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Active noise control systems with time varying sound sensor position

IFAC Proceedings Volumes 2010年第24期43卷 44-47页

作者： Malgorzata I. Michalczyk Institute of Automatic Control Silesian University of Technology Gliwice Poland

The paper summarizes the research on a special class of digital sound processing systems with time varying sound sensor position, conducted in the Institute of Automatic Control, Silesian University of Technology, Gliwice, Poland. These are adaptive active noise control (ANC) systems creating zones of quiet around a microphone, position of which is being changed in enclosure. They use lms-based adaptive control algorithm, which is parameterized with a model of the so called secondary path. The problem arises when the microphone position is changed during the ANC system operation, because secondary path modeling errors arise. They, in some cases can be coped by the adaptive control algorithm itself, however, in other cases an additional, on-line identification routine has to be used to update secondary path model. These two situations are the subject of the presented research.

关键词： Active noise control adaptive algorithms lms algorithm parameterization

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Adaptive Channel Estimation in MIMO-OFDM for Indoor and Outdoor Environments 2

Adaptive Channel Estimation in MIMO-OFDM for Indoor and Outd...

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2nd IEEE International Conference on Wireless Communications, Signal Processing and Networking (WiSPNET)

作者： Ghosh, Monalisa Srinivasarao, C. Sahoo, Harish Kumar IIIT Bhubaneswar Dept Elect & Commun Engn Bhubaneswar 751003 India VSSUT Dept Elect & Commun Burla 768018 India

ISBN: (纸本)9781509044429

With the rapid change in wireless communication technologies, there is always a demand for higher data rates, improved system capacity and service quality. Several technologies and standards have been developed to provide services to the end users. To find out a solution to meet these challenges, channel modeling and estimation of channel state information play a vital role in communication system design. However, due to the adverse effects of channel fading and the Doppler shifts caused by user mobility, channel modeling and estimation of channel parameters is quite difficult. Adaptive modeling for indoor and outdoor channels is an efficient approach to track the time-varying and fading behavior of the channels. This paper addresses the problem of channel estimation in a MIMO-OFDM environment with different indoor and outdoor channel models. The performance of the adaptive estimation model is evaluated through comparison results with the inclusion of sparsity and block processing to conventional Least Mean Square (lms) algorithm.

关键词： Indoor channel Outdoor channel MIMO-OFDM (multiple input multiple output-orthogonal frequency division multiplexing) lms algorithm

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Observer design for nonlinear system

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IFAC Proceedings Volumes 2004年第12期37卷 105-109页

作者： Koichi Hidaka Tokyo Denki University Kanda-Nishiki-cho Chiyoda-ku Tokyo 101-8457 Japan

A design method is presented that extends the least mean squared (lms) algorithm of time–varying parameters which incorporate an internal model. The aim is to track the varying parameters of linear regression models in situations where regressors have not only slowly changing parameters but also rapidly time–varying ones. This algorithm is given from the standpoint that a change in a varying parameter can be approximated as a polynomial function of time with a finite degree. Under this assumption, the proposed algorithm includes an internal model of the polynomial function in a conventional lms algorithm so as to compensate the influence of the varying parameters. The design method is based on a loop transformation for the dynamics and small–gain theorem. Furthermore, a sufficient condition for assuring stability of the proposed algorithm is given by the output strictly passive and small–gain theorem. Compared with conventional lms adaptive algorithms, the tracking performance of varying parameters improves in numerical simulations.

关键词： time–varying parameter internal model lms algorithm output strictly passive

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Single stimulus evoked potential estimation using adaptive noise cancelling with reference alignment

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Revista Tecnica de la Facultad de Ingenieria Universidad del Zulia 1998年第2期21卷 124-130页

作者： Stefanelli, Maria Cristi D'Alvano, Francisco Regidor, Juan Claudio de Perez, Trina Adrian Grupo de Procesamiento de Senates Departamento de Electrónica y Circuitos Universidad Simón Bolívar Caracas Apartado 89000 Venezuela

The objective of this work is to improve Evoked Potential (EP) estimation trough the use of an adaptive noise canceller with an enhanced reference signal. Averaging several EPs is a common method;it produces better results when the signal has been `period-to-period' aligned by the maximization of its cross-correlation with a pattern signal. A disadvantage of the averaging method is the large number of stimuli needed to get a good visualization of a useful EP. We use a two channel adaptive canceller to obtain single stimulus evoked potentials. The canceller reference signal is the quasi-periodic extension of an average EP over a few periods, aligned by cross-correlating it with the primary signal. The Widrow-Hoff lms algorithm is used to determine the filter weights by the noisy steepest descent method. The described technique was applied to simulated signals based on actual registers obtained from visually stimulated subjects. The proposed adaptive cancellation technique provides, with fewer stimuli, better individual estimates, permitting the analysis of the EPs variability between stimuli.

关键词： Adaptive cancelling Averaging Electroencephalography Evoked potential lms algorithm

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IMAGE DENOISING USING WAVELETS TRANSFORM AND ADAPTIVE LEAST MEAN SQUARE METHOD"

IMAGE DENOISING USING WAVELETS TRANSFORM AND ADAPTIVE LEAST ...

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International Conference on Signal Processing, Communication, Power and Embedded System

作者： M. Saritha Sridevi Kulkarni Sowmya Halagatti Dept of Electronics & Communication Engineering Jain College of Engineering Affiliated to VTU Dept of Electronics & Communication Engineering Angadi Institue of Technology Affiliated to VTU Dept of Electronics & Communication Engineering SGBIT Affiliated to VTU

ISBN: (纸本)9781509046218

The wavelet Shrinkage is one of the nonlinear signal denoising method to remove Speckle noise by shrinking the empirical wavelet coefficients in the wavelet domain. In this paper, we propose the adaptive wavelet shrinkage which updates the threshold levels adaptively by Least Mean Square (lms) type algorithm according to the reference signal. The adaptive wavelet Shrinkage Method is robust and it is also easy to control the filter action by modifying the threshold levels directly.

