• Journal of applied mathematics & informatics
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• 제20권1_2호
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• pp.345-354
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• 2006

In this paper first, we find a canonical symmetrical trapezoidal(triangular) for the solution of the fuzzy linear system $A\tilde{x}=\tilde{b}$, where the elements in A and $\tilde{b}$ are crisp and arbitrary fuzzy numbers, respectively. Then, a model for fuzzy linear programming problem with fuzzy variables (FLPFV), in which, the right hand side of constraints are arbitrary numbers, and coefficients of the objective function and constraint matrix are regarded as crisp numbers, is discussed. A numerical procedure for calculating a canonical symmetrical trapezoidal representation for the solution of fuzzy linear system and the optimal solution of FLPFV, (if there exist) is proposed. Several examples illustrate these ideas.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1593-1598
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• 2004

In this paper, we use the input and output maps and develop simple procedures to obtain realizations for linear continuous-time systems. The procedures developed are numerically efficient and yield explicit formulae for the state space matrices of the realization in terms of the system parameters, notably the system modes. Both cases of the systems with distinct modes and repeated modes are treated. We also present a procedure for converting a realization obtained through the input or output map into the Jordan canonical form. The transformation matrices required to bring the realization into the Jordan canonical form are specified entirely in terms of the system modes.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.601-604
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• 1997

In this paper, a pole assignment problem in the unit disk for a linear discrete system is discussed. The analysis is based on the Luenberger's canonical form and Gershgorin's disk. The proposed method for pole assignment is convenient for a linear time invariant discrete system.

• 대한수학회지
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• 제32권3호
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• pp.447-459
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• 1995

A fundamental problem is to construct linear systems with given transfer functions. This problem has a well known solution for unitary linear systems whose state spaces and coefficient spaces are Hilbert spaces. The solution is due independently to B. Sz.-Nagy and C. Foias [15] and to L. de Branges and J. Ball and N. Cohen [4]. Such a linear system is essentially uniquely determined by its transfer function. The de Branges-Rovnyak construction makes use of the theory of square summable power series with coefficients in a Hilbert space. The construction also applies when the coefficient space is a Krein space [7].

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.760-763
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• 2007

We studied how linear and nonlinear heart rate dynamics differ between normal fetuses and uncomplicated small-forgestational age (SGA) fetuses, aged 32-40 weeks' gestation. We analyzed each fetal heart rate time series for 20 min and quantified the complexity (nonlinear dynamics) of each fetal heart rate (FHR) time series by approximate entropy (ApEn) and correlation dimension (CD). The linear dynamics were analyzed by canonical correlation analysis (CCA). The ApEn and CD of the uncomplicated SGA fetuses were significantly lower than that of the normal fetuses in all three gestational periods (32-34, 35-37, 38-40 weeks). Canonical correlation ensemble in SGA fetuses is slightly higher than normal ones in all three gestational periods, especially at 35-37 weeks. Irregularity and complexity of the heart rate dynamics of SGA fetuses are lower than that of normal ones. Also, canonical ensemble in SGA fetuses is higher than in normal ones, suggesting that the FHR control system has multiple complex interactions. Along with the clear difference between the two groups' non-linear chaotic dynamics in FHR patterns, we clarified the hidden subtle differences in linearity (e.g. canonical ensemble). The decrease in non-linear dynamics may contribute to the increase in linear dynamics. The present statistical methodology can be readily and routinely utilized in Obstetrics and Gynecologic fields.

• Journal of applied mathematics & informatics
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• 제8권2호
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• pp.659-668
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• 2001

Let S(z) be a power series with operator coefficients such that multiplication by S(z) is an everywhere defined transformation in the square summable power series C(z). In this paper we show that there exists a reproducing kernel Krein space which is state space of extended canonical linear system with transfer function S(z). Also we characterize the reproducing kernel function of the state space of a linear system.

• 호남수학학술지
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• 제29권4호
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• pp.511-521
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• 2007

Let S($z_1$, $z_2$) be a power series with operator coefficients such that multiplication by 5($z_1$, $z_2$) is a contractive transformation in the Hilbert space $\mathbf{H}_2$($\mathbb{D}^2$, C). In this paper we show that there exists a Hilbert space D($\mathbb{D}$,$\bar{S}$) which is the state space of extended canonical linear system with a transfer fucntion $\bar{S}$(z).

• 대한전자공학회논문지TC
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• 제47권2호
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• pp.9-17
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• 2010

최근 들어, 차세대 무선 광대역 통신 시스템의 전송 방식으로 큰 관심을 받고 있는 OFDM (Orthogonal Frequency Division Multiplexing) 시스템은 다수 반송파 전송의 특수한 형태로 볼 수 있으며 하나의 데이터열이 보다 낮은 데이터 전송률을 갖는 부반송파를 통해 전송된다. OFDM을 사용하는 중요한 이유 중 하나는 OFDM을 사용하면 주파수 선택적 페이딩이나 협대역 간섭에 대한 강건함이 증가하기 때문이다. 하지만 출력 신호의 크기가 Rayleigh 분포를 갖기 때문에 무선 통신 환경에서 SSPA (Solid State Power Amplifier)와 같은 고출력 증폭기 (High Power Amplifier; HPA)의 비선형 특성으로 인하여 단일 반송파 전송 방식보다 심각한 비선형 왜곡이 발생하게 된다. 본 논문에서는 OFDM 신호의 높은 PAPR (Peak-to-Average Power Ratio)과 HPA의 비선형성에 의한 신호의 왜곡과 스펙트럼의 확산을 방지하기 위해 canonical piecewise-linear (PWL) 모델 기반의 디지털 사전왜곡기를 제안한다. 제안된 사전왜곡기의 성능평가를 위해 AWGN (Additive White Gaussian Noise) 채널 하에서 QPSK, 16-QAM, 64-QAM 변조 방식을 이용하고, 1024-point FFT/IFFT로 구현된 OFDM 시스템에 대한 모의실험을 실시한 결과, 비트오율과 비선형성 개선측면에서 우수한 성능을 나타내었다.

• International Journal of Control, Automation, and Systems
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• 제6권1호
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• pp.142-148
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• 2008

In this paper, we deal with the problem of reducing the order of the detection filter for the linear time-invariant system. Even if the detection filter is generally designed in the form of full order linear observer, we show that it is possible to reduce its order when the response of fault signals is limited to a subspace of the estimation state space. We propose a method to extract the subspace using the observer canonical form considering the dynamics related to the remaining subspace acts as a disturbance. We designed a reduced order detection filter to reject the disturbance as well as to guarantee fault detection and isolation. A simulation result for a 5th order system is presented as an illustrative example of the proposed design method.

• 대한수학회논문집
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• 제12권4호
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• pp.895-904
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• 1997

Let B(z) be a power series with operator coefficients where multiplication by B(z), T, is a contractive and everywhere defined transforamtion in the square summable power series. Then there is a Julia operator U for T such that $$ U = (T D)(\tilde{D}^* L) \in B(H \oplus D, K \oplus \tilde{D}), $$ where D is the state space of a conjugate canonical linear system with transfer function B(z).