• 한국태양에너지학회 논문집
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• 제30권6호
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• pp.59-65
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• 2010

Analysis on turbulence intensity profile depending on wind speed is an important process to set up design condition of wind turbine in terms of fatigue load. This paper tests goodness of fit of turbulence intensity empirical equations suggested by the IEC 61400 Standards with Jejudo Gimnyeong met-tower measurement, which is erected at a seashore. Therefore sea breeze and land breeze coexist. Sea breeze case showed apparent increasing trend of turbulence intensity in a high wind speed regime due to increase of sea surface roughness. However, neither inland wind turbine standard IEC 61400-1 nor offshore wind turbine standard IEC 61400-3 fit such a trend adequately. On the other hand, the modified empirical equation of turbulence intensity of IEC 61400-3 derived from Germany FINO1 application study by considering turbulence intensity behavior in a high wind speed regime showed good agreement with the measurement. Therefore, we can reconfirm and conclude that IEC 61400-3 Ed.1 legislated in 2009 needs to be modified.

• 대한토목학회논문집
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• 제12권1호
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• pp.71-84
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• 1992

폴리머침투콘크리트는 무기계 시멘트와 유기계 폴리머를 결합시킨 신소재 콘크리트이다. 폴리머 침투콘크리트는 기존 시멘트콘크리트에 비하여 각종 역학적 특성과 내구성이 크게 개선되는 것으로 알려져 있으나, 지금까지는 국부적 강도증진과 보수재의 차원에 머무르고 있는 실정이다. 향후, 각종 고성능 프리캐스트부재의 제조에 폴리머 침투콘크리트를 보다 적극적으로 적용하기 위해서는 고분자모노머의 개발과 폴리머침투콘크리트의 재료특성에 대한 체계적인 정립이 필요하며, 본 연구에서는 이를 위하여 실험결과를 토대로 MMA계의 침투제를 개발하고 폴리머 침투콘크리트의 재료특성을 구명한다.

• 한국직업건강간호학회지
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• 제22권1호
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• pp.57-65
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• 2013

Purpose: The purpose of this study was to evaluate the factors that affected self efficacy, social support and learning achievement in the web-based learning of graduate school students. Methods: The data were collected from 79 nurses in a web-based learning. A self-reported questionnaire was used to assess the level of self-efficacy, social support and learning achievement. Results: The learning achievement was significantly improved to 4.05 points after web-based learning compared to 2.69 points before web-based learning, and all other items were also improved. Self-efficacy was improved to 3.91 points from 3.66 points after web-based learning and so was social support to 4.18 points from 3.94 points. Fatigue and stress among health behavior characteristics were significantly decreased after web-based learning. Conclusion: This study shows that the web-based learning improved self-efficacy and social support of the students. And self-efficacy was an important factor in learning achievement. It is necessary to develop a strategy to improve self-efficacy as well as to manage social support for increasing interactions among the nurses in a web-based learning.

• 말소리와 음성과학
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• 제5권4호
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• pp.53-61
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• 2013

Voice disorders are most common in female teachers due to work-related vocal demands; however, only a few studies tried to evaluate individual risk factors with work-related risk factors to diagnose voice disorders. This study evaluated sixty-seven female elementary teachers (36 with voice disorders and 31 without voice disorders) to compare their vocal misuse, overuse, and vocal hygiene behaviors. Total Voice Handicap Index scores and VHI subscale (P, E, F) scores were not significantly different between two groups (p>0.05) and there was no relationship between VHI and acoustic measures (p>0.05). Loud talking, talking in noisy situations, and excessive speaking were significantly more frequent in female teachers with voice disorders (p<0.05) and thereby these overuse and misuse behavioral patterns were identified as risk factors to develop voice disorders in female teachers. Also, hydration was the most common behavior for vocal hygiene when experiencing vocal fatigue; however, hydration with hot green tea or coffee and throat clearing were often misused for vocal hygiene. This study found that female teachers from both groups presented higher voice handicap regardless of voice disorders. This study suggests a multidimensional voice assessment protocol is required to reflect voice problems in teachers and a vocal education program may be important to improve vocal hygiene knowledge and behavioral changes in female teachers.

