• 전력전자학회논문지
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• 제21권2호
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• pp.126-133
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• 2016

This paper proposes a new PWM method to reduce the common mode voltage change in three-level Vienna rectifier. This new proposed PWM method uses medium voltage vector for the three-level Vienna rectifier to determine the sum of three-phase voltage zero, and the common mode voltage variation is decreased. Using the carrier comparison method, the switching function generator for three-level Vienna rectifier has been proposed. The effects of the proposed PWM method have been verified through simulation using the PSIM.

• 통합자연과학논문집
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• 제5권3호
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• pp.186-189
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• 2012

For the mean vector of a p-variate normal distribution ($p{\geq}3$), the optimal estimation within the class of James-Stein type decision rules under the quadratic loss are given when the underlying distribution is that of a variance mixture of normals and when the norm ${\parallel}\underline{{\theta}}{\parallel}$ in known. It also demonstrated that the optimal estimation within the class of Lindley type decision rules under the same loss when the underlying distribution is the previous type and the norm ${\parallel}{\theta}-\overline{\theta}\underline{1}{\parallel}$ with $\overline{\theta}=\frac{1}{p}\sum\limits_{i=1}^{n}{\theta}_i$ and $\underline{1}=(1,{\cdots},1)^{\prime}$ is known.

• 대한수학회지
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• 제59권5호
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• pp.963-986
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• 2022

Given a dimension function 𝜔, we introduce the notion of an 𝜔-vector weighted digraph and an 𝜔-equivalence between them. Then we establish a bijection between the weakly (ℤ/2)ⁿ-equivariant homeomorphism classes of small covers over a product of simplices ∆^𝜔(1) × ⋯ × ∆^𝜔(m) and the set of 𝜔-equivalence classes of 𝜔-vector weighted digraphs with m-labeled vertices, where n is the sum of the dimensions of the simplicies. Using this bijection, we obtain a formula for the number of weakly (ℤ/2)ⁿ-equivariant homeomorphism classes of small covers over a product of three simplices.

• 전자공학회논문지CI
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• 제45권2호
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• pp.1-9
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• 2008

휴대폰에서 보안 필요성이 증가함에 따라 개인 인증을 위하여 홍채, 지문, 얼굴과 같은 단일 생체 정보를 이용한 많은 연구들이 진행되었으나 단일 생체 인식에서는 인식 정확도에 한계가 있었다. 따라서 본 논문에서는 휴대폰 환경에서 고 인식율을 위해 얼굴과 홍채를 결합하는 방법에 대해 제안한다. 본 논문에서는 근적외선 조명과 근적외선 통과 필터를 부착한 휴대폰의 메가 픽셀 카메라를 사용하여 근적외선 얼굴 및 홍채 영상을 동시에 취득한 후, SVM(Support Vector Machine)을 기반으로 스코어 레벨에서 결합하였다. 또한, 저 연산의 로가리듬(Logarithm) 알고리즘을 사용한 얼굴 데이터의 조명 변화에 대한 정규화와 극 좌표계 변환 및 홍채 코드의 비트 이동 매칭에 의한 홍채 영역의 이동, 회전, 확대 및 축소에 대한 정규화를 통해 SVM의 분류 복잡도와 얼굴, 홍채 데이터의 본인 변화도를 최소화함으로써 인식 정확도를 향상시켰으며, 저 연산의 휴대폰 환경에서 정수혈 기반의 얼굴 및 홍채 인식 알고리즘을 사용하여 처리시간을 향상시켰다. 실험 결과, SVM을 사용한 인식의 정확성이 단일 생체(얼굴 또는 홍채), SUM, MAX, MIN 그리고 Weighted SUM을 사용하는 것보다 우수한 것을 알 수 있었다.

• 대한수학회보
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• 제35권2호
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• pp.269-278
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• 1998

Let ($G,\;{\upsilon}$) be a bounded smooth domain and reflection vector field on $\partial$G, which points uniformly into G. Under the condition that locally for some coordinate system, ${\mid}{\upsilon^i}{\mid}\;i\;=\;1,{\cdot},{\cdot}$,d - 1, where is constant depending on the Lipschitz constant of G, we have tightness for reflected diffusion with jump on G with reflection $\upsilon$ depending only on c. From this, we obtain some properties of L-harmonic function where L is a sum of Laplacian and integro one.

