Urban tourism is considered a complex system,and multiscale exploration of the organizational patterns of attraction networks has become a topical issue in urban tourism,so exploring the multiscale characteristics and...Urban tourism is considered a complex system,and multiscale exploration of the organizational patterns of attraction networks has become a topical issue in urban tourism,so exploring the multiscale characteristics and connection mechanisms of attraction networks is important for understanding the linkages between attractions and even the future destination planning.This paper uses geotagging data to compare the links between attractions in Beijing,China during four different periods:the pre-Olympic period(2004–2007),the Olympic Games and subsequent‘heat period’(2008–2013),the post-Olympic period(2014–2019),and the COVID-19(Corona Virus Disease 2019)pandemic period(2020–2021).The aim is to better understand the evolution and patterns of attraction networks at different scales in Beijing and to provide insights for tourism planning in the destination.The results show that the macro,meso-,and microscales network characteristics of attraction networks have inherent logical relationships that can explain the commonalities and differences in the development process of tourism networks.The macroscale attraction network degree Matthew effect is significant in the four different periods and exhibits a morphological monocentric structure,suggesting that new entrants are more likely to be associated with attractions that already have high value.The mesoscale links attractions according to the common purpose of tourists,and the results of the community segmentation of the attraction networks in the four different periods suggest that the functional polycentric structure describes their clustering effect,and the weak links between clusters result from attractions bound by incomplete information and distance,and the functional polycentric structure with a generally more efficient network of clusters.The pattern structure at the microscale reveals the topological transformation relationship of the regional collaboration pattern,and the attraction network structure in the four different periods has a very similar importance profile structure suggesting that the attraction network has the same construction rules and evolution mechanism,which aids in understanding the attraction network pattern at both macro and micro scales.Important approaches and practical implications for planners and managers are presented.展开更多
This paper presents some considerations about the definition and role of "medium-sized cities" in the processes of urban governance of the Italian regional systems, in line with the objectives of European programmin...This paper presents some considerations about the definition and role of "medium-sized cities" in the processes of urban governance of the Italian regional systems, in line with the objectives of European programming 2007-2013. Beginning from some theoretical considerations, the research objective is to delineate the features of the "new urban geography" of Campania region as it has been formed on the base of the social and economic processes that in the last 30 years have modified the regional urban system in the widest context of Mezzogiorno. To such aim, the paper is articulated in two parts: the first one in which the fundamental passages are re-called in the processes of development of Italian urban areas that have carried to new paradigms object of theoretical approaches still in course of definition, and the second one in which such processes are considered regarding the model of urban development of Campania, on which the research is concentrated. Specifically, the paper presents the case of two "middle cities" in the Campania region: Benevento and Salerno, which play a particularly important role in the design and development of a "regional network of medium-sized cities".展开更多
BACKGROUND:The present study aimed to explore the relationship between surgical methods,hemorrhage position,hemorrhage volume,surgical timing and treatment outcome of hypertensive intracerebral hemorrhage(HICH).METHOD...BACKGROUND:The present study aimed to explore the relationship between surgical methods,hemorrhage position,hemorrhage volume,surgical timing and treatment outcome of hypertensive intracerebral hemorrhage(HICH).METHODS:A total of 1 310 patients,who had been admitted to six hospitals from January 2004 to January 2008,were divided into six groups according to different surgical methods:craniotomy through bone fl ap(group A),craniotomy through a small bone window(group B),stereotactic drilling drainage(group C1 and group C2),neuron-endoscopy operation(group D) and external ventricular drainage(group E) in consideration of hemorrhage position,hemorrhage volume and clinical practice. A retrospective analysis was made of surgical timing and curative effect of the surgical methods.RESULTS:The effectiveness rate of the methods was 74.12% for 1 310 patients after onemonth follow-up. In this series,the disability rate was 44.82% 3–6 months after the operation. Among the 1 310 patients,241(18.40%) patients died after the operation. If hematoma volume was >80 mL and the operation was performed within 3 hours,the mortality rate of group A was signifi cantly lower than that of groups B,C,D,and E(P<0.05). If hematoma volume was 50–80 mL and the operation was performed within 6–12 hours,the mortality rate of groups B and D was lower than that of groups A,C and E(P<0.05). If hematoma volume was 20–50 mL and the operation was performed within 6–24 hours,the mortality rate of group C was lower than that of groups A,B and D(P<0.05).CONCLUSIONS:Craniotomy through a bone f lap is suitable for patients with a large hematoma and hernia of the brain. Stereotactic drilling drainage is suggested for patients with hematoma volume less than 80 mL. The curative effect of HICH individualized treatment would be improved via the suitable selection of operation time and surgical method according to the position and volume of hemorrhage.展开更多
