• 중환자간호학회지
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• 제13권2호
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• pp.1-11
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• 2020

Purpose : The aim of this study was to compare shift satisfaction, sleep, fatigue, quality of life (QOL), and patient safety incidents between a newly implemented two-shift system and a traditional three-shift system. Methods : A total of 127 intensive care unit nurses (48 two-shift nurses and 79 three-shift nurses) working in a tertiary hospital in Seoul were recruited from January 1, 2017, to March 31, 2017. They completed a self-reported questionnaire about their work hours, shift satisfaction, sleep patterns, sleep quality, fatigue, QOL, and patient safety incidents in the past 2 weeks. Data were analyzed using SPSS version 23.0. Results : The two-shift group showed higher shift satisfaction scores compared with the three-shift group (6.93 vs. 4.37, p<.001). Sleep latency was shorter and sleep quality was better in the two-shift group compared with the three-shift group. There were no significant differences in other sleep parameters, fatigue, QOL, and patient safety incidents between the two groups. Conclusion : Although a two-shift system did not improve nurses' fatigue or QOL in this study, it may effectively serve as an alternative shift-work system that can increase sleep quality and shift satisfaction without increasing patient safety incidents.

• 한국화재소방학회논문지
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• 제28권2호
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• pp.98-104
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• 2014

소방공무원의 열악한 근무조건을 개선하기 위해서 2004. 6. 1. 소방 방재청 출범과 함께 3교대 근무체제가 제시되었다. 그러나 차일피일 미루어 오다 2008. 12. 행안부장관이 2012년까지 3교대 전면시행을 보고하면서 이듬해 2009년부터 3교대 근무가 시범 실시되었고, 이후 2013년 6월 현재 약 97%의 시행률을 보이고 있지만, 지방재정 열악 등으로 2014년에 완료되는 것으로 알려지고 있다. 한편, 소방공무원 3교대 근무형태에 관한 국내연구는 거의 전무한 실정으로 아주 초보적이고 유치한 수준으로 이제 시작에 불과한 단계라 할 수 있다. 따라서 본 연구는 그동안 시행해 오고 있는 3교대 근무 시행의 문제점과 선결과제 등을 살펴보고, 향후 3교대 근무제의 실효성 확보를 위한 몇 가지 정책적 제언을 하는데 그 목적이 있다.

• 대한인간공학회지
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• 제29권3호
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• pp.337-345
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• 2010

The purpose of this study was to investigate the effects of sleep/wake behavior for shiftwork in air traffic controllers (ATCs) using wrist actigraph for ten workers on a continuous full-day three-team three-shift system of forward rotation including on-duty and off-duty periods. The wrist actigraph data were recorded for three days (one shift cycle) for each subject. The mean activity counts during an on-duty period progressively increased from the night, the swing, to the morning shifts. The doze length during on-duty periods showed decreases in the morning and swing shifts as compared to the night shift. Total sleep time (TST) and sleep efficiency (SE) during off-duty periods increased in the morning-1 and swing-night shift compared to the morning-2 shift. Finally, I discussed the role of doze-taking during the burden on night shift ATCs.

• Annals of Occupational and Environmental Medicine
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• 제35권
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• pp.14.1-14.10
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• 2023

Background: Shift work is known to cause changes in the circadian rhythm of the human body and adversely affect not only physical health but also mental health. Some studies have demonstrated the correlation between shift work and thyroid stimulating hormone (TSH), a hormone that changes according to the diurnal rhythm, but few studies have reported the different TSH levels according to the shift work type. This study aimed to investigate changes in TSH according to the shift work type. Methods: This study included 1,318 female workers who had a medical checkup at a university hospital in Changwon from 2015 to 2019. Shift work types were classified as non-shift work, regular 2 shifts, and irregular three shifts, and a TSH ≥ 4.2 mIU/L was defined as abnormal. A general linear model (GLM) was used to compare the TSH levels and the risk of subclinical hypothyroidism in each year, and a binary logistic analysis was performed using a generalized estimation equation (GEE) to compare the risk of subclinical hypothyroidism over the 5-year period. Results: Of the 1,318 participants included in this study, 363, 711, and 244 were non-shift, two-shift, and irregular three-shift workers, respectively. In the GEE analysis, after adjusting for age, body mass index, smoking, and alcohol consumption, the odds ratios (ORs) were 1.81 (95% confidence interval [CI]: 1.15-2.86; p = 0.011) in 2 shifts and 2.02 (95% CI: 1.23-3.32; p = 0.006) in irregular three shifts, compared to non-shift. Conclusions: Our results showed that shift work had a higher risk of subclinical hypothyroidism than non-shift work and that there was a significant difference in the risk of subclinical hypothyroidism according to the shift work type. These findings suggest that the shift work type can be considered in future thyroid function tests and evaluations.

