• Title/Summary/Keyword: adaptive identification

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LP-Based Blind Adaptive Channel Identification and Equalization with Phase Offset Compensation

  • Ahn, Kyung-Sseung;Baik, Heung-Ki
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.4C
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    • pp.384-391
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    • 2003
  • Blind channel identification and equalization attempt to identify the communication channel and to remove the inter-symbol interference caused by a communication channel without using any known trainning sequences. In this paper, we propose a blind adaptive channel identification and equalization algorithm with phase offset compensation for single-input multiple-output (SIMO) channel. It is based on the one-step forward multichannel linear prediction error method and can be implemented by an RLS algorithm. Phase offset problem, we use a blind adaptive algorithm called the constant modulus derotator (CMD) algorithm based on condtant modulus algorithm (CMA). Moreover, unlike many known subspace (SS) methods or cross relation (CR) methods, our proposed algorithms do not require channel order estimation. Therefore, our algorithms are robust to channel order mismatch.

Neural network-based control for uneven delay-time systems (인공신경망을 이용한 지연시간이 일정치 않은 시스템의 제어)

  • 이미경;이지홍
    • 제어로봇시스템학회:학술대회논문집
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    • 1997.10a
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    • pp.446-449
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    • 1997
  • We propose a control law in discrete time domain of the bilateral feedback teleoperation system using neural network and the reference model type of adaptive control. Different from traditional teleoperation systems, the transmission time delay irregularly changes. The proposed control method controls master and slave systems through identification of master and slave models using neural networks.

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Adaptive Identification of a Time-varying Volterra system using the FWLS (filtered weighted least squares) Algorithm (FWLS 적응 알고리듬을 이용한 시변 볼테라 시스템 식별)

  • Ahn, K.Y.;Jeong, I.S.;Nam, S.W.
    • Proceedings of the KIEE Conference
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    • 2004.05a
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    • pp.3-6
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    • 2004
  • In this paper, the problem of identifying a time-varying nonlinear system in an adaptive way was considered, whereby the time-varying second-order Volterra series was employed to model the system and the filtered weighted least squares (FWLS) algorithm was utilized for the fast parameter tracking capability with low computational burden. Finally, the performance of the proposed approach was demonstrated by providing some computer simulation results.

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Post-processing Technique for Improving the Odor-identification Performance based on E-Nose System

  • Byun, Hyung-Gi
    • Journal of Sensor Science and Technology
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    • v.24 no.6
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    • pp.368-372
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    • 2015
  • In this paper, we proposed a post-processing technique for improving classification performance of electronic nose (E-Nose) system which may be occurred drift signals from sensor array. An adaptive radial basis function network using stochastic gradient (SG) and singular value decomposition (SVD) is applied to process signals from sensor array. Due to drift from sensor's aging and poisoning problems, the final classification results may be showed bias and fluctuations. The predicted classification results with drift are quantized to determine which identification level each class is on. To mitigate sharp fluctuations moving-averaging (MA) technique is applied to quantized identification results. Finally, quantization and some edge correction process are used to decide levels of the fluctuation-smoothed identification results. The proposed technique has been indicated that E-Nose system was shown correct odor identification results even if drift occurred in sensor array. It has been confirmed throughout the experimental works. The enhancements have produced a very robust odor identification capability which can compensate for decision errors induced from drift effects with sensor array in electronic nose system.

ECG Identification Method Using Adaptive Weight Based LMSE Optimization (적응적 가중치를 사용한 LMSE 최적화 기반의 심전도 개인 인식 방법)

  • Kim, Seok-Ho;Kang, Hyun-Soo
    • The Journal of the Korea Contents Association
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    • v.15 no.4
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    • pp.1-8
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    • 2015
  • This paper presents a Electrocardiogram(ECG) identification method using adaptive weight based on Least Mean Square Error(LMSE) optimization. With a preprocessing for noise suppression, we extracts the average ECG signal and its standard deviation at every time instant. Then the extracted information is stored in database. ECG identification is achieved by matching an input ECG signal with the information in database. In computing the matching scores, the standard deviation is used. The scores are computed by applying adaptive weights to the values of the input signal over all time instants. The adaptive weight consists of two terms. The first term is the inverse of the standard deviation of an input signal. The second term is the proportional one to the standard deviation between user SAECGs stored in the DB. Experimental results show up to 100% recognition rate for 32 registered people.

