• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.141-142
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• 2022

열화란 윤활유의 물리적, 화학적 성질이 변하면서 성능이 저하되는 현상을 말합니다. 물리적 변화는 연료유, 수분, 금속 등 이물질 혼입으로 발생되며 화학적 변화는 산화 현상이 대표적이며 슬러지 등을 발생합니다. 해경 경비함정은 장시간 항해, 해상조건등에 따라 엔진의 부하변동이 많습니다. 따라서 윤활유의 역할이 매우 중요합니다. 그러나 연료혼입 등으로 윤활유가 열화되면서 수명이 단축되게 됩니다. 따라서 본 연구에서는 대표적 물리적 변화의 요인인 연료혼입를 실험적으로 고찰하고자 윤활유에 연료를 일정비율로 혼합하여 물성시험 등을 수행하였습니다. 실험결과 동점도는 윤활유에 점도가 낮은 연료유 혼입량이 증가함에 따라 점진적으로 감소하는 경향을 보였습니다.

• Journal of Intelligence and Information Systems
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• v.21 no.3
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• pp.19-36
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• 2015

Social media is an emerging issue in content services and in current business environment. YouTube is the most representative social media service in the world. YouTube is different from other conventional content services in its open user participation and contents creation methods. To promote a content in YouTube, it is important to understand the diffusion phenomena of contents and the network structural characteristics. Most previous studies analyzed impact factors of contents diffusion from the view point of general behavioral factors. Currently some researchers use network structure factors. However, these two approaches have been used separately. However this study tries to analyze the general impact factors on the view count and content based network structures all together. In addition, when building a content based network, this study forms the network structure by analyzing user comments on 22,370 contents of YouTube not based on the individual user based network. From this study, we re-proved statistically the causal relations between view count and not only general factors but also network factors. Moreover by analyzing this integrated research model, we found that these factors affect the view count of YouTube according to the following order; Uploader Followers, Video Age, Betweenness Centrality, Comments, Closeness Centrality, Clustering Coefficient and Rating. However Degree Centrality and Eigenvector Centrality affect the view count negatively. From this research some strategic points for the utilizing of contents diffusion are as followings. First, it is needed to manage general factors such as the number of uploader followers or subscribers, the video age, the number of comments, average rating points, and etc. The impact of average rating points is not so much important as we thought before. However, it is needed to increase the number of uploader followers strategically and sustain the contents in the service as long as possible. Second, we need to pay attention to the impacts of betweenness centrality and closeness centrality among other network factors. Users seems to search the related subject or similar contents after watching a content. It is needed to shorten the distance between other popular contents in the service. Namely, this study showed that it is beneficial for increasing view counts by decreasing the number of search attempts and increasing similarity with many other contents. This is consistent with the result of the clustering coefficient impact analysis. Third, it is important to notice the negative impact of degree centrality and eigenvector centrality on the view count. If the number of connections with other contents is too much increased it means there are many similar contents and eventually it might distribute the view counts. Moreover, too high eigenvector centrality means that there are connections with popular contents around the content, and it might lose the view count because of the impact of the popular contents. It would be better to avoid connections with too powerful popular contents. From this study we analyzed the phenomenon and verified diffusion factors of Youtube contents by using an integrated model consisting of general factors and network structure factors. From the viewpoints of social contribution, this study might provide useful information to music or movie industry or other contents vendors for their effective contents services. This research provides basic schemes that can be applied strategically in online contents marketing. One of the limitations of this study is that this study formed a contents based network for the network structure analysis. It might be an indirect method to see the content network structure. We can use more various methods to establish direct content network. Further researches include more detailed researches like an analysis according to the types of contents or domains or characteristics of the contents or users, and etc.

• Journal of the Korea Convergence Society
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• v.10 no.11
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• pp.501-510
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• 2019

This study aimed to find health related lifestyle factors that influence glycemic control for diabetes mellitus (DM) management strategies. This study used nested case-control design with matching variables that were not controlled by individuals such as age, sex, insulin or oral hypoglycemic agent (OHA) use, disease duration, education level and household income. This study analyzed 983 subjects with type 2 DM who enrolled in the $7^{th}$ (2016-2017) Korean National Health and Nutrition Examination Survey (KNHANES). The target HbA1c level of controlled glucose was defined as less than 6.5%, and 289 (30%) were achieved. Conditional multivariable logistic regression analysis was performed to find self-control factors associated with HbA1c levels. The results statistically significant for variables such as duration of diabetes, insulin or OHA use in overall cohort and body mass index (BMI), smoking and fundus Examination in matched cohort. These results are expected to provide as evidence for the intensive care criteria(disease duration, drug use) and lifestyle management strategy(BMI, smoking, fundus examination).

• Journal of Digital Convergence
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• v.16 no.11
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• pp.383-392
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• 2018

This study investigates convergent factors to TOEIC learning flow among some health college students in TOEIC class. The questionnaire was performed on 255 health college students in TOEIC class from college located in J area from May 1st, 2018 to May. 25th, 2018 by using an unregistered self-administered questionnaire. The hierarchical multiple regression analysis shows the following results. The TOEIC learning flow of respondents turned out to be significantly higher in following groups: a group in which self efficacy is higher, a group in which academic control is higher, a group in which school resilience is higher. The results show explanatory power of 43.4%. As the results of the study, it is necessary to make an effort to increase self efficacy, academic control and school resilience to improve the TOEIC learning flow among health college students. These results can be used in development and operation of TOEIC learning program to higher TOEIC learning flow in health college students. Further studies need the analysis of structural equation model effecting TOEIC learning flow of health college students.

