위성영상과 음영기복도를 이용한 오대산 지역 진앙의 위치와 선구조선의 관계 분석

차성은 ( Sung-eun Cha ),지광훈 ( Kwang-hoon Chi ),조현우 ( Hyun-woo Jo ),김은지 ( Eun-ji Kim ),이우균 ( Woo-kyun Lee ) 한국지리정보학회 2016 한국지리정보학회지 Vol.19 No.4

본 연구에서는 LANDSAT 8호, KOMPSAT 2호 위성영상과 1/25,000 수치지형도를 기반으로 작성된 음영기복도를 이용하여 2007년 1월 20일 오대산 지역에서 발생한 약 4.8의 중규모 지진과 선구조선의 관계를 분석하였다. 대부분의 선행연구는 지체구조와 관련된 선구조선 분석 연구를 하였으며, 주로 2차원의 위성영상과 음영기복도를 활용하였기에 지형의 기복 등에 대한 판독이 어려워 선구조선 추출이 제한적이었다. 본 연구에서는 이를 보완하기 위해 수치표고모델(Digital Elevation Model; DEM)을 기반으로 작성한 3차원 입체 영상과 수계망 분석을 통해 지형의 기복, 수계의 연결성 등을 판독해 선구조선을 추출하여, 2차원 영상에서 나타나는 시각적인 판독에 의한 오류를 최소화한 선구조선 판독도를 작성하였다. 또한 진앙에 대한 선구조선의 통계 요소별 밀도를 추정하기 위해 spline 내삽법을 이용하여 선구조선의 빈도, 교차점, 길이에 대한 밀도를 계산하였다. 그리고 진앙에서의 선구조선 밀도가 얼마나 밀집되어 있는지 정량적으로 표현하기 위하여 각 격자 내의 선구조선 밀도에 대해 최대 선구조선 밀도로 나누는 상대밀도 값(Value of the Relative Density; VRD)을 계산하는 알고리즘을 개발하여 밀도도(density map)를 작성하였다. 각 영상의 진앙에서의 VRD는 최소 약 0.60에서 최대 약 0.90으로 나타났지만, 각 영상별 광원의 고도각과 방위각이 차이가 있어 영상별 VRD보다 통계 요소별 VRD의 평균치를 사용하였다. 그 결과, 빈도의 평균 VRD는 약 0.85로 교차점과 길이의 평균 VRD보다 약 21% 높게 나타나, 선구조선의 빈도 요소가 진앙의 위치와의 관계가 가장 밀접함을 확인하였다. 이와 같이 3차원 영상의 선구조선 추출을 통한 밀도 분석 기술은 향후 지진 발생 가능 지역 분석에 기초자료로써의 의미가 있을 것으로 기대된다. The purpose of this paper is to analyze the relationship between the location of the epicenter of a medium-sized earthquake(magnitude 4.8) that occurred on January 20, 2007 in the Odaesan area with lineament features using a shaded relief map(1/25,000 scale) and satellite images from LANDSAT-8 and KOMPSAT-2. Previous studies have analyzed lineament features in tectonic settings primarily by examining two-dimensional satellite images and shaded relief maps. These methods, however, limit the application of the visual interpretation of relief features long considered as the major component of lineament extraction. To overcome some existing limitations of two-dimensional images, this study examined three-dimensional images, produced from a Digital Elevation Model and drainage network map, for lineament extraction. This approach reduces mapping errors introduced by visual interpretation. In addition, spline interpolation was conducted to produce density maps of lineament frequency, intersection, and length required to estimate the density of lineament at the epicenter of the earthquake. An algorithm was developed to compute the Value of the Relative Density(VRD) representing the relative density of lineament from the map. The VRD is the lineament density of each map grid divided by the maximum density value from the map. As such, it is a quantified value that indicates the concentration level of the lineament density across the area impacted by the earthquake. Using this algorithm, the VRD calculated at the earthquake epicenter using the lineament``s frequency, intersection, and length density maps ranged from approximately 0.60(min) to 0.90(max). However, because there were differences in mapped images such as those for solar altitude and azimuth, the mean of VRD was used rather than those categorized by the images. The results show that the average frequency of VRD was approximately 0.85, which was 21% higher than the intersection and length of VRD, demonstrating the close relationship that exists between lineament and the epicenter. Therefore, it is concluded that the density map analysis described in this study, based on lineament extraction, is valid and can be used as a primary data analysis tool for earthquake research in the future.

