• Journal of Families and Better Life
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• v.1 no.2
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• pp.1-20
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• 1983

The purpose of this study is to analyze the planning dimensions according to homemaker's age and education. In this study the dimensions of planning are participation, time span , significance, specifity and flexibly. The subject areas of planning are family economy, household activities, child rearing and purchasing. Questionnaires were given to the selected 181 homemakers living in Seoul and Incheon. Data were analyzed by frequency, percent, x2 -test, F-test. The result are as follows: 1) There are significant differences in planning dimensions according to homemaker's age and education in some subject areas. 2)The younger the homemaker is and the higher her educational level is, the more cooperatively the couple plan in family life. 3)The family of which homemaker is younger and more educational tends to plan significantly, specifically and flexibly in family life.

• Journal of Applied Reliability
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• v.4 no.1
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• pp.15-26
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• 2004

Life test is performed to set a confidence (lower) limit on the mean or median life of items if the number of failures at the end of the fixed time t does not exceed a given number c. Gupta(1962) propose a sampling plan for truncated life tests when the life distribution of an item is normal or lognormal distribution. In this paper, based on the result of Gupta(1962), we propose a sampling plan for failure rate test when an item has normal or lognormal life distribution. We assume that the shape parameter is known while the location parameter is unknown.

• Journal of Korean Society for Quality Management
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• v.26 no.2
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• pp.27-38
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• 1998

Consider a life testing experiment in which multiple two-component shared parallel systems are put on test, and the test is terminated at a specified number of system failures. The bivariate data obtained from such a system-level life testing can be classified into three classes: 1) the case of failed two components with known failure times, 2) the case of censored two components, and 3) the case of one censored component and the other failed component of which the failure time might be known or unknown. Under this censoring scheme and the assumption of Freund's bivariate exponential life distribution, the maximum likelihood estimators are obtained. Results of comparative studies based on Monte Carlo simulation are presented.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.1
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• pp.147-152
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• 2005

The exhaust system of automobile is faced with random or spectrum types of fatigue loads during usage life and so needs to be closely estimated for quality and performance to have enough certainty on design endurance lift during preliminary design process. Structural operation conditions, operation load history, property of material and manufacturing process etc. should be considered by performing experiment approach. Using the software program for predicting fatigue life quickly and exactly in preliminary design stage saves plenty of time and cost generated by fatigue tests. In this paper, fatigue life prediction was performed on the basis of fatigue analysis using MSC/FATIGUE and load data from field test and the life of development items was estimated and compared through the results.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.47
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• pp.1-10
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• 1998

Testing high reliability devices under nomal operating condition is difficult, because the devices are not likely to fail in the relatively short time available for tests. For most applications it is necessary to accelerate the causes of failure by increasing a stress above its nomal value. Previous accelerated life test(ALT) plans have shown how to find optimum allocation, lowest stress and sample size subject to minimizing the variance of mean life estimator. In these ALT plans, the highest acceptable test-stress was assumed to be specified in advance by the experimenter but there is no guidance for selecting it. This assumption is, however, inappropriate for many applications. Testing devices at too-high stress levels can invalidate the extrapolation model, or introduce failure mechanisms that are not anticipated under nomal operating conditions. In this paper, we propose new 4:2:1 compromise plans using Min-Max method to minimize this risk and present minimized test-stress levels(max, middle, min), and find sample allocation based on Min-Max 4:2:1 compromise plans. In result, we compare previous 4:2:1 compromise plans specified maximum test-stress with Min-Max 4:2:1 compromise plans minimized maximum test-stress.

• International Journal of Advanced Culture Technology
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• v.8 no.2
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• pp.1-5
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• 2020

As the world gradually advances to an aging society, the quality of human life is valued. Among them, 'quality of sleep' is very closely related to quality of life. Recently, Korea expanded health insurance coverage for "sleep disorders". Particularly, as the number of sleep multiple tests and prescriptions for sleep aids has increased rapidly, much attention has been focused on the related medical service environment. Therefore, this study looked at an in-depth interview of 11 hospitals to see what treatment delivery system is being established when the government applies health insurance for 'sleep disorders'. In conclusion, the organizations with the most average number of sleep polyp tests per day were found to have more sleep polyp labs (hardware) and more full-time specialists. Also, the polysomnography lab (hardware) and the specialist's full-time status (software) did not necessarily result in a "positive pressure regulator prescription" that can solve "sleep apnea" caused by "sleep ailments". Rather, it was found that the number of days of sleep multiple laboratories (hardware), the number of full-time specialists (software) or the specialty majors (software) had a greater impact. In particular, the higher the specialist's full-time personnel (software) index (=6.000), the higher the sleep-inducing agent prescription rate(=1.000), and the lower the specialist's full-time personnel (software) index (=1.000), the higher the sleep-inducer's prescription rate(= 0.010) Was low. In addition, even if the professional full-time personnel(software) index was the same (=1.000), the hospital type was lower as it was closer to the public hospital(=0.067) and higher at the specialized hospital (= 0.933). In the case of university hospitals, when the full-time specialists (software) are in the same condition (= 1.000), the frequency of use of the sleep laboratory (=1.000) and the sleep test rate (= 1.000) were all the same.

