As two rising great powers, China and India have undergone similar development processes, but they also exhibit significant differences in development paths and patterns. The significant differences in political syste...As two rising great powers, China and India have undergone similar development processes, but they also exhibit significant differences in development paths and patterns. The significant differences in political systems, economic systems, and developmental environment between the two countries have attracted great attention from scholars. This research focuses on the regional differences and spatial evolution processes in urbanization and urban systems between the two countries from a geographical perspective. Based on the demographic censuses of both countries and the urban population data from the United Nations, this paper systematically compared and analyzed the spatial characteristics of urbanization and urban systems in China and India using various methods including spatial analysis, parameter estimation, and nonparametric estimation. The results indicate that:(1) Since the 1990 s, the regional differences in urbanization in China have transformed from south-north differences to coastal-inland differences, whereas the north-south differences in India have been stable.(2) In recent years, the correlation between population density and urbanization rate kept increasing in China, while such correlation has been decreasing in India.(3) The economic reform posed significantly different effects on the spatial evolution of the urban systems in the two countries. The economic reform changed the major driving force for urban development in China from geographical and historical factors to the spatial structure of the economic system. However, in India, the driving forces for urban development have always been geographical and historical factors, and the economic reform even decreased the effect of the spatial structure of the economic system on urban development.展开更多
The purpose of this research is to investigate the socio-economic development mechanism of China’s urban system in terms of spatial structure and its change. Totally 246 cities from 340 designated cities in 1985, and...The purpose of this research is to investigate the socio-economic development mechanism of China’s urban system in terms of spatial structure and its change. Totally 246 cities from 340 designated cities in 1985, and 488 from 640 designated cities in 1995 are selected as sample cities. And 22 attributes concerning urban features are analyzed to clarify the socio-economic characteristics and their changes in the urban system. Finally, the primary development factors are verified with the relationship of spatial structure and socio-economic characteristics. In conclusion, the socio-economic changes occurred more extremely than spatial structure changes. Furthermore, foreign investment be- came a major power for the development of China’s urban system in the period of 1985–1995.展开更多
Urban system is the spatial reflection of the inner-deep social economic movement. New economic circumstances not only make the evolution of urban system present one brand-new landscape, but also put forward a new sub...Urban system is the spatial reflection of the inner-deep social economic movement. New economic circumstances not only make the evolution of urban system present one brand-new landscape, but also put forward a new subject for planning of urban system. This article analyzes the properties of the traditional economic process and its essential effect on urban system; it makes a complete survey on the properties of new economic circumstances and its effect on re-forming of urban system; the complicated influential process and result are concluded into the aspects, such as new growth motive force, new economic organization, new location factor and new spatial phenomenon, and its inner effect mechanism in shown as well. In this article, the change process of urban system space is explained in four aspects: (1) dissimulation in the process of spatial agglomeration and diffusion; (2) change of “center-periphery” effect; (3) acceleration growth of axial regions; (4) re-forming of the world and regional urban system. Based on the above theoretical analysis and the properties & requests of new economic circumstances, this article finally puts forward four philosophies emphasized by urban system planning, and forms the new frame for drawing-up of urban system planning.展开更多
Urbanization level of Tianjian City was comprehensively assessed by mathematical methods such as geometrical center,center deviation,divergence measurement and uniformity measurement of the city in this study.The resu...Urbanization level of Tianjian City was comprehensively assessed by mathematical methods such as geometrical center,center deviation,divergence measurement and uniformity measurement of the city in this study.The results showed that Tianjin City has high divergence,lowuniformity,relatively low level of urbanization,so that the process of urbanization should be further enhanced.展开更多
The present paper aims at showing how it is possible to requalify the structures of an urban system, in order to increase its resistance and its correlative resilience, against natural calamities (earthquakes, hurrica...The present paper aims at showing how it is possible to requalify the structures of an urban system, in order to increase its resistance and its correlative resilience, against natural calamities (earthquakes, hurricanes, etc.), by adopting as reference criterion the Maximum Ordinality Principle (MOP). In this sense, the paper opens a radically new perspective in this field. In fact, the village assumed as a case study was modelled as a Self-Organizing System. This is because, although the village is usually considered as being solely made of buildings, streets, places and so on, in reality it has been conceived, planned and realized by human beings during several centuries. In addition, the people who actually leave in such an urban center, systematically deal with its maintenance, in order to possibly increase its functionality. This justifies the assumption of the village as being a Self-Organizing System and, consequently, it has been analyzed in the light of the MOP, which represents a valid reference principle for analyzing both “non-living”, “living” and “conscious” self-organizing systems.展开更多
