• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.973-974
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• 2013

• 산업경영시스템학회지
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• 제23권58호
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• pp.71-79
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• 2000

In this study, through the roadside interview, drivers'feeling about fatigue has been evaluated synthetically and systematically when they drive a vehicle according to their sex, vehicle type, driving career, etc. Also, with the human sensibility evaluation technique, we grasped the human sensibility structure for the fatigue in a vehicle and as an objective evaluation index for comfort and fatigue in a vehicle, we developed a sensibility database. Through the survey and research, extracting and understanding the importance of factors which have influence on the fatigue in driving can be used as basic data that can suggest more comfort and pleasant driving environment to drivers. Also, human sensibility database regarding to the comfort and fatigue in a vehicle can be used as basic data in ergonomic vehicle design, evaluation for seat , comfort seat development, development of vibration reduction method and so on.

• International Journal of Internet, Broadcasting and Communication
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• 제15권1호
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• pp.254-261
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• 2023

The purpose of this study was to investigate the effects of 8-week resistance training on muscle fatigue in men in their 50s and 30s. A total of 16 subjects (8 in their 30s and 8 in their 50s) were recruited, and moderate-intensity resistance exercise was conducted three times a week for eight weeks. EMG was measured before and after 8 week resistance training. Before 8 weeks exercise, MDF of pectoralis major significantly decreased in all groups, and MDF of triceps brachii significantly decreased only in the 30s group. After 8 weeks of exercise, MDF of pectoralis major significantly decreased in all groups, and MDF of triceps brachii significantly decreased only in the 30s group. The fatigue index before and after the 8-week exercise was changed only in the pectoralis major, and significantly decreased in the 30s group. As a result, the muscle fatigue level among the resistance exercises of men in their 50s may be similar to that of men in their 30s, and muscle fatigue can be reduced by 8 weeks of exercise.

• 대한예방한의학회지
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• 제19권2호
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• pp.67-74
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• 2015

Objective : The aim of this study was to investigate fatigue-related factors including socio-demographic variables and life styles among workers in the automobile manufacturing industry. Method : The subjects were 22,937 individuals who had received health examination by Korean Medical doctors and responded to questionnaires for 8 months from March to November in 2011. The fatigue index was measured by heart rate variability (HRV) in an automobile manufacturing industry. A multivariate analysis with SPSS version 19.0 was used to examine the relationship between fatigue and other factors including ages, smoke consumption, drinking frequency, exercise frequency, occupational category, conjugal condition. Results : In comparison between normal and very bad level of fatigue, factors of ages, smoking, drinking, and exercise showed significant difference(p<0.05). In addition, when normal and bad fatigue were compared, ages, smoking, exercise also produced significant difference(p<0.05). Furthermore, in normal and good level of fatigue comparison, occupation and smoking yielded significant difference(p<0.05). Finally, in other comparisons between normal and very good fatigue, exercise, smoking and occupation revealed significant difference(p<0.05). Conclusion : The results of this study suggest that age increase affects fatigue negatively, whereas exercise and drinking of once or twice per a week can have positive correlations.

• 한국자동차공학회논문집
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• 제11권5호
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• pp.89-94
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• 2003

Rolling stock structures such as bogie frame and car body play an important role for the support of vehicle leading. In general, more than 25 years' durability is needed for them. A lot of study has been carried out for the prediction of the fatigue life of the bogie frame and car body in experimental and theoretical domains. One of the new methods is a probabilistic fatigue lift evaluation. The objective of this paper is to estimate the fatigue lift of the bogie frame of an electric car, which was developed by the Korea Railroad Research Institute (KRRI). We used two approaches. In the first approach probabilistic distribution of S-N curve and limit state function of the equivalent stress of the measured stress spectra are used. In the second approach, limit state function is also used. And load spectra measured by strain gauges are approximated by the two-parameter Weibull distribution. Other probabilistic variables are represented by log-normal and normal distributions. Finally, reliability index and structural integrity of the bogie frame are estimated.