This study focuses on the suburbanization and subcentering of population and examines the nature of spatial restructuring in terms of the population distribution in the Beijing metropolitan area.Instead of the classic...This study focuses on the suburbanization and subcentering of population and examines the nature of spatial restructuring in terms of the population distribution in the Beijing metropolitan area.Instead of the classic density function approach,we employ the nonparametric analysis to characterize the spatial pattern of population densities in the Beijing metropolitan area and identify the suburban subcenters.Our findings suggest that the population has spread with rapid urban growth in the Beijing metropolitan area,and the compact urban form has been replaced by a more dispersed polycentric spatial distribution.However,compared with the decentralization of western cities,the spatial extent of the decentralization of population in the Beijing metropolitan area is quite limited.The rapid growth of population in the near suburbs has expedited the sprawl of the central city,with a larger central agglomeration of population dominating the metropolitan area.In this sense,the spatial pattern of the Beijing metropolitan area is still characterized by the continuous compactness.However,our findings do provide the evidence that the city has been turning to a polycentric structure.We find significant population subcenters have emerged in the suburbs of Beijing since the 1980s.But the polycentricity emerged in the Beijing metropolitan area is very different by nature from that observed in Western cities.The subcenters emerged are adherent to the development scheme planned for the city,so it can be referred to as the so called 'planned polycentricity'.展开更多
This study models the impact of the shift from a monocentric private-car-oriented city to polycentric public-transport-oriented city. Metropolitan areas have suffered traffic problems in particular increase in travel ...This study models the impact of the shift from a monocentric private-car-oriented city to polycentric public-transport-oriented city. Metropolitan areas have suffered traffic problems in particular increase in travel time and travel distance. Urban expansion, population growth and road network development have led to urban sprawl in monocentric cities. In many monocentric cities, travel time and distance has steadily increased and is only expected to increase in the future. Excessive travel leads to several problems such as air pollution, noise, congestion, reduction in productive time, greenhouse emissions, and increased stress and accident rates. This study examines the interaction of land use and travel. A model was developed and calibrated to Melbourne and Riyadh conditions and used for scenario analysis. This model included two parts: a spatial model and a transport model. The scenario analysis included variations of residential and activity distribution, as well as conditions of public transport service.展开更多
The special economic zone(SEZ)is an important place-based policy adopted by the Chinese government to simulate regional and urban growth,and existing studies mainly focus on the impacts of SEZs on local economic outco...The special economic zone(SEZ)is an important place-based policy adopted by the Chinese government to simulate regional and urban growth,and existing studies mainly focus on the impacts of SEZs on local economic outcomes and productivity.This paper establishes the linkage between SEZ and urban spatial structure based on time-series nighttime light images spanning 2000 to 2020 in China.Through a set of time-varying difference-indifferences(DID)regressions at the county level,we find that the introduction of national SEZs has a significant negative impact on monocentricity,while provincial SEZs need to operate for 7 years before they have a substantial impact on spatial structure.However,the average effect masks great heterogeneity with respect to the characteristics and geographic location of zones.SEZs characterized by higher research and development(R&D)intensity,larger scale,and longer establishment duration have more pronounced effects on spatial structure.Geographically,the effects peak when SEZs are 5-15 km away from existing centers,and the effects of SEZs are mainly observed in urban areas and top-tier cities.展开更多
Our understanding of urban form depends on how we perceive the city.Much of the literature on urban form(1)has focused on the pre-industrial and industrial city,celebrating its compact form,contiguous functions and si...Our understanding of urban form depends on how we perceive the city.Much of the literature on urban form(1)has focused on the pre-industrial and industrial city,celebrating its compact form,contiguous functions and single dominant centre.More recently writings by Castels(2)and Soja(3)have described the dispersed,city of the post industrial era.This networked city triggered by the freedom afforded by the new technology(4)has exposed a new dimension to urban form.The model of the compact city advocated by those such as Lord Rogers Task Force for delivering the Urban Renaissance(5)is being questioned(6)and a new model of“high density nodes,in a high density landscape resulting in a low density city,”as in the Deltametropolis,described by Dirk Frieling(7).Compactness,cramming more development into the city and making public spaces of a higher density and quality,Rogers and Burdett argue(8)will make“urban living attractive,ecologically sustainable,economically strong and socially inclusive.”The alternative argument is that the economic success of cities is reliant on the networking of resources across a metropolitan region.Echenique argues(9)that cities disperse in their search for mobility and space.