• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.6
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• pp.126-131
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• 1998

The influence of shot peening on the fatigue strength of SCM22 steel is investigated in this work. The shot peening process is applied to the heat treated specimens. Then, basic material properties and residual stresses are evaluated for specimens. Rotate bending and torsional fatigue tests are accomplished to investigate the effects of shot peening on the fatigue strength. experimental results show that the fatigue life was increased tremendously by shot peening. The compressive residual stress, which is induced by shot peening process, seems to be an important factor of increasing the fatigue strength.

• Journal of Industrial Technology
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• v.26 no.A
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• pp.69-73
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• 2006

Mach peening treatment is one of the various kinds of techniques to improve the fatigue properties. The mach peening process gives high-level work hardening and compressive residual stress near the surface layer, improving the fatigue strength. In addition, this treatment reduces slip bands that initiate the fatigue cracks near the surface. During impingement, a plastic indentation surrounded by a plastic zone is formed. Mach peening treatment characteristic is less energy consumption and is an environmental friendly processing methods that is not accompanied by pollution. It is machining process that can prevent fatigue fracture beforehand in structure using already as well as process of production. The test results showed that fatigue crack propagation delay appeared by drilling type 43%, mach peening type 110%.

• Women's Health Nursing
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• v.9 no.1
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• pp.61-69
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• 2003

Fatigue is a universally common word. The subject has been studied in different disciplines, but the basic concept of the term still remains unidentified. It becomes especially important for the medical communications between nurses and clients. Based on the framework outlined by Walker and Avant (1995), this analysis attempts to clarify and examine the symptoms of fatigue. The attributes of fatigue identified in this paper were exhaustion, weighted psychological burden, shortage in capacity or lack of energy, shortage incapacity(motivation and excitement), and imbalance of energy. Therefore, the definition of fatigue refers to a subjective feeling from various internal or external stresses. The consequences of fatigue bring reduced capacity and imbalance of energy. The symptoms show a homeostatic disability or shortage of capacity (physical, psychological, environmental and physiological factors). A precise understanding of "fatigue" will be utilized in defining the causes and measuring outcomes. Also, it will enhance the effective medical communications with client s and nurses. In conclusion, more work is needed to develop objective measurement and effect ivenursing intervention.

• Culinary science and hospitality research
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• v.14 no.3
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• pp.16-30
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• 2008

Rapid change of surroundings has been influencing the work environment for cooks, making it more convenient; however, there are still many difficulties to improve. Especially, cooks are exposed to lots of occupational diseases due to tension and pressure as well as noise, high temperature and humidity in their work place. This study examines cooks' operational exhaustion caused by cooking operation and cooking circumstances. The analyzed result shows the job fatigue related to the general features of the cooks(such as charged cooking part, types of engaged business, class of position, cooking career, and working hours). For example, pains on the neck, back, arms and wrist are mostly affected by the charged cooking parts. Effects related to the types of engaged business, backaches usually occurred in Catering, pains in shoulder from serving at hotels and eye-tiredness from meal serving. As for working hours, most of backaches occurred from over 13-hour-work, and pains in shoulder and eye-tiredness under 8-hour-work. Pains in legs, tiredness, and the change of weight do not have any relations withthe general features of the cooks statistically(p>0.05).

• Korean Journal of Occupational Health Nursing
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• v.20 no.3
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• pp.356-364
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• 2011

Purpose: This descriptive study was to examine the effect factors on health promotion lifestyle of shift work nurses. Methods: The 418 working nurses who completed questionnaires with consent were analysed. Results: The average level of health promotion lifestyle of shift work nurses was 2.21 and it was significantly lower than 2.36 of fixed work nurses. In shift work nurses, the highest health promotion lifestyle was personal relationship of 2.79 and the lowest was physical activity of 1.58. The young, shorter shift work duration, unmarried and general nurses were evaluated as not-healthy diet. The old, longer shift work duration and married showed less physical activity. Less self-efficacy and more job stress, depression, fatigue showed lower health promotion lifestyle. Conclusion: Self-efficacy on health behavior of shift work nurses was the most effective factor on all areas of health promotion. Therefore, we need to develop a health promotion program including self-efficacy encouragement. We suggest that this program be more effective when more precisely characterized according to age, marital status, shift work duration, job position, and psychological problems such as depression and fatigue.

