• Journal of Ubiquitous Convergence Technology
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• v.2 no.2
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• pp.59-66
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• 2008

In this study, Software Defined Radio (SDR) technology-based digital filterbank architecture applicable to a multiple-channel processing system such as a wireless mobile communication system using Code Division Multiple Access (CDMA) technology is proposed. The technique includes a micro-processor to redesign Finite Impulse Response (FIR) filter coefficients according to specific system information and to download the filter coefficients to one digital Band Pass Filter (BPF) to reconfigure another system. The feasibility of the algorithm is verified by computer simulation and by implementing a multiple-channel signal generator that is reconfigurable to other system profiles, including those of a Wideband Code Division Multiple Access (WCDMA) system and a CDMA system.

• Journal of the Korean Institute of Intelligent Systems
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• v.15 no.1
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• pp.36-41
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• 2005

The smart space is composed of the wire and/or wireless network, multi-sensor-based environment, and many various controllers. For the smart space, this paper presents a new design method of multirate digital decentralized controller using the digital redesign technique. In specific, the proposed method is based on the delta-operator and the multirate sampling and takes the form of the LMIs. To shows the feasibility of the suggested method, the computer simulations for HVAC system are provided.

• 제어로봇시스템학회:학술대회논문집
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• 1998.10a
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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.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2002-2004
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• 2001

In this paper, we propose the PAM fuzzy controller using intelligent digital redesign method for nonlinear system. We design the continuous-time controller using TSK fuzzy model of nonlinear system, and then design the intelligent digital PAM controller based on continuous-time controller. Finally, the feasibility and stability of the proposed method has been proven through a computer simulation.

• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2251-2253
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• 2004

본 논문은 선형 행렬 부등식 기반의 디지털 재설계 기법의 점근적 성질을 논의한다. 이를 위하여 델타 작용소를 기반한 디지털 재설계 기법을 제안한다. 샘플링 주기의 감소에 따른 재설계된 디지털 제어기의 성능회복을 증명한다.

• KIEAE Journal
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• v.7 no.2
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• pp.47-55
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• 2007

Development of digital technology has become closely connected with housing environment. Especially for the matured population, it is very important because they need substantial support in their daily lives. Therefore, the purpose of this paper is to identify needs of digital network services for future housing development. Previous researches were limited to digital technology of network systems and its usages. On the other hand, this study focuses on not only the technology but services. This study consists of literatures review and empirical survey. The subjects were the mid-age and pre-elderly between 45 to 65. The analysis of this study results outlined as follows: First, the pre-elderly appeared to have, in general, positive perceptions about digital services of the housing environment. The results of needs for each space's, showed strongly in basic safety and aiding system for memories. Second, there are differences in needs according to respondent's characteristics such as sex, income, job, house type, experience in digital system. Third, there are differences between what they think and what they really responded in both spaces and services. It menas that present planning elements may not attractive and suitable to residents. Therefore it is necessary to redesign the services. In the future, the most important thing is, making comfortable space not convenient space. That is, excluding unnecessary elements and pick up the right ones for resident's real demands.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.1
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• pp.60-65
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• 2008

In this paper, we concern the stability of smart space by using the robust digital controller. The proposed methodologies are based on the intelligent digital redesign (IDR). More precisely, we represent the nonlinear and uncertain analog system as the Takaki-Sugeno (T-S) fuzzy model. Then the IDR problem can be reduced to find the digital gains minimizing the norm distance between the closed-loop states of the analog and digital control. Its constructive conditions are expressed as the linear matrix inequalities (LMIs). At last, a numerical example, HVAC system, is demonstrated to visualize the feasibility of the proposed methodology.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.2
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• pp.138-143
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• 2006

This paper presents intelligent digital redesign method for hybrid state space fuzzy-model-based controllers. For effectiveness and stabilization of continuous-time uncertain nonlinear systems under discrete-time controller, Takagi-Sugeno(TS) fuzzy model is used to represent the complex system. And global approach design problems viewed as a convex optimization problem that we minimize the error of the norm bounds between nonlinearly interpolated linear operators to be matched. Also, by using the bilinear and inverse bilinear approximation method, we analyzed nonlinear system's uncertain parts more precisely. When a sampling period is sufficiently small, the conversion of a continuous-time structured uncertain nonlinear system to an equivalent discrete-time system have proper reason. Sufficiently conditions for the global state-matching of the digitally controlled system are formulated in terms of linear matrix inequalities (LMIs). Finally, a TS fuzzy model for the chaotic Lorentz system is used as an . example to guarantee the stability and effectiveness of the proposed method.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2007.04a
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• pp.409-412
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• 2007

본 논문에서는 근사 이산-시간 모델 기반 지능형 디지털 재설계 기법의 타당성에 대해서 논의한다. 타당성을 검증하기 위해 재설계된 디지털 제어 퍼지 시스템의 안정도 및 상태-정합에 특성이 분석된다. 구체적으로 근사 이산-시간 모델들의 상태 사이의 비정합의 크기가 충분히 작으면 재설계된 디지털 제어 퍼지 시스템의 평형점은 점근적 안정함을 보인다. 또한 이러한 비정합이 영으로 수렴함에 따라 재설계된 디지털 제어 퍼지 시스템과 주어진 아날로그 제어시스템 사이의 비정합은 매우 작아짐을 보인다.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.6
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• pp.753-758
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• 2006

We present the development of the digital fuzzy controller for maximum power regulation. A hybrid system that comprises wind and photovoltaic generation subsystems, and battery bank is developed in this paper. We use Takaki-Sugeno (T-S) fuzzy model to deal with the power regulation problem, since each power generator has complex nonlinear terms. The problem for regulation control can be simplified into a stabilization one. Also, in order to utilize the advanced digital device, we perform the intelligent digital redesign method. Finally, the performance of the proposed controller is extensively assessed through computer simulation.