국내 COVID-19의 공간분포특성 분석

차성은(Cha, Sung Eun),조정선(Jo, Jeong Seon),조정은(Jo, Jeong Eun),이우균(Lee, Woo Kyun),김대철(Kim, Dae Cheol) 대한공간정보학회 2021 대한공간정보학회지 Vol.29 No.2

수도권 집중호우에 따른 산사태 발생 위험지역 분석

차성은(Cha, Sung Eun),임철희(Lim, Chul Hee),김지원(Kim, Ji Won),김문일(Kim, Moon Il),송철호(Song, Chol Ho),이우균(Lee, Woo Kyun) 대한공간정보학회 2018 대한공간정보학회지 Vol.26 No.3

본 연구는 산사태 위험지도의 정확도를 향상시킬 수 있는 방안을 모색하기 위해, 2011년 7월 26일부터 28일까지 서울지역에서 집중호우 시 발생한 산사태를 바탕으로 지형공간 및 기상인자를 이용해 산사태 위험지도를 작성하였다. 그 결과, 서울지역의 지형공간 및 기상인자를 모두 고려한 통합된 산사태 위험지도에서는 총 19회의 산사태중 18회(약 95%)가 높은 산사태 위험 지역(high landslide risk area; HLRA)에서, 나머지 1회(약 5%)는 중간 산사태 위험 지역(medium landslide risk area; MLRA)에서 발생하였다. 이를 통해 본 연구에서 지형공간인자를 기반으로 도출한 산사태 위험지역은 실제 집중호우 발생 시 산사태 발생 위험이 상당히 높아짐을 확인하였다. This study aims to find the method to enhance the accuracy of landslide risk map. The landslide risk map was produced based on the landslides occurred during heavy rainfall events from July 26 to 28 in 2011. For the landslide risk map, geospatial and climate factors were used. As a result, in the integrated landslide risk map of Seoul, which considered geospatial factors and climate factors, 18 out of 19 landslides (about 95%) occurred in the high landslide risk area (HLRA) and remaining one (about 5%) was in the medium landslide risk area (MLRA). These results show that the risk of landslides is significantly increased if the climate is exposed to the landslide hazard area analyzed by geospatial factors.

원격탐사자료를 이용한 참나무시들음병 피해목의 공간분포특성 분석

차성은,이우균,김문일,이슬기,조현우,최원일,Cha, Sungeun,Lee, Woo-Kyun,Kim, Moonil,Lee, Sle-Gee,Jo, Hyun-Woo,Choi, Won-Il 한국산림과학회 2017 한국산림과학회지 Vol.106 No.3

This study categorized the damaged trees by Supervised Classification using time-series-aerial photographs of Bukhan, Cheonggae and Suri mountains because oak wilt disease seemed to be concentrated in the metropolitan regions. In order to analyze the spatial characteristics of the damaged areas, the geographical characteristics such as elevation and slope were statistically analyzed to confirm their strong correlation. Based on the results from the statistical analysis of Moran's I, we have retrieved the following: (i) the value of Moran's I in Bukhan mountain is estimated to be 0.25, 0.32, and 0.24 in 2009, 2010 and 2012, respectively. (ii) the value of Moran's I in Cheonggye mountain estimated to be 0.26, 0.32 and 0.22 in 2010, 2012 and 2014, respectively and (iii) the value of Moran's I in Suri mountain estimated to be 0.42 and 0.42 in 2012 and 2014. respectively. These numbers suggest that the damaged trees are distributed in clusters. In addition, we conducted hotspot analysis to identify how the damaged tree clusters shift over time and we were able to verify that hotspots move in time series. According to our research outcome from the analysis of the entire hotspot areas (z-score>1.65), there were 80 percent probability of oak wilt disease occurring in the broadleaf or mixed-stand forests with elevation of 200~400 m and slope of 20~40 degrees. This result indicates that oak wilt disease hotspots can occur or shift into areas with the above geographical features or forest conditions. Therefore, this research outcome can be used as a basic resource when predicting the oak wilt disease spread-patterns, and it can also prevent disease and insect pest related harms to assist the policy makers to better implement the necessary solutions.