• 새물리
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• 제68권12호
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• pp.1331-1337
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• 2018

We present a three-parameter phase shift model whose form is the same as that of Coulombmodified Glauber model obtained from Gaussian nuclear densities. This model is applied to the $^6Li+^{12}C$ and the $^6Li+^{28}Si$ elastic scatterings at $E_{lab}=318MeV$. The calculated differential cross sections provide quite a satisfactory account of the experimental data. The diffractive oscillatory structures observed at forward angles can be explained as being due to the strong interference between the near-side and the far-side scattering amplitudes. The optical potentials for two systems are predicted by using the method of inversion. The calculated inversion potentials are found to be in fairly good agreements with the results determined from the optical model analysis in the surface regions around the strong absorption radius. We also investigate the effects of parameters in the three-parameter phase shift model on the elastic scattering cross sections.

• 한국전자통신학회논문지
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• 제9권8호
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• pp.861-866
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• 2014

본 연구에서는 시간영역 위상잡음 이론의 기초가 되는 기존 3가지 위상편이 모델의 모델링 정확도를 평가한다. 평가를 위해 간단한 2차원 오실레이터의 위상편이 임펄스열 응답을 이 3가지 위상편이 모델이 얼마나 정확하게 모델링 하는지를 조사한다. 평가 결과, 5가지 임펄스열 입력에 대해서 오실레이터의 위상편이 임펄스열 응답을 가장 정확하게 반영하는 모델은 Kaertner 모델이었고 가장 부정확하게 모델링하는 모델은 PP 모델이었다.

• International Journal of Advanced Culture Technology
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• 제12권3호
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• pp.114-123
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• 2024

The purpose of this study is to identify the mediating effect of social support in the relationship between job stress and stress coping strategies among male workers on a three-shift system. The subjects of the study were 146 male workers working in manufacturing companies with more than 500 employees located in C City, Chungbuk Province, who understood the purpose of the study and agreed to participate. The collected data were analyzed using frequency and percentage, descriptive statistics, Pearson Correlation Coefficient, and multiple regression analysis. Job stress had a significant effect on the mediating variable, social support (β=.34, p<.001), and job stress had a significant effect on the dependent variable, stress coping strategies (β=.41, p<.001). When examining the effect of social support on stress coping strategies (β=.35, p<.001), social support was found to be a significant predictor of stress coping strategies. Therefore, social support plays a mediating role in the relationship between job stress and stress coping strategies among male workers on a three-shift system, and job stress and social support explained 27.4% of the variance in stress coping strategies. Thus, it is necessary to establish a psychological support system that can reduce job stress through active stress coping measures that consider the social support of male workers on a three-shift system.

• 대한산업공학회지
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• 제30권3호
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• pp.181-189
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• 2004

The purpose of this study was to investigate the effects of sleep/wake behavior for shift workers in the iron and steel industry using wrist actigraph for 59 male workers on a continuous full-day three-team three-shift system of backward rotation including on-duty and off-duty periods. The wrist actigraph data were recorded for 15 days (l shift cycle) for each subject. The sleep length at home during night shift decreased significantly as compared to the morning or evening shifts. The night shift nap length increased significantly in all sections as compared to the morning or evening shifts. The nap length in the Steel Manufacturing Process and Rolling Process during night shift decreased significantly as compared to the Machine Maintenance Section, the Forwarding of Products Section, and the Field Management Section. However, the sleep length at home while off-duty period increased significantly. The percentage of nap length during night shift in the Rolling Process, Steel Manufacture Process, and the other three types of jobs was 16.0%, 20.4%, and about 50.0%, respectively. The nap length during night shift for the above 50 year olds increased significantly as compared to the below 50 year olds. Finally, we discussed the role of nap-taking during the burden on night shift workers and the increased difficulty in continuing their job.