With the implementation of economic reform and open policy, China has expanded her foreign trade, utilized a lot of foreign investment, and thethere its economy has been increasingly integrated into world economy. Be...With the implementation of economic reform and open policy, China has expanded her foreign trade, utilized a lot of foreign investment, and thethere its economy has been increasingly integrated into world economy. Because the coastal region is different in the level of socio-economic development, location and accessibility from inland region, the former has got more opporturuties of development. In the coastal region, the ekisting urban clusters are spreading and new ones are appearing. However, a large floating population, traffic jam, sprawl spread in urban land use and environmental pollution have become serious problems in coastal cities.展开更多
This paper studies developing history and power of city and town in Xiantao district and prediction method of urbanization level. It planes that city and towns is all around district centerXianto city, first, second t...This paper studies developing history and power of city and town in Xiantao district and prediction method of urbanization level. It planes that city and towns is all around district centerXianto city, first, second third town axes; first center of Xiantao district is Xiantao city, second are Penchang, Tonghaikou, Mazui town.展开更多
Economy is a major force in determining the hierarchy of urban system. As regional economy globalizes, urban systems in many countries are making their transition from the scale-based hierarchy to the networked system...Economy is a major force in determining the hierarchy of urban system. As regional economy globalizes, urban systems in many countries are making their transition from the scale-based hierarchy to the networked system, while that in China still maintains an administrative stratification. The paper discussed the triumph of Baigou Town in the East Baoding Sub-center Campaign. It significantly shattered the administrative hierarchy of the urban system in China, which owes largely to the new type of economical development, i.e. government-led fixed assets investment and real estate development, as demonstrated in the urban expansion. Under the pattern of "territory" logic, spatial planning not only lost efficacy, but also stimulated bottom-up over development in local areas. The paper recommended foreign action- and collaboration-oriented urban planning theories, and that the absolute top-down spatial blueprint planning must be abandoned, and a harmonious synergy of planning roles, work content and methodology be facilitated.展开更多
Several factors may contribute to on-going challenges for spatial planning and policy in megacities such as Rome, including rapid population shifts, poorly organized areas, and lack of data through which monitoring ur...Several factors may contribute to on-going challenges for spatial planning and policy in megacities such as Rome, including rapid population shifts, poorly organized areas, and lack of data through which monitoring urban growth and land use change. This research was conducted to examine past and current effects of the urbanization process, occurred over the large Roman urban system, on the basis of multi-source and multi-temporal optical remote sensing (RS) data, collected between 1990 and 2013. These changes were then validated via Geographic Information System (GIS) techniques, in a particular procedure applied to urban land/agricultural transformations. The proposed approach, based on geo-statistical methods, was used to calculate the index of innovative space (AP Index), useful for the monitoring of the urban sprawl phenomenon. Strong evidence of urban expansion over the north-eastern quarter of the city, accompanied by environmental degradation and loss of biodiversity, is provided. Urban infill developments are expected to emerge in the south-eastern areas too, and these might increase urban pressure as well. In conclusion, RS and GIS technologies together with ancillary data can be used to assist decision makers in preparing future plans to find out appropriate solutions to urbanization encroachment.展开更多
The paper made a preliminary study on the spatial structure of urbansystems which take Shenyang, Changchun and Harbin as centers respectively innortheast China. A law is found that the spatial stracture becomes gradua...The paper made a preliminary study on the spatial structure of urbansystems which take Shenyang, Changchun and Harbin as centers respectively innortheast China. A law is found that the spatial stracture becomes gradually loosewhile the level of aggregation' tends to rise from the south to the north based on themeasurement and calculation of fractal dimension and fractal structure factor. Theauthor discussed how the spatial patterns formed and lastly put forward suggestionsto improve the supervision of the urban systems in northeast China.展开更多
Following a half century of popularity, central place theory experienced 20 years of neglect when the new urban system theory of network modeling gained attention at the beginning of the 1990s. However, central place ...Following a half century of popularity, central place theory experienced 20 years of neglect when the new urban system theory of network modeling gained attention at the beginning of the 1990s. However, central place theory remains valid, and it seems there has been a reemergence with it. Using the Greater Pearl River Delta (Greater PRD) as an experimental study region, this paper intends to present an empirical study that validates central place theory and shows that it can be integrated into an overall regional urban system. The study uses the compound Central Place Importance (CPI) to evaluate whether there is a hierarchy among the urban centers within the study area. The results indicate the existence of a hierarchy. Furthermore, empirical observation finds distinct complementarity relationships, rank-size distributions, and co-operative actions between the different cities, thus substantiating the claim that central place theory can be incorporated into an overall regional urban system. Besides, the presence of the densely distributed modern infrastructure system also appears to constitute a dimension of the overall urban system. There need further theoretical and empirical studies in order to support this proposition.展开更多
