• 한국전자통신학회논문지
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• 제10권10호
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• pp.1079-1086
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• 2015

본 논문은 안전 무결성 레벨이 4(: Safety Integrity Level 4)인 안전 관련 시스템에 적합한 출력 모듈의 구조를 설계하였고, 설계된 출력 모듈에 요구되는 정량적 목표치의 수준을 제시하였다. 특히 다양한 출력 방식 중에서 릴레이 출력 신호와 아날로그 신호로 구성된 출력 모듈이 안전 기능을 수행하는 시스템의 구성 요소인 경우를 적용하였다. 분석 방법은 FMEA(: Failure Modes and Effect Analysis), FTA(: Fault Tree Analysis) 방식을 이용하였다. 그 결과로 철도 응용 규격인 IEC 62425의 요구사항을 준수하는 SIL4 안전 관련 시스템의 출력 모듈의 구조와 고장빈도인 정량적 목표치를 제시하였다.

• 한국가스학회지
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• 제6권1호
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• pp.66-73
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• 2002

본 연구에서는 결함수목 분석법을 이용하여 Safety Integrity Level(SIL)을 평가하고 시스템의 목표한 SIL에 도달하지 못할 경우에 신뢰도 분석과 시스템 retrofit을 통해서 목표한 SIL을 만족시키게 하는 방법을 개발하였다. 신뢰도 분석에 근거한 SIL 평가 방법을 검증하기 위해서 415V Diesel BUS에 대해서 위험성 분석을 수행하였다. 기존의 415V Diesel BUS에 대한 이용가능 상태는 $99.40\%$로 SIL 2등급에 해당된다. 개발된 평가방법을 이용하여 diesel generator와 isolator switch의 교체후 시스템의 이용가능 상태는 $99.94\%$ SIL 3등급으로 상승되었다. 본 연구에서 제시한 신뢰도에 근거한 SIL 평가 방법을 적용하면 사고 예방과 손실감소로 일어나는 유지보수 비용의 절감 등을 가져오면 물론 시스템의 신뢰도를 극대화 할 수 있다.

• 정보보호학회논문지
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• 제22권1호
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• pp.107-115
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• 2012

우리나라의 정보화 수준과 비교하여 정보보호 수준은 상대적으로 낮다. 정보보호 예산 수준 역시 전체 정보화 예산대비 5%대로 미미하며 기업들의 사후대응 중심의 정보보호 조치는 반복적인 피해비용을 야기한다. 정보보호 침해사고에 대한 대응은 사후대응 체계에서 예방과 사전탐지 중심으로 바뀌어야한다. 정보사회에서의 침해사고 대응은 개인의 책임보다는 국가와 기업이 공동으로 대처해야할 영역이라는 인식 전환이 필요하다. 2004년 정보보호조치 및 안전진단 관련 지침이 고시되면서 우리나라도 침해사고 예방을 위한 제도적 기반을 마련하였다. 하지만 제도적으로 시행되고 있는 관리적, 기술적, 물리적 보호조치가 실제 침해사고 대응에 완벽한 예방책이 되지는 못한다. 본 연구에서는 현행 제도적 보호조치의 예방 효과에 대해 살펴보고 제도적 한계와 개선점을 도출하여 기업들이 실질적인 목표 보안수준을 유지하기 위해 필요한 효과적인 침해 예방 대응책으로써의 선행위협 관리 모델을 제안한다.

• Safety and Health at Work
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• 제3권3호
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• pp.224-234
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• 2012

Objectives: This study was conducted in order to obtain information concerning the health hazards that may result from a 13 week inhalation exposure of n-pentane in Sprague-Dawley rats. Methods: This study was conducted in accordance with the Organization for Economic Co-operation and Development (OECD) guidelines for the testing of chemicals No. 413 'Subchronic inhalation toxicity: 90-day study (as revised in 2009)'. The rats were divided into 4 groups (10 male and 10 female rats in each group), and were exposed to 0, 340, 1,530, and 6,885 ppm n-pentane in each exposure chamber for 6 hour/day, 5 days/week, for 13 weeks. All of the rats were sacrificed at the end of the treatment period. During the test period, clinical signs, mortality, body weights, food consumption, ophthalmoscopy, locomotion activity, urinalysis, hematology, serum biochemistry, gross findings, organ weights, and histopathology were assessed. Results: During the period of testing, there were no treatment related effects on the clinical findings, body weight, food consumption, ophthalmoscopy, urinalysis, hematology, serum biochemistry, gross findings, relative organ weight, and histopathological findings. Conclusion: The no-observable-adverse-effect level (NOAEL) of n-pentane is evaluated as being more than 6,885 ppm (20.3 mg/L) in both male and female rats. n-pentane was not a classified specific target organ toxicity in the globally harmonized classification system (GHS).

