• Special Issue of the Society of Naval Architects of Korea
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• 2005.06a
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• pp.192-197
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• 2005

A welding bead height is closely related to the efficiency of welding work, and the height of 3mm is used in the conventional practice of butt welding. in the present paper, the modification of bead height from 3mm to 6mm is considered to increase the efficiency and work productivity of butt welding on bottom plate (of BONGA FPSO actually built in SHI shipyard). Therefore, fatigue analysis has been carried out using simplified method based on the DNV Rules. It is found that the minimum fatigue life is about 594 years and the butt welding details with 6mm bead height has sufficient strength and resistance against fatigue.

• Korean Journal of Adult Nursing
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• v.29 no.2
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• pp.190-199
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• 2017

Purpose: The purpose of this study was to investigate the differences in sleep, fatigue, and neurocognitive function between shift nurses and non-shift nurses. Methods: A cross-sectional descriptive study design was used. A total of 100 nurses participated in the study. 50 were shift nurses and the remaining 50 were non-shift nurses. The Pittsburgh Sleep Quality Index, Fatigue Severity Scale, and a computerized neurocognitive function test (CNS Vital Signs-VS4) were administered to the subjects to assess verbal and visual memory, processing speed, reaction time, and simple attention. After the last night shift, the shift nurse conducted the study at around 8:00 am and the non-shift nurse participated after work. Results: Compared to non-shift nurses, shift nurses had a significantly lower sleep quality (p=.002) and higher fatigue (p=.001) and achieved significantly lower scores on verbal memory (p=.001), processing speed (p=.003), and reaction time (p=.018). There were significant correlations between sleep quality and processing speed (p=.042), and reaction time (p=.015) of shift nurses who were bad sleepers. Conclusion: This study findings suggest shift work could interfere with cognitive function. Personal and organizational programs should be developed to support their sleep and neurocognitive function.

• Women's Health Nursing
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• v.4 no.3
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• pp.429-440
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• 1998

A survey was conducted to examine the fatigue and the related factors in pregnancy. 426 pregnant women were recruited from antenatal clinic at 8 hospital from November 1, 1997 to January 1, 1998. Fatigue was measured by the Modification of the Fatigue Symptoms Checklist(MFSC) developed by the Industrial Fatigue Research Committee of the Japanese Association of Industrial health(Yoshitake, 1978). The MFSC consisted of 34 items with 4-point Likert scale. Minor discomfort during pregnancy was measured using a 14-item checklist with 4-point Likert scale. The data were analyzed by percentage, t-test, ANOVA and Pearson correlation. The major findings of study were as follows : 1. The average fatigue score during pregnacy was 63.02 and the average minor discomfort score was 26.92. 2. The fatigue score of nullipara was significantly lower than that of mutipara. There was a significant difference of fatigue score between pregnant women with conjugal family and those with extended family. The fatigue score during 1st trimester was the highest in comparison with that of 2nd and 3rd trimester of pregnancy. 3. The fatigue score of pregnant women who worked for house-keeping only was significantly lower than that of pregnant women who worked partially or did not work for house-keeping. 4. There were significant correlations among each type of measure of fatigue and discomfort. Fatigue was the most common symptom during pregnancy and related to type of family, house-keeping work, and parity. Nursing intervention such as self-car, relaxation, and nutrition would be developed to manage fatigue problem in pregnancy.

• Korean Journal of Adult Nursing
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• v.20 no.6
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• pp.941-949
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• 2008

Purpose: This study was conducted to describe the effects of aroma inhalation on sleep and fatigue in night shift nurses. Methods: The research design was one group pre-posttest design. The subjects were 17 night shift nurses who work at neurosurgery intensive care unit of K hospital of C university in Seoul. During three consequent night shifts, the participants were worn the Actigraph to measure the sleep pattern on their wrist since their first night shift work. The quality of sleep and fatigue was measured by survey when they awoke at 6 pm after second night shift work. And these measures were repeated during the night shifts in second and third week. Aroma inhalation was applied before going to bed after finishing each night shift work during second and third week. SPSS 12.0 program was used for data analysis. Results: There were no statistically significant differences in sleep latency and total sleeping time. However, significant differences were found in the sleep efficiency, awakening number, sleep quality, subjective symptom and intensity of fatigue. Conclusion: These results showed that aroma inhalation had positive effects on the pattern and quality of sleep and reducing fatigue in night shift nurses.