“Mobility increases the effi ciency of households and fi rms which in turn generates more income and profi ts.As income increases,so does the demand for space,residential and commercial alike.”Sustainability has become the current banner of political correctness.Sustainability however is a slippery word.It is easy to focus on one aspect and lose the value of its holistic meaning.For many architects“green buildings”equals a sustainable future.However,clever design solutions single-mindedly pursued with little regard to the wider exploration of the potential environmental savings that may be achieved through organisational innovation are only half the answer.A holistic approach concerned with both building and organisational design and focused on“lean thinking”(10)could make considerable inroads into reducing the ecological footprint.The paper draws on DEGW’s experience of advising major corporations and cities on strategies for managing the process of intensifi cation and change(11).It explores how major improvements might be gained in meeting our goals for the sustainable city through reconsidering the way we work and allocate space.The underlying proposition is that technology has offered us new opportunities which have changed our paradigm of living and working.This in turn has provided us with a new perception of the city,as a distributed series of high density centres connected by good public and private transport,within a low density landscape.The paper argues that considerable improvements in workplace sustainability can be achieved by applying a holistic approach.These may include a combination of strategies,from rethinking the organisation of work processes and the locations and time work is undertaken,to reducing the need for resources by a more intensive use of land and fl oor space.Disjointed,dispersed“urban sprawl”can be wasteful.The alternative emerging urban form is a planned,dispersed,“networked”city with well integrated public and private transport that yields greater choice of location and lifestyles so supporting social,economic and environmental sustainability.展开更多
Understanding the relationship between urban development and environmental sustainability to achieve‘double carbon’goals in China can be strengthened by evaluating the environmental effect of urban spatial structure...Understanding the relationship between urban development and environmental sustainability to achieve‘double carbon’goals in China can be strengthened by evaluating the environmental effect of urban spatial structure(US).However,there have been few studies that consider the differentiated effects of polycentric US(PUS)on carbon emissions from both functional and morphological perspectives simultaneously.Thus,taking China’s 31 provinces as experimental subjects,our study developed a novel framework with remotely sensed nighttime light(NTL)data to quantify morphological PUS(MPUS)and functional PUS(FPUS)from 2000 to 2019.Then,from these two dimensions,differentiated effects of PUS on carbon emissions were further examined.Results indicated that NTL data presented high potential in quantifying MPUS and FPUS.The effect of FPUS on carbon emission-cutting outperformed that of MPUS.In addition,the spillover effect effectively enhanced the decreasing effect of the FPUS on carbon emissions.Our empiricalfindings can provide guidance for the government in developing strategies for reducing carbon emissions and optimizing USs.展开更多
Polycentric urban development has profound impacts on urban development worldwide.Most studies have identified its complex drivers of social economy and natural condition while ignoring the state-led policy factors.In...Polycentric urban development has profound impacts on urban development worldwide.Most studies have identified its complex drivers of social economy and natural condition while ignoring the state-led policy factors.In recent years,China has undergone dramatic administrative division adjustment(ADA)during the process of unique state-led urbanization.However,as a crucial government strategy,the impacts of ADA on urban polycentricity remain unclear.This research investigates the relationship between ADA and urban polycentricity through spatial difference-in-differences models.The results reveal that ADA has contributed to the polycentric urban development in China.Specifically,boundary restructuring has more substantial impacts than hierarchy reorganization.In addition,ADA has significantly promoted urban polycentricity in local cities in central China and neighbouring cities in eastern China,while it has no significant effects in western China.Furthermore,ADA reshapes urban polycentricity mainly by the influencing mechanism of construction land and industrial structure.Policymakers should consider the various ADA’s impacts on urban polycentricity with socio-economic conditions.This research provides a deeper insight into urban spatial transformation with state-led drivers.展开更多
From 2000 to 2010 China experienced rapid economic development and urbanization.Many cities in economically developed areas have developed from a single-center status to polycentricity.In this study,we used explorator...From 2000 to 2010 China experienced rapid economic development and urbanization.Many cities in economically developed areas have developed from a single-center status to polycentricity.In this study,we used exploratory spatial data analysis (ESDA) to identify the population centers,which identified 232 cities in China as having urban centers.COMP was used to represent urban agglomeration,and POLYD (representing how far is the city’s sub-centers to the main center),POLYC (representing the number of a city’s centers),and POLYP (representing the population distributed between the main center and the sub-centers) were used to indicate urban polycentricity.Night light data were used to determine the CO2 emissions from various cities in China.A mixed model was used to study the impact of urban aggregation and polycentric data on the CO2 emission efficiency in 2000 and 2010.The study found that cities with higher compactness were distributed in coastal areas,and the cities with higher multicentricity were distributed in the Yangtze River Delta and Shandong Province.The more compact the city was,the less conducive it was to improving CO2 emission efficiency.Polycentric development of the city was conducive to improving the CO2 emission efficiency,but the number of urban centers had no significant relationship with the CO2 emission efficiency.Our research showed that the compactness and multicentricity of the city had an impact on the CO2 emission efficiency and provided some planning suggestions for the low carbon development of the city.展开更多
