• 한국압력기기공학회 논문집
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• 제10권1호
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• pp.37-43
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• 2014

Nuclear power plants(NPPs) are consisted of power production functions and safety functions preventing leakage of radiation. Operators working in NPPs shall maintain these functions during an operation period through various activities such as improvement & modification, corrective maintenance, preventive maintenance and surveillance test. According to the performance of these work activities, there are configuration changes in NPPs systems. Its changes cause the increase of safety risks(CDF) and plant trip risks. Recently, the importance of risk management is increasing gradually in the operation process of NPPs. Therefore, this paper presents the work management methods using the various risk monitoring systems during power operation and overhaul period. Also this paper suggests the optimum application ways of risk systems for work management.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제20권2호
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• pp.107-121
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• 2016

We analyze the complexity of the LLL algorithm, invented by Lenstra, Lenstra, and $Lov{\acute{a}}sz$ as a a well-known lattice reduction (LR) algorithm which is previously known as having the complexity of $O(N^4{\log}B)$ multiplications (or, $O(N^5({\log}B)^2)$ bit operations) for a lattice basis matrix $H({\in}{\mathbb{R}}^{M{\times}N})$ where B is the maximum value among the squared norm of columns of H. This implies that the complexity of the lattice reduction algorithm depends only on the matrix size and the lattice basis norm. However, the matrix structures (i.e., the correlation among the columns) of a given lattice matrix, which is usually measured by its condition number or determinant, can affect the computational complexity of the LR algorithm. In this paper, to see how the matrix structures can affect the LLL algorithm's complexity, we derive a more tight upper bound on the complexity of LLL algorithm in terms of the condition number and determinant of a given lattice matrix. We also analyze the complexities of the LLL updating/downdating schemes using the proposed upper bound.

• 한국주거학회논문집
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• 제21권4호
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• pp.81-88
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• 2010

Recently, house demander's needs has diversified in the increasingly by the drastic change in the social environment, changes in family structure and population, the growing interest of living environment. So in the future, housing supply to respond to a variety of housing needs is absolutely necessary to differentiate. The purpose of this study is to analyze the lifestyle types of middle-aged married women with high purchasing power in the current housing market and propose the dwelling style by housing awareness and needs analysis. To collect the data, LOV survey method was used for 528 residents in Seoul and metropolitan area. The data analysis used SPSS PC 14.0 to find the frequency, chi-square, factor analysis, and cluster analysis. The results of analysis are as follows: First, the lifestyle was segmented into four groups such as Conservative goal-achieving lifestyle, Individual self-developing lifestyle, Positive self-trusting lifestyle, Outgoing trend-seeking lifestyle. Second, largely the dwelling style according to lifestyle types was divided into living room-kids room type and living room-kitchen type. Third, there were different preferences on the each type of housing space and the $\alpha$-space by different clusters.

• Nuclear Engineering and Technology
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• 제54권4호
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• pp.1261-1270
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• 2022

This study was conducted to investigate the possibility of using gaze entropy to evaluate an operator's situation awareness in an emergency accident situation of a nuclear power plant. Gaze entropy can be an effective measure for evaluating an operator's situation awareness at a nuclear power plant because it can express gaze movement as a single comprehensive number. In order to determine the relationship between situation awareness and gaze entropy for an emergency accident situation of a nuclear power plant, an experiment was conducted to measure situation awareness and gaze entropy using simulators created for emergency accident situations LOCA, SGTR, SLB, and LOV. The experiment was to judge the accident situation of nuclear power plants presented in the simulator. The results showed that situation awareness and Shannon, dwell time, and Markov entropy had a significant negative correlation, while visual attention entropy (VAE) did not show any significant correlation with situation awareness. The results determined that Shannon entropy, dwell time entropy, and Markov entropy could be used as measures to evaluate situation awareness.

• Journal of Ecology and Environment
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• 제37권2호
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• pp.69-79
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• 2014

Soil organic carbon (SOC) in the Arctic is vulnerable to climate change. However, research on SOC stored in the high Arctic regions is currently very limited. Thus, this study was aimed at understanding the distribution and characteristics of SOC with respect to geomorphology and vegetation in Svalbard. In August 2011, soil samples were collected near the Vestre Lov$\acute{e}$nbreen moraine. Sampling sites were chosen according to altitude (High, Mid, and Low) and differences in levels of vegetation establishment. Vegetation coverage, aboveground biomass, and SOC contents were measured, and density-size fractionation of SOC was conducted. The SOC content was the highest in the Mid site ($126.9mg\;g^{-1}$) and the lowest in the High site ($32.1mg\;g^{-1}$), although aboveground biomass and vegetation coverage were not different between these two sites. The low SOC content measured at the High site could be related to a slower soil development following glacial retreat. On the other hand, the Low site contained a high amount of SOC despite having low vegetative cover and a high ratio of sand particles. These incompatible relationships between SOC and vegetation in the Low site might be associated with past site disturbances such as runoff from snow/glacier melting. This study showed that geomorphological features combined with glacier retreat or melting snow/glacier effects could have affected the SOC distribution and vegetation establishment in the high Arctic.