• Korean Journal of Mathematics
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• 제7권1호
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• pp.45-51
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• 1999

Let X and Y be topological vector spaces. For a sequence {$T_j$} of bounded operators from X into Y the $c_0$-multiplier convergence of ${\sum}T_j$ is an invariant on topologies which are stronger (need not strictly) than the topology of pointwise convergence on X but are weaker (need not strictly) than the topology of uniform convergence on bounded subsets of X.

• 호남수학학술지
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• 제2권1호
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• pp.37-44
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• 1980

우리는 먼저 Principal G-bundle와 성질을 살피고 representation of G over C를 irreducible CG-space의 direct sum으로 표시하여 Schur's Lemma를 이용하면 E가 임의의 CG-space, ${\sigma}E=Hom_c(E{\sigma},E)$라 할 때 ${\oplus}_{\sigma}(E_{\sigma}{\otimes}{\sigma}E){\rightarrow}E$ 가 G-ismorphism이 됨을 알아본다. 본 논문의 목적은 이러한 결과를 이용하여 K(X)와 $K_G(X)$의 관계를 구명하는데 있다.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1998년도 학술대회
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• pp.71-75
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• 1998

압축된 비디오 신호를 전송함에 있어 에러에 의해 영상이 손상되는 영향을 최소화하기 위하여 여러 가지 오류은닉 기법들이 제안되고 있다. 본 논문에서는 인터 프레임에서 오류가 발생하여 정보가 손실되었을 경우, 움직임벡터의 효율적인 복구를 통한 오류은닉 방식을 제안하였다. 이를 위해 기존의 블록오류은닉 방식이 갖고 있는 문제점들을 살펴보고 이 중 전체 합 문제(total sum problem)에 대해 해결책으로 제시 될 수 있는 Infinite Norm을 이용한 블록경계정합방식을 제안하였고 실험에 의해 그 성능을 검증하였다.

• 전자공학회논문지B
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• 제29B권11호
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• pp.102-110
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• 1992

In this paper, a new method of character recognition is proposed. It uses density information, in addition to positional and directional information generally used, to recognize a character. Four directional feature primitives are extracted from the thinning templates on the observation that the output of the templates have directional property in general. A simple and fast feature extraction scheme is possible. Features are organized from recursive nonary tree(N-tree) that corresponds to normalized character area. Each node of the N-tree has four directional features that are sum of the features of it's nine sub-nodes. Every feature primitive from the templates are added to the corresponding leaf and then summed to the upper nodes successively. Recognition can be accomplished by using appropriate feature level of N-tree. Also, effectiveness of each node's feature vector was tested by experiment. A method to implement the proposed feature vector organization algorithm into hardware is proposed as well. The third generation node, which is 4$\times$4, is used as a unit processing element to extract features, and it was implemented in hardware. As a result, we could observe that it is possible to extract feature vector for real-time processing.

• ETRI Journal
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• 제36권1호
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• pp.62-68
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• 2014

This paper presents a novel user selection method based on the signal-to-interference-plus-noise ratio (SINR), which is approximated using limited feedback data at the base stations (BSs) of multiple user multiple-input multiple-output (MU-MIMO) systems. In the proposed system, the codebook vector index, the quantization error obtained from the correlation between the measured channel and the codebook vector, and the measured value of the largest singular value are fed back from each user to the BS. The proposed method not only generates precoding vectors that are orthogonal to the precoding vectors of the previously selected users and are highly correlated with the codebook vector of each user but also adopts the quantization error in approximating the SINR, which eventually provides a significantly more accurate SINR than the conventional SINR-based user selection techniques. Computer simulations show that the proposed method enhances the sum rate of the conventional SINR-based methods by at least 2.4 (2.62) bps/Hz when the number of transmit antennas and number of receive antennas per user terminal is 4 and 1(2), respectively, with 100 candidate users and an SNR of 30 dB.