• Title/Summary/Keyword: Urban Morphology

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Analysis of River Channel Morphology and Riparian Land Use Changes Using Aerial Photographs and GIS

  • Park Geun Ae;Lee Mi Seon;Kim Hyeon Jun;Kim Seong Joon
    • Proceedings of the KSRS Conference
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    • 2004.10a
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    • pp.566-569
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    • 2004
  • This study is to trace the change of stream shape using the past series of aerial photographs, and to compare the land use changes of riparian area along the stream. For the Gyeongan national stream, aerial photographs of 1966, 1981 and 2000 were selected and ortho photographs were made with interior orientation and exterior orientation, respectively. As apparent changes of the stream, the consolidated reaches of stream with levee construction were straightened and their stream widths were widened. Especially the stream width of inlet part of Paldang lake was widened almost twice because of the rise of water level by dam construction in 1974. The land use maps (1966, 1981,2000) of riparian areas were also made, respectively and classified into 6 categories (water, forest, agricultural land, urban area, road, sandbar) by digitizing. The area of forest and agricultural land decreased and urban area increased as the stream maintenance was performed.

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Filtering of Lidar Data using Labeling and RANSAC Algorithm (Labeling과 RANSAC알고리즘을 이용한 Lidar 데이터의 필터링)

  • Lee, Jeong-Ho;Kim, Yong-Il
    • Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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    • 2010.04a
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    • pp.267-270
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    • 2010
  • In filtering of urban lidar data, low outliers or opening underground areas may cause errors that some ground points are labelled as non-ground objects. To solve such a problem, this paper proposes an automated method which consists of RANSAC algorithm, one-dimensional labeling, and morphology filter. All processes are conducted along the lidar scan line profile for efficient computation. Lidar data over Dajeon, Korea is used and the final results are evaluated visually. It is shown that the proposed method is quite promising in urban dem generation.

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Comparison of Health Status of Japanese Tree Frog (Hyla Japonica) in a Rural and an Urban Area (농촌과 도시 지역에 서식하는 청개구리 (Hyla japonica)의 건강도 비교)

  • Park, So Hyun;Cho, Kang-Hyun
    • Ecology and Resilient Infrastructure
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    • v.4 no.1
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    • pp.71-74
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    • 2017
  • Urbanization is a major driver of global amphibian declines. For the study on the effect of urbanization on amphibians, we compared the growth and the health status of Hyla japonica amphibians collected in the urban areas of Incheon and in the rural area of Gapyeong, Korea. The size and weight of Hyla japonica body in the urban area were smaller than those in the rural area. However, there was no significant difference in their condition factors as a health indicator between the two areas. Our study emphasizes the need for research into the specific mechanism of effects of urbanization on amphibian heath status for the further understanding of the relationship between urbanization and amphibians.

Wind-induced fragility assessment of urban trees with structural uncertainties

  • Peng, Yongbo;Wang, Zhiheng;Ai, Xiaoqiu
    • Wind and Structures
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    • v.26 no.1
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    • pp.45-56
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    • 2018
  • Wind damage of urban trees arises to be a serious issue especially in the typhoon-prone areas. As a family of tree species widely-planted in Southeast China, the structural behaviors of Plane tree is investigated. In order to accommodate the complexities of tree morphology, a fractal theory based finite element modeling method is proposed. On-site measurement of Plane trees is performed for physical definition of structural parameters. It is revealed that modal frequencies of Plane trees distribute in a manner of grouped dense-frequencies; bending is the main mode of structural failure. In conjunction with the probability density evolution method, the fragility assessment of urban trees subjected to wind excitations is then proceeded. Numerical results indicate that small-size segments such as secondary branches feature a relatively higher failure risk in a low wind level, and a relatively lower failure risk in a high wind level owing to windward shrinks. Besides, the trunk of Plane tree is the segment most likely to be damaged than other segments in case of high winds. The failure position tends to occur at the connection between trunk and primary branches, where the logical protections and reinforcement measures can be implemented for mitigating the wind damage.

