• 동력기계공학회지
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• 제19권6호
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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.

• 한국통신학회논문지
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• 제25권3A호
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• pp.412-416
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• 2000

하다마드 행렬은 직교부호를 설계함에 있어서 매우 중요한 행렬이다. 본 논문에서는 하다마드 행렬을 구성하는 실베스터(Sylvester) 방식의 새로운 일반화된 방법을 소개하고 이를 증명한 후, 크기 16에서 예를 들어 설명한다. 이 방법을 사용하면 서로 비동치관계에 있는 다양한 종류의 하다마드 행렬을 쉽게 생성할 수 있다.

• Korean Journal of Mathematics
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• 제27권2호
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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.

• 제어로봇시스템학회논문지
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• 제19권7호
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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.

• 제어로봇시스템학회논문지
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• 제5권7호
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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.

• 동력기계공학회지
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• 제17권2호
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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.

• 대한수학회보
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• 제38권1호
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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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• 제9권2호
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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.

• 한국수학사학회지
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• 제19권2호
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• pp.77-88
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• 2006

미국 버지니아대학 수학과 교수, 보험회사 계리인, 변호사를 거쳐, 영국 육군사관학교 교관으로 55세에 정년을 한 유태계 영국 수학자 J. J. 실베스터는 61세의 나이로 1876년 미국 최초의 연구중심대학인 존스홉킨스대학에 초대 수학과장으로 초빙되어 연구 인력을 배출하고 미국 최초의 수학연구저널을 발간하며 미국에 현대수학의 연구 여건을 마련 해 준다. 본 논문은 그와 그가 후임으로 추천한 F. 클라인이 19세기 후반 미국수학계에 끼친 역할을 분석한다. 우리는 실베스터와 클라인과 미국인 수학자 E. H. 무어가 100여년 전 낙후된 미국 수학을 당시 유럽 중심의 수학계 주류에 진입시키는 과정에서의 역할과 이 과정이 한국에서 갖는 의미를 생각한다.

• 한국환경복원기술학회지
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• 제21권6호
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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.