• 성인간호학회지
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• 제23권4호
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• pp.386-396
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• 2011

Purpose: This study was conducted to examine the level of physical activities at time points of pre-illness and current treatment, and the differences in body mass index (BMI), anxiety, depression and fatigue according to their physical activity in cancer patients undergoing chemotherapy. Methods: The survey was used with 126 cancer patients undergoing daily chemotherapy at injection room, cancer clinic of C University Hospital in G city. Data were collected from June to September, 2009 using a structured questionnaire. The data were analyzed by descriptive statistics, chi-square, Fisher's exact test and t-test using SPSS/WIN15.0. Results: The significant increase in physical activity was reported from pre-illness to the time in treatment (${\chi}^2$=69.027, p<.001). The anxiety level of the group with increased physical activity was significantly lower than those who did not (t=-2.218, p =.028). There were no significant differences in BMI, depression, and fatigue according to physical activity. Conclusion: The level of physical activity was significantly associated with the anxiety level of the cancer patients undergoing chemotherapy. Cancer patients should been encouraged regular physical activity during chemotherapy treatment. And an appropriative nursing intervention should be established in order to motivate cancer patients to increase physical activity.

• 한국기계가공학회지
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• 제8권4호
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• pp.69-75
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• 2009

Recently developed automotive components are getting lighter providing a higher fuel efficiency and performance. Following the current trend, this study proposes a structural optimization method for the lower control arm installed at the front side of a Vehicle. Lightweight design of lower control arm can be achieved through design and material technology. In this research, the shape of lower control arm was determined by applying the optimization technology and aluminum was selected as a steel-substitute material. Strength performance is the most important design requirement in the structural design of a control arm. This study considers the static strength in the optimization process. For the optimum design, the durability analysis is performed to predict its fatigue life. In this study, the kriging interpolation method is adopted to obtain the minimum weight satisfying the strength constraint. Optimum designs are obtained by the in-house program, EXCEL-Kriging. Also, based on the optimum model obtained for the static strength, the optimization of Index of Fatigue Durability is carried out to get th optimum fatigue performance.

• 대한의용생체공학회:의공학회지
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• 제34권1호
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• pp.1-7
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• 2013

According to the frequent use of mobile devices, risk of repetitive strain injury for the finger joints was increasing recently. The purpose of this study was to investigate the difference of muscular endurance limit of the thumb between adults and children. A total of thirty subjects (15 adults: $41.0{\pm}7.9$ years and 15 children: $9.5{\pm}2.7$ years) was recruited for this experiment. Maximum voluntary contraction (MVC) of the thumb was measured for 100 trials for each subject by using a push-pull gauge. From the maximum peak value obtained, three main factors (MVC, endurance limit, and fatigue index) were defined to quantify fatigue characteristics of the thumb flexor muscle. The experimental results showed that the mean of MVC, endurance limit, and fatigue index of the children were approximately 50% compared to the adults (p < 0.001). From the results of Pearson correlation test, the endurance limit was highly correlated with weight, age, hand length rather than height. Based on this study, children are more vulnerable to repetitive task using the thumb such as text/SNS messaging, gaming, and scrolling.

• 해양환경안전학회지
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• 제14권1호
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• pp.77-82
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• 2008

최근 선박충돌사고 또는 좌초사고와 같은 중대한 해양사고를 조사할 때, 사고 관련자의 피로도(Fatigue)가 선박의 안전운항에 부정적인 영향을 미치는 인간과실(Human error) 유발요인으로 작용하여 항해사의 인지능력 및 업무수행능력을 저하시키는 중요한 요인으로 인식되고 있고, 이에 대한 많은 연구가 수행되고 있다. 본 연구에서는 국내 해양사고관련자에 대한 피로도를 체계적으로 조사 분석하기 위한 일환으로 미국연안경비대의 피로도 조사프로그램을 분석하여 국내 해양안전심판원 웹사이트에 조사프로그램을 구현하였으며, 그 결과를 고찰하여 효율적인 피로도조사가 수행 가능하도록 몇 가지 방안을 검토하였다.

• 한국소음진동공학회논문집
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• 제22권2호
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• pp.123-129
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• 2012

It was previously suggested the design sensitivity analysis based on transmissibility function to identify the most sensitive response location over a small design modification. On the other hand, energy isoclines were used to predict the fatigue damage with acceleration response only. Both of previous studies commonly tackle the engineering problem using the acceleration response alone such that it may be possible to investigate the relationship between sensitivity analysis and accumulated fatigue damage. In this paper, it is suggested the novel method of vibration fatigue prediction using design sensitivity analysis to enhance the accuracy of predicted accumulated fatigue. Uni-axial vibration testing is performed with a simple notched specimen and the prediction of fatigue damage is conducted using accelerations measured at different locations. It can be concluded that the accuracy of predicted fatigue damage is proportional to the sensitivity index of the responsible location.