• Korean Journal of Materials Research
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• v.7 no.11
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• pp.1007-1011
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• 1997

영활화혁발전소 보일러헤다 재질인 1Cr0.5Mo강의 파형에 따른 저주기 피로특성을 규명하고자 상온(298K) 및 고온(177K)의 삼각파와 사인파형 저주기 피로시험을 수행하였고 소성에너지법을 이용하여 파형에 따른 소성변형에너지와 피로수명과의 +관계를 분석하였다. 저주기 피로시 재료내부의 소성변형에너지를 히스테리시스루프의 면적으로 계산하여 구하였으며 이를통해 저주기 피로수명을 예측하였고 Coffin-Manson법 및 변형률분할법을 이용한 저주기 피로수명 결과와 서로 잘 일치하였다. 또한 상온 및 고온에서 피로반복수의 증가와 함께 재료가 반봅연화됨을 알 수 있었다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2016.05a
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• pp.174-177
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• 2016

해양사고 관련 주요 통계에서 선원 피로는 해양사고의 주요 원인으로 보고되고 있다. IMO MSC 74차 회의에 피로에 관한 지침서(Guidelines on Fatigue)를 최종 승인되었고, 최근 호주와 한국을 중심으로 지침서에 대한 개정 논의를 진행 중에 있다. 본 논문에서는 이러한 선원 피로의 주요 원인인 업무부하를 선종별 운항형태에 따라 분석한 결과를 소개하고자 한다.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.13 no.2
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• pp.1-18
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• 2017

Metal fatigue is an important aging mechanism that material characteristics can be deteriorated when even a small load is applied repeatedly. An accurate fatigue evaluation is very important for component structural integrity and reliability. In the design stage of a nuclear power plant, the fatigue evaluations of the Class 1 components have to be performed. However, operating experience shows that the design evaluation can be very conservative due to conservatism in the transient severity and number of occurrence. Therefore, the fatigue monitoring system has been considered as a practical mean to ensure safe operation of the nuclear power plants. The fatigue monitoring system can quantify accumulated fatigue damage up to date for various plant conditions. The purpose of this paper is to describe the fatigue monitoring procedure and to introduce the fatigue monitoring program developed by the authors. The feasibility of the fatigue monitoring program is demonstrated by comparing with the actual operating data and finite element analysis results.

• Journal of the Korea Convergence Society
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• v.10 no.5
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• pp.189-201
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• 2019

The aim of this study is to investigate the relationship between communication motive, fatigue and loneliness in mobile environment. According to previous research, the most important communication motive in mobile environment is pleasure. Therefore, pleasure was selected as a representative communication motive. To do this, we collected data for empirical analysis from mobile messenger users using questionnaire. We found that pleasure has a negative effect on loneliness. Second, pleasure has a negative effect on connection, function, and focus. On the other hand, pleasure has no effect on delivery and relationship fatigue. Finally, function and focus have a positive effect on loneliness. On the other hand, connection, delivery, and relationship fatigue have no effect on loneliness. As a result of the research, it is possible to reduce the function and focus fatigue due to the use of the mobile messenger by adding the functions that cause the enjoyment of using the messenger. In addition, the addition of fun-inducing features can also reduce loneliness caused by the use of mobile messenger. Future research will also need to identify factors that may reduce connection and relationship fatigue.

• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.4
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• pp.135-143
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• 2004

In this paper, 6 span SCP continuous girder bridge's structural behavior were studied by analytic and experimental method To study structural behavior of SCP girder, we used PSC theory and steel girder theory. To examine slab concrete crack, concrete stress, and fatigue stress of steel, we achieved a static load and fatigue test. In the result, 6 span SCP girder bridge connected at the interior support about actuality bridge have enough structural capacity under service loads.