• International Journal of Reliability and Applications
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• v.17 no.1
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• pp.85-105
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• 2016

In this paper accelerated life testing is incorporated in quality control technique of acceptance sampling plan to induce early failures in high reliability products.Stress under accelerated condition can be applied in constant-stress, step-stress and progressive-stress or combination of such loadings. A ramp-stress results when stress is increased linearly (from zero) with time. In this paper optimum failure-censored ramp-stress accelerated life test sampling plan for log-logistic distribution has been formulated with cost considerations. The log-logistic distribution has been found appropriate for insulating materials. The optimal plans consist in finding optimum sample size, sample proportion allocated to each stress, and stress rate factor such that producer's and consumer's interests are safeguarded. Variance optimality criterion is used when expected cost per lot is not taken into consideration, and bilevel programming approach is used in cost optimization problems. The methods developed have been illustrated using some numerical examples, and sensitivity analyses carried out in the context of ramp-stress ALTSP based on variable SSP for proportion nonconforming.

• Journal of Korean Clinical Nursing Research
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• v.14 no.1
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• pp.25-32
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• 2008

Purpose: The purpose of this study was to examine quality of life with patients in 12 months after coronary artery bypass graft surgery, compared with general population. Method: A cross-sectional comparative study was designed. Study participants were 90 adults who had undergone CABG surgery (n=45) in experimental group and general population (n=45) in control group. The subjects were asked the questionnaire (SF-36, Short Form-36) regarding the quality of life. The data were analyzed by the SPSS 13.0 program including frequency, percentage, $x^2$ test, t-test and One-Way ANOVA. Results: There were no significant differences in the quality of life between two groups including physical functioning (t=-.938, p=.351), role-physical limitation (t=-.322, p=.748), bodily pain (t=-.938, p=.351), general health (t=-.1418, p=.888), vitality (t=-.816, p=.417), social functioning (t=.720, p=.474), role-emotional limitation (t=-.710, p=.479), mental health (t=-.431, p=.667). Conclusion: Even though patients in experimental group had operation experience, the quality of life examined on the time of 1 year after bypass surgery is similar in that of general population. We suggest the study change the design as examination of quality of life before and after coronary artery bypass graft surgery.

• Child Health Nursing Research
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• v.25 no.2
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• pp.175-183
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• 2019

Purpose: This study was conducted to analyze physical symptom-related and life-style factors affecting suicidal ideation of senior grade students in elementary school. Methods: Physical symptom-related and life-style factors were used to investigate suicidal ideation among 663 elementary school students. From February 11 to 15, 2018, data were collected using a structured questionnaire and analyzed using the $x^2$ test, Pearson correlation analysis, and logistic regression analysis in SPSS for Windows version 22.0. Results: The factors affecting suicidal ideation were gender, family structure, economic status, academic performance, exposure to school violence during the past year, physical symptoms, drinking experience, smoking experience, sleeping time, and ramen noodle consumption. The regression analysis showed that exposure to school violence during the past year (odds ratio [OR]: 102.99, 95% confidence interval [CI]: 51.19~207.19, p=.001), number of physical symptoms (OR: 1.25, 95% CI: 1.12~1.41, p=.001), drinking experience (OR: 3.17, 95% CI: 1.66~6.06, p=.001), and game and internet usage time (OR: 2.08, 95% CI: 1.08~4.01, p=.029) affected suicidal ideation. Conclusion: This study revealed that physical symptoms and life-style significantly influenced suicidal ideation. Therefore, interventions to reduce suicidal ideation in children must focus on improving children's physical symptoms and life-style.

• Journal of Family Resource Management and Policy Review
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• v.20 no.1
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• pp.23-42
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• 2016

The purpose of this study was to explore a typology of leisure participation, investigate determinants of leisure participation types, and analyze differences in life satisfaction by the types of leisure participation of the elderly. The data source for this research was the 2014 Time Use Survey conducted by the Korea National Statistical office (KNSO). The statistical methods for the analysis were mean, standard deviation, ANOVA, Duncan test, cluster analysis, and logistic regression analysis. Leisure participation were classified into five types based on five categories; social activities, religious activities, media, sports, time-spending activity. The five types were named "general", "insufficient", "religious oriented", "media oriented", and sports oriented" type. Gender, health condition were identified as important determinants for the types. Life satisfaction was different according to leisure participation type of the elderly. Religious oriented type showed the highest score of life satisfaction and media oriented type showed the lowest.