• Journal of Hospice and Palliative Care
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• v.7 no.2
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• pp.179-188
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• 2004

Purpose: The purpose of this study was to investigate the degree of fatigue and its related factors in cancer patients during chemotherapy. Methods: The subjects of this study consisted of 90 patients over 20 years old who were receiving chemotherapy at the injection room of the o.p.d. and ward admission care unit in a University hospital located in Gwang-ju city and data were collected from August 8th to October 2nd, 2002. Collected data were analysed using SPSS v 10.0. to obtain summary statistics for the descriptive analysis, t-test, ANOVA, pearson correlation, and multiple regression. Results: 1. Fatigue of the subjects was significantly correlated with physical distress score. and 6 items of subscale those were nausea, vomiting, anorexia, pain, and immobility, showed statistically significant correlation. 2. Fatigue of the subjects showed statistically significant differences according to a nap satisfaction. Fatigue of the subjects was significantly correlated with mood state, Also, all 5 items of subscale, which are those were anxiety, confusion, depression, energy, and anger showed statistically significant correlations. 3. Fatigue of the subjects showed statistically significant differences according to metastasis, chemotherapy cycle, post operation existence, post radiation therapy existence. There were significant negative correlation between fatigue and hematocrit and fatigue and weight change. There was no significant correlation between fatigue and spiritual well-being state. With the result to multiple regression, Immobility, Anorexia, Anger explained fatigue by, pain, and immobility showed statistically significant correlation.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.17 no.3
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• pp.333-340
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• 2004

The use of the othotropic steel deck is steadily increased due to the advance of the technology in the steel bridges which recently have been longer. But the othotropic steel deck bridge is the structure that is very fragile to the fatigue, especially, the fatigue crack at the cross of the longitudinal rib and transversal rib is one of the biggest problems that othotropic steel deck bridges have. The causes of these fatigue cracks come from the secondary stress on out-plane behavior of transversal rib. In this study, we conducted the experiment to find the optimal details to improve fatigue strength on intersection between longitudinal rib and transversal rib in the othotropic steel deck bridge through numerical analysis using the experiment of the fatigue in the 3-dimensional real structure and program LUSAS. As a result of study, it is showed that the details of the korean standard section attached with a curved bulkhead plate is the most profitable. And, it is indicated that the stress which is generated when the reform improved section by parametic study can be reduced by about 50% at most or more. Along with the reduced stress and the longer interval between transversal ribs(G=400), the decreased steel amount by 4% and the shortened welding length by 34% make it possible to produce the othotropic steel deck bridge which is strong against fatigue.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6D
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• pp.881-893
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• 2008

The major objective of this study is to investigate the fatigue damage factor evaluation of immovability crossing for railway turnout by the field test and qualitative analysis. From the field test results of the servicing turnout crossing and qualitative analysis with frictional wear which section stiffness decreased, it was evaluated fatigue life of servicing turnout crossing. Most design practices have not taken advantage of the advanced theories in the modern fracture mechanics and finite element analysis due to complexity of analysis as well as the large quantity of vaguely defined parameters in actual designs. This paper considers fatigue problems in turnout crossing using effective analytical and design tools from the field of qualitative constraint reasoning. A set of software modules was developed for fatigue analysis and evaluation, which is easily applicable in engineering practices of designers. The techniques enable the use complex analysis formulations to tackle practical problems with uncertainties, and present the design outcome in two-dimensional design space solution. Appropriate engineering assumptions and judgments in carrying out these procedures, often the most difficult part for practicing engineers, can be partially produced by using qualitative reasoning to define the trends and ranges, interval constraint analysis to derive the controlling parameters, as well as design space to account for practical experience.

• Korean Journal of Crystallography
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• v.10 no.1
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• pp.13-19
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• 1999

저합금강인 SCM415강에 대한 플라즈마 질화의 변수에 따른 질화특성을 관찰하여 최적공정을 확립한 후 기존의 질화법인 염욕질화와 가스질화 되어진 시편과 피로특성을 비교하였다. 가스조정비는 질소대 수소의 비가 3:1일 때 가장 높은 표면강도를 가지며, 온도는 높아질수록 표면강도는 낮아지고 유효경화깊이는 깊어지는 것을 알 수 있었다. 또한 질화시간이 증가될수록 표면경도는 낮아지고 유효경화깊이는 깊어졌다. 본 플라즈마 질화장비에서의 최적공정조건은 공정온도 500℃, 공정시간 4시간, 질소와 수소의 비가 3:1으로 관찰되었고, 이 때 표면경도는 1181 Hv, 화합물층의 깊이 17 ㎛, 유효경화깊이 450 ㎛로 측정되었다. 가스질화 되어진 시편의 표면경도는 945 Hv, 유효경화깊이 250 ㎛였고, 염욕질화 되어진 시편의 경우는 각 846 Hv, 300㎛으로 관찰되었다. 또한 플라즈마 질화공정을 거친 질화강과 가스질화, 염욕질화 되어진 질화강의 피로특성을 평가한 결과 플라즈마 질화강이 가스질화, 염욕질화 되어진 질화강에 비하여 1.5∼2배의 우수한 피로특성을 나타내었다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.583-586
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• 2011

가새골조의 정확한 내진성능평가를 위해서는 실험과 유사한 이력거동과 파단 시점을 잘 예측할 수 있는 해석적 모델이 필요하다. 가새의 이력거동을 모사히기 위해 본 연구에서는 이전 연구자들에 의해 제안된 물리적 이론 모델을 사용하였다. 또한, 가새부재의 국부좌굴에 의한 파단 예측을 위해 피로변수의 보정계수를 도입한 손상 지표를 개선하였다. 결과적으로 실험과 해석 결과를 비교하여 콘크리트충전 각형 강관가새부재의 국부좌굴 효과를 반영한 피로 보정계수를 판폭두께비에 따라 회귀분석을 통해 결정하고, 본 연구에서 제안한 해석 모델의 결과와 이전 연구의 결과를 비교하여 검증하였다.