• 대한약침학회지
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• 제19권3호
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• pp.213-224
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• 2016

Objectives: Ginseng Rh2+ is enzyme-treated ginseng extract containing high amounts of converted ginsenosides, such as compound k, Rh2, Rg3, which have potent anticancer activity. We conducted general and genetic toxicity tests to evaluate the safety of ginseng Rh2+. Methods: An acute oral toxicity test was performed at a high-level dose of 4,000 mg/kg/day in Sprague-Dawley (SD) rats. A 14-day range-finding study was also conducted to set dose levels for the 90-day study. A subchronic 90-day toxicity study was performed at dose levels of 1,000 and 2,000 mg/kg/day to investigate the no-observed-adverse-effect level (NOAEL) of ginseng Rh2+ and target organs. To identify the mutagenic potential of ginseng Rh2+, we conducted a bacterial reverse mutation test (Ames test) using amino-acid-requiring strains of Salmonella typhimurium and Escherichia coli (E. coli), a chromosome aberration test with Chinese hamster lung (CHL) cells, and an in vivo micronucleus test using ICR mice bone marrow as recommended by the Korean Ministry of Food and Drug Safety. Results: According to the results of the acute oral toxicity study, the approximate lethal dose (ALD) of ginseng Rh2+ was estimated to be higher than 4,000 mg/kg. For the 90-day study, no toxicological effect of ginseng Rh2+ was observed in body-weight changes, food consumption, clinical signs, organ weights, histopathology, ophthalmology, and clinical pathology. The NOAEL of ginseng Rh2+ was established to be 2,000 mg/kg/day, and no target organ was found in this test. In addition, no evidence of mutagenicity was found either on the in vitro genotoxicity tests, including the Ames test and the chromosome aberration test, or on the in vivo in mice bone marrow micronucleus test. Conclusion: On the basis of our findings, ginseng Rh2+ is a non-toxic material with no genotoxicity. We expect that ginseng Rh2+ may be used as a novel adjuvant anticancer agent that is safe for long-term administration.

• 한국안전학회지
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• 제35권1호
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• pp.107-115
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• 2020

This paper introduces the first vital area identification (VAI) process for the physical protection of nuclear power plants (NPPs) during low power and shutdown (LPSD) operation. This LPSD VAI is based on the 3rd generation VAI method which very efficiently utilizes probabilistic safety assessment (PSA) event trees (ETs). This LPSD VAI process was implemented to the virtual NPP during LPSD operation in this study. Korea Atomic Energy Research Institute (KAERI) had developed the 2nd generation full power VAI method that utilizes whole internal and external (fire and flooding) PSA results of NPPs during full power operation. In order to minimize the huge burden of the 2nd generation full power VAI method, the 3rd generation full power VAI method was developed, which utilizes ETs and minimal PSA fault trees instead of using the whole PSA fault tree. In the 3rd generation full power VAI method, (1) PSA ETs are analyzed, (2) minimal mitigation systems for avoiding core damage are selected from ETs by calculating system-level target sets and prevention sets, (3) relatively small sabotage fault tree that has the systems in the shortest system-level prevention set is composed, (4) room-level target sets and prevention sets are calculated from this small sabotage fault tree, and (5) the rooms in the shortest prevention set are defined as vital areas that should be protected. Currently, the 3rd generation full power VAI method is being employed for the VAI of Korean NPPs. This study is the first development and application of the 3rd generation VAI method to the LPSD VAI of NPP. For the LPSD VAI, (1) many LPSD ETs are classified into a few representative LPSD ETs based on the functional similarity of accident scenarios, (2) a few representative LPSD ETs are simplified with some VAI rules, and then (3) the 3rd generation VAI is performed as mentioned in the previous paragraph. It is well known that the shortest room-level prevention sets that are calculated by the 2nd and 3rd generation VAI methods are identical.

