• Korean Journal of Remote Sensing
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• v.36 no.1
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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.

• Journal of Aerospace System Engineering
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• v.7 no.1
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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.

• Korean Journal of Environment and Ecology
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• v.27 no.6
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• pp.704-717
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• 2013

This study aims to provide basic data for management and prevention of infection damage by Oak wilt disease through mapping method of status with infected level in damaged area of Bukhansan National Park. Survey was carried out in the distributed area of oak trees with mapping unit of polygon of actual vegetation and mapped of infection ratio and infection index applying weight according to infected level. Infection ratio of oak trees in Bukhansan National Park was 58.5%, and lightly damaged ratio was 29.6%, half of the damaged ratio was 16.1%, seriously damaged ratio was 8.8% and withered ratio was 4.1%. It was serious to be infected from Beomgol ridge in Wondobong district to Hyeongjaebong in Jeongrung district. Although the infected ratio of the western part of Songchu district, Sanseong district and Gugi district centering main ridge of Bukhansan National Park was low, it of ridge and main valley was high. Infection index of hardly damaged area was 39.1% of whole area, and slightly damaged area was 41.0%, half of the damaged area was 16.1%, seriously damaged area was 3.3% and alarmed withering area was 0.4%. Infection index was high around Musugol valley in Dobong district and Jaunbong, and it of Bohyunbong of Jeongrung district and the part of Hyojari valley of Sanseong district was serious. Predicted numbers of the trees affected Oak wilt disease compared to the distributed area of oak trees was 1,585,937 trees among 2,709,147 trees of Quercus spp. 352,931 trees among the 306,161 trees of oak were infected in Woi district, the most seriously infected area and 53,141 trees among the 145,747 trees of oak was infected in Gugi district, the most slightly infected area.

• Journal of the Korean housing association
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• v.15 no.6
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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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• v.30 no.4
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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.

• Fire Science and Engineering
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• v.20 no.2 s.62
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• pp.54-63
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• 2006

The number of forest fire under various conditions such as year, month, time, day of the week, region, damaged species, cause, and damaged area are checked, and the statistics of the forest fire causing materials in recent 14 years ('91-'04) are analyzed. The result shows that the year majority of forest fires had happened in last 14 year was 2001 and most of forest fire occurred in April, Sunday, around 14:00 to 15:00. The most damaged region is Gyeongsangbuk-Do, followed by Gangwon-Do, Jeollabuk-Do, and Gyeonggi-Do. The most damaged species is pine tree. The main causes of forest fires are accidental fire and incineration of a field boundary; however, recently, incendiarism is increased. The result of analysis on the damaged area shows that small fires under 5 ha occurred most frequently and large fires (over 30 ha) occurred mostly in Kangwon province (44.2%). The result also shows that the large forest fires (1,113 minutes) require 7.5 time more than the small forest fires (148 minutes). Especially, since average damaged area caused by large forest fire was about 470 ha per incident.

• Proceedings of the KSRS Conference
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• 2003.11a
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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.

• Journal of KIBIM
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• v.9 no.1
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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.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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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.

• Journal of the Korean Society of Safety
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• v.37 no.4
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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.