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Exact analysis of the least-mean-square algorithm with coloured measurement noise

ELECTRONICS LETTERS 2018年第24期54卷 1401-1402页

作者： Lara, Pedro Olinto, Karen da S. Petraglia, Felipe R. Haddad, Diego B. CEFET RJ Rio De Janeiro RJ Brazil Univ Fed Rio de Janeiro Rio de Janeiro RJ Brazil

In general, theoretical analyses of adaptive filtering algorithms employ statistical approximations in order to render the derivations tractable. Among such hypotheses, the statistical independence between the current adaptive coefficients and past input vectors is a very popular one. Unfortunately, this simplification gives rise to discrepancies with respect to empirical results, especially for large values of the step-size parameter. In this Letter, this issue is overcome by the usage of an exact expectation analysis (i.e. a stochastic model that does not employ the above-mentioned independence assumption) of the least-mean-squares adaptive algorithm. The authors analysis is also generalised in order to address the common case of coloured additive noise, an issue that is so far missing from the literature. The accuracy of the advanced model is verified through simulations.

关键词： least mean squares methods adaptive filters filtering theory stochastic processes statistical independence current adaptive coefficients input vectors simplification empirical results step-size parameter exact expectation analysis stochastic model above-mentioned independence assumption least-mean-squares authors analysis coloured additive noise exact analysis least-mean-square algorithm coloured measurement noise general analyses theoretical analyses adaptive filtering algorithms statistical approximations derivations tractable

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Adaptive mandarin morse code recognition using fuzzy support vector machines and a variable degree variable step size least-mean-square algorithm

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JOURNAL OF INFORMATION SCIENCE AND ENGINEERING 2007年第5期23卷 1623-1637页

作者： Yang, Cheng-Hong Huang, Hsiu-Chen Chuang, Li-Yeh Yang, Cheng-Huei Natl Kaohsiung Univ Appl Sci Dept Elect Engn Kaohsiung 807 Taiwan Chiayi Christian Hosp Dept Phys Med & Rehabil Chiayi 539 Taiwan IShou Univ Dept Chem Engn Kaohsiung 840 Taiwan Natl Kaohsiung Marine Univ Dept Elect Commun Engn Kaohsiung 811 Taiwan

Morse code has been shown to be valuable in assistive technology, augmentative and alternative communication, rehabilitation, and education. In this paper, Morse code is selected as a communication adaptive device for persons with various neuromuscular diseases such as amyotrophic lateral sclerosis, multiple sclerosis, and muscular dystrophy. Maintaining a stable typing rate presents a major obstacle to being effective as a communication tool. Therefore, an adaptive automatic recognition method with a high recognition rate is needed. The proposed system uses both fuzzy support vector machines and the variable-degree variable-step-size least-mean-square algorithm. Statistical analyses demonstrated that the proposed method elicited a higher recognition rate than other algorithms in the literature.

关键词： morse code adaptive tool least-mean-square algorithm support vector machines fuzzy theory

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30 YEARS OF ADAPTIVE NEURAL NETWORKS - PERCEPTRON, MADALINE, AND BACKPROPAGATION

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PROCEEDINGS OF THE IEEE 1990年第9期78卷 1415-1442页

作者： WIDROW, B LEHR, MA Dept. of Electr. Eng. Stanford Univ. CA

Fundamental developments in feedforward artificial neural networks from the past thirty years are reviewed. The history, origination, operating characteristics, and basic theory of several supervised neural-network training algorithms (including the perceptron rule, the least-mean-square algorithm, three Madaline rules, and the backpropagation technique) are described. The concept underlying these iterative adaptation algorithms is the minimal disturbance principle, which suggests that during training it is advisable to inject new information into a network in a manner that disturbs stored information to the smallest extent possible. The two principal kinds of online rules that have developed for altering the weights of a network are examined for both single-threshold elements and multielement networks. They are error-correction rules, which alter the weights of a network to correct error in the output response to the present input pattern, and gradient rules, which alter the weights of a network during each pattern presentation by gradient descent with the objective of reducing mean-square error (averaged over all training patterns)

关键词： Madaline adaptive neural networks adaptive systems backpropagation error-correction rules iterative adaptation algorithms iterative methods learning systems least-mean-square algorithm multielement networks neural nets pattern presentation pattern recognition pattern recognition perceptron single-threshold elements training algorithms

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Communication aid system for users with physical impairments

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COMPUTERS & MATHEMATICS WITH APPLICATIONS 2002年第6-7期43卷 901-910页

