• 대한전자공학회논문지
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• 제19권4호
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• pp.15-20
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• 1982

대형 시스템에 있어서 안정도는 매우 중요하며 특히 분산 제어로 안정 가능한 시스템에 관한 연구는 점차 중요성을 더해 가고 있다. 본 논문은 몇 개의 국부 시스템으로 구성된 대형 시스템에서 각 국부 시스템의 제어기가 자기 자신의 입력만을 제어하고 또한 자기 자신의 출력만을 관측하는 경우에 대형 시스템이 안정하기 위한 충분 조건을 제시하였다. 이 충분 조건은 Sezer와 Huseyin이 제시한 조건을 확상시킨 것이며 상호 연관된 시스템을 표현하는 시스템 모델은 가장 일반적이다. 특수한 경우로써 각 부 시스템이 단일 입력이고 가제어 companion형으로 주어졌을 때 본 논문에서 사용한 증명 방법카 유사하게 Ikeda와 Siljak이 제시한 충분 조건을 증명하였다.

• Journal of Ubiquitous Convergence Technology
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• 제2권1호
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• pp.18-26
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• 2008

The invariance relation existing in the non-negative matrix factorization (NMF) is used for constructing robust image hashes in this work. The image is first re-scaled to a fixed size. Low-pass filtering is performed on the luminance component of the re-sized image to produce a normalized matrix. Entries in the normalized matrix are pseudo-randomly re-arranged under the control of a secret key to generate a secondary image. Non-negative matrix factorization is then performed on the secondary image. As the relation between most pairs of adjacent entries in the NMF's coefficient matrix is basically invariant to ordinary image processing, a coarse quantization scheme is devised to compress the extracted features contained in the coefficient matrix. The obtained binary elements are used to form the image hash after being scrambled based on another key. Similarity between hashes is measured by the Hamming distance. Experimental results show that the proposed scheme is robust against perceptually acceptable modifications to the image such as Gaussian filtering, moderate noise contamination, JPEG compression, re-scaling, and watermark embedding. Hashes of different images have very low collision probability. Tampering to local image areas can be detected by comparing the Hamming distance with a predetermined threshold, indicating the usefulness of the technique in digital forensics.

• 한국CDE학회논문집
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• 제14권6호
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• pp.404-414
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• 2009

In the computational molecular analysis, 3D structural comparison for protein searching plays a very important role. As protein databases have been grown rapidly in size, exhaustive search methods cannot provide satisfactory performance. Because exhaustive search methods try to handle the structure of protein by using sphere set which is converted from atoms set, the similarity calculation about two sphere sets is very expensive. Instead, the filter-and-refine paradigm offers an efficient alternative to database search without compromising the accuracy of the answers. In recent, a very fast algorithm based on the inter-atomic distance has been suggested by Ballester and Richard. Since they adopted the moments of distribution with inter-atomic distance between atoms which are rotational invariant, they can eliminate the structure alignment and orientation fix process and perform the searching faster than previous methods. In this paper, we propose a new 3D shape descriptor. It has properties of the general shape distribution and useful property in screening the molecular database. We show some experimental results for the validity of our method.

• Journal of Computational Design and Engineering
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• 제2권2호
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• pp.79-87
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• 2015

Surface segmentation and edge feature lines extraction from fractured fragments of relics are essential steps for computer assisted restoration of fragmented relics. As these fragments were heavily eroded, it is a challenging work to segment surface and extract edge feature lines. This paper presents a novel method to segment surface and extract edge feature lines from triangular meshes of irregular fractured fragments. Firstly, a rough surface segmentation is accomplished by using a clustering algorithm based on the vertex normal vector. Secondly, in order to differentiate between original and fracture faces, a novel integral invariant is introduced to compute the surface roughness. Thirdly, an accurate surface segmentation is implemented by merging faces based on face normal vector and roughness. Finally, edge feature lines are extracted based on the surface segmentation. Some experiments are made and analyzed, and the results show that our method can achieve surface segmentation and edge extraction effectively.

• Kyungpook Mathematical Journal
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• 제56권3호
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• pp.657-668
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• 2016

Given a partition ${\lambda}=({\lambda}_1,{\lambda}_2,{\ldots},{\lambda}_l)$ of a positive integer n, let Tab(${\lambda}$, k) be the set of all tabloids of shape ${\lambda}$ whose weights range over the set of all k-compositions of n and ${\mathcal{OP}}^k_{\lambda}_{rev}$ the set of all ordered partitions into k blocks of the multiset $\{1^{{\lambda}_l}2^{{\lambda}_{l-1}}{\cdots}l^{{\lambda}_1}\}$. In [2], Butler introduced an inversion-like statistic on Tab(${\lambda}$, k) to show that the rank-selected $M{\ddot{o}}bius$ invariant arising from the subgroup lattice of a finite abelian p-group of type ${\lambda}$ has nonnegative coefficients as a polynomial in p. In this paper, we introduce an inversion-like statistic on the set of ordered partitions of a multiset and construct an inversion-preserving bijection between Tab(${\lambda}$, k) and ${\mathcal{OP}}^k_{\hat{\lambda}}$. When k = 2, we also introduce a major-like statistic on Tab(${\lambda}$, 2) and study its connection to the inversion statistic due to Butler.

