• 여성건강간호학회지
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• 제7권4호
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• pp.461-472
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• 2001

A study was done to identify mothers' perception of fatigue in postpartum period. Questionnaires were collected from 267 normal postpartum mothers in Korea from July to December 2000. The questionnaires used to measure mothers' fatigue were "Subjective Symptoms of Fatigue Test" designed by Research Committee of Industrial Fatigue in Hygienic Association of Japan Industry. The collected data were analyzed by SPSS-Win. The results revealed that The average fatigue score of subjects was 1.70; Physical fatigue had the highest value with a mean of 1.89, followed by psychological fatigue with a mean score of 1.62, neuro-sensory fatigue was rated lowest with a mean of 1.58. Sorting out the subjects fatigue level per a week during Sweeks, 6th week after postpartum had the highest value with a mean of 1.85. Degree of fatigue was also compared with the respect to the general characteristics of mothers: There were statistically significant differences according to mothers' job (t=-2.021, p=.046), sleeping time (t=2.771, p=.006), having a nap (t=-2.132, p=.034), baby character (F=3.089, p=.047), baby sex (t=-2.054, p=.041), having a person who help domestic affairs (t=2.292, p=.023). Therefore variable nursing intervention should be provided to alleviate the fatigue according to the postpartum period. Especially the nursing intervention program to alleviate the physical fatigue is needed.

• 대한기계학회논문집A
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• 제20권7호
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• pp.2159-2166
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• 1996

The stochastic properties of variation in fatigue crack growth are important in reliability and stability of structures. In this study,the stochastic model for the variation of fatigue crack growth rate was proposed in consideration of nonhomogeneity of materials. For this model, experiments were ocnducted on 7075-T6 aluminum alloy under the constant stress intensity factor range. The variation of fatigue crack growth rate was expressed by random variables Z and r based on the variation of material coefficients C and m in the paris-Erodogan's equation. The distribution of fatigue life with respect to the stress intensity factor range was evaluated by the stochastic Markov chain model based on the Paris-Erdogan's equation. The merit of proposed model is that only a small number of test are required to determine this this function, and fatigue crack growth life is easily predicted at the given stress intensity factor range.

• Steel and Composite Structures
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• 제22권2호
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• pp.353-368
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• 2016

This paper extends our recent work on the fatigue behavior of stud shear connectors in steel and recycled tyre rubber-filled concrete (RRFC) composite beams. A series of 16 fatigue push-out tests were conducted using a hydraulic servo testing machine. Three different recycled tyre rubber contents of concrete, 0%, 5% and 10%, were adopted as main variable parameters. Stress amplitudes and the diameters of studs were also taken into consideration in the tests. The results show that the fatigue lives of studs in 5% and 10% RRFC were 1.6 and 2.0 times greater of those in normal concrete, respectively. At the same time, the ultimate residual slips' values of stud increased in RRFC to highlight its better ductility. The average ultimate residual slip value of the studs was found to be equal to a quarter of studs' diameter. It had also been proved that stress amplitude was inversely proportional to the fatigue life of studs. Moreover, the fatigue lives of studs with large diameter were slightly shorter than those of smaller ones and using larger ones had the risk of tearing off the base metal. Finally, the comparison between test results and three national codes was discussed.

• 대한안전경영과학회지
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• 제16권3호
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• pp.35-44
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• 2014

This study empirically examines how much effect levels of fatigue and stress of a construction worker have on disaster risks from the perspective of human factors concerning construction disaster risks. To achieve the purpose of this study, a survey was conducted with respect to construction workers working at large construction sites within the metropolitan area. The retrieved survey data were analyzed by using the statistical software programs, SPSS 18.0 and AMOS 8.0. The results of this study do not definitively lead to the conclusion that the level of fatigue or stress of construction workers result in disaster risks. However, it does show that the results vary depending upon the individual approach and treatment of stress and fatigue. In particular, this study revealed that disaster risk levels could increase through unsafe behavior intentions which were established as a mediator variable. Also, with respect to unsafe behavior intentions of construction workers leading to disaster risks, when examining the results that the level of mental fatigue, occupational stress and social-psychological stress of construction workers had a greater significant effect than the level of physical fatigue, this study demonstrates the importance of psychological and mental issues that could be easily overlooked with respect manual labor workers.

• 기본간호학회지
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• 제25권1호
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• pp.58-67
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• 2018

Purpose: Fatigue and clinical practice stress can negatively influence nursing students. This study was done to examine of communication skill as mediating effect variable in the relationship between fatigue and stress during clinical practice. Methods: A cross-sectional study design was employed. Research participants were 124 nursing students from G city and J province. Data were collected from December 1, 2016 to January 30, 2017 using self-report questionnaires. Data were analyzed using Baron and Kenny method. Results: Fatigue had a significant negative correlation with communication skill (r=-.28, p=.001). Fatigue had a significant positive correlation with clinical practice stress (r=.39, p<.001). In addition, communication skill had a mediating effect in the relationship between fatigue and clinical practice stress. Conclusion: The findings of this study indicate that communication skill plays an important role in reducing clinical practice stress in nursing students. Therefore, in the field of nursing education, a program to improve the communication ability of nursing students should be developed and applied.

