Character of population distribution is one of the focuses studied by urban geography. Using the fifth national census data as basic data and using areal interpolation method, this paper analyzes character of urban po...Character of population distribution is one of the focuses studied by urban geography. Using the fifth national census data as basic data and using areal interpolation method, this paper analyzes character of urban population dis- tribution of Shenyang City, Northeast China, in terms of three aspects of statistical character, spatial auto-correlation and spatial structure. Furthermore, this research analyzes the factors affecting the population distribution of the city. The main conclusions include: 1) There is an obvious structure character of population distribution in the grid with a grain of 300m, which is appropriate scale when researching population distribution in Shenyang City. 2) Urban population dis- tribution has the character of assembling while population density distribution takes on variability in Shenyang City. 3) Population density distribution shows spatial auto-correlation within 7.36km. Spatial heterogeneity of population density is low. 4) Urban center, population distribution barycenter and population density maximum points separate each other. Population density distribution has multi-cores character. 5) Layout of governments, primary schools, middle schools, colleges, hospitals and marketplaces affects population distribution directly. With the increase of distance to these factors, population density decreases as logarithm.展开更多
To shed light on the general patterns and trends in urban sprawl research,and to provide reference for future study,bibliometric analysis and refined analysis are conducted for publications in this area from 1991 to 2...To shed light on the general patterns and trends in urban sprawl research,and to provide reference for future study,bibliometric analysis and refined analysis are conducted for publications in this area from 1991 to 2011.The general publication output,the global geographical distribution of the authors,the funding and institutions involved,the research areas,and the source titles are analyzed and discussed.Scholars in the United States and China have produced most of the documents in urban sprawl and these two countries are also the largest contributors in terms of funding and institutions.′Environmental Sciences&Ecology′,′Urban Studies′,and′Geography′are the most common research areas,and the journal titled Urban Studies has contributed the most articles.Furthermore,the refined analyses on the 500 top-cited and most relevant publications have revealed that research on urban sprawl is closely associated with the categories of′Urban form and development′,′Land use/land development′and′environment/ecology/biology′.Conclusions are made with respect to the basic paradigm of research on urban sprawl.The multi-disciplinary research into urban sprawl are expected to be more diversified and integrated.展开更多
In this paper, the verticalseismic effects on tunnels are studied based on a classic mass–damper–spring model. An analyticaldiscrete modelof urban underground tunnels subjected to verticalearthquake excitations is p...In this paper, the verticalseismic effects on tunnels are studied based on a classic mass–damper–spring model. An analyticaldiscrete modelof urban underground tunnels subjected to verticalearthquake excitations is proposed by considering the first verticalvibration mode. Taking a light railproject in Tianjin as an example, this study uses the proposed discrete modelto analyze the displacements of tunneland soilunder verticalearthquake excitations. The soildisplacement responses at different tunnellocations are analyzed with linear random vibration theory.The computationalcost is greatly reduced using the proposed model. It can be seen that different from the case of horizontalearthquakes, the displacement responses under verticalearthquake excitations keep growing after seismic acceleration reaches its peak for a short duration, and then,they begin to decay. The soils at different positions around the tunnels have large relative displacement under verticalearthquake excitations. Moreover, a finite-element modelis also established for displacement responses using ABAQUS.The comparison with the results of the finite-element modelshows that the results of the proposed discrete modelare available.展开更多
From the angle of ecology,urban agg lomeration presents relevant types of landscape structure,which in-clude Patch,Corridor and Matrix.There are different landscape feature s and different problems in differen t devel...From the angle of ecology,urban agg lomeration presents relevant types of landscape structure,which in-clude Patch,Corridor and Matrix.There are different landscape feature s and different problems in differen t development phases.This paper has put forward fi ve basic conditions for security pattern of landscape ecology of urban agglomeration,described quantitatively the featu res for landscape ecology in Wuxi,an d analyzed ecological background of spatial expan-sion and spatial organization of urb an development in Wuxi.From the angle of ecological land use and non-ecological land use,the paper has analyzed the featu res of land use and ecological distribution of land in the urban area.The s patial mod-el of cities and towns in Wuxi is composed of one metropolis,two urban zones and three development axes.This th esis has planned preliminarily ecologic al protection network at four levels in the urban region according to four layers.At last,combining landscape ecology with ur ban space,a tentative security pattern of landscape ecology has been pla nned in Wux-i,namely Source-Buffer Zone and Metropolis,Radiating Routes and Expan sion Direction of City,Strategic Point and Interac-tion between Cities and Towns,Inter-Source Linkage-Corridor of a Stabl e Landscape Structure.展开更多
This paper raises the comparison method of operational stages of the real estate market. In order to select similar operational stages, we established an analysis model by applying fuzzy grade-of-membership clustering...This paper raises the comparison method of operational stages of the real estate market. In order to select similar operational stages, we established an analysis model by applying fuzzy grade-of-membership clustering in this paper. Firstly, we select the materials information of the real estate market in America, Germany and Japan. Secondly, the real estate markets of America, Germany and Japan are divided into several different stages. Lastly, we apply the method of fuzzy grade-of-membership clustering to select comparable stages. The result of analysis indicates that the real estate market of Japan and Germany (1960-1980) are similar to the market in China.展开更多
Based on the National Land Use/Cover Database of China(NLUD-C) in the end of the 1980s(the 1980s,hereafter), 1995, 2000, 2005, and 2010, 665 cities were selected to study the size distribution and its changes of urban...Based on the National Land Use/Cover Database of China(NLUD-C) in the end of the 1980s(the 1980s,hereafter), 1995, 2000, 2005, and 2010, 665 cities were selected to study the size distribution and its changes of urban lands in China. In this study, the spatiotemporal evolutions of urban land size distribution as well as the influence of administrative-level on these cities were explored by combining urban spatial positions and administrative-levels. Results indicate that: 1) City size distribution using urban lands was more practical and reasonable than using non-agricultural population. 2) In the 1980s, cities with ascending urban land rank were centralized in Eastern China, specially the Changjiang(Yangtze) River Delta, the Zhujiang(Pearl) River Delta, and Beijing-Tianjin-Hebei region. Cities in Central, Western, and Northeast China mainly indicated descending urban land rank. 3) The transfer of national development focus resulted in cities with ascending urban land rank becoming evenly distributed nationwide; however, this trend was slightly centralized around Chengdu, Chongqing, and Wuhan in different periods. 4) During the 1980s to 2010, the proportion of cities with ascending urban land rank in provincial capitals, municipalities, and special administrative regions(high-level cities, hereafter) was consistently higher than those in prefecture- and county-level cities except for 2005–2010. The ranks of the majority of the prefecture- and county-level cities were mainly descending, supported by ascending; the proportion of cities with unchanged rank is small. This study breaks through the bottleneck of traditional research in the area of city size distribution by examining urban land replacing the non-agricultural population. The current study also provides scientific explanation for the healthy and reasonable development of urban land as well as the coordinated development of population urbanization and land urbanization.展开更多
