• 대한전기학회논문지
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• 제37권7호
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• pp.484-489
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• 1988

Sufficient conditions concerning the perturbation region of system parameters, which guarantee the asymptotic stability of linear time- varying systems, are presented. These conditions are obtained by Lyapunov function approach for continuous-time and discrete-time systems. Also, a computational algorithm using nonlinear programming is proposed for finding the maximum perturbation region which satisfies the sufficient condition for the continuous-time systems. The technique of finding the solution for the continuous-time systems can also be applied to the discrete-time systems. In the continuous-time case, it is shown by an example that the method proposed in this paper yields much larger perturbation region of parameters than other previously reported results. An example of the perturbation region of system paramters for the discrete-time system is also given.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1998년도 제13차 학술회의논문집
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• pp.244-249
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• 1998

In this paper, the hybrid state space self-tuning control technique Is studied within the framework of fuzzy systems and dual-rate sampling control theory. We show that fuzzy modeling techniques can be used to formulate chaotic dynamical systems. Then, we develop the hybrid state space self-tuning fuzzy control techniques with dual-rate sampling for digital control of chaotic systems. An equivalent fast-rate discrete-time state-space model of the continuous-time system is constructed by using fuzzy inference systems. To obtain the continuous-time optimal state feedback gains, the constructed discrete-time fuzzy system is converted into a continuous-time system. The developed optimal continuous-time control law is then convened into an equivalent slow-rate digital control law using the proposed digital redesign method. The proposed technique enables us to systematically and effective]y carry out framework for modeling and control of chaotic systems. The proposed method has been successfully applied for controlling the chaotic trajectories of Chua's circuit.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 Proceedings of the Korea Automatic Control Conference, 11th (KACC); Pohang, Korea; 24-26 Oct. 1996
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• pp.157-160
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• 1996

Physical systems axe generally continuous-time in nature. However as the data measured from these systems is generally in the form of discrete samples, and most modern signal processing is performed in the discrete-time domain, discrete-time models are employed. This paper describes methods for estimating the coefficients of continuous-time system within a closed loop control system. The method employs a recursive estimation algorithm to identify the coefficients of a discrete-time bilinear-operator model. The coefficients of the discrete-time bilinear-operator model closely approximate those of the corresponding continuous-time Laplace transform transfer function.

• 시스템엔지니어링학술지
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• 제12권1호
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• pp.113-120
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• 2016

Steel in a continuous reheat furnace is heated to higher temperature to be treated in the rolling steel process. Due to this reason the continuous reheat furnace system requires an optimal control system to adjust the temperature inside the furnace. Level 2 control systems for continuous reheat furnaces generate automatic heating set points for the level 1 system of the furnace based on the mathematical thermal model which can give a good estimation of steel heating inside the furnace and is used to adjust heating requirements to optimize furnace combustion. For the current study the analytic methodology based on the design procedure from the systems engineering to develop new level 2 control system of a continuous reheat furnace was proposed. The system analysis and the requirements of the level 2 control system were derived using the unified modeling language (UML) 2.0, and the design of database and the graphic user interface (GUI) for the level 2 control system were conducted.

• East Asian mathematical journal
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• 제35권1호
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• pp.91-98
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• 2019

This paper is concerned with the global existence of strong solution for the controlled ode-pde systems. Also, we consider the continuous dependence of solution on the control.

• Asia pacific journal of information systems
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• 제32권1호
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• pp.125-150
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• 2022

Technology companies launched their intelligent personal assistants (IPAs). IPAs not only provide individuals with a convenient way to interact with technology but also offer them the opportunity to interact with AI in a useful and meaningful form. Therefore, the global IPAs have experienced tremendous growth over the past decade. But maintaining continuous usage intention is still a massive challenge for developers and marketers and previous technology adoption models are not enough to explain continuous usage intention of IPAs. Thus, we adopted the bi-dimensional perspectives of utilitarian and hedonic value in this research model, and investigated how three characteristics of IPAs - anthropomorphism, autonomy, and intelligence - affect utilitarian value and hedonic value, which in turn continuous usage intentions. 227 data were collected from IPA users. The results showed that IPAs' continuous usage intention is significantly determined by both utilitarian and hedonic value, with the hedonic value being more prominent. In addition, the results showed that anthropomorphism and intelligence are the most important antecedents of utilitarian and hedonistic value. The results also illustrated that autonomy is a crucial predictor of utilitarian value rather than hedonistic value. Our work contributes to current research by widening the theoretical understanding of the effect of IPA characteristics on continuous usage intention through bi-dimensional values. Our paper also provides IPAs' developer and marketer guidelines for enhancing continuous usage intention.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제11권1호
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• pp.44-48
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• 2011

The purpose of this paper is to introduce and investigate the concept of fuzzy almost r-minimal continuous function between fuzzy minimal spaces and fuzzy topological spaces. Particularly, we investigate characterizations for the fuzzy almost r-minimal continuity by using generalized fuzzy r-open sets.

• 한국지능시스템학회논문지
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• 제11권2호
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• pp.184-189
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• 2001

First, we find the characterization of fg-closure of a fuzzy set. Second, we study some properties of frg-closeds and fg-continuous mappings. Finaly, we introduce the concept of a fuzzy approximately continuous mapping and study its properties.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제9권3호
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• pp.228-231
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• 2009

In this paper, we introduce the concept of fuzzy $\alpha$-weakly r-continuous mapping on a fuzzy topological space and investigate some properties of such a mapping and the relationships among fuzzy $\alpha$-weakly r-continuity, fuzzy r-continuity and fuzzy weakly r-continuity.

• Transactions on Control, Automation and Systems Engineering
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• 제2권3호
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• pp.163-168
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• 2000

The problems of mixed $H_2/H_{\infty}$ filtering design fer continuous and discrete time linear systems with time delay are investigated. The main purpose is to design a stable mixed $H_2/H_{\infty}$ filter which minimizes the H$_2$Performance measure satisfying a prescribed H$_{\infty}$ norm bound on the closed loop system in continuous-time case and discrete-time case, respectively. The sufficient conditions of existence of filter, the mixed $H_2/H_{\infty}$ filter design method, and the upper bound of performance measure are proposed by LMI(linear matrix inequality) techniques in terms of all finding variables. Also, we present optimization problems in order to get the optimal mixed $H_2/H_{\infty}$ filter in continuous and discrete time case, respectively.