• The Journal of Engineering Geology
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• v.16 no.3 s.49
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• pp.255-263
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• 2006

In an electrical tomographic survey using an inclined borehole with a pole-dipole array, we must consider several factors: a singular point associated with zero potential difference, a spatial discrepancy between electrode and nodal point in a model due to a inclined borehole, and a variation of geometric factors in connection with a irregular topography. Singular points which are represented by the normal distance from current source to the ground surface can be represented by serveral regions due to a irregular topography of ground surface. The method of element division can be applied to the region in which the borehole is curved, inclined or the distance between the electrodes is shorter than that of nodal points, because the coordinate of each electrode cannot be assigned directly to the nodal point if several electrodes are in an element. Test on a three-dimensional (3-D) synthetic model produces good images of conductive target and shoves stable convergence.

• Proceedings of the KGS Conference
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• 2002.11a
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• pp.97-100
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• 2002

지표의 기복은 암석의 차별적 풍화와 침식을 반영하므로, 기복의 형성에서 암석이 차지하는 몫을 이해하는 것은 중요하며 이 문제는 근대지형학의 발달 초기부터 중요하게 다루어져 왔다(권혁재, 2002).(Picture Omitted) 대구분지 북쪽 분수계를 이루고 있는 팔공산의 기반암은 중생대 백악기 말부터 제 3기초기에 걸쳐 백악기 퇴적암인 경상누층군을 관입하여 형성된 불국사화강암이다.(중략)

• Journal of Korea Water Resources Association
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• v.55 no.spc1
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• pp.1223-1234
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• 2022

Efforts for reducing greenhouse gas emission coping with climate change have also been performed in the field of water and wastewater works. In particular, the technical development for reducing energy has been applied in operating water distribution system. The reduction of energy in water distribution system can be achieved by reducing structural loss induced by topographic variation and operational loss induced by leakage and friction. However, both analytical and numerical approaches for analyzing energy budget of water distribution system has been challengeable because energy components are affected by the complex interaction of affecting factors. This research drew mathematical equations for 5 types of state (hypothetical, ideal, leak-included ideal, leak-excluded real, and real), which depend on the assumptions of topographic variation, leakage, and friction. Furthermore, the derived equations are schematically illustrated and applied into simple water network. The suggested method makes water utilities quantify, classify, and evaluate the energy of water distribution system.

• Journal of the Speleological Society of Korea
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• v.34 no.35
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• pp.23-31
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• 1993

환선굴은 이른바 복합형이면서도 토출형의 석회동굴이다. 동굴내 지형의 기복이 다양하고 동굴 내부에 수많은 대소의 폭포와 여울이 걸려 있는 동굴유가 풍부한 동굴이며 동굴의 2차생성물은 이 동굴의 지표면을 이루고 있는 지층이 빈약하므로 2차생성물의 성장이 활발하지 못한 동굴이다. 동굴 천정의 지층 구조로 보아 제 Ⅰ지구에서는 비교적 이차생성물이 발달되고 있으나 그밖의 동굴 내부지역에서는 발달이 미약하다.(중략)

• Journal of The Geomorphological Association of Korea
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• v.17 no.3
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• pp.49-57
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• 2010

The topographical rolling distribution characteristics of 10 geological areas in Gyeongsangbuk-do are analyzed using GIS. PEs, PEgrgn, Pp₂, Kav·Kiv, and Khgr regions occupy the more than 60% that are a steep slope-a high elevation and a steep slope-a middle elevation region, and form high moutains in Gyeongsangbuk-do. Meanwhile, Ke_1-9 and Te_1-2 regions take possession of the more than 70% that are a low elevation region. Ke_1-9 region form landward flatlands and hills around Nakdong river and tributaries of Nakdong river in Gyeongsangbuk-do. Then, Te_1-2 region form coastal lowlands adjacent the East sea in Gyeongsangbuk-do. Also, Jgr region take possession of the more than 70% that are a middle elevation region, and form low moutains or flatlands in Gyeongsangbuk-do. Finally, Ols₁ region take possession of the more than 50% that are a steep slope region, and form landward moutains in Gyeongsangbuk-do.

• Korean Journal of Remote Sensing
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• v.39 no.5_1
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• pp.637-654
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• 2023

