• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.5
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• pp.1191-1198
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• 2015

In this study, vehicle/track interaction analysis by the Saemaul powered vehicle was carried out. The prediction equation for the bending stress of rail was estimated using the rail bending stress by the rail surface irregularities at welds. Also, the fatigue analysis using a S-N curve of welds in the conventional railway was carried out. We estimated the fatigue life of CWR by the fracture probability. By the rail grinding, the fatigue life of CWR was evaluated in consideration to reduce the rail bending stress through removing the rail surface irregularities. Therefore, it presented the fatigue life of CWR according to the rail grinding execution plan in the conventional railway.

• Proceedings of the Korea Contents Association Conference
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• 2014.11a
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• pp.235-236
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• 2014

군의 교육훈련간 디브리핑과 피드백 장치 활용을 통한 심폐소생술 교육방법을 적용하여 보다 효과적인 교육 방법을 확인하고 심폐소생술 수행 전 후 피로도를 검사하여 심폐소생술 술기가 숙달된 인원과 숙달되지 않은 인원의 피로도 차이를 분석함으로써 심폐소생술 교육프로그램의 기초자료를 제공하고자 한다. 현재 야전에서 응급처치교육을 받은 적이 없는 비 의무병인자로 전투병 생존법 교육 소집 대상자 중 참여 희망자 50명을 대상으로 하였다. 연구방법은 3가지 교육방법(디브리핑, 피드백장치, 디브리핑과 피드백장치 조합) 을 적용한 3개의 그룹에서 1,2,3차의 평가와 전체 디브리핑을 통해 심폐소생술 수행능력의 질적 향상에 미치는 영향과 동일 대상 중 희망자 20명에 한하여 심폐소생술 수행(5분) 전 후 혈중 젖산 농도 측정 및 주관적인 문답(1~10점)을 통해 심폐소생술 수행에 따른 피로도 실험을 진행하였다. 3가지 교육방법에 따른 심폐소생술수행능력 향상은 모든 그룹에서 유의하였으며(p<.001), 그룹별 심폐소생술 수행능력 향상효과의 차이는 디브리핑과 피드백장치를 조합하여 적용한 그룹에서 유의하게 높았다(p<.01). 심폐소생술 수행능력이 숙달되기 전 후의 피로도에 대해서는 본인이 느끼는 피로도는 유의한 차이는 없었으나 혈중 젖산농도에 따른 피로도는 유의한 차이로 전보다 후가 낮아졌다(p<.01).

• Korean Journal of Materials Research
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• v.4 no.2
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• pp.219-226
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• 1994

In the comparison result of residual strain calculated from the load-strain curve under the repeated loading cycles, it was found that the larger the laminates is, the larger the stiffness of GFRP pipes under fatigue load is. This phenomenon is true until the fatigue failure. According to the S-N curves drawn by the regression analysis on the fatigue test results, the fatigue strength for percentage of the static ultimate strength increases by increasing the laminates of GFRP pipes. The fatigue strength for 2, 000, 000 repeated loading cycles In GFRP pipes with the laminates varing 15, 25, 35 shows 75.2%, 79.5%, 84.2% on the static ultimate strength, respectively.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.669-672
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• 2011

본 논문은 사하중 절감이 중요한 장지간 교량에 있어서 유리한 구조를 가지는 강바닥판의 성능 강화를 위한 수치해석 연구를 실시하였다. 이미 국내외에서는 다수의 강바닥판을 이용한 교량의 시공 사례가 많으며, 앞으로도 시공 또는 계획될 해상 장지간 교량에서도 강바닥판 교량의 사례가 많을 것으로 판단된다. 강바닥판 교량은 공기를 단축할 수 있으며, 들보의 높이가 작아서 날씬한 형상으로 할 수 있기 때문에 미관을 향상 시킬 수 있을 뿐만 아니라 가설 공사비를 절감시킬 수 있는 등 많은 장점을 갖고 있다. 하지만 강바닥판은 이상과 같이 장점을 갖는 구조이지만 비교적 얇은 강판을 복잡한 형상으로 용접하여 조립함에 용접 결함, 잔류응력, 면내 및 면외 변형의 발생 등의 문제점이 지적되고 있다. 따라서 외국에서는 강바닥판의 피로 손상에 대한 실험 및 연구로 많은 자료를 확보하고 있으며, 국내에서도 국내 현실에 맞는 강바닥판의 피로거동 및 피로강도 향상방안에 관한 연구가 더욱더 필요하다. 본 연구에서는 국내교량에 적용되고 있는 구조상세 및 구조해석을 실시하여 강바닥판의 피로거동과 응력 특성을 파악하고, 피로강도를 향상하는 방법으로 Bulkhead Plate와 수직리브 형상 및 부착에 따른 거동을 분석하고, 최적상세를 도출하여 강바닥판의 적극적인 활용화에 그 목적이 있다.