• Journal of dental hygiene science
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• v.14 no.3
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• pp.325-331
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• 2014

The purpose of this study was to examine the self-perceived fatigue among 262 dental hygiene students, who have recently experienced clinical practice. In this study, a structured self-reported questionnaire was used to assess and analyze the severity of fatigue among the population. This study was performed from January to September in 2013 to effectively encompass clinical practice. The results are as follows: The self-perceived fatigue of the subjects was significantly higher in a subjective unhealthy group than a subjective healthy group (p=0.000), in a group that was unsatisfied with their program than a group that was satisfied with it (p=0.000), in a group that had dissatisfaction in clinical practice than a group that had satisfaction with it (p=0.000), in a group that had over five weekly of clinical practice than a group that didn't (p=0.000), in a group that had more than 100 patients a day than a group that didn't (p=0.000), in a group that had conflicts between fellow staff than those who didn't (p=0.000), in a group that did not exercise regularly than a group that did (p=0.016). The result of using multiple regression analysis revealed that the variable factors affecting the degree of the self-perceived fatigue were; subjective health status, satisfaction with a clinical practice, the length of clinical practice, the number of patients, and staff conflicts. These variable factors have the explanatory power of 44.5%. In conclusion, to decrease fatigue and allow students in clinical practice to perform effectively, clinical practice educators need to actively participate as a community and develop programs that will decrease the fatigue of students. In addition, in-depth research is needed on the effects of outside factors and variables affecting fatigue.

• Journal of the Korea Concrete Institute
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• v.16 no.5 s.83
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• pp.581-589
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• 2004

This paper compares the fatigue behaviors of concretes subjected to flexural and split-tensional loadings, and proposes the fatigue reliability models based on experimental results and reliability analysis. The fatigue tests were performed for the specimens of $150 mm{\times}75 mm$ split tensional cylinders and $150 mm{\times}150 mm{\times}550 mm$ flexural beams under constant loadings at three levels (70, 80 and $90\%$) with 0.1 stress ratio, 20 Hz loading speed and sine wave. The reliability analysis on fatigue data was based on Weibull distribution of two-parameters. From fatigue test results, two criteria were proposed to reject the experimental fatigue data because of statistical variation of concrete fatigue data. Two parameters ($\alpha$and u) of Weibull distribution were obtained using graphical method, moment method and maximum likelihood method. The probability density function(P.D.F) and cumulative distribution function(C.D.F) of the Weibull distribution for fatigue life of pavement concrete were derived for various stress levels using parameters, $\alpha$ and u. The goodness-of-fit test by Kolmogorov-Smirnov test was acceptable at $5\%$ level of significance. Based on reliability analysis, a fatigue model for pavement concrete was proposed and compared from existing models.

• Journal of Korean Society of Steel Construction
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• v.18 no.4
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• pp.417-426
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• 2006

Various fatigue damages have been reported in orthotropic steel deck structures put upon girders. These damages are caused by complex behaviors of the deck, which is directly subjected to vehicle loads. To estimate the causes of fatigue cracks at the welded connected parts of the trough rib and the flor beam, and the trough rib and the deck plate, in orthotropic steel deck structures, FE analyses were first, performed in this study. Parameter studies were carried out to suggest effective structural details that consider fatigue, in which the main parameters are the thickness of the deck plate, the shape of the connection of the trough rib and the flor beam such as the slit form, and the welding length. This study suggests that the effective structural details improved the fatigue strength and discusses.

• The Journal of the Korea Contents Association
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• v.16 no.2
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• pp.456-466
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• 2016

The purpose of this study was to identify factors affecting clinical practice-related fatigue among undergraduate nursing students. The data were collected from a questionnaire distributed among 129 juniors and seniors (3rd and 4th year students) in nursing college at the G city, who were at the end of clinical practice. Multiple regression analysis found that the significant major predictors of clinical practice-related fatigue among nursing students were sleep quality (${\beta}=.30$), anxiety (${\beta}=.26$), exercise frequency (${\beta}=-.21$) and clinical practice stress (${\beta}=.19$). These variable factors could explain 33.6% of clinical practice-related fatigue among nursing students. This study suggests that sleep quality, anxiety, exercise frequency, and clinical practice stress are significant factors of clinical practice-related fatigue among nursing students. Therefore, strategies improving sleep quality and exercise and managing anxiety and stress should be developed to reduce the fatigue for nursing students during clinical exposure.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.9
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• pp.5700-5707
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• 2014

This descriptive study was performed to identify the factors that influence fatigue in patients with type 2 diabetes mellitus. A total of 117 subjects were recruited from a university hospital in J city. For data collection, a questionnaire survey was performed between May 1 and June 28 2013. Data were analyzed by descriptive statistics, t-test, one way ANOVA, Pearson Correlation, and multiple regression analysis using the SPSS WIN 15.0 package. The mean fatigue scores of the subjects was 2.80. Depression, age, and time since the diagnosis were the variables influencing fatigue. The total explanatory power of these factors on fatigue was 40%. In conclusion, it is essential to develop a fatigue control nursing program considering depression, age and time since the diagnosis for patients with type 2 Diabetes mellitus.