In recent years, the number of users has been increasing with the rapid development of earth observation satellites. In response, the Committee on Earth Observation Satellites (CEOS) has been striving to provide user-friendly satellite images by introducing the concept of Analysis Ready Data (ARD) and defining its requirements as CEOS ARD for Land (CARD4L). In ARD, a mask called an Unusable Data Mask (UDM), identifying unnecessary pixels for land analysis, should be provided with a satellite image. UDMs include clouds, cloud shadows, terrain shadows, etc. Terrain shadows are generated in mountainous terrain with large terrain relief, and these areas cause errors in analysis due to their low radiation intensity. previous research on terrain shadow detection focused on detecting terrain shadow pixels to correct terrain shadows. However, this should be replaced by the terrain correction method. Therefore, there is a need to expand the purpose of terrain shadow detection. In this study, to utilize CAS500-4 for forest and agriculture analysis, we extended the scope of the terrain shadow detection to shaded areas. This paper aims to analyze the potential for terrain shadow detection to make a terrain shadow mask for South and North Korea. To detect terrain shadows, we used a Hill-shade algorithm that utilizes the position of the sun and a surface's derivatives, such as slope and aspect. Using RapidEye images with a spatial resolution of 5 meters and Sentinel-2 images with a spatial resolution of 10 meters over the Korean Peninsula, the optimal threshold for shadow determination was confirmed by comparing them with the ground truth. The optimal threshold was used to perform terrain shadow detection, and the results were analyzed. As a qualitative result, it was confirmed that the shape was similar to the ground truth as a whole. In addition, it was confirmed that most of the F1 scores were between 0.8 and 0.94 for all images tested. Based on the results of this study, it was confirmed that automatic terrain shadow detection was well performed throughout the Korean Peninsula.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.04a
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• pp.153-154
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• 2000

광양만권은 전남 동부의 연안부에 위치하며, 중화학공업, 제철산업 및 대규모적인 물류센터가 건설되고있다. 이 지역의 해안선은 복잡하며, 지형의 기복도 심하다. 때문에, 대기오염물짙이 지형에 따른 확산범위 및 변화량을 사전에 평가하는 것이 이 지역의 대기환경보전을 위해 매우 중요하다. 따라서, 본 연구는 광양만권을 대상으로 지형의 유무에 따른 기상장의 예측 및 대기오염물질의 확산에 대한 평가를 실시하였다.(중략)

• 한국지형공간정보학회:학술대회논문집
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• 2002.03a
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• pp.48-53
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• 2002

본 연구에서는 각각 1998년 8월 12일(홍수 발생시), 8월 19일(홍수 발생 후) 옥천, 보은 지역을 촬영한 RADARSAT SAR 위성영상을 이용하여 수계지역 및 홍수지역 분류를 수행하고자 하였다. 이를 위해, 먼저 두 장의 위성영상에 대해서 각각 스페클 잡영(speckle noise)을 제거하고, ${\sigma}^0$(sigma naught, dB)을 계산한 후 수계지역에 대한 ${\sigma}^0$값을 분석하였다. 이 값을 기준으로 각각 두 장의 위성영상에서 각각 최대우도법을 이용하여 수계지역을 분류하였다. SAR 영상은 영상취득의 원리에 의해 지형의 기복에 따른 음영효과(shadow effect)가 발생하는데, 음영효과가 발생하는 지역의 ${\sigma}^0$값은 수계지역과 비슷한 반사특성(낮은 dB 값)을 보인다. 따라서 지형의 기복이 심한 지역의 수계지역 분류시 음영효과를 제거해야 효과적적인 분류를 할 수 있으며, 이를 위해 위성의 헤더자료로부터 촬영시 각각의 촬영중심을 계산하고, 촬영중심과 지상좌표와의 기하학적 관계를 고려하여 음영효과를 제거하였다. 마지막으로, 수계지역만이 추출된 영상에 대해 영상의 기하보정을 수행하였으며, 기하 보정된 두장의 위성영상에 대해 차분영상를 생성함으로서 홍수지역을 분류하였다.

• Journal of the Korean Association of Geographic Information Studies
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• v.12 no.1
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• pp.64-72
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• 2009

The method to generate a digital elevation model(DEM) from contour lines causes a problem in which the low relief landform cannot be clearly presented due to the fact that it is significantly influenced by the expression of micro landform elements according to the interval of contours. Thus, this study attempts to develop a landcover burning method that recovers the micro relief landform of the DEM, which applies buffering and map algebra methods by inputting the elevation information to the landcover. In the recovering process of the micro landform, the DEM was recovered using the buffering method and elevation information through the map algebra for the landcover element for the micro landform among the primary DEM generation, making landcover map, and landcover elements. The recovering of the micro landform was applied based on stream landforms. The recovering of landforms using the buffering method was performed for the bar, which is a polygonal element, and wetland according to the properties of concave/convex through generating contours with a uniform interval in which the elevation information applied to the recovered landform. In the case of the linear elements, such as bank, road, waterway, and tributary, the landform can be recovered by using the elevation information through applying a map algebra function. Because the polygonal elements, such as stream channel, river terrace, and artificial objects (farmlands) are determined as a flat property, these are recovered by inputting constant elevation values. The results of this study were compared and analyzed for the degree of landform expression between the original DEM and the recovered DEM. In the results of the analysis, the DEM produced by using the conventional method showed few expressions in micro landform elements. The method developed in this study well described wetland, bar, landform around rivers, farmland, bank, river terrace, and artificial objects. It can be expected that the results of this study contribute to the classification and analysis of micro landforms, plain and the ecology and environment study that requires the recovering of micro landforms around streams and rivers.

• 한국지형공간정보학회:학술대회논문집
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• 2003.09a
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• pp.101-106
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• 2003