• Journal of Power System Engineering
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• v.19 no.6
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• pp.60-67
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• 2015

While designing and operating machines, it is very important to understand the dynamic characteristic of the machines. Authors developed the Sylvester-transfer stiffness coefficient method in order to analyze effectively the free vibration of machines or structures. The Sylvester-transfer stiffness coefficient method was derived from the combination of the Sylvester's inertia theorem and the transfer stiffness coefficient method. In this paper, the authors formulate the computational algorithm for flexural free vibration analysis of axisymmetric annular plate using the Sylvester-transfer stiffness coefficient method. To confirm the usefulness of the Sylvester-transfer stiffness coefficient method, the natural frequencies and modes for two computational models computed using the Sylvester-transfer stiffness coefficient method are compared with those computed using the exact solution and the finite element method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.3A
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• pp.412-416
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• 2000

Hadamard matrices are known to be important in designing of the orthogonal codes. in this paper we propose generalized Sylvester construction for Hadamard matrices. We prove it and give an example for the case of Hadamard matrices of order16.

• Korean Journal of Mathematics
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• v.27 no.2
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• pp.515-523
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• 2019

The aim of this paper is to present some necessary and sufficient conditions for existence of solution of Sylvester operator equation involving bounded subnormal operators in a Hilbert space. Our results improve and generalize some results in the literature involving normal operators.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.7
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• pp.577-582
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• 2013

In this paper Legendre wavelets are used to approximate the solutions of linear time-invariant system. The Legendre wavelet and its integral operational matrix are presented and an efficient algorithm to solve the Sylvester matrix equation is proposed. The algorithm is based on the decomposition of the Sylvester matrix equation and the preorder traversal algorithm. Using the special structure of the Legendre wavelet's integral operational matrix, the full order Sylvester matrix equation can be solved in terms of the solutions of pure algebraic matrix equations, which reduce the computation time remarkably. Finally a numerical example is illustrated to demonstrate the validity of the proposed algorithm.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.7
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• pp.777-786
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• 1999

This work is concerned with the assignment of the desired eigenstructure for linear time-varying systems such as missiles, rockets, fighters, etc. Despite its well-known limitations, gain scheduling control appeared to be the focus of the research efforts. Scheduling of frozen-time, frozen-state controller for fast time-varying dynamics is known to be mathematically fallacious, and practically hazardous. Therefore, recent research efforts are being directed towards applying time-varying controllers. In this paper, ⅰ) we introduce a differential algebraic eigenvalue theory for linear time-varying systems, and ⅱ) we also propose an eigenstructure assignment scheme for linear time-varying systems via the differential Sylvester equation based upon the newly developed notions. The whole design procedure of the proposed eigenstructure assignment scheme is very systematic, and the scheme could be used to determine the stability of linear time-varying systems easily as well as provides a new horizon of designing controllers for the linear time-varying systems. The presented method is illustrated by a numerical example.

• Journal of Power System Engineering
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• v.17 no.2
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• pp.46-55
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• 2013

In this paper, the computational algorithm for free vibration analysis of an axisymmetric cylindrical shell is formulated by the Sylvester-transfer stiffness coefficient method (S-TSCM) which combines the Sylvester's inertia theorem and the transfer stiffness coefficient method. After the computational programs for obtaining the natural frequencies and natural modes of the axisymmetric cylindrical shell are made by the S-TSCM and the finite element method (FEM), the computational results which are natural frequencies, natural modes, and computational times by both methods are compared. From the computational results, we can confirm that S-TSCM has the reliability in the free vibration analysis of the axisymmetric cylindrical shell and is superior to FEM in the viewpoint of computational times.

• Bulletin of the Korean Mathematical Society
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• v.38 no.1
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• pp.29-53
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• 2001

This note presents a an indirect adaptive control scheme for first-order continuous-time systems. The estimated plant model is controllable and then the adaptive scheme is free from singularities. The singularities are avoided through a modification of the estimated plant parameter vector so that its associated Sylvester matrix is guaranteed to be nonsingular. That properties is achieved by ensuring that the absolute value of its determinant does not lie below a positive threshold. A modification scheme based on the achievement of a modified diagonally dominant Sylvester matrix of the parameter estimates is also given as an alternative method. This diagonal dominance is achieved through estimates modification as a way to guarantee the controllability of the modified estimated model when a controllability measure of the ‘a priori’ estimated model fails. In both schemes, the use of a hysteresis switching function for the modification of the estimates is not required to ensure the nonsingularity of the Sylvester matrix of the estimates.

• Journal of applied mathematics & informatics
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• v.9 no.2
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• pp.891-897
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• 2002

A symmetric minimal complement at infinity for a given symmetric Silvester data set in the complex plane is contructed.

• Journal for History of Mathematics
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• v.19 no.2
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• pp.77-88
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• 2006

In 1876, America's first Jewish math professor J. J. Sylvester took a department head position at the first research university in USA at the age of 61. He launched the America's first research journal of mathematics in 1877. We study the role and meaning of J. J. Sylvester, F. Klein and E. H. Moore in late 19th century of American mathematics from Korean's perspective.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.21 no.6
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• pp.71-82
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• 2018

This study was conducted to provide ecological basic data that use to establish environmental conditions for cultivation of wild vegetables in 2016-2018. Therefore, we investigated the vegetation structure and the correlation between the community structure and the environmental factors for natural habitats of wild vegetables(Aster glehni, Allium ochotense, and Aruncus sylvester) distributed in Ulleungdo. As a result of population and gradient analysis, the vegetation was classified into Aster glehni community, Allium ochotense community, and Aruncus sylvester community. We confirmed that the classification by population analysis was consistent with that by TWINSPAN method, suggesting that they were complemented each other. The importance value of Aster glehni was the highest in all communities, followed by Aruncus sylvester, Allium ochotense, Hydrangea petiolaris, Dryopteris crassirhizoma, Asperula ldorata, Phryma leptostachya var. asiatica, Disporum viridrescens, Hedera rhombea, Anthriscus sylvestris, and Hepatica maxima. According to the results of DCCA ordination analysis, among those communities, the Aster glehni community was distributed in soil where the nutrition including T-N and O.M. were intermediate. The Allium ochotense community was distributed on the a little high northern slope at the highest altitude where the CEC and O.M. were the highest, and other nutrition and pH were low. The Aruncus sylvester was distributed on high slope and altitude on which the amount of exchangeable cation such as $Ca^{{+}{+}}$, $Mg^{{+}{+}}$ and pH were high, and the CEC, $P_2O_5$, and O.M. were the lowest.