The use of multi-perspective and multi-scalar city networks has gradually developed into a range of critical approaches to understand spatial interactions and linkages. In particular, road linkages represent key chara...The use of multi-perspective and multi-scalar city networks has gradually developed into a range of critical approaches to understand spatial interactions and linkages. In particular, road linkages represent key characteristics of spatial dependence and distance decay, and are of great significance in depicting spatial relationships at the regional scale. Therefore, based on highway passenger flow data between prefecture-level administrative units, this paper attempted to identify the functional structures and regional impacts of city networks in China, and to further explore the spatial organization patterns of the existing functional regions, aiming to deepen our understanding of city network structures and to provide new cognitive perspectives for ongoing research. The research results lead to four key conclusions. First, city networks that are based on highway flows exhibit strong spatial dependence and hierarchical characteristics, to a large extent spatially coupled with the distributions of major megaregions in China. These phenomena are a reflection of spatial relationships at regional scales as well as core-periphery structure. Second, 19 communities that belong to an important type of spatial configuration are identified through community detection algorithm, and we suggest they are correspondingly urban economic regions within urban China. Their spatial metaphors include the administrative region economy, spatial spillover effects of megaregions, and core-periphery structure. Third, each community possesses a specific city network system and exhibits strong spatial dependence and various spatial organization patterns. Regional patterns have emerged as the result of multi-level, dynamic, and networked characteristics. Fourth, adopting a morphology-based perspective, the regional city network systems can be basically divided into monocentric, dual-nuclei, polycentric, and low-level equilibration spatial structures, while most are developing monocentrically.展开更多
Carbon neutrality has increasingly become a crucial agenda within global climate governance.Meanwhile,recent observations show that the governance architecture for carbon neutrality is transforming to polycentricity.H...Carbon neutrality has increasingly become a crucial agenda within global climate governance.Meanwhile,recent observations show that the governance architecture for carbon neutrality is transforming to polycentricity.However,there is still a lack of systematic investigation on carbon neutrality governance under the polycentric approach.Against this background,this study attempts to investigate the emergence and structure of polycentric climate governance,and to figure out to what extent the evolving polycentric system can contribute to the climate change governance towards carbon neutrality.The results show that efforts made by actors at transnational and subnational levels within the polycentric system can greatly complement the deficits of carbon neutrality governance by international regime and state government in many different domains.Besides,the identified issues,that are critical to carbon neutrality including climate legislation,adaptation,technology deployment and data authenticity and transparency,can be addressed in a more effective way through the coordination among multiple actors at multiple levels.Finally,further research should be conducted to address the dynamic linkages between international regimes as well as the issues related to small and medium-sized cities,and develop a comprehensive evaluation and accounting system for the risks and benefits of polycentric climate governance.展开更多
In recent years,with the increasingly serious traffic problems in large cities of China,transformation to polycentric urban spatial structure has been considered as an important initiative to improve the urban traffic...In recent years,with the increasingly serious traffic problems in large cities of China,transformation to polycentric urban spatial structure has been considered as an important initiative to improve the urban traffic performance.This study examines the traffic performance of the polycentric spatial structure of Harbin,and analyzes the factors influencing the traffic performance of the structure using the location reselection hypothesis theory.The results show that the polycentric spatial structure does not significantly improve Harbin’s traffic performance,and only the centers in peripheral areas indicate advantages in commuting speed and distance,to which the main reason is that the social and spatial factors reduce the importance of commuting costs,making long-distance commuting economically rational and hindering possible location reselection.It is an effective direction for the improvement of the traffic performance of polycentric spatial structure by facing up to the rationality of long-distance commuting and transportation demand,improving the location equilibrium of residential and employment resources,and constructing high-grade centers in peripheral areas in appropriate locations and with comprehensive functions.展开更多