• Journal of Korean Ophthalmic Optics Society
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• v.10 no.1
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• pp.71-82
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• 2005

The aim of this study was to provide fundamental data for the factors influencing the asthenopia of emmetropia with phoria and alleviation of asthenopia. A total of 348 subjects, aged between 19 and 30 years old, who had no strabismus, an eye trouble or whole body disease, were examined using corrected visual acuity, corrected diopter, stereopsis and suppression tests from September of 2002 to September of 2004. We excluded 21 subjects for the following reasons: if they had an amblyopia affecting binocular vision or inaccurate data. After these exclusions, 327 subjects remained. We then individually measured the refractive error correction, pupillary distance, optical center distance, phoria, convergence, accommodation and the AC/A as well as the asthenopia during binocular vision using a questionnaire. After analysis of factors affecting asthenopia, we also examined the reductive effect of a prism on the asthenopia in subjects who had asthenopia. To determine the factors affecting asthenopia during binocular vision, statistic analyses were carried out using the Chi-square test and the multivariate Logistic regression model. The results of this study were as follow. For asthenopia during near binocular vision of emmetropia with phoria, in case of the lower the accommodation and convergence, a significantly higher rate of asthenopia was observed (p<0.001). When the AC/A is lower, the higher the rate of asthenopia was observed but not significantly and there was no association between phoria and asthenopia. When the multivariate logistic regression model was used to determine factors affecting binocular vision of emmetropia with phoria, in case of the lower accommodation and convergence, a significantly higher rate of asthenopia was observed. when the phoria is esophoria or higher exophoria, or when the AC/A is lower than normal, the higher the rate of asthenopia was observed but not significantly and there was no association between phoria. AC/A and asthenopia. Therefore accommodation and convergence could be predictive factors for asthenopia during near distance binocular vision. Prism was used among' subjects who had asthenopia during near distance binocular vision, the symptom of asthenopia was eased up to 74.2% in emmetropia with phoria.

• Journal of the Korean Society of Marine Environment & Safety
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• v.10 no.2 s.21
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• pp.1-6
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• 2004

For many years, fatigue was discounted as a potential cause of or contributor to human error. However, resent accident data and research point to fatigue as a cause of and/or contributor to human error precisely because of its impact on performance. The goal of this study is to analyze and examine of the fatigue factors related to human error. In this study, we carried out the questionnaire sw-vey which concerned with the fatigue factors.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.29 no.1
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• pp.95-100
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• 2005

For many years, fatigue of ship's crew was discounted as a potential cause of or contributor to human error. However, resent accident data and research point to fatigue as a cause of and/or contributor to human error precisely because of its impact on performance. The goal of this study is to analyze and examine of the fatigue factors related to human error. In this study, we carried out the questionnaire survey which concerned with the fatigue factors.

• Proceedings of KOSOMES biannual meeting
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• 2004.11a
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• pp.89-94
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• 2004

For many years, fatigue was discounted as a potential cause of or contributor to human error. However, resent accident data and research point to fatigue as a cause of and/or contributor to human error precisely because of its impact on performance. The goal of this study is to analyze and examine of the fatigue factors related to human error. For this, we carried out the questionnaire survey which concerned with the fatigue factors.

• Journal of the Korea Convergence Society
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• v.10 no.8
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• pp.21-26
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• 2019

This paper proposes a fatigue recognition method using the C4.5 algorithm. Based on domestic and international studies on fatigue evaluation, we have completed the fatigue self - assessment scale in combination with lifestyle and cultural characteristics of Chinese people. The scales used in the text were applied to 58 sub items and were used to assess the type and extent of fatigue. These items fall into four categories that measure physical fatigue, mental fatigue, personal habits, and fatigue outcomes. The purpose of this study is to analyze the leading causes of fatigue formation and to recognize the degree of fatigue, thereby increasing the personal interest in fatigue and reducing the risk of cerebrovascular disease due to excessive fatigue. The recognition rate of the fatigue recognition system using the C4.5 algorithm was 85% on average, confirming the usefulness of this proposal.