• 한국직업건강간호학회지
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• 제32권1호
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• pp.30-38
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• 2023

Purpose: This study aimed to investigate the effect of positive psychological capital, empathy ability, and stress coping style on psychiatric ward nurses' compassion fatigue. Methods: Data were collected using structured questionnaires for 140 psychiatric ward nurses. The data were analyzed using t-test, one-way ANOVA, and hierarchical regression. Results: The variable predictors of compassion fatigue were as follows: positive psychological capital (β=-.35, p<.001), empathy ability (β=.32, p<.001), and passive coping (β=.25, p=.004). These factors explained 27% of compassion fatigue, and psychological capital was found to have the greatest influence among these variables. Conclusion: Positive psychological capital, empathy ability, and passive coping are important factors influencing nurses' compassion fatigue in psychiatric wards. It is necessary to develop interventions and appropriate coping styles that strengthen positive psychological capital to prevent and reduce nurses' compassion fatigue in psychiatric wards. In addition, it is necessary to identify the required level of empathy ability to maintain a therapeutic relationship.

• 대한조선학회논문집
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• 제45권6호
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• pp.679-687
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• 2008

The fatigue life of ship structure under cyclic loading condition is made up of crack initiation and propagation stages. For a welding member in ship structure, the fatigue crack propagation life is more important than the fatigue crack initiation life. To calculate precisely the fatigue crack propagation life at the critical welding location, the knowledge of the residual stress sensitivity on the fatigue strength is necessary. In this study, thermo elastic-plastic analysis was conducted in order to examine the effect of residual stress on the fatigue crack propagation life. Also the fatigue crack propagation lives considering residual stress were calculated using fatigue crack growth code, AFGROW, on the basis of fracture mechanics. AFGROW is widely used for fatigue crack growth predictions under constant and variable amplitude loading. The reliability of AFGROW on the fatigue of ship structure was confirmed by the comparison of the estimated results with the fatigue propagation test results.

• 한국해양공학회지
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• 제6권1호
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• pp.131-139
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• 1992

The understanding and appllication of fatigue crack propagation mechanism in variable amplitude loading is very important for life prediction of the air travel structures. Particularly, the retardation and arrest behavior of fatigue crack propagation by single tension overloading is essential to the understanding and appllication of fatigue crack propagation mechanism in variable amplitude loading. Numerous studies of the retardation behavior have been performed, however investigations of the arrest behavior have not been enough yet. As for the arrest behavior, Willenborg had reported that the overload shut-off ratio $[R_{so}=(K_{OL})/K_{max})_{crack arrest}]$ had been the material constant, but recently several investigators have reported that the overload shut-off ratio depends upon the stress ratio. In this study, authors have investigated the effect of stress ratio on the threshold overload shut-off ratio to generate arrest of fatigue crack growth in high tensile aluminum alloy 7075-T735 which have used in material for air travel structures, It has been $-0.4\leqqR\leqq0.4$ till now, the region of stress ratio investigated. The threshold overload shut-off ratio has decreased as stress ratio has increased in overall region of -$-0.4\leqqR\leqq0.4$ and the linearity has been seen in this material. Moreover, the experimental equation between $R_{so}$ and R has been made; The relation has been $R_{so}=-R+2.6$.

• 대한기계학회논문집
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• 제16권8호
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• pp.1503-1512
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• 1992

본 연구에서는 열화평가 및 수명예측에 있어서 가장 중요한 문제로 대두되는 기계구조물의 사용시간과 부식 정도에 대한 관계 곡선을 규명하기 위하여 실험실의 가혹 환경하에서 부식을 시키면서 표면을 측정한 데이터로 통계적인 파라메타(parame- ter)를 추정하여, 인공부식시킨 부식재로 피로 강도를 평가하고, 또 부식된 구조물의 잔존수명을 예측할 수 있는 하나의 방법을 제시하고저 한다.

• 한국직업건강간호학회지
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• 제8권2호
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• pp.156-161
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• 1999

The EMG(Electromyography) analysis was used to identify the fact the degree of inclined step was selected as dependent variable and feet muscle fatigue was selected as a independent variable. In a final result from EMG test. the shift in median frequency (MF) with 20, 25, 30, 35 degree of inclined steps indicated that 30 degree step was identified as most effective for a decrease in feet muscle fatigue. In a department store, 80% of the workers are female standing sales workers. They work at standing on average 10 hours per day. They performed heavy duty jobs such as lifting, lowering. packing and carrying heavy materials. Furthermore, even though they have work shoes, they usually use various kind of high heels. Eventually, this situation develops low-back-pain (LBP) problems for female workers. In conclusion, it is recommended that a particular branch in a department store claimed this step can effectively to circulate blood and significantly decrease feet muscle fatigue in lower extremity.