基金Under the auspices of the National Natural Science Foundation of China(No.41971202)the National Natural Science Foundation of China(No.42201181)the Fundamental research funding targets for central universities(No.2412022QD002)。
文摘Urban tourism is considered a complex system,and multiscale exploration of the organizational patterns of attraction networks has become a topical issue in urban tourism,so exploring the multiscale characteristics and connection mechanisms of attraction networks is important for understanding the linkages between attractions and even the future destination planning.This paper uses geotagging data to compare the links between attractions in Beijing,China during four different periods:the pre-Olympic period(2004–2007),the Olympic Games and subsequent‘heat period’(2008–2013),the post-Olympic period(2014–2019),and the COVID-19(Corona Virus Disease 2019)pandemic period(2020–2021).The aim is to better understand the evolution and patterns of attraction networks at different scales in Beijing and to provide insights for tourism planning in the destination.The results show that the macro,meso-,and microscales network characteristics of attraction networks have inherent logical relationships that can explain the commonalities and differences in the development process of tourism networks.The macroscale attraction network degree Matthew effect is significant in the four different periods and exhibits a morphological monocentric structure,suggesting that new entrants are more likely to be associated with attractions that already have high value.The mesoscale links attractions according to the common purpose of tourists,and the results of the community segmentation of the attraction networks in the four different periods suggest that the functional polycentric structure describes their clustering effect,and the weak links between clusters result from attractions bound by incomplete information and distance,and the functional polycentric structure with a generally more efficient network of clusters.The pattern structure at the microscale reveals the topological transformation relationship of the regional collaboration pattern,and the attraction network structure in the four different periods has a very similar importance profile structure suggesting that the attraction network has the same construction rules and evolution mechanism,which aids in understanding the attraction network pattern at both macro and micro scales.Important approaches and practical implications for planners and managers are presented.
文摘This paper presents some considerations about the definition and role of "medium-sized cities" in the processes of urban governance of the Italian regional systems, in line with the objectives of European programming 2007-2013. Beginning from some theoretical considerations, the research objective is to delineate the features of the "new urban geography" of Campania region as it has been formed on the base of the social and economic processes that in the last 30 years have modified the regional urban system in the widest context of Mezzogiorno. To such aim, the paper is articulated in two parts: the first one in which the fundamental passages are re-called in the processes of development of Italian urban areas that have carried to new paradigms object of theoretical approaches still in course of definition, and the second one in which such processes are considered regarding the model of urban development of Campania, on which the research is concentrated. Specifically, the paper presents the case of two "middle cities" in the Campania region: Benevento and Salerno, which play a particularly important role in the design and development of a "regional network of medium-sized cities".
基金supported by a grant from Shanghai Pudong New Area(PWZxkq2011-01)
文摘BACKGROUND:The present study aimed to explore the relationship between surgical methods,hemorrhage position,hemorrhage volume,surgical timing and treatment outcome of hypertensive intracerebral hemorrhage(HICH).METHODS:A total of 1 310 patients,who had been admitted to six hospitals from January 2004 to January 2008,were divided into six groups according to different surgical methods:craniotomy through bone fl ap(group A),craniotomy through a small bone window(group B),stereotactic drilling drainage(group C1 and group C2),neuron-endoscopy operation(group D) and external ventricular drainage(group E) in consideration of hemorrhage position,hemorrhage volume and clinical practice. A retrospective analysis was made of surgical timing and curative effect of the surgical methods.RESULTS:The effectiveness rate of the methods was 74.12% for 1 310 patients after onemonth follow-up. In this series,the disability rate was 44.82% 3–6 months after the operation. Among the 1 310 patients,241(18.40%) patients died after the operation. If hematoma volume was >80 mL and the operation was performed within 3 hours,the mortality rate of group A was signifi cantly lower than that of groups B,C,D,and E(P<0.05). If hematoma volume was 50–80 mL and the operation was performed within 6–12 hours,the mortality rate of groups B and D was lower than that of groups A,C and E(P<0.05). If hematoma volume was 20–50 mL and the operation was performed within 6–24 hours,the mortality rate of group C was lower than that of groups A,B and D(P<0.05).CONCLUSIONS:Craniotomy through a bone f lap is suitable for patients with a large hematoma and hernia of the brain. Stereotactic drilling drainage is suggested for patients with hematoma volume less than 80 mL. The curative effect of HICH individualized treatment would be improved via the suitable selection of operation time and surgical method according to the position and volume of hemorrhage.
