• East Asian mathematical journal
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• 제21권1호
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• pp.41-48
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• 2005

In this paper we first introduce a space of homogeneous type X, and then consider a kind of generalized upper half-space $X{\times}(0,\;\infty)$. We are mainly considered with inequalities for the $L^p$ norms of area functions associated with approach regions in $X{\times}(0,\;\infty)$.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.248-251
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• 1991

A robust monitor AGC(Automatic Gauge Control) system for a hot strip mill plant of POSCO Is designed by minimizing the H.inf. norm of a so called mixed sensitivity function. In order to solve the mininizatlon problem, a polynomial approach proposed by Kwakernaak[5] is used. The controller performance is tested by a computer simulation under various circumstances.

• 제어로봇시스템학회논문지
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• 제4권5호
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• pp.600-607
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• 1998

일반적인 비선형 동역학 최적화문제를 비선형 프로그래밍 문제로 변환하는데 제어변수들을 방사성 기본 함수로 근사화하는 방법이 사용되었다. 방사성 기본 함수의 계수들을 연속적으로 보정하기 위하여 최소수정기법에 기초를 둔 비선형 프로그래밍 알고리즘이 연구되었다. 이러한 알고리즘을 실제적인 다변수 제어 시스템에 적용하여 성능을 검증하였다.

• Journal of the Korean Data and Information Science Society
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• 제16권4호
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• pp.1141-1145
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• 2005

In this note, we show that Theorem 2.1[Kybernetika, 28(1992) 45-49], a result of a functional relationship between the membership function of LR fuzzy numbers of T-sum and T-product, remains valid for convex additive generator and concave shape functions L and R with simple proof. We also consider the case for 0-symmetric R fuzzy numbers.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 심포지엄 논문집 정보 및 제어부문
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• pp.246-248
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• 2006

This paper is concerned with non-fragile guaranteed cost state feedback controller design algorithm for descriptor systems with time-varying delay and static state feedback controller with multiplicative uncertainty. The considered uncertainties are norm-bounded and time delay is time-varying. Under the condition of controller gain variations, conditions for the existence of controller satisfying asymptotic stability and non-fragility and controller design method are derived via LMI approach. Moreover, the measure of non-fragility and the upper bound to minimize guaranteed cost function are given.

• Korean Journal of Mathematics
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• 제13권2호
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• pp.161-176
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• 2005

We consider a model of population dynamics whose mortality function is unbounded. We note that the regularity of the solution depends on the growth rate of the mortality near the maximum age. We propose Gauss-Legendre methods along the characteristics to approximate the solution when the solution is smooth enough. It is proven that the scheme is convergent at fourth-order rate in the maximum norm. We also propose discontinuous Galerkin finite element methods to approximate the solution which is not smooth enough. The stability of the method is discussed. Several numerical examples are presented.

• Journal of the Optical Society of Korea
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• 제8권3호
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• pp.99-103
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• 2004

This paper describes the optimal design of an AWG spectrum to meet various specifications and improve some physical parameters. The objective function is the norm of the difference between design parameters and target values. To obtain the design parameters, the Fourier model is employed and the design variables arc spacing of array waveguide, width of array waveguide, optical path difference, and focal length. The (1+1) Evolution Strategy is employed as the optimization tool. The optimization procedure is applied to a 16-channel AWG and the optimized design variables will considerably improve the system performance.

• Journal of information and communication convergence engineering
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• 제2권3호
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• pp.193-197
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• 2004

In this paper, a combination problem of controllers which are the same type of $H_{\infty}$ controllers designed with different weighting functions. This approach can remove the difficulty in the selection of the weighting functions. As a sub-controller, the Youla type of $H_{\infty}$ controller is used. In the $H_{\infty}$ controller, Youla parameterization is used to minimize $H_{\infty}$ norm of mixed sensitivity function by using polynomial approach. Computer simulation results show the robustness improvement and the performance improvement.

• 대한수학회논문집
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• 제27권2호
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• pp.265-277
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• 2012

In this paper we establish two common fixed point theorems in fuzzy metric spaces. These theorems are generalisations of the Banach contraction mapping principle and the Kannan's fixed point theorem respectively in fuzzy metric spaces. Our result is also supported by examples.

• 대한수학회지
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• 제46권5호
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• pp.967-977
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• 2009

There are three standard weight functions on a linear code viz. Hamming weight, Lee weight, and Euclidean weight. Euclidean weight function is useful in connection with the lattice constructions [2] where the minimum norm of vectors in the lattice is related to the minimum Euclidean weight of the code. In this paper, we obtain an upper bound over the number of parity check digits for Euclidean weight codes detecting and correcting burst errors.