The institutional environment in China has quite evidently changed during modern socio-economic transitions.Driven both by local government and by marketing force,urban social space was redistributed after the reform ...The institutional environment in China has quite evidently changed during modern socio-economic transitions.Driven both by local government and by marketing force,urban social space was redistributed after the reform of urban land and real estate policies.Urban renewal makes for wide differential rent and therefore gentrification is occurring in China.This paper analyzes the background and institutional environment of gentrification in China,and further discusses the process,characteristics and evolutionary mechanisms in the case of Nanjing,through investigation of the attributes of 1075 residential communities built during the 1998-2008 at a macro level,and interviewing the residents and analyzing questionnaires in 6 different and typical communities at a micro level.As a socio-spatial course of two-way interaction,gentrification is divided into 3 stages of incubation,occurrence and fast development,according to the time of landmark events and policy reform on the leasehold of land in Nanjing during socio-economic transition.In terms of the socio-spatial characteristics of gentrification in Nanjing,the gentrification process under the trajectory of urban renewal makes urban social space present a new circle-layer structure;the rise of quite a number of gated communities results in the fragmentation of social space and privatization of public space;the management mode of modern communities and the change of life style have aggravated the indifference of neighborhood relationship of gentrified communities.Based on the empirical evidence of this study,this paper indicates that gentrification is quite different between China and western countries with respect to spatio-temporal order,dominant forces,paths of realization and spatial expression,and it further reveals the dynamic mechanism of gentrification developing in China at the present stage.展开更多
The aim of this paper is to present the urban history of Juiz de Fora, a city with some 500,000 inhabitants in southeastern Brazil, and discuss how strategic decisions about the planning and construction of roads and ...The aim of this paper is to present the urban history of Juiz de Fora, a city with some 500,000 inhabitants in southeastern Brazil, and discuss how strategic decisions about the planning and construction of roads and highways can determine ways of life in a city. While paths may integrate landholdings and territories, they may also segregate communities and environments, causing deep rifts in the fabric of urban and land areas. The growth of Juiz de Fora is particularly marked by the construction of paths. This article reviews the local urban history from the establishment of paths in the city, to an analysis of the major impact and benefits they have had, notably on the local economy and demographics, as well as on the conservation of the local environment: Issues that are frequently relegated to a secondary role in the cost-benefit analysis of the city's planning decisions. After analysis of the case study, the authors concluded that citizens should be included on the agenda of the city, from spectators to actors of daily urban life.展开更多
Demographic urbanization caused great changes in scale of residents' consumption and residents' lifestyle and then impacted changes of regional household energy consumption. This paper expanded Logarithmic Mea...Demographic urbanization caused great changes in scale of residents' consumption and residents' lifestyle and then impacted changes of regional household energy consumption. This paper expanded Logarithmic Mean Decomposition Index method through introducing variables of urbanization and residential consumption into the model. It also analyzed the influences of six factors as energy structure, energy intensity, population scale, urbanization, residential consumption, and consumption inhibit on regional household energy consumption. Results showed that in 2003-2012, impact of urbanization on regional household energy consumption of Chinese three areas was significantly higher than population size. The "population gathered in eastern region" phenomenon caused eastern region getting the largest population scale effect. Driving force of residential consumption on regional household energy consumption was much higher than the other five effects. Due to the comparative advantage of residential consumption compared with government consumption, investment, and net export, the decrease of consumption ratio promoted the growth of regional household energy consumption. Energy intensity in Chinese three regions kept reducing in 2003-2012. The progress of energy utilization technology slowed the growth of regional household energy consumption, and energy intensity effect was most significant in the central region.展开更多
Construction of tunnels in urban areas requires assessment of the impact of tunneling on the stability and integrity of existing pile foundations. We have focused our attention to the analysis of the carrying capacity...Construction of tunnels in urban areas requires assessment of the impact of tunneling on the stability and integrity of existing pile foundations. We have focused our attention to the analysis of the carrying capacity of pile foundations provided by the impact of construction of urban tunnels on adjacent pile foundations, under the engineering background of the construction of the # 2 Line of the Guangzhou subway. It is carried out using a fast Lagrangian analysis of a continuum in a 3D numerical code, which is an elastoplastic three-dimensional finite difference model, to simulate the response of piles under the entire process of metro tunneling (deactivation of soil element and activation of the lining). The adjacent stratum around the tunnel is classified into three regions: Zone Ⅰ (upper adjacent stratum of tunnel), Zone Ⅱ (45°-upper-lateral adjacent stratum of tunnel) and Zone Ⅲ (lateral adjacent stratum of tunnel). In each region one typical pile is chosen to be calculated and analyzed in detail. Numerical simulations are mainly conducted at three points of each pile shaft: the side-friction force of the pile, the tip resistance of the pile and the axial loading of the pile. A contrasting analysis has been conducted both in the response of typical piles in different regions and from computer calculated values with site monitoring values. The results of numerical simulations show that the impact on carrying capacity of the piles lies mainly in the impact of construction of urban tunnels on the side-friction forces and the tip resistance of piles. The impact differs considerably among the different strata zones where the pile tips are located. The complicated rules of side-friction force and tip resistance of piles has resulted in complicated rules of pile axial loading thus, in the end, it impacts the carrying capacity of pile-foundations. It is necessary to take positive measures, such as stratum grouting stabilization or foundation underpinning, etc, to deal with the carrying capacity and the settlement of pile-foundations. The results are of value to similar engineering projects.展开更多
