• Nuclear Engineering and Technology
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• 제50권5호
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• pp.627-638
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• 2018

This article describes an integrated Level 1-Level 2 probabilistic risk assessment (PRA) methodology to evaluate the radiological risk during postulated accident scenarios initiated during the decommissioning phase of a typical Mark I containment boiling water reactor. The fuel damage scenarios include those initiated while the reactor is permanently shut down, defueled, and the spent fuel is located into the spent fuel storage pool. This article focuses on the integrated Level 1-Level 2 PRA aspects of the analysis, from the beginning of the accident to the radiological release into the environment. The integrated Level 1-Level 2 decommissioning PRA uses event trees and fault trees that assess the accident progression until and after fuel damage. Detailed deterministic severe accident analyses are performed to support the fault tree/event tree development and to provide source term information for the various pieces of the Level 1-Level 2 model. Source terms information is collected from accidents occurring in both the reactor pressure vessel and the spent fuel pool, including simultaneous accidents. The Level 1-Level 2 PRA model evaluates the temporal and physical changes in plant conditions including consideration of major uncertainties. The goal of this article is to provide a methodology framework to perform a decommissioning Probabilistic Risk Assessment (PRA), and an application to a real case study is provided to show the use of the methodology. Results will be derived from the integrated Level 1-Level 2 decommissioning PSA event tree in terms of fuel damage frequency, large release frequency, and large early release frequency, including uncertainties.

• 한국건설관리학회논문집
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• 제5권2호
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• pp.136-143
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• 2004

본 논문은 초기 건설공사의 리스크 관리방법론을 제시한 것으로서, 리스크식별 및 분석을 중심으로 연구를 진행하였다. 리스크식별은 초기 건설공사를 $공통공사\cdot토공사\cdot지정$ 및 기초공사로 구분하여 리스크를 규명하고 작업분류체계에 기반하여 리스크분류체계를 제안하였다. 리스크분석은 리스크분류체계를 바탕으로 퍼지추론을 이용하여 리스크인자의 위험도를 정량화하고 퍼지척도를 이용하여 리스크인자의 중요도를 산정하였으며, 이를 통합하여 상위 리스크인자의 종합위험도를 구하기 위해 퍼지적분을 이용하였다. 리스크인자의 관리 우선순위는 종합위험도로부터 결정할 수 있다. 본 연구에서 제시한 리스크 관리 방법론의 타당성을 확인하기 위하여 사례적용을 실시하였으며, 그 결과 제시한 방법론이 현장 및 공사의 특성을 반영하여 리스크인자의 관리 우선순위를 결정하는데 충분히 활용할 수 있음을 확인할 수 있었다.

• Geomechanics and Engineering
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• 제28권6호
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• pp.573-584
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• 2022

Water inrush may occur during seaside urban tunnel excavation. Various factors affect the water inrush, and the water inrush mechanism is complex. In this study, nine evaluation indices having potential effects on water inrush were analysed. Specifically, the geographic and geomorphic conditions, unfavourable geology, distance from the tunnel to sea, strength of the surrounding rock, groundwater level, tidal action, cyclical footage, grouting pressure, and grouting reinforced region were analysed. Furthermore, a two-step interval risk assessment method for water inrush management during seaside urban tunnel excavation was developed by a multi-index system and interval risk assessment comprised of an interval analytic hierarchy process, fuzzy comprehensive evaluation, and relative superiority analysis. The novel assessment method was applied to the Haicang Tunnel successfully. A preliminary interval risk assessment method for water inrush was performed based on engineering geological conditions. As a result, the risk level fell into a risk level IV, which represents a section with high risk. Subsequently, a secondary interval risk assessment method was performed based on engineering geological conditions and construction conditions. The risk level of water inrush is reduced to a risk level II. The results agreed with the current tunnel situation, which verified the reliability of this approach.

• 한국환경성돌연변이발암원학회:학술대회논문집
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• 한국환경성돌연변이발암원학회 2004년도 KSOT/KEMS Fall Annual Meeting
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• pp.166-166
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• 2004

• 한국산학기술학회논문지
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• 제13권7호
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• pp.3244-3251
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• 2012

대형 해양구조물의 건설과 운영에서 중요한 항목 중의 하나가 재해위험도를 분석하고 평가하는 것이다. 이에 본 연구에서는 수중터널의 건설과 운영 시에 발생할 수 있는 재해 위험요소를 도출하고 퍼지 AHP(Analytic Hierarchy Process) 방법으로 이러한 위험요소의 수준을 파악하고자 하였다. 재해 위험도로는 자연재해 위험도와 인적재해 위험도로 구분하고 이러한 위험도 항목들이 수중터널에 미치는 영향을 전문가 설문을 통하여 조사하였다. 조사된 전문가 설문결과 데이터를 퍼지 AHP 기법으로 분석하여 재해위험도를 각 위험요소별로 정량화하였다. 또한, 수중 터널과 교량, 해저터널, 침매터널의 재해위험도 수준을 분석하여 수중터널이 가지고 있는 고유의 재해위험도 수준을 평가하였다. 재해위험도에서는 쯔나미와 지진이 가장 위험도 인식수준이 높았고, 인적재해 위험도는 화재와 폭발의 위험도 인식이 높은 수준이었다. 또한, 수중터널은 침매터널에 비해서는 1.4배, 교량에 비해서는 3.2배 위험도 인식수준이 높은 것으로 조사되었다.