농림위성 활용을 위한 산불 피해지 분류 딥러닝 알고리즘 평가

차성은,원명수,장근창,김경민,김원국,백승일,임중빈,Cha, Sungeun,Won, Myoungsoo,Jang, Keunchang,Kim, Kyoungmin,Kim, Wonkook,Baek, Seungil,Lim, Joongbin 대한원격탐사학회 2022 대한원격탐사학회지 Vol.38 No.6

Recently, forest fires have frequently occurred due to climate change, leading to human and property damage every year. The forest fire monitoring technique using remote sensing can obtain quick and large-scale information of fire-damaged areas. In this study, the Gangneung and Donghae forest fires that occurred in March 2022 were analyzed using the spectral band of Sentinel-2, the normalized difference vegetation index (NDVI), and the normalized difference water index (NDWI) to classify the affected areas of forest fires. The U-net based convolutional neural networks (CNNs) model was simulated for the fire-damaged areas. The accuracy of forest fire classification in Donghae and Gangneung classification was high at 97.3% (f₁=0.486, IoU=0.946). The same model used in Donghae and Gangneung was applied to Uljin and Samcheok areas to get rid of the possibility of overfitting often happen in machine learning. As a result, the portion of overlap with the forest fire damage area reported by the National Institute of Forest Science (NIFoS) was 74.4%, confirming a high level of accuracy even considering the uncertainty of the model. This study suggests that it is possible to quantitatively evaluate the classification of forest fire-damaged area using a spectral band and indices similar to that of the Compact Advanced Satellite 500 (CAS500-4) in the Sentinel-2.

핫스팟 분석을 통한 거창지역의 선구조선과 진앙의 상관관계 분석

조현우,지광훈,차성은,김은지,이우균,Jo, Hyun-Woo,Chi, Kwang-Hoon,Cha, Sungeun,Kim, Eunji,Lee, Woo-Kyun 대한원격탐사학회 2017 대한원격탐사학회지 Vol.33 No.5

This study aims to understand the relationship between lineaments and epicenters in Geochang region, Gyungsangnam-do, South Korea. An instrumental observation of earthquakes has been started by Korea Meteorological Administration (KMA) since 1978 and there were 6 earthquakes with magnitude ranging 2 to 2.5 in Geochang region from 1978 to 2016. Lineaments were extracted from LANDSAT 8 satellite image and shaded relief map displayed in 3-dimension using Digital Elevation Model (DEM). Then, lineament density was statistically examined by hotspot analysis. Hexagonal grids were generated to perform the analysis because hexagonal pattern expresses lineaments with less discontinuity than square girds, and the size of the grid was selected to minimize a variance of lineament density. Since hotspot analysis measures the extent of clustering with Z score, Z scores computed with lineaments' frequency ($L_f$), length ($L_d$), and intersection ($L_t$) were used to find lineament clusters in the density map. Furthermore, the Z scores were extracted from the epicenters and examined to see the relevance of each density elements to epicenters. As a result, 15 among 18 densities,recorded as 3 elements in 6 epicenters, were higher than 1.65 which is 95% of the standard normal distribution. This indicates that epicenters coincide with high density area. Especially, $L_f$ and $L_t$ had a significant relationship with epicenter, being located in upper 95% of the standard normal distribution, except for one epicenter in $L_t$. This study can be used to identify potential seismic zones by improving the accuracy of expressing lineaments' spatial distribution and analyzing relationship between lineament density and epicenter. However, additional studies in wider study area with more epicenters are recommended to promote the results.