Following the Great East Japan Earthquake in March 2011, the demand for bottled water increased sharply. In this paper, the authors analyze who purchased more bottled water after the earthquake using Quick Purchase Re...Following the Great East Japan Earthquake in March 2011, the demand for bottled water increased sharply. In this paper, the authors analyze who purchased more bottled water after the earthquake using Quick Purchase Report data. The results are as follows: first, consumers who before the earthquake tended to purchase less bottled water tended to increase the volume purchased after the earthquake; second, the motives for purchasing bottled water after the earthquake differed between consumers in the Tokyo and Osaka metropolitan districts.展开更多
Shadow is one of the major problems in remotely sensed imagery which hampers the accuracy of information extraction and change detection.In these images,shadow is generally produced by different objects,namely,cloud,m...Shadow is one of the major problems in remotely sensed imagery which hampers the accuracy of information extraction and change detection.In these images,shadow is generally produced by different objects,namely,cloud,mountain and urban materials.The shadow correction process consists of two steps:detection and de-shadowing.This paper reviews a range of techniques for both steps,focusing on urban regions(urban shadows),mountainous areas(topographic shadow),cloud shadows and composite shadows.Several issues including the problems and the advantages of those algorithms are discussed.In recent years,thresholding and recovery techniques have become important for shadow detection and de-shadowing,respectively.Research on shadow correction is still an important topic,particularly for urban regions(in high spatial resolution data) and mountainous forest(in high and medium spatial resolution data).Moreover,new algorithms are needed for shadow correction,especially given the advent of new satellite images.展开更多
The geochemical baseline is the fundamental reference for environmental change and assessment.In this article we describe cluster and regression analyses with a normalization procedure.The elements Sc and Ag were chos...The geochemical baseline is the fundamental reference for environmental change and assessment.In this article we describe cluster and regression analyses with a normalization procedure.The elements Sc and Ag were chosen to calculate the environmental geochemical baseline.The geoaccumulation index was calculated and mapped to indicate the environmental quality of the soil.The results show that the urban areas are barely polluted with Ni and Cr but the rural areas in the southern part of the city, and the western part of the lake,are polluted with Ni,Cr,and Cu at the second level.On the other hand,the rural areas in the southern part of the city,and the western part of the lake,are polluted with As at a moderate level.The other area is polluted at the second level.An increase in As pollution occurs in a direction from northeast to southwest.The Cd pollution follows a trend similar to As,with an additional smaller contaminated area polluted at levelⅢ.The Hg pollution typical of urban areas occurs in the main and northern parts of the city.The geochemical accumulation index decreases from the city center to the periphery.The highest pollution level reaches levelⅣ,which indicates that the soil is seriously polluted with Hg.The southern part of the city and the rural areas to the west of the lake are not contaminated with Hg.Geological factors and the disturbance from human activities are both possible major factors:further research is needed to identify them.展开更多
According to the Chinese GB50011-2001 code and the recommended provisions of FEMANEHRP and EUROCODE 8, by using shear wave velocity and borehole data, the site classification is evaluated for a typical soft soil site ...According to the Chinese GB50011-2001 code and the recommended provisions of FEMANEHRP and EUROCODE 8, by using shear wave velocity and borehole data, the site classification is evaluated for a typical soft soil site on the Yantai seacoast. The site seismic ground motion effect is analyzed and the influence of the coastal soil on design ground motion parameters is discussed. The results show that the brief site classification can not represent the real conditions of a soft soil site; the soft soil on the coast has a remarkable impact on the magnitude and spectrum of ground motion acceleration. The magnification on peak acceleration is bigger, however, due to the nonlinear deformation of the soil. The magnification is reduced noulinearly with the increase of input ground motion; the spectrum is broadened and the characteristic period elongated on the soft soil site.展开更多
Existing quantitative migration studies are mainly at the inter-region or inter-province level for lacking of detailed geo-referenced migration data.Meanwhile,few of them integrate explorative spatial data analysis an...Existing quantitative migration studies are mainly at the inter-region or inter-province level for lacking of detailed geo-referenced migration data.Meanwhile,few of them integrate explorative spatial data analysis and spatial regression model into migration analysis.Based on aggregated registered floating population data from 2005 to 2008,the phenomena that population floating to Yiwu City in Zhejiang Province is analyzed at the provincial and county levels.The spatial layout of Yiwu's pull forces is proved as a V-shaped pattern excluding Sichuan Province based on map visualization method.Using the migration ratio in 2007 as an explanatory variable,two models are compared using ordinary least square,spatial error model and spatial lag model methods for county-level data in Jiangxi and Anhui provinces.The model with migration stock provides an improved fitting over the model without migration stock according to the model fitting results.The floating population flocking into Yiwu City from Jiangxi is determined mostly by migration stock while the determinant factors are migration stock and distance to Yiwu City for Anhui.The distance-decay effect is true for migration flow from Anhui to Yiwu City while the distance rule is not confirmed in Jiangxi with the best fitting model.The correlation between per capita net income of rural labor forces and migration ratio is not significant in Jiangxi and significant but at the 0.1 level only in Anhui.Further analysis shows that the distance,income and man-land ratio are important factors to explain population floating at earlier stage.However,as the dynamic population floating process evolves,the determinant factor would be migration stock.展开更多
This paper principally focuses on land use dynamics,urban expansion and underlying driving forces in the Natural Wetland Distribution Area(NWDA)of Fuzhou City in the southeastern China.Based on time series Landsat TM/...This paper principally focuses on land use dynamics,urban expansion and underlying driving forces in the Natural Wetland Distribution Area(NWDA)of Fuzhou City in the southeastern China.Based on time series Landsat TM/ETM+imageries and historical data,relationships between urban land expansion and its influencing factors from 1989 to 2009 were analyzed by using an integrated approach of remote sensing(RS)and geographic information system(GIS)techniques.The results showed that built-up land increased from 151.16 km2in 1989 to 383.76 km 2in 2009. Approximately 64.25%of the newly emerging built-up land was converted from cropland(29.47%),forest and shrub (25.78%),water(3.73%),wetland(4.61%),and bare land(0.66%)during 1989 and 2009.With a remarkable decrease in cropland,the proportion of non-agricultural population increased by 23.6%.Moreover,rapid development of infrastructures,facilities,industrial parks,and urban and rural settlements along the Minjiang River resulted in the eastward and southward expansion of built-up land.Additionally,the growth pattern of built-up land in the NWDA is highly correlated with socio-economic factors,including the gross domestic product(GDP),GDP per capita,and structure of industry.As a result,the observed environmental degradation such as loss of cropland and wetland due to heavy pressure of rapid urbanization have greatly impaired the carrying capacity of city.Thus,in addition to scientific and rational policies towards minimizing the adverse effects of urbanization,coordination between the administrative agencies should be urgently strengthened to balance the conflicts between urban development and ecological conservation to make sure the sustainable land use.展开更多
