• 대한원격탐사학회지
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• 제35권4호
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• pp.517-534
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• 2019

In abrupt fire disturbances, high quality images suitable for wildfire damage assessment can be difficult to acquire. Quantifying wildfire burn area and severity are essential measures for quick short-term disaster response and efficient long-term disaster restoration. Planetscope (PS) imagery offers 3 m spatial and daily temporal resolution, which can overcome the spatio-temporal resolution tradeoff of conventional satellites, albeit at the cost of spectral resolution. This study investigated the potential of augmenting PS imagery by integrating the spectral information from Sentinel-2 (S2) differenced Normalized Burn Ratio (dNBR) to PS differenced Normalized Difference Vegetation Index (dNDVI) using histogram matching,specifically for wildfire burn area and severity assessment of the Okgye wildfire which occurred on April 4th, 2019. Due to the difficulty in acquiring reference data, the results of the study were compared to the wildfire burn area reported by Ministry of the Interior and Safety. The burn area estimates from this study demonstrated that the histogram-matched (HM) PS dNDVI image produced more accurate burn area estimates and more descriptive burn severity intervals in contrast to conventional methods using S2. The HM PS dNDVI image returned an error of only 0.691% whereas the S2 dNDVI and dNBR images overestimated the wildfire burn area by 5.32% and 106%, respectively. These improvements using PS were largely due to the higher spatial resolution, allowing for the detection of sparsely distributed patches of land and narrow roads, which were indistinguishable using S2 dNBR. In addition, the integration of spectral information from S2 in the PS image resolved saturation effects in areas of low and high burn severity.

• 대한치과교정학회지
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• 제25권6호
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• pp.655-664
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• 1995

Sixty male patients with polysomnographically documented OSA were included in this study. A pair of cephalograms were obtained in the upright and supine positions. In the supine position, the ANB angle, lower facial height and the cross-sectional area of soft palate increased and there was a decrease in the vertical airway length and oropharynx cross-sectional area. Positional changes did not affect the cross-sectional area of tongue, but the cross-sectional area of the oropharynx decreased in the supine position. The obese group had higher AI and RDI. Maxillary unit length, C3-H, the cross-sectional areas of tongue, soft palate and oropharynx were significantly greater in the group Obese than in non-obese group. No correlation was noted between the mandibular unit length and OSA severity, The group of small mandibular unit length showed shorter lower facial height and maxillary unit length, and smaller cross-sectional area of tongue than the long mandibular unit length group. Hyold bone positioned more inferiorly and cross-sectional area of nasopharynx decreased as the OSA severity increased.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.321-322
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• 2015

An area of severity (AOS) assessment is defined as a set of the fault positions that can result in the voltage sag bigger than certain level for sensitive buses simultaneously. Using the AOS assessment, the location of devices for compensating voltage sag can be determined as the site expected to less voltage sag at the sensitive bus. The energy storage system based on the control strategy emulating the traditional synchronous generator can contribute the fault current with fast response. Therefor are of venerability (AOV) can be reduced. The energy storage system installed by the AOS assessment has function which can experience relatively less voltage sag in addition to the conventional role of energy storage.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.323-324
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• 2015

Voltage sag phenomenon is known as one of the important problems that brought huge economic losses in the modern industry. The voltage sag assessment is to predict an annual expected sag frequency (ESF) at concerned consumers caused by fault in the system. An area of severity (AOS) assessment is defined as a set of the fault positions that can result in the voltage sag bigger than certain level for multi-concerned buses simultaneously. This paper introduces how to determine a method for evaluating the voltage sag performance based on the AOS assessment.

• 한국임상수의학회지
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• 제27권6호
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• pp.686-692
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• 2010

컴퓨터 단층촬영술(computed tomography; CT)은 인의에서 췌장염의 진단 기준으로 이용되고 있으며, Balthazar CT severity index (CTSI)는 CT 영상을 바탕으로 췌장 괴사 부위를 측정하여 췌장염의 심각도를 평가하는 지수이다. 본 연구에서는, 25마리의 비글견을 정상 그룹과 대조군, 자가 담즙 주입을 통해 급성 괴사성 췌장염을 유발한 실험군으로 나누어 Balthazar CTSI 측정 결과와 조직 검사 결과를 비교하였다. 정상 개의 췌장의 Hounsfield unit (HU)은 $52.44{\pm}4.58$ 이었고, 급성 괴사성 췌장염에서는 유의적으로 감소하였다(P < .05). 조영 증강 CT 영상에서 확인한 췌장 실질의 괴사 부위를 찾아 Balthazar CTSI를 계산한 결과 조직 검사 결과와 밀접한 상관 관계를 보였으며, 민감도 100%, 특이도 88.89%로 확인되었다. Balthazar CTSI는 급성 췌장염이 발생한 개에서 심각도 평가에 유용한 방법으로 판단된다.

