• Title/Summary/Keyword: Urban morphology

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Human Impacts on Urban Landscapes in North American Desert: A Case Study in the Phoenix, Arizona, USA (북아메리카 사막 지형에 미친 인류의 영향: 피닉스, 애리조나 지역을 사례로)

  • Jeong, Ara
    • Journal of The Geomorphological Association of Korea
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    • v.26 no.3
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    • pp.69-85
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    • 2019
  • Humans have been important driver to reconfigure the terrestrial surface of the Earth by altering its morphology and processes. The effect of human activities on the physical landscape, however, shows substantially uneven geographical patterns. Most of anthrogemorphoogical studies regarding human-induced denudation have focused on areas with a long history of human modifications such as humid landscapes, so the hypothesis is naturally a great human impact on landscapes. The effect of human activities on dryland Earth surfaces are far less commonly studied, although erosion is one of major concerns in arid and semi-arid region regarding land and water quality degradation. The urban metropolis of Phoenix, Arizona, USA provides an opportunity to explore the impact of the Anthropocene. The Phoenix metropolitan area rests on classic desert landforms, such as extensive pediments, alluvial fans and sand sheets. Human activities including cattle crazing, wildfire resulting from introduced grass species by human, and recent urbanization processes have impacted these classic desert landforms and altered geomorphic processes. The purpose of this paper, therefore, rests in examining Anthropocene in the geomorphology of the north-central Sonoran Desert. The objectives of this paper are: i) to understand the impact of the Anthropocene on the geomorphological processes and forms through field observations; ii) to quantify the magnitude of human impacts on landscape using a published two-decade long record of erosion dataset and natural background erosion dataset in submitted manuscript at the sprawling edge of the Phoenix metropolitan region; iii) to examine how geomorphic outcome can affect the sustainability of cities through the estimation of sediment yield under the condition of urban sprawl.

A Study on Spatial Structure Characteristics of Earthen Walled Fortresses (토성(土城)의 공간구조 특성 연구)

  • Lee, Sang-Seok;Jang, Mi-Ran
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.32 no.1
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    • pp.74-82
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    • 2014
  • The purposes of this study is to investigate spatial structure characteristics of earthen walled fortresses based on topography, which are locational and Plane morphology, Cross sections of earthworks. Target areas of this study are 37 earthen walled fortresses which are designated as cultural properties. This study is conducted with methodologies of literature review, field investigation, investigation on topography materials and relation analyses of topography&spatial structure. The results from study on spatial structure of earthen walled fortresses are as follows. First, Earthen walled fortresses on flat topography were adjacent to water systems like rivers or streams. Plane morphology showed regular shapes. The cross section morphology presented trapezoid the most with earthworks of which outer and inner walls were built. Second, More than 70% of earthen walled fortresses on hilly topography had water system within close range of approximately 1.5km. Plane morphology was mainly with more than 73% of irregular types. Cross sections of earthworks were of morphology with more than 86% of bordered type and another type leaning against existing topography like mountains. Third, 59% of earthen walled fortresses in mountain areas had water system within their close range, which indicated that they depended on external water system less than those with hilly topography. Plane morphology was mainly with more than 67% of irregular types. Cross sections of earthworks were of monoslope method with more than 94% of bordered type and another type leaning against mountains.

Morphological Interpretation of the Transformation Process of Urban Form in Gosan-Up (형태학적 개념을 활용한 조선시대 고산현의 도시형태 변천과정 해석)