Integrated transportation and land use studies are of major interest to planners because they consider the interaction between transportation development and land use change. Quantifying the impact of transport infras...Integrated transportation and land use studies are of major interest to planners because they consider the interaction between transportation development and land use change. Quantifying the impact of transport infrastructure on land use change is necessary for evaluating the role of transportation development in the process of land use and land cover change in the urban-rural fringe. Taking Qixia District of Nanjing City, Jiangsu Province, China as a typical urban-rural fringe area, this paper analyzes the patterns and charac- teristics of land use change along three major transportation arteries using land use data from 2000 and 2008. We examine the spatial differentiation and gradient of land use pattern around railway, expressway, and highway corridors to investigate whether land use change in the urban-rural fringe is related to distance from transportation arteries and to clarify the varying impacts of different forms of transport infrastructure on land use patterns. We find that construction land generally tends to be located close to major transportation arteries, and that railways have the most obvious influence on land use change in the urban-rural fringe, while the impact of expressways was not significant. We conclude that there exists a causal relationship between the presence of transportation arteries and land use change in the urban-rural fringe, but this relationship varies across different types of linear transnort infrastrncnlre.展开更多
In this paper, an approach to simulate the spatial dis- tribution of urban population is proposed using urban land use and population statistical data through the geographical information systems (GIS). Then, the spat...In this paper, an approach to simulate the spatial dis- tribution of urban population is proposed using urban land use and population statistical data through the geographical information systems (GIS). Then, the spatial population distribution of Urumqi as a case is simulated by the approach mentioned above and its varying patterns are analyzed by the raster population surface. As a result, producing raster population surface is more accurate and natural than the traditional choropleth map of population density. Concerning the spatial population distribution of Urumqi, the population density declines from south to north and the population distribution mainly presents "T-type", the population distribution presents multi-centre agglomeration and the population distribu- tion of the districts shows different features. The population den- sity varies significantly with the increase in the distance from central business district (CBD). Finally, it is found in this paper that the development history of districts, terrain and traffic road are main factors that have an influence Urumqi’s population dis- tribution. This paper tries to provide more accurate population data for the plan and management of urban land, traffic and public facilities in order to enrich the researches on urban population distribution.展开更多
Northeast China has been reported as having serious air pollution in China with increasing occurrences of severe haze epi- sodes. Changchun City, as the center of Northeast China, has longstanding industry and is an i...Northeast China has been reported as having serious air pollution in China with increasing occurrences of severe haze epi- sodes. Changchun City, as the center of Northeast China, has longstanding industry and is an important agricultural base. Additionally, Changchun City has a long winter requiring heating of buildings emitting pollution into the air. These factors contribute to the complex- ity of haze pollution in this area. In order to analyze the causes of heavy haze, surface air quality has been monitored from 2013 to 2015. By using satellite and meteorological data, atmospheric pollution status, spatio-temporal variations and formation have been analyzed. Results indicated that the air quality in 88.9% of days exceeding air quality index (AQI) level-1 standard (AQI 〉50) according to the National Ambient Air Quality Standard (NAAQS) of China. Conversely, 33.7% of the days showed a higher level with AQI 〉 100. Ex- treme haze events (AQI 〉 300) occurred frequently during agricultural harvesting period (from October 10 to November 10), intensive winter heating period (from Late-December to February) and period of spring windblown dust (April and May). Most daily concentra- tions of gaseous pollutants, i.e., NO2 (43.8 gg/m3), CO (0.9 mg/m3), SO2 (37.9 gg/m3), and 03 (74.9 gg/m3) were evaluated within level-1 concentration limits of NAAQS standards. However, particulate matter (PM2.5 and PMI0) concentrations (67.3 ~tg/m3and 115.2 ~g/m3, respectively) were significantly higher than their level-1 limits. Severe haze in spring was caused by offsite transported dust and windblown surface soil. Heavy haze periods during fall and winter were mainly formed by intensive emissions of atmospheric pollutants and steady weather conditions (i.e., low wind speed and inversion layer). The overlay emissions of widespread straw burning and coal combustion for heating were the dominant factors contributing to haze in autumn, while intensive coal burning during the coldest time was the primary component of total emissions. In addition, general emissions including automobile exhaust, road and construction dust, residential and industrial activities, have significantly increased in recent years, making heavy haze a more frequent occurrence. There- fore, both improved technological strategies and optimized pollution management on a regional scale are necessary to minimize emis- sions in specified seasons in Changchun City, as well as comprehensive control measures in Northeast China.展开更多
基金Under the auspices of Knowledge Innovation Program of Chines Academy of Sciences (No. KZCX2-SW-210-1)
文摘Character of population distribution is one of the focuses studied by urban geography. Using the fifth national census data as basic data and using areal interpolation method, this paper analyzes character of urban population dis- tribution of Shenyang City, Northeast China, in terms of three aspects of statistical character, spatial auto-correlation and spatial structure. Furthermore, this research analyzes the factors affecting the population distribution of the city. The main conclusions include: 1) There is an obvious structure character of population distribution in the grid with a grain of 300m, which is appropriate scale when researching population distribution in Shenyang City. 2) Urban population dis- tribution has the character of assembling while population density distribution takes on variability in Shenyang City. 3) Population density distribution shows spatial auto-correlation within 7.36km. Spatial heterogeneity of population density is low. 4) Urban center, population distribution barycenter and population density maximum points separate each other. Population density distribution has multi-cores character. 5) Layout of governments, primary schools, middle schools, colleges, hospitals and marketplaces affects population distribution directly. With the increase of distance to these factors, population density decreases as logarithm.