• 한국측량학회지
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• 제28권1호
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• pp.21-28
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• 2010

산불은 산림의 주요 교란요소중의 하나로써 산림 구조와 기능에 매우 큰 영향을 미치며, 산불피해강도에 따라 피해 후 식생회복 과정이 달라질 수 있다. 산불피해지의 피해강도와 식생회복 과정을 파악하기 위해서는 많은 인력과 예산이 필요하다. 위성영상자료를 이용한 산불피해지의 피해량 분석은 신속한 정보는 물론 대규모 피해지의 객관적인 결과를 원격으로 신속하게 취득할 수 있다. 이에 본 연구에서는 충청남도 청양 예산 지역의 산불발생 전 후 위성영상을 이용한 분류 기법을 통해 연구대상 지역의 산불피해 정보를 산출하고자 하였다. 이를 위해 산불발생 전 후의 다 시기 Landsat 위성영상을 이용한 영상 분류를 통해 산불피해 지역의 면적을 산출하였으며 수치임상도와의 중첩분석을 통해 피해지역 삼림의 수종, 영급, 경급 및 수관밀도별 피해량을 효과적으로 산정할 수 있었으며 분류결과와 NDVI를 이용하여 식생회복을 모니터링 할 수 있었다.

• The Plant Pathology Journal
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• 제16권5호
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• pp.257-263
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• 2000

Infection with rice blast fungus (Magnaporthe grisea) significantly reduced foliar net photosynthesis (A) of rice cultivars: Ilpoom, Hwasung, and Choochung in greenhouse experiments. By measuring the amount of diseased leaf area with a computer image analysis system, the relation between disease severity (DS) and net photosynthetic rate was curvilinearly correlated (r=0.679). Diseased leaves with 35% blast symptom can be predicted to have a 50% reduction of photosynthesis. The disease severity was linearly correlated (r=0.478) with total chlorophyll (chlorophyll a and chlorophyll b) per unit leaf area(TC). Light use efficiency was reduced by the fungal infection according to the light response curves. However, dark respiration (Rd) did not change after the fungal infection (p=0.526). Since the percent of reduction in photosynthesis greatly exceeded the percent of leaf area covered by blast lesions, loss of photosynthetic tissue on an area basis could not by itself account for the reduced photosynthesis. Quantitative photosynthetic reduction can be partially explained by decreasing TC, but cannot be explained by decreasing Rd. By photosynthesis (A)-internal CO$_2$ concentration (C$_i$ curve analysis, it was suggested that the fungal infection reduced ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activity, ribulose-1,5-bisphosphate (RuBP) regeneration, and inorganic phosphate regeneration. Thus, the reduction of photosynthesis by blast infection was associated with decreased TC and biochemical capacity, which comprises all carbon metabolism after CO$_2$ enters through the stomata.

• 한국안전학회지
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• 제30권1호
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• pp.94-103
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• 2015

This study analyzes the influence factors on elderly pedestrian accident. Elderly people are easy to be badly injured by car accidents compared to younger people. Therefore, various plans and measures are required to protect elderly pedestrian from accidents. However, pedestrian accidents studies only focused on microscopic factors such as attribute of driver, pedestrian, road design. In order to prevent pedestrian accident and reduce the severity of the accident, not only microscopic factors but macroscopic variables such as urban planning and facility should be considered. In this regard, this study develops an ordered probit model introduced the characteristics of urban facility which were not considered in the previous studies. The result shows that there is higher level of accident severity in such areas as large commercial area, well-developed area with transportation infrastructure service and non-pedestrian safety zone. Thus, various and appropriate countermeasures should be prepared in order that pedestrian accident can be prevented in the areas mentioned above. In addition to the aforementioned variables, it is revealed that other variables including vehicle speed, gender and age of pedestrian, weather condition, type of vehicle, etc. partly affect the severity of pedestrian accident.