• 산업경영시스템학회지
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• 제32권2호
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• pp.158-170
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• 2009

This paper considers how the optimal export level is influenced by export risk, the degree of risk-averseness for exporting firms, and those firms' cost structure. In addition, export insurance is incorporated into some simple theoretical model to analyze the optimal export level. This paper applies genetic algorithm simulation to show that the exporting firms'risk-averseness do not affect the optimal export decision while export risk and cost function characteristic have relatively more significant effects on the optimal export level. Finally, our findings suggest that the most influential factor for the optimal export levels seems to be the monopoly power of exporting firms.

• 항공우주시스템공학회지
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• 제16권3호
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• pp.52-62
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• 2022

특정범주 무인항공기 운용의 위험평가를 위해서 개발된 SORA 방법론에서는 지상 및 공중위험 등급을 결정하고 해당 위험도에 대한 특정보증 무결성 수준을 나타내는 SAIL이 할당되어 제안된 운용에 대한 운용 안전도 목표를 적절한 강건도 수준으로 입증해야 한다. 인명의 수송은 제외하는 특정범주 무인항공기 운용의 특성상 지상의 인명이 가장 먼저 고려되어야 하는 위험의 대상이며, 여기서 평가된 지상위험도는 공중위험도와 함께 SAIL의 할당에서도 중요한 역할을 한다. 위험도는 초기에 결정된 등급에 세 가지 종류의 완화수단이 적용되는 것으로 등급이 경감되어 최종 등급이 결정된다. 본 논문에서는 무인항공기의 특정범주 운용에 대한 위험평가 중에서 지상위험 등급의 결정과 완화수단의 적용을 통한 등급의 감소 및 최종 위험 등급에 따른 SAIL과 OSO에 미치는 영향에 대해서 분석하였다.

• 식품보건융합연구
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• 제7권1호
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• pp.17-26
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• 2021

The purpose of this study was to develop strategies and policies for smoking prevention that are tailored to the characteristics of different groups of smokers. The structured survey was conducted with regular smokers. The results were as follows: It has been demonstrated that Risk Perception Attitude framework can be used as a major research framework to predict behavioral changes related to the prevention of smoking. The smokers were divided into four attitude groups based on perceived risks and self-efficacy: indifference, proactive, avoidance, and responsive. The smoker groups showed significant differences in information seeking, information avoidance, prevention behavior and addiction degree. Especially, the difference in prevention behavior depended on the self-efficacy when the perceived risk level was high. Information avoidance was the lowest when the perceived risk level was high and the self-efficacy was low. Information seeking was lowest when the perceived risk level was low. When the level of self-efficacy was high, if the perceived risk level was high, prevention behavior was actively performed. Therefore, the self-efficacy was related to preventive behavior, and the perceived low-risk played a role in hindering information seeking. Smoking prevention strategies are important to raise awareness of the risk of smoking and to improve the positive willingness of smokers to quit smoking through self-efficacy.

• Journal of Nutrition and Health
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• 제37권5호
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• pp.385-393
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• 2004

This study examined the relations of educational level and life-style behaviors to the obesity. A total of 507 male adults aged 30 - 50 years completed the self-reported questionnaires. Educational level was used for measuring socioeconomic status. Activity at work, leisure-time activity and TV watching were measured for life-style behaviors related to physical activity, and some demographic and family history of disease as well. Subjects were categorized as obese when BMI was equal to or over 25kg/$m^2$, in which 19.7％ resulted obesity. Using multivariate logistic regression, the association between the measured factors and obesity was assessed. The odds ratios (OR) for risk of obesity did not differ with either age or monthly income. Subjects who completed high school (OR = 0.36; 95％ CI = 0.20 - 0.66) or university (OR = 0.34; 95％ CI = 0.16 - 0.71) had lower risk of obesity than those with education below middle school. Those with moderate activity level at work (OR = 0.41; 95％ CI = 0.24 - 0.72) showed lower risk of obesity than in inactive ones. The subjects watching TV more than 3.5 hr/day presented higher risk of obesity (OR = 2.46; 95％ CI = 1.28 - 4.74), compared with those watching TV less than 1.5 hr/day. The higher risk of obesity observed in high level of leisure time activity than in low one was considered due to that physical activity at work and leisure-time might counteract each other. Educational level and activity at work or leisure-time activity or TV watching were jointed and categorized, and then OR for obesity was estimated. The extent of obesity risk at a given level of each work activity or leisure-time activity or TV watching was different depending the educational level, which was significantly high when educational level was below middle school. Educational difference had no effect on activity level at work. However, higher educational attainment increased the leisure activity and reduced TV watching (p＜0.05), indicating that low education tended to contribute to more sedentary life-style. The findings of this study is concluded that low education was related to obesity in adult males, and its relation can partly be explained through acquiring inactive life-style behaviors. Individuals with low education might be more susceptible to the risk factors of obesity.

• 품질경영학회지
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• 제41권3호
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• pp.465-474
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• 2013

Purpose: To provide a variety of stable military supplies, risk should be avoided or removed. This paper aims to provide an objective method of risk assesment for risk matrix to evaluate risk level. Methods: According to previous results of risk assesment through risk matrix, some parameters and probability density functions, which include characteristics of military supplies, are selected and Risk matrix is modelled based on that. Results: Results show that a proposed method can evaluate objectively risk level through the stochastic modelling and provide well-balanced risk assessments by categorizing into 3 levels such as high, middle and low level risk. Conclusion: A current risk assessment method includes substantial subjectivity of risk assessment and as a problem about military supplies comes up, we can not show any appropriate evidences for decision of risk assessment. We propose an objective scheme employing stochastic modelling with parameters and probability density functions.