화학사고에 의한 국내 농작물 피해 평가를 위한 사례연구

박민석(Minseok Park),차성은(Sungeun Cha),송용재(Yong Jae Song),손경영(Kyoung young Son),현승훈(Seunghun Hyun) 한국토양비료학회 2016 한국토양비료학회 학술발표회 초록집 Vol.2016 No.10

원격탐사와 지리정보시스템의 산림분야 활용

이우균,김문일,송철호,이슬기,차성은,김강선,Lee, Woo-Kyun,Kim, Moonil,Song, Cholho,Lee, Sle-gee,Cha, Sungeun,Kim, GangSun 한국국토정보공사 공간정보연구원 2016 지적과 국토정보 Vol.46 No.2

Forest accounts for almost 64 percents of total land cover in South Korea. For inventorying, monitoring, and managing such large area of forest, application of remote sensing and geographic information system (RS/GIS) technology is essential. On the basis of spectral characteristics of satellite imagery, forest cover and tree species can be classified, and forest cover map can be prepared. Using three dimensional data of LiDAR(Light Detection and Ranging), tree location and tree height can be measured, and biomass and carbon stocks can be also estimated. In addition, many indices can be extracted using reflection characteristics of land cover. For example, the level of vegetation vitality and forest degradation can be analyzed with VI (vegetation Index) and TGSI (Top Grain Soil Index), respectively. Also, pine wilt disease and o ak w ilt d isease c an b e e arly detected and controled through understanding of change in vegetation indices. RS and GIS take an important role in assessing carbon storage in climate change related projects such as A/R CDM, REDD+ as well. In the field of climate change adaptation, impact and vulnerability can be spatio-temporally assessed for national and local level with the help of spatio-temporal data of GIS. Forest growth, tree mortality, land slide, forest fire can be spatio-temporally estimated using the models in which spatio-temporal data of GIS are added as influence variables.

농림위성 산림분야 식생지수 검보정 사이트 설계

임중빈 ( Joongbin Lim ),차성은 ( Sungeun Cha ),원명수 ( Myoungsoo Won ),김준 ( Joon Kim ),박주한 ( Juhan Park ),류영렬 ( Youngryel Ryu ),이우균 ( Woo-kyun Lee ) 대한원격탐사학회 2022 대한원격탐사학회지 Vol.38 No.3

The Compact Advanced Satellite 500-4 (CAS500-4) is under development to efficiently manage and monitor forests in Korea and is scheduled to launch in 2025. The National Institute of Forest Science is developing 36 types of forestry applications to utilize the CAS500-4 efficiently. The products derived using the remote sensing method require validation with ground reference data, and the quality monitoring results for the products must be continuously reported. Due to it being the first time developing the national forestry satellite, there is no official calibration and validation site for forestry products in Korea. Accordingly, the author designed a calibration and validation site for the forestry products following international standards. In addition, to install calibration and validation sites nationwide, the authors selected appropriate sensors and evaluated the applicability of the sensors. As a result, the difference between the ground observation data and the Sentinel-2 image was observed to be within ±5%, confirming that the sensor could be used for nationwide expansion.

공장 혈관이형성증

김경영(Gyeong Young Kim),김나영(Na Young Kim),전호춘(Ho Choon Jeon),차성은(Sung Eun Cha),김지영(Ji Young Kim),이계희(Kye Heui Lee),양대현(Dae Hyun Yang),박경주(Gyung Joo Park),최신은(Shin Eun Choi) 대한소화기학회 1995 대한소화기학회지 Vol.27 No.5

Angiodysplasia, an important vascular lesion of the gut, defined by the presence of ectasia of normal preexisting intestinal submucosal veins and overlying mucosal capillaries, is a source of major morbidity from bleeding. With the development of diagnostic angiography, angiodysplasia of the bowel has been recognized as a frequent cause of significant intestinal bleeding, particularly in elderly patients. Its cause is unknown but considered mostly to be acquired as a result of a degenerative process associated with aging. We experienced one case of jejunal angiodysplasia in a 64-year old man, diagnosed by angiography, and selective jejunal resection was conducted with the aid of intraoperative mesenteric arterial methylene blue injection, administered via a catheter superselectively positioned in the appropriate jejunal arterial branch prior to operation. This patient has been followed up for 6 months without rebleeding. (Korean J Gastroenterol 1995;27:588- 594)