基金Under the auspices of National Key Basic Research Program of China (No. 2012CB955802)National Natural Science Foundation of China (No. 41001069)Grant Program of National Social Science Foundation of China (No.10zd&022)
文摘This study focuses on the suburbanization and subcentering of population and examines the nature of spatial restructuring in terms of the population distribution in the Beijing metropolitan area.Instead of the classic density function approach,we employ the nonparametric analysis to characterize the spatial pattern of population densities in the Beijing metropolitan area and identify the suburban subcenters.Our findings suggest that the population has spread with rapid urban growth in the Beijing metropolitan area,and the compact urban form has been replaced by a more dispersed polycentric spatial distribution.However,compared with the decentralization of western cities,the spatial extent of the decentralization of population in the Beijing metropolitan area is quite limited.The rapid growth of population in the near suburbs has expedited the sprawl of the central city,with a larger central agglomeration of population dominating the metropolitan area.In this sense,the spatial pattern of the Beijing metropolitan area is still characterized by the continuous compactness.However,our findings do provide the evidence that the city has been turning to a polycentric structure.We find significant population subcenters have emerged in the suburbs of Beijing since the 1980s.But the polycentricity emerged in the Beijing metropolitan area is very different by nature from that observed in Western cities.The subcenters emerged are adherent to the development scheme planned for the city,so it can be referred to as the so called 'planned polycentricity'.
文摘This study models the impact of the shift from a monocentric private-car-oriented city to polycentric public-transport-oriented city. Metropolitan areas have suffered traffic problems in particular increase in travel time and travel distance. Urban expansion, population growth and road network development have led to urban sprawl in monocentric cities. In many monocentric cities, travel time and distance has steadily increased and is only expected to increase in the future. Excessive travel leads to several problems such as air pollution, noise, congestion, reduction in productive time, greenhouse emissions, and increased stress and accident rates. This study examines the interaction of land use and travel. A model was developed and calibrated to Melbourne and Riyadh conditions and used for scenario analysis. This model included two parts: a spatial model and a transport model. The scenario analysis included variations of residential and activity distribution, as well as conditions of public transport service.
基金National Natural Science Foundation of China,No.42271262,No.42301185China Postdoctoral Science Foundation,No.2023M730284Fundamental Research Funds for the Central Universities,No.2022NTST17。
文摘The special economic zone(SEZ)is an important place-based policy adopted by the Chinese government to simulate regional and urban growth,and existing studies mainly focus on the impacts of SEZs on local economic outcomes and productivity.This paper establishes the linkage between SEZ and urban spatial structure based on time-series nighttime light images spanning 2000 to 2020 in China.Through a set of time-varying difference-indifferences(DID)regressions at the county level,we find that the introduction of national SEZs has a significant negative impact on monocentricity,while provincial SEZs need to operate for 7 years before they have a substantial impact on spatial structure.However,the average effect masks great heterogeneity with respect to the characteristics and geographic location of zones.SEZs characterized by higher research and development(R&D)intensity,larger scale,and longer establishment duration have more pronounced effects on spatial structure.Geographically,the effects peak when SEZs are 5-15 km away from existing centers,and the effects of SEZs are mainly observed in urban areas and top-tier cities.