  • Lee, Kyung-Chan;Kang, In-Ae
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.32 no.4
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    • pp.37-49
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    • 2014
  • This paper aims to interpret the transformation process of town plan of Gosan-up(高山), which was provincial administrative focus town in Josun dynasty, basing on morphological viewpoint. Morphological concepts, such as morphological frame, urban plan, kernel, colonization, route system, fixation line, fringe belt, plan unit & plan division, morphological period derived from the study of Conzen, M.R.G. and Caniggia, G. epidome district, break point, broken plot, urban fallow, privatization are adopted for the interpretation of urban form. Morphological period of Gosan can be divided in four ; formation of kernel & morphological structure, disintegration & redevelopment of the kernel, augmentative development of the kernel & formation of modern epidome district, outwards expanding of urbanized area, transition & reorganization of epidome district. Especially public leading projects such as construction of new regional connection road and public facilities such as myeon(township) office, agricultural cooperatives federation office, market, are main factors of morphological transformation of townplan. In the early stage, under the Japanese imperialism, construction of the new matrix route(Gosan-ro) through the kernel and followed planned routes gave way to disintegrating traditional areal plan unit and forming small block plan units in administrative facilities area. And linear plan units with commercial buildings were formed along the new matrix route and planned route adjacent to periodical market. In the latter stage, with development of public facilities, private sectors' large circulation institution and terminal outside the kernel with planned routes formed areal block based plan units with commercial and public buildings. And part of the spatial area with the linear plan unit were turned into urban fallow. With the transformation of town plan, new roads outside the kernel have substituted for traditional fixation line of waterway with road and topographical feature. Fringe belts were made successively along the new road and around the major intersections outside of existing urbanized area. Land use in fringe belts, constituting of outer locational tendency early on formation, was gradually replaced with commercial & business buildings.

Synthesis of High-Aspect-Ratio BaTiO3 Platelets by Topochemical Conversion and Fabrication of Textured Pb(Mg1/3Nb2/3)O3-32.5PbTiO3 Ceramics

  • Zhao, Wei;E, Lei;Ya, Jing;Liu, Zhifeng;Zhou, Heping
    • Bulletin of the Korean Chemical Society
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    • v.33 no.7
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    • pp.2305-2308
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    • 2012
  • Perovskite structured barium titanate particles ($BaTiO_3$) platelets were synthesized by molten salt synthesis and topochemical microcrystal conversion. As the precursors of $BaTiO_3$, plate-like $BaBi_4Ti_4O_{15}$ particles were first synthesized by the reaction of $Bi_4Ti_3O_{12}$, $BaCO_3$, and $TiO_2$ at $1080^{\circ}C$ for 3 h in $BaCl_2$-KCl molten salt. After the topochemical reactions, layer-structured $BaBi_4Ti_4O_{15}$ particles transformed to the perovskite $BaTiO_3$ platelets. $BaTiO_3$ particles with thickness of approximately $0.5{\mu}m$ and a length of $10-15{\mu}m$ retained the morphology feature of the $BaBi_4Ti_4O_{15}$ precursor. For <001> $Pb(Mg_{1/3}Nb_{2/3})O_3-32.5PbTiO_3$ (PMNT)-5 wt % PbO piezoelectric ceramics textured with 5 vol % of $BaTiO_3$ templates, the Lotgering factor reached 0.82, and $d_{33}$ was 870 pC/N.

Diurnal and Nocturnal Behaviour of Airborne Cryptomeria japonica Pollen Grains and the Allergenic Species in Urban Atmosphere of Saitama, Japan

  • Wang, Qingyue;Nakamura, Shinichi;Lu, Senlin;Nakajima, Daisuke;Suzuki, Miho;Sekiguchi, Kazuhiko;Miwa, Makoto
    • Asian Journal of Atmospheric Environment
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    • v.7 no.2
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    • pp.65-71
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    • 2013
  • Japanese cedar (Cryptomeria japonica) pollinosis is the most popular pollinosis in Japan. It has been reported that Cryptomeria japonica pollen allergenic species are suspended as fine particles in the urban atmosphere. These allergenic fine particles are responsible for inducing asthma by breaking into the lower respiratory tract. It has also been found that pollinosis symptoms on the sufferers appear mainly at night-time by the results from epidemiological studies. However, the exact reason for these phenomena is not yet clarified. In this study, the diurnal and nocturnal behaviours of Cryptomeria japonica pollen grains and their allergenic species in the urban area of Saitama city of Kanto Plain were investigated. Airborne pollen grains and allergenic Cry j 1 concentrations in total suspended particulate matter (TSP) were investigated at two sampling sites, a heavy traffic road (roadside site) and at the balcony of the $10^{th}$ floor of the Building of Research and Project of Saitama University (general urban site). The latter sampling site where located about 300 m away from the roadside site was used as a general urban site unaffected by automobile traffic. The airborne pollen counts were measured with a real-time pollen monitor. Cry j 1 particles were collected with two high volume air samplers, and these concentrations were measured by surface plasmon resonance method with a Biacore J system. The diurnal variation of the airborne pollen counts was similar to the trends of temperature and wind speed during the day-time; whereas its tendency with wind speed trend was not observed during the night-time. Airborne pollen counts were lower with northern wind than with southern wind because the pollen comes from the mountainous areas, and the mountains in the south are closer, about half the distance to the northern mountains. It is suggested that the peaks of airborne pollen counts during night-time in the sampling site occurred by transport of pollen grains released during day-time in the mountainous forest areas, located c.a. 100 km away from the sampling site. On the roadside site the allergenic Cry j 1 concentrations were higher than at the general urban site, nevertheless pollen grains counts were lower. These results suggested that worsening of pollinosis symptoms during night-time in urban area was caused by transport of pollen grains during day-time in the mountainous forest areas. Moreover, pollen allergenic species become different morphology from pollen grain at roadside site, and the subsequent pollen grains re-suspension by automobile traffic.

