• Title/Summary/Keyword: TOPOGRAPHIC STRUCTURE

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Three-Dimensional Numerical Experiment on the Tide-Induced Residual Currents around a Circular Island (원형섬 주변 조사 잔차류에 대한 삼차원 수치실험연구)

  • 이호진;최현용;정종률
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.5 no.4
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    • pp.338-349
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    • 1993
  • Most of numerical models for studying tide-induced residual currents (TIRC) were to dimensional depth averaged models which were confined to anlayze the horizontal structure of TIRC. In this study, TIRC occurring around a circular island was simulated with the three-dimensional spectral model which employed by the finite difference method in the horizontal direction and the expansion of basis function in the vertical direction. The main results of numerical experiment can be summarized as follows. Firstly. both topographic and nonlinear effect played an important role in the generation of TIRC. Secondly, when the currents were rotary clockwise. the horizontal structure of TIRC appeared to rotate in the same direction. These results were consistent with those of previous studies of two-dimensional numerical models.

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Land Suitability Analysis using GIS and Satellite Imagery

  • Yoo, Hwan-Hee;Kim, Seong-Sam;Ochirbae, Sukhee;Cho, Eun-Rae;Park, Hong-Gi
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.25 no.6_1
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    • pp.499-505
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    • 2007
  • A method of improving the correctness and confidence in land use classification as well as urban spatial structure analysis of local governments using GIS and satellite imagery is suggested. This study also compares and analyzes LSAS (Land Suitability Assessment System) results using two approaches-LSAS with priority classification, and LSAS using standard estimation factors without priority classification. The conclusions that can be drawn from this study are as follows. First, a method of maintaining up-to-date local government data by updating the LSAS database using high-resolution satellite imagery is suggested. Second, to formulate a scientific and reasonable land use plan from the viewpoint of territory development and urban management, a method of simultaneously processing the two described approaches is suggested. Finally, LSAS was constructed by using varieties of land information such as the cadastral map, the digital topographic map, varieties of thematic maps, and official land price data, and expects to utilize urban management plan establishment widely and effectively through regular data updating and problem resolution of data accuracy.

A Study on the Characteristics of the Heavy Rainfall Events in Honam District along the Border of mT Airmass

  • Yang, Se-Hwan;Ryu, Chan-Su
    • Journal of Integrative Natural Science
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    • v.5 no.4
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    • pp.220-228
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    • 2012
  • District of Korea affected by westerly wind and heavy rainfall is predominantly distributed in the west and south of Honam district. So, this study is becoming a necessity. In this study, it is investigated that the characteristics of heavy rainfall occurred frequently in Honam district along the border of mT airmass after the end of rainy season due to atmospheric instability, lower (850 hPa) convergence and topographic effect. Our results show that heavy rainfall occurred in Honam district along the border of mT airmass results from the appropriate mechanism of the unstable vertical structure and moisture flux in the expansion and contraction of the border of mT airmass. All things considered, the improvement of the predictability of heavy rainfall occurred in Honam district along the border of mT airmass could be possible by the generalization of the results of this study.

A Study for Open Space System Establishment of Chonju City -Chiefly as Viewed the Concept of Specified Nodes & Corridors- (전주시 "오픈스페이스"체계 수립에 관한 연구: 특화된 결정점과 "코리도"개념의 도입을 중심으로-)

  • 최만봉;김재식
    • Journal of the Korean Institute of Landscape Architecture
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    • v.15 no.1
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    • pp.69-84
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    • 1987
  • According to the complexity and the pluralism of the modern cities, they are changing themselves into the multinoded and social - classless urban environments. The sudden drift of population to the cities is giving rise to the serious environmental problems, and the rapid increase of recreational needs among the citizen is changing the urban society into a leisure - oriented one. In order to coping with the abrupt change in the social and natural urban environments, the various fields of urban society should be co - ordinated. The study uses the green - city concept to get solves the incongruity of urban structure in Chonju City. The existing open space maps were drawn up by the various techniques such as the analysis of the topographic maps and collected data, the interpretation of the aero-photographs and the reconnaissance of site. The authors suggested the existing condition, and the problems and potentials of open space elements in Chonju City through the analysis of the existing condition maps. After synthesizing the contents of analysis, the 7u(hors established an exclusive open space system for Chonju City.

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A Study on the Grid Land Subdivision of Ancient Local City in Korea (고대 한국 지방도시 격자형 토지구획의 형태특성에 관한 연구)

  • Lee, Kyung-Chan
    • Journal of architectural history
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    • v.11 no.4 s.32
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    • pp.45-69
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    • 2002
  • This study aims to find out the genetic characteristics of gridded subdivision area which has its origin from ancient local administrative city-Sangju, Jeonju, Namwon, Kwangju, Chungju. The spatial structure, based on the inter-relationship among gridded subdivision area, city wall, and topographic condition, and the morphological characteristics of gridded subdivision area are analyzed. The points of analysis on morphological characteristics of gridded subdivision area consist of the size of unit block, the organization system of unit block, the orientation of subdivision line. As a result of the analysis, three main characteristics are found. Firstly there can be found no same land subdivision rule among study areas. Secondly, the morphological features of study area were the products of cumulative process of different subdivision areas which were developed in different periods. Thirdly, the original regular gridded land subdivision seems to have been carried out in the object of a farm-land cultivation around 7th century. And there was a change of land-use from farm land to urban land-use during the later 7th century and 8th century.