基金Under the auspices of Key Projects in the National Science&Technology Pillar Program During the Twelfth Five-year Plan Period(No.2012BAH28B02)
文摘To shed light on the general patterns and trends in urban sprawl research,and to provide reference for future study,bibliometric analysis and refined analysis are conducted for publications in this area from 1991 to 2011.The general publication output,the global geographical distribution of the authors,the funding and institutions involved,the research areas,and the source titles are analyzed and discussed.Scholars in the United States and China have produced most of the documents in urban sprawl and these two countries are also the largest contributors in terms of funding and institutions.′Environmental Sciences&Ecology′,′Urban Studies′,and′Geography′are the most common research areas,and the journal titled Urban Studies has contributed the most articles.Furthermore,the refined analyses on the 500 top-cited and most relevant publications have revealed that research on urban sprawl is closely associated with the categories of′Urban form and development′,′Land use/land development′and′environment/ecology/biology′.Conclusions are made with respect to the basic paradigm of research on urban sprawl.The multi-disciplinary research into urban sprawl are expected to be more diversified and integrated.
基金supported by the National Natural Science Foundation of China (No. 51478311)the Natural Science Foundation of Tianjin, China (No. 14JCQNJC07400)
文摘In this paper, the verticalseismic effects on tunnels are studied based on a classic mass–damper–spring model. An analyticaldiscrete modelof urban underground tunnels subjected to verticalearthquake excitations is proposed by considering the first verticalvibration mode. Taking a light railproject in Tianjin as an example, this study uses the proposed discrete modelto analyze the displacements of tunneland soilunder verticalearthquake excitations. The soildisplacement responses at different tunnellocations are analyzed with linear random vibration theory.The computationalcost is greatly reduced using the proposed model. It can be seen that different from the case of horizontalearthquakes, the displacement responses under verticalearthquake excitations keep growing after seismic acceleration reaches its peak for a short duration, and then,they begin to decay. The soils at different positions around the tunnels have large relative displacement under verticalearthquake excitations. Moreover, a finite-element modelis also established for displacement responses using ABAQUS.The comparison with the results of the finite-element modelshows that the results of the proposed discrete modelare available.
文摘From the angle of ecology,urban agg lomeration presents relevant types of landscape structure,which in-clude Patch,Corridor and Matrix.There are different landscape feature s and different problems in differen t development phases.This paper has put forward fi ve basic conditions for security pattern of landscape ecology of urban agglomeration,described quantitatively the featu res for landscape ecology in Wuxi,an d analyzed ecological background of spatial expan-sion and spatial organization of urb an development in Wuxi.From the angle of ecological land use and non-ecological land use,the paper has analyzed the featu res of land use and ecological distribution of land in the urban area.The s patial mod-el of cities and towns in Wuxi is composed of one metropolis,two urban zones and three development axes.This th esis has planned preliminarily ecologic al protection network at four levels in the urban region according to four layers.At last,combining landscape ecology with ur ban space,a tentative security pattern of landscape ecology has been pla nned in Wux-i,namely Source-Buffer Zone and Metropolis,Radiating Routes and Expan sion Direction of City,Strategic Point and Interac-tion between Cities and Towns,Inter-Source Linkage-Corridor of a Stabl e Landscape Structure.
文摘This paper raises the comparison method of operational stages of the real estate market. In order to select similar operational stages, we established an analysis model by applying fuzzy grade-of-membership clustering in this paper. Firstly, we select the materials information of the real estate market in America, Germany and Japan. Secondly, the real estate markets of America, Germany and Japan are divided into several different stages. Lastly, we apply the method of fuzzy grade-of-membership clustering to select comparable stages. The result of analysis indicates that the real estate market of Japan and Germany (1960-1980) are similar to the market in China.
