• 대한원격탐사학회지
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• 제36권1호
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• pp.29-39
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• 2020

Forest fire is a critical disaster that causes massive destruction of forest ecosystem and economic loss. Hence, accurate estimation of the burned area is important for evaluation of the degree of damage and for preparing baseline data for recovery. Since most of the area size damaged by wildfires in Korea is less than 1 ha, it is necessary to use satellite or drone images with a resolution of less than 10m for detecting the damage area. This paper aims to detect wildfire-damaged area from a Kompsat-3 image using the indices such as NDVI (normalized difference vegetation index) and FBI (fire burn index) and to examine the classification characteristics according to the methods such as Otsu thresholding and ISODATA(iterative self-organizing data analysis technique). To mitigate the salt-and-pepper phenomenon of the pixel-based classification, a gaussian filter was applied to the images of NDVI and FBI. Otsu thresholding and ISODATA could distinguish the burned forest from normal forest appropriately, and the salt-and-pepper phenomenon at the boundaries of burned forest was reduced by the gaussian filter. The result from ISODATA with gaussian filter using NDVI was closest to the official record of damage area (56.9 ha) published by the Korea Forest Service. Unlike Otsu thresholding for binary classification,since the ISODATA categorizes the images into multiple classes such as(1)severely burned area, (2) moderately burned area, (3) mixture of burned and unburned areas, and (4) unburned area, the characteristics of the boundaries consisting of burned and normal forests can be better expressed. It is expected that our approach can be utilized for the high-resolution images obtained from other satellites and drones.

• 항공우주시스템공학회지
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• 제7권1호
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• pp.39-43
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• 2013

In this study, damage assesment and repair technique of aircraft adopted on Sandwich composite structure were performed. The sandwich composite structure were damaged by drop weight type impact test machine. The damaged sandwich composite structure was repaired using external patch repair method after removing damaged area. This study presents comparison results of the experimental investigation between the impact damaged and the repaired specimen.

• 한국환경생태학회지
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• 제27권6호
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• pp.704-717
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• 2013

본 연구는 북한산국립공원을 대상으로 참나무시들음병 피해지에 대한 감염단계별 현황을 정밀조사하고 이를 지도화하여 감염피해 관리 및 예방을 위한 기초자료를 제공하고자 하였다. 유역권을 고려한 현존식생 polygon을 맵핑단위로 설정하여 참나무류 분포지역을 조사하였으며 관리지구별 감염피해율 및 감염 단계별 가중치를 적용하여 산정한 감염지수 현황을 맵핑하였다. 북한산국립공원 전체 참나무류 감염피해율은 58.5% 이었고, 경피해율 29.6%, 중피해율 16.1%, 심피해율 8.8%, 고사율 4.1% 등 이었다. 원도봉의 범골능선에서 정릉지구의 형제봉능선까지의 감염정도가 심하였고 북한산국립공원의 주능선을 중심으로 서측의 송추지구, 산성지구, 구기지구는 상대적으로 피해정도가 약하였으나 능선부와 주요 계곡부 상부 일대에서 감염피해율은 높았다. 감염지수는 피해 미약 지역이 전체 참나무류 면적의 39.1%, 가벼운 피해 지역이 41.0%, 중간 피해 지역이 전체 면적의 16.1%, 심각한 피해 지역이 전체 면적의 3.3%, 대부분 고사 위험 피해 지역이 전체 면적의 0.4%이었다. 심피해와 고사목이 다수 확인된 도봉지구의 무수골계곡과 자운봉 일대의 감염지수가 높았으며 정릉지구의 보현봉 일대와 산성지구의 효자리계곡 일부지역에서도 감염정도가 심각하였다. 북한산국립공원의 각 지구별 참나무류 분포면적 대비 예측 감염주수 산정 결과, 전체 참나무류 주수 2,709,147주 중 감염주수는 총 1,585,937주 이었다. 우이지구가 참나무류 352,931주 중 306,161주가 감염되어 피해가 가장 심하였고 피해가 가장 적은 구기지구는 참나무류 145,747주 중 53,141주가 감염되었다.

