• Journal of the Korean Statistical Society
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• 제11권2호
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• pp.77-87
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• 1982

The choice if constants that define a life testing procedure is considered in terms of the test termination time (censoring time) and the number of items to be tested subject to a given range of variance of the expected life time, where the failure time of life testing is exponentially distributed.

• 한국해양공학회지
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• 제24권6호
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• pp.97-102
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• 2010

This paper deals with the variability of short term creep rupture time based on previous creep rupture tests and the statistical methodology of the creep life prediction. The results of creep tests performed using constant uniaxial stresses at 600, 650, and $700^{\circ}C$ elevated temperatures were used for a statistical analysis of the inter-specimen variability of the short term creep rupture time. Even under carefully controlled identical testing conditions, the observed short-term creep rupture time showed obvious inter-specimen variability. The statistical aspect of the short term creep rupture time was analyzed using a Weibull statistical analysis. The effect of creep stress on the variability of the creep rupture time was decreased with an increase in the stress level. The effect of the temperature on the variability also decreased with increasing temperature. A long term creep life prediction method that considers this statistical variability is presented. The presented method is in good agreement with the Lason-Miller Parameter (LMP) life prediction method.

• Communications for Statistical Applications and Methods
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• 제10권3호
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• pp.679-694
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• 2003

The purpose of this paper is to develop the Index of Balanced Life from the Korean life style. This paper presents How Koreans live for 24 hours a day, generally. The Index of Life Style is composed of necessary life, duty life and leisure life. Specifically, this paper considers moving time of activity between indexes of balanced life. We suggest that there is a difference among the characteristics, i.e., a sex, week, state of student and region that are explained by analyzing the exploratory data. Thereafter we obtain the statistical inference from each characteristic table.

• 응용통계연구
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• 제2권2호
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• pp.61-78
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• 1989

정상조건에서 수명이 상당히 긴 개체의 생명검사(Life Test)를 현실적으로 수행하기 위하여 제안된 충격생명검사에 관하여 고찰하였다. 생명검사의 결과로 얻는 자료의 통계적 분석을 위하여 이미 제안된 모형의 검토와 이들을 일면 포함하는 모형을 제시하고 그에 따르는 통계적 추론 과정을 최대우도추정법과 가중최소자승법을 사용하여 토의하였다. 한편 검사를 계획할 때 발생하는 실험설계의 문제를 검토하고 단순 계단적 충격검사에서 잘려진 자료(Consored Data)를 포함한 경우를 연구하였다.

• 응용통계연구
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• 제31권1호
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• pp.41-65
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• 2018

우리나라의 경우 선진국에 비해 짧은 기간 동안 사망률 개선이 급속히 이루어짐에 따라 사망률 예측에 있어 모형의 선택뿐만 아니라 시계열 이용기간의 선정 또한 중요한 고려사항이 될 수 있다. 따라서 본 연구에서는 시계열 이용기간의 선택 관점에서 회귀모형을 이용하는 방법을 제안하였다. 또한 Lee-Carter (LC) 모형, LC류 (Lee-Miller (LM), Booth-Maindonald-Smith (BMS)) 그리고 비모수 모형(functional data model (FDM), Coherent FDM)을 토대로 시계열 이용기간을 다르게 적용할 경우 어떠한 문제가 발생되며, 연령별 사망률과 기대수명 예측력에 어떠한 차이를 보이는지 살펴보았다. 분석결과를 바탕으로 5개의 모형별 2030년까지 남녀의 연령별 사망률과 예측기대수명을 작성하고 통계청(Korean Statistical Information Service; KOSIS)에서 제공하는 장래 연령별 사망률과 기대수명과 비교하였다.

• Communications for Statistical Applications and Methods
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• 제6권2호
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• pp.423-432
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• 1999

Accelerated life testing of product is commonly used to reduced test time and costs. In this papers is considered when the product is a two component system with lifetimes following the bivariate exponential distribution of Sarkar(1987) using inverse power rule model. Also we derived the maximum likelihood estimators of parameters for asymptotic normality. We compare the mean square error of the proposed estimator for the life distribution under use conditions stree through Monte Carlo simulation.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.57-61
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• 1999

Electrical stress makes insulating materials aged finally resulting in the dielectric failure. It becomes more and more important to recognize the degree of aging and the life time of the insulating materials since it is directly concerned with the reliability of the insulation system. In this paper, the life time of the Cross-linked Polyethylene(XLPE), the insulation layer in the 154kV-grade power cable, is expected and calculated using statistical and mathematical methods. The simulated results are compared with experimental ones and the life exponent of the material is obtained.

• 가족자원경영과 정책
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• 제20권1호
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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.

• Communications for Statistical Applications and Methods
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• 제17권1호
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• pp.89-98
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• 2010

In this paper, a two-stage group sampling plan based on the time truncated life test is proposed for the Weibull distribution. The design parameters such as the number of groups and the acceptance number in each stage are determined by satisfying the producer's and consumer's risks simultaneously when the group size and the test duration are specified. The acceptable reliability level is expressed by the ratio of the true mean life to the specified life. It was demonstrated from the comparison with single-stage group sampling plans that the proposed plan can reduce the average sample number or improve the operating characteristics.

• 한국생활과학회지
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• 제15권6호
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• pp.985-997
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• 2006

In this study, we grasped the life time structure according to working woman's income using '2004 life time research' of Korea National Statistical Office. Concrete results are shown as follows. First, inspecting the difference of individual characteristic according to income, young women who have higher education level and larger house area had acquired more income. Second, in case of the difference of life time according to income, there was no difference of individual support time, while there was statistically significant difference of working hours, household affairs, leisure time and moving hours. Third, inspecting the individual time of working, household affairs, bringing up and leisure according to income, there was statistically significant difference by age, education level, sense of time oppression, and fatigue cognition. This individual difference was revealed more strongly in medium to low-ranked group.