基金the Young Scientist Fund of National Nature Science Foundation of China(No.41101148)
文摘Based on the National Land Use/Cover Database of China(NLUD-C) in the end of the 1980s(the 1980s,hereafter), 1995, 2000, 2005, and 2010, 665 cities were selected to study the size distribution and its changes of urban lands in China. In this study, the spatiotemporal evolutions of urban land size distribution as well as the influence of administrative-level on these cities were explored by combining urban spatial positions and administrative-levels. Results indicate that: 1) City size distribution using urban lands was more practical and reasonable than using non-agricultural population. 2) In the 1980s, cities with ascending urban land rank were centralized in Eastern China, specially the Changjiang(Yangtze) River Delta, the Zhujiang(Pearl) River Delta, and Beijing-Tianjin-Hebei region. Cities in Central, Western, and Northeast China mainly indicated descending urban land rank. 3) The transfer of national development focus resulted in cities with ascending urban land rank becoming evenly distributed nationwide; however, this trend was slightly centralized around Chengdu, Chongqing, and Wuhan in different periods. 4) During the 1980s to 2010, the proportion of cities with ascending urban land rank in provincial capitals, municipalities, and special administrative regions(high-level cities, hereafter) was consistently higher than those in prefecture- and county-level cities except for 2005–2010. The ranks of the majority of the prefecture- and county-level cities were mainly descending, supported by ascending; the proportion of cities with unchanged rank is small. This study breaks through the bottleneck of traditional research in the area of city size distribution by examining urban land replacing the non-agricultural population. The current study also provides scientific explanation for the healthy and reasonable development of urban land as well as the coordinated development of population urbanization and land urbanization.
基金Under the auspices of European Commission under 7th Framework Programme (No ECUBS–230824)
文摘The institutional environment in China has quite evidently changed during modern socio-economic transitions.Driven both by local government and by marketing force,urban social space was redistributed after the reform of urban land and real estate policies.Urban renewal makes for wide differential rent and therefore gentrification is occurring in China.This paper analyzes the background and institutional environment of gentrification in China,and further discusses the process,characteristics and evolutionary mechanisms in the case of Nanjing,through investigation of the attributes of 1075 residential communities built during the 1998-2008 at a macro level,and interviewing the residents and analyzing questionnaires in 6 different and typical communities at a micro level.As a socio-spatial course of two-way interaction,gentrification is divided into 3 stages of incubation,occurrence and fast development,according to the time of landmark events and policy reform on the leasehold of land in Nanjing during socio-economic transition.In terms of the socio-spatial characteristics of gentrification in Nanjing,the gentrification process under the trajectory of urban renewal makes urban social space present a new circle-layer structure;the rise of quite a number of gated communities results in the fragmentation of social space and privatization of public space;the management mode of modern communities and the change of life style have aggravated the indifference of neighborhood relationship of gentrified communities.Based on the empirical evidence of this study,this paper indicates that gentrification is quite different between China and western countries with respect to spatio-temporal order,dominant forces,paths of realization and spatial expression,and it further reveals the dynamic mechanism of gentrification developing in China at the present stage.
文摘The aim of this paper is to present the urban history of Juiz de Fora, a city with some 500,000 inhabitants in southeastern Brazil, and discuss how strategic decisions about the planning and construction of roads and highways can determine ways of life in a city. While paths may integrate landholdings and territories, they may also segregate communities and environments, causing deep rifts in the fabric of urban and land areas. The growth of Juiz de Fora is particularly marked by the construction of paths. This article reviews the local urban history from the establishment of paths in the city, to an analysis of the major impact and benefits they have had, notably on the local economy and demographics, as well as on the conservation of the local environment: Issues that are frequently relegated to a secondary role in the cost-benefit analysis of the city's planning decisions. After analysis of the case study, the authors concluded that citizens should be included on the agenda of the city, from spectators to actors of daily urban life.
基金supported by Funding of National Natural Science Foundation of China"Research on environmental risk assessment and management of the avoidance project based on perspective of public perception,""Research on the evolution mechanism of the avoidance cluster behavior by considering of endogenous information under the internet environment"[Grant Numbers 71671080,7157109]Funding of National Natural Science Youth Foundation of China"The formation,evolution and conflict coordination of the avoidance behavior"[Grant Number 71301070]+1 种基金Funding of National Statistical Science Research Project"Energy statistics and its balance sheet in China based on perspective of energy quality"[Grant Number 2016LZ36]Funding of Science Foundation of Huainan Normal University"Benefit evaluation of coal mining subsidence area comprehensive management based on external perspective"[Grant Number 2016xj07zd]
文摘Demographic urbanization caused great changes in scale of residents' consumption and residents' lifestyle and then impacted changes of regional household energy consumption. This paper expanded Logarithmic Mean Decomposition Index method through introducing variables of urbanization and residential consumption into the model. It also analyzed the influences of six factors as energy structure, energy intensity, population scale, urbanization, residential consumption, and consumption inhibit on regional household energy consumption. Results showed that in 2003-2012, impact of urbanization on regional household energy consumption of Chinese three areas was significantly higher than population size. The "population gathered in eastern region" phenomenon caused eastern region getting the largest population scale effect. Driving force of residential consumption on regional household energy consumption was much higher than the other five effects. Due to the comparative advantage of residential consumption compared with government consumption, investment, and net export, the decrease of consumption ratio promoted the growth of regional household energy consumption. Energy intensity in Chinese three regions kept reducing in 2003-2012. The progress of energy utilization technology slowed the growth of regional household energy consumption, and energy intensity effect was most significant in the central region.
文摘Construction of tunnels in urban areas requires assessment of the impact of tunneling on the stability and integrity of existing pile foundations. We have focused our attention to the analysis of the carrying capacity of pile foundations provided by the impact of construction of urban tunnels on adjacent pile foundations, under the engineering background of the construction of the # 2 Line of the Guangzhou subway. It is carried out using a fast Lagrangian analysis of a continuum in a 3D numerical code, which is an elastoplastic three-dimensional finite difference model, to simulate the response of piles under the entire process of metro tunneling (deactivation of soil element and activation of the lining). The adjacent stratum around the tunnel is classified into three regions: Zone Ⅰ (upper adjacent stratum of tunnel), Zone Ⅱ (45°-upper-lateral adjacent stratum of tunnel) and Zone Ⅲ (lateral adjacent stratum of tunnel). In each region one typical pile is chosen to be calculated and analyzed in detail. Numerical simulations are mainly conducted at three points of each pile shaft: the side-friction force of the pile, the tip resistance of the pile and the axial loading of the pile. A contrasting analysis has been conducted both in the response of typical piles in different regions and from computer calculated values with site monitoring values. The results of numerical simulations show that the impact on carrying capacity of the piles lies mainly in the impact of construction of urban tunnels on the side-friction forces and the tip resistance of piles. The impact differs considerably among the different strata zones where the pile tips are located. The complicated rules of side-friction force and tip resistance of piles has resulted in complicated rules of pile axial loading thus, in the end, it impacts the carrying capacity of pile-foundations. It is necessary to take positive measures, such as stratum grouting stabilization or foundation underpinning, etc, to deal with the carrying capacity and the settlement of pile-foundations. The results are of value to similar engineering projects.