关键词： lms algorithm Speckle Synthetic Aperture Radar (SAR) Adaptive thresholding wavelets

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Design of a Total Monitoring System for Air Drilling Process

Design of a Total Monitoring System for Air Drilling Process

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2013 International Conference on MEMS and Mechanics(MEMSM 2013)

作者： Hao Jiang Hanxiang Wang Wenjian Lan Jian Zhang College of Mechanical and Electronic Engineering China University of Petroleum (East China)

ISBN: (纸本)9781627489256

To ensure the normal drilling and well site safety, a monitoring system is necessary in air drilling to monitor the real-time information in total drilling. By using the lms algorithm and adaptive delayed transversal filter, a mathematical model of underground blasting monitoring is established, and an information monitoring system is also developed based on wireless communication and field bus technologies. The system is characterized by miniaturization, lower cost, convenient operation and transportation, powerful function. The experiment results show that this system can not only provide accurate air drilling parameters and stratum information, but also can monitor the real-time contents of flammable, explosive and toxic gas, which provides a guide for the identify of water-oil-gas layer, supervising drilling and preventing the occurrence of safety accidents in well site.

关键词： Air drilling Wireless communication MWD lms algorithm Safety monitoring

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A TRANSIENT ANALYSIS FOR THE CONVEX COMBINATION OF TWO ADAPTIVE FILTERS WITH TRANSFER OF COEFFICIENTS

A TRANSIENT ANALYSIS FOR THE CONVEX COMBINATION OF TWO ADAPT...

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IEEE International Conference on Acoustics, Speech, and Signal Processing

作者： Magno T. M. Silva Vitor H. Nascimento Jeronimo Arenas-Garcia University of Sao Paulo Brazil Univ. Carlos III de Madrid Spain

ISBN: (纸本)9781424442959

This paper proposes an improved model for the transient of convex combinations of adaptive filters. A previous model, based on a first-order Taylor series approximation of the nonlinear functions that appear in convex combinations, tended to overestimate the variance of the auxiliary variable used to estimate the mixing parameter. In this paper, we apply a second-order Taylor approximation that improves these estimates, and obtains better agreement with simulations. In addition, we also extend the model to include a simple mechanism for the transfer of coefficients between the constituent filters, a procedure that greatly improves the convergence of the overall filter, and provide an expression to select the free parameter used in such a scheme.

关键词： Adaptive filters convex combination transient analysis lms algorithm

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Adaptive Tracking of Ambient System Oscillations by Nonstationary RLS Techniques

Adaptive Tracking of Ambient System Oscillations by Nonstati...

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IEEE Power and Energy Society General Meeting

作者： I. Moreno A. R. Messina Department of Electrical Engineering Cinvestav

ISBN: (纸本)9781457710001

Measured ambient data in power system are known to exhibit noisy, nonstationarity fluctuations resulting primarily from small magnitude, random changes in load. Accounting for stochastic and time-varying features can provide a better description of the data and result in improved estimation algorithms. In this paper, a new hybrid algorithm combining a recursive least-square (RLS) algorithm and a Kalman filter described by a random walk correlation model is proposed to characterize the time evolution of ambient system oscillations. Extensions and generalizations to current RLS algorithms to deal with nonstationarity are discussed and the relationship between Kalman filter parameters and RLS algorithms is analyzed. Examples of the developed procedures to track the evolving dynamics of critical system modes in both simulated and measured data are presented. Comparisons with well-established approaches such as the exponentially-weighted RLS algorithm, RLS algorithms with adaptive memory, least-mean squares (lms) algorithms and normalized lms algorithms demonstrate the accuracy of the proposed procedure.

关键词： Ambient power system data Kalman filtering lms algorithm RLS algorithm Least mean square algorithm Restless Legs Syndrome Kalman filtering Adaptive tracking Kalman filters algorithms

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Adaptive decision feedback equalizer using the delta operator

Adaptive decision feedback equalizer using the delta operato...

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6th World Congress on Intelligent Control and Automation

作者： Zhang, Duanjin Liu, Xia Zhang, Wenying Zhengzhou Univ Coll Informat Engn Zhengzhou 450052 Peoples R China

ISBN: (纸本)1424403316

The problem of the delta operator formulated adaptive equalization is considered by the application of the delta operator least mean squares algorithm into the design of adaptive equalizer. The algorithm of adaptive decision feedback equalizer based on the delta operator (Delta-ADFE) is presented, and the updating-parameter expressions of decision feedback equalizer are also given. Simulation results show that the proposed Delta-ADFE algorithm has the better filtering performance and the equalizing effect than that of the traditional ADFE algorithm using the shift operator.

关键词： adaptive filtering Delta operator lms algorithm adaptive decision feedback equalizer

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A Shortcut to Align 3D Images Captured from Multiple Views

A Shortcut to Align 3D Images Captured from Multiple Views

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International Conference on Experimental Mechanics 2008 (ICEM 2008)

作者： Wei Heng,Hao Wang National Mobile Communications Research Laboratory,Southeast University,Nanjing,China

In order to get whole shape of an object,lots of parts of 3D images need to be captured from multiple views and aligned into a same 3D *** usually involves in both complex software process and expensive hardware system.

关键词： alignment 3D images turntable calibration lms algorithm

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