• 대한간호학회지
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• 제26권4호
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• pp.820-832
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• 1996

The average smoking rate for Adults' in our country is 40.6% : It is 74.2% for men and 5.0% for women. Particularly, the smoking rate for men is reported higher than that of men in U.S.A. or Japan. Since the first report on the association between smoking and cancer appeared, 370 thousand smokers have succeeded in smoking cessation and over 90% of them have responded that they depended on a self-help smoking cessation approach. Despite this positive evidence about self- help approaches for smoking cessation, most studies on smoking cessation have focused on evaluation of formal treatment programs that are provided by clinics. Reports on the smoking cessation process used by smokers in our country could not be found. However, it is believed that the situation in our country would be quite similar to that in U.S.A. as far as approaches to successful smoking cessation are concerned. This study was conducted to classify the smoking stage to which they smoker belong and which changing mechanisms could be included at each changing stage (precontemplation stage, comtemplation stage, action stage) with a sample of 155 college students between 20 and 29 years old. And it also identified which variables related both to smoking pattern and to health, which ones were significantly discriminating in the changing stages. From the results of the data analysis it was found that Self-Determination is the most influential variable as one of the changning mechanisms which can discriminate three changing stages. And as the next significant mechanisms were Reinforcement, Dramatic Relief, Cognitive Restructuring, Helping Relationship, and Information Management in that order. Among variables related to the smoking pattern, years of regular smoking, whether smoking is continued or not even when they are sick, the number of attempts to stop smoking, number of cigarettes smoked per day, and whether they have smoked over 100 cigarettes up to now, but not the time of the first cigarette after waking-up, were the significant factors to descriminate changing stages. It was confirmed that among variables related to health that, perceived control for health, confidence of health maintence ability, and self confidence in smoking cessation, were significant variables in determinating changing stages. The most influential variables among them was self-confidence in smoking cessation. Conclusively, it was shown that smoking cessation is the process of attempting to change smoking habits through the various changing processes. Also it can be shown that a few factors smoking habit, self-confidence of smoking cessation, and belief in self control of his /her health, were influential in discriminating the changing stages of the smoking habit.

• 품질경영학회지
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• 제42권2호
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• pp.199-208
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• 2014

Purpose: This paper explains how to obtain the Bayes estimates of the whole launch vehicle and of a vehicle stage, respectively, for a newly developed expendable launch vehicle. Methods: We determine the parameters of the beta prior distribution using the upper bound of the 60% Clopper-Pearson confidence interval of failure probability which is calculated from previous launch data considering the experience of the developer. Results: Probability that a launch vehicle developed from an inexperienced developer succeeds in the first launch is obtained by about one third, which is much smaller than that estimated from the previous research. Conclusion: The proposed approach provides a more conservative estimate than the previous noninformative prior, which is more reasonable especially for the initial reliability of a new vehicle which is developed by an inexperienced developer.

• Communications for Statistical Applications and Methods
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• 제7권1호
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• pp.297-312
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• 2000

A three stage sampling procedure designed to estimate the difference betweentwo normal means is proposed and evaluated within a unified decision-theoretic framework. Both point and fixed-width confidence interval estimation are combined in a single decision rule to make full use of the available data. Adjustments to previous solutions focusing on only one of the latter objectives are indicated. The sensitivity of the confidence interval for detecting shifts in true mean difference is also investigated Numerical and simulation studies are presented to supplement the theoretical results.

• Journal of the Korean Data and Information Science Society
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• 제24권6호
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• pp.1439-1448
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• 2013

확률화 블록계획법이나 교차된 이원분류표에 대한 분산분석과 오차제곱합의 성질은 널리 알려져있다. 본 논문에서는 인자에 따른 수준에 또 다른 인자들이 내포되어 있는 지분계획 특히 이단계 지분계획에 대하여 구조적 특징을 설명하고 오차제곱합의 성질에 대하여 살펴보았다. 또한 이단계 지분계획의 활용으로 크로스오버 계획을 소개하고 생물학이나 약학 등의 분야에서 많이 사용되는 동등성 검정의 신뢰구간 구축에 대하여 설명하였고 실제자료와 SPSS 통계 페키지를 이용하여 분석함으로서 응용성을 부각시켰다.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제16권1호
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• pp.60-64
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• 2010

비 트랜잭션 데이터를 대상으로 연관 규칙을 도출하기 위해서, 데이터의 속성들을 구간화하는 기법들이 활발하게 연구되었다. 이러한 기존의 연구들은 구간화 단계에서 구간 범위의 변화에 따른 연관 규칙의 신뢰도 변화를 반영하지 않고, 구간화 단계와 연관 규칙을 도출하는 단계들을 독립적으로 수행하였다. 이로 인해 속성들의 구간이 부적절하게 설정되고, 이 결과 높은 신뢰도를 갖는 연관 규칙들이 최종 결과에서 누락된다. 따라서 본 논문에서는 속성들을 구간화하는 단계와 연관 규칙들을 도출하는 단계를 병합하여 동시에 수행함으로써, 가장 신뢰도가 높은 연관규칙들을 도출할 수 있는 구간을 설정하는 방안을 제안한다. 이를 위해서 연관 규칙의 우변의 속성들을 대상으로 계층적 클러스터링을 수행하고, 각 클러스터들에 대해서 특성 분석을 수행한다. 실험 결과, 제안하는 기법은 기존의 기법들에 비해서 높은 신뢰도를 갖는 연관 규칙들을 발견하는 것으로 나타났다.

