• Korean Journal of Occupational Health Nursing
• /
• v.7 no.2
• /
• pp.155-163
• /
• 1998

In order to investigate the effects of rotating shift work on the subjective characteristics of sleep and mental depression questionnaire survey was carried out on 405 shift workers and 153 nonshift workers who were nurses employed. in three university hospital. The questionnaire forms used in this study were the self rating depression scale(SDS) and circadian type questionnaire(CTQ) factor R(rigidity/flexbility of sleeping habit) and factor V(inability/ability to overcome drowsiness). The results were as follows ; 1. Mean score of CTQ R in shift workers was significantly lower than that in nonshift workers, however, no significant difference in CTQ V was observed between two groups. 2. Mean score of SDS was significantly higher in shift workers(44.1) than in nonshift workers(39.8). 3. Mean self rating depression scale scores of pervasive affect, physiologic equivalents and psychological equivalents were significantly higher in shift workers than in nonshift workers. 4. In shift worker, mean SDS score was the highest in confusion and followed by diurnal variation, retardation, and indeciveness in the descending order. In nonshift worker, that score was the highest in decreased libido and followed by confusion, and indeciveness in the descending order. 5. Circadian type questionnaire scores was significantly and negatively correlated with significantly and negatively correlating with Self-rating depression scale scores(r=-0.473).

• 한국신재생에너지학회:학술대회논문집
• /
• 2008.10a
• /
• pp.361-364
• /
• 2008

In this paper, several fields for improving shift quality and mode conversion quality are presented and considered. For a series type hybrid vehicle, improving mode conversion quality is important because it changes its speed with its own motors. A parallel type hybrid vehicle usually has AT or AMT, and its motor and engine can work independently. Therefore, improving both of two qualities is equally important in this case. For a power split type hybrid vehicle, improving mode conversion quality is more important due to the existence of planetary gears which change vehicle's speed.

• Korean Management Science Review
• /
• v.20 no.2
• /
• pp.33-43
• /
• 2003

In this paper we applied dynamic programming to determining work schedule type. In dynamic programming formulation, each day during a planning horizon represents a stage for which a decision is made. The alternatives are given by work schedule types that combine regular time, overtime, additional shift, and so on. In this case, their associated return function is labor cost. The state is defined as the amount of work time allocated to stage 1, stage 2,…, and current stage. A case study for a real manufacturing company was performed to apply dynamic programming to scheduling daily work hours during a week. The case study showed that total cost of our solution derived from dynamic programming decreased by about 6％ as compared with the solution obtained from the previous method.

• Journal of Korean Academy of Nursing
• /
• v.40 no.5
• /
• pp.650-661
• /
• 2010

Purpose: Work-related anxiety and depression are frequent work-related mental health problems. In this study the relationship between workplace violence and work-related anxiety and/or depression among Korean employees was evaluated. Methods: Data were obtained from the Korean Working Condition Survey of 2006. Participants were 9,094 Korean workers aged 15-64 yr. Multiple logistic regression using SAS version 9.1 was used. Results: The incidence of work-related anxiety, work-related depression and workplace violence were 4.5%, 3.5%, and 1.8% respectively. When personal and occupational risk factors were adjusted, workplace violence was significantly associated with work-related anxiety and depression (OR for anxiety: 4.07, CI: 2.62-6.34; OR for depression: 4.60, CI: 2.92-7.25). Work-related anxiety was significantly related to type of employment, working period at present workplace, work time, shift work, job demand, and social support from superiors. Factors influencing work-related depression were gender, education, alcohol consumption, company size, type of employment, working period at present workplace, work time, shift work, and job demand. Conclusion: To promote psychological health in workers there is a need to develop work-related anxiety and depression prevention programs and to decrease in workplace violence. In developing these programs, consideration should be given to personal factors, working conditions, and psychosocial working environments.

• Journal of Korean Academy of Nursing
• /
• v.39 no.4
• /
• pp.549-561
• /
• 2009

Purpose: Work-related stress and risk factors among Korean employees were identified in this study. Methods: Data were obtained from employees aged 20 to 64 using the Korean Working Conditions Survey 2006 (KWCS). Multiple logistic regression analysis using SAS version 9.1 was performed to examine risk factors of work-related stress by gender. Results: The age-adjusted prevalence of work-related stress among male and female employees was 18.4% and 15.1% respectively. After adjustments for multiple variables among both male and female employees, there was a significant relationship between work-related stress and risk factors including education, company size, work time, ergonomic risks, biological chemical risks, and job demands. The significant variables for male employees were housework load, occupational class, and shift work, and for female employees, type of employment. Conclusion: There is a need to develop and support intensive stress management programs nationally giving consideration to work-related stress associated with working time, physical working environment, and job demands. Based on gender specific approaches, for male employes, stress management programs should be developed with consideration being given to occupational class and shift work. For stress management programs for female employees, consideration needs to be given to permanent employment status, specifically those in small companies.

