• Journal of the Korean Data and Information Science Society
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• v.23 no.3
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• pp.487-494
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• 2012

This paper discusses a method for getting a basis set of estimable functions of model parameters in a two-way fixed effects model. Since the fixed effects model has more parameters than those that can be estimated, model parameters are not estimable. So it is not possible to make inferences for nonestimable functions of parameters. When the assumed model of matrix notation is reparameterized by the estimable functions in a basis set, it also discusses how to use projections for the estimation of estimable functions.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.4
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• pp.457-463
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• 2012

The basilar membrane (BM), one of organs of cochlea, has the specific positions of the maximum amplitude at each of related frequencies. This phenomenon is due to the geometry of BM. In this study, as the part of the research for the development of fully implantable artificial cochlea which is based on polymer membrane, parametric studies are performed to suggest the desirable artificial basilar membrane model which can detect wider range of frequency separation. The vibro-acoustic characteristics of the artificial basilar membrane are predicted through finite element analysis using commercial software Abaqus. Simulation results are verified by comparing with experimental results. Various geometric shapes of the BM and residual stress effects on the BM are investigated through the parametric study to enable a wider detectable frequency separation range.

• The korean journal of orthodontics
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• v.27 no.1
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• pp.157-171
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• 1997

This study was conducted to see the effect of TiN ion-plating on the bond strength of orthodontic bracket. Three stainless-steel brackets with different base types were chosen; when TiN ion-plated brackets and non iorrplated brackets were bonded to the teeth, initial and long-term bond strength were measured, The observations oi bonding surface and failure sites through the scanning electron microscope were analysed and compared. The summary of this study was as follows; ${\cdot}$ When TiN ion-plating was not applied, the Micro-Loc type was the highest in bond strength atter 24 hours as $5.89{\pm}1.77$ MPa, followed by $4,27{\pm}1.12MPa$ for Foil Mesh type and $2.64{\pm}0.58MPa$ for Undercut type(P<0.05). ${\cdot}$ Under TiN ion-plating, the bond strength after 24 hours showed: Micro-Loc type $-6.26{\pm}1.51MPa$, Foil Mesh type $-7.45{\pm}2.01MPa$, Undercut type $-2.93{\pm}0.84MPa$. Unlike in the case of non ion-plating, Foil Mesh type showed a higher strength than Micro-Loc type, with Undercut type still showing the lowest bond strength(P<0.05). The bond strength, after 24 hours, increased in case of ion-plated in all 3 types, but a significant increase was shown only in Foil Mesh type(P<0.001). ${\cdot}$ Under a long-term immersion, regardless of ion or non ion-plating, bond strength in general increased over the initial bond strength(one day), with more stability. ${\cdot}$ Through scanning electron microscopic observation of bonding surface, it was found that, regardless of the bracket base type or the application of ion-plating, the resin was thoroughly spreaded into bracket base to form a solid bonding surface between the bracket and the tooth. This was also true in case of a long-term immersion. ${\cdot}$ The scanning electron microscopic observation of failure sites revealed diverse failure patterns.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.68.1-68.1
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• 2010

염료감응형 태양전지에서 가능한 광전자의 이동경로에 대해 살펴보면 빛 에너지를 흡수한 루테늄계 염료는 기저상태에서 여기상태로 전이한 후 광전자의 반도체 전도띠로 전자주입이 이루어진다. 이러한 전자 중 일부는 반도체산화물의 트랩으로의 전이와 트랩에서 염료 기저상태로의 전이가 일어나고 일부 전자는 전해질의 이온종 또는 산화된 염료와 재결합하는 현상이 일어난다. 본 연구에서는 이러한 전자의 재결합을 막고자 p형 반도체인 NiO paste를 제작하여 $TiO_2$ 광전극 층 위에 코팅하였다. 코팅된 NiO 층은 홀수용체로서 염료에 전자를 제공해 주는 역할과 동시에 $TiO_2$ 가전도대로 이동되었던 전자들이 염료의 기저상태의 홀이나 전해질로의 전자 유입이 이루어지는 전자의 재결합을 막는 방벽의 역할을 동시에 하게 된다. 제작된 염료감응형 태양전지 셀의 에너지 변환효율 특성을 알아보기 위하여 1000 W Xe Arc Lamp와 Air Mass 1.5, filter가 장착된 Thermo-Preal (USA) Solar simulator system을 사용하여 개방전압 (Voc), 광전류 (Isc), fill factor (FF), 에너지변환 효율 (${\eta}$)을 조사하였으며 광학현미경을 통해 염료의 흡착 정도를 비교해 보았다. NiO의 코팅 두께나 NiO 나노입자 크기에 따라 염료감응형태양전지에서 에너지변환효율에 미치는 영향을 조사하였다. NiO가 코팅되지 않은 $TiO_2$ 광전극과 비교해 볼 때 NiO 코팅시 Voc와 Isc의 증가로 인해 에너지변환효율이 20% 이상 향상되는 것을 볼 수 있었다.

