scholarly journals Fractal-Based Modeling and Spatial Analysis of Urban Form and Growth: A Case Study of Shenzhen in China

2020 ◽  
Vol 9 (11) ◽  
pp. 672
Author(s):  
Xiaoming Man ◽  
Yanguang Chen
Keyword(s):  
Fractal Dimension ◽  
Urban Growth ◽  
Urban Form ◽  
Fractal Structure ◽  
Southern China ◽  
Growth Curves ◽  
Northern China ◽  
Logistic Function ◽  
Urban Region ◽  
The Common

Fractal dimension curves of urban growth can be modeled with sigmoid functions, including logistic function and quadratic logistic function. Different types of logistic functions indicate different spatial dynamics. The fractal dimension curves of urban growth in Western countries follow the common logistic function, while the fractal dimension growth curves of cities in northern China follow the quadratic logistic function. Now, we want to investigate whether other Chinese cities, especially cities in South China, follow the same rules of urban evolution and attempt to analyze the reasons. This paper is devoted to exploring the fractals and fractal dimension properties of the city of Shenzhen in southern China. The urban region is divided into four subareas using ArcGIS technology, the box-counting method is adopted to extract spatial datasets, and the least squares regression method is employed to estimate fractal parameters. The results show that (1) the urban form of Shenzhen city has a clear fractal structure, but fractal dimension values of different subareas are different; (2) the fractal dimension growth curves of all the four study areas can only be modeled by the common logistic function, and the goodness of fit increases over time; (3) the peak of urban growth in Shenzhen had passed before 1986 and the fractal dimension growth is approaching its maximum capacity. It can be concluded that the urban form of Shenzhen bears characteristics of multifractals and the fractal structure has been becoming better, gradually, through self-organization, but its land resources are reaching the limits of growth. The fractal dimension curves of Shenzhen’s urban growth are similar to those of European and American cities but differ from those of cities in northern China. This suggests that there are subtle different dynamic mechanisms of city development between northern and southern China.

scholarly journals Modeling Urban Growth and Form with Spatial Entropy

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Yanguang Chen
Keyword(s):  
Fractal Dimension ◽  
Urban Growth ◽  
Urban Form ◽  
Growth Models ◽  
Logistic Function ◽  
Measurement Scale ◽  
Spatial Complexity ◽  
Entropy Increase ◽  
Fractal Models ◽  
Spatial Entropy

Entropy is one of the physical bases for the fractal dimension definition, and the generalized fractal dimension was defined by Renyi entropy. Using the fractal dimension, we can describe urban growth and form and characterize spatial complexity. A number of fractal models and measurements have been proposed for urban studies. However, the precondition for fractal dimension application is to find scaling relations in cities. In the absence of the scaling property, we can make use of the entropy function and measurements. This paper is devoted to researching how to describe urban growth by using spatial entropy. By analogy with fractal dimension growth models of cities, a pair of entropy increase models can be derived, and a set of entropy-based measurements can be constructed to describe urban growing process and patterns. First, logistic function and Boltzmann equation are utilized to model the entropy increase curves of urban growth. Second, a series of indexes based on spatial entropy are used to characterize urban form. Furthermore, multifractal dimension spectra are generalized to spatial entropy spectra. Conclusions are drawn as follows. Entropy and fractal dimension have both intersection and different spheres of application to urban research. Thus, for a given spatial measurement scale, fractal dimension can often be replaced by spatial entropy for simplicity. The models and measurements presented in this work are significant for integrating entropy and fractal dimension into the same framework of urban spatial analysis and understanding spatial complexity of cities.

scholarly journals Exploring the Fractal Parameters of Urban Growth and Form with Wave-Spectrum Analysis

2010 ◽  
Vol 2010 ◽  
pp. 1-20 ◽  
Author(s):  
Yanguang Chen
Keyword(s):  
Fractal Dimension ◽  
Urban Growth ◽  
Urban Form ◽  
Wave Spectrum ◽  
Fractal Dimensions ◽  
Wave Number ◽  
Similar Distribution ◽  
Image Dimension ◽  
Radial Dimension ◽  
The Fourier Transform

