• Transactions on Control, Automation and Systems Engineering
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• 제4권2호
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• pp.114-123
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• 2002

Called VISTA (Variable-stability In-flight Simulator Test Aircraft), the one-of-a-kind NF-l6D has a simulation system that can mimic several aircraft. Though housed in an F-l6 Fighting Falcon airframe, VISTA can also act like the F-15 Eagle or the Navy's F-14 Tomcat. More importantly, such flexibility allows for improved training and consolidation of some sorties. Consequently USAF Test Pilot School students will have an opportunity to learn how to test future integrated cockpits. In this paper we will use the multiple model adaptive estimation (MMAE) and the multiple model adaptive controller (MMAC) techniques to model the aircraft's flight control system containing the longitudinal and lateral-directional axes. Single and dual actuator and sensor failures will also be included in the simulation. White Gaussian noise will be included to simulate the effects of atmospheric disturbances.

• 제어로봇시스템학회논문지
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• 제13권7호
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• pp.609-615
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• 2007

We propose an optimized adaptive PID control scheme. This paper is focused on the development of model reduction as well as a new adoptive control structure (viz. a recursive least square estimation (RLSE) method-based structure) that is constructed with smith-predictor structure and a real time estimator. The estimator adjust parameters of a reduced model in real time. It leads to robust and superb control performance for the noise or variation of parameters of process. Experimental study reveals that the proposed control structure exhibits more superb output performance in comparison to some previous methods.

• 한국음향학회지
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• 제32권6호
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• pp.518-524
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• 2013

본 논문에서는 전밴드(full-band) 적응 필터의 수렴 특성을 개선하기 위해 제안된 정규 부밴드 적응 필터(NSAF)의 성능을 향상시키기 위한 가변 스텝 사이즈 기반의 알고리즘을 제안하였다. 널리 알려진 Kwong의 가변 스텝 사이즈 적응 필터는 간단한 하면서도, 고정된 스텝 사이즈의 적응 필터에 비하여 우수한 성능을 보인다. 그러나 가산잡음이 클 경우, 잡음의 크기에 비례하여 성능이 저하되는 단점이 있다. 본 논문에서는 적응 오차에서 추정된 가산 잡음을 차감한 정규 오차를 이용함으로써 가산 잡음에 의존하지 않는 가변 스텝 사이즈 알고리즘을 제안하였다. 시스템 확인 모델 하에서 컴퓨터 모의 실험을 통하여 제안된 알고리즘이 기존의 알고리즘들에 비하여 정상 및 비정상 환경에서 수렴 특성이 우수함을 보였다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제12권1호
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• pp.75-87
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• 2012

A design paradigm using sequential geometric programming is presented to accurately design CMOS op amps with BSIM3. It is based on new adaptive modeling of transistor parameters through the operating point simulation. This has low modeling cost as well as great simplicity and high accuracy. The short-channel dc, high-frequency small-signal, and short-channel noise models are used to characterize the physical behavior of submicron devices. For low-power and low-voltage design, this paradigm is extended to op amps operating in the subthreshold region. Since the biasing and modeling errors are less than 0.25%, the characteristics of the op amps well match simulation results. In addition, small dependency of design results on initial values indicates that a designed op amp may be close to the global optimum. Finally, the design paradigm is illustrated by optimizing CMOS op amps with accurate transfer function.

• 전자공학회논문지 IE
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• 제47권2호
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• pp.54-59
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• 2010

본 논문은 무선 데이터 네트워크에 적용 가능한 적응 프레임 길이 제어 방식을 가진 데이터 링크 프로토콜을 제안한다. 무선 데이터망은 수시로 변화는 에러 환경에 놓여 있다. 이런 에러 환경에서도 잘 적용할 수 있는 가변 프레임 제어 방식을 제안하고 그 성능을 분석하였다. 2상태 마코프 모델을 이용하여 채널 환경을 모델링하였다. 수치해석방식을 통하여 새롭게 제안한 방식이 다양한 종류의 에러환경에서도 좋은 성능을 발휘할 수 있음을 보여 주었다.