• Journal of Preventive Medicine and Public Health
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• 제40권5호
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• pp.351-362
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• 2007

Objectives: The present study was intended to assess the mental health of nurses working for university hospitals and to establish which factors determine their mental health. Methods: Self-administered questionnaires were given to 1,486 nurses employed in six participating hospitals located in Daejeon City and Chungnam Province between July 1 st and August 31st, 2006. The questionnaire items included sociodemographic, job-related, and psychosocial factors, with job stress factors (JCQ) as independent variables and indices of mental health status (PWI, SDS and MFS) as dependent variables. For statistical analysis, the Chi-square test was used for categorical variables, with hierarchical multiple regression used for determining the factors effecting mental health. The influence of psychosocial and job-related factors on mental health status was assessed by covariance structure analysis. The statistical significance was set at p<0.05. Results: The factors influencing mental health status among subject nurses included sociodemographic characteristics such as age, number of hours of sleep, number of hours of leisure, and subjective health status; job-related characteristics such as status, job satisfaction, job suitability, stresses such as demands of the job, autonomy, and coworker support; and psychosocial factors such as self-esteem, locus of control and type A behavior patterns. Psychosocial factors had the greatest impact on mental health. Covariance structure analysis determined that psychosocial factors affected job stress levels and mental health status, and that the lower job stress levels were associated with better mental health. Conclusions: Based on the study results, improvement of mental health status among nurses requires the development and application of programs to manage job stress factors and/or psychosocial factors as well as sociodemographic and job-related characteristics.

• 지역사회간호학회지
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• 제20권4호
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• pp.465-473
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• 2009

Purpose: The purpose of the study was to investigate the relationships between worker's health belief in health promotion programs and their demographic, health, and health behavior characteristics. Methods: This study used survey data from 262 small- and large-scale workplaces. The study included 1149 male and female workers who completed the questionnaires. Results: The health belief score increased significantly with age and length of service. Male, married, shift-work, and white-collar workers showed a significantly higher health belief score than female, single, non-shift-work, and blue-collar ones. Workers with disease history, hypertension, or obesity had a significantly higher health belief score. Regular exercise was significantly correlated with the health belief score. When all the variables were included in the model, the health belief score was significantly higher in workers who were married, had a longer length of service, worked in the sales department, were diagnosed with hypertension, exercised regularly, and felt fatigue. Conclusion: The results showed that workplace intervention programs meet more the needs of workers who have a higher health belief score. In addition, given that healthier life style was related to a higher health belief score, further research is required to find how to change health behavior in workers.

• Tribology and Lubricants
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• 제36권1호
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• pp.47-54
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• 2020

In this study, the effects of ultrasonic nanocrystal surface modification (UNSM) treatment at room and high temperatures (RT and HT of 400℃) on friction and wear behavior of Ti-6Al-4V alloy prepared by selective laser melting (SLM) were investigated. The objective of this study is to improve the mechanical properties and frictional behavior of Ti-6Al-4V alloy by UNSM treatment. Dry friction and wear tests were conducted using a ball-on-disk method at RT with a bearing steel as the counter ball. Due to the high HT and UNSM treatment, the surface hardness tended to increase and surface roughness tended to reduce. X-ray diffraction (XRD) analysis showed that nanocrystallization structure and compressive residual stress were formed at the surface layer after UNSM treatment at both RT and HT. After UNSM treatment, it was observed that the wear rate was reduced by about 6% for the specimen treated at RT and a 28% reduction for the specimen treated at HT in comparison with the untreated one. Based on scanning electron microscope (SEM) images showed that the damage caused by fatigue wear occurred in the wear track of the heat-treated specimen, and it is believed to be the cause of the highest wear rate. Mechanical properties and wear resistance of Ti-6Al-4V alloy were improved and prospect of industrial application was confirmed. Further research is still required to improve the characteristics of SLM Ti-6Al-4V alloy to the level of wrought Ti-6Al-4V alloy.