• Journal of Digital Convergence
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• v.16 no.9
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• pp.301-307
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• 2018

We study convergent influence on depression and its association with self-esteem, fatigue and psychosocial stress among General Hospital Administrative Staff(GHAS). The subjects were 201 randomly extracted GHAS from 9 general hospitals in J City, Data collection was carried out via a structured self-administered questionaries from Jul. 3rd, 2017 to Jul. 29th, 2017. Depression was positively correlated with three sub-domains of fatigue and psychosocial stress, and it was negatively correlated with self-esteem. With the analysis of covariance structure, depression was more influential on self-esteem than fatigue and psychosocial stress. The study found the higher fatigue and psychosocial stress, and the lower self-esteem tend to increase depression. The results indicate that the efforts, to increase self-esteem, and to decrease fatigue and psychosocial stress, are required to decrease the depression of GHAS. The results are expected to be useful for industrial health education and job management to decrease the depression of GHAS. In the following study, the analysis about convergent additional factors of influence on the depression of GHAS will be needed.

• The Journal of Society for e-Business Studies
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• v.21 no.1
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• pp.33-63
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• 2016

The diffusion of smartphone has make people engaged in communication with mobile messenger in everyday life. To understand the rapid growth of mobile messenger usage, this study investigates the unique features of mobile messenger services as communication media. Based on the media synchronicity theory and literature about online communication, we identify the functional and emotional features of mobile messenger. In particular, this study demonstrates that functional and emotional features of mobile messenger would influence intimacy and fatigue. Also, intimacy and fatigue, as mediating variables, have an impact on user satisfaction and commitment toward mobile messenger service. The results of this study provide practical implications for mobile messenger providers and users which attempt to facilitate positive effect such as intimacy among users and reduce negative effect such as fatigue on mobile messenger communication.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.2256-2264
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• 2014

This study was a descriptive study to identify the effect of health promoting behavior on fatigue and depression and to investigate these levels among nurses. Data were collected from September 19th 2012 to September 25th 2012 by questionnaires from 243 hospital nurses of 3 hospitals in Kyungsang-Bukdo. The data was analyzed using descriptive statistics, t-test, Pearson's correlation coefficients, ANCOVA, and Stepwise multiple regression. The result showed that in health promoting behavior, shift nurses had higher scores than it of non-shift nurses. The health promotion behavior predictors of fatigue were spiritual growth and stress management and the predictors of depression were physical activity and interpersonal relationship. This results suggest that development of professional health promoting program which is strengthened these parts of spiritual growth, stress management, physical activity and interpersonal relationship, is needed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.2
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• pp.554-561
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• 2012

The purpose of this study was to identify the relationship between anxiety, anger and fatigue among stress factor in clinical practice of nursing students. The subjects were 197 nursing students who have practiced at the hospital in T city. Data was analyzed by using descriptive statistics, ANOVA, t-test and pearson's correlation coefficient. The mean score for stress was 3.82. The mean score for anxiety was 48.82. The mean score for anger was 1.17. The mean score for fatigue was 30.96. The factor of stress was a significant difference of anxiety according to conference, theory and practice, satisfaction of clinical practice. The factor of stress was a significant difference of anger according to report, theory and practice, orientation, nurse, environment. The factor of stress was a significant difference of fatigue according to conference, orientation, environment, patient relationship. In results, This study revealed that there was a significant correlation among stress, anxiety, anger and fatigue of nursing students in clinical practice.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.6
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• pp.1576-1582
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• 1990

To examine small fatigue crack behavior, the crack opening displacement (COD) was measured for surface cracks in the range of few tens to hundreds .mu.m using the computerized Interferometric Strain/Displacement Gage (ISDG) which could measure the relative displacement with a resolution of 0.02 .mu.m. The load-COD record is stored and analyzed after the test to determined the opening load. Single-edge notched specimens, 2.3mm thick, of Al 2024-T3 were precracked at load ratios of 0.0, -1.0 and -2.0 to make small fatigue cracks. The opening loads were measured these small cracks and compared with those of long cracks. The opening load ratios for the short cracks are about 10% smaller than those for long cracks at positive R-ratios, but are about 100% smaller at negative R-ratios.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.4
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• pp.439-446
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• 2010

Fracture mechanics is used for the detailed analysis of the failure of high-speed rotating cylindrical vessels. The general procedure for the analysis of fatigue life and failure used in this study is summarized; the initial material properties are also described. The results of the theoretical stress analysis are compared to the observed magnitude of the stress under the operational condition. The fracture-surface configurations observed under both optical and scanning electron microscopes are used to investigate the progress of fatigue crack propagation. Fatigue life estimates obtained by using the Paris model are compared to the actual service life of the high-speed rotating pressure vessel.