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Lossless image compression by lms adaptive filter banks

SIGNAL PROCESSING 2001年第2期81卷 447-450页

作者： Öktem, R Çetin, AE Gerek, ON Öktem, L Egiazarian, K Bilkent Univ Dept Elect & Elect Engn TR-06533 Bilkent Ankara Turkey

A lossless image compression algorithm based on adaptive subband decomposition is proposed. The subband decomposition is achieved by a two-channel lms adaptive filter bank. The resulting coefficients are lossy coded first, and then the residual error between the lossy and error-free coefficients is compressed. The locations and the magnitudes of the nonzero coefficients are encoded separately by an hierarchical enumerative coding method. The locations of the nonzero coefficients in children bands are predicted from those in the parent band. The proposed compression algorithm, on the average, provides higher compression ratios than the state-of-the-art methods. (C) 2001 Elsevier Science B.V. All rights reserved.

关键词： adaptive subband decomposition lossless image compression lms algorithm

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Performance evaluation of finite precision lms adaptive filters using probability density approach

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Journal of the Institution of Electronics and Telecommunication Engineers 1992年第4期38卷 192-192页

作者： Patra, J.C. Panda, G.

Least Mean Square (lms) algorithm is the most popular adaptive algorithm (AA) for realization of a digital adaptive filter (AF). In digital implementation of AF, finite word length hardware is unavoidable. This finite precision (FP) effect on the performance of the AF is crucial in the sense that, if proper word length is not used the performance in terms of the mean square error (MSE) of the filter degrades substantially. In this paper, a new approach based on the probability theory is used to analyze the FP effect of the lms based finite impulse response (FIR) AF. An expression of the adaptation failure in terms of word length and the step size is derived. Simulation study of a FP lms adaptive equalizer is carried out to demonstrate and verify this effect. This study provides an important guide-line to the designers for selecting the optimum word length for a specific application for a given MSE criterion.

关键词： Adaptive filter Probability of adaptation failure lms algorithm

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Enhanced lms for Online Frequency Estimation under Wide Spectrum Disturbances 10

Enhanced LMS for Online Frequency Estimation under Wide Spec...

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IEEE 10th Annual Information Technology, Electronics and Mobile Communication Conference (IEMCON)

作者： Moreira, Mariana Geny Vale-Cardoso, Adriano S. Martins, Carlos H. N. Leles, Michel C. R. Univ Fed Sao Joao del Rei Dept Technol Ouro Branco Brazil ATDC Georgia Tech VeriSolut Atlanta GA USA

ISBN: (纸本)9781728125305

A large effort has been made for improving the quality of electric power in the last years. More often, the studies concern over methods and techniques to enhance monitoring systems. One of the major relevance is the fundamental frequency estimation, especially in the presence of harmonics and interharmonics disturbances. This paper focuses on the accurate frequency estimation of power signals corrupted by stationary white noise and harmonics and interharmonics disturbances using the least mean square (lms) method, a simple and well-known technique. The effects of these disturbances are studied in an extensive set of simulation results which demonstrate the feasibility of the lms method to estimate the fundamental frequency of corrupted signals.

关键词： least mean square (lms) digital signal processing power quality frequency estimation interharmonics harmonics disturbances single-phase grid voltage parameters estimation power grid harmonic analysis parameter estimation lms algorithm microgrid

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Design of an extended lms-type adaptive filter using semidefinite programming

Design of an extended LMS-type adaptive filter using semidef...

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IEEE International Conference on Industrial Technology

作者： Wakasa, Y Izumi, T Yamamoto, Y Yamaguchi Univ Fac Engn Dept Elect & Elect Engn Ube Yamaguchi 7558611 Japan

ISBN: (纸本)0780376579

Adaptive estimation mechanism makes an important role in robot control since it is necessary to estimate changes of environment of a robot for the sake of adequate control. The least mean square (lms) algorithm is one of such adaptive estimation algorithms, and has been used as an effective and popular approach in signal processing because of its simple structure and low computational complexity. This paper proposes a design method for an lms-type algorithm which is robust in some sense and converges faster than the conventional lms algorithms. By means of recent robust control theory, the design problem is reduced to a semidefinite program which is an efficiently solvable optimization problem. Numerical examples are provided to illustrate the effectiveness of the proposed method.

关键词： adaptive filters lms algorithm semidefinite programming

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lms-Based Digital Pre-Equalizer for Cognitive RoF System 18

LMS-Based Digital Pre-Equalizer for Cognitive RoF System

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18th International Conference on Transparent Optical Networks (ICTON)

作者： Rebhi, Sarra Barrak, Rim Menif, Mourad Higher Sch Commun Tunis GRESCOM Lab Ariana Tunisia

ISBN: (纸本)9781509014675

The development of reconfigurable and high throughput architectures is the utmost target for researchers in the field of Radio over Fiber (RoF). In this paper, we developed a cognitive radio over fiber system lined up with Software Defined Networking owing to improve the quality of transport using a pre-equalization technique. The pre-equalization technique is based on Least Mean Square (lms) algorithm. It is used to compensate the optical link performance degradation in the RoF system. The simulation results of the overall Bit Error Rate (BER) and the Q factor attest of high system performance improvement.

关键词： radio over fiber performances improvement pre-equalization lms algorithm high spectral efficiency high throughputs

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Simulation and Analysis of Nonlinear System Identification using the lms Volterra Filter

Simulation and Analysis of Nonlinear System Identification u...