The Fourier transform and spectral analysis are employed to estimate the fractal dimension and explore the fractal parameter relations of urban growth and form using mathematical experiments and empirical analyses. Based on the models of urban density, two kinds of fractal dimensions of urban form can be evaluated with the scaling relations between the wave number and the spectral density. One is theradial dimensionof self-similar distribution indicating the macro-urban patterns, and the other, the profile dimension of self-affine tracks indicating the micro-urban evolution. If a city's growth follows the power law, the summation of the two dimension values may be a constant under certain condition. The estimated results of the radial dimension suggest a new fractal dimension, which can be termed “image dimension”. A dual-structure model namedparticle-ripple model(PRM) is proposed to explain the connections and differences between the macro and micro levels of urban form.

scholarly journals Insights from a joint analysis of Indian and Chinese monsoon rainfall data

2011 ◽  
Vol 15 (8) ◽  
pp. 2709-2715 ◽  
Author(s):  
M. Zhou ◽  
F. Tian ◽  
U. Lall ◽  
H. Hu
Keyword(s):  
Large Scale ◽  
Monsoon Rainfall ◽  
Indian Monsoon ◽  
Southern China ◽  
Principal Component ◽  
Northern China ◽  
Rainfall Data ◽  
Joint Analysis ◽  
Climate Indices ◽  
The Common

Abstract. Monsoon rainfall is of great importance for agricultural production in both China and India. Understanding the features of the Indian and Chinese monsoon rainfall and its long term predictability is a challenge for research. In this paper Principal Component Analysis (PCA) method was adopted to analyze Indian monsoon and Chinese monsoon separately as well as jointly during the period 1951 to 2003. The common structure of Indian monsoon and Chinese monsoon rainfall data was explored, and its correlation with large scale climate indices and thus the possibility of prediction were analyzed. The joint PCA results gives a clearer correlation map between Chinese monsoon rainfall and Indian monsoon rainfall. The common rainfall structure presents a significant teleconnection to Sea Surface Temperature anomaly (SSTa), moisture transport and other climate indices. Specifically, our result shows that Northern China would garner less rainfall when whole Indian rainfall is below normal, and with cold SSTa over the Indonesia region more rainfall would be distributed over India and Southern China. The result also shows that SSTa in the previous winter months could be a good indicator for the summer monsoon rainfall in China.

scholarly journals Urban Form Dynamics and Modelling towards Sustainable Hinterland Development in North Cianjur, Jakarta–Bandung Mega-Urban Region

2022 ◽  
Vol 14 (2) ◽  
pp. 907
Author(s):  
Anoraga Jatayu ◽  
Izuru Saizen ◽  
Ernan Rustiadi ◽  
Didit Okta Pribadi ◽  
Bambang Juanda
Keyword(s):  
Urban Growth ◽  
Urban Form ◽  
Urban Region ◽  
Urban Containment ◽  
Result Show ◽  
Rural Zone ◽  
Landscape Dynamic ◽  
Business As Usual ◽  
Land Change Modeling ◽  
Planning Intervention

The urban form is the physical configuration of a city, developed over time and space. Urban form can be considered at different scales, from region to neighborhood, each carrying a different focus. North Cianjur serves as the hinterland and one of the conurbation corridors of the Jakarta–Bandung Mega-Urban Region, meaning that the balance between its function as an environmental buffer area and the destination of urban growth needs to be planned carefully. This paper explores the dynamics in North Cianjur and employs several model scenarios as a planning intervention using landscape dynamic tools and land-change modeling, with three scenarios employed: Business as Usual (BAU), Spatial Planning Policy (SPP), and Urban Containment (UCT). The result show that North Cianjur has transformed into a polycentric region with two urban zones, a peri-urban zone, and a rural zone in the northernmost part of the region. Urban form trends show a sprawling built-up pattern outside urban zones, and a compacted trend in urban zones due to expansion from the Jakarta and Bandung Metropolitan Area. UCT models appear to be the most optimal for implementation in North Cianjur, representing a way to accommodate urban growth and expansion inside the urban center while still maintaining regional sustainability.

scholarly journals LOGISTIC MODELS OF FRACTAL DIMENSION GROWTH OF URBAN MORPHOLOGY

Fractals ◽  
2018 ◽  
Vol 26 (03) ◽  
pp. 1850033 ◽  
Author(s):  
YAN-GUANG CHEN
Keyword(s):  
Fractal Dimension ◽  
Urban Form ◽  
Missing Values ◽  
Logistic Models ◽  
Developed Countries ◽  
Logistic Function ◽  
Urban Morphology ◽  
City Development ◽  
Spatial Form ◽  
The Developed Countries

