• International Journal of Concrete Structures and Materials
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• v.11 no.2
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• pp.247-259
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• 2017

This paper presents a fatigue assessment model that was developed for corroded reinforced concrete (RC) beams strengthened using prestressed carbon fiber-reinforced polymer (CFRP) sheets. The proposed model considers the fatigue properties of the constituent materials as well as the section equilibrium. The model provides a rational approach that can be used to explicitly assess the failure mode, fatigue life, fatigue strength, stiffness, and post-fatigue ultimate capacity of corroded beams strengthened with prestressed CFRP. A parametric analysis demonstrated that the controlling factor for the fatigue behavior of the beams is the fatigue behavior of the corroded steel bars. Strengthening with one layer of non-prestressed CFRP sheets restored the fatigue behavior of beams with rebar at a low corrosion degree to the level of the uncorroded beams, while strengthening with 20- and 30%-prestressed CFRP sheets restored the fatigue behavior of the beams with medium and high corrosion degrees, respectively, to the values of the uncorroded beams. Under cyclic fatigue loading, the factors for the strengthening design of corroded RC beams fall in the order of stiffness, fatigue life, fatigue strength, and ultimate capacity.

• Journal of the Korean Society of Safety
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• v.33 no.5
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• pp.164-169
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• 2018

A detailed fatigue evaluation procedure was developed to mitigate the excessive conservativeness of the conventional environmental fatigue evaluation method for the pressurizer spray line elbow of domestic new nuclear power plants. The pressurizer spray line is made of austenitic stainless steel, which is relatively sensitive to the environmentally assisted fatigue, and has a low degree of design margin in terms of environmentally assisted fatigue due to the thermal stratification phenomenon on the pipe cross section as a whole or locally. In this study, to meet the environmental fatigue design requirements of the pressurizer spray line elbow, the new environmental fatigue evaluation has been performed, which used the ASME Code NB-3200-based detailed fatigue analysis and the environmental fatigue correction factor instead of the existing NB-3600 evaluation method. As a result, the design requirements for environmentally assisted fatigue were met in all parts of the pressurizer spray line elbow including the fatigue weakened zones by thermal stratification.

• The Journal of Internal Korean Medicine
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• v.27 no.2
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• pp.510-520
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• 2006

Objectives: The aim of this study was to investigate the correlation between fatigue degree and Comprehensive diagnosis of Qui Xui Shui in patients with functional dyspepsia. There again, we investigated an association between scores obtained from Comprehensive diagnosis of Qui Xui Shui and state of skin sympathetic tone or cardiovascular reactivity. Methods: Subjects were 56 patients with Functional dyspepsia and 8 healthy People. Fatigue degree was assessed by questionnaires consisting of subjective complaints of fatigue. Comprehensive diagnoais of Qui Xue Shui was investigated by questionnaire and physical examination, total score and composition score were calculated from the symptom score. Skin sympathetic tone was measured by Ryodoraku Score(RS) and Cardiovascular Reactivity(CV Reactivity) was checked by Pulse diagnostic apparatus. All patients were divided into two groups by RS $40{\mu}A$(below and above) or by CV Reactivity(decreased and increased or not decreased). Results: There was highly significant correlation between Fatigue Degree and total score and each composition score of Comprehensive diagnosis of Qui Xui Shui. And total score of patients was significantly higher than that of health controls : in the patients, females than males. Significance related with the level of RS $40{\mu}Aor$ the state of CV Reactivity were not remarkable in both patients and health control group. Conclusions: Fatigue degree seems to have a special feature reflecting the state of Comprehensive Diagnosis of Qui Xui Shui in patients with functional dyspepsia.