• 한국주거학회논문집
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• 제15권6호
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• pp.115-125
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• 2004

This research is inquired to the residents in Kimcheon, Kyongsang-Boukdo and in Kangnung, Yangyang, Kangwon-Do. The residents were damaged by typhoon ${\ulcorner}RUSA{\lrcorner}$ in 2002, which occurred the biggest damage in our country's natural disaster. The result of inquiry is arranged in this research. Inquiry contents arrange a current events points through the inquiry. which is about the resident's demand and confrontation caused by a big disaster occurrence; the damage present condition which is caused by typhoon ${\ulcorner}RUSA{\lrcorner},$ the countermeasure condition on damage occurrence, the necessity content of area disaster information, the difficulty factor of damage restoration, the evaluation of the government and relation group's countermeasure which is about typhoon ${\ulcorner}RUSA{\lrcorner},$ the mental and body problem after disaster occurrence. And inquiry contents present the fundamental data for establishing the area prevention of disaster plan hereafter.

• ETRI Journal
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• 제30권4호
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• pp.506-515
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• 2008

The H.264/AVC standard has adopted new coding tools such as intra-prediction, variable block size, motion estimation with quarter-pixel-accuracy, loop filter, and so on. The adoption of these tools enables an H.264/AVC-coded bitstream to have more information than was possible with previous standards. In this paper, we propose an effective spatial error concealment method with low complexity in H.264/AVC intra-frame. From information included in an H.264/AVC-coded bitstream, we use prediction modes of intra-blocks to recover a damaged block. This is because the prediction direction in each prediction mode is highly correlated to the edge direction. We first estimate the edge direction of a damaged block using the prediction modes of the intra-blocks adjacent to a damaged block and classify the area inside the damaged block into edge and flat areas. Our method then recovers pixel values in the edge area using edge-directed interpolation, and recovers pixel values in the flat area using weighted interpolation. Simulation results show that the proposed method yields better video quality than conventional approaches.

• 한국화재소방학회논문지
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• 제20권2호
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• pp.54-63
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• 2006

최근 14년간('91-'04) 산림청에 보고된 전국 산불발생 통계자료를 변수로 SPSS Ver 13.0 프로그램을 이용하여 연도별, 월별, 시간대별, 요일별, 지역별, 피해 수종별, 원인별, 피해면적별, 진화 소요시간별 빈도분석을 실시하였다. 그 결과 연도별 산불발생건수는 2001년도에 가장 많았고, 월별로는 매년 4월에, 시간대 별로는 $14{\sim}15$시 사이에, 요일별로는 일요일에, 지역별로는 경북 > 강원 > 전남 > 경기 순으로, 피해 수종별로는 소나무림에서 가장 많이 발생하였다. 또한 원인별로는 입산자실화와 논 밭두렁소각 등이 주요 원인이지만 최근에는 방화에 의한 산불발생이 증가하는 경향이었다. 피해면적별로는 5 ha 미만의 소형 산불이 93.7%로 가장 많이 발생하는 경향이었고, 30 ha 이상의 대형 산불은 강원도 지역이 44.2%로서 가장 많이 발생하였다. 진화소요 시간별로는 30 ha 이상의 대형 산불(1,113분)이 5 ha 미만의 소형 산불(148분)보다 7.5배 더 소요되는 것으로 나타났다. 특히 대형 산불에 의한 피해면적은 건당 평균 470 ha로 나타났다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.908-910
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• 2003

In this paper the extraction method for the best suitable green vegetation area in urban area, Daegu, Korea, was developed using satellite images (1994, 1999, Landsat TM). For this, the GIS overlay analysis of GVI (Green Vegetation Index), SBI (Soil Brightness index), NWI (None-Such wetness Index) was performed to estimate the best suitable green vegetation area. Also, the statistical documents, algorithm and Tasseled-Cap index were used to recognize the change of land cover such as cultivation area, urban area, and damaged area. Through the result of this study, it is possible to monitor the large sized reclamation of land by drainage or damaged area by forest fires. Moreover, information with the change of green vegetation and the status of cultivation by GVI, but also moisture content by percentage by NWI and surface class by SBI can be obtained.