Traffic at urban intersections frequently encounters unexpected obstructions,resulting in congestion due to uncooperative and priority-based driving behavior.This paper presents an optimal right-turn coordination syst...Traffic at urban intersections frequently encounters unexpected obstructions,resulting in congestion due to uncooperative and priority-based driving behavior.This paper presents an optimal right-turn coordination system for Connected and Automated Vehicles(CAVs)at single-lane intersections,particularly in the context of left-hand side driving on roads.The goal is to facilitate smooth right turns for certain vehicles without creating bottlenecks.We consider that all approaching vehicles share relevant information through vehicular communications.The Intersection Coordination Unit(ICU)processes this information and communicates the optimal crossing or turning times to the vehicles.The primary objective of this coordination is to minimize overall traffic delays,which also helps improve the fuel consumption of vehicles.By considering information from upcoming vehicles at the intersection,the coordination system solves an optimization problem to determine the best timing for executing right turns,ultimately minimizing the total delay for all vehicles.The proposed coordination system is evaluated at a typical urban intersection,and its performance is compared to traditional traffic systems.Numerical simulation results indicate that the proposed coordination system significantly enhances the average traffic speed and fuel consumption compared to the traditional traffic system in various scenarios.展开更多
This paper addresses urban sustainability challenges amid global urbanization, emphasizing the need for innova tive approaches aligned with the Sustainable Development Goals. While traditional tools and linear models ...This paper addresses urban sustainability challenges amid global urbanization, emphasizing the need for innova tive approaches aligned with the Sustainable Development Goals. While traditional tools and linear models offer insights, they fall short in presenting a holistic view of complex urban challenges. System dynamics (SD) models that are often utilized to provide holistic, systematic understanding of a research subject, like the urban system, emerge as valuable tools, but data scarcity and theoretical inadequacy pose challenges. The research reviews relevant papers on recent SD model applications in urban sustainability since 2018, categorizing them based on nine key indicators. Among the reviewed papers, data limitations and model assumptions were identified as ma jor challenges in applying SD models to urban sustainability. This led to exploring the transformative potential of big data analytics, a rare approach in this field as identified by this study, to enhance SD models’ empirical foundation. Integrating big data could provide data-driven calibration, potentially improving predictive accuracy and reducing reliance on simplified assumptions. The paper concludes by advocating for new approaches that reduce assumptions and promote real-time applicable models, contributing to a comprehensive understanding of urban sustainability through the synergy of big data and SD models.展开更多
Rapid urbanization has significantly altered urban spatial system.However,the specific spatio-temporal patterns of this transformation have not yet been fully revealed.Based on a review of the urbanization process in ...Rapid urbanization has significantly altered urban spatial system.However,the specific spatio-temporal patterns of this transformation have not yet been fully revealed.Based on a review of the urbanization process in the study area,the fractal dimensions of urban settlement size and spatial morphology amid rapid urbanization from 1999 to 2019 are calculated using the data from three nationally conducted land surveys,with the current urban built-up areas defined as the spatial units of the urban system study.The results demonstrate that,firstly,both the size and spatial morphology of the urban system exhibit fractal characteristics.The size distribution conforms to the rank-size distribution model and exhibits the characteristics of parallel advancement.Meanwhile,the fractal characteristics can be illustrated by using spatial differentiation of the growth multiples of built-up areas.Secondly,the urban system of Suzhou is well-founded,with a discernible tendency of transitioning from unorganized clusters to ordered systems and from a primate city-dominated structure to a hierarchical sequential pattern.Thirdly,in terms of spatial morphology,the capacity dimension D0 gradually develops into the ideal fractal dimension of urban morphology,while the information dimension D1 is chaotic,indicating that the change of fractal dimension is closely related to the stage of urbanization.The paper thus suggests that the urban system fractal characteristics should be incorporated into the city examination indicator system and be applied to optimize the urban system.展开更多
Considering the demographic polarization in China's urban system over the past three decades,this paper develops a comprehensive quantitative spatial equilibrium model to clarify the centripetal agglomeration effe...Considering the demographic polarization in China's urban system over the past three decades,this paper develops a comprehensive quantitative spatial equilibrium model to clarify the centripetal agglomeration effects,centrifugal commuting costs,locational fundamentals,and migration frictions on urban scale and the evolution of the urban system.The findings from theoretical model deduction,structural estimation,and counterfactual simulations indicate that improving commuting conditions or reducing migration frictions will lead to sustained population growth in mega and larger cities,resulting in a more concentrated urban system distribution.The equalization of agglomeration effects significantly drives population growth in small and medium cities,encouraging the urban system distribution to evolve toward a more uniform pattern.The amenity or productivity equalization of locational fundamentals will support population growth in small and medium cities,and eliminating inter-city housing price disparities will enhance the population size of mega and larger cities.Counterfactual policy evaluations show that a uniform distribution of the urban system promotes social equity but reduces overall social output,whereas a concentrated urban system distribution increases total social output but may hinder social equity.Therefore,this paper aims to balance efficiency and equity by proposing that,in the future,China's urban system should adopt a structural optimization path of stabilizing both ends while promoting the middle.This approach emphasizes the social equity of peripheral small and medium cities and the economic efficiency of super cities,focusing on the development of small and medium cities within metropolitan areas and urban agglomerations.It seeks to transition the urban system from a dumbbell-shaped structure to an olive-shaped structure,fostering a coordinated development pattern among large,medium,and small cities.展开更多