Urban form can be described with fractal dimension, which is a measurement of space filling of urban evolution. However, how to model and understand the fractal dimension growth of urban morphology are still pending questions. This paper is devoted to the research on the fractal dimension curves of urban growth. The principle of squashing function and empirical evidences are employed to demonstrate the following inference: the fractal dimension time series of a city’s spatial form take on a sigmoid curve. Among various sigmoid functions, the logistic function is the most probable selection. The observational data of fractal dimension of different cities from different sources support this logic judgment. A further discovery is that the fractal dimension curves of cities in the developed countries differ from those in the developing countries. A generalized logistic function is thus proposed to model the fractal dimension curves of different types of cities. The general logistic models can be used to predict the missing values and estimate the growth rates of fractal dimension of city development. Moreover, these models can be utilized to analyze when and where there is a fractal of urban form.

Spatial variation of East Asian winter monsoon evolution between northern and southern China since the last glacial maximum

2021 ◽  
pp. 1-14
Author(s):  
Qin Li ◽  
Haibin Wu ◽  
Jun Cheng ◽  
Shuya Zhu ◽  
Chunxia Zhang ◽  
...  
Keyword(s):  
East Asian Winter Monsoon ◽  
Southern China ◽  
Ice Sheets ◽  
Northern China ◽  
Winter Monsoon ◽  
Asian Winter Monsoon ◽  
Spatial Differences ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Abstract The East Asian winter monsoon (EAWM) is one of the most dynamic components of the global climate system. Although poorly understood, knowledge of long-term spatial differences in EAWM variability during the glacial–interglacial cycles is important for understanding the dynamic processes of the EAWM. We reconstructed the spatiotemporal characteristics of the EAWM since the last glacial maximum (LGM) using a comparison of proxy records and long-term transient simulations. A loess grain-size record from northern China (a sensitive EAWM proxy) and the sea surface temperature gradient of an EAWM index in sediments of the southern South China Sea were compared. The data–model comparison indicates pronounced spatial differences in EAWM evolution, with a weakened EAWM since the LGM in northern China but a strengthened EAWM from the LGM to the early Holocene, followed by a weakening trend, in southern China. The model results suggest that variations in the EAWM in northern China were driven mainly by changes in atmospheric carbon dioxide (CO2) concentration and Northern Hemisphere ice sheets, whereas orbital insolation and ice sheets were important drivers in southern China. We propose that the relative importance of insolation, ice sheets, and atmospheric CO2 for EAWM evolution varied spatially within East Asia.

scholarly journals The Geographical Distribution and Correlates of Pro-Environmental Attitudes and Behaviors in an Urban Region

Energies ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1540 ◽  
Author(s):  
Áróra Árnadóttir ◽  
Michał Czepkiewicz ◽  
Jukka Heinonen
Keyword(s):  
Urban Form ◽  
Online Survey ◽  
Environmental Concern ◽  
International Travel ◽  
Urban Region ◽  
Environmental Attitude ◽  
Environmental Behaviors ◽  
Household Energy ◽  
Carbon Footprints ◽  
Current Perspective

A lot of emphasis has been put on the densification of urban form to reduce greenhouse gas emissions from transportation. However, many recent studies have found that central urban dwellers, even though their carbon footprints of daily transportation may be lower, might be responsible for higher total emissions than those that reside in suburban areas. Similarly, as with the urban form, higher environmental concern is often considered as an indicator of lower emissions, but several studies have found that pro-environmental attitude (PEA) does not always correlate with less energy intensive behavior. This study analyzes how urban zones, PEA, and several sociodemographic variables are associated with annual travel emissions and pro-environmental behaviors (PEB), using a dataset collected with a map-based online survey (softGIS) survey, contributed by 841 participants from the Helsinki Metropolitan Area (HMA), Finland. Although PEA can affect PEBs related to household energy consumption (β = 0.282, p < 0.001), clothing (β = 0.447, p < 0.001) and produce purchases (β = 0.449, p < 0.0001), their relationship with emissions from local (β = −0.067), national (β = −0.019) and international (β = −0.016) travel was not significant. Clusters of low emissions from local travel and high international travel emissions were found in pedestrian-oriented urban zones and residents of car-oriented zones were more likely to conserve household energy (β = 0.102, p < 0.05). These results might help broaden the current perspective of city planners, as well as identify opportunities for more effective mitigation policies.

scholarly journals Development of revised diagnostic criteria for Fuchs’ uveitis syndrome in a Chinese population

