• Nuclear Engineering and Technology
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• 제46권6호
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• pp.803-816
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• 2014

Defense-in-depth is a fundamental safety principle for the design and operation of nuclear power plants. Despite its general appeal, defense-in-depth is not without its drawbacks, which include its potential for concealing the occurrence of hazardous states in a system, and more generally rendering the latter more opaque for its operators and managers, thus resulting in safety blind spots. This in turn translates into a shrinking of the time window available for operators to identify an unfolding hazardous condition or situation and intervene to abate it. To prevent this drawback from materializing, we propose in this work a novel safety principle termed "observability-in-depth". We characterize it as the set of provisions technical, operational, and organizational designed to enable the monitoring and identification of emerging hazardous conditions and accident pathogens in real-time and over different time-scales. Observability-in-depth also requires the monitoring of conditions of all safety barriers that implement defense-in-depth; and in so doing it supports sensemaking of identified hazardous conditions, and the understanding of potential accident sequences that might follow (how they can propagate). Observability-in-depth is thus an information-centric principle, and its importance in accident prevention is in the value of the information it provides and actions or safety interventions it spurs. We examine several "event reports" from the U.S. Nuclear Regulatory Commission database, which illustrate specific instances of violation of the observability-in-depth safety principle and the consequences that followed (e.g., unmonitored releases and loss of containments). We also revisit the Three Mile Island accident in light of the proposed principle, and identify causes and consequences of the lack of observability-in-depth related to this accident sequence. We illustrate both the benefits of adopting the observability-in-depth safety principle and the adverse consequences when this principle is violated or not implemented. This work constitutes a first step in the development of the observability-in-depth safety principle, and we hope this effort invites other researchers and safety professionals to further explore and develop this principle and its implementation.

• Safety and Health at Work
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• 제15권1호
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• pp.24-32
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• 2024

Background: Learning from incidents for accident prevention is a two-stage process, involving the investigation of past accidents to identify the causal factors, followed by the identification and implementation of remedial measures to address the identified causal factors. The focus of past research has been on the identification of causal factors, with limited focus on the identification and implementation of remedial measures. This research begins to contribute to this gap. The motivation for the research is twofold. First, previous analyses show the recurring nature of accidents within the Ghanaian mining industry, and the causal factors also remain the same. This raises questions on the nature and effectiveness of remedial measures identified to address the causes of past accidents. Secondly, without identifying and implementing remedial measures, the full benefits of accident investigations will not be achieved. Hence, this study aims to assess the nature of remedial measures proposed to address investigation causal factors. Method: The study adopted SMARTER from business studies with the addition of HMW (H - Hierarchical, M - Mapping, and W - Weighting of causal factors) to analyse the recommendations from 500 individual investigation reports across seven different mines in Ghana. Results: The individual and the work environment (79%) were mostly the focused during the search for causes, with limited focus on organisational factors (21%). Forty eight percentage of the recommendations were administrative, focussing on fixing the problem in the immediate affected area or department of the victim(s). Most recommendations (70.4%) were support activities that only enhance the effectiveness of control but do not prevent/mitigate the failure directly. Across all the mines, there was no focus on evaluating the performance of remedial measures after their implementation. Conclusion: Identifying sharp-end causes leads to proposing weak recommendations which fail to address latent organisational conditions. The study proposed a guide for effective planning and implementation of remedial actions.

• 한국심리학회지:학교
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• 제18권3호
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• pp.317-349
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• 2021

