• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 D
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• pp.2516-2518
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• 2004

This paper proposes a stability condition in discrete-time affine Takagi-Sugeno (T-S) fuzzy systems with parametric uncertainties and then, introduces the design method of a fuzzy-model-based controller which guarantees the stability. The analysis is based on Lyapunov functions that are continuous and piecewise quadratic. The search for a piecewise quadratic Lyapunov function can be represented in terms of linear matrix inequalities (LMIs).

• Transactions on Control, Automation and Systems Engineering
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• 제1권1호
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• pp.44-49
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• 1999

This paper presents a new T-S(Tae-Sugeno) fuzzy controller design method satisfying the output energy bound. Maximum output energy via a quadratic Lyapunov function to obtain the bound on output energy is derived. LMI(Linear Matrix Inequality) problems which satisfy an output energy bound for both of the continuous-time and discrete-time T-S fuzzy control system are also derived. Solving these LMIs simultaneously, we find a common symmetric positive definite matrix P which guarantees the global asymptotic stability of the system and stable feedback gains K's satisfying the output energy bound. A simple example demonstrates validity of the proposed design method.

• 제어로봇시스템학회논문지
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• 제12권6호
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• pp.547-553
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• 2006

This paper studies digital control of biodynamic model of HIV-1 via intelligent digital redesign (IDR). The purpose of the IDR is to develop an equivalent digital fuzzy controller maintaining the satisfactory performance of an existing continuous-time fuzzy controller in the sense of the state-matching. Some conditions for the stability as well as the global state-matching are provided.. They are given by the form of the linear matrix inequalities (LMIs) and thereby easily tractable by the convex optimization techniques. The main features of the proposed method are that 1) the generalized control scheme is provided for the multirate as well as the single-rate digital controllers; 2) a new compensated block-pulse function method is applied to closely match the states of the continuous-time and the sampled-data fuzzy systems in the discrete-time domain; 3) the two-step procedure of IDR is presented to prevent the performance degradation caused by the additional stability conditions. The applicability of the proposed approach is shown through the biodynamic model of HIV-1.

• 한국지능시스템학회논문지
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• 제3권3호
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• pp.19-26
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• 1993

In this paper, we introduce the notion of H-fuzzy esmitopogenous spaces. In section 1, we give the preliminary definitions and some basic results. In section 2, we show that category HFS of H-fuzzy semitiopogenous spaces and continuous maps between them is topological and cotopological. Using ordinary operations, we characterize coreflective subcatgories and then show that each of Top, Prox, Qunif, and Unig is isomorphic with some coreflective subcategory of HFS. Moreover, we show that sa-HFS is closed under the formation of initial sources in a-HFS, whewe a is a symmetrical elementary operation.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2003년도 춘계 학술대회 학술발표 논문집
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• pp.321-324
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• 2003

본 논문은 임의로 변화하는 입력지연을 갖는 불확실 T-S 퍼지 시스템의 강인 안정화를 논의한다. 임의로 변화하는 입력지연은 유한개의 상태를 갖는 마코프 확률과정으로 표현된다. 디지털 안정화기를 설계하기 위하여 연속시간 T-S 퍼지 시스템을 이산화하며 제어기의 입출력단에 영차의 샘플/홀드 함수를 가정한다. 이산화된 시스템은 확률적 과정에 따라 변화하는 도약 시스템으로 표현된다. 확률적 강인 안정가능성 조건은 선형 행렬 부등식의 현태로 표현된다.