• Proceedings of the Korean Magnestics Society Conference
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• 1997.11a
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• pp.40-41
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• 1997

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.659-662
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• 2000

다양한 보간 기법을 정리해 보고 이를 통해서 기존의 보간 기법의 한계를 고찰해 본다. 보간의 효율성과 보간 결과 영상의 화질과는 Trade off 관계가 있으며, 이를 적절한 수준에서 결정하는 것은 중요한 문제이다. 본 논문에서는 Quadratic B-spline을 기저 함수로 하는 윤곽보존형 보간 필터를 사용한 영상확대 알고리즘을 제안한다. Unser의 Cardinal Cubic spline함수에 비해 적은 하드웨어만으로도 이상적인 저역 통과 필터의 특성을 가지며, 입력영상의 윤곽의 방향성을 고려한 적응적인 보간 기법의 적용으로 화질이 우수한 영상확대 알고리즘을 제안한다.

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.476-478
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• 2008

분산 전원의 기저 전원으로써 개발된 일체형 원자로(REX-10)를 지역에너지시스템에 도입하고 안정적인 운전을 하기 위해서 본 논문은 전압원형 인버터를 설계하고 일체형 원자로가 변동 없이 정출력을 하도록 지역에너지시스템의 전력 변동 상황을 모니터링하여 제어하는 모델을 개발하였다. 제안된 모델의 효용성을 확인하기 위해서 PSCAD/EMTDC를 사용하였다.

• Proceedings of the Korean Statistical Society Conference
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• 2003.10a
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• pp.285-288
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• 2003

신용위험 관리에서 필수적인 방법론이 스코어 카드이며 이를 작성하는 데에 있어서 널리 쓰이는 방법 중의 하나가 로지스틱 회귀분석이다. 본 논문에서는 로지스틱 회귀 방법에 기초한 스플라인 방법론을 소개하고자 한다. 최종 스코어 카드는 연속형 변수를 범주형 변수화 하므로 조각 선형 스플라인을 채택하였다. 모의 실험을 통하여 제안된 방법의 성 능을 규명 하였다.

• Applied Microscopy
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• v.22 no.2
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• pp.84-96
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• 1992

This study was carried out to examine the $H^+$ transport mechanism by observing the properties of cellular membrane having an ${\alpha}$ type of carbonic anhydrase (CA)-containing cells in turtle urinary bladder. The urinary bladder consists of a heterogenous population of cells. As a result of fine observation with traditional thin-section electron microscopy. the bladder epithelium has three different cell types on mucosal surface. They are a basal cell, a granular cell and a third type of CA-rich cell. The CA-rich cells are divided into two distinct smaller groups within them and called them ${\alpha}$ type and ${\beta}$ type of CA cells. The ${\alpha}$ type of CA cells are responsible for the proton secretion using the proton pumps on the apical plasma membrane, while the ${\beta}$ type of CA cells secrete bicarbonate via an oppositely-directed proton pumps in their basolateral plasma membrane. After performing the freeze-fracture technique, it was shown that there were distributed a large number of intramembranous particles having a special structure on the apical membrane of ${\alpha}$ type of CA-rich cells in the process of their $H^+$ secretion. In turtle bladder ${\alpha}$ type of CA-rich cells, this particle was the only prominent structure in the apical membrane. These intramembrane rod-shaped particles probably represent the integral membrane components of the proton pump. This result may explain that carbonic anhydrase within epithelial cell of urinary bladder takes part in formation of $H^+$ and bicarbonate, that active transport of $H^+$ is done, and that the reabsorption of bicarbonate suggests transport mechanism containing $H^+$ secretion. However, it seems that more studies are required for considering their regular transport pathway.

• Resources Recycling
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• v.26 no.2
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• pp.46-55
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• 2017

In this study, the design methodology of Radial Basis Function Neural Networks is developed with the aid of Laser Induced Breakdown Spectroscopy and also applied to the practical plastics sorting system. To identify black plastics such as ABS, PP, and PS, RBFNNs classifier as a kind of intelligent algorithms is designed. The dimensionality of the obtained input variables are reduced by using PCA and divided into several groups by using K-means clustering which is a kind of clustering techniques. The entire data is split into training data and test data according to the ratio of 4:1. The 5-fold cross validation method is used to evaluate the performance as well as reliability of the proposed classifier. In case of input variables and clusters equal to 5 respectively, the classification performance of the proposed classifier is obtained as 96.78%. Also, the proposed classifier showed superiority in the viewpoint of classification performance where compared to other classifiers.