2021 ◽  
pp. bjophthalmol-2021-319343
Author(s):  
Peizeng Yang ◽  
Wanyun Zhang ◽  
Zhijun Chen ◽  
Han Zhang ◽  
Guannan Su ◽  
...  
Keyword(s):  
Diagnostic Criteria ◽  
Clinical Symptoms ◽  
Southern China ◽  
High Sensitivity ◽  
Northern China ◽  
Chinese Patients ◽  
Tertiary Referral Centre ◽  
Tree Algorithms ◽  
Vitreous Opacities ◽  
Fuchs Uveitis Syndrome

Background/aimsFuchs’ uveitis syndrome (FUS) is one of the frequently misdiagnosed uveitis entities, which is partly due to the absence of internationally recognised diagnostic criteria. This study was performed to develop and evaluate a set of revised diagnostic criteria for FUS.MethodsThe clinical data of Chinese patients with FUS and patients with non-FUS were collected and analysed from a tertiary referral centre between April 2008 and December 2020. A total of 593 patients with FUS and 625 patients with non-FUS from northern China were enrolled for the development of diagnostic criteria for FUS. Three hundred and seventy-seven patients with FUS and 503 patients with non-FUS from southern China were used to validate the criteria. Clinical symptoms and ocular signs were collected from all patients with FUS and patients with non-FUS. Multivariate two-step cluster analysis, logistic regression and decision tree algorithms in combination with the clinical judgement of uveitis experts were used to revise diagnostic criteria for FUS.ResultsThree essential findings including diffuse iris depigmentation, absence of posterior synechiae, mild inflammation in the anterior chamber at presentation and five associated findings including mostly unilateral involvement, cataract, vitreous opacities, absence of acute symptoms and characteristic iris nodules were used in the development of FUS diagnostic criteria. All essential findings were required for the diagnosis of FUS, and the diagnosis was further strengthened by the presence of associated findings.ConclusionRevised diagnostic criteria for FUS were developed and validated by analysing data from Chinese patients and showed a high sensitivity (96.55%) and specificity (97.42%).

Comparative Analysis of Nutritional Quality of Dendrobium Officinale Kimura Et Migo After Transplantation of Artificially Cultivated Plants From South to North China During Different Growing Years

2021 ◽  
Author(s):  
Xiaohui Guo ◽  
Shijing Zhang ◽  
Ting Yan ◽  
Guoqiang Yuan ◽  
Yafeng Dai ◽  
...  
Keyword(s):  
Nutritional Quality ◽  
Southern China ◽  
Northern China ◽  
Habitat Destruction ◽  
Dendrobium Officinale ◽  
Cultivated Plants ◽  
Total Phenolic ◽  
The Third ◽  
Nutritional Compounds ◽  
Nutrient Profiles

Abstract Background: Dendrobium officinale Kimura et Migo is a traditional functional food and medicinal plant in China. Due to low natural regeneration rates, habitat destruction, excessive collection and commercial trade, D. officinale is severely threatened, and commercial artificial-sheltered cultivation has been massively used to meet the needs of the market. Aim: To comprehensively compare the accumulation of nutritional compounds during 3-5 years of introduced, artificial-sheltered cultivation from southern to northern China.Methods: D. officinale of the same species were artificially cultivated in the southern traditional cultivation area, Anhui and the new northern cultivation area, Beijing. First, samples were collected in the third, fourth, and fifth years of growth, and nutritional quality indexes, including polysaccharides, alkaloids, flavonoids and total phenolic content, were determined. Second, an untargeted metabolomics method was used to investigate metabolic variations in D. officinale stems between Anhui and Beijing cultures in the fifth year.Results: After comparing the nutrient accumulation in different growing years, the idea harvest time was found in the third growing year in both cultivation areas. Of them, the contents of polysaccharides, flavonoids and total polyphenol were higher in cultivation in Anhui than Beijing, but the accumulation of alkaloid content was much lower in Anhui. The highest amount of polysaccharides of Dendrobium officinale was found in the three-year cultivation in Anhui, which reached 515.75 mg/g. When metabolites were analysed, a total of 272 metabolites were detected in the current study, including 27 up-regulated and 73 down-regulated metabolites in D. officinale cultivated in Beijing compared with samples from Anhui. Conclusion: D. officinale artificially and transplanted cultivated from southern to northern China showed some significant differences in the accumulation of nutrient compounds. Planting in northern China has some specific advantages, but the overall nutritional value is not as good as planting in southern China. Our study contributes to a better understanding of the nutrient profiles of D. officinale through artificial cultivation in different areas.

Sign in / Sign up

Export Citation Format

Share Document