• 한국강구조학회 논문집
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• 제29권6호
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• pp.401-410
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• 2017

본 연구에서는 긴장재로 계류된 해중 터널에서 긴장재의 느슨해짐에 따른 동적 불안정 거동에 대해 다룬다. 해중 터널의 설계는 파랑 및 조류 등 유체력에 의해 지배받는다. 특히 시간에 따라 지속적으로 크기 및 작용방향이 변하는 파랑은 해중 터널의 동적 거동을 직접적으로 야기하게 되는데, 파랑에 의한 부유 튜브의 운동은 계류선 내력의 동적 변동을 유발하게 되고, 이 힘의 변화는 계류선의 강도설계 뿐 만 아니라 피로 설계에도 직접적인 영향을 미친다. 파랑에 의한 터널의 운동이 극심할 경우, 계류선의 장력은 모두 소실될 수 있는데, 이 때 계류선이 느슨해짐에 따라 일시적으로 부유 터널의 운동에 대한 저항성이 사라져 동적 불안정 거동이 유발 될 수 있다. 이에 본 연구에서는 유체-구조동역학 해석기법을 통해 해중 터널 긴장재의 느슨해짐 발생 시 부유 튜브의 동적 불안정 거동에 대해 분석하였다. 특히 해중터널의 중요 설계 인자인 흘수, 부력-자중 비율(Buoyancy-Weight Ratio, BWR), 긴장재 기울임이 동적 불안정 거동에 미치는 영향에 대해 분석하였다.

• 성인간호학회지
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• 제15권1호
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• pp.94-104
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• 2003

Purpose: This study was performed to identify the factors which affected exercise and the perceived exercise behaviors in women according to Q-methodology and to provide basic strategies for health promotion of middle-aged women in Korea. Method: Q-methodology provides a scientific method for identifying perception structures that exist within certain individuals or groups. Thirty subjects in Seoul, Incheon, Chung-buk classified 35 selected Q-statements in to 9 points standard. The collected data was analyzed by using a QUANL pc program. Result: Principal component analysis identified 3 types of exercise behavior of middle-aged women in Korea and named by the researcher. They are called persistent activity preference type, living-exercise preference type, exercise mania type. In persistent activity preference type, the middle-aged women thought activity was very helpful to achieving health and releasing stress or fatigue. Also, they recognized the relationship between physical health and psychological health. In living-exercise preference type, the middle-aged women preferred maintaining stability or nonactivity to intended exercise or activity for health. In exercise mania type, the middle-aged women thought there was no other way to keep her health than to exercise. Conclusion: The findings of this study will provide the health care provider including nurse with useful information. It's very important to offer appropriate exercise intervention to the middle-aged women of each type by taking into consideration the characteristics of individual types.

• 한국엔터테인먼트산업학회논문지
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• 제15권5호
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• pp.175-188
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• 2021

본 연구는 2019년 청소년건강행태조사 자료를 이용하여 비수도권과 수도권 청소년들의 정신건강이 평생 음주, 평생 흡연경험에 미치는 영향을 파악해 보고자 하였다. 연구대상은 중학교 400개교, 고등학교 400개교 총 800개교의 60,100명의 대상자 가운데 조사에 참여한 전체 청소년 57,303명을 대상으로 하였으며, 이 중 중학생이 29,384명, 고등학생이 27,919명으로 선정하였다. 연구결과 비수도권의 경우, 평생 음주, 평생 흡연 경험에 유의한 영향을 미치는 정신 건강은 주관적 건강인지, 스트레스인지, 피로회복정도, 슬픔과 절망감 경험, 자살생각, 자살계획, 자살시도가 유의한 것으로 나타났다. 수도권의 경우, 평생 음주, 평생 흡연 경험에 유의한 영향을 미치는 정신 건강은 스트레스인지, 피로회복정도, 슬픔과 절망감 경험, 자살생각, 자살시도는 유의한 것으로 나타났다. 이러한 결과를 바탕으로 청소년들의 음주문제가 정신건강 특성에 영향을 미치는 것으로 보아 수도권과 비수도권 청소년들의 지역별 정신 건강요인을 고려한 방향설정과 교육프로그램의 재평가를 통해 보다 효과적인 청소년들의 음주예방을 위한 중재 및 교육프로그램 개발을 위한 노력이 필요하다.