The evolution of cities into digitally managed environments requires computational systems that can operate in real time while supporting predictive and adaptive infrastructure management.Earlier approaches have often...The evolution of cities into digitally managed environments requires computational systems that can operate in real time while supporting predictive and adaptive infrastructure management.Earlier approaches have often advanced one dimension—such as Internet of Things(IoT)-based data acquisition,Artificial Intelligence(AI)-driven analytics,or digital twin visualization—without fully integrating these strands into a single operational loop.As a result,many existing solutions encounter bottlenecks in responsiveness,interoperability,and scalability,while also leaving concerns about data privacy unresolved.This research introduces a hybrid AI–IoT–Digital Twin framework that combines continuous sensing,distributed intelligence,and simulation-based decision support.The design incorporates multi-source sensor data,lightweight edge inference through Convolutional Neural Networks(CNN)and Long ShortTerm Memory(LSTM)models,and federated learning enhanced with secure aggregation and differential privacy to maintain confidentiality.A digital twin layer extends these capabilities by simulating city assets such as traffic flows and water networks,generating what-if scenarios,and issuing actionable control signals.Complementary modules,including model compression and synchronization protocols,are embedded to ensure reliability in bandwidth-constrained and heterogeneous urban environments.The framework is validated in two urban domains:traffic management,where it adapts signal cycles based on real-time congestion patterns,and pipeline monitoring,where it anticipates leaks through pressure and vibration data.Experimental results show a 28%reduction in response time,a 35%decrease in maintenance costs,and a marked reduction in false positives relative to conventional baselines.The architecture also demonstrates stability across 50+edge devices under federated training and resilience to uneven node participation.The proposed system provides a scalable and privacy-aware foundation for predictive urban infrastructure management.By closing the loop between sensing,learning,and control,it reduces operator dependence,enhances resource efficiency,and supports transparent governance models for emerging smart cities.展开更多
The rapid population and land urbanization not only promoted economic development but also affected the ecosystem service value(ESV).In the context of new-type urbanization and green development,it’s essential to inv...The rapid population and land urbanization not only promoted economic development but also affected the ecosystem service value(ESV).In the context of new-type urbanization and green development,it’s essential to investigate the impacts of urbanization on ESV in China.However,a comprehensive and dynamic framework to reveal the relationship between ESV and urbanization processes is lacking.This study adopted multi-source datasets to portray China’s urbanization process by integrating population,land,and economic urbanization,eval-uated the ESV changes of 10 categories by gross ecosystem product(GEP)methods,and explored ESV changes within different urbanization scales and speeds.The results showed rapid urbanization in the population,land,and economic dimensions in China,with a faster process of economic urbanization.The ESV also exhibited an increasing trend,with higher levels in the southeastern coastal regions and lower levels in the northwestern regions.Urbanization had positive impacts on ESV across various research units,but the ESV exhibited heteroge-neous changes across different urbanization scales,speeds,and their interactive effects.The response of ESV to dynamic urbanization processes was influenced by socio-economic,ecological,and policy factors;it is essential to combine targeted measures with general ecological product value realization methods in each unit to maximize social-economic-ecological benefits.展开更多
The complexity of coupled risks,which refer to the compounded effects of interacting uncertainties across multiple interdependent objectives,is inherent to cities functioning as dynamic,interdependent systems.A disrup...The complexity of coupled risks,which refer to the compounded effects of interacting uncertainties across multiple interdependent objectives,is inherent to cities functioning as dynamic,interdependent systems.A disruption in one domain ripples across various urban systems,often with unforeseen consequences.Central to this complexity are people,whose behaviors,needs,and vulnerabilities shape risk evolution and response effectiveness.Realizing cities as complex systems centered on human needs and behaviors is essential to understanding the complexities of coupled urban risks.This paper adopts a complex systems perspective to examine the intricacies of coupled urban risks,emphasizing the critical role of human decisions and behavior in shaping these dynamics.We focus on two key dimensions:cascading hazards in urban environments and cascading failures across interdependent exposed systems in cities.Existing risk assessment models often fail to capture the complexity of these processes,particularly when factoring in human decision-making.To tackle these challenges,we advocate for a standardized taxonomy of cascading hazards,urban components,and their interactions.At its core is a people-centric perspective,emphasizing the bidirectional interactions between people and the systems that serve them.Building on this foundation,we argue the need for an integrated,people-centric risk assessment framework that evaluates event impacts in relation to the hierarchical needs of people and incorporates their preparedness and response capacities.By leveraging real-time data,advanced simulations,and innovative validation methods,this framework aims to enhance the accuracy of coupled urban risk modeling.To effectively manage coupled urban risks,cities can draw from proven strategies in real complex systems.However,given the escalating uncertainties and complexities associated with climate change,prioritizing people-centric strategies is crucial.This approach will empower cities to build resilience not only against known hazards but also against evolving and unforeseen challenges in an increasingly uncertain world.展开更多
