• Title/Summary/Keyword: Topographic Characteristics

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Study on the Terrestrial LiDAR Topographic Data Construction for Mountainous Disaster Hazard Analysis (산지재해 위험성 분석을 위한 지상 LiDAR 지형자료 구축에 관한 연구)

  • Jun, Kye Won;Oh, Chae Yeon
    • Journal of the Korean Society of Safety
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    • v.31 no.1
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    • pp.105-110
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    • 2016
  • Mountainous disasters such as landslides and debris flow are difficult to forecast. Debris flow in particular often flows along the valley until it reaches the road or residential area, causing casualties and huge damages. In this study, the researchers selected Seoraksan National Park area located at Inje County (Inje-gun), Gangwon Province-where many mountainous disasters occur due to localized torrential downpours-for the damage reduction and cause analysis of the area experiencing frequent mountainous disasters every year. Then, the researchers conducted the field study and constructed geospatial information data by GIS method to analyze the characteristics of the disaster-occurring area. Also, to extract more precise geographic parameters, the researchers scanned debris flow triggering area through terrestrial LiDAR and constructed 3D geographical data. LiDAR geographical data was then compared with the existing numerical map to evaluate its precision and made the comparative analysis with the geographic data before and after the disaster occurrence. In the future, it will be utilized as basic data for risk analysis of mountainous disaster or disaster reduction measures through a fine-grid topographical map.

A Study on the Rural Village Planning in North Korea (북한의 농촌마을 계획에 관한 연구)

  • Kim, Shin-Won;Heo, Jun
    • Journal of Korean Society of Rural Planning
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    • v.6 no.2 s.12
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    • pp.59-72
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    • 2000
  • This study examines the rural village planning in North Korea after the Liberation of Korea in 1945. For conducting this study, the creation of rural villages in North Korea were investigated according to the following periods: from the Liberation of Korea to the outbreak of the Korean War, from the end of the Korean War to the 1950's, 1960's, 1970's and 1980's. In this study, major rural villages were also examined and common characteristics of rural village-making in North Korea were analyzed. The following are the findings from this study. In rural village planning, historic revolutionary sites and buildings, where revolutionary achievements of Kim, Ill-Sung and Kim, Jung-Ill were reached, are well preserved and actively created. (2) Rural villages are intended to be a place for ideological education, productive activities and cultural refreshment. (2) In rural village-making, inclined planes are utilized, in consideration of climatic and topographic conditions. (4) The construction of residential areas with modern private houses is considered to be important in the making of socialistic and communist rural communities in North Korea. (5) For economic reasons, existing villages, buildings and facilities are preserved and local building materials are broadly used.

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Management Scheme of Urbanization Runoff Using XP-SWMM (XP-SWMM을 이용한 도시화 유역에서의 유출 관리 방안 연구)

  • Lee, Beum-hee;Chai, Jun-young
    • Proceedings of the Korea Water Resources Association Conference
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    • 2004.05b
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    • pp.1167-1172
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    • 2004
  • Recently, runoff characteristics of urban area are changing because of the increase of impervious area by rapid increasing of population and industrialization, urbanization. It needs to extract the accurate topological and hydrological parameters of watersheds in order to manage water resource efficiently. In this paper, rainfall-runoff analysis in An-Yang stream basin was made using GIS(Geographic Information System) and XP-SWMM(Export Stormwater and Wastewater Management Model). The basin was divided into 13 sub-basins using GIS. The area, slope, width of each subcatchment and length, slop of each stream reach were acquired from topographic maps, and imperviousness rate, land use types, infiltration capacities of each subcatchment from land use maps and soil maps using GIS. We gave th runoff management method of urbanization area us ing XP-SWMM.

