• 전기학회논문지
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• 제63권8호
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• pp.1152-1158
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• 2014

In Modern society, various important systems is operated such as nuclear plant, chemistry industry, railway system and so on. But these systems can cause high risky accidents. Hence, these systems are required to ensure the individual and societal risk criteria. In this paper, we reviewed EU risk criteria which is already operated in UK and Netherlands, then we proposed acceptable risk criteria and estimated risk of oil immersed transformer for subway with FN curve.

• 한국화재소방학회논문지
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• 제22권5호
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• pp.35-42
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• 2008

최근 KDX-III, LPX 등 대형함 건조사업의 진행으로 예전과 달리 함정 규모가 커지고 함정 내 승조원수 및 승조 인원 구성도 다양화 되고 있는 상황을 반영하여 화재로 인한 해군함정의 위험도를 정량적으로 평가 분석하였다. 이를 위해 해군 함정의 복잡한 화재 전파양상을 사건수목분석(ETA)기법으로 모델링하였고, 승조원 침실 내 화재해석을 위해 CFAST 프로그램을 이용하여 화재 전파양상 및 화재구역 내거주가능시간(임계시간)을 예측하였다. 이를 승조원 탈출 시간과 비교하여 상황별 사망자 수를 산출하였으며 FN-curve로 전반적인 위험도를 도식하여 화재 위험도의 수용여부를 판단할 수 있는 방법을 제시하였다. 본 연구에서 제시된 방법론을 바탕으로 새롭게 건조되는 함정 설계단계에서 화재 발생시 함정에서의 인명위험성을 적절하게 평가할 수 있는 도구로 활용이 가능할 것으로 사료된다.

• 응용통계연구
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• 제34권2호
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• pp.225-238
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• 2021

이진분류모형의 성능을 탐색하는 시각적인 대표적인 방법인 ROC 곡선과 TOC 곡선 그리고 TROC 곡선은 혼동행렬을 구성하는 TP, TN, FP, FN 그리고 이들의 비율인 TPR, TNR, FPR, FNR으로 구현된다. 본 연구에서는 두 종류의 비율비인 오즈를 고려하여 단위면적인 정사각형에서의 구현하는 오즈 곡선을 제안하고, ROC 곡선과의 관계를 보인다. 오즈 곡선에서 판별력을 측정하는 두 종류의 측도를 제안하고, 오즈 곡선들의 형태를 바탕으로 두 종류의 측도를 이용하여 두 분류 분포의 판단 기준을 설정한다. 본 연구에서 제안한 오즈 곡선은 다른 시각적인 방법 등과 같이 유용하게 사용할 수 있으며, 오즈 곡선의 판별력을 측정하는 두 종류의 측도들은 분류 성능을 판단하는 대안적인 방법으로 같이 이용할 수 있다.

• 해양환경안전학회지
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• 제22권3호
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• pp.259-267
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• 2016

The study performs a risk analysis on container ship accidents using accident data collected over the six years from 2006 to 2011, presents the resulting risk level, and suggests three risk mitigation measures to reduce the overall risk, for the safer operation of container ships. More specifically, starting from the initial accident of collision, we developed 13 different accident scenarios using event tree analysis based on which the overall risk level was obtained and presented as a FN curve. Since diverse human factors are the main cause of most of the ship accidents, our study focuses on the effect of reducing human causes on the resulting risk level. For the research we considered the injuries for the calculation of fatality with the help of MAIS. The results show that collision was the main type of accident, accounting for 62 % of all accidents, and the measures employed were proven to be effective in the sense that the risk level was much lowered and the average number of fatalities was also reduced. With more data accumulated, more precise risk level will be calculated with which the practical risk mitigating measures will be also developed. For future study, economic loss and environmental damage as consequences need to be considered.

• 전자공학회논문지
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• 제53권7호
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• pp.49-55
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• 2016

디지털 포렌식 영상은 여러 가지 영상타입으로 위 변조되어 유통되는 심각한 문제가 대두되어 있다. 이러한 문제를 해결하기 위하여, 본 논문에서는 포렌식 영상의 분류 알고리즘을 제안한다. 제안된 알고리즘은 여러 가지 영상타입의 그레이 레벨 co-occurrence 행렬의 특성 중에서 콘트라스트와 에너지 그리고 영상의 엔트로피로 21-dim.의 특징벡터를 추출하고, 결정나무 플랜에서 분류학습을 위하여 PPCA를 이용하여 2-dim.으로 차원을 축소한다. 포렌식 영상의 분류 테스트는 영상 타입들의 전수조합에서 수행되었다. 실험을 통하여, TP (True Positive)와 FN (False Negative)을 검출하고, 제안된 알고리즘의 성능평가에서 민감도 (Sensitivity)와 1-특이도 (1-Specificity)의 AUROC (Area Under Receiver Operating Characteristic) 커브 면적은 0.9980으로 'Excellent(A)' 등급임을 확인하였다. 산출된 최소평균 판정에러 0.0179에서 분류할 포렌식 영상타입이 모두 포함되어 분류 효율성이 높다.