作者： Yang, CH Chung, PC Chuang, LY Yang, CH Natl Kaohsiung Inst Marine Technol Dept Telecommun & Comp Engn Kaohsiung Taiwan Natl Cheng Kung Univ Dept Elect Engn Tainan 70101 Taiwan I Shou Univ Dept Chem Engn Kaohsiung Taiwan Natl Kaohsiung Univ Appl Sci Dept Elect Engn Kaohsiung Taiwan

For some physically-disabled persons, the conventional computer keyboard may be inappropriate as a usable communication device. They instead require an assistive tool for entering text into a computer or for word-processing for purposes of augmentative and alternative communication in their daily lives. In this study, Morse code is selected as one possible adapted access communication method for persons with impaired hand coordination and limited dexterity. Inherently, a stable switch activation rate is strictly required for the most accurate recognition of Morse code. However, because maintaining a stable switch activation rate is a challenge for many persons who are physically disabled, automatic recognition of Morse code with standardized computer programs is difficult. Therefore, a suitable adaptive automatic recognition method is needed. This study presents a least-mean-square algorithm applied to adaptive Morse code recognition. Four processes axe involved in this adaptive Morse code recognition method: space recognition, tone recognition, adaptive processing, and character recognition. Statistical analyses demonstrated that the recognition rate of the proposed method resulted in an 83% improvement over alternative methods described in previous literature. (C) 2002 Elsevier Science Ltd. All rights reserved.

关键词： Morse code adaptive signal processing least-mean-square algorithm Friedman test multiple comparison test adapted computer access assistive technology

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Performance of fractional delay estimation in joint estimation algorithm dedicated to digital Tx leakage compensation in FDD transceivers

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EURASIP JOURNAL ON WIRELESS COMMUNICATIONS AND NETWORKING 2017年第1期2017卷 1页

作者： Gerzaguet, Robin Ros, Laurent Belveze, Fabrice Brossier, Jean-Marc Univ Rennes 1 IRISA F-38000 Grenoble France GIPSA Lab Image & Signal Dept F-38400 St Martin Dheres France ST Microelect F-38000 Grenoble France

This paper deals with the performance of the fractional delay estimator in the joint complex amplitude/delay estimation algorithm dedicated to digital Tx leakage compensation in FDD transceivers. Such transceivers suffer from transmitter-receiver signal leakage. Combined with non linearity of components in the receiver path, the baseband received signal is impaired by a baseband polluting signal. This baseband polluting term depends on the equivalent Tx leakage channel which models leakages of the receiver path. In (Gerzaguet et al., Digit. Signal Proc 51:35-46, 2016), we have proposed a Tx leakage interference cancellation algorithm based on joint estimation of the complex gain and the fractional delay of the equivalent Tx leakage channel and we have derived the asymptotic performance of the complex gain estimator, that showed the necessity of the fractional delay estimation. In this paper, we propose a comprehensive study of the fractional delay estimation algorithm and its analytic performance. The study is based on the analysis of the S-curve and loop noise variance of the timing error detector, from which an approximation of the asymptotic performance of the joint estimation algorithm is derived.

关键词： Tx leakage FDD transceiver Digital compensation least-mean-square algorithm Joint estimation S-curve

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A Modified RLS algorithm for ICA with Weighted Orthogonal Constraint

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CIRCUITS SYSTEMS AND SIGNAL PROCESSING 2020年第6期39卷 3046-3060页

作者： Jianwei, E. Ye, Jimin Xidian Univ Sch Math & Stat Xian 710071 Shaanxi Peoples R China

Independent component analysis (ICA), as an important data processing technique, is widely employed in many areas. The objective of the ICA is to recover independent components from observed signals. Several algorithms, such as equivariant adaptive separation via independence algorithm, least-mean-square (LMS)-type algorithms and recursive least-squares (RLS)-type learning rules, are proposed to solve the ICA problem. In the present paper, a modified RLS algorithm for ICA with weighted orthogonal constraint is developed to implement source separation based on the local convergence analysis of the available algorithm. Comparative experiment results demonstrate that the proposed algorithm is better than existing learning rules in the aspect of the accuracy of separation and stability.

关键词： Independent component analysis least-mean-square algorithm Recursive least-squares algorithm Weighted orthogonal constraint

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A new Mandarin phonetic morse code recognition method using a variant LMS algorithm

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JOURNAL OF THE CHINESE INSTITUTE OF ENGINEERS 2000年第6期23卷 741-748页

作者： Yang, CH Natl Kaohsiung Univ Appl Sci Dept Elect Engn Kaohsiung 807 Taiwan

The conventional computer keyboard is unable to provide a useable communication device for physically disabled persons with such disabilities as muscle atrophy, cerebral palsy, and severe handicap. In this paper, the Morse code is selected as a communication adaptive device for entering Mandarin phonetic symbols into a computer. Although a stable typing rate is strictly required for an accurate recognition of Mandarin phonetic Morse code, maintaining this rate is a challenge for the disabled. Therefore, a suitable adaptive automatic recognition method is needed. Four processes are involved in this adaptive Mandarin phonetic Morse code recognition method: space recognition, tone recognition, adaptive processing, and character recognition. Experimental results revealed that the recognition rate generated by the proposed method elicited as high as a 90% improvement over alternative methods from the literature.

