• Nuclear Engineering and Technology
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• 제54권1호
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• pp.84-96
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• 2022

In the worst case, a temporary ignition source (also known as transient combustibles) between two electrical panels can damage both panels. Mitigation strategies for electrical panel fires were previously developed using fire modeling and risk analysis. However, since they do not comply with deterministic fire protection requirements, it is necessary to analyze the boundary values at which combustibles may damage targets depending on various factors. In the present study, a sensitivity analysis of input variables related to the damage threshold of two electrical panels was performed for dimensionless geometry using a Fire Dynamics Simulator (FDS). A new methodology using a damage evaluation map was developed to assess the damage of the electrical panel. The input variables were the distance between the electrical panels, the vertical height of the fuel, the size of the fire, the wind speed and the wind direction. The heat flux was determined to increase as the vertical distance between the fuel and the panel decreased, and the largest heat flux was predicted when the vertical separation distance divided by one half flame length was 0.3-0.5. As the distance between the panels increases, the heat flux decreases according to the power law, and damage can be avoided when the distance between the fuel and the panel is twice the length of the panel. When the wind direction is east and south, to avoid damage to the electrical panel the distance must be increased by 1.5 times compared to no wind. The present scale model can be applied to any configuration where combustibles are located between two electrical panels, and can provide useful guidance for the design of redundant electrical panels.

• Asian Pacific Journal of Cancer Prevention
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• 제15권12호
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• pp.4787-4793
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• 2014

Background: Many cancer patients experience poor pain control due to various factors, including misconceptions regarding the use of opioid analgesics. For management of cancer pain, interventions involving education of both patients and physicians have been attempted. Objectives: This review aimed to assess the current evidence of the benefits of education for the management of cancer pain. Methods: We searched the Medline, EMBASE, Cochrane library, and major Korean databases to identify relevant studies. We included most study designs, but excluded case series. The primary outcomes were pain intensity and quality of life (QoL). Two reviewers assessed the risk of bias using the Cochrane's tool for RCT and Risk of Bias Assessment tool for Non-randomized Studies (RoBANS) for non-randomized studies, independently. Results: After extensive searches, 3,324 publications were screened, and 32 studies were selected. The education interventions used in the included studies included a wide variety of education methods, but the most common method was a booklet produced for patients. Regardless of the education method used, the results of the meta-analysis were as follows. The SMDs of the most severe, average, and current pain in the RCTs were significant. The SMD of worst, average, and current pain were -0.34 (-0.55, -0.13), -0.40 (-0.64, -0.15), and -0.79 (-1.35, -0.23). In the non-randomized studies, the effects on average pain were significant, but those on worst and current pain were not. Conclusions: Education intervention reduced the pain of cancer patients. Therefore, patient education could be considered to be an effective method of cancer pain management. However, our data should be interpreted with caution, and studies using standardized protocols are needed to confirm these observations.

• 한국환경보건학회지
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• 제33권4호
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• pp.242-249
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• 2007

Indoor air quality has become a topic of interest and concern. Especially changes in construction design and the increased use of synthetic products may result in an increasing of complaints and health effects about the quality of indoor air at home. In this study, nitrogen dioxide($NO_2$) and volatile organic compounds(VOCs) within new and established apartments on the basis of 4 years of building year were measured every 3 days consecutively during 60 days. We selected each 10 house in Seoul, Asan and Daegu, respectively, and produced risk numbers for hazard quotients, and predicted increases in incidence of cancer. The calculations were made for the adult with default exposure values and also made for a worst case scenario using Monte-Carlo simulation as describing the reasonable exposure(RME). Mean of Monte carlo analysis by benzene, in the construction under 4 years (male: $9.2{\times}10^{-5}$, female: $1.0{\times}10^{-4}$) and over 4 years (male: $6.8{\times}10^{-5}$, female: $8.3{\times}10^{-5}$) exceeded $10^{-6}$ of permitted standards in US EPA, RME of Monte carlo analysis. In construction under 4 yews (male: $9.9{\times}10^{-3}$, female: $9.6{\times}10^{-3}$) and over 4 years (male: $9.8{\times}10^{-3}$, female: $7.8{\times}10^{-3}$) exceeded $10^{-4}$ of maximum permitted standards in US EPA. The hazard index of non-carcinogenic pollutants by nitrogen dioxide, toluene, m,p-xylene and o-xylene, both male and female in apartment constructed under 4 yews and over 4 years was found less than the permitted standards of hazardous health effects in CTE. Significant cancer risks and non-cancer hazard quotients were predicted in under 4 yews of building year.