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Region-Scaled Soil Erosion Assessment using USLE and WEPP in Korea

  • Kim, Min-Kyeong;Jung, Kang-Ho;Yun, Sun-Gang;Kim, Chul-Soo
    • Korean Journal of Environmental Agriculture
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    • v.27 no.4
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    • pp.314-320
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    • 2008
  • During the summer season, more than half of the annual precipitation in Korea occurs during the summer season due to the geographical location in the Asian monsoon belt. So, this causes severe soil erosion from croplands, which is directly linked to the deterioration of crop/land productivity and surface water quality. Therefore, much attention has been given to develop accurate estimation tools of soil erosion. The aim of this study is to assess the performance of using the empirical Universal Soil Loss Equation (USLE) and the physical-based model of the Water Erosion Prediction Project (WEPP) to quantify eroded amount of soil from agricultural fields. Input data files, including climate, soil, slope, and cropping management, were modified to fit into Korean conditions. Chuncheon (forest) and Jeonju (level-plain) were selected as two Korean cities with different topographic characteristics for model analysis. The results of this current study indicated that better soil erosion prediction can be achieved using the WEPP model since it has better power to illustrate a higher degree of spatial variability than USLE in topography, precipitation, soils, and crop management practices. These present findings are expected to contribute to the development of the environmental assessment program as well as the conservation of the agricultural environment in Korea.

Computation of Complete Bouguer Anomalies in East Sea (동해 지역의 완전부우게 이상 계산)

  • Kim, Young-Hyun;Yun, Hong-Sik;Lee, Dong-Ha;Huang, He
    • Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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    • 2010.04a
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    • pp.165-168
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    • 2010
  • This paper describes the results of complete Bouguer anomalies computed from the Free-air anomalies that derived from Sandwell and DNSC08 mairne gravity models. Complete bouguer corrections consist of three parts: the bouguer correction (Bullard A), the curvature correction (Bullard B) and the terrain correction (Bullard C). These all corrections have been computed over the East Sea on a $1'{\times}1'$ elevation data (topography and bathymetry) derived from ETOPO1 global relief model. In addition, a constant topographic (sea-water) density of $2,670kg/m^3$ ($1,030kg/m^3$) has been used for all correction terms. The distribution of complete bouguer anomalies computed from DNSC08 are -34.390 ~ 267.925 mGal, and those from Sandwell are -32.446 ~ 266.967 mGal in East Sea. The mean and RMSE value of the difference between DNSC08 and Sandwell is $0.036{\pm}2.373$ mGal. The highest value of complete bouguer anomaly are found around the region of $42{\sim}43^{\circ}N$ and $137{\sim}139^{\circ}E$ (has the lowest bathymetry) in both models. Theses values show that the gravity distribution of both models, DNSC08 and Sandwell, are very similar. They indicate that satellite-based marine gravity model can be effectively used to analyze the geophysical, geological and geodetic characteristics in East Sea.

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Flood Simulation of Upriver District Considering an Influence of Backwater

  • Um, Dae Yong;Song, Yong Hyun
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.30 no.6_2
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    • pp.631-642
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    • 2012
  • This study aims to predict inundation and flood-stricken areas more accurately by simulating flood damage caused by reversible flow of rain water in the upper water system through precise 3D terrain model and backwater output. For the upstream of the South Han-River, precise 3D terrain model was established by using aerial LiDAR data and backwater by area was output by applying the storm events of 2002 including the history of flood damage. The 3D flood simulation was also performed by using GIS Tool and for occurrence of related rainfall events, inundation events of the upriver region of water system was analyzed. In addition, the results of flood simulation using backwater were verified by making the inundation damage map for the relevant area and comparing it with flood simulation's results. When comparing with the results of the flood simulation applying uniformly the gauging station's water surface elevation used for the existing flood simulation, it is found that the results of the flood simulation using backwater are close to the actual inundation damage status. Accordingly, the causes of flood occurred in downstream of water system and upstream that has different topographic characteristics could be investigated and applying the simulation with backwater is proved more proper in order to procure accuracy of the flood simulation for the upriver region.

A Comparative Analysis between Rigorous and Approximate Approaches for LiDAR System Calibration

  • Kersting, Ana Paula;Habib, Ayman
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.30 no.6_2
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    • pp.593-605
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    • 2012
  • LiDAR systems provide dense and accurate topographic information. A pre-requisite to achieving the potential accuracy of LiDAR is having a proper system calibration, which aims at estimating all the systematic errors in the system measurements and the mounting parameters relating the different components. This paper presents a rigorous and two approximate methods for LiDAR system calibration. The rigorous approach makes use of the LiDAR equation and the system raw measurements. The approximate approaches utilize simplified LiDAR equations using some assumptions, which allow for less strict requirements regarding the raw measurements. The first presented approximate method, denoted as quasi-rigorous, assumes that we are dealing with a vertical platform (i.e., small pitch and roll angles). This method requires time-tagged point cloud and trajectory position data. The second approximate method, denoted as simplified, assumes that we are dealing with parallel strips, vertical platform, and minor terrain elevation variations compared to the flying height above ground. Such method can be performed using the LiDAR point cloud only. Experimental results using a real dataset, whose characteristics deviate to some extent from the utilized assumptions in the approximate methods, are presented to provide a comparative analysis of the outcome from the introduced methods.