• 한국미생물·생명공학회지
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• 제39권3호
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• pp.281-286
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• 2011

발효새우젓의 에탄올 추출물이 지질대사 개선 효능을 알아보기 위하여 흰쥐에 고지방사료를 식이 시키고 추출물의 경구투여 시킨 후, 혈중 지질 관련 물질의 변화를 측정하였다. 혈청 총 콜레스테롤 함량은 고지방 식이를 급여한 HC, HC-SFSL, HC-SFSH, HC-Lov군 모두 7일차, 14일차에 대조군(NC) 보다 유의하게 증가하였다. HC-SFSH군은 7일차에 330 mg/dl, 14일차에는 277 mg/dl로 HC군에 비하여 31.5%, 40.4%의 유의한 저하효과가 관찰되었으며 양성 대조군인 lovastatin보다 감소율 대비 12.6배 높은 혈중 총 콜레스테롤 저하 효과를 나타내었다. 혈중 TG 함량은 7일차에 HC-SFSL군, HC-SFSH군 그리고 HC-Lov군에서 62 mg/dl, 30 mg/dl, 55 mg/dl로 HC군 85 mg/dl에 비해 각각 27%, 64.7%, 35.2%의 유의성 있게 감소하였다. 혈중 LDL-콜레스테롤 함량은 HC-SFSH군에서 고지방만 급여한 HC군 보다 7일차에 22.4%, 14일차에 36.3% 감소 하였으며 양성 대조군인 lovastatin 투여군 보다 혈중 LDL-콜레스테롤 수치를 2.4~3.2배 감소시키는 것으로 나타났다. 고지방 및 새우젓 에탄올 추출물을 14일간 투여 후 간의 조직학적 관찰을 한 결과, 일반식이를 급여한 NC군의 간조직 세포는 간정맥을 중심을 향하여 규칙적 배열을 이루고 있었으며, 간세포의 핵은 중심에 위치하고 세포질은 균질된 구조였다. 반면 고지방 식이만 급여한 HC군의 간 조직은 간조직의 지방입자가 전체적으로 지방구를 형성하며 세포핵이 한쪽으로 치우쳐져 있으며 세포질도 많이 파열되어 전형적인 지방간 형태를 나타내었다. 특히 HC-SFSH군의 간조직은 HC군에 비하여 지방구의 숫자와 세포질의 파열정도가 뚜렷하게 감소된 것이 관찰되었다.

• 한국유통학회지:유통연구
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• 제15권3호
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• pp.111-137
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• 2010

본 연구는 서비스 시장에서의 지각된 품질과 개인가치간의 인과적 관계 및 고객의 인지욕구에 따른 온 오프라인상의 조절효과에 대해 실증분석하였으며 이를 통해 개인가치에 대한 서비스 전략과 마케팅 관리의 중요성을 제시하고 있다. 서비스 시장에서 서비스 제공자와 구매자간의 장기적 거래관계의 중요성이 크게 부각됨에 따라 관계구축 및 강화에 매우 중요한 역할을 하는 개인가치에 관한 연구는 학계뿐만 아니라 실무적으로도 고객관계관리의 관점에서 시사하는 바가 크다고 할 수 있다. 실증분석을 위해 대형마트(할인점)와 인터넷 쇼핑몰을 이용하는 고객을 대상으로 설문을 통해 데이터를 수집하였으며 온 오프라인의 비교분석을 통한 차이검증을 위한 인과적 구성모델에 대해 구조방정식 모델분석을 통해 가설검증하였다. 구성모델에 대한 분석결과 물리적 환경, 상호작용 품질, 그리고 결과품질로 구성된 지각된 품질은 안정적 삶, 사회적 인식, 사회적 통합으로 구성된 서비스 개인가치에 통계적으로 매우 유의한 정(+)의 영향을 미치는 것으로 나타났으며 집단간 차이효과분석을 통해서도 온 오프라인에 따른 조정효과는 온라인에서보다는 오프라인에서 더 유의한 것으로 나타났다. 그리고 온라인상에서의 서비스에 대한 인지욕구가 높을 때보다는 오프라인상에서의 서비스에 대한 인지욕구가 높을 때 개인가치에 더 유의한 영향을 미치는 것으로 나타났다. 마지막으로 본 연구의 구성모델에 대한 적합도 역시 수용할만한 수준인 것으로 나타났다.