• 응용통계연구
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• 제26권4호
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• pp.581-594
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• 2013

집단축차설계법은 중간분석을 실시하여 임상시험용 의약품의 유효성 또는 무용성이 조기에 발견되면 임상시험을 조기에 종료할 수 있는 시험설계법이다. 적응적 설계법은 중간분석 결과를 이용하여 시험설계를 변경하거나, 확률적으로 독립인 두개의 임상시험 결과를 결합하는 등 다양한 적응법으로 임상시험의 설계를 수정할 수 있는 시험설계법이다. 집단축차설계법과 적응적 설계법에서 주요하게 고려할 점은, 시험 전체적으로 제1종 오류를 적절히 분배하고 통제하여 임상시험 전체의 일관성을 유지하도록 하는 것이다. 반복측정자료 또는 경시적자료의 통계적 모형이 고려되는 경우에는 통계적 추론이 더욱 복잡하고 어려워진다. Lee 등 (2002)에서는 반복측정치를 가지는 임상시험에서 집단축차설계에서 미리 정한 기준에 의하여 임상시험이 종료된 후, 독립증분과 단계적 순서관계를 고려한 신뢰구간 추정법을 제안한 바 있다. 본 연구는 Lee 등 (2002)를 적응적 설계로 확장하였다. 적응법을 실시한 전과 후의 임상시험을 확률적으로 독립인 관계로 정의하는 검정통계량을 유도하여 적응적 집단축차검정법이 가능하게 하였다. 또한, 임상시험이 종료된 후 단계적 순서관계를 고려한 신뢰구간 추정법을 제안하였으며, 모의실험을 통하여 그 안정성을 확인하였다.

• 산업공학
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• 제22권3호
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• pp.214-222
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• 2009

In the early design stage, system reliability must be estimated from life testing data at the component level. Previously, a point estimate of system reliability was obtained from the unbiased estimate of the component reliability after assuming that the number of failed components for a given time followed a binomial distribution. For deriving the confidence interval of system reliability, either the lognormal distribution or the normal approximation of the binomial distribution was assumed for the estimator of system reliability. In this paper, a new estimator is used for the component level reliability, which is biased but has a smaller mean square error than the previous one. We propose to use the beta distribution rather than the lognormal or approximated normal distribution for developing the confidence interval of the system reliability. A numerical example based on Monte Carlo simulation illustrates advantages of the proposed approach over the previous approach.

• Communications for Statistical Applications and Methods
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• 제8권1호
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• pp.127-135
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• 2001

In this paper, we consider a simple method for testing the assumption of independent censoring on the basis of a Cox proportional hazards regression model with a time-dependent covariate. This method involves a two-stage sampling in which a random subset of censored observations is selected and followed-up until their true survival times are observed. Lee and Wolfe(1998) proposed an adjusted estimate of the survivor function for the dependent censoring under a proportional hazards alternative. This paper extends their result to obtain a bootstrap confidence interval for the adjusted survivor function under the dependent censoring. The proposed procedure is illustrated with an example of a clinical trial for lung cancer analysed in Lee and Wolfe(1998).

• 대한산업공학회지
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• 제43권2호
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• pp.147-153
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• 2017

In order to demonstrate a target reliability with a specified confidence level, a new two-stage Bayesian Reliability Demonstration Test (RDT) plans that is known to be more effective than a corresponding single-stage one is proposed and developed by Bayesian framework with beta prior distribution for Weibull life time distribution. A numerical example is provided to illustrate the proposed RDT plans and compared with other non-Bayesian and Bayesian plans. Comparative results show that the proposed Bayesian two-stage plans have some merits in terms of required and expected testing time and probability of acceptance.

• 한국수학교육학회지시리즈A:수학교육
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• 제55권3호
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• pp.317-334
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• 2016

Knowledge and data interpretation on statistical estimation was important to have statistical literacy that current curriculum was said not to satisfy. The author investigated mathematics teachers' MKT on statistical estimation concerning interpretation of confidence interval by using questionnaire and interview. SMK of teachers' confidence was limited to the area of textbooks to be difficult to interpret data of real life context. Most of teachers wrongly understood SMK of interpretation of confidence interval to have influence upon PCK making correction of students' wrong concept. SMK of samples and sampling distribution that were basic concept of reliability and confidence interval cognized representation of samples rather exactly not to understand importance and value of not only variability but also size of the sample exactly, and not to cognize appropriateness and needs of each stage from sampling to confidence interval estimation to have great difficulty at proper teaching of statistical estimation. PCK that had teaching method had problem of a lot of misconception. MKT of sample and sampling distribution that interpreted confidence interval had almost no relation with teachers' experience to require opportunity for development of teacher professionalism. Therefore, teachers were asked to estimate statistic and to get confidence interval and to understand concept of the sample and think much of not only relationship of each concept but also validity of estimated values, and to have knowledge enough to interpret data of real life contexts, and to think and discuss students' concepts. So, textbooks should introduce actual concepts at real life context to make use of exact orthography and to let teachers be reeducated for development of professionalism.