• Korean Journal of Psychosomatic Medicine
• /
• v.22 no.2
• /
• pp.79-86
• /
• 2014

Objectives : Shift work disorder occurs when you have difficulties adjusting to a work schedule that takes place during a time which most people sleep. Some people may have diverse psychosomatic symptoms, such as sleep problems, depression, anxiety, and headaches even after the shift work schedule ends. The aims of this study are to compare difference of psychosomatic symptoms between rotating shift and daytime working nurse groups. Methods : Volunteer nurses working in a general hospital were recruited in a general hospital. We collected sociodemographic data. We used questionnaires for headache type, headache frequency, and VAS(Visual Analog Scale) for headache intensity, BDI(Beck depression Inventory) and GSAQ(Global Sleep Assessment Questionnaire). We used Mann-Whitney test and Chi-square test for hypothesis testing. Results : Data collected from 84 women nurses. Rotating shift(N=37) working nurses showed younger, more unmarried, and shorter work periods than daytime working nurses (N=47). Also rotating shift group showed more problems of headache, insomnia, excessive daytime sleepiness, depression and anxiety than daytime group. The above results were statistically significant. Conclusions : The rotating shift work women nurses produced more headache, insomnia, excessive daytime sleepiness, depression, and anxiety than daytime working ones.

• Proceedings of the Safety Management and Science Conference
• /
• 2008.11a
• /
• pp.303-316
• /
• 2008

For the past 25 years, Korean semiconductor has experienced enormous growth to be the highest production country in the world. Semiconductor industry is very time sensitive and driven by technology and process, and requires 24-hour full operation. The environment includes many different types of equipment, utilities, different gases and toxic chemicals as well as high voltage electricity. We have performed a survey with 3-shift engineers and workers in one line. The content of the questionnaire was about the correlation between fatigue and performance shaping factor (work type and work ability), and as a result we were able to deduce the correlation, p-value and the pattern of scatter plot. The shape of the model was made of 4 blocks for fatigue, 5 blocks for work type and 5 blocks for work ability, i. e. 14 blocks in total. As a conclusion to this findings, there was a correlation between fatigue and work type and work ability specifically in semiconductor industry, and we need some effort to reduce this.

• Korean Journal of Occupational Health Nursing
• /
• v.16 no.1
• /
• pp.37-47
• /
• 2007

Purpose: To find out the relationship between the shift work, and disrupted sleep and consequent fatigue symptoms. Methods: The questionnaires were given to 345 nurses of 4 hospitals with over 400 beds in Daejeon. Results: The shift workers showed worse subjective quality of sleep than the daytime workers, and had significantly higher frequency of "cannot get to sleep within 30 minutes", "wake up in the middle of the night" and "wake up in the early morning". The shift workers had significantly higher scores of subjective symptoms of fatigue than the daytime workers, and the fatigue was found to be the mental type. The subjective symptoms of fatigue scores were significantly higher in the group who had "cannot get to sleep within 30 minutes", "wake up in the middle of the night" and "wake up in the early morning". Conclusion: The study results indicated that the shift workers had the higher level of subjective symptoms of physical fatigue as well as the worse quality of sleep than the daytime workers. It is speculated that the factors attributable to the poor quality of sleep or sleep induction disorders of nurses of hospitals could be due in major part to adaptational difficulties resulting from frequent night shifts.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.6
• /
• pp.546-559
• /
• 2016

This study was conducted to analyze the relationship between sleep quality, stress response, physical activity and sleep hygiene in shift work nurses and identify factors influencing sleep quality. The participants were 168 shift nurses from university hospitals and general hospitals located in C city, Gyeongnam. Data were collected from March 25 to 31, 2016. The study instrument use to the Pittsburgh Sleep Quality Index, Stress Response Inventory, Korean version of the International Physical Activity Questionnaire Short Form and Sleep Hygiene Scale. Date were analyzed by frequency, t-test, ANOVA, Pearson's correlation and hierarchical multiple regression using SPSS/win18.0. The sleep quality index was 7.35 (range 0-21), stress response was 2.20 (range 1-5), physical activity was 3986MET-min/week, and sleep hygiene was 2.73 (range 1-6 points). There were significant differences in sleep quality according to shift work experience, health status and circadian rhythm type. Factors influencing sleep quality included shift work experience, sleep hygiene, stress response and physical activity, which together explained 40% of the total variance of sleep quality. Therefore, it is recommended that sleep hygiene education be implemented as a strategy to reduce stress response, and that shift work nurses engage in a moderate level of physical activity to improve their sleep quality.