Adaptive Noise Cancelling in ECG Signals Using System Identification Concepts (System Identification 개념을 이용한 ECG 신호의 적응 잡음 제거)

  • Nam, Hyun-Do;Ahn, Dong-Jun
    • Proceedings of the KOSOMBE Conference
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    • v.1993 no.05
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    • pp.74-77
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    • 1993
  • Estimation and removal of power line interference in the electrocardiogram using adaptive noise cancelling techniques is presented. The system identification concepts are used to design the noise cancelling filter and the prediction error method is used to adjust filter coefficients. Computer simulation were performed to compare this method with the Lekov's method.

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Online structural identification by Teager Energy Operator and blind source separation

  • Ghasemi, Vida;Amini, Fereidoun
    • Smart Structures and Systems
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    • v.26 no.2
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    • pp.135-146
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    • 2020
  • This paper deals with an application of adaptive blind source separation (BSS) method, equivariant adaptive separation via independence (EASI), and Teager Energy Operator (TEO) for online identification of structural modal parameters. The aim of adaptive BSS methods is recovering a set of independent sources from their unknown linear mixtures in each step when a new sample is received. In the proposed approach, firstly, the EASI method is used to decompose structural responses into independent sources at each instance. Secondly, the TEO based demodulation method with discrete energy separation algorithm (DESA-1) is applied to each independent source, and the instantaneous frequencies and damping ratios are extracted. The DESA-1 method can provide the fast time response and has high resolution so it is suitable for online problems. This paper also compares the performance of DESA-1 algorithm with Hilbert transform (HT) method. Compared to HT method, the DESA-1 method requires smaller amounts of samples to estimate and has a smaller computational complexity and faster adaption due to instantaneous characteristic. Furthermore, due to high resolution of the DESA-1 algorithm, it is very sensitive to noise and outliers. The effectiveness of the proposed approach has been validated using synthetic examples and a benchmark structure.

Adaptive control based on nonlinear dynamical system

  • Sugisaka, Masanori;Eguchi, Katsumasa
    • 제어로봇시스템학회:학술대회논문집
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    • 1993.10b
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    • pp.401-405
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    • 1993
  • This paper presents a neuro adaptive control method for nonlinear dynamical systems based on artificial neural network systems. The proposed neuro adaptive controller consists of 3 layers artificial neural network system and parallel PD controller. At the early stage in learning or identification process of the system characteristics the PD controller works mainly in order to compensate for the inadequacy of the learning process and then gradually the neuro contrller begins to work instead of the PD controller after the learning process has proceeded. From the simulation studies the neuro adaptive controller is seen to be robust and works effectively for nonlinear dynamical systems from a practical applicational points of view.

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Posterior density estimation for structural parameters using improved differential evolution adaptive Metropolis algorithm

  • Zhou, Jin;Mita, Akira;Mei, Liu
    • Smart Structures and Systems
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    • v.15 no.3
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    • pp.735-749
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    • 2015
  • The major difficulty of using Bayesian probabilistic inference for system identification is to obtain the posterior probability density of parameters conditioned by the measured response. The posterior density of structural parameters indicates how plausible each model is when considering the uncertainty of prediction errors. The Markov chain Monte Carlo (MCMC) method is a widespread medium for posterior inference but its convergence is often slow. The differential evolution adaptive Metropolis-Hasting (DREAM) algorithm boasts a population-based mechanism, which nms multiple different Markov chains simultaneously, and a global optimum exploration ability. This paper proposes an improved differential evolution adaptive Metropolis-Hasting algorithm (IDREAM) strategy to estimate the posterior density of structural parameters. The main benefit of IDREAM is its efficient MCMC simulation through its use of the adaptive Metropolis (AM) method with a mutation strategy for ensuring quick convergence and robust solutions. Its effectiveness was demonstrated in simulations on identifying the structural parameters with limited output data and noise polluted measurements.