Genesis of a Vertical City in Hong Kong

  • Lau, Stephen S.Y.;Zhang, Qianning
    • International Journal of High-Rise Buildings
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    • v.4 no.2
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    • pp.117-125
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    • 2015
  • A vertical city with multifunctional land use turns out to be the most viable solution for an urban condition characterized by increasing density due to population expansion, topographical limitation of buildable land, economic development and the pursuit for collective sustainable living, such as in Hong Kong. This paper presents initial research results from a study on the chronological and typological evolution of tall buildings in the city, from the climate-responsive verandah typology to the mixed-use hyper-commercial podium and residential tower typologies that predominate today, to the ultimate formation of a vertical city. Case studies and surveys have focused on the development of this building typology throughout the decades since the 1920s, substantiating a discussion on the subjective and objective factors contributing to a genesis of the vertical city phenomenon in Hong Kong. The discussion will engage, under the notion of the vertical city, on how residents and visitors adapt to the growing density of the city, and how they accustom themselves to the changing urban morphology over time. Advantages such as high efficiency, spaces savings, time convenience, etc.; and disadvantages such as deficiency in livability, incompatibility of uses, environmental health deficiencies, etc.; serve as a reference for other cities in need of high-density planning due to population and economic growth.

Relationship between the Spatial Allocation of Developed Area and the Heat Wave Phenomenon: The Case of Five Metropolitan Cities (시가화지역 공간상 위치분배와 폭염현상과의 관계성: 5개 광역시 사례)

  • Kang, Sangjun
    • Journal of Environmental Impact Assessment
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    • v.30 no.3
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    • pp.175-185
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    • 2021
  • To better understand the heat wave phenomenon in the urban areas, it is desirable to explore the relationship between spatial allocation of land use and the heat wave. The purpose of this paper is to investigate the ranking correlation between heat wave days and developed types, specifically, core and islet developments. The methods employed are morphological spatial pattern, spatial autocorrelation, and spearman ranking correlation analyses by using the 30-year annual heat wave day records forthe five metropolitans. This research indicates that a fragmented development pattern including islets has mostly negative effects to the urban heat wave phenomenon. It means there is a relation between development pattern and heat wave.

Classification of Metro Station Areas Using Multi-Source Big Data: Case Studies in Beijing

  • Shuo Chen;Xiangyu Li
    • International Journal of High-Rise Buildings
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    • v.12 no.1
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    • pp.63-74
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    • 2023
  • Large-capacity public transportation systems, represented by urban metro lines, are the key to alleviating the significant increase in urbanization and motorization in China. But to improve the agglomeration effect of metro stations in a more accurate and targeted way requires scientific evaluation and classification of the surrounding areas of metro stations. As spatial and functional design are the core factors for urban renewal design, this study took Beijing as an example, using multi-source data to evaluate the morphology and functional composition surrounding areas of metro stations, and the Boston Consulting Group (BCG) matrix was used to classify and characterize each type of surrounding areas from morphological-functional dimensions. It shows a negative correlation of the mix-use index with the floor area ratio, and only about 20% of the areas achieve the ideal situation of high construction intensity with high mix-use diversity. Hoping to provide a reference for city managers and designers in dealing with the surrounding metro stations with different construction intensities in a more precise way.

