• 한국시뮬레이션학회논문지
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• 제25권4호
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• pp.13-20
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• 2016

마이크로시뮬레이션 모델은 거시적 수준의 인구, 사회, 경제 변화를 각 개인과 가구 단위의 미시적 수준의 사건들로부터 기술하고자 하는 것을 목적으로 하며, 최근 OECD 국가들을 중심으로 정책 시뮬레이션 도구로서 많은 관심을 받고 있다. 마이크로시뮬레이션 모델의 활용도를 높이기 위해서는 해당 국가의 인구 구조를 잘 반영하는 인구 데이터가 필요한데, 우리는 반복비례갱신 (iterative proportional updating) 방법을 이용하여 한국 가상 인구를 생성하였다. 생성된 가상 인구 데이터의 검증을 위하여 인구센서스 집계 결과와의 오차를 계산하였으며, 가구와 인구 모두에 대해서 실제 집계 결과와 작은 오차를 보이는 것을 확인하였다.

• Journal of the Korean Data and Information Science Society
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• 제9권2호
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• pp.173-177
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• 1998

This paper presents the asymptotic relative efficiency of the nonparametric estimator relative to the parametric maximum likelihood estimator of the reliability function under the proportional hazards model of random censorship. Also we examine the efficiency loss due to censoring proportions and misson times.

• Journal of the Korean Data and Information Science Society
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• 제9권2호
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• pp.119-138
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• 1998

The case of proportional cell frequencies for the two-way cross-classification with interaction is considered. Several types of hypotheses for the general unbalanced data that are commonly used in the literature are shown, and they are written out for this particular case. A reparameterized form of the cell means model is defined to establish the reparameterized model, and orthogonal property of the model is shown using the augmented matrix and the numerator sums of squares are computed. Different ways of producing the same analysis of variance tables are shown in both orthogonal and nonorthogonal situations.

• 동력기계공학회지
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• 제7권1호
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• pp.68-73
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• 2003

The purpose of this study is to develop a new proportional pressure reducing valve and to verify the validity of a new mechanism with pressure control pin. The dynamic characteristics of the object pressure reducing valve was studied by numerical analysis of the mathematical model. Also, static and dynamic characteristics of the new pressure control valve were tested with a testing system based on the test standard.

• 품질경영학회지
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• 제17권2호
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• pp.149-157
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• 1989

A one-upper warehouse n-lower retailer inventory model is discussed. The probability distribution of demand for a given perod is independent. The inventory holding cost is proportional to the number of unsold units and the cost of shortages is proportional to the number of shortages. In the event of a shortage, units are redistributed with a cost proportional to the number of units from the retailers which are a surplus at the end of the period. The optimum stock levels are obtained and the effects of redistribution are analized.

• Communications for Statistical Applications and Methods
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• 제17권1호
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• pp.99-106
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• 2010

In this paper, we present two methods for obtaining prediction intervals for the times to failure of units censored in multiple stages in a progressively censored sample from proportional hazard rate models. A numerical example and a Monte Carlo simulation study are presented to illustrate the prediction methods.

• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2002년도 정기학술대회
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• pp.415-415
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• 2002

Proportional hazards model can be used to develop a realistic approach to determine the performance of a system. The proportional hazards model is typically applied for a group of equipments to assess the importance of factors that may influence the reliability of a system. In this paper we considered the interarrival times of a maintained system for the analysis of reliability, maintainability and availability. In order to demonstrate the proposed approach, an example is presented.

• Journal of the Korean Statistical Society
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• 제35권3호
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• pp.251-260
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• 2006

The proportional hazards model (PHM) can be associated with a non- homogeneous Markov chain (NHMC) in the sense that sample alignments in the PHM correspond to trajectories of the NHMC. As a result the partial likelihood widely used for the PHM is a probabilistic function of the trajectories of the NHMC. In this paper, we show that, as the total number of subjects involved increases, the trajectories of the NHMC, i.e. sample alignments in the PHM, converges to the solution of an ordinary differential equation which, subsequently, characterizes the almost sure limit of the partial likelihood.

• Journal of the Korean Data and Information Science Society
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• 제15권3호
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• pp.605-616
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• 2004

In this paper we consider the proportional hazard models for survival analysis in the microarray data. For a given vector of response values and gene expressions (covariates), we address the issue of how to reduce the dimension by selecting the significant genes. In our approach, rather than fixing the number of selected genes, we will assign a prior distribution to this number. To implement our methodology, we use a Markov Chain Monte Carlo (MCMC) method.

• Journal of the Korean Data and Information Science Society
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• 제15권2호
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• pp.347-353
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• 2004

We propose a simple nonparametric estimator of relative risk in the two sample case of the proportional hazards model for complete data. The asymptotic distribution of this estimator is derived using a functional equation. We obtain the asymptotic normality of the proposed estimator and compare with Begun's estimator by confidence interval through simulations.