• 충청수학회지
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• 제13권1호
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• pp.71-78
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• 2000

The main goal of this paper is to prove the following theorem ; Let (X, ${\rho}_1$) be a fuzzy normed linear space over K and (Y, ${\rho}_2$) be a fuzzy Banach space over K. If ${\chi}_{B_{{\parallel}{\cdot}{\parallel}}}{\supseteq}{\rho}*$, then (CF(X,Y), ${\rho}*$) is a fuzzy Banach space, where ${\rho}*(f)={\vee}{\lbrace}{\theta}{\wedge}\frac{1}{t({\theta},f)}\;{\mid}\;{\theta}{\in}(0,1){\rbrace}$, $f{\in}CF(X,Y)$, $B_{{\parallel}{\cdot}{\parallel}}$ is the closed unit ball on (CF(X, Y), ${\parallel}{\cdot}{\parallel}$ and ${\parallel}f{\parallel}={\vee}{\lbrace}P^2_{{\alpha}^-}(f(x))\;{\mid}\;P^1_{{\alpha}^-}(x)=1,\;x{\in}X{\rbrace}$, $f{\in}CF(X,Y)$, ${\alpha}{\in}(0,1)$.

• Journal of applied mathematics & informatics
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• 제33권5_6호
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• pp.607-625
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• 2015

Recently, Wang et al. [Computers and Mathematics with Ap-plications 57 (2009) 1232-1248.] and Wang and Watada [Information Sci-ences 179 (2009) 4057-4069.] studied the renewal process and renewal reward process with fuzzy random inter-arrival times and rewards under the T-independence associated with any continuous Archimedean t-norm. But, their main results do not cover the classical theory of the random elementary renewal theorem and random renewal reward theorem when fuzzy random variables degenerate to random variables, and some given assumptions relate to the membership function of the fuzzy variable and the Archimedean t-norm of the results are restrictive. This paper improves the results of Wang and Watada and Wang et al. from a mathematical per-spective. We release some assumptions of the results of Wang and Watada and Wang et al. and completely generalize the classical stochastic renewal theorem and renewal rewards theorem.

• 한국지능시스템학회논문지
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• 제13권3호
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• pp.293-299
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• 2003

본 논문은 인터넷 상에서 임의로 변화하는 입력지연을 갖는 불확실 퍼지 시스템의 지능형 강인 퍼지 제어기 설계를 논의한다. 임의로 변화하는 입력지연은 유한개의 상태를 갖는 마코프 확률과정으로 표현된다. 디지털 안정화기를 설계하기 위하여 연속시간 Takagi-Sugeno 퍼지 시스템을 이산화하며 제어기의 입출력단에 영차의 샘플/홀드 함수를 가정한다.이산화된 시스템은 확률적 과정에 따라 변화하는 도약 시스템으로 표현된다. 확률적 강인 안정가능성 조건은 선형 행렬 부등식의 형태로 표현된다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.40.5-40
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• 2001

In this paper, a new on-line parameter estimation methodology for the general continuous time Takagi-Sugeno(T-S) fuzzy model whose parameters are poorly known or uncertain is presented. An estimator with an appropriate adaptive law for updating the parameters is designed and analyzed based on the Lyapunov theory. The adaptive law is designed so that the estimation model follows the plant parameterized model. By the proposed estimator, the parameters of the T-S fuzzy model can be estimated by observing the behavior of the system and it can be a basis for the indirect adaptive fuzzy control.

• 전자공학회논문지S
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• 제35S권11호
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• pp.53-67
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• 1998

본 논문은 TSK퍼지모델로부터 폐루프의 안정성을 보장하며 그 응답을 자유로이 지정할 수 있는 퍼지제어기와 그 제어기의 설계 방법을 제안한다. 본 논문에서는 퍼지규칙의 선형식이 상수항이 포함되는 affine 방정식으로 된 일반적인 형태의 TSK퍼지모델을 다룬다. 본 논문에서는 제안되는 TSK퍼지제어기는, 선형시스템에서 사용되는 극배치(pole placement)법을 사용하여 설계될 수 있으며, 폐루프의 응답이 원하는 안정된 선형시스템의 거동과 동일하게 되도록 하며, 제어 목표를 바꿀 수 있도록 하며, 적분제어도 가능하게 한다. 시뮬레이션을 통해 퍼지제어기가 유효함을 보인다. 본 논문에서는 연속시스템과 이산시스템 모두에 대해 설명한다.