• Korean Journal of Applied Biomechanics
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• v.24 no.1
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• pp.59-66
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• 2014

The purpose of this study was to investigate the effects of knee joint muscle fatigue and overweight on shock absorption during single-leg landing of adult women. Written informed consent forms, which were approved by the human subject research and review committee at Dong-A University, were provided to all subjects. The subjects who participated in this study were divided into 2 groups: a normal weight group and an overweight group, consisting of 15 young women each. Both the normal weight group and the overweight group showed that use soft landing and ankle dominant strategy. The peak vertical ground reaction force, the knee joint absorption power, and eccentric work done, as the increase of knee joint muscle fatigue level, showed a decrease. And the hip joint absorption power and eccentric work done, as the increase of weight, was less than the overweight group showed the normal weight group. In conclusion, the accumulation of the knee joint muscle fatigue and the increase of body weight may lead to an increased risk of injury during landing.

• Journal of Korean Academy of Nursing Administration
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• v.22 no.5
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• pp.471-479
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• 2016

Purpose: This study was conducted to evaluate the level of safety climate, fatigue, and safety performance and to identify the impact of safety climate and fatigue on the safety performance of operating room nurses. Methods: The study design was a descriptive survey. Participants were 174 operating room nurses from two general hospitals and two university hospitals in S and D cities. Three structurally designed questionnaires were used to evaluate their safety climate, fatigue, and safety performance. Collected data were analyzed using descriptive analysis, t-tests, ANOVAs, Pearson correlation coefficient, and stepwise multiple regression. Results: Safety performance of operating room nurses had a mean of 3.26 on a 5-point scale. 'Current department career'(${\beta}=.17$, p=.006) and 'safety climate (work-unit contribution) (${\beta}=.63$, p<.001) accounted for 39% of the variance in operating room nurses' safety performance. Conclusion: Findings indicate that work-unit contribution towards safety climate is an important factor in increasing operating room nurses' safety performance. Therefore, it is essential to find motivational properties consistent with the characteristics of the operating room environment.

• Structural Engineering and Mechanics
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• v.53 no.2
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• pp.325-336
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• 2015

This paper presents a study based on the damage due to the fatigue life of thrust ball bearings using vibratory analysis. The main contribution of this work lies in establishing a relation between modal damping and the rolling contact fatigue damage of the thrust ball bearing. Time domain signals and frequency spectra are extracted from both static and dynamic experiments. The first part of this research consists in measuring the damping of damaged thrust ball bearings using impact hammer characterization tests. In a second part, indented components representing spalled bearings are studied to determine the evolution of damping values in real-time vibration spectra using the random decrement method. Dynamic results, in good agreement with static tests, show that damping varies depending on the component's damage state. Therefore, the method detailed in this work will offer a possible technique to estimate the thrust ball bearing fatigue damage variation in presence of spalling.

• Proceedings of the Korea Contents Association Conference
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• 2017.05a
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• pp.257-258
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• 2017

Modern society tends to bring excessive labor to people and, therefore, further health management is required. In this paper, by using the clustering technique, one of machine learning methods, we try to bring out the measure of fatigue from heart rate (HR) variation during daytime work, helping people to get high-quality of healthy and calm life.

• Korean Journal of Health Education and Promotion
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• v.24 no.3
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• pp.61-71
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• 2007

Objectives: The research was conducted to evaluate the socio-demographic, life style and work related factors of stress and fatigue, and correlation between them in the white collar workers. Methods: This study was targeted on white collar workers of medium-sized company in Kimhae city including 249 people; 167 of males, 82 of females. The data was collected by structured questionnaires and analyzed using t-test, ANOVA, Pearson correlation and stepwise multiple regression with SPSS 12.0. Result: Both stress and fatigue levels were higher for female of gender, 20s of age, single of marital status in socio-demographic factors. The stress level was higher for current smokers and lower frequency of regular exercise per week, and both stress and fatigue levels were higher for unsatisfied sleeping in lifestyle factors. The stress level was lower for 5-day workweek system and experience of downsizing, and both stress and fatigue levels were higher far lower period of employment in work related factors. The correlation coefficient(r) between stress and fatigue level was 0.578, which was highly statistically significant. According to stepwise multiple regression analysis, factors affecting stress were unsatisfied sleeping, female and lower frequency of regular exercise per week, and those affecting fatigue were younger age and unsatisfied sleeping. Conclusion: This study provided strong support for associations between stress and fatigue, and we suggest that modifiable factors such as regular exercise and satisfied sleeping would be important for white collar workers to reduce their stress and fatigue.