• Kyungpook Mathematical Journal
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• 제56권3호
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• pp.1017-1045
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• 2016

Using a combination of calculational and theoretical approaches, we establish results that relate two knot invariants, the Alexander polynomial, and the number of quandle colourings using any finite linear Alexander quandle. Given such a quandle, specified by two coprime integers n and m, the number of colourings of a knot diagram is given by counting the solutions of a matrix equation of the form AX = 0 mod n, where A is the m-dependent colouring matrix. We devised an algorithm to reduce A to echelon form, and applied this to the colouring matrices for all prime knots with up to 10 crossings, finding just three distinct reduced types. For two of these types, both upper triangular, we found general formulae for the number of colourings. This enables us to prove that in some cases the number of such quandle colourings cannot distinguish knots with the same Alexander polynomial, whilst in other cases knots with the same Alexander polynomial can be distinguished by colourings with a specific quandle. When two knots have different Alexander polynomials, and their reduced colouring matrices are upper triangular, we find a specific quandle for which we prove that it distinguishes them by colourings.

• 한국양식학회지
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• 제22권1호
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• pp.51-55
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• 2009

Transcriptional response of the second isoform of glyceraldehyde (GAPDH-2) to infectious challenges using various bacterial species and the rockbream iridovirus (RBIV) was examined in the spleen of the barred knifejaw (Oplegnathus fasciatus). Bacterial challenges of the juvenile barred knifejaws with Escherichia coli, Edwardsiella tarda, Vibrio anguillarum and Streptococcus iniae resulted in the significant elevation of the GAPDH-2 transcripts in the spleen up to 12-fold relative to that in the non-challenged controls (PBS-injected). In addition, the barred knifejaw fingerlings injected with RBIV stock also represented the highly upregulated mRNA expression of the GAPDH-2 up to more than 20-fold when compared to that of control fingerings. Results obtained from this study strongly suggest that the GAPDH-2 is no longer a housekeeping glycolytic protein and rather than that it might be associated with immune-relevant cellular activities. From this finding, the traditional dogma for the use of GAPDH as an invariant standard for gene expression assays should be carefully revised depending on the kinds of biological stimulations applied in this species.

• 한국정보처리학회논문지
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• 제3권6호
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• pp.1636-1645
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• 1996

본 논문에서는 패턴을 효과적으로 분류하기 위하여 화상자료의 특성인 이웃 화소 간의 종속성을 잘 표현해 주는 깁스확률장의 크리크를 바탕으로 2차원 조건부 모멘트 를 제안하였다. 이 알고리즘 구축은 공간정보를 갖는 조건부 모멘트를 이용하여 특정 벡터를 추출하는 과정과 패턴을 분류하는 과정으로 분리하여 생각한다. 특정벡터를 추출하는 과정은 하나의 패턴에 대해 깁스분포의 크리크로 표현된 파라미터를 추정한 다음, 2차원 조건부 모멘트들을 계산하여 특정벡터로부터 제안된 판별거리함수를 계 산하여 여러 원형 패턴 가운데 최소거리를 산출한 미지의 패턴을 원형패턴으로 분류 한다. 제안된 방법의 성능을 검증하기 위하여 대문자와 소문자 52자로 된 훈련 데이 타를 만들어 486 PC 66Mhz에서 실험을 한 결과 97.5% 이상의 분류성능이 있음을 밝혔 다.

• Journal of Power Electronics
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• 제16권3호
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• pp.1131-1140
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• 2016

A simple design for a sliding mode observer is proposed for EV lithium battery SOC estimation in this paper. The proposed observer does not have the limiting conditions of existing observers. Compared to the design of previous sliding mode observers, the new observer does not require a solving matrix equation and it does not need many observers for all of the state components. As a result, it is simple in terms of calculations and convenient for engineering applications. The new observer is suitable for both time-variant and time-invariant models of battery SOC estimation, and the robustness of the new observer is proved by Liapunov stability theorem. Battery tests are performed with simulated FUDS cycles. The proposed observer is used for the SOC estimation on both unchanging parameter and changing parameter models. The estimation results show that the new observer is robust and that the estimation precision can be improved base on a more accurate battery model.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제50권9호
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• pp.431-437
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• 2001

Since the eddy current problem usually depends on the geometry of the moving conductive sheet and the shape of the pole projection area, there is no general method to find out its analytical solution. The analysis of the eddy current in a rotating disk is performed in the case of time-invariant field to find its analytical solution. As a method to solve the eddy current problem, the concept of the Coulomb charge and image method are proposed with the consideration of the boundary condition. Firstly, the line charge is obtained from the volume charge generated in the rotating disk and Coulomb's law is applied. Secondly, the finite disk radius is considered by introducing an imaginary eddy current to satisfy the boundary condition that the radial component of the eddy current is zero at the edge of the relating disk. Thirdly, the braking torque is calculated by applying Lorentz force law. Finally, the computed braking torque is compared with the measured one As a result, it can be said that the proposed model presents fairly accurate results in a low angular velocity range although a large error is observed as the angular velocity of the disk increases.