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7th International Conference on MEMS, NANO and Smart Systems (ICMENS 2011)

作者： Rai, Amrita Kohli, A. K. Thapar Univ Elect & Commun Dept Patiala 147004 Punjab India

ISBN: (纸本)9783037853122

Nonlinear system Identification based on Volterra filter are widely used for the nonlinearity identification in various application. A standard algorithm for lms-Volterra filter for system identification simulation, tested with several convergence criteria is presented in this paper. We analyze the steady-state mean square error (MSE) convergence of the lms algorithm when random functions are used as reference inputs. In this paper, we make a more precise analysis using the deterministic nature of the reference inputs and their time-variant correlation matrix. Simulations performed under MATLAB show remarkable differences between convergence criteria with various value of the step size. Along with that the least mean squared (lms) adaptive filtering algorithm may experience uncontrolled parameter drift when its input signal is not persistently exciting, leading to serious consequences when implemented with finite word-length. The second order lms Volterra filter with variable step size for system identification are analyzed and comparing the theoretical value with experimental value. Copyright (C) 2009 IFSA.

关键词： Volterra Kernel Estimation Nonlinear System Identification lms algorithm Convergence Criteria

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lms-based Notch Filter for AMB Unbalance Compensation Control

LMS-based Notch Filter for AMB Unbalance Compensation Contro...

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2nd International Conference on Energy, Environment and Sustainable Development (EESD 2012)

作者： Li, Huailiang Wang, Yusheng Zhang, Yang China Elect Power Res Inst Dept Elect Power Consumpt & Energy Efficiency Nanjing 210061 Jiangsu Peoples R China

ISBN: (纸本)9783037855515

The stability and other properties of the active magnetic bearing system influenced by periodic vibration impact with the same frequency of the rotor speed are analyzed. Firstly, on the basis of the periodic displacement signal, the filtering theory of least mean square (lms) algorithm and the deficiency of lms algorithm in the application of AMB system, such as frequency mismatch, the relation of step-size and the frequency of displacement signal, and the mutual influence among the step-size length and frequency of the rotor and the PM controller coefficient, etc are studied. And then, a new strategy of variable step-size and real-time switching control with lms and PID combination to filter the sinusoidal displacement signal to achieve adaptive force balance compensation is proposed. Finally, the feasibility of the new method for the adaptive compensation of the vibration of AMB system is tested by the experimental results.

关键词： Active magnetic bearing lms algorithm frequency mismatch bandwidth AFB compensation adaptive filter

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Performance analysis of the lms Fourier Analyzer in the presence of frequency mismatch

Performance analysis of the LMS Fourier Analyzer in the pres...

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5th International Symposium on Instrumentation and Control Technology

作者： Xiao, YG Ikuta, A Ma, LY Hiroshima Prefectural Womens Univ Minami Ku Hiroshima 7348558 Japan

ISBN: (纸本)0819451371

The statistical performances of the conventional adaptive Fourier analyzers, such as the lms, the RLS algorithms and so on, may degenerate significantly, if the signal frequencies given to the analyzers differ from the true signal frequencies. This difference is referred to as frequency mismatch (FM). In this paper, we analyze extensively the performance of the conventional lms Fourier analyzer in the presence of FM. We derive its dynamics and steady-state properties in detail. The optimum step size parameters which minimize the influence of the FM are also derived. Simulations are performed to reveal the validity of the analytical findings.

关键词： adaptive Fourier analysis lms algorithm frequency mismatch convergence MSE

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Effective Adaptive Noise Canceller Design Using Normalized lms 1

Effective Adaptive Noise Canceller Design Using Normalized L...

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1st International Conference on Next Generation Computing Technologies (NGCT)

作者： Kumari, Raj Mehra, Rajesh Shrama, Lalita NITTTR Dept Elect & Commun Engn Chandigarh India NITTTR Chandigarh India Shoolini Univ Solan India

ISBN: (纸本)9781467368094

This paper presents the application of Adaptive filters in noise cancellation during various communication processes, where non-stationary signals are transmitted. Adaptive filter estimates the noise signal and by applying the appropriate weights the estimated noise signal is eliminated from the information. For noise cancellation applications most efficient Adaptive filter algorithms lms and its normalized form Nlms are used and their comparative analysis is done in form of their output power, error power and SNR. In both of the algorithms concept of negative feedback is utilized in the cancellation of noise from the signal and thus both of these are also called negative feedback algorithms. Implementation and analysis is done by applying different step sizes on different order of filter. Order of filter is taken as 4, 8, 12 and then by changing the values of coefficients the graphical and computational analysis is done. Finally an efficient design using Nlms algorithm is implemented where order is taken as 8 and step size 0.2. This results as a low error power (11.7221 db) and a high value of SNR (1.1445) than that of lms algorithms.

关键词： Adaptive Filters Error Power lms algorithm Nlms algorithm SNR

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lms Adaptive Receiver for Uplink Space-Time Coded MC-CDMA Systems

LMS Adaptive Receiver for Uplink Space-Time Coded MC-CDMA Sy...

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12th International Conference on Advanced Communication Technology (ICACT) - lCT for Green Growth and Sustainable Development

作者： Seo, Bangwon Ahn, Jae Young ETRI Mobile Telecommun Res Div Daejeon South Korea

ISBN: (纸本)9788955191455

In this paper, we propose a least mean square (lms) adaptive receiver for uplink multicarrier code-division multiple access (MC-CDMA) systems employing Alamouti's simple space-time block coding (STBC). In general, for the space-time coded systems, there are two filters to be designed, where one is for detecting odd-indexed symbols and the other for even-indexed symbols. In the proposed scheme, the two filters are independently updated and convergence properties such as convergence condition, time constant, and steady-state excess mean-squared error (MSE) are analyzed. Simulation results show that the proposed lms adaptive receiver has higher steady-state signal to interference and noise ratio (SINR) than the lms adaptive receiver for the MC-CDMA system with single transmit antenna while the former shows slower convergence rate than the latter.

关键词： MC-CDMA uplink lms algorithm convergence analysis

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