基金National Natural Science Foundation of China,No.41230632,No.41671166,No.41571159,No.41430636,No.41701128
文摘As two rising great powers, China and India have undergone similar development processes, but they also exhibit significant differences in development paths and patterns. The significant differences in political systems, economic systems, and developmental environment between the two countries have attracted great attention from scholars. This research focuses on the regional differences and spatial evolution processes in urbanization and urban systems between the two countries from a geographical perspective. Based on the demographic censuses of both countries and the urban population data from the United Nations, this paper systematically compared and analyzed the spatial characteristics of urbanization and urban systems in China and India using various methods including spatial analysis, parameter estimation, and nonparametric estimation. The results indicate that:(1) Since the 1990 s, the regional differences in urbanization in China have transformed from south-north differences to coastal-inland differences, whereas the north-south differences in India have been stable.(2) In recent years, the correlation between population density and urbanization rate kept increasing in China, while such correlation has been decreasing in India.(3) The economic reform posed significantly different effects on the spatial evolution of the urban systems in the two countries. The economic reform changed the major driving force for urban development in China from geographical and historical factors to the spatial structure of the economic system. However, in India, the driving forces for urban development have always been geographical and historical factors, and the economic reform even decreased the effect of the spatial structure of the economic system on urban development.
文摘The purpose of this research is to investigate the socio-economic development mechanism of China’s urban system in terms of spatial structure and its change. Totally 246 cities from 340 designated cities in 1985, and 488 from 640 designated cities in 1995 are selected as sample cities. And 22 attributes concerning urban features are analyzed to clarify the socio-economic characteristics and their changes in the urban system. Finally, the primary development factors are verified with the relationship of spatial structure and socio-economic characteristics. In conclusion, the socio-economic changes occurred more extremely than spatial structure changes. Furthermore, foreign investment be- came a major power for the development of China’s urban system in the period of 1985–1995.
基金Under the auspices of the National Natural Science Foundation of China(No.40001007).
文摘Urban system is the spatial reflection of the inner-deep social economic movement. New economic circumstances not only make the evolution of urban system present one brand-new landscape, but also put forward a new subject for planning of urban system. This article analyzes the properties of the traditional economic process and its essential effect on urban system; it makes a complete survey on the properties of new economic circumstances and its effect on re-forming of urban system; the complicated influential process and result are concluded into the aspects, such as new growth motive force, new economic organization, new location factor and new spatial phenomenon, and its inner effect mechanism in shown as well. In this article, the change process of urban system space is explained in four aspects: (1) dissimulation in the process of spatial agglomeration and diffusion; (2) change of “center-periphery” effect; (3) acceleration growth of axial regions; (4) re-forming of the world and regional urban system. Based on the above theoretical analysis and the properties & requests of new economic circumstances, this article finally puts forward four philosophies emphasized by urban system planning, and forms the new frame for drawing-up of urban system planning.
文摘Urbanization level of Tianjian City was comprehensively assessed by mathematical methods such as geometrical center,center deviation,divergence measurement and uniformity measurement of the city in this study.The results showed that Tianjin City has high divergence,lowuniformity,relatively low level of urbanization,so that the process of urbanization should be further enhanced.
文摘The present paper aims at showing how it is possible to requalify the structures of an urban system, in order to increase its resistance and its correlative resilience, against natural calamities (earthquakes, hurricanes, etc.), by adopting as reference criterion the Maximum Ordinality Principle (MOP). In this sense, the paper opens a radically new perspective in this field. In fact, the village assumed as a case study was modelled as a Self-Organizing System. This is because, although the village is usually considered as being solely made of buildings, streets, places and so on, in reality it has been conceived, planned and realized by human beings during several centuries. In addition, the people who actually leave in such an urban center, systematically deal with its maintenance, in order to possibly increase its functionality. This justifies the assumption of the village as being a Self-Organizing System and, consequently, it has been analyzed in the light of the MOP, which represents a valid reference principle for analyzing both “non-living”, “living” and “conscious” self-organizing systems.
文摘With the implementation of economic reform and open policy, China has expanded her foreign trade, utilized a lot of foreign investment, and thethere its economy has been increasingly integrated into world economy. Because the coastal region is different in the level of socio-economic development, location and accessibility from inland region, the former has got more opporturuties of development. In the coastal region, the ekisting urban clusters are spreading and new ones are appearing. However, a large floating population, traffic jam, sprawl spread in urban land use and environmental pollution have become serious problems in coastal cities.