Comprehensive Comparisons among LIDAR Fitering Algorithms for the Classification of Ground and Non-ground Points (지면.비지면점 분류를 위한 라이다 필터링 알고리즘의 종합적인 비교)

  • Kim, Eui-Myoung;Cho, Du-Young
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.30 no.1
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    • pp.39-48
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    • 2012
  • Filtering process that separates ground and non-ground points from LIDAR data is important in order to create the digital elevation model (DEM) or extract objects on the ground. The purpose of this research is to select the most effective filtering algorithm through qualitative and quantitative analysis for the existing filtering method used to extract ground points from LIDAR data. For this, four filtering methods including Adaptive TIN(ATIN), Perspective Center-based filtering method(PC), Elevation Threshold with Expand Window(ETEW) and Progressive Morphology(PM) were applied to mountain area, urban area and the area where building and mountains exist together. Then the characteristics for each method were analyzed. For the qualitative comparison of four filtering methods used for the research, visual method was applied after creating shaded relief image. For the quantitative comparison, an absolute comparison was conducted by using control points observed by GPS and a relative comparison was conducted by the digital elevation model of the National Geographic Information Institute. Through the filtering experiment of the LIDAR data, the Adaptive TIN algorithm extracted the ground points in mountain area and urban area most effectively. In the area where buildings and mountains coexist, progressive morphology algorithm generated the best result. In addition, as a result of qualitative and quantitative comparisons, the applicable filtering algorithm regardless of topographic characteristics appeared to be ATIN algorithm.

A "Dynamic Form-Finding" Approach to Environmental-Performance Building Design

  • Yao, Jia-Wei;Lin, Yu-Qiong;Zheng, Jing-Yun;Yuan, Philip F.
    • International Journal of High-Rise Buildings
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    • v.7 no.2
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    • pp.145-151
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    • 2018
  • Newly-designed high-rise buildings, both in China and abroad, have demonstrated new innovations from the creative concept to the creative method. from the creative concept to the creative method. At the same time, digital technology has enabled more design freedom in the vertical dimension. "Twisting" has gradually become the morphological choice of many city landmark buildings in recent years. The form seems more likely to be driven by the interaction of aesthetics and structural engineering. Environmental performance is often a secondary consideration; it is typically not simulated until the evaluation phase. Based on the research results of "DigitalFUTURE Shanghai 2017 Workshop - Wind Tunnel Visualization", an approach that can be employed by architects to design environmental-performance buildings during the early stages has been explored. The integration of a dynamic form-finding approach (DFFA) and programming transforms the complex relationship between architecture and environment into a dialogue of computer language and dynamic models. It allows the design to focus on the relationship between morphology and the surrounding environment, and is not limited to the envelope form itself. This new concept of DFFA in this research consists of three elements: 1) architectural form; 2) integration of wind tunnel and dynamic models; and 3) environmental response. The concept of wind tunnel testing integrated with a dynamic model fundamentally abandons the functional definition of the traditional static environment simulation analysis. Instead it is driven by integral environmental performance as the basic starting point of morphological generation.

Ni Nanoparticle Anchored on MWCNT as a Novel Electrochemical Sensor for Detection of Phenol

  • Wang, Yajing;Wang, Jiankang;Yao, Zhongping;Liu, Chenyu;Xie, Taiping;Deng, Qihuang;Jiang, Zhaohua
    • Nano
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    • v.13 no.11
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    • pp.1850134.1-1850134.10
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    • 2018
  • Increasing active sites and enhancing electric conductivity are critical factors to improve sensing performance toward phenol. Herein, Ni nanoparticle was successfully anchored on acidified multiwalled carbon nanotube (a-MWCNT) surface by electroless plating technique to avoid Ni nanoparticle agglomeration and guarantee high conductivity. The crystal structure, phase composition and surface morphology were characterized by XRD, SEM and TEM measurement. The as-prepared Ni/a-MWCNT nanohybrid was immobilized onto glassy carbon electrode (GCE) surface for constructing phenol sensor. The phenol sensing performance indicated that Ni/a-MWCNT/GCE exhibited an amazing detection performance with rapid response time of 4 s, a relatively wide detection range from 0.01 mM to 0.48 mM, a detection limit of $7.07{\mu}M$ and high sensitivity of $566.2{\mu}A\;mM^{-1}\;cm^{-2}$. The superior selectivity, reproducibility, stability and applicability in real sample of Ni/a-MWCNT/GCE endowed it with potential application in discharged wastewater.