• Journal of the Korean Society of Safety
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• v.35 no.5
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• pp.1-8
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• 2020

Mobile elevating work platforms (MEWPs) consist of a work platform, extending structure, and chassis, and are used to move persons to working positions. MEWPs are useful but are composed of pieces of equipment, and accidents do occur owing to equipment defects. Among these defects, accidents caused by the fracture of bolts fixed to the extension structure and swing system are increasing. This paper presents a failure analysis of the fixing bolts of MEWP. Standard procedure for failure analysis was employed in this investigation. Visual inspection, chemical analysis, tensile strength measurement, microstructural characterization, fractography analysis by Optical Microscope(OM) and Scanning Electron Microscopy(SEM), and finite element analysis (FEA) were used to analyze the failure of the fixing bolts. Using this failure analysis approach, we found the root cause of failure and proposed a means for solving this type of failure in the future. First, the chemical composition of the fixing bolt is obtained by a spectroscopy chemical analysis method, which determined that the chemical composition matched the required standard. The tensile test showed that the tensile and yield strengths were within the required capacity. The stress analysis was carried out at five different boom angles, and it was determined that the fixing bolt of MEWP can withstand the loads at all the boom angles. The outcomes of the fatigue analysis revealed that the fixing bolt fails before reaching the design requirements. The results of the fatigue analysis showed primarily that the failure of the fixing bolt was due to fatigue. A visual inspection of the fractured section of the fixing bolt also confirmed the fatigue failure. We propose a method to prevent failure of the fixing bolt of the MEWP from four different standpoints: the manufacturer, safety certification authority, safety inspection agency, and owner.

• Journal of Environmental Health Sciences
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• v.30 no.3
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• pp.272-282
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• 2004

Stress is a primary health promotion issue in worksite research because psychological distress is closely related not only to workers　 health status but also to their job performance. This study identified the work environment and work condition factors affecting workers　 stress symptoms among the Korean manufacturing factory workers. A total of 7,818 factory workers employed in 1,562 manufacturing companies participated in the Korean nation-wide occupational health survey conducted by the Korean Occupational Safety and Health Agency in 2003. Participants were selected by the stratified proportional sampling process by standardized industry classification, company size, and locations. Trained interviewers visited the target companies and interviewed the factory workers randomly selected in each company. Work environments included physical work environments (temperature, noise, hazardous organic compounds, and so on) and psychological work environments (job demands, job control, and social support at work), and work conditions included daily working hour, rest time, and so on. Men were 71.5% and the mean age was 34.0 years old. The average working period in the present company was 6.9 years. The average stress score was 26.2 under the perfect score, 50, which means the moderate level of stress. Perceived stress had significant correlations with young age, poor physical work environment, high fatigue, bad perceived health status, and high job demands in Pearson's simple correlation analysis. Perceived health status and perceived fatigue explained 21% variance of stress symptoms and the work environment factor explained 4.8% of that; however, work condition did not have the sufficient effect. In particular, psychosocial work environment variables (job demand, job control, and social support at work) had a clear effect on stress symptoms rather than the physical work environments. Poor perceived health status, severe perceived fatigue, poor physical work environment, high job demands, low social support, heavy alcohol consumption and little exercise were significantly related to high stress symptoms in the Korean manufacturing workers.