• Journal of Korean Academy of Nursing
• /
• v.21 no.2
• /
• pp.129-149
• /
• 1991

Circadian rhythm is entrained in the 24-hour time interval by periodic factors in the environment, known as zeitgeber. But most rotating work schedules are outside the range of the entrainment of the pacemaker timing the human circadian sleep - wake cycle. It has been postulated that physiological and emotional disturbances occur in most human functions when the circadian rhythm is disturbed. So application of circadian principles to the design of shift schedules can aid in maintaining the temporal integrity of the circadian system and thereby minimize for the shift worker any detrimental consequences of circadian disruption. This study was a quasi-experimental study to test the effect of shift intervals for the clinical nurse on the circadian rhythm. Twenty nurses newly employed in general units of two hospitals were selected as an experimental group and twelve college nursing students as a control group. Both groups were selected according to an established criteria using a purposive sampling technique. Ten subjects were assigned to a weekly shift group and another ten to a biweekly shift group engaged in a semi -continuous shift schedule(sunday off) with a backward direction, that is, morning -evening - night shift. The control group worked a morning shift for 42 days. Oral temperature rhythm, waking tim, sleep - wake cycle, fatigue, and mental performance were measured during the experimental period. The data collection period was from April 30, 1990 to June 10, 1990. MANOVA, paired t-test, ANOVA, and Student Newman Keuls method were used for statistical analysis. The results are summarized as follows. 1. Phase delay in the acrophase of temperature rhythm was shown according to the backward rotating shift. A complete adaptation to work on the night shift was achieved between the sixth and ninth day of the night shift. 2. There was no difference in either waking time or sleep- wake cycle according to the duration of the working day for every shift group. Significant difference was found in the waking time and the sleep -wake cycle for subjects on the morning, evening, and night shift in both of the shift groups(weekly shift group : λ＝0.121, p＜0.01, λ＝0.112, p＜0.01, biweekly shift group : λ＝0.116, p＜0.01, λ＝0.084, p＜0.01). 3. There was no difference in fatigue between the first working day and the last working day for the control group and for the biweekly shift group. In the weekly shift group, physical fatigue was significantly different for the first day and the sixth day of the night shift(t＝-2.28, p＜0.05). Physical fatigue and total fatigue on the first day of the night shift showed a significant difference among the control group, the weekly shift group, and the biweekly shift group(F＝5.79, p＜0.01, F＝4.56, p＜0.05). There was a significant difference between the shift groups and the control group(p＜0.05), Physical fatigue, neurosensory fatigue and total fatigue on the last day of the night shift showed a significant difference among the control group, the weekly shift group, and the biweekly shift group(F＝12.65, p＜0.01, F＝7.77, p＜0.01, F＝9.68, p＜0.01). There was a significant difference between the shift groups and the control group(p＜0.05). 4. No difference in mental performance was seen between the first day and the last day of work in each case. An arithmatic test on the first day of the night shift revealed a significant difference among the control group, the weekly shift group, and the biweekly shift group(F＝3.79, p＜0.05). There was a significant difference between the shift groups and the control group(p＜0.05) . The digital symbol substitution test and the arithmetic test on the last day of the night shift showed a significant difference among the control group, the weekly shift group, and the biweekly shift group(F＝3.68, p＜0.05, F＝5.55, p＜0.01), and both showed a significant difference between the shift groups and the control group(p＜0.05). Accordingly, this study showed that during night duty, the waking time, sleep- wake cycle, and fatigue increased and mental performance decreased compared with morning and evening duty. It was also found that the weekly shift group had a higher fatigue score on the sixth day of night duty as compared to the -first day, but the waking time, sleep- wake cycle, and mental performance revealed no difference for the duration of the night duty or between shift groups, and complete adaptation of temperature rhythm was achieved between the sixth and ninth day of night duty. It is possible to conclude from these results that for intermediate circadian type in a healthy young woman, a biweekly shift system is more compatible with the circadian timing system than weekly shift system.