Characterizing Pb-based superconducting thin films

  • Park, Sang-Il;Kim, Hong-Seok;Lee, Joon Sung;Doh, Yong-Joo
    • Progress in Superconductivity and Cryogenics
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    • v.16 no.4
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    • pp.36-39
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    • 2014
  • We report on the superconducting and structural characteristics of Pb-based alloy ($Pb_{0.9}In_{0.1}$, $Pb_{0.8}In_{0.2}$ and $Pb_{0.85}Bi_{0.15}$) thin films, depending on the film deposition rate. The maximum critical magnetic field strength of $Pb_{0.85}Bi_{0.15}$ is almost six times larger than that of $Pb_{0.9}In_{0.1}$, and more rapid growth of the film enhances the critical magnetic field strength even for the same alloy material. Scanning electron microscopy inspection indicates that lower deposition rate condition is vulnerable to the formation of void structure in the film. Topographic images using atomic force microscopy are useful to optimize the deposition condition for the growth of smooth superconducting film. Our work can be utilized for future studies on hybrid superconducting devices using low-dimensional nanostructures.

A Study on Flash Flood Warning Trigger Rainfall in Mountainous Area (산악지역 돌발홍수 기준우량 결정에 관한 연구)

  • Jun, Kye-Won;Oh, Chae-Yeon
    • Journal of the Korean Society of Safety
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    • v.24 no.1
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    • pp.89-94
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    • 2009
  • The purpose of this study is to estimate the critical flood discharge and flash flood trigger rainfall for alarm system providing for a flash flood in mountainous area. The flash flood need non-linear approaching method, because rainfall-runoff is nonlinear and it is difficult to explain the existing linear rainfall-runoff. Hydrological characteristics would be utilized to apply such as hydrologic modelling or basin management. This study was effectively estimated a topographic characteristic factor of basin using the GIS. Especially, decided stream order using GIS at stream order decision that is important for input variable of GCIUH. A flash floods defined as a flood which follows shortly after a heavy or excessive rainfall event, with a few hours. In this study, we gave a definition that a critical flood for alarm is the flood when valley depth judging dangerous depth is over 0.5m depth from the bottom of channel. Result that calculate threshold discharge to use GCIUH, at the Mureung valley basin, flash flood trigger rainfall was 16.34mm in the first 20minutes when the threshold discharge was $14.54m^3/sec$.

A Study on the Urban Fringe Landscape Environment Model -The Analysis of Change in Land Uses of Chonan City using Landsat TM Data- (도농통합지역의 녹지환경정비모델에 관한 연구 I - 위성데이타를 이용한 천안시 토지이용 변화 -)

  • 심우경;이진희;김훈희
    • Journal of the Korean Institute of Landscape Architecture
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    • v.26 no.3
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    • pp.237-248
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    • 1998
  • Landcover has been largely influenced by human activities, especially in recent days. The analysis of the change of land use by urbanized development is useful for determining development plan hereafter. This study aimed to the quantitative analysis about the urban sprawl within 12 years from 1985 to 1996, at Chonan, and for extracting the characteristics of change. For this purpose, this study performed land cover classifications using Landsat TM data . A hybrid classification method was used to classify satellite images into seven types of land cover. Road network digitied from 1:25,000 topographic map was rasterized and overlaid on the landcover map. A result of this study showed that area of forest and paddy decreased due to urban sprawl. Especially from 1993 to 1996, the change of land use progressed rapidly because of merging a city and a country in Chonan. The size of patch in forest had been smaller and irregular form. It is a general progress that size of patch in forest had been smaller and irregular form. It is a general progress that the forest have changed the paddy and bare land paddy and bare land have changed low-density urban or high-density urban. This explained how urbanized Chonan was and applied the suggeston of plan in landuse with the result of this study.

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