• 한국BIM학회 논문집
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• 제9권1호
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• pp.11-21
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• 2019

Recently, there is an increase in fire incidents in building structures. Due to this, the importance of fire-damaged buildings' safety diagnosis and evaluation after fire is growing. However, the existing fire-damaged safety diagnosis and evaluation methods are personnel-oriented, so the diagnostic results are intervened by investigators' subjectivity and unquantified. Thus, improper repair and reinforcement can result in secondary damage accidents and economic losses. In order to overcome these limitations, this study proposes using 3D laser scanning technology. The case analysis of fire-damaged building structures was conducted to verify the effectiveness of accuracy and manpowering by comparing the existing method and the proposed method. The proposed method using 3D laser scanning technology to obtain point cloud data of fire-damaged field. The point cloud data and BIM model is combined to inspect the fire-damaged area and depth. From inspection, quantified repair and reinforcement quantity take-off can be acquired. Also, the proposed method saves half of the manpowering within same time period compared to the existing method. Therefore, it seems that using 3D laser scanning technology in fire-damaged safety diagnosis and evaluation will improve in accuracy and saving time and manpowering.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2020년도 학술발표회
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• pp.4-4
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• 2020

Three wildfires severely damaged local towns and forests in Gangwon-do, South Korea in 2019 April 4-5. Local hydrological regime could be greatly altered by the wildfires, therefore it is important to assess its damage (e.g. area and severity) and also resultant changes in hydrological fluxes. We retrieved the Normalized-Burned Ratio (NBR) index using remote-sensing data (Moderate Resolution Imaging Spectroradiometer (MODIS) 500-m 8-day surface reflectance data), and delineated the damaged-area based on the difference in the NBR (dNBR) before and after the wildfires. We then estimated changes in the annual evapotranspiration (AET) in 2019 using the MODIS evapotranspiration data (500-m 8-day). It was found that the damaged-area of the three wildfires was 29.50 km^2 in total, which take up 1.00-6.19% area of five catchments. It was estimated that the AET would be decreased as 0.05-1.56% over those five catchments, as compared to the pre-fire AET (2004-2018). The impact of the wildfires on the catchment AET was less severe than expected (i.e. up to 1.56%) mostly because two big wildfires were distributed across two catchments respectively (i.e. four catchments for the two wildfires) and the other wildfire was small and not severe. This study highlights the importance of assessing the area and severity of a wildfire when estimating its impact on the local hydrological cycle.

• 한국안전학회지
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• 제37권4호
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• pp.101-112
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• 2022

Expanding urbanization practices result in high numbers of buildings being developed in city centers. This high building concentration leads to an increased fire risk, resulting in higher casualty rates and increased economic damages compared to fires in the past. The purpose of this study was to analyze the structural behavior of fire-damaged reinforced concrete buildings using analytical methods and to suggest methods of improving fire resistance in the event of a fire. Damage levels were measured using commercial software to apply the finite element method, ABAQUS, and MIDAS GEN to the dataset. Load-deflection curves were calculated using the effective area and moment of inertia of the fire-damaged columns provided by ABAQUS. The results of this analysis indicate that fire-damaged beams with experience greater deflection from indoor fires than they will from outdoor fires. Fires that occurred on the middle floors were more dangerous than those occurring on higher floors, and eccentrically loaded columns experienced more damage than axially loaded columns. The results indicate that these methods accurately predict structural behaviors of fire damaged concrete columns by considering fire exposure area and eccentric loading.