• 전자공학회논문지
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• 제51권3호
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• pp.75-81
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• 2014

디지털 영상의 배포에서, 저작권 침해자에 의해 영상이 불법으로 위 변조되어 유통되는 심각한 문제가 대두되어 있다. 이러한 문제를 해결하기 위하여, 본 논문에서는 위 변조된 디지털 영상의 에지 에너지 정보를 이용한 영상 포렌식 판정 알고리즘을 제안한다. 제안된 알고리즘은 SA (Streaking Artifacts)와 SPAM (Subtractive Pixel Adjacency Matrix)을 이용하여, 원 영상의 JPEG 압축률 (QF=90, 70, 50, 30)에 따른 에지정보와 질의영상의 에지정보를 추출하고, 이를 각각 비교하여 위 변조 여부를 판정한다. 원 영상과 질의영상의 에지정보 매칭은 JPEG 압축률 조합의 임계치 (TCJCR : Threshold by Combination of JPEG Compression Ratios)에 따라 이루어진다. 실험을 통하여, TP (True Positive)와 FN (False Negative)은 87.2%와 13.8%이며, 산출된 최소평균 판정 에러는 0.1349이다. 그리고 제안된 알고리즘의 성능평가에서 민감도 (Sensitivity)와 1-특이도(1-Specificity)의 AUROC (Area Under Receiver Operating Characteristic) 커브 면적은 0.9388로 'Excellent(A)' 등급임을 확인하였다.

• 한국안전학회지
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• 제32권5호
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• pp.157-167
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• 2017

Millions of People die every year from diseases caused by exposure to outdoor air pollution. Especially, one of the most severe types of air pollution is fine particulate matter (PM10, PM2.5). South Korea also has been suffered from severe PM. This paper analyzes regional risks induced by PM10 and PM2.5 that have affected domestic area of Korea during 2014~2016.3Q. We investigated daily maxima of PM10 and PM2.5 data observed on 284 stations in South Korea, and found extremely high outlier. We employed extreme value distributions to fit the PM10 and PM2.5 data, but a single distribution did not fit the data well. For theses reasons, we implemented extreme mixture models such as the generalized Pareto distribution(GPD) with the normal, the gamma, the Weibull and the log-normal, respectively. Next, we divided the whole area into 16 regions and analyzed characteristics of PM risks by developing the FN-curves. Finally, we estimated 1-month, 1-quater, half year, 1-year and 3-years period return levels, respectively. The severity rankings of PM10 and PM2.5 concentration turned out to be different from region to region. The capital area revealed the worst PM risk in all seasons. The reason for high PM risk even in the yellow dust free season (Jun. ~ Sep.) can be inferred from the concentration of factories in this area. Gwangju showed the highest return level of PM2.5, even if the return level of PM10 was relatively low. This phenomenon implies that we should investigate chemical mechanisms for making PM2.5 in the vicinity of Gwangju area. On the other hand, Gyeongbuk and Ulsan exposed relatively high PM10 risk and low PM2.5 risk. This indicates that the management policy of PM risk in the west side should be different from that in the east side. The results of this research may provide insights for managing regional risks induced by PM10 and PM2.5 in South Korea.

• Archives of Pharmacal Research
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• 제19권6호
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• pp.566-569
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• 1996

A sensitivity method has been developed for the detection and determination of niflmic acid(NA) in human urine. Samples were extracted with diethylether. Flunixin (FN) was added to the sample prior to extraction as an internal standard. Niflumic acid was converted to its methyl derivative and analyzed by capillary gas chromatography/negative chemical isonization mass spectrometry. Using selected ion monitoring (SIM), the levels of NA down to 5 pg/ml could be detected in 5 ml spiked urine sample. Calibration curve was linear over the range of 0.5 ppm-50 ppm. The recovery of niflumic acid from urine at 40 pg/ml was to be $91.7{\pm}3.8(n=3)$ and the coefficient of variation was 4.1%.

• 동력기계공학회지
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• 제14권2호
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• pp.71-77
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• 2010

This paper was studied on microstructure, mechanical properties and corrosion characteristics of 316L stainless steel pipe welds was fabricated by orbital welding process. S-Ar specimen was fabricated by using Ar purge gas and S-$N_2$ specimen was fabricated by using $N_2$ purge gas. Ferrite was not detected in weld metal of S-$N_2$ specimen but the order of 0.13 Ferrite number(FN) was detected in weld metal of S-Ar specimen. Oxygen and Nitrogen concentration of S-$N_2$ specimen was higher than S-Ar specimen on HAZ and inner bead. The welds microstructural characteristics of S-Ar and S-$N_2$ specimens are similar. The microvickers hardness values of S-Ar and S-$N_2$ specimens welds were similar and average values of each regions were in the range of 174~194. The microstructures of S-Ar and S-$N_2$ weld metal were full austenite by primary austenite solidification. The Solidification structures of S-Ar and S-$N_2$ weld metal were formed directional dendrite toward bead center. The potentiodynamic polarization curve of STS 316L pipe welds exhibited typical active, passive, transpassive behaviour. Corrosion current density$(I_{corr.})$ and corrosion rate values of S-Ar specimen in 0.1M HCl solution were $0.95{\mu}A/cm^2$ and $0.31{\mu}A$/year respectively. The values of S-$N_2$ specimen were $1.4{\mu}A/cm^2$ and $0.45{\mu}m$/year.

• 대한안전경영과학회지
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• 제20권1호
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• pp.1-9
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• 2018

As the chemical industry becomes more advanced, the awareness of chemical accidents is rising, and legal systems for chemical safety management are strengthened. In this study, quantitative risk assessment of liquid chlorine leak was conducted. Risk assessment was performed in the order of frequency analysis, consequence analysis, and risk calculation. The individual risk was presented in the form of contour lines. The social risk was expressed by the FN curve. The risk of day and night was in an unacceptable area, so it was required to mitigate risk. Therefore in-building, which could trap the pool, was selected as a risk mitigation measure. As a result of the cost benefit analysis, it was concluded that this measure should be reasonably implemented.