본 연구에서는 디지털 미디어 과사용 여부를 측정하는 인터넷(IOS-Q), 게임(GOS-Q), 스마트폰(SOS-Q) 과사용 선별 질문지를 대규모 일반 청소년 집단을 대상으로 타당화하여, 선별검사 장면에서 활용할 수 있는 유용한 검사 도구를 제시하고자 하였다. 이를 위해 총 9,336명의 중학생(남 4,796명, 여 4,540명)을 두 개 집단으로 구분하고 확인적 요인분석과 탐색적 요인분석을 각각 실시하였으며, 타 지역에서 모집된 초등학생 4,536명(남 2,260명, 여 2,276명) 및 중학생 6,551명(남 3,013명, 여 3,538명)을 대상으로 한 번 더 확인적 요인분석을 실시하였다. 세척도 모두 네 개 하위요인으로 구분되었으며 IOS-Q는 17문항, GOS-Q는 19문항, SOS-Q는 18문항을 포함하였다. IOS-Q와 GOS-Q의 하위요인은 심리적 의존, 문제를 인식함에도 조절실패, 위험한 사용, 다른 영역에의 흥미 감소로 명명되었고, SOS-Q의 경우 위험하고 강박적인 사용, 문제를 인식함에도 조절실패, 다른 영역에의 흥미 감소, 금단/내성으로 명명되었다. 이들은 모두 행동중독이나 충동조절장애의 주요 특징들을 잘 반영하는 것으로 보이며, 내적 합치도 역시 .880-.915로 우수한 편이었다. 이어서 고위험군을 선별하기 위한 절단점을 탐색하고자 잠재프로파일분석과 ROC 분석을 실시하였고, IOS-Q 30.5점, GOS-Q 31.5점, SOS-Q는 36.5점이 최적 절단점으로 제안되었다. 끝으로 연구 의의와 한계점을 논하고 후속연구를 제언하였다.

• Clinical and Experimental Pediatrics
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• 제61권11호
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• pp.366-370
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• 2018

Purpose: Tuberculosis (TB) is one of the most important diseases that cause significant mortality and morbidity in young children. Data on TB transmission from an infected child are limited. Herein, we report a case of disseminated TB in a child and conducted a contact investigation among exposed individuals. Methods: A 4-year-old child without Bacille Calmette-$Gu{\acute{e}}rin$ vaccination was diagnosed as having culture-proven disseminated TB. The child initially presented with symptoms of inflammatory bowel disease, and nosocomial and kindergarten exposures were reported. The exposed individuals to the index case were divided into 3 groups, namely household, nosocomial, or kindergarten contacts. Evaluation was performed following the Korean guidelines for TB. Kindergarten contacts were further divided into close or casual contacts. Chest radiography and tuberculin skin test or interferon-gamma-releasing assay were performed for the contacts. Results: We examined 327 individuals (3 household, 10 nosocomial, and 314 kindergarten contacts), of whom 18 (5.5%), the brother of the index patient, and 17 kindergarten children were diagnosed as having latent TB infection (LTBI). LTBI diagnosis was more frequent in the children who had close kindergarten contact with the index case (17.1% vs. 4.4%, P=0.007). None of the cases had active TB. Conclusion: This is the first reported case of TB transmission among young children from a pediatric patient with disseminated TB in Korea. TB should be emphasized as a possible cause of chronic diarrhea and failure to thrive in children. A national TB control policy has been actively applied to identify Korean children with LTBI.

• 대한한의학원전학회지
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• 제31권4호
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• pp.79-90
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• 2018

Objectives : In present, various definitions of Zhongshu are being used interchangeably in Korea. The paper attempted to discover the disease of Zhongshu as studied by Lidongyuan, who was ahead of his time. Methods : A database of medical books has been studied to find Lidongyuan's writings on the disease of Zhongshu, and mentions about Li's works in past medical books. The paper contemplated the subject by defining the disease of Zhongshu and reviewing the disputes related to the subject. Results & Conclusions : Lidongyuan gave a detailed explanation on the fact that Zhangjiegu distinguished between Zhongshu and Zhongre, and this was influenced by Shangshu as mentioned in Taipinghuiminhejijufang. Therefore, it can be deduced that he was aware of the fact that summerheat-heat as latent summer heat syndrome is lurking inside the body, not being able to be released. According to the disease of Zhongshu by Lidongyuan, yin cold was receieved secondary after first receiving summerheat-heat. It is either summerheat damaged defensive qi, failure in storing the essence made defensive qi weak, or seasonal reasons have caused the defensive qi to be drained and leave the body exposed to damage by summerheat. This is because the fundamental main cause is the hitting of summerheat, since yin cold was received after the presence of summerheat-heat is made first. Many doctors in the following generation criticized that Lidongyuan's disease of Zhongshu cannot be named as a Zhongshu due to its similarity with Shanghan. However, they cannot be viewed as similar since it is a phenomenon where yin cold becomes congested while the body is weak and heat is generated in the body due to summerheat-heat. The doctors who said they were similar only focused on the external cause that was only the superficial issue. According to Lidongyuan's method, the right way to treat a Zhongshu disease is to use the method of tonifying the qi and eliminating the heat in conjunction with eliminating the internal dampness or treat the external syndrome, or to use a formula to tonify the qi and eliminate the fire heat before eliminating the internal dampness or treating the external syndrome.

