• Title/Summary/Keyword: adaptive method

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Channel-adaptive Image Compression for Wireless Transmission

  • Lee, Yun-Gu;Lee, Ki-Hoon
    • IEIE Transactions on Smart Processing and Computing
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    • v.6 no.4
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    • pp.276-280
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    • 2017
  • This paper presents computationally efficient image compression for wireless transmission of high-definition video, to adaptively utilize available channel bandwidth and improve image quality. The method indirectly predicts an unknown available channel bandwidth by monitoring encoder buffer status, and adaptively controls a quantization parameter to fully utilize the bandwidth. Experimental results show that the proposed method is robust to variations in channel bandwidth.

Robust adaptive control for a stable nonminimum phase system (안정한 비최소 위상 시스템의 견실한 적응제어)

  • 최종호;김호찬
    • 제어로봇시스템학회:학술대회논문집
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    • 1988.10a
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    • pp.255-260
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    • 1988
  • A robust adaptive control method for a stable nonminimum phase SISO system with unmodelled dynamics is proposed. The robust parameter estimation method of the system with bounded output noise and unmodelled dynamics is employed and a parallel structure is proposed to improve the robustness of adaptive control system. The local stability of the proposed system is shown. Computer simulations are done in order to compare the performance of the proposed structure with the basic structure on various circumstance.

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Zerotree coding with local adaptive threshold (국부 적응 문턱값을 가지는 제로트리 부호화)

  • 엄일규;김유신;김재호
    • Journal of the Korean Institute of Telematics and Electronics S
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    • v.34S no.10
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    • pp.112-119
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    • 1997
  • Zerotreeimage coding is known as a simple and effective image comprssion algorithm. It has the property that the compression is generated in order of improtance. Conventionally, a fixed threshold is applied to the entire wavelet coefficients regardless of frequency and local features of an image. In this paper, we propose a new zerotree coding scheme with adaptive threshold. The adaptive threshold is determined by human visual characteristics. It is shown that the image quality of the proposed method is better than that of the conventional method.

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Self tuning control with offset elimination for nonminimum phase system (비최소 위상 시스템에 대하여 오프셋(offset) 제거 기능을 가진 자기 동조 제어)

  • 나종래;변증남
    • 제어로봇시스템학회:학술대회논문집
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    • 1986.10a
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    • pp.78-82
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    • 1986
  • In the process control applications of self tuning control, a major concern of the control problem is to handle an offset caused by load disturbances and random steps occuring at random instance of time. Conventionally an integrator is incorperated in the forward path of the controller to eliminate such an offset. But this approach causes a difficulty if the adaptive part of the resultant controller is to be evaluated. In this paper a method of analyzing the adaptive system and improving the offset effect is suggested for a class of referance model method in the self tuning adaptive control system.

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Design of Adaptive Observer Applied to M.R.A.C. by Selection of State Variable Filter (상태변수 필터 선정에 의한 적응 관측기의 설계 및 기준모델 적응제어)

  • 홍연찬;김종환;최계근
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.24 no.4
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    • pp.597-602
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    • 1987
  • In this paper, an adaptive observe based upon the exponentially weighted least-squares method is implemented in the design of a model reference adaptive controller for an unknown time-invariant discrete single-input single-output linear plant. A method of selecting the state variable filter is proposed. In this scheme, all the past data are weithted exponentially with the weighting coefficient.

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Model Reference Adaptive Control for Linear System with Improved Convergence Rate-parameter Adaptation Method (선형시스템을 위한 개선된 수렴속도를 갖는 기준모델 적응제어)

  • Lim, Kye-Young
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.37 no.12
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    • pp.884-893
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    • 1988
  • Adaptive controllers for linear unknown coefficient system, that is corrupted by disturbance, are designed by parameter adaptation model reference adaptive control(MRAC). This design is stemmed from the Lyapunov direct method. To reduce the model following error and to improve the convergence rate of the design, an indirect-suboptimal control law is derived. Proper compensation for the effects of time-varying coefficients and plant disturbance are suggested. In the design procedure no complete identification of unknown coefficients are required.

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An Adaptive Control Method of Robot Manipulators using RBFN (RBFN을 이용한 로봇 매니퓰레이터의 적응제어 방법)

  • 이민중;최영규;박진현
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.420-420
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    • 2000
  • In this paper, we propose an adaptive controller using RBFN(radial basis function network) for robot manipulators The structure of the proposed controller consists of a RBFN and VSC-1 ike control. RBFN is used in order to approximate かon system, and VSC-like control to guarantee robustness On the basis of the Lyapunov stability theorem, we guarantee the stability for the total system. And the learning law of RBFN is established by the Lyapunov method, Finally, we apply the proposed controller to tracking control for a 2 link SCARA type robot manipulator.

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An Adaptive Neuro-Fuzzy System Using Fuzzy Min-Max Networks (퍼지 Min-Max 네트워크를 이용한 적응 뉴로-퍼지 시스템)

  • 곽근창;김성수;김주식;유정웅
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.367-367
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    • 2000
  • In this paper, an Adaptive neuro-fuzzy Inference system(ANFIS) using fuzzy min-max network(FMMN) is proposed. Fuzzy min-max network classifier that utilizes fuzzy sets as pattern classes is described. Each fuzzy set is an aggregation of fuzzy set hyperboxes. Here, the proposed method transforms the hyperboxes into gaussian membership functions, where the transformed membership functions are inserted for generating fuzzy rules of ANFIS. Finally, we applied the proposed method to the classification problem of iris data and obtained a better performance than previous works.

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Boundary stress resolution and its application to adaptive finite element analysis

  • Deng, Jianhui;Zheng, Hong;Ge, Xiurun
    • Structural Engineering and Mechanics
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    • v.6 no.1
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    • pp.115-124
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    • 1998
  • A novel boundary stress resolution method is suggested in this paper, which is based upon the displacements of finite element analysis and of high precision with stress boundary condition strictly satisfied. The method is used to modify the Zienkiewicz-Zhu ($Z^2$) a posteriori error estimator and for the h-version adaptive finite element analysis of crack problems. Successful results are obtained.

Adaptive Coefficient Scanning Based on the Intra Prediction Mode

  • Choi, Byeong-Doo;Kim, Jin-Hyung;Ko, Sung-Jea
    • ETRI Journal
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    • v.29 no.5
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    • pp.694-696
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    • 2007
  • This letter presents an adaptive coefficient scanning method for intra mode coding in H.264. The proposed adaptive scanning uses six alternative scanning orders based on the intra prediction mode. Experimental results show that the proposed method improves the coding efficiency up to 3% compared to conventional scanning methods without additional computations.

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