文摘Our understanding of urban form depends on how we perceive the city.Much of the literature on urban form(1)has focused on the pre-industrial and industrial city,celebrating its compact form,contiguous functions and single dominant centre.More recently writings by Castels(2)and Soja(3)have described the dispersed,city of the post industrial era.This networked city triggered by the freedom afforded by the new technology(4)has exposed a new dimension to urban form.The model of the compact city advocated by those such as Lord Rogers Task Force for delivering the Urban Renaissance(5)is being questioned(6)and a new model of“high density nodes,in a high density landscape resulting in a low density city,”as in the Deltametropolis,described by Dirk Frieling(7).Compactness,cramming more development into the city and making public spaces of a higher density and quality,Rogers and Burdett argue(8)will make“urban living attractive,ecologically sustainable,economically strong and socially inclusive.”The alternative argument is that the economic success of cities is reliant on the networking of resources across a metropolitan region.Echenique argues(9)that cities disperse in their search for mobility and space.“Mobility increases the effi ciency of households and fi rms which in turn generates more income and profi ts.As income increases,so does the demand for space,residential and commercial alike.”Sustainability has become the current banner of political correctness.Sustainability however is a slippery word.It is easy to focus on one aspect and lose the value of its holistic meaning.For many architects“green buildings”equals a sustainable future.However,clever design solutions single-mindedly pursued with little regard to the wider exploration of the potential environmental savings that may be achieved through organisational innovation are only half the answer.A holistic approach concerned with both building and organisational design and focused on“lean thinking”(10)could make considerable inroads into reducing the ecological footprint.The paper draws on DEGW’s experience of advising major corporations and cities on strategies for managing the process of intensifi cation and change(11).It explores how major improvements might be gained in meeting our goals for the sustainable city through reconsidering the way we work and allocate space.The underlying proposition is that technology has offered us new opportunities which have changed our paradigm of living and working.This in turn has provided us with a new perception of the city,as a distributed series of high density centres connected by good public and private transport,within a low density landscape.The paper argues that considerable improvements in workplace sustainability can be achieved by applying a holistic approach.These may include a combination of strategies,from rethinking the organisation of work processes and the locations and time work is undertaken,to reducing the need for resources by a more intensive use of land and fl oor space.Disjointed,dispersed“urban sprawl”can be wasteful.The alternative emerging urban form is a planned,dispersed,“networked”city with well integrated public and private transport that yields greater choice of location and lifestyles so supporting social,economic and environmental sustainability.
基金supported by the National Natural Science Foundation of China(42101345).
文摘Understanding the relationship between urban development and environmental sustainability to achieve‘double carbon’goals in China can be strengthened by evaluating the environmental effect of urban spatial structure(US).However,there have been few studies that consider the differentiated effects of polycentric US(PUS)on carbon emissions from both functional and morphological perspectives simultaneously.Thus,taking China’s 31 provinces as experimental subjects,our study developed a novel framework with remotely sensed nighttime light(NTL)data to quantify morphological PUS(MPUS)and functional PUS(FPUS)from 2000 to 2019.Then,from these two dimensions,differentiated effects of PUS on carbon emissions were further examined.Results indicated that NTL data presented high potential in quantifying MPUS and FPUS.The effect of FPUS on carbon emission-cutting outperformed that of MPUS.In addition,the spillover effect effectively enhanced the decreasing effect of the FPUS on carbon emissions.Our empiricalfindings can provide guidance for the government in developing strategies for reducing carbon emissions and optimizing USs.
基金National Social Science Foundation of China,No.18ZDA040Humanities and Social Sciences Planning Project of the Ministry of Education in China,No.19YJA630079。
文摘Polycentric urban development has profound impacts on urban development worldwide.Most studies have identified its complex drivers of social economy and natural condition while ignoring the state-led policy factors.In recent years,China has undergone dramatic administrative division adjustment(ADA)during the process of unique state-led urbanization.However,as a crucial government strategy,the impacts of ADA on urban polycentricity remain unclear.This research investigates the relationship between ADA and urban polycentricity through spatial difference-in-differences models.The results reveal that ADA has contributed to the polycentric urban development in China.Specifically,boundary restructuring has more substantial impacts than hierarchy reorganization.In addition,ADA has significantly promoted urban polycentricity in local cities in central China and neighbouring cities in eastern China,while it has no significant effects in western China.Furthermore,ADA reshapes urban polycentricity mainly by the influencing mechanism of construction land and industrial structure.Policymakers should consider the various ADA’s impacts on urban polycentricity with socio-economic conditions.This research provides a deeper insight into urban spatial transformation with state-led drivers.