• 한국노년학
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• v.40 no.4
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• pp.781-800
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• 2020

This study aims to categorize the daily time use of older adults into different types, examine the factors influencing them and the differences between them by type, and verify the effect of each type on life satisfaction. From the 6th wave of the Korea Retirement and Income Study (KeRIS), analysis was conducted on 3,963 older adults aged 65 (n=3,963). Using Latent Profile Analysis (LPA), three types of daily time use for older adults were identified: basic life maintenance type (16%), free-leisure oriented type (26%), and social activity type (58%). From the results of multinomial logistic regression analysis to identify the factors influencing each type of daily time use, it was found that the main factors influencing free-leisure oriented type, when compared with basic life maintenance type, were the presence of spouse (p<.01) and psychological health status (p<.001). The main factors influencing social activity type, when compared with basic life maintenance type, were age (p<.05), economic activity (p<.001), and chronic disease (p<.001). The life satisfaction seen during free-leisure oriented time and social activity time was higher than that during basic life maintenance time. From these findings, practical and policy proposals were suggested to improve life satisfaction of older adults during basic life maintenance time by pursuing changes in the use of that time.

• Journal of the Korean Society for Marine Environment & Energy
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• v.5 no.1
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• pp.30-37
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• 2002

Recently, there have been frequent environmental threats associated with the red tide. The discharge of bilge water and waste lubricating oil from fishing vessels is known to be the major cause of such problems. In oder to treat those wastes, post processing units at harbours are being considered, and an accurate prediction of the amount of such wastes is required. In this paper we have proposed a method to estimate the amount of bilge water and waste lubricating oil from fishing vessels. We identified the key parameters affecting the quantity of oily bilge water and waste lubricating oil, and proposed a prediction model. We applied the present model to estimate the quantity of oily bilge water and waste lubricating oil in the sample fishing port.

• 월간낙농육우
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• v.18 no.11 s.199
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• pp.76-76
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• 1998

최근 제주도의 한우 및 경기도, 강원도, 충청도 일부지역 젖소에서 유$\cdot$조산 발생이 부루세라 백신접종과 개연가능성이 있으나, 소의 유$\cdot$조산 발생원인은 세균성, 바이러스성, 원충성 등 그 요인이 매우 다양하여 원인규명이 쉽지 않은 실정입니다. 특별대책반에서는 정확한 발생 원인규명 중에 있으나 농가의 우선 예방치료 조치로서 향균제 치료 및 철저한 소독 등을 통하여 피해가 확산되지 않도록 예방치료를

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.223-223
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• 2010

태양 전지에 사용되는 실리콘의 전자기 유도 용융 기술은 잉곳(ingot)의 성장 및 금속 정련 등의 핵심 공정인 실리콘 용융에서 사용되는 중요한 기술이다. 하지만, 유도 용융에 사용되는 흑연 도가니에 의한 실리콘의 오염은 실리콘의 순도저하에 요인으로 작용한다. 흑연 도가니와 용융된 실리콘이 접하는 계면에서 탄소의 오염이 발생하게 되며, 실리콘 내부에 흡수한 탄소는 대표적인 비금속 불순물로 태양전지 효율을 감소시킨다. 본 연구에서 사용되는 흑연 도가니는 유도 코일의 전자기력에 의해 실리콘과 무접촉 또는 연접촉이 가능한 구조이다. 또한, 유도 자기장을 이용하여 실리콘과 같은 반도체를 용융할 경우, 고상에서의 낮은 전기전도도로 인해 효과적인 줄-발열(Joule Heating)이 불가능하므로 플라즈마와 같은 보조 열원을 필요로 한다. 본 연구에서는, 보조 열원 없이 세그먼트(segment)된 흑연 도가니를 이용한 실리콘 용융 연구를 진행하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.1842-1843
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• 2015

심해 유인 잠수정과 같은 제한된 공간 내에서 다수의 작업자가 장시간 거주하며 작업을 수행하기 위해서는 거주구 관측창 위치 및 기타 운영설비 배치에 있어 인체공학적 설계가 고려되어야 한다. 본 논문에서는 구조안전성 평가와 최적설계로 도출된 심해 유인 잠수정의 내압구조 셀 설계안을 대상으로 거주구 관측창 배치를 위한 인체공학적 설계 검토에 대하여 소개한다. 관측창 배치는 작업자 선내 위치, 관측 시야 확보, 편안하고 안전한 작업 여부 등의 다양한 요인과 함께 구조 안전성과 제작성 등이 동시에 고려되어야 한다. 국외 심해 잠수정 개발에서 적용된 인체공학적 설계 관련연구를 소개하고 디지털 휴먼 모델링 S/W인 Santos Engine을 활용한 인체공학적 설계 검토에 대하여 소개한다.

• Korean Journal of Social Welfare Studies
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• v.49 no.1
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• pp.191-219
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• 2018

Although several measurements of happiness at work have been developed as interest in it has grown, most of them only deal with hedonia, emotional pleasure, and there exists no measurement of eudaimonia, ultimate happiness through meaning and worthiness in Korea. This study aims to examine the validity of the Korean version of Global Hedonic and Eudaimonic Job Satisfaction (K-GHEJS) scale which covers both hedonia and eudaimonia at work. Considering the job characteristics of social work which emphasizes the values and meaning of the helping profession, online survey was performed among a total of 376 social workers. Exploratory factor analysis confirmed the goodness-of-fit of 10 items, and confirmatory factor analysis confirmed that classification as two factors of hedonic and eudaimonic job satisfaction is appropriate. The reliability was found to be high as reliability coefficient Chronbach's ${\alpha}$ was .936. This K-GHEJS scale which measures eudaimonic happiness for the first time in Korea, is expected to be useful for measuring job satisfaction of the helping professions such as social work that pursues the values and meanings of work.