• Communications for Statistical Applications and Methods
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• 제21권2호
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• pp.115-124
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• 2014

In this paper we derive a Berry-Esseen type bound for the kernel density estimator of a random left truncated model, in which each datum (Y) is randomly left truncated and is sampled if $Y{\geq}T$, where T is the truncation random variable with an unknown distribution. This unknown distribution is estimated with the Lynden-Bell estimator. In particular the normal approximation rate, by choice of the bandwidth, is shown to be close to $n^{-1/6}$ modulo logarithmic term. We have also investigated this normal approximation rate via a simulation study.

• Journal of the Korean Data and Information Science Society
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• 제8권1호
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• pp.49-58
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• 1997

We consider the quantile function for the bootstrapped product limit estimate under left truncation and right censoring model and show its weak convergence. We also obtain bootstrapped confidence bands for the quantile function.

• Journal of the Korean Data and Information Science Society
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• 제6권2호
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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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• 제26권3호
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• pp.333-354
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• 1997

Computational algorithms to calculate M-estimators and rank estimators of regression parameters from left-truncated and right-censored data are developed herein. In the case of M-estimators, new statistical methods are also introduced to incorporate leverage assements and concomitant scale estimation in the presence of left truncation and right censoring on the observed response. Furthermore, graphical methods to examine the residuals from these data are presented. Two real data sets are used for illustration.

• Communications for Statistical Applications and Methods
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• 제12권3호
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• pp.807-818
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• 2005

In this paper we propose an estimation method for regression quantiles with left-truncated and right-censored data. The estimation procedure is based on the weight determined by the Kaplan-Meier estimate of the distribution of the response. We show how the proposed regression quantile estimators perform through analyses of Stanford heart transplant data and AIDS incubation data. We also investigate the effect of censoring on regression quantiles through simulation study.

• 한국데이터정보과학회:학술대회논문집
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• 한국데이터정보과학회 2006년도 PROCEEDINGS OF JOINT CONFERENCEOF KDISS AND KDAS
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• pp.37-37
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• 2006

• Communications for Statistical Applications and Methods
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• 제9권1호
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• pp.249-259
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• 2002

In order to estimate the mean and variance for a Normal distribution which is truncated at both right and left sides, maximum likelihood estimators based on the entire sample from the original distribution are compared with the sample mean and variance of the censored sample which is the data remaining after truncation using simulation. We found that, surprisingly, the mean squared error of the mean based on the censored data Is smaller than that of the full sample estimators.

• 정보관리연구
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• 제23권1호
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• pp.39-62
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• 1992

본(本) 연구(硏究)는 실제의 데이터 분석(分析)을 통하여 60여개의 조사(助詞)와 출현빈도는 높지만 검색(檢率)에 불필요한 320여개의 불용어(不用語)를 선정하여 좌우절단을 적용한 네 가지 유형으로 분류하고 조사(助詞)와 불용어 테이블을 구성하는 방법(方法)을 제시한다. 한글문헌에서 단어(單語)가 추출되면 조사의 효율적인 절단이 이러우지고, 한자어(漢字語)일 경우 한글로 변환되며, 2단계로 불용어제거(不用語除去) 과정을 거쳐 키워드를 선정하는 시스템을 개발한다. 여기서 추출된 키워드는 정보전문가(情報專門家)에 의해 추출된 색인어(索引語)와는 92.2%의 일치율을 보였다. 그리고 $4{\sim}6$글자로 구성된 복합어(複合語)의 경우 본(本) 연구(硏究)에서 제시한 분리방법에 의해 약 2배의 새로운 단어(單語)를 추가할 수 있었으며 그 중 58.8%가 키워드로 적합했다.

• 응용통계연구
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• 제19권3호
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• pp.395-406
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• 2006

임상시험 연구나 역학 연구에서 환자들의 예후는 흔히 생존을 추정을 통해 수량화 되곤 한다. 하지만 코호트 분석이나 완전분석에 의한 생존율 추정량들은 수년 전에 진단된 환자에 크게 의존하기 때문에 실제 생존율보다 더 낮게 추정하곤 한다. 본 연구에서는 최근의 생존정보를 잘 반영하는 생존을 추정을 위해 기간분석 방법을 통한누적한계 추정량을 제안하였고, 그 방법을 1993년 1월-1997년 12월 사이에 조사된 서울시 암등록 자료(Ahn등, 2002)에 적용하여 결과를 고찰하였다.