• 한국농림기상학회지
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• 제10권1호
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• pp.17-24
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• 2008

지구온난화 문제는 국지적, 국내적 환경문제가 아닌 범지구적 차원에서 해결하여야 할 문제로 온실가스 규제와 지구환경의 조화를 위한 국제적 노력이 요구된다. 따라서 본 연구에서는 바이오매스 연소시 배출되는 비이산화탄소의 배출량을 정량적으로 추정하기 위한 방법론을 제시하고자 하였고, 산불피해지 구분은 물론 피해강도에 따라 배출되는 비이산화탄소 온실가스를 정량적으로 추정하기 위해 위성영상 자료를 활용하였으며, IPCC 기준인 Tier 2 수준으로 비이산화탄소 온실가스 배출량을 추정하였다. 본 연구에서는 2000년 4월에 발생한 우리나라 최대 산불인 삼척피해지를 대상으로 산불 전후 동일시기에 관측된 Landsat 위성영상으로부터 정규탄화지수(NBR)를 추출하여 산불피해지역과 피해강도를 정량적으로 분석하였다. 위성영상에서 추출된 피해면적과 피해강도별 분석자료는 바이오매스 연소로 인해 직접 배출되는 비이산화탄소 배출량 추정을 위한 활동자료로 활용하였다. 비이산화탄소 배출량 추정을 위해 IPCC의 추정식을 이용하였다. 산불피해강도별 연소효율은 피해강도가 '심'(burn severity: high)인 수관화 지역의 경우 0.43, 피해강도 '중'(burn severity: moderate) 0.40, 그리고 피해강도가 '경'인 지표화지(burn severity: low)의 경우는 0.15를 적용하였다. 바이오매스 연소시 배출되는 비이산화탄소 온실가스별 배출계수는 CO 130, $CH_4$ 9, $NO_x$ 0.7, $N_2O$ 0.11 값을 적용하였다. 삼척 산불피해지의 dNBR에 의한 피해강도 분석 결과, 전체 피해면적은 16,200ha로 나타났으며, 피해강도는 '경(Low: dNBR 152 이하)' 35%, '중(Moderate: dNBR 153-190)' 33%, '심(High: dNBR 191-255)' 32%의 면적분포를 보였다. 임상별 피해면적은 침엽수림 11,506ha(77%), 활엽수림 453ha(3%) 그리고 혼효림에서 2,978ha(20%)의 피해를 입은 것으로 평가되었다. 삼척 산불피해지의 바이오매스 연소로 인해 직접 배출된 비이산화탄소 배출량 추정 결과, CO 93%, CH4 6.4%, $NO_x$ 0.5%, $N_2O$ 0.1%의 순으로 배출량이 많았다. 삼척 산불피해지의 강도별 피해면적은 32%$\sim$35%의 분포로 고른 양상을 보이고 있지만 피해강도 '중' 지역에서 배출된 비이산화탄소의 양이 전체의 47%를 차지하여 배출율이 가장 높은 것으로 나타났다. 삼척산불 피해지의 총 비이산화탄소 온실가스 배출량은 CO 44.100Gg, CH4 3.053Gg, $NO_x$ 0.238Gg 그리고 $N_2O$는 0.038Gg이 배출된 것으로 추정되었다.

• Journal of Electrical Engineering and Technology
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• 제12권2호
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• pp.569-575
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• 2017

This paper proposes a method to utilize an energy storage system (ESS) based on the assessment of an area of severity (AOS) to voltage sag. The AOS is defined as a set of the fault positions that can cause voltage sags at many buses simultaneously. The assessment of AOS helps to determine an optimal location of ESS installation to minimize the expected sag frequency (ESF) at concerned buses. The ESS has the ability not only to play traditionally known roles but also to mitigate voltage sag impact on renewable energy sources (RES) in the islanded microgrid. Accordingly, using the proposed method the ESS has additional features to prevent the operation failure of RESs and improve the stability of the microgrid. In order to verify the presented method, a case study was conducted on the sample microgrid system that is modified from an IEEE 57-bus system.