• 한국수소및신에너지학회논문집
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• 제23권6호
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• pp.588-597
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• 2012

In the present study, the dispersion characteristics of hydrogen leakage from a Fuel Cell Vehicle (FCV) were analyzed by numerical simulation in order to assess the risk of a hydrogen leakage incident in a long road tunnel. In order to implement the worst case of hydrogen leakage, the FCV was located at the center of a tunnel, and hydrogen was completely discharged within 63 seconds. The Leakage velocity of hydrogen was adopted sub-sonic speed because that the assumption of the blockage effect of secondary device inside a vehicle. The temporal and spatial evaluation of the hydrogen concentration as well as the flammable region in a road tunnel was reported according to change of ventilation operating conditions. The hydrogen was blended by supply air form a ventilation fan, however, the hydrogen was discharged to outside in the exhaust air. It is observed that the efficiency way to eliminate of hydrogen is supply air operating condition under the hazardous hydrogen leaking incident. The present numerical analysis can be provided useful information of ventilation under the hydrogen leaking situation.

• 전기전자학회논문지
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• 제15권3호
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• pp.218-226
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• 2011

본 논문은 현재 유선방송 기술기준에서 CDMA 이동통신서비스 대역의 누설전자파 기준이 적절한지를 검증하고자 하였다. 먼저, CDMA 2000 1X 기지국 장비를 통한 실험결과로부터 CDMA 이동통신 시스템의 최대 허용 간섭 레벨은 -110dBm/1.23MHz인 것으로 분석되었다. 이를 토대로 이동통신기지국에 거의 영향을 주지 않을 케이블 방송 옥외 전송설비의 누설 간섭전력의 임계레벨과 누설전자파 세기를 산출하였다. 일반적으로 옥외에서 측정되는 외부시스템의 배경 간섭레벨인 -100~-80dBm/1.23MHz에 대해서 허용될 수 있는 케이블 방송 설비의 누설전자파 임계치는 현행 유선방송 기술기준을 만족시키지 못하였다. 이것은 현행 기술기준이 지나치게 최악의 경우를 상정하여 설정되었음을 의미하므로 이동통신사업자의 실제적인 기지국 조건을 적용하여 합리적인 기술기준을 마련하여야 할 것이다.

• 한국정보과학회논문지:시스템및이론
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• 제29권9호
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• pp.520-529
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• 2002

본 논문은 분산 실시간 시스템에서 실시간 동적 알고리즘으로 메시지를 스케줄링하기 위한 개선된 접근법을 제안한다. EDF(Earliest Deadline First) 스케줄링 정책에서 메시지의 중간 종료시한을 계산하기 위한 방법을 제시하고, 이는 우선순위 할당을 위해 사용하는 슬랙값을 조정하는데 사용된다 수정된 슬랙값으로 메시지의 우선순위값은 보다 정확하게 결정될 수 있으며, 결과적으로 메시지의 스케줄가능성 효율을 증가시킬 수 있다. 개선된 EDF 스케줄링 정책을 적용함으로써, 전송 메시지의 최악의 응답시간을 줄일 수 있었고, 메시지 전송의 실시간적 보장성 문제를 개선하였다. 또한, 개선된 EDF 스케줄링 정책을 기반으로 전송되는 메시지 집합에 대한 스케줄 가능성을 검사하기 위해 간단한 분석 방법을 제공하고 시뮬레이션을 통해 이전의 DM(Deadline Monotonic)과 기존의 EDF을 적용한 예와 비교함으로써, 본 연구 결과의 효율성을 보였다.

• 한국통신학회논문지
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• 제29권2A호
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• pp.181-186
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• 2004

2003년 세계전파통신회의(WRC-2003)에서 지상망과 고밀도 고정위성업무(HDFSS:High-Density fixed satellite service)의 주파수 공유 및 HDFSS용 하향링크 후보대역 선정문제로 이슈화된 40 ㎓ 대역에서 정지위성망과 지상망간 주파수 공유에 따른 간섭 영향을 우리나라에서 운용하는 것으로 설정해 분석하였다. 40 ㎓ 대역 정지위성망과 지상망의 전형적인 특성 파라미터를 이용하여 시뮬레이션한 결과, 우리나라 지상 고정업무 무선국의 안테나가 같은 40 ㎓ 대역을 공유하는 정지위성을 향할 경우, 40 ㎓ 지상망의 운용특성들이 맞물려. 간섭을 받을 수 있는 최악의 특정 조건이 이루어질 수 있음을 보았다. 이러한 상황은 고층건물이 밀집된 지역에 지상망을 설치할 때 발생할 수 있으므로. 향후 40 ㎓ 대역의 고밀도 지상고정업무(HDFS :High-Density fixed service) 무선국들이 설치될 때, 정지궤도 지향을 피하는 간섭경감기법이 강구되어야 할 것으로 보인다.

