• Journal of the Korean Data and Information Science Society
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• 제17권3호
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• pp.999-1007
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• 2006

The semiparametric gamma frailty models have been often used for multivariate survival analysis because they give an explicit marginal likelihood. The commonly used estimation procedure is the profile likelihood method based on marginal likelihood, which provides the same parameter estimates as the EM algorithm. In this paper we show in finite samples the standard profile-likelihood method can lead to an underestimation of parameters, particularly for the frailty parameter. To overcome this problem, we propose an adjusted profile-likelihood method. For the illustration a numerical example and a small-sample simulation study are presented.

• Communications for Statistical Applications and Methods
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• 제11권3호
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• pp.455-463
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• 2004

In this paper, we derive sharp upper and lower expectation bounds on the extreme order statistics from possibly dependent random variables whose marginal distributions are only known. The marginal distributions of the considered random variables may not be the same and the expectation bounds are completely determined by the marginal distributions only.

• 대한치과의사협회지
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• 제54권5호
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• pp.328-341
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• 2016

An overall reduction in the horizontal and vertical dimensions occurs following tooth extraction and the resorption of the buccal part of the ridge is more pronounced than the lingual part. Thus, the resulting morphology of the healed alveolar ridge is often presenting with a discrepancy in bone height between the buccal and lingual aspects of the ridge. The implant with a sloped marginal configuration that is designed to match the sloped contour of the alveolar ridge provides the opportunity to maintain the buccal-lingual bone discrepancy and soft tissue around the implant. This paper introduces the OsseoSpeed TX Profile implants with sloped marginal configuration and explains the characteristics and clinical meanings of those implants.

• 대한치과기공학회지
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• 제13권1호
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• pp.9-13
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• 1991

The purpose of this study was to determine the marginal fit of recasting by used nickel-chromium metal alloys, Hi-Crown, New-Crown and CB-80. Ninety crown prosthetics were divided into eighteen groups according to new to old metal ratios. Each crown was seated on its master die and then the marginal gaps were measured under optical microscope($\times$50). All groups were showed good marginal fit, except group 3 of Hi-Crown(156$\mu$m). The results suggest that the marginal fit of Ni-Cr metal alloy casting bodies were good as without concerned to mixed ratios and metals.

• 조명전기설비학회논문지
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• 제17권6호
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• pp.54-59
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• 2003

본 논문에서는 퍼지 선형회귀분석법을 이용한 경쟁 전력시장에서의 전력의 시간별 현물가격을 예측하는 기법을 제시한다. 제안한 기법은 2002년 봄의 일주일에 대한 시간별 수요을 예측하여 본 기법의 타당성과 정확도를 검증하였다. 제안한 방법의 예측 오차는 주중의 경우 3.14%∼6.10%이며, 주말의 경우 7.04%∼8.22%로써 뉴럴 네트워크 기법을 이용한 방법과 비교하여 타당한 결과를 보였다.

• 에너지공학
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• 제7권2호
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• pp.172-179
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• 1998

본 연구에서는 복합계통의 수송능력을 평가하던 종래의 연구결과를 발견시켜,‘각 지역에 공급되는 전력이 예측된 최대부하에 대해 얼마만큼의 여유가 있는가’를 계산하는 방법을 제안한다. 각 부하모선의 수송여유에 따른 지역간 분할의 내용을 소개하며, 계산과정에서 병목선로도 탐색하도록 하였다. 그 결과 계통에서 취약한 수송여유를 보이는 부하모선의 신뢰도 향상에 관한 자료를 얻을 수 있었다. 제안한 앨고리즘을 IEEE 신뢰도 모델계통에 적용하여 그 유용성을 검증하였다.

• Journal of Korean Neurosurgical Society
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• 제42권3호
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• pp.220-223
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• 2007

We report a case of dural marginal zone lymphoma which showed the usual radiological findings resembling meningioma. A 59-year-old woman presented with headache. Initial computed tomography and magnetic resonance images showed a frontal convexity meningioma. The patient underwent a craniotomy and subtotal (simpson grade II) resection of tumor was done. Pathological examination confirmed an extranodal marginal zone B-cell lymphoma of Mucosa-Associated Lymphoid Tissue (MALT). The lesion was composed of a lymphoid mass with irregularly shaped follicles surrounded by many monomorphic small lymphocytes and a stained marginal zone for B-cell markers CD20 and CD29a. The natural history of primary CNS lymphoma and MALT type lymphoma are different. B-cell MALT lymphoma can mimic meningioma in its radiological features. Accordingly, MALT lymphoma of the CNS must be considered in the differential diagnosis of meningioma.

• Communications for Statistical Applications and Methods
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• 제11권2호
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• pp.381-397
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• 2004

The marginal likelihood has become an important tool for model selection in Bayesian analysis because it can be used to rank the models. We discuss the marginal likelihood for Poisson regression models that are potentially useful in small area estimation. Computation in these models is intensive and it requires an implementation of Markov chain Monte Carlo (MCMC) methods. Using importance sampling and multivariate density estimation, we demonstrate a computation of the marginal likelihood through an output analysis from an MCMC sampler.

• 대한교통학회지
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• 제8권1호
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• pp.17-24
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• 1990

The first-best pricing rule which achieves economic efficiency is to equate price with marginal cost. Since public transport demand is derived from some other demand, the user cost as well as the producer cost are considered in its pricing. The optimal price is derived from a derivative of the total social cost with respect to demand. In case of the bus, if there is enough capacity for demand increase, the optimal price is determined by the marginal producer cost resulting from bus sped decrease and by the marginal user cost resulting from journey time increase. Both are caused by boarding and fare collecting time of an additional passenger. Because of the budget constraints, the marginal cost pricing cannot be applied in practice. Then price discrimination as the second-best pricing is introduced. The Ramsey pricing, to charge different prices for different demand elasticities, and nonuniform prices such as travelcards can be applied. However, there is practical difficulty in implementing these prices because of great informational requirements, the costs of administration and the ease to users.

• 대한전기학회논문지:전력기술부문A
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• 제50권7호
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• pp.333-339
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• 2001

The transmission networks are not perfect conductors and a percentage of the power generated is therefore lost before it reaches the loads. This network loss effects to the cost of suppling power to consumers, and must be considered if the most efficient dispatch and location of generators and loads is to be achieved. In this paper, we propose an approximate calculation of marginal loss factors to analyze characteristics of transmission loss of KEPCO power system. These static marginal loss factors are approximately calculated based on the KEPCO's expected summer peak load data of year 2000.