• Journal of Electrical Engineering and Technology
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• 제10권1호
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• pp.8-17
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• 2015

This paper analyses the power flow of a three-feeder/multi-bus distribution system by a custom Generalized Power Quality Conditioner (GUPQC). The GUPQC has been realized by three voltage source converters (VSCs) coupled back-to-back through a common DC-link capacitor on the DC-side. One feeder was controlled by the shunt compensator, whereas each of the other two feeders was controlled by the proposed novel series compensator. The GUPQC has the capability to simultaneously compensate voltage and current quality problems of a multi-bus/three-feeder distribution system. Besides that, the power can be transferred from one feeder to other feeders to compensate for poor power quality problems. Extensive simulation studies were carried out by using MATLAB/SIMULINK software to establish the ability of the GUPQC to improve power quality of the distribution systems under distorted supply voltage conditions.

• Communications for Statistical Applications and Methods
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• 제21권1호
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• pp.45-60
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• 2014

We introduce a MCMC sampling for a generalized linear normal random effects model with the ordered probit link function based on latent variables from suitable truncated normal distribution. Such models have proven useful in practice and we have observed numerically reasonable results in the estimation of fixed effects when the random effect term is provided. Applications that utilize Korean Welfare Panel Study data can be difficult to model; subsequently, we find that an ordered probit model with the random effects leads to an improved analyses with more accurate and precise inferences.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2016년도 전력전자학술대회 논문집
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• pp.151-152
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• 2016

This paper presents a neutral point deviation compensating control algorithm applied to a 3-level NPC converter under generalized unbalanced ac input conditions. The neutral point deviation is analyzed with a focus on the current flowing out of or into the neutral point of the dc-link in 3-level NPC converter. The model of neutral point deviation and neutral current are also constructed. The positive and negative sequence components of the pole voltages and ac input currents are employed to accurately explain the behavior of 3-level NPC converter and its impact on neutral point deviation. This paper includes the harmonic characteristic of neutral point current under various imbalance AC operating conditions.

• 한국정보통신학회논문지
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• 제8권5호
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• pp.1028-1034
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• 2004

최근 멀티미디어 기반의 WWW(World Wide Web) 서비스를 중심으로 하는 인터넷의 사용이 일반화되면서 전 세계의 컴퓨터망에 존재하는 수많은 정보들을 취득할 수 있게 되었다. 인터넷의 사용이 일반화되고 있는 현대의 사회에서는 정확한 정보를 신속하게 취득하는 것이 중요한 문제로 대두되고 있다. 본 논문에서는 OOPL(Object-Oriented Programming Language)인 JAVA를 이용하여 검색엔진을 설계하고 최적화된 URL을 추출하여 이용자에게 제공함으로써 더욱 정확한 정보를 획득할 수 있음을 보였다. 또한 기존의 국내 제작 검색엔진들과 비교하여 제안한 시스템에서는 배드 링크율이 개선됨을 보였다.

• Communications for Statistical Applications and Methods
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• 제16권4호
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• pp.697-705
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• 2009

The Pearson chi-squared statistic or the deviance statistic is widely used in assessing the goodness-of-fit of the generalized linear models. But these statistics are not proper in the situation of continuous explanatory variables which results in the sparseness of cell frequencies. We propose a goodness-of-fit test statistic for the cumulative logit models with ordinal responses. We consider the grouping of a dataset based on the ordinal scores obtained by fitting the assumed model. We propose the Pearson chi-squared type test statistic, which is obtained from the cross-classified table formed by the subgroups of ordinal scores and the response categories. Because the limiting distribution of the chi-squared type statistic is intractable we suggest the parametric bootstrap testing procedure to approximate the distribution of the proposed test statistic.

• 한국공간구조학회논문집
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• 제4권1호
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• pp.39-48
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• 2004

Generally, a structural system with large inextensional deformations, or in other words, non-strained deformation is called as 'Unstable Structure', Truss-linked structures, cable structures, membrane structures and movable structures as foldable space structures etc, are included in this category. In this paper, a dynamic analysis method for unstable structural systems is presented. Governing equations for dynamic analysis of unstable truss structures with inextensional displacements are derived. Because of singularity of inverse matrixin in practical analysis of unstable structure, the generalized inverse matrix is Introduced to resolve the singular problem. Also, the RREF technique is used to get the inextensional displacement mode. Two unstable truss structures are analyzed by using presented method. Damping is not considered. From the given results, it is known that proposed method is useful to figure out the dynamic behavior of unstable truss structures.

• Journal of Power Electronics
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• 제18권6호
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• pp.1866-1878
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• 2018

This paper presents a neutral point deviation and ripple compensation control method for application to 3-level NPC converters. The neutral point deviation and its harmonic components are analyzed with a focus on the average current flowing through the neutral point of the dc-link. This paper also proposes a control scheme to compensate for the neutral point deviation and dominant harmonic components under generalized unbalanced grid operating conditions. The positive and negative sequence components of the pole voltages and ac input currents are employed to accurately explain the behavior of 3-level NPC converters. Simulation and experimental results are presented to verify the validity of the proposed method.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 추계종합학술대회 논문집
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• pp.1009-1012
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• 1998

An efficient algorithm for clock skew optimization is proposed in this paper. It construct a new clock routing topology which is the generalized graph model while previous methods uses tree-structured routing topology. Edge-insertion technique is used in order to reduce the clock skew. A link-edge is inserted repeatedly between two sinks whose delay difference is large and the distance is small. As a result, the delay of a sink which has the longer delay is decreased and the clock skew is reduced. The proposed algorithm is implemented in C programming language. From the experimental results, we can get the total wire length minimization under the given skew bound.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 추계학술대회 논문집
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• pp.233-238
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• 2001

In the design and operation of robot arms with flexible links, the equations of motion are required to exactly model the interaction between rigid motion and elastic motion and to be formulated efficiently. Thus, the flexible link is represented on the basis of the D-H rigid link represented to measure the elastic deformation. The equations of motion of robot arms, which are configured by the generalized coordinates of elastic and rigid degrees of freedom, are formulated by using F.E.M to model complex shaped links systematically and by eleminating elastic mode of higher order that does not largely affect option to reduce the number of elastic degree of freedom. Finally presented is the result of simulation to flexible robotic arm whose joints are controlled by direct or PD control.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.533-538
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• 1991

In the design and operation of robot arms with flexible links, the equations of motion are required to exactly model the interaction between rigid motion and elastic motion and to be formulated efficiently. Thus, the flexible link is represented on the basis of the D-H rigid link representation to measure the elastic deformation. The equations of motion of robot arms, which are configured by the generalized coordinates of elastic and rigid degrees of freedom, are formulated by using F.E.M. to model complex shaped links systematically and by eliminating elastic mode of higher order that does not largely affect motion to reduce the number of elastic degree of freedom. Finally, presented is the result of simulation to flexible robotic arm whose joints are controlled by direct or PD control,