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Fast blind equalization using complex-valued MLP

NEURAL PROCESSING LETTERS 2005年第3期21卷 215-225页

作者： Pandey, R Natl Inst Technol Dept Elect & Commun Engn Kurukshetra Haryana India

The blind equalizers based on complex valued feedforward neural networks, for linear and nonlinear communication channels, yield better performance as compared to linear equalizers. The learning algorithms are, generally, based on stochastic gradient descent, as they are simple to implement. However, these algorithms show a slow convergence rate. In the blind equalization problem, the unavailability of the desired output signal and the presence of nonlinear activation functions make the application of recursive least squares algorithm difficult. In this letter, a new scheme using recursive least squares algorithm is proposed for blind equalization. The learning of weights of the output layer is obtained by using a modified version of constant modulus algorithm cost function. For the learning of weights of hidden layer neuron space adaptation approach is used. The proposed scheme results in faster convergence of the equalizer.

关键词： blind equalization complex-valued feedforward neural network constant modulus algorithm recursive least square algorithm stochastic gradient descent algorithm

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Foetal ECG extraction using non-linear adaptive noise canceller with multiple primary channels

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IET SIGNAL PROCESSING 2018年第2期12卷 219-227页

作者： Ma, Yaping Xiao, Yegui Wei, Guo Sun, Jinwei Harbin Inst Technol Dept Automat Testing & Control Harbin 150001 Heilongjiang Peoples R China Prefectural Univ Hiroshima Dept Management & Informat Syst Hiroshima 7348558 Japan

A non-linear multi-sensory adaptive noise canceller (ANC, MsANC) with both multi-primary and multi-reference channels is proposed for foetal electrocardiogram (FECG) extraction. The primary channels are connected by a linear combiner (LC) whose output serves as a primary signal for the whole MsANC. A finite impulse response (FIR) filter or a non-linear filter [a Volterra filter, or an FIR filter plus a functional link artificial neural network (FLANN), or an FIR filter plus a generalised FLANN] is placed in each reference channel to approximate the linear and non-linear mappings between the chest maternal ECG (ANC reference signal) and the abdominal ECG (ANC primary signal). The LC connecting the primary channels is updated by a constrained recursive least square algorithm, while the linear and non-linear filters placed in reference channels are updated in a least mean square sense. Two real datasets derived from the Physionet non-invasive FECG database as well as the DaISy database are used to show the effectiveness of the proposed MsANC. Experimental results have revealed that the proposed MsANC results in considerable performance improvement as the number of primary channels is increased in comparison with existing ANCs with a single primary channel.

关键词： electrocardiography medical signal processing FIR filters nonlinear filters least squares approximations foetal ECG extraction nonlinear adaptive noise canceller multiprimary and multireference channels foetal electrocardiogram extraction non-linear filter FIR filter Volterra filter functional link artificial neural network FLANN reference channel ANC reference signal abdominal ECG recursive least square algorithm least mean square sense Physionet non-invasive FECG database

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Design and Implementation of Parameter Estimation and Start Control of Brushless Synchronous Starter/Generators Under Sudden Excitation Change

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IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS 2020年第5期67卷 3551-3561页

作者： Mao, Shuai Liu, Weiguo Jiao, Ningfei Luo, Guangzhao Jiang, Yu Hu, Ying Northwestern Polytech Univ Shaanxi Key Lab Small & Special Elect Machine & D Xian 710072 Peoples R China AVIC Shaanxi Aero Elect Co Ltd Xian 710065 Peoples R China Southwest Minzu Univ Coll Elect & Informat Engn Chengdu 610041 Peoples R China

The stator winding structure of the main exciter of the brushless synchronous starter/generator (BSSG) is changed at high speed for flux weakening, leading to a sudden excitation decrease of the main generator (MG) of BSSG. Consequently, when proportional-integral (PI) current loop-based control strategies are applied, large current overshoots will occur due to the lack of fast current control ability. This paper adopts model predictive current control (MPCC) to replace PI current control for a better dynamic performance. Besides, a parameter estimation scheme, based on the recursive least square (RLS) algorithm, is proposed to provide MG parameters for MPCC. An effectiveness analysis of the RLS algorithm is performed and two rules are given. According to the two rules, rather than the parameter dynamic characteristics adopted by traditional methods, three MG parameters, dq-axes inductances, and excitation flux linkage are estimated with two decoupled RLS estimators. In addition, a method is proposed to adjust the forgetting factor to track fast changing parameters of MG when the excitation changes suddenly. With the estimated parameters, MPCC is conducted to start BSSG. Experimental results show that fast current control of MG is achieved and large current overshoots caused by the sudden excitation change are avoided.

关键词： Stator windings Couplings Windings Parameter estimation Estimation Mathematical model Aircraft starter generator model predictive control parameter estimation recursive least square algorithm

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Online estimation of system parameters for artificial intelligence applications to load frequency control

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IET GENERATION TRANSMISSION & DISTRIBUTION 2011年第8期5卷 895-902页

作者： Chang-Chien, L-R Wu, Y-S Cheng, J-S Natl Cheng Kung Univ Dept Elect Engn Tainan 70101 Taiwan Taiwan Power Co Syst Planning Dept Taipei Taiwan

Making balance between generation and demand is the operating principle of the load frequency control. As the automatic generation control (AGC) has been commissioned to serve load-generation balance for several decades, the developmental roadmap of the AGC is leading to the adaptive or artificial intelligence (AI) applications to the controller design. Among the AI applications, the genetic algorithm (GA) and the fuzzy inference system (FIS) are often adopted to optimise AGC gains under the time-varying system conditions. Relevant studies indicate that the real-time acquisition of system states would be advantageous for AGC to drive system to the optimal condition. However, some of the system parameters are not easily accessible. The object of getting good estimate of system parameters in real-time basis would definitely enhance the performance of the intelligence applications to AGC. This study explores the use of recursive least square algorithm for acquiring the system parameters in real time. As such, a more accurate reference model would be gainfully used in the AI controller design. Issues related to the model validation in the