-34%/10a and reach 134-243 trillion USD.(2)Large differences will appear under different scenarios.The SSP1 and SSP5 pathways demonstrate relatively high urbanization and economic levels,but the population size is comparatively smaller;SSP3 shows the opposite trend.Meanwhile,the economy develops slowly under SSP4,but it has a relatively high urbanization level,while SSP2 exhibits an intermediate trend.(3)In 2050,the population will increase relative to 2016 in most countries,and population size in the fastest growing country in Central Asia and the Middle East countries will be more than double.Urbanization will develop rapidly in South Asia,West Asia and Central Asia,and will increase by more than 150%in the fastest growing countries.The economy will grow fastest in South Asia,Southeast Asia and West Asia,and increase by more than 10 times in some counties with rapid economic development.