• 한국직업건강간호학회지
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• 제8권1호
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• pp.22-41
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• 1999

This study intended to analyze the health promoting behaviors, compare their factors according to the shift pattern of duties of women workers who were working in the industrial workplace and present basic data in planning systematic and effective programs of health promotion for three-shift system and day-duty. Using Quota Sampling, 219 women workers were selected as subjects from 5 workshops which had 50 settled workers up to 300 and 10 factories which had more than 300 located in Taegu and Kyung-Book Province. Data were collected by means of questionnaire from September 12 to September 30, 1998. As the instruments of the study were used Health Promotion Lifestyle Profile(HPLP) which was adapted and adjusted by Seo, Y. O. for health promoting behavior, the one developed by Moon, J. S. (1990) for health-belief, the one developed by Sherer et al.(1982) and then adapted by Oh, H. S. for self-efficacy, and the one developed by Park, J. W. (1985) for social support. The analysis of data were performed with Cronbach's ${\chi}^2$-test, t-test, ANCOVA, Kendal tau, Pearson correlation, Stepwise Multiple Regression test using SPSS program. The results of the study are as follows : 1. There was a significant difference in age(${\chi}^2=32.46$, p=0.000), career (${\chi}^2=18.47$, p=0.000), working day(t=-3.18, p=0.000) by the shift pattern of duties in terms of socio-demographic characteristics. 2. There was a statistically significant difference between the two groups on the health promoting behaviors (t=2,52, p=0.012). The score of three-shift group on health promoting behaviors was 2.27, showing that it was lower by .13 than that of day-duty group(2.40). 3. ANCOVA involving age, career and working day as covariables, which had revealed significant difference before, showed that health promoting behaviors by the shift patterns of duties was significantly different(F=4.88, p=0.028). 4. In consideration of variables that have an influence on health promoting behavior by the shift pattern of duties, social support occupied 19.4% of health promoting behavior in the three-shift group and 22.5% including the sense of self-efficacy. In the day-duty group, social support occupied 34.4% of health promoting behavior. 5. The score of three-shift group(2.94) was significantly lower than that of day-duty group(3.12) in the perceived benefit of health-belief(t= -3.29, p=0.001), while the score of three-shift group (2.48) was significantly higher than that of day-duty group(2.24) in the perceived barrier (t=4.22, p=0.000). In the sense of self-efficacy(t=-4.20, p=0.000), the score of three-shift group(3.24) was significantly lower than that of day-duty group(3.53) while in social support(t=-4.56, p=0.000) the one of three-shift group(2.64) was significantly lower than that of day-duty group(2.88). The suggestions are as follows on the basis of the results of this study : 1. It is required to develop health promoting program that takes the shift pattern of duties of women workers into consideration. In addition, there are special demands on developing nursing strategies for health promoting behavior of three-shift workers. 2. It is required to develop specific strategies for social support which is the most significant factor to the health promoting behavior for women workers. 3. It is necessary to develop some programs for improving the sense of self-efficacy, social support, and health-belief of three-shift workers. To achieve these tasks, industrial nurses should play an active role and improve the ability of self-health care of women workers.

• Journal of Electrical Engineering and Technology
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• 제12권5호
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• pp.1902-1915
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• 2017

This paper presents the evaluation of a three-phase three-level DC-DC converter which achieves the soft switching condition for all switches in the circuit and uses the phase-shift PWM strategy to adjust electric power at the output side. According to the analysis, the operation modes can be categorized into two cases: in the first case, where the phase shift angle is less than 120 degrees and in the second case, where the phase shift angle is more than 120 degrees. The outer switches of the circuit operate under ZVS condition and the inner switches operate under ZVZCS condition. It has been discovered that under ZCS condition of the inner switches, when the blocking capacitors decrease, they make the voltage across the blocking capacitor higher so the current reduce rapidly. A three-phase three-level DC-DC converter has a maximum efficiency of 93.5% when its load is of 5.7 kW. The results from the experiment have been compared to the results obtained by the $MATLAB^{(R)}$ simulator in order to confirm the validity of the proposed converter.