• 제어로봇시스템학회논문지
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• 제19권9호
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• pp.827-833
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• 2013

In this paper, an efficient computational method is presented for state space analysis of bilinear systems via Legendre wavelets. The differential matrix equation is converted to a generalized Sylvester matrix equation by using Legendre wavelets as a basis. First, an explicit expression for the inverse of the integral operational matrix of the Legendre wavelets is presented. Then using it, we propose a preorder traversal algorithm to solve the generalized Sylvester matrix equation, which greatly reduces the computation time. Finally the efficiency of the proposed method is discussed using numerical examples.

• 한국통신학회논문지
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• 제31권4C호
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• pp.434-440
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• 2006

본 논문에서는 단항순열행렬에 의해 구성된 다양한 비실베스터 하다마드 행렬의 고유치가 유도 되었고 이는, 새로 구성한 행렬과 실베스트 하다마드 행렬의 고유치와의 연관성을 보여준다.

• Journal of Communications and Networks
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• 제13권3호
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• pp.211-213
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• 2011

In this paper, we propose a key agreement protocol using Sylvester Hadamard matrices. Users obtain their common key by using a matrix shared in advance. Matrix construction is very simple, and the computation is quite fast. The proposal will be useful for communication between two users, especially for those having low computing power.

• Kyungpook Mathematical Journal
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• 제56권2호
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• pp.529-539
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• 2016

In this paper, we obtain solution for the first order matrix dynamical system and also we provide set of necessary and sufficient conditions for complete controllability and complete observability of the Sylvester matrix dynamical system.

• 동력기계공학회지
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• 제22권6호
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• pp.11-19
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• 2018

In this study, the authors examine the propulsion shafting of the training ship SAEDONGBAEK and perform modeling to analyze the torsional free vibration of the shafting. In this paper, the computational algorithm for analyzing the torsional free vibration of the shafting with a reduction gear is formulated by the sylvester-transfer stiffness coefficient method (S-TSCM) that is a recently developed and a powerful method in free vibration analysis. According to the state of the controllable pitch propeller of the shafting and the temperature of the elastic coupling, the torsional free vibration of the shafting is performed by the S-TSCM. The authors examine the changes of the natural frequencies and natural modes which are the results of the torsional free vibration analysis of the shafting.

• 제어로봇시스템학회논문지
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• 제14권12호
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• pp.1270-1277
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• 2008

A Haar wavelet based numerical method for solving singularly perturbed linear time invariant system is presented in this paper. The reduced pure slow and pure fast subsystems are obtained by decoupling the singularly perturbed system and differential matrix equations are converted into algebraic Sylvester matrix equations via Haar wavelet technique. The operational matrix of integration and its inverse matrix are utilized to reduce the computational time to the solution of algebraic matrix equations. Finally a numerical example is given to demonstrate the validity and applicability of the proposed method.

• 한국수학사학회지
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• 제33권1호
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• pp.21-32
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• 2020

Daniel Coit Gilman, the first president of Johns Hopkins University, aspired to build an ideal university focused on the competent faculty and their research. His plan was carried out through opening the first American graduate program, hiring professors with the highest-level research performances, assigning them less teaching burdens, and encouraging them to actively publish professional journals. He introduced Department of Mathematics as an initial model to put his plan into practice, and James Joseph Sylvester, a British mathematician invited as the first mathematics professor to Johns Hopkins University, made it possible in a short time. Their concerted efforts led to building the Department of Mathematics as a professional research institute for research, higher education, and expert training as well as to publishing American Journal of Mathematics.

• 동력기계공학회지
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• 제20권2호
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• pp.5-16
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• 2016

Generally, methods using transfer techniques, like the transfer matrix method and the transfer stiffness coefficient method, find natural frequencies using the sign change of frequency determinants in searching frequency region. However, these methods may omit some natural frequencies when the initial frequency interval is large. The Sylvester-transfer stiffness coefficient method ("S-TSCM") can always obtain all natural frequencies in the searching frequency region even though the initial frequency interval is large. Because the S-TSCM obtain natural frequencies using the number of natural frequencies existing under a searching frequency. In this paper, the algorithm for the free vibration analysis of axisymmetric conical shells was formulated with S-TSCM. The effectiveness of S-TSCM was verified by comparing numerical results of S-TSCM with those of other methods when analyzing free vibration in two computational models: a truncated conical shell and a complete (not truncated) conical shell.

• 대한기계학회논문집A
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• 제28권11호
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• pp.1621-1628
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• 2004

This paper proposes a design methodology for the robust observer using the eigenstructure assignment in multi-output systems so that the observer is less sensitive to the ill-conditioning factors such as unknown initial estimation error, modeling error and measurement bias in transient and steady-state observer performance. The robustness of the observer can be achieved by selecting the desired eigenvector matrix to have a small condition number that guarantees the small upper bound of the estimation error. So the left singular vectors of the unitary matrix spanned by space of the achievable eigenvectors are selected as a desired eigenvectors. Also, this paper proposes how to select the desired eigenvector based on the measure of observability and designs the observer with small gain. An example of a spindle drive system is simulated to validate the robustness to the ill-conditioning factors in the observer performance.

• 한국수학사학회지
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• 제20권3호
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• pp.127-146
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• 2007

미국수학사에서 가장 중요한 시기로 여겨지는 1890년에서 1950년 사이의 미국수학계의 발전과정을 당시의 미국수학 연구에 있어서 혁신적 발전의 계기를 제공한 시카고 대학의 초대 수학과장 E.H. Moore 의 역할을 중심으로 고찰한다. 19세기말 아직 낙후되었던 미국 수학계는 시카고 대학의 핵심 학과였던 수학과는 총장의 비전을 같이 할 우수교수를 확보하고, 새로운 제도 하에서 선발된 우수 대학원 학생들을 탐구지향 교수법으로 지도하며 미국 수학연구의 초장기에 우수한 인재를 공급하기 시작한다. 이를 통하여 미국은 인재양성과 새로운 연구 분야 및 연구방법의 개척에 성공하고, 1950년 국제수학자대회(ICM)를 미국에서 개최하며, 당당히 세계수학의 주류에 진입한다. 본 원고는 위의 발전과정이 현재 한국에 주는 의미를 분석한다.