文摘This paper studies developing history and power of city and town in Xiantao district and prediction method of urbanization level. It planes that city and towns is all around district centerXianto city, first, second third town axes; first center of Xiantao district is Xiantao city, second are Penchang, Tonghaikou, Mazui town.
基金Sponsored by 2013 Youth Fund of Humanities and Social Science Research Program of the Ministry of Education(13YJC840018)
文摘Economy is a major force in determining the hierarchy of urban system. As regional economy globalizes, urban systems in many countries are making their transition from the scale-based hierarchy to the networked system, while that in China still maintains an administrative stratification. The paper discussed the triumph of Baigou Town in the East Baoding Sub-center Campaign. It significantly shattered the administrative hierarchy of the urban system in China, which owes largely to the new type of economical development, i.e. government-led fixed assets investment and real estate development, as demonstrated in the urban expansion. Under the pattern of "territory" logic, spatial planning not only lost efficacy, but also stimulated bottom-up over development in local areas. The paper recommended foreign action- and collaboration-oriented urban planning theories, and that the absolute top-down spatial blueprint planning must be abandoned, and a harmonious synergy of planning roles, work content and methodology be facilitated.
文摘Several factors may contribute to on-going challenges for spatial planning and policy in megacities such as Rome, including rapid population shifts, poorly organized areas, and lack of data through which monitoring urban growth and land use change. This research was conducted to examine past and current effects of the urbanization process, occurred over the large Roman urban system, on the basis of multi-source and multi-temporal optical remote sensing (RS) data, collected between 1990 and 2013. These changes were then validated via Geographic Information System (GIS) techniques, in a particular procedure applied to urban land/agricultural transformations. The proposed approach, based on geo-statistical methods, was used to calculate the index of innovative space (AP Index), useful for the monitoring of the urban sprawl phenomenon. Strong evidence of urban expansion over the north-eastern quarter of the city, accompanied by environmental degradation and loss of biodiversity, is provided. Urban infill developments are expected to emerge in the south-eastern areas too, and these might increase urban pressure as well. In conclusion, RS and GIS technologies together with ancillary data can be used to assist decision makers in preparing future plans to find out appropriate solutions to urbanization encroachment.
文摘The paper made a preliminary study on the spatial structure of urbansystems which take Shenyang, Changchun and Harbin as centers respectively innortheast China. A law is found that the spatial stracture becomes gradually loosewhile the level of aggregation' tends to rise from the south to the north based on themeasurement and calculation of fractal dimension and fractal structure factor. Theauthor discussed how the spatial patterns formed and lastly put forward suggestionsto improve the supervision of the urban systems in northeast China.
文摘Following a half century of popularity, central place theory experienced 20 years of neglect when the new urban system theory of network modeling gained attention at the beginning of the 1990s. However, central place theory remains valid, and it seems there has been a reemergence with it. Using the Greater Pearl River Delta (Greater PRD) as an experimental study region, this paper intends to present an empirical study that validates central place theory and shows that it can be integrated into an overall regional urban system. The study uses the compound Central Place Importance (CPI) to evaluate whether there is a hierarchy among the urban centers within the study area. The results indicate the existence of a hierarchy. Furthermore, empirical observation finds distinct complementarity relationships, rank-size distributions, and co-operative actions between the different cities, thus substantiating the claim that central place theory can be incorporated into an overall regional urban system. Besides, the presence of the densely distributed modern infrastructure system also appears to constitute a dimension of the overall urban system. There need further theoretical and empirical studies in order to support this proposition.
基金supported by the Japan Society for the Promotion of Science(JSPS)Grants-in-Aid for Scientific Research(C)23K03898.
文摘Traffic at urban intersections frequently encounters unexpected obstructions,resulting in congestion due to uncooperative and priority-based driving behavior.This paper presents an optimal right-turn coordination system for Connected and Automated Vehicles(CAVs)at single-lane intersections,particularly in the context of left-hand side driving on roads.The goal is to facilitate smooth right turns for certain vehicles without creating bottlenecks.We consider that all approaching vehicles share relevant information through vehicular communications.The Intersection Coordination Unit(ICU)processes this information and communicates the optimal crossing or turning times to the vehicles.The primary objective of this coordination is to minimize overall traffic delays,which also helps improve the fuel consumption of vehicles.By considering information from upcoming vehicles at the intersection,the coordination system solves an optimization problem to determine the best timing for executing right turns,ultimately minimizing the total delay for all vehicles.The proposed coordination system is evaluated at a typical urban intersection,and its performance is compared to traditional traffic systems.Numerical simulation results indicate that the proposed coordination system significantly enhances the average traffic speed and fuel consumption compared to the traditional traffic system in various scenarios.
