• Journal of the Korean Statistical Society
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• 제22권2호
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• pp.147-157
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• 1993

In the survivla analysis the problem of estimating mean residual life function (MRLF) under random censoring is very important. In this paper we propose and study a nonparametric estimator of MRLF, which is a functional form based on the estimator of the survival function due to Susarla and Van Ryzin (1980). The proposed estimator is shown to be better than some other estimators in terms of mean square errors for the exponential and Weibull cases via Monte Carlo simulation studies.

• Journal of the Korean Statistical Society
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• 제32권2호
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• pp.163-174
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• 2003

We propose a test for independence of bivariate censored data under univariate censorship. To do this, we first introduce a process defined by the difference between bivariate survival function estimator proposed by Lin and Ying (1993) and the product of the product-limit estimators (Kaplan and Meier, 1958) for the marginal survival functions, and derive its asymptotic properties under the null hypothesis of independence. We propose a Cramer-von Mises-type test procedure based on the process . We conduct simulation studies to investigate the finite-sample performance of the proposed test and illustrate the proposed test with a real example.

• 품질경영학회지
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• 제22권1호
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• pp.169-178
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• 1994

Nonparametric tests for comparing two treatments when data are subject to unequal patterns of censorship are discussed. Best precedence test proposed by Slud can be viewed as a nice alternative test comparing with weighted log-rank tests, not to mention the advantage of short experimental period. This research revises some missing parts of Slud's test and examines the asymptotic power of it under the nonproportional hazard alternatives through the simulation. The simulation studies show best precedence test has reasonable power in the sense of robustness under nonproportional hazard alternatives and could be recommended at such situation.

• 대한수학회보
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• 제40권2호
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• pp.269-279
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• 2003

We prove an empirical LIL for the Kaplan-Meier integral process constructed from the random censorship model under bracketing entropy and mild assumptions due to censoring effects. The main method in deriving the empirical LIL is to use a weak convergence result of the sequential Kaplan-Meier integral process whose proofs appear in Bae and Kim [2]. Using the result of weak convergence, we translate the problem of the Kaplan Meier integral process into that of a Gaussian process. Finally we derive the result using an empirical LIL for the Gaussian process of Pisier [6] via a method adapted from Ossiander [5]. The result of this paper extends the empirical LIL for IID random variables to that of a random censorship model.

• 한국산업정보학회논문지
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• 제5권2호
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• pp.62-69
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• 2000

이 논문은 임의중단 표본을 이용하여 entropy에 대한 두 개의 버클리-제임스(Buckley-James)형 추정량을 제안한다. 제안된 추정량의 소표본 특징을 조사하기 위하여 컴퓨터 모의실험을 실시하였다. 이 때 사용된 분포는 증가위험률, 상수위험률, 감소위험율을 갖는 분포를 가정하였고, 실제의 자료를 이용하여 분석하는 예를 보인다.

• Journal of the Korean Data and Information Science Society
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• 제16권4호
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• pp.889-898
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• 2005

In this paper we propose a new estimator of relative odds ratio in the two-sample case of proportional odds model under censorship. Also, we show that the estimator consistent and asymptotically normal by using martingale-representation. The efficiency of the proposed is assessed through a simulation study.

• 한국비블리아학회지
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• 제15권1호
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• pp.193-216
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• 2004

본 연구는 도서관 봉사가 추구하는 지적자유에 대한 법률적 기반과 금서 또는 유해도서로 판정된 자료를 한국과 미국을 중심으로 시대별로 나누어 파악하였다. 또한 미국에서 금서조치를 주도하는 종교적 집단과 정치적 우익집단에 대하여 살펴보았으며, 금서조치로부터 지적자유를 보호하기 위하여 노력하는 미국도서관협회 산하 각종 단체의 노력에 대하여 알아보았다. 한편, 한국과 미국에서 금서로 판정된 대법원의 판례를 살펴봄으로써 금서로 인정되는 음란물의 헌법적 판정 여부와 판정기준 등에 대하여 알아보았다. 인터넷과 게임 등으로 대변되는 멀티미디어 시대에는 음란물로 인해 금서로 판정되는 경우가 많이 있었다. 특히 미국에서는 성인물과 청소년용의 도서를 엄격히 구분하고 있었으며, 음란물로부터 청소년을 보호하려는 장치를 많이 제공하고 있었다. 우리나라에서도 음란물로부터 청소년을 보호하기 위한 적극적인 대처방안이 필요할 것이다.

• 한국멀티미디어학회논문지
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• 제23권3호
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• pp.430-439
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• 2020

The government of the Republic of Korea has introduced SNI blocking method since February 2019 to block illegal sites. Currently, this policy has been considered as a controversial policy in South Korea therefore, about 270,000 South Koreans have been calmed down by and the presidential office petition because people believe that blocking https by SNI would invasion of privacy and freedom of use of the Internet. As soon as the SNI blocking method was used, the bypass method was opened to the Internet, causing side effects. In this study, identifies the development of Internet blocking technology and the development of new technology that bypasses the technology. It also examines Internet censorship in other countries and identifies problems in blocking technology. Through this study would present policy suggestions and technical methodologies for sound Internet use.

• Journal of the Korean Statistical Society
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• 제26권2호
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• pp.231-243
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• 1997

In this paper we investigate weak convergence of the intergral processes whose index set is the non-compact infinite time interval. Our first goal is to develop the empirical central limit theorem as random elements of [0, .infty.) for an integral process which is constructed from iid variables. In developing the weak convergence as random elements of D[0, .infty.), we will use a result of Ossiander(4) whose proof heavily depends on the total boundedness of the index set. Our next goal is to establish the empirical central limit theorem for the Kaplan-Meier integral process as random elements of D[0, .infty.). In achieving the the goal, we will use the above iid result, a representation of State(6) on the Kaplan-Meier integral, and a lemma on the uniform order of convergence. The first result, in some sense, generalizes the result of empirical central limit therem of Pollard(5) where the process is regarded as random elements of D[-.infty., .infty.] and the sample paths of limiting Gaussian process may jump. The second result generalizes the first result to random censorship model. The later also generalizes one dimensional central limit theorem of Stute(6) to a process version. These results may be used in the nonparametric statistical inference.

• Communications for Statistical Applications and Methods
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• 제26권5호
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• pp.445-461
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• 2019

It is possible that data are not always fitted with sufficient precision by the existing distributions; therefore this article presents a methodology that enables the use of families of asymmetric distributions as alternative probabilistic models for survival analysis, with censorship on the right, different from those usually studied (the Exponential, Gamma, Weibull, and Lognormal distributions). We use a more flexible parametric model in terms of density behavior, assuming that data can be fit by a distribution of stable distribution families considered unconventional in the analyses of survival data that are appropriate when extreme values occur, with small probabilities that should not be ignored. In the methodology, the determination of the analytical expression of the risk function h(t) of the $L{\acute{e}}vy$ distribution is included, as it is not usually reported in the literature. A simulation was conducted to evaluate the performance of the candidate distribution when modeling survival times, including the estimation of parameters via the maximum likelihood method, survival function ${\hat{S}}$(t) and Kaplan-Meier estimator. The obtained estimates did not exhibit significant changes for different sample sizes and censorship fractions in the sample. To illustrate the usefulness of the proposed methodology, an application with real data, regarding the survival times of patients with colon cancer, was considered.