• Journal of Korean Academy of Nursing
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• v.28 no.4
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• pp.908-919
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• 1998

The purpose of this study was to get some basic data for health care for working women, especially or hospital nurses. The number of subjects was 796 nurses from one general hospital and four private educational hospitals. The data were collected from February to April, 1988 using the questionnaire "Symptom Table on Fatigue Perception" designed by the Research Committee of Industrial Fatigue in Hygienic Association of Japan Industry. The collected data were analyzed using means and standard deviations for the subjective symptoms of fatigue and each item as an independent variable was analyzed by T-test and ANOVA test. The results are as follows 1) The mean score for degree of fatigue was 1.89 and the degree of fatigue for physical symptoms had highest score of 2.04, the next was psychological symptoms at 1.89, and neuro -sensory symptoms were the lowest at 1.74. Among the fatigue symptoms, the item scored most frequently was "Legs feel heavy" with a mean score of 2.40 and the least frequent item was "My hand and foot trembled" with a mean score of 1.40. 2) With the respect to the general characteristics of subjects, there were statistically significant difference according to age (F=17.039, p=.000), state of marriage(t=5.381, p=.000) presence of children(t=5.134, p=.000), clinical experience (F=16.663, p= .000), present position(F=18.204, p=.000), working place(F=12.598, p=.000), duty time(F=9.068, p=.000), monthly wages(F=7.361, p=.000). satisfaction about the pay and treatment at work(t=-5.511, p=.000), relation the doctors(t=-4.593, p=.000) the doctors(t=-4.593, p=.000)

• Journal of the Korea Safety Management & Science
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• v.11 no.4
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• pp.57-67
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• 2009

The psychosocial stress and musculoskeletal disorders(MSDs) have been one of major health problems for hospital workers. This study tried to understand the relationship between symptoms associated with MSDs and risk factors such as working posture, job stress, psychosocial stress and fatigue. A total number of 655 hospital workers participated in this study. Specifically, REBA was applied for evaluating working posture and a checklist prepared by KOSHA(Korean Occupational Safety and Health Agency) was used for symptom survey. A questionnaire from KOSHA was also used for collecting data associated with job stress, psychosocial stress and fatigue. All these data were formulated and modeled by path analysis which was one of major statistical tools in this study. Specifically, path analysis for the data we collected came up with several major findings. As a result, as for body part(neck), (waist) and (arms) the degree of risk of work posture measured with the use of job stress(KOSS), psycho-social stress(PWI-SF) and REBA is significantly more affected by fatigue than muscular skeletal disease related consciousness symptom. However, regarding bod(wrist), the degree of risk of work posture measured with the use of job stress(KOSS) and REBA is directly affected by muscular skeletal disease related consciousness symptom. This study is meaningful in that the study clarified the causal relations of the degree of risk of work posture, degree of fatigue, and muscular skeletal disease related consciousness symptoms by each body part measured with the use of work stress(KOSS), psycho-social stress(PWI-SF) and REBA.

• Journal of Korean Academy of Nursing
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• v.29 no.2
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• pp.248-257
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• 1999

The purpose of this study was to identify basic data for the health fare of normal pregnant women. The number of subjects was 779 pregnant women who received prenatal care in two University hospitals. The data, which were collected from June to October, 1998. and used the questionnaire “Symptom Table on Fatigue Perception” designed by the Research Committee of the Industial Fatigue in Hygienic. Association of Japan Industry. The collected data were scored by use of means and standard deviations according to the subjective symptoms of fatigue and each item as an independent variable was analysed by t-test and ANOVA test. The results are as follows : 1) Degree of subjective fatigue showed as an average of 1.81. Fatigue as physical symptoms had the highest score with 2.09. followed by neuro-sensory symptoms, 1.69 and psychological symptoms had the lowest score 1.66. 2) With the respect to the general characteristics of the subjects. there were statiscally significant difference in experience of pregnancy(t＝-2.286, p＝.023). wanted pregnancy(t＝-2.935, p＝.004), parity(t＝-2.429, p＝.015), sleeping time(F＝3.478, p＝.031). and presence of other child(t＝2.347, p＝0.19).

• Journal of Korean Institute of Industrial Engineers
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• v.19 no.4
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• pp.87-96
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• 1993

Spectrum analysis of surface electromyogram (FMG) signals is an effective approach to the study of localized muscular fatigue during isometric contraction. Many investigators have con firmed the frequency of the EMG signals being lowered during sustained contaction. In this study, the cyclic loading tasks were performed, and a comparison was made for the median power frequency shift pattern of the EMG signals with the sustained contraction of the same load. The median power frequency shift of the EMG signals for the cyclic loading task was found to be a part of that for the sustained contraction. Based on this result, a new muscle fatigue index was computed by normalizing the duration of the sustained contraction. A fatigue index was obtained as a function of exertion level and the work/rest schedule. With the proposed fatigue index, it is possible to evaluate or predict the degree of muscular fatigue for a physically demanding task.