Ultrafine Particle Events in the Ambient Atmosphere in Korea

  • Maskey, Shila;Kim, Jae-Seok;Cho, Hee-Joo;Park, Kihong
    • Asian Journal of Atmospheric Environment
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    • v.6 no.4
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    • pp.288-303
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    • 2012
  • In this study, real time measurements of particle number size distribution in urban Gwangju, coastal Taean, and industrial Yeosu in Korea were conducted in 2008 to understand the occurrence of ultrafine particle (UFP) (<100 nm) events, the variation of its concentration among different sampling sites, and UFP formation pathways. Also, to investigate seasonal and long-term variation of the UFP number concentration, data were collected for the period of 5 years (2007, 2008, 2010, 2011, and 2012) in urban Gwangju. Photochemical and combustion events were found to be responsible for the formation of UFP in the urban Gwangju site, whereas only photochemical event led to the formation of UFP in the coastal Taean site. The highest UFP concentration was found in industrial Yeosu (the average UFP number fractions were 79, 59 and 58% in Yeosu, Gwangju, and Taean, respectively), suggesting that high amount of gas pollutants (e.g., $NO_2$, $SO_2$, and volatile organic carbon (VOC)) emitted from industries and their photochemical reaction contributed for the elevated UFP concentration in the industrial Yeosu site. The UFP fraction also showed a seasonal variation with the peak value in spring (61.5, 54.5, 50.5, and 40.7% in spring, fall, summer, and winter, respectively) at urban Gwangju. Annual average UFP number concentrations in urban Gwangju were $5.53{\times}10^3\;cm^{-3}$, $4.68{\times}10^3\;cm^{-3}$, $5.32{\times}10^3\;cm^{-3}$, $3.99{\times}10^3\;cm^{-3}$, and $2.16{\times}10^3\;cm^{-3}$ in the year 2007, 2008, 2010, 2011, and 2012, respectively. Comparison of the annual average UFP number concentration with urban sites in other countries showed that the UFP concentrations of the Korean sites were lower than those in other urban cities, probably due to lower source strength in the current site. TEM/EDS analysis for the size-selected UFPs showed that the UFPs were classified into various types having different chemical species. Carbonaceous particles were observed in both combustion (soot and organics) and photochemical events (sulfate and organics). In the photochemical event, an internal mixture of organic species and ammonium sulfate/bisulfate was identified. Also, internal mixtures of aged Na-rich and organic species, aged Ca-rich particles, and doughnut shaped K-containing particles with elemental composition of a strong C with minor O, S, and K-likely to be originated from biomass burning nearby agricultural area, were observed. In addition, fly ash particles were also observed in the combustion event, not in the photochemical event.