文摘Following the Great East Japan Earthquake in March 2011, the demand for bottled water increased sharply. In this paper, the authors analyze who purchased more bottled water after the earthquake using Quick Purchase Report data. The results are as follows: first, consumers who before the earthquake tended to purchase less bottled water tended to increase the volume purchased after the earthquake; second, the motives for purchasing bottled water after the earthquake differed between consumers in the Tokyo and Osaka metropolitan districts.
基金Under the auspices of National Technology Research and Development Program of China(No.2006BAJ05A02)National Natural Science Foundation of China(No.31172023)
文摘Shadow is one of the major problems in remotely sensed imagery which hampers the accuracy of information extraction and change detection.In these images,shadow is generally produced by different objects,namely,cloud,mountain and urban materials.The shadow correction process consists of two steps:detection and de-shadowing.This paper reviews a range of techniques for both steps,focusing on urban regions(urban shadows),mountainous areas(topographic shadow),cloud shadows and composite shadows.Several issues including the problems and the advantages of those algorithms are discussed.In recent years,thresholding and recovery techniques have become important for shadow detection and de-shadowing,respectively.Research on shadow correction is still an important topic,particularly for urban regions(in high spatial resolution data) and mountainous forest(in high and medium spatial resolution data).Moreover,new algorithms are needed for shadow correction,especially given the advent of new satellite images.
基金supported by the National Hi-tech Research and Development Program of China(No. 2009AA12Z147)the Postdoctorial Foundation of China(No.20090451339)+2 种基金the Postdoctorial Foundation of Shandong Province(No.200802013)Soft Science Project of Shandong Province(No.2007 RKA071)this research is also supported by Qingdao Economic & Technical Developing District Project (No.2008-2-26).
文摘The geochemical baseline is the fundamental reference for environmental change and assessment.In this article we describe cluster and regression analyses with a normalization procedure.The elements Sc and Ag were chosen to calculate the environmental geochemical baseline.The geoaccumulation index was calculated and mapped to indicate the environmental quality of the soil.The results show that the urban areas are barely polluted with Ni and Cr but the rural areas in the southern part of the city, and the western part of the lake,are polluted with Ni,Cr,and Cu at the second level.On the other hand,the rural areas in the southern part of the city,and the western part of the lake,are polluted with As at a moderate level.The other area is polluted at the second level.An increase in As pollution occurs in a direction from northeast to southwest.The Cd pollution follows a trend similar to As,with an additional smaller contaminated area polluted at levelⅢ.The Hg pollution typical of urban areas occurs in the main and northern parts of the city.The geochemical accumulation index decreases from the city center to the periphery.The highest pollution level reaches levelⅣ,which indicates that the soil is seriously polluted with Hg.The southern part of the city and the rural areas to the west of the lake are not contaminated with Hg.Geological factors and the disturbance from human activities are both possible major factors:further research is needed to identify them.
文摘According to the Chinese GB50011-2001 code and the recommended provisions of FEMANEHRP and EUROCODE 8, by using shear wave velocity and borehole data, the site classification is evaluated for a typical soft soil site on the Yantai seacoast. The site seismic ground motion effect is analyzed and the influence of the coastal soil on design ground motion parameters is discussed. The results show that the brief site classification can not represent the real conditions of a soft soil site; the soft soil on the coast has a remarkable impact on the magnitude and spectrum of ground motion acceleration. The magnification on peak acceleration is bigger, however, due to the nonlinear deformation of the soil. The magnification is reduced noulinearly with the increase of input ground motion; the spectrum is broadened and the characteristic period elongated on the soft soil site.
基金Under the auspices of National Natural Science Foundation of China(No.41001314)Youth Science Funds of State Key Laboratory of Resources and Environmental Information System,Chinese Academy of Sciences(No.KA11040101)National Key Technology R&D Program of China(No.2012BAI32B07)
文摘Existing quantitative migration studies are mainly at the inter-region or inter-province level for lacking of detailed geo-referenced migration data.Meanwhile,few of them integrate explorative spatial data analysis and spatial regression model into migration analysis.Based on aggregated registered floating population data from 2005 to 2008,the phenomena that population floating to Yiwu City in Zhejiang Province is analyzed at the provincial and county levels.The spatial layout of Yiwu's pull forces is proved as a V-shaped pattern excluding Sichuan Province based on map visualization method.Using the migration ratio in 2007 as an explanatory variable,two models are compared using ordinary least square,spatial error model and spatial lag model methods for county-level data in Jiangxi and Anhui provinces.The model with migration stock provides an improved fitting over the model without migration stock according to the model fitting results.The floating population flocking into Yiwu City from Jiangxi is determined mostly by migration stock while the determinant factors are migration stock and distance to Yiwu City for Anhui.The distance-decay effect is true for migration flow from Anhui to Yiwu City while the distance rule is not confirmed in Jiangxi with the best fitting model.The correlation between per capita net income of rural labor forces and migration ratio is not significant in Jiangxi and significant but at the 0.1 level only in Anhui.Further analysis shows that the distance,income and man-land ratio are important factors to explain population floating at earlier stage.However,as the dynamic population floating process evolves,the determinant factor would be migration stock.