基金sponsored by the U.S.Department of Housing and Urban Development(Grant No.NJLTS0027-22)The opinions expressed in this study are the authors alone,and do not represent the U.S.Depart-ment of HUD’s opinions.
文摘This paper addresses urban sustainability challenges amid global urbanization, emphasizing the need for innova tive approaches aligned with the Sustainable Development Goals. While traditional tools and linear models offer insights, they fall short in presenting a holistic view of complex urban challenges. System dynamics (SD) models that are often utilized to provide holistic, systematic understanding of a research subject, like the urban system, emerge as valuable tools, but data scarcity and theoretical inadequacy pose challenges. The research reviews relevant papers on recent SD model applications in urban sustainability since 2018, categorizing them based on nine key indicators. Among the reviewed papers, data limitations and model assumptions were identified as ma jor challenges in applying SD models to urban sustainability. This led to exploring the transformative potential of big data analytics, a rare approach in this field as identified by this study, to enhance SD models’ empirical foundation. Integrating big data could provide data-driven calibration, potentially improving predictive accuracy and reducing reliance on simplified assumptions. The paper concludes by advocating for new approaches that reduce assumptions and promote real-time applicable models, contributing to a comprehensive understanding of urban sustainability through the synergy of big data and SD models.
基金supported by the National Natural Science Foundation of China Projects entitled“Study on the Process,Effect and Mechanism of Spatial Coupling of Urban Green Space and Residential Land Use:A Case Study of Nanjing”(No.51878429)the Postgraduate Research&Practice Innovation Program of Jiangsu Province entitled“Spatio-Temporal Coupling Characteristics of Park Green Space and Living Space and Its Configuration Pattern”(No.SJCX22_1597)。
文摘Rapid urbanization has significantly altered urban spatial system.However,the specific spatio-temporal patterns of this transformation have not yet been fully revealed.Based on a review of the urbanization process in the study area,the fractal dimensions of urban settlement size and spatial morphology amid rapid urbanization from 1999 to 2019 are calculated using the data from three nationally conducted land surveys,with the current urban built-up areas defined as the spatial units of the urban system study.The results demonstrate that,firstly,both the size and spatial morphology of the urban system exhibit fractal characteristics.The size distribution conforms to the rank-size distribution model and exhibits the characteristics of parallel advancement.Meanwhile,the fractal characteristics can be illustrated by using spatial differentiation of the growth multiples of built-up areas.Secondly,the urban system of Suzhou is well-founded,with a discernible tendency of transitioning from unorganized clusters to ordered systems and from a primate city-dominated structure to a hierarchical sequential pattern.Thirdly,in terms of spatial morphology,the capacity dimension D0 gradually develops into the ideal fractal dimension of urban morphology,while the information dimension D1 is chaotic,indicating that the change of fractal dimension is closely related to the stage of urbanization.The paper thus suggests that the urban system fractal characteristics should be incorporated into the city examination indicator system and be applied to optimize the urban system.
基金supported by the major program"Study on Constructing Coordinated Development Pattern of Large,Small and Medium Cities"(No.23ZDA048),approved by the National Social Science Fund of China.
文摘Considering the demographic polarization in China's urban system over the past three decades,this paper develops a comprehensive quantitative spatial equilibrium model to clarify the centripetal agglomeration effects,centrifugal commuting costs,locational fundamentals,and migration frictions on urban scale and the evolution of the urban system.The findings from theoretical model deduction,structural estimation,and counterfactual simulations indicate that improving commuting conditions or reducing migration frictions will lead to sustained population growth in mega and larger cities,resulting in a more concentrated urban system distribution.The equalization of agglomeration effects significantly drives population growth in small and medium cities,encouraging the urban system distribution to evolve toward a more uniform pattern.The amenity or productivity equalization of locational fundamentals will support population growth in small and medium cities,and eliminating inter-city housing price disparities will enhance the population size of mega and larger cities.Counterfactual policy evaluations show that a uniform distribution of the urban system promotes social equity but reduces overall social output,whereas a concentrated urban system distribution increases total social output but may hinder social equity.Therefore,this paper aims to balance efficiency and equity by proposing that,in the future,China's urban system should adopt a structural optimization path of stabilizing both ends while promoting the middle.This approach emphasizes the social equity of peripheral small and medium cities and the economic efficiency of super cities,focusing on the development of small and medium cities within metropolitan areas and urban agglomerations.It seeks to transition the urban system from a dumbbell-shaped structure to an olive-shaped structure,fostering a coordinated development pattern among large,medium,and small cities.
