• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.1
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• pp.167-174
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• 2003

Fatigue damage of 2.2Ni-1Cr-0.5Mo steel used fir high strength pressure tubes and vessels was evaluated using uniaxial specimens subjected to strain-controlled fatigue loading. Based on the fatigue test results from different strain ratios of -2. -i 0, 0.5, 0.75, the fatigue damage of the steel was represented by using a cyclic strain energy density. Mean stress relaxation depended on the magnitude of the applied strain amplitude. The high pressure vessel steel exhibited the cyclic softening behavior. Total strain energy density consisting of the plastic strain energy density and the elastic tensile strain energy density described fairly well the fatigue life of the steel, taking the mean stress effects into account. Compared to other fatigue damage parameters, fatigue life prediction by the cyclic strain energy density showed a good correlation with the experimental fatigue lift within a factor of 3.

• Child Health Nursing Research
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• v.12 no.2
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• pp.180-188
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• 2006

Purpose: The purpose of this study was to explore family function, social support, perceived quality of life(QOL) in adolescent period and to find out the correlations between family function, social support, perceived QOL in adolescents. Method: The questionnaire to get some information for this study consisted of adolescents'general characteristics, 20 questions regarding family function, 11 questions regarding social support, 8 questions regarding perceived QOL in adolescents. The subjects of this study consisted of 128 adolescents who were living in S area. The data were analyzed by percentage, mean, t-test, ANOVA and Pearson's correlation using the WINSPSS program. Result: The mean score for family function was 3.07(max. : 5) and there was significant difference according to middle-high school student. The mean score for social support was 2.86(max : 5) and there was no significant difference. The mean score for perceived QOL was 4.02(max score: 7) and there was significant difference according to disease condition. There was a positive correlation between family function, social support, perceived QOL in adolescents. Conclusion: Consequently, the development of program, policy assistance and policy implementation to elevate juveniles' perceived quality of life is strongly required.

• Journal of fish pathology
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• v.36 no.2
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• pp.349-360
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• 2023

Common carp (Cyprinus carpio) (Weight 23.05 ± 6.98 g, Length 12.65 ± 1.38 cm) were exposed to waterborne nitrite at 0, 50, 100, 200, 400 and 800 mg NO₂ ^-/L for 96 hours. The lethal concentration 50 (LC₅₀) of C. carpio exposed to waterborne nitrite was 398.6 mg NO₂ ^-/L. Hemoglobin, hematocrit and RBC count were significantly decreased by waterborne nitrite exposure. The MCV (mean mean corpuscular volume) (µl), MCH (mean corpuscular hemoglobin) (pg) and MCHC (mean corpuscular hemoglobin concentration) (%) were significantly increased. The inorganic component, plasma calcium, was significantly increased, and the organic components such as plasma cholesterol and total protein were significantly increased showing a similar tendency with calcium. In enzymatic components, the AST and ALT were also significantly increased by nitrite exposure. The results of this study indicate that exposure to nitrite can affect the survival and hematological physiology of C. carpio.

• Korean Journal of Construction Engineering and Management
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• v.17 no.4
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• pp.57-65
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• 2016

This study found a proper parametric life distribution based on maintenance history data of each bridge member under the jurisdiction of the Korea Expressway Corporation for the past 10 years by introducing the concept of reliability and suggested a measure to calculate the mean life and reliability of each bridge member using the parameter obtained with the maximum-likelihood classification. As a result of analyzing the exponential distribution, weibull distribution and log normal distribution being utilized frequently in order to find the parametric life distribution type which well described the life data of each bridge member, it was found that the log normal distribution and weibull distribution described the characteristics of the relevant life data the best. As a result of calculating the mean life of each bridge member based on the estimated parameter, the average life of the steel bridge coating was 18.51 years which was the longest, followed by the bridge deck as 17.56 years. The mean life of the drainage facility and the bridge bearing were 12.27 years and 12.57 years respectively, showing the shortest life.

• International Journal of Reliability and Applications
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• v.1 no.2
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• pp.115-121
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• 2000

The trend change in aging properties, such as failure rate and mean residual life, of a life distribution is important to engineers and reliability analysts. In this paper we develop a test statistic for testing whether or not the failure rate changes its trend using censored data. The asymptotic normality of the test statistics is established. We discuss the efficiency values of loss due to censoring.