基金Under the auspices of National Science&Technology Pillar Program during the Eleventh Five-year Plan Period(No.2008BAJ10B1)
文摘This paper principally focuses on land use dynamics,urban expansion and underlying driving forces in the Natural Wetland Distribution Area(NWDA)of Fuzhou City in the southeastern China.Based on time series Landsat TM/ETM+imageries and historical data,relationships between urban land expansion and its influencing factors from 1989 to 2009 were analyzed by using an integrated approach of remote sensing(RS)and geographic information system(GIS)techniques.The results showed that built-up land increased from 151.16 km2in 1989 to 383.76 km 2in 2009. Approximately 64.25%of the newly emerging built-up land was converted from cropland(29.47%),forest and shrub (25.78%),water(3.73%),wetland(4.61%),and bare land(0.66%)during 1989 and 2009.With a remarkable decrease in cropland,the proportion of non-agricultural population increased by 23.6%.Moreover,rapid development of infrastructures,facilities,industrial parks,and urban and rural settlements along the Minjiang River resulted in the eastward and southward expansion of built-up land.Additionally,the growth pattern of built-up land in the NWDA is highly correlated with socio-economic factors,including the gross domestic product(GDP),GDP per capita,and structure of industry.As a result,the observed environmental degradation such as loss of cropland and wetland due to heavy pressure of rapid urbanization have greatly impaired the carrying capacity of city.Thus,in addition to scientific and rational policies towards minimizing the adverse effects of urbanization,coordination between the administrative agencies should be urgently strengthened to balance the conflicts between urban development and ecological conservation to make sure the sustainable land use.
基金Under the auspices of National Natural Science Foundation of China(No.40871255)Scientific Research Foundation of Graduate School of Nanjing University(No.2010CL12)
文摘Integrated transportation and land use studies are of major interest to planners because they consider the interaction between transportation development and land use change. Quantifying the impact of transport infrastructure on land use change is necessary for evaluating the role of transportation development in the process of land use and land cover change in the urban-rural fringe. Taking Qixia District of Nanjing City, Jiangsu Province, China as a typical urban-rural fringe area, this paper analyzes the patterns and charac- teristics of land use change along three major transportation arteries using land use data from 2000 and 2008. We examine the spatial differentiation and gradient of land use pattern around railway, expressway, and highway corridors to investigate whether land use change in the urban-rural fringe is related to distance from transportation arteries and to clarify the varying impacts of different forms of transport infrastructure on land use patterns. We find that construction land generally tends to be located close to major transportation arteries, and that railways have the most obvious influence on land use change in the urban-rural fringe, while the impact of expressways was not significant. We conclude that there exists a causal relationship between the presence of transportation arteries and land use change in the urban-rural fringe, but this relationship varies across different types of linear transnort infrastrncnlre.
基金This study is supported by the Knowledge Innovation Project of CAS (Grant No. KZCS-SW-355).
文摘In this paper, an approach to simulate the spatial dis- tribution of urban population is proposed using urban land use and population statistical data through the geographical information systems (GIS). Then, the spatial population distribution of Urumqi as a case is simulated by the approach mentioned above and its varying patterns are analyzed by the raster population surface. As a result, producing raster population surface is more accurate and natural than the traditional choropleth map of population density. Concerning the spatial population distribution of Urumqi, the population density declines from south to north and the population distribution mainly presents "T-type", the population distribution presents multi-centre agglomeration and the population distribu- tion of the districts shows different features. The population den- sity varies significantly with the increase in the distance from central business district (CBD). Finally, it is found in this paper that the development history of districts, terrain and traffic road are main factors that have an influence Urumqi’s population dis- tribution. This paper tries to provide more accurate population data for the plan and management of urban land, traffic and public facilities in order to enrich the researches on urban population distribution.
基金Under the auspices of National Key Research and Development Project(No.2017YFC0212300)Youth Innovation Promotion Association CAS(No.2017275)Frontier Science Research Plan CAS(No.QYZDB-SSW-DQC045)
文摘Northeast China has been reported as having serious air pollution in China with increasing occurrences of severe haze epi- sodes. Changchun City, as the center of Northeast China, has longstanding industry and is an important agricultural base. Additionally, Changchun City has a long winter requiring heating of buildings emitting pollution into the air. These factors contribute to the complex- ity of haze pollution in this area. In order to analyze the causes of heavy haze, surface air quality has been monitored from 2013 to 2015. By using satellite and meteorological data, atmospheric pollution status, spatio-temporal variations and formation have been analyzed. Results indicated that the air quality in 88.9% of days exceeding air quality index (AQI) level-1 standard (AQI 〉50) according to the National Ambient Air Quality Standard (NAAQS) of China. Conversely, 33.7% of the days showed a higher level with AQI 〉 100. Ex- treme haze events (AQI 〉 300) occurred frequently during agricultural harvesting period (from October 10 to November 10), intensive winter heating period (from Late-December to February) and period of spring windblown dust (April and May). Most daily concentra- tions of gaseous pollutants, i.e., NO2 (43.8 gg/m3), CO (0.9 mg/m3), SO2 (37.9 gg/m3), and 03 (74.9 gg/m3) were evaluated within level-1 concentration limits of NAAQS standards. However, particulate matter (PM2.5 and PMI0) concentrations (67.3 ~tg/m3and 115.2 ~g/m3, respectively) were significantly higher than their level-1 limits. Severe haze in spring was caused by offsite transported dust and windblown surface soil. Heavy haze periods during fall and winter were mainly formed by intensive emissions of atmospheric pollutants and steady weather conditions (i.e., low wind speed and inversion layer). The overlay emissions of widespread straw burning and coal combustion for heating were the dominant factors contributing to haze in autumn, while intensive coal burning during the coldest time was the primary component of total emissions. In addition, general emissions including automobile exhaust, road and construction dust, residential and industrial activities, have significantly increased in recent years, making heavy haze a more frequent occurrence. There- fore, both improved technological strategies and optimized pollution management on a regional scale are necessary to minimize emis- sions in specified seasons in Changchun City, as well as comprehensive control measures in Northeast China.