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Digital Elevation Map Generation using SAR Stereo Technique with Radarsat Images over Seoul Area

  • Ka, Min-Ho;Kim, Man-Jo
    • Korean Journal of Remote Sensing
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    • v.17 no.2
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    • pp.155-164
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    • 2001
  • In this study, we describe the technique for deriving a digital elevation model (DEM) from a synthetic aperture radar (SAR) stereo image pair and apply it to an image pair over "Kwanak-san" in Seoul, Korea. This paper contains brief discussion of the use of stereo SAR to derive topographic data, description of the overall structure of the stereo SAR processing system, description of the site and SAR data used for the evaluation and the source of validation data, results of the stereo SAR processing, analysis and evaluation of their accuracy against map data, and finally summarizes the main highlights of the method used, comments and recommendations on its future implementation.

Interpretation on the subsurface velocity structure by seismic refraction survey in tunnel and slope (탄성파 굴절법 탐사를 이용한 지반 속도분포 해석-터널 및 절토 사면에의 적용 사례)

  • You Youngjune;Cho Chang Soo;Park Yong Soo;Yoo In Kol
    • 한국지구물리탐사학회:학술대회논문집
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    • 1999.08a
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    • pp.48-64
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    • 1999
  • For quantitative evaluation of geotechnical engineering properties such as rippability and diggability, clear interpretation on the subsurface velocity structures should be preceded by figuring out top soil, weathered and soft rock layers, shape of basement, fracture zones, geologic boundary and etc. from the seismic refraction data. It is very important to set up suitable field parameters, which are the configuration of profile and its length, spacings of geophones and sources and topographic conditions, for increasing field data quality Geophone spacing of 3 to 5m is recommended in the land slope area for house land development and 5 to 10m in the tunnel site. In refraction tomography technique, the number of source points should be more than a half of available channel number of instrument, which can make topographic effect ignorable. Compared with core logging data, it is shown that the velocity range of the soil is less than 700m/s, weathered rock 700${\~}$1,200m/s, soft rock 1,200${\~}$1,800m/s. And the upper limit of P-wave velocity for rippability is estimated 1,200 to 1,800m/s in land slope area of gneiss. In case of tunnel site, it is recommended in tunnel design and construction to consider that tunnel is in contact with soft rock layer where three lineaments intersecting each other are recognized from the results of the other survey.

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A Case Study on Seismic Refraction Tomography Survey for Subsurface Structure Interpretation (지하구조 해석을 위한 탄성파 굴절법 토모그라피 탐사 사례연구)

  • 유영준;유인걸;송무영
    • The Journal of Engineering Geology
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    • v.11 no.2
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    • pp.163-174
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    • 2001
  • For quantitative evaluation of geotechnical engineering properties such as rippability and diggability, clear interpretation on the subsUJiace velocity structures should be preceded by figuring out top soil, weathered and soft rock layers, shape of basement, fracture zones, geologic boundary and etC. from the seismic refraction data. It is very important to set up suitable field parameters, which are the configuration of profile and its length, spacings of geophones and sources and topographic conditions, for increasing field data Quality. Geophone spacing of 3 to 5m is reconunended in the land slope area of house land development site. In refraction tomography technique, the number of source points should be more than a Cluarter of available channel number of instrument and the subsurface structure interpretation can be decreased the artifact of inversion by topographic effect. Compared with core logging data, it is shown that the velocity range of the soil is less than 700m/s, weathered rock 700~1,200m/s, soft rock 1,200~1,800m/s on the velocity tomogram section. And the upper limit of P-wave velocity for rippability is estimated 1,200 to 1,800m/s in land slope area of gneiss.

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Characteristic study of mechanical properties of Structural rolled steel and Stainless steel for MIG welding (구조용 압연강재와 스테인리스 강재의 MIG 용접에 대한 기계적 특성연구)

  • Lim, J.Y.;Yoon, M.J.;Kim, S.Y.;Kim, T.G.
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.13 no.1
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    • pp.100-106
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    • 2014
  • It is well known that fatigue failures occur on welded structures in industrial application due to repetitive load force. In order to decrease the incidence of fatigue failure, we analyzed the mechanical properties based on structural aspects in rolled steel(SS 400) welded onto stainless steel (STS 304) by the MIG welding method as well as the structure of rolled steel welded onto itself. We compared the hardness, tensile and fatigue properties with two types of samples which had no defects on the welding parts as observed by X-ray topographic analysis. It was found that the tensile and fatigue strength levels of SS 400 welded onto STS 304 by the MIG welding method were higher than those of STS 304 welded onto itself.

Water Mass Distribution and Currents in the Vicinity of the Hupo Bank in Summer 2010 (2010년 하계 후포퇴 근해의 수괴분포와 해류)

  • Lee, Jae Chul
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.49 no.1
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    • pp.61-73
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    • 2016
  • Water mass distribution and currents were investigated off the east coast of Korea near the Hupo Bank using the CTD and ADCP data from June to August 2010. The typical water masses were: (1) Tsushima Surface Water (TSW) from the East Korean Warm Current (EKWC) in the surface layer, (2) a shallow thermocline at 20-30 m depth, (3) Tsushima Middle Water (TMW) of high salinity (>34.2) below the pycnocline, (4) North Korean Cold Water (NKCW) of low salinity (<34.05) and low temperature (<4°C) in the lower layer. In June, a double eddy was observed in which a cold filament intruded cyclonically from the south around a pre-existing cold-core eddy. A burst of strong southward current was recorded in mid-August due to a warm filament from the meandering EKWC. Current in the N-S direction was predominant due to topographic effects, and the direction of the northward EKWC was frequently reversed in its direction due to the eddy-filament activity, whereas the influence of the wind was not noticeable. The vertical structure of the current was of a two-layer system, with the northward EKWC in the upper layer and weak southward flows corresponding to the North Korean Cold Current (NKCC) in the deeper layer.