A Study on the Roughness Length Spatial Distribution in Relation to the Seoul Building Morphology (서울시 건물형태에 따른 거칠기길이 분포특성 연구)

  • Yi, Chaeyeon;Kwon, Tae Heon;Park, Moon-Soo;Choi, Young Jean;An, Seung Man
    • Atmosphere
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    • v.25 no.2
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    • pp.339-351
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    • 2015
  • The purpose of this study is for the fundamental understandings about building morphological parameters and aerodynamic roughness parameters of Seoul, Korea using the detailed urban geographic information datasets. Applied roughness parameter calculations are based on a digital map of buildings with lot area polygons. The quality of the developed roughness length ($z_0$) of Seoul was evaluated with densely installed 107 automatic weather stations. The correlation coefficient results between averaged wind speeds of AWS data and averaged $z_0$ is -0.303 in night and -0.398 in day (200 m radii circles case). Further $z_0$ enhancement should follow by considering other surface features such as high tree and orography of Seoul. However, this study would meet the needs to for local- or meso-scale meteorological modeling applications of Seoul. However, further studies would require for enhancing the $z_0$ applications of Seoul.

Analysis of River Channel Morphology and Riparian Land Use Changes Using Aerial Photographs and GIS (항공사진과 GIS를 이용한 하천형태 및 하천부지 변화추세 분석)

  • Park, Geun-Ae;Lee, Mi-Seon;Kim, Hyeon-Jun;Kim, Seong-Joon
    • Journal of The Korean Society of Agricultural Engineers
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    • v.47 no.2
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    • pp.15-21
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    • 2005
  • 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. Apparent changes of the stream were found that the consolidated reaches of stream by levee construction became straight together with widening of their stream widths. Especially the stream width of inlet part of Paldang lake widened almost twice because of the rise of water level by dam construction in 1974. The land use of riparian areas of three selected years were classified into six categories (water, forest, agricultural land, urban area, road, sandbar) by digitizing method. The forest and agricultural lands decreased and urban area increased as the stream maintenance had been performed.

A Historical Study of the Railroad Construction by the Empire of Japan and the change of Eupchi in Modern Korea (근대 한국에 있어 일본제국에 의한 철도건설과 읍치의 변화에 관한 역사적 연구)

  • Kim, Hun-Gyu
    • Journal of architectural history
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    • v.17 no.6
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    • pp.29-44
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    • 2008
  • This paper analyses the railroad trunk line constructed in the Korea since the end of the 19th century. The analysis consists of the following problematics. 1) The process of the decision of the railroad route 2) The relationship of the location of Eupchi and the stations By clarifying the above, the purpose of this paper is to clarify how the morphology of the city in Korea has been affected by the change in the relationship with Korea and Japan. The Empire of Japan has been reconnoitering the Korea since way before the formal contract for the railroad construction was signed. Therefore, the Empire of Japan had a very good understanding of the actual transportation system when it started the construction of the railroad. The railroad construction was used by the Empire of Japan to empower the control over the Korea. For this reason, the new railroad system was constructed as a different system from the former transportation system and the urban system was also affected. Also the relationship of the western powers and Japan around the turn of the 20th century defined the characteristic of the railway system as a pathway through the Korean peninsular to link Japan to the continent. Moreover, being apprehensive about the friction with the western, Japan located the railway stations to avoid the missionary land properties. This made it clear that the restraint relationship between Japan and the western affected the urban special structure.

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Analysis of Urban Heat Island Effect Using Information from 3-Dimensional City Model (3DCM) (3차원 도시공간정보를 이용한 도시열섬현상의 분석)

  • Chun, Bun-Seok;Kim, Hag-Yeol
    • Spatial Information Research
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    • v.18 no.4
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    • pp.1-11
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    • 2010
  • Unlike the previous studies which have focused on 2-dimensional urban characteristics, this paper presents statistical models explaining urban heat island(UHI) effect by 3-dimensional urban morphologic information and addresses its policy implications. 3~dimensional informations of Columbus, Ohio arc captured from LiDAR data and building boundary informations are extracted from a building digital map, Finally NDV[ and temperature data are calculated by manipulating band 3, band 4, and thermal hand of LandSat images. Through complicated data processing, 6 independent variables(building surface area, building volume, height to width ratio, porosity, plan surface area) are introduced in simple and multiple linear regression models. The regression models are specified by Box-Tidwell method, finding the power to which the independent variable needs to raised to be in a linearity. Porosity, NDVI, and building surface area are carefully chosen as explanatory variables in the final multiple regression model, which explaining about 57% of the variability in temperatures. On reducing UHI, various implications of the results give guidelines to policy-making in open space, roof garden, and vertical garden management.