• 한국산업보건학회지
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• 제21권2호
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• pp.73-81
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• 2011

The purpose of this study was to obtain scientific information regarding classification and health hazards that may result from a 13 weeks inhalation exposure of isoprene in Sprague-Dawley (SD) rats. The testing method was conducted in accordance with OECD guidelines for the testing of chemicals No. 413. The Rats were divided into 4 groups (10 male and 10 female rats in each group) and exposed to 0, 360, 1,620, 7,300 ppm isoprene in each exposure chamber for 6 h/day, 5 days/week, for 13 weeks. As a result, there were no mortality or abnormality during the period of study and did not show any significant changes of body weight. There were no dose response changes in urinalysis, hematological and serum biochemical value examination. Relative organ weight was increased significantly the right kidney in 7,300 ppm group of male rats. In female rats, relative organ weight of the left kidney and the both lungs in 1,620 ppm group and the left lung and the both kidneys in 7,300 ppm group were increased significantly. But the histopathological findings did not reveal any exposure-related changes. According to the above results, the no observable adverse effect level (NOAEL) of isoprene was 7,300 ppm (20.3 mg/L) in both male and female rats. In conclusion, Isoprene was not classified specific target organ toxicity of the 'Standard for Classification and Labeling of Chemical Substance and Material Safety Data Sheet' (Ministry of Employment and Labor, 2009).

• 한국안전학회지
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• 제6권3호
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• pp.56-63
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• 1991

본 연구는 가설부재의 신뢰성 설계규준을 고찰하고, Ellingwood가 제안한 신뢰성 해석과 신뢰성 설계규준 산정 알고리즘으로 부터 실용적인 알고리즘을 유도하였다. 하중의 불확실량은 우리의 실정을 고려한 적절한 값을 택하여 신뢰성 해석 및 신뢰성 설계규준을 산정했다. 현행 WSD와 USD 설계법의 신뢰성 수준을 분석함으로써, 우리 실정에 적당한 목표신뢰성지수 $\beta$$_{o}$ =3.5를 택하여 LRFD설계규준에 의한 하중-저항계수를 제안했으며, 신뢰성 설계와 비슷한 신뢰성을 갖는 WSD의 강재의 허용응력을 산정제안했다. 본 연구에서 제안한 신뢰성 설계규준 및 허용응력은 일정한 신뢰성을 주는 보다 합리적인 설계가 됨을 알 수 있었다.

• Toxicological Research
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• 제8권2호
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• pp.171-177
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• 1992

To investigate a short term screening method for carcinogenic quinone compounds, 8-hydroxydeoxyguanosine (8-OHdG), an oxidative DNA damage, was determined in the kidney and liver DNA isolated from Sprague-Dawley rats after i.p.injection of 7 mg/kg adriamycin (AM), 7mg/kg tetrahydropyranyladriamycin (THP), and 10mg/kg daunomycin (DM) by HPLC-electrochemical detector system. 8-OHdG was also determined from rat hepatocvtes and calf thymus DNA exposed to AM, DM and THP. When rats were treated with DM and THP, 8-OHdG was significantly increased in the kidney compared to control group, and remained at high level (7.9~9.0, 8-OHdG/dG${\times}10^4$)at the end of experiments (48hr after treatment). 8-OHdG level in cultured hepatocyte exposed to AM, DM and THP was 1.5~2 fold higher than control at all time points. (1,2,3,4hr after treatment). From calf thymus DNA exposed to AM, DM and THP, 8-OHdG was 2.5 fold higher than of control. These results suggest that quantitation of 8-OHdG may provide a useful marker for identifying target organ in oxidative chemical carcinogenesis and for short term screening of free radical generating carcinogens.

• 한국환경과학회지
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• 제29권9호
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• pp.871-883
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• 2020

Due to recent heavy rain events, there are increasing demands for adapting infrastructure design, including drainage facilities in urban basins. Therefore, a clear definition of urban rainfall must be provided; however, currently, such a definition is unavailable. In this study, urban rainfall is defined as a rainfall event that has the potential to cause water-related disasters such as floods and landslides in urban areas. Moreover, based on design rainfall, these disasters are defined as those that causes excess design flooding due to certain rainfall events. These heavy rain scenarios require that the design of various urban rainfall facilities consider design rainfall in the target years of their life cycle, for disaster prevention. The average frequency of heavy rain in each region, inland and coastal areas, was analyzed through a frequency analysis of the highest annual rainfall in the past year. The potential change in future rainfall intensity changes the service level of the infrastructure related to hand-to-hand construction; therefore, the target year and design rainfall considering the climate change premium were presented. Finally, the change in dimensional safety according to the RCP8.5 climate change scenario was predicted.