• Journal of the Korean Data and Information Science Society
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• v.6 no.2
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• pp.65-76
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• 1995

The importance of left truncated and right censoring cases has considered for better information in medical follow-up and engineering life testing studies. We propose some estimation procedure for the mean residual life function with consistency and asymptotic normality on the left truncated and right censoring model. And then, the comparision with Kaplan-Meier estimator ignoring the left truncated effect and the small sample properities are investigated by asymptotic biases and M.S.E.'s thresh Monte Carlo study.

• Journal of the Korean Statistical Society
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• v.19 no.1
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• pp.80-87
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• 1990

In reliability and life testing the mean residual life (MRL) of an item plays a significant role. While there has been a great deal of discussion on the theoretical aspects of the MRL, good estimators of MRL have been difficult to obtain. In this paper we propose a new estimator of the MRL of items at a given age, which is especially good for a small sample. The new estimator compares favorably with the empirical MRL estimator for small samples.

• Journal of the Korean Home Economics Association
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• v.39 no.4
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• pp.105-120
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• 2001

The purpose of this study was to analyze on effects of midlife ego-identity and crisis on quality of life in married women. The data were obtained through 394 midwife married women who live in Kwangju and Chonnam. The results were as follows. (1) The mean scores of ego-identity and quality of life were higher than the medium point. The mean scores of crisis was a little lower than the medium. (2) The ego-identity was significantly influenced by religion, health condition, social intimacy, marital relations, and parent-child relations. The crisis was influenced significantly by income, health condition, marital relations, and ego-identity. And the quality of life was influenced significantly by religion, health condition, marital relations, parent-child relations, and crisis. (3) On the result of path analysis, religion, health condition, marital relations, parent-child relations, and crisis directly influenced the Quality of life. Besides, income, social intimacy, and ego-identity indirectly affected the quality of life.

• Journal of the Korean Society of Industry Convergence
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• v.21 no.2
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• pp.79-86
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• 2018

The purpose of this study is to compare life stress between primigravida and multigravida in advanced maternal age. A cross-sectional study was performed for 133 pregnancy women (primigravida group 53, multigravida group 80). The all women were old age (${\geq}35years$) and pregnant. We used the questionnaire to self-report general characteristics, obstetric characteristics and life stress. The average of participants age was 36.15 years old, primigravida was 36.08 and multigravida was 36.19. The mean of total life stress score was 2.68 and the total life score for pregnant women of lower education level was higher. The marital relationship of primigravida was lower than multigravida(mean, .06 vs. .26; p=.021). As our study shows that stress of marital relationship is higher in the multigravida than primigravida, the life stress care for advanced maternal age is important.

• Korean Journal of Hospice Care
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• v.5 no.1
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• pp.1-13
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• 2005

Purpose:The purpose of this study was to find the ways to improve a quality of life of cancer patients through the family support by analyzing the correlation between quality of life and family support that cancer patients perceived. Methods: The questionnaires for this study were collected from 43 cancer patients who were admitted in general hospitals at Gyounggido from July 2004 to August 2004. The questionnaire was composed of total 60 items, which were general characteristics of 18 items, family support of 11 items and quality of life of 31 items. Kang's(1984) scale of family support and Tae's(2000) scale of quality of life were used. The data were analyzed with SPSS WIN 10.0 program using frequency, mean±SD, t-test, ANOVA and Pearson's correlation analysis. Results: Forty three cancer patients answered the questionnaire. Twenty three patients was a male and 20 a female. Mean scale of family support according to general characteristics was 3.87±0.71. Mean scale of quality of life according to general characteristics was 5.89±1.08 and relatively high. The better degree of education, the higher quality of life significantly and the less physical discomfort, the higher quality of life significantly. The quality of life when the patient burdens the spouse with treatment cost was significantly higher. A correlation between degree of family support and quality of life was r=0.488 and the higher family support that cancer patients perceived, the higher quality of life significantly(p<0.001). Conclusion: The higher family support that cancer patients perceived, the higer quality of life significantly. We suggest concrete and systemic program for family support.