• 한국멀티미디어학회논문지
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• 제8권6호
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• pp.783-789
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• 2005

This paper is proposed a watermarking technique for copyright protection of multimedia contents. We proposed adaptive watermark detection algorithm using stochastic perceptual model and statistical decision method in DMWT(discrete multi wavelet transform) domain. The stochastic perceptual model calculates NVF(noise visibility function) based on statistical characteristic in the DMWT. Watermark detection algorithm used the likelihood ratio depend on Bayes' decision theory by reliable detection measure and Neyman-Pearson criterion. To reduce visual artifact of image, in this paper, adaptively decide the embedding number of watermark based on DMWT, and then the watermark embedding strength differently at edge and texture region and flat region embedded when watermark embedding minimize distortion of image. In experiment results, the proposed statistical decision method based on multiwavelet domain could decide watermark detection.

• 한국정밀공학회지
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• 제18권9호
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• pp.71-81
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• 2001

This paper analyzes the effectiveness of minimizing vibration and sound transmission on/through a thin rectangular plate by both feedback control and hybrid control which combines adaptive feedforward control with a feedback loop. An experimental system identification technique using the matrix-fractional curve-fitting of the frequency response data is introduced for complex shaped structures. This identification technique reduces the model order o the MIMO(Multi-Input Multi-Output) system which simplifies the practical implementation. The adaptive feedforward control uses a Multiple filtered-x LMS(Least Mean Square) algorithm and the feedback control uses a multivariable digital LQG(Linear Quadratic Gaussian) algorithm. Experimental results show that an effective reduction of sound transmission is achieved by the hybrid control scheme when both vibration and noise measurement signals are incorporated in the controller.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 추계학술대회 논문집 학회본부
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• pp.332-334
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• 1994

This paper proposes a robust active noise control (ANC) system. The system constructs filter with a standard model. An adaptive litter, connected to the system in parallel, compensates the modeling error. When the adaptive filter does not work, the proposed system is robust while the conventional system loses the noise control capability. But proposed ANC system shows that the performance is comparable with that of the conventional ANC system under normal conditions.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권7호
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• pp.3095-3111
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• 2018

Spectrum sensing (SS) is one of the fundamental tasks for cognitive radio. In SS, decisions can be made via comparing the test statistics with a threshold. Conventional adaptive algorithms for SS usually adjust their thresholds according to the radio environment. This paper concentrates on the issue of adaptive SS whose threshold is adjusted based on the Markovian behavior of primary user (PU). Moreover, Bayesian cost is adopted as the performance metric to achieve a trade-off between false alarm and missed detection probabilities. Two novel adaptive algorithms, including Markov Bayesian energy detection (MBED) algorithm and IMBED (improved MBED) algorithm, are proposed. Both algorithms model the behavior of PU as a two-state Markov process, with which their thresholds are adaptively adjusted according to the detection results at previous slots. Compared with the existing Bayesian energy detection (BED) algorithm, MBED algorithm can achieve lower Bayesian cost, especially in high signal-to-noise ratio (SNR) regime. Furthermore, it has the advantage of low computational complexity. IMBED algorithm is proposed to alleviate the side effects of detection errors at previous slots. It can reduce Bayesian cost more significantly and in a wider SNR region. Simulation results are provided to illustrate the effectiveness and efficiencies of both algorithms.

• 대한기계학회논문집
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• 제14권3호
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• pp.513-525
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• 1990

본 연구에서는 ARSC의 이론적인 전개에 대해서 주로 설명하고자 한다. 제2 장에서는 ARSC의 구조를 자세히 기술하며, 제3장에 ARSC를 컴퓨터에 이식하기 위한 알 고리즘을 요약하여 제시한다. 또한, ARSC알고리즘이 총체적으로(globally) 수렴하며 안정하다는 이론적 증명에 대하여 제4장에서 언급하며, 마지막으로 제5장에 실시간 시 뮬레이션을 통하여 ARSC의 간단한 적용실례를 들었다. 실제로 본 ARSC는 엔드밀링의 절삭력 적응제어에 적용되었는데, 그 연구결과는 별도로 발표할 예정이다.