• 한국항공우주학회지
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• 제32권7호
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• pp.126-132
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• 2004

위성 추진제 탱크의 열제어는 써모스탯에 의해 작동되는 히터를 이용해 수행된다. 적절한 위치에 써모스탯을 부착하는 것이 관건이지만 구형 탱크에서는 부착위치를 수치적으로 정확하게 부여하는 것이 불가능하다. 실제로는 도면에 대략적으로 위치를 제시한 후 작업자의 경험과 판단에 의존하여 써모스탯을 부착하는 것이 현실이다. 그러므로 써모스탯의 부착위치에 대한 민감도 해석을 수행함으로써 그에 따른 탱크의 열적 거동 및 열제어에 미치는 영향을 정량적으로 파악하였다. 실제 탱크 모듈 조립시 써모스탯의 부착위치에 대한 오차가 존재하더라도 설계 도면에 명시된 값보다 크게 벗어나지 않는 한 탱크의 열제어 성능은 충분히 보장되리라 판단된다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.654-655
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• 2003

Korea has experienced 10 a Cochlodinium polykrikoides red tide outbreaks during the last 10 years (1993-2002). The monitoring activities at National Fisheries Research and Development Institute (NFRDI) in Korea have been extended to all the coastal waters after the worst of fish killing by C. polykrikoides blooms in 1995. NFRDI is looking forward to finding out the feasibility of red tide detection around Korean waters using satellite remote sensing of NOAA/AVHRR, Orbview-2/SeaWiFS, IRS-P4/OCM and Terra/MODIS on real time base. In this study, we used several alternative methods including climatological analysis, spectral and optical methods which may offer a potential detection of the major species of red tide in Korean waters. The relationship between the distribution of SST and C. polykrikoides bloom areas was studied. In climatological analysis, NOAA, SeaWiFS, OCM satellite data in 20th and 26th August 2001 were chosen using the known C. polykrikoides red tide bloom area mapped by helicopter reconnaissance and ground observation. The 26th August, 2001 SeaWiFS chlorophyll a anomaly imageries against the imageries of non-occurring red tide for August 20, 2001 showed the areas C. polykrikoides occurred. The anomalies of chlorophyll a concentration from satellite data between before and after red tide outbreaks showed the similar distribution of C. polykrikoides red tide in 26th August, 2001. The distribution of the difference in SST between daytime and nighttime also showed the possibility of red tide detection. We used corrected vegetation index (CVI) to detect floating vegetation and submerged vegetation containing algal blooms. The simple result of optical absorption from C. polykrikoides showed that if we use the optical characteristics of each red tide we will be able to get the feasibility of the red tide detection.

• 한국가스학회지
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• 제26권3호
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• pp.10-20
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• 2022

지난 10년간 국내 화학물질 사고의 약 21%가 운송 차량에 의해 발생하였으며 그중 암모니아는 국내 화학물질 관련 사고 672건 중 82건으로 가장 많은 사고가 발생한 화학물질이다. 따라서 본 연구에서는 어선과 운송 차량 간 암모니아 이적 작업 중 누출사고가 발생할 경우의 계절별 대안 시나리오와 최악의 시나리오를 가정하였고 인구밀도 자료와 기상 특성을 토대로 ALOHA와 프로빗 분석, Python의 Folium 모듈을 통해 피해 범위와 그 영향을 해석하였다. 대안 시나리오에서 복사열의 경우 겨울철 2도 화상이 우려되는 범위가 41m, 최고 복사열이 5.01kW/m²로 가장 높았으며 과압의 경우 피해 최저기준보다 낮은 6.56kPa를 보여 압력에 의한 영향이 적은 것을 파악하였다. 그리고 독성 피해의 경우 여름철 EPPG-2 끝점이 5.0km로 복사열과 과압의 피해 영향보다 넓은 범위를 보였고, 독성 사망률에 대한 프로빗 분석 결과 인구밀도가 높은 항만과 관광지역에서 95~100%의 사망률을 확인하였다.