• Journal of muscle and joint health
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• v.5 no.2
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• pp.206-221
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• 1998

The purpose of this study was to validate translated Multidimensional Assessment of Fatigue(MAF) scale. The scale is a 16-item scale that measures four dimensions of fatigue : severity, distress, impact, timing. Fourteen items are numerical rating scales and 2 items have multiple choice responses. Data were collected from the 137 patients with rheumatoid arthritis after content validation. Criterion validity was tested by correlation coefficient with Piper Fatigue Scale, which resulted in 0.7573(p<.0000). Construct validity was tested by item analysis and factor analysis. Corrected item-total correlation coefficients were 0.63-0.88. And factor analysis showed 2 factors : fatigue degree factor and fatigue impact factor. These two factors explained 73.5% of total variance. Reliability of internal consistency was 0.96 in Cronbach's alpha. Further validation study is necessary in each factor in other settings with other subjects.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.302-307
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• 2004

This paper reviewed characteristics of fatigue crack behavior observed by changing various shapes of initial crack and magnitudes of loading in compact tension shear(CTS) specimen subjected to shear loading. In the high-loading condition, fatigue crack under shear loading propagated branching from the pre-crack tip. Meanwhile, the secondary fatigue crack in the low-loading condition which was created in the notch root due to friction on the pre-crack face grew to a main crack. Influenced by the mode II loading condition, fatigue crack propagation retardation appeared in the initial propagation region due to the reduction of crack driving force and friction on crack face. In both cases, however, fatigue cracks grew in tensile mode type. Propagation path of fatigue crack under the shear loading was 70 degree angle from the initial crack regardless of its shape and load magnitude.

• Korean Journal of Occupational Health Nursing
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• v.7 no.2
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• pp.177-185
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• 1998

The purposes of this study were to investigate the effects of farming in greenhouses with respect to subjective fatigue symptoms among farmers and the degree of symptoms. The study compared 176 green-house farmers with 216 open field farmers using a subjective fatigue symptoms rating scale developed by the Industrial Research Institute of Fatigue, Japanese Association for industrial Hygiene. 1. With respect to complaint rates of the subjective fatigue symptoms, the results indicated that greenhouse farmers have, in order of severity, high degrees of low back pain, difficulty in collecting thoughts, and apt to forget. 2. With respect to cumulative scores of fatigue symptoms, the results indicated that both groups of farmers exhibited a lack of attentiveness and a high degree of dullness and sleepiness(category I), body projection of fatigue(category II), and difficulty in concentration(category III). 3. With respect to general characteristics, it was found that the degrees of subjective fatigue symptoms were found to be higher among females, people with lower educational levels, and the elderly, regardless of the group. 4. With respect to work related factors, farmers with more years of experiences were found to have higher degrees of subjective fatigue symptoms, except for open field farmers with less than nine years experience. Both groups of farmers were found to have high degrees of subjective fatigue symptoms when working less than eight hours a day and less than six months a year. 5. With respect to health habits, for people who get less than eight hours of sleep per day exhibited higher fatigue scores than people who get more than eight hours. People who do not smoke and drink also exhibited higher fatigue scores than people who smoke and drink. 6. The results of multiple regression showed that the risk factors related to the subjective fatigue symptoms of farmers in the greenhouse group were ages, levels of education, sex and for the comparison group, were sex. years of farming, and hours of sleep. The R-square were 12.5% in the greenhouse group and 12.1% in the comparison son group. The differences between the greenhouse and open field farmers in the degrees of fatigue symptoms were found not to be statistically significant even if the working conditions of the greenhouse farmers were poor. This may be attributed to non-work related factors, i.e., social, economical, and psychological factors among greenhouse farmers.