基金supported by the National Natural Science Foundation of China (No.41671180)the Shenzhen Technology Plan (No.JCYJ20170412150910443)。
文摘From 2000 to 2010 China experienced rapid economic development and urbanization.Many cities in economically developed areas have developed from a single-center status to polycentricity.In this study,we used exploratory spatial data analysis (ESDA) to identify the population centers,which identified 232 cities in China as having urban centers.COMP was used to represent urban agglomeration,and POLYD (representing how far is the city’s sub-centers to the main center),POLYC (representing the number of a city’s centers),and POLYP (representing the population distributed between the main center and the sub-centers) were used to indicate urban polycentricity.Night light data were used to determine the CO2 emissions from various cities in China.A mixed model was used to study the impact of urban aggregation and polycentric data on the CO2 emission efficiency in 2000 and 2010.The study found that cities with higher compactness were distributed in coastal areas,and the cities with higher multicentricity were distributed in the Yangtze River Delta and Shandong Province.The more compact the city was,the less conducive it was to improving CO2 emission efficiency.Polycentric development of the city was conducive to improving the CO2 emission efficiency,but the number of urban centers had no significant relationship with the CO2 emission efficiency.Our research showed that the compactness and multicentricity of the city had an impact on the CO2 emission efficiency and provided some planning suggestions for the low carbon development of the city.
基金National Natural Science Foundation of China,No.41530751,No.41471113,No.41601165
文摘The use of multi-perspective and multi-scalar city networks has gradually developed into a range of critical approaches to understand spatial interactions and linkages. In particular, road linkages represent key characteristics of spatial dependence and distance decay, and are of great significance in depicting spatial relationships at the regional scale. Therefore, based on highway passenger flow data between prefecture-level administrative units, this paper attempted to identify the functional structures and regional impacts of city networks in China, and to further explore the spatial organization patterns of the existing functional regions, aiming to deepen our understanding of city network structures and to provide new cognitive perspectives for ongoing research. The research results lead to four key conclusions. First, city networks that are based on highway flows exhibit strong spatial dependence and hierarchical characteristics, to a large extent spatially coupled with the distributions of major megaregions in China. These phenomena are a reflection of spatial relationships at regional scales as well as core-periphery structure. Second, 19 communities that belong to an important type of spatial configuration are identified through community detection algorithm, and we suggest they are correspondingly urban economic regions within urban China. Their spatial metaphors include the administrative region economy, spatial spillover effects of megaregions, and core-periphery structure. Third, each community possesses a specific city network system and exhibits strong spatial dependence and various spatial organization patterns. Regional patterns have emerged as the result of multi-level, dynamic, and networked characteristics. Fourth, adopting a morphology-based perspective, the regional city network systems can be basically divided into monocentric, dual-nuclei, polycentric, and low-level equilibration spatial structures, while most are developing monocentrically.
基金Financial support was obtained from the National Key Research and Development Program of China(2018YFA0606504,2018YFC1509008)National Natural Science Foundation of China(72140007,71804178,71573249).
文摘Carbon neutrality has increasingly become a crucial agenda within global climate governance.Meanwhile,recent observations show that the governance architecture for carbon neutrality is transforming to polycentricity.However,there is still a lack of systematic investigation on carbon neutrality governance under the polycentric approach.Against this background,this study attempts to investigate the emergence and structure of polycentric climate governance,and to figure out to what extent the evolving polycentric system can contribute to the climate change governance towards carbon neutrality.The results show that efforts made by actors at transnational and subnational levels within the polycentric system can greatly complement the deficits of carbon neutrality governance by international regime and state government in many different domains.Besides,the identified issues,that are critical to carbon neutrality including climate legislation,adaptation,technology deployment and data authenticity and transparency,can be addressed in a more effective way through the coordination among multiple actors at multiple levels.Finally,further research should be conducted to address the dynamic linkages between international regimes as well as the issues related to small and medium-sized cities,and develop a comprehensive evaluation and accounting system for the risks and benefits of polycentric climate governance.
文摘In recent years,with the increasingly serious traffic problems in large cities of China,transformation to polycentric urban spatial structure has been considered as an important initiative to improve the urban traffic performance.This study examines the traffic performance of the polycentric spatial structure of Harbin,and analyzes the factors influencing the traffic performance of the structure using the location reselection hypothesis theory.The results show that the polycentric spatial structure does not significantly improve Harbin’s traffic performance,and only the centers in peripheral areas indicate advantages in commuting speed and distance,to which the main reason is that the social and spatial factors reduce the importance of commuting costs,making long-distance commuting economically rational and hindering possible location reselection.It is an effective direction for the improvement of the traffic performance of polycentric spatial structure by facing up to the rationality of long-distance commuting and transportation demand,improving the location equilibrium of residential and employment resources,and constructing high-grade centers in peripheral areas in appropriate locations and with comprehensive functions.