基金The researchers would like to thank the Deanship of Graduate Studies and Scientific Research at Qassim University for financial support(QU-APC-2025)。
文摘The evolution of cities into digitally managed environments requires computational systems that can operate in real time while supporting predictive and adaptive infrastructure management.Earlier approaches have often advanced one dimension—such as Internet of Things(IoT)-based data acquisition,Artificial Intelligence(AI)-driven analytics,or digital twin visualization—without fully integrating these strands into a single operational loop.As a result,many existing solutions encounter bottlenecks in responsiveness,interoperability,and scalability,while also leaving concerns about data privacy unresolved.This research introduces a hybrid AI–IoT–Digital Twin framework that combines continuous sensing,distributed intelligence,and simulation-based decision support.The design incorporates multi-source sensor data,lightweight edge inference through Convolutional Neural Networks(CNN)and Long ShortTerm Memory(LSTM)models,and federated learning enhanced with secure aggregation and differential privacy to maintain confidentiality.A digital twin layer extends these capabilities by simulating city assets such as traffic flows and water networks,generating what-if scenarios,and issuing actionable control signals.Complementary modules,including model compression and synchronization protocols,are embedded to ensure reliability in bandwidth-constrained and heterogeneous urban environments.The framework is validated in two urban domains:traffic management,where it adapts signal cycles based on real-time congestion patterns,and pipeline monitoring,where it anticipates leaks through pressure and vibration data.Experimental results show a 28%reduction in response time,a 35%decrease in maintenance costs,and a marked reduction in false positives relative to conventional baselines.The architecture also demonstrates stability across 50+edge devices under federated training and resilience to uneven node participation.The proposed system provides a scalable and privacy-aware foundation for predictive urban infrastructure management.By closing the loop between sensing,learning,and control,it reduces operator dependence,enhances resource efficiency,and supports transparent governance models for emerging smart cities.
基金supported by the Key Program of the National Natural Science Foundation of China(Grant No.41931293)the National Natural Science Foundation of China(Grant No.42271275).
文摘The rapid population and land urbanization not only promoted economic development but also affected the ecosystem service value(ESV).In the context of new-type urbanization and green development,it’s essential to investigate the impacts of urbanization on ESV in China.However,a comprehensive and dynamic framework to reveal the relationship between ESV and urbanization processes is lacking.This study adopted multi-source datasets to portray China’s urbanization process by integrating population,land,and economic urbanization,eval-uated the ESV changes of 10 categories by gross ecosystem product(GEP)methods,and explored ESV changes within different urbanization scales and speeds.The results showed rapid urbanization in the population,land,and economic dimensions in China,with a faster process of economic urbanization.The ESV also exhibited an increasing trend,with higher levels in the southeastern coastal regions and lower levels in the northwestern regions.Urbanization had positive impacts on ESV across various research units,but the ESV exhibited heteroge-neous changes across different urbanization scales,speeds,and their interactive effects.The response of ESV to dynamic urbanization processes was influenced by socio-economic,ecological,and policy factors;it is essential to combine targeted measures with general ecological product value realization methods in each unit to maximize social-economic-ecological benefits.
基金jointly supported by the National Natural Science Foundation of China(71821001,72371109,72071088,72074089,and 51938004)Strategic Study Project of Chinese Academy of Engineering(2022-JB-02)Project of Interdisciplinary Research Support Program in Huazhong University of Science and Technology(2023-32)。
文摘The complexity of coupled risks,which refer to the compounded effects of interacting uncertainties across multiple interdependent objectives,is inherent to cities functioning as dynamic,interdependent systems.A disruption in one domain ripples across various urban systems,often with unforeseen consequences.Central to this complexity are people,whose behaviors,needs,and vulnerabilities shape risk evolution and response effectiveness.Realizing cities as complex systems centered on human needs and behaviors is essential to understanding the complexities of coupled urban risks.This paper adopts a complex systems perspective to examine the intricacies of coupled urban risks,emphasizing the critical role of human decisions and behavior in shaping these dynamics.We focus on two key dimensions:cascading hazards in urban environments and cascading failures across interdependent exposed systems in cities.Existing risk assessment models often fail to capture the complexity of these processes,particularly when factoring in human decision-making.To tackle these challenges,we advocate for a standardized taxonomy of cascading hazards,urban components,and their interactions.At its core is a people-centric perspective,emphasizing the bidirectional interactions between people and the systems that serve them.Building on this foundation,we argue the need for an integrated,people-centric risk assessment framework that evaluates event impacts in relation to the hierarchical needs of people and incorporates their preparedness and response capacities.By leveraging real-time data,advanced simulations,and innovative validation methods,this framework aims to enhance the accuracy of coupled urban risk modeling.To effectively manage coupled urban risks,cities can draw from proven strategies in real complex systems.However,given the escalating uncertainties and complexities associated with climate change,prioritizing people-centric strategies is crucial.This approach will empower cities to build resilience not only against known hazards but also against evolving and unforeseen challenges in an increasingly uncertain world.