关键词： morse code adaptive signal processing mandarin phonetic symbols least-mean-square algorithm

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Counter-propagation network with variable degree variable step size LMS for single switch typing recognition

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BIO-MEDICAL MATERIALS AND ENGINEERING 2004年第1期14卷 23-32页

作者： Yang, CH Luo, CH Yang, CH Chuang, LY Natl Kaohsiung Inst Marine Technol Dept Elect Commun Engn Kaohsiung Taiwan Natl Cheng Kung Univ Dept Elect Engn Tainan 70101 Taiwan Ishou Univ Dept Chem Engn Kaohsiung Taiwan Natl Kaohsiung Univ Appl Sci Dept Elect Engn Kaohsiung 807 Taiwan

Morse code is now being harnessed for use in rehabilitation applications of augmentative-alternative communication and assistive technology, including mobility, environmental control and adapted worksite access. In this paper, Morse code is selected as a communication adaptive device for disabled persons who suffer from muscle atrophy, cerebral palsy or other severe handicaps. A stable typing rate is strictly required for Morse code to be effective as a communication tool. This restriction is a major hindrance. Therefore, a switch adaptive automatic recognition method with a high recognition rate is needed. The proposed system combines counter-propagation networks with a variable degree variable step size LMS algorithm. It is divided into five stages: space recognition, tone recognition, learning process, adaptive processing, and character recognition. Statistical analyses demonstrated that the proposed method elicited a better recognition rate in comparison to alternative methods in the literature.

关键词： Morse code adaptive signal processing counter-propagation network least-mean-square algorithm

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Stabilization of a Modified LMS algorithm for Canceling Nonlinear Memory Effects

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 2020年 68卷 3439-3449页

作者： Xiao, Yue-Yu Shanghai Univ Sch Commun & Informat Engn Shanghai 201800 Peoples R China

The least-mean-square (LMS) is promising in a system whose signal statistics are time-varying, and it is preferred in adaptive digital predistortion techniques. In a nonlinear memory system, it is found that the high nonlinearity, the finite sampling rate and the finite number of digits will introduce colored noise that is dependent on signals. In this paper, the long-term stability of the conventional LMS in the presence of signal-dependent noise is analyzed using perturbation analysis. It is revealed that the cumulative effect of the signal-dependent noise may lead to a divergence of the conventional LMS, and a properly selected leaky coefficient is needed to suppress the divergence. Unfortunately, the compensation performance may be harmed by enlarging the leaky coefficient. To address this problem, a modified LMS (MLMS) algorithm is proposed. By adjusting the updating strategy in the iterations, the long-term stability of the algorithm is guaranteed, without harming the linearization performance. Numerical simulations verify that the MLMS outperforms the conventional LMS both in stability and compensation performance.

关键词： Predistortion Stability analysis Gain Low pass filters Signal processing algorithms Numerical stability Nonlinear distortion least-mean-square algorithm stability analysis nonlinear memory effect predistortion system

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VARIABLE-STEP-SIZE LMS algorithm - NEW DEVELOPMENTS AND EXPERIMENTS

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IEE PROCEEDINGS-VISION IMAGE AND SIGNAL PROCESSING 1994年第5期141卷 311-317页

作者： FARHANGBOROUJENY, B Dept. of Electr. Eng. Nat. Univ. of Singapore Singapore

The variable-step-size least-mean-square (VSLMS) algorithm is explored and adopted for tracking of time-varying environments. Two implementations of the VSLMS algorithm are proposed. The emphasis is on the implementations with different step sizes at various taps of the adaptive filter. General analysis of the VSLMS algorithm appears to be somewhat involved. However, for one implementation a limited analysis of the algorithm is found possible. For this implementation it is shown that, when the input samples to the adaptive filter are zero-mean, Gaussian and uncorrelated with one another, the VSLMS algorithm can adapt itself to select the optimum set of step sizes which results in the best-tracking performance. Simulation experiments with the VSLMS algorithm show that, under fairly mild conditions, both of the proposed implementations adapt toward the optimum step sizes.

关键词： ADAPTIVE SIGNAL PROCESSING least-mean-square algorithm ADAPTIVE FILTERS STOCHASTIC GRADIENTS

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