• 대한수학회논문집
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• 제10권4호
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• pp.917-924
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• 1995

Let $P_I$ be the convex compact set of all unital positive linear maps between the $n \times n$ matrix algebra over the complex field. We find a necessary and sufficient condition for which two maximal faces of $\cap P_I$ intersect. In particular, we show that any pair of maximal faces of $P_I$ has the nonempty intersection, whenever $n \geq 3$.

• 대한수학회보
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• 제50권6호
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• pp.2027-2034
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• 2013

In this article, it is proved that under some conditions every bijective Jordan triple product homomorphism from generalized matrix algebras onto rings is additive. As a corollary, we obtain that every bijective Jordan triple product homomorphism from $M_n(\mathcal{A})$ ($\mathcal{A}$ is not necessarily a prime algebra) onto an arbitrary ring $\mathcal{R}^{\prime}$ is additive.

• 대한수학회논문집
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• 제28권1호
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• pp.1-9
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• 2013

We consider the sets of matrix ordered pairs which satisfy extremal properties with respect to Boolean rank inequalities of matrices over nonbinary Boolean algebra. We characterize linear operators that preserve these sets of matrix ordered pairs as the form of $T(X)=PXP^T$ with some permutation matrix P.

• 한국자동차공학회논문집
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• 제2권1호
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• pp.116-127
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• 1994

A method using the linear matrix algebra is developed in order to determine unknown external forces in linear structural analyses. The method defines a matrix which represents the linearity of the vibrational analysis for a structural system. The unknown external forces are determined by the operations of the matrix. The method is applied to find an engine motion in an automobile system. For a simulation process, an exhaust system is modeled and analyzed by the finite element method. The validity of the simulation is verified by comparing with the experimental results the free vibration. Also, an experiment on the forced vibration is performed to determine the damping ratio of the exhaust sysetm. Estimated model parameters(natural frequency, mode shape) are in accord with the experimental results. Because the method merely repeats the transpose and inverse operations of a matrix, the solution is extremely easy and simple. Moreover, it is more accurate than the existing methods in that there is no artificial assumptions in the calculation processes. Therefore, the method is found to be reliable for the analysis of the exhaust system considering the characteristics of vibrations. Although the suggested method is tested by only the exhaust system here, it can be applied to general structures.

• 대한수학회지
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• 제40권6호
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• pp.943-950
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• 2003

The maximal column rank of an m by n matrix A over max algebra is the maximal number of the columns of A which are linearly independent. We compare the maximal column rank with rank of matrices over max algebra. We also characterize the linear operators which preserve the maximal column rank of matrices over max algebra.

• Korean Journal of Mathematics
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• 제21권4호
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• pp.503-521
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• 2013

지난 20여 년간 선형대수학 교수학습과정에서 공학적 도구의 필요성이 지속적으로 제기되어 왔으며 실제 선형대수학 교재를 통하여 관련된 다양한 도구가 소개되었다. 그러나 한국 대학의 선형대수학 교육에서는 다양한 현실적인 이유로 도구 활용이 미진하였다. 따라서 오랜 기간 선형대수학의 이론 교육에만 치중한 경향이 있다. 본 논문에서는 한국의 대학수학교육 부분 중 공학적 도구 도입에서 제기되는 문제점과 어려움을 모두 해결할 수 있는 대안을 구체적으로 제시한다. 그리고 실제 대학수학교육에서 공학적 도구의 활용이 이루어진 모델의 하나로 Sage를 이용하여 개발한 선형대수학 웹 콘텐츠와 행렬계산기를 소개한다. 이를 활용하면 교육현장에서 선형대수학의 대부분의 개념을 언제, 어디서나 사용가능한 무료 도구와 함께 직관적으로 이해하고, 시각화 및 대용량 계산을 수시로 편리하게 수행하며 학습할 수 있다. 더구나 다루는 행렬의 크기를 자연스럽게 변형 및 확대할 수 있다. (http://sage.skku.edu/static/mc.html)

• 대한수학회보
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• 제53권2호
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• pp.541-550
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• 2016

In this paper, we introduce a quasi-Banach algebra of infinite matrices, which is inverse-closed in the Banach algebra B(${\ell}^2$) of all bounded operators on ${\ell}^2$.

• 대한수학회지
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• 제34권4호
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• pp.791-807
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• 1997

There are several kinds of orders in a quaternion algebra. In this article, the relation between the orders is studied.

• Journal of applied mathematics & informatics
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• 제29권5_6호
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• pp.1525-1532
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• 2011

The $m{\times}n$ Boolean matrix A is said to be of Boolean rank r if there exist $m{\times}r$ Boolean matrix B and $r{\times}n$ Boolean matrix C such that A = BC and r is the smallest positive integer that such a factorization exists. We consider the the sets of matrix ordered pairs which satisfy extremal properties with respect to Boolean rank inequalities of matrices over nonbinary Boolean algebra. We characterize linear operators that preserve these sets of matrix ordered pairs as the form of $T(X)=PXP^T$ with some permutation matrix P.

• 대한수학회보
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• 제56권4호
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• pp.939-959
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• 2019

Using generalized graded crossed products, we give necessary and sufficient conditions for a simple algebra over a Henselian valued field (under some hypotheses) to have Kummer subfields. This study generalizes some known works. We also study many properties of generalized graded crossed products and conditions for embedding a graded simple algebra into a matrix algebra of a graded division ring.