• PNF and Movement
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• v.19 no.2
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• pp.225-231
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• 2021

Purpose: This study was conducted to investigate the type of physical therapist response work and its intensity, along with the prolonged prevalence of COVID-19, to determine the impact on physical therapists' occupational stress and occupational burnout. Methods: An online survey was conducted with 118 physiotherapists and collected the participants' gender, final educational background, clinical work experience, workplace type, additional workload, and fatigue associated with COVID-19. After excluding one participant who submitted an incomplete questionnaire, 117 respondents were included in the final data. Results: Additional COVID-19-related workloads and response reliability for fatigue, occupational burnout, and occupational stress were shown to have Cronbach's alpha measures of 0.76, 0.89, and 0.87, respectively. Groups who had experienced a new epidemic in the past showed higher fatigue levels (3.06±0.94) than those groups who had no such experience (2.49±0.84; p < 0.05). Correlation analysis of COVID-19 work fatigue and occupational burnout scales showed a positive correlation (r = 0.19; p < 0.05). The regression of occupational burnout and occupational stress showed a regression model of Y = 20.00+0.43X₁ (X₁: job stress; p< 0.05) and an explanatory power of 24.8% with an adj.R² = 0.25. Conclusion: Based on the results, it is suggested that various institutions, such as medical institutions, educational institutions, and physiotherapists' associations, should seek ways to manage and alleviate physiotherapists' stress.

• Transactions of Materials Processing
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• v.11 no.1
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• pp.61-68
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• 2002

The thermal shock and thermal fatigue test has been carried out to analyze the thermal characteristics of tool steels for hot forging and the effects of mechanical properties on this study have been investigated. The resistance to thermal shock is first of all a matter of good toughness and ductility. Therefore, a proper hot-work tool steel should be characterized by high fracture strength and high temperature toughness. Based on these results, some critical temperature($T_{fracture}$) at which fracture occur can be measured to characterize the thermal resistance of the materials. During thermal fatigue tests, the thermal fatigue cracks occur because of the repetitive heating and cooling of the die surface and the thermal fatigue damage was evaluated by analyzing different number of cycles to failure. The results showed that the resistance to thermal shock and thermal fatigue were found to be favoured by high hot tensile strength and high hot hardness, and thermal resistance of SKD61 was superior to that of ESC, SKT4 and this was caused by higher mechanical properties of SKD61.

• Journal of the Korean Home Economics Association
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• v.27 no.1
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• pp.47-58
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• 1989

This study was undertaken to investigate whether the stress caused by day/night shifts on industrial workers can be affected through nutritional status. A sample of 573 female industrial workers, aged 17 through 23 years, from 4 different industries (2 in normal, 2 in 3 shift work pattern) were surveyed by questionaire examining their nutritional status, food intake, dietary habit, sleep complaint, performance of digestive organs, and degree of fatigue. Shift workers were surveyed during night work. The results are summarized as follows: 1. Sleep complaints and degree of fatigue in shift workers were higher than normal workers, whereas the performance of digestive organs were as lower than normal workers. These results showed that shift workers were more stressed than normal workers. 2. The workers who were surveyed were all poor in nutritional status. The intakes of calorie, protein, Ca, riboflavin, and ascorbic acid were lower than Korean Recommanded Dietary Allowences (RDA). Dietary habit of the shift workers was irregular. 3. There was a negative correlation between nutritional status and degrss of fatigue. The intakes of energy nutrients, ascorbic acid, and niain were significantly related to the degree of fatigue in which protein intake was found to be most influential. Among workers with the same level of protein intake, shift workers showed higher degree of fatigue. When the protein intake of shift workers was 100-125% of R.D.A., they showed the same degree of fatigue to the average normal workers.

• Journal of Korean Biological Nursing Science
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• v.7 no.2
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• pp.5-15
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• 2005

The purpose of this study was to compare the sleep and fatigue between groups with two shift and three shift nurses. A total of 14 nurses working in Neonatal Intensive Care Unit(NIC) were included with the seven for two shifts and the other seven for three shifts. Data were collected by Korean version of sleep tool(Oh et al., 1998) and fatigue symptom tool(Kim et al., 2001) and analyzed using SPSS PC 12.0. The results of the study were as follows: 1) There was statistically a significant difference in the number of total sleep hour and no difference in fatigue between groups. 2) There were no significant differences found in both sleep and fatigue by demographic characteristics between groups. 3) There were no correlations between sleep and fatigue in both groups. Through the further future studies, the findings of this study were expected to provide an opportunities for exploring the information on 2-shift nurses as well as 3-shift nurses and to offer the fundamental data on an arrangement of work force according to the types of shift work.