• 한국구조물진단유지관리공학회 논문집
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• 제24권3호
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• pp.47-56
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• 2020

콘크리트 구조물의 주요 열화 현상 중 하나인 염해는 내부 보강재의 부식을 야기하여 최종적으로 구조적 문제를 야기한다. 본 연구에서는 3가지 수준의 물-결합재 비 (0.37, 0.42, 0.47) 및 GGBFS 치환률 (0 %, 30 %, 50 %)을 고려한 콘크리트를 대상으로 재령 1,095일에 촉진염화물 확산 시험을 수행하였다. Tang's method와 ASTM C 1202에 준하여 각 배합의 촉진 염화물 확산계수 및 통과 전하량을 평가하였으며 선행 연구의 이전재령일 시험결과와의 고찰을 통해 재령의 증가에 따라 변화하는 내구성능 거동을 고찰하였다. 재령일이 증가함에 따라 통과 전하량과 확산계수는 크게 감소하였으며, 특히 GGBFS를 혼입한 배합에서는 잠재 수경성에 의해 OPC 배합 대비 큰 폭의 감소가 나타났다. 또한 OPC 배합의 통과 전하량 평가 결과의 경우, 재령 1,095일에서도 "Moderate" 등급에 포함되는 배합이 존재하기 때문에 OPC를 단독으로 사용하는 경우 염해에 취약한 것으로 사료된다. 본 연구에서는 촉진 염화물 확산계수 평가 결과를 기반으로 시간의존성지수를 도출하고 설계변수를 확률함수로 가정하여 결정론 및 확률론적 내구수명 해석을 수행하였다. 확률론적 내구수명 해석 시에는 MCS (Monte carlo Simulation)을 이용하여 내구성 파괴확률을 계산하여 내구수명을 도출하였다. 확률론적 내구수명은 결정론적 내구수명 대비 낮은 값을 나타내었는데 이는 목표 파괴 확률을 10 %로 매우 낮게 설정하였기 때문이다. 구조물의 용도에 적합한 목표 파괴확률을 설정하고 설계변수별로 적절한 변동성을 고려할 수 있다면 더욱 경제적인 설계가 가능해지리라 사료된다.

• 영재교육연구
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• 제21권1호
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• pp.57-81
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• 2011

본 연구의 목적은 음악영재들이 경험하는 일상을 통해 그들이 실제 인지하는 삶의 질에 대해 알아보는 것이다. 삶의 질에 대해 측정하기 위해 일상 경험을 2가지로 나누어 살펴보았다. 하나는 외적 경험으로, 주된 활동, 함께한 사람에 대한 것이며, 다른 하나는 내적 경험으로, flow, 정서에 관한 것이다. 본 연구결과를 통해 음악영재들의 삶(일상)을 정리해 보면 다음과 같다. 첫째, 일상에서 생산활동에 참여하는 시간과 혼자 보내는 시간이 많고, 그 시간에 재능 발현을 위한 준비를 하면서 긍정적인 내적 경험을 하고 있었다. 둘째, 음악영재는 일상에서 일반청소년에 비해 긍정적인 내적 경험을 보고하고 있었다. 셋째, 다른 활동을 할 때보다 자신의 재능과 관련된 음악활동을 하면서 더 깊이 flow에 빠지고, 긍정적인 정서를 느끼고 있었다. 넷째, 음악활동을 하면서 깊은 flow를 경험하고 있었지만, 상대적으로 행복하다고 생각하지는 않았다. 이는 행복감이라는 것이 flow 경험과 동시에 오지 않는 특징을 가졌기 때문으로 보인다. 본 연구는 새로운 연구방법, 즉 경험표집법(ESM)의 사용으로 일상에 대한 풍부하고 심도 깊은 자료를 제공하고, 이러한 정보들을 통해 음악영재들을 심층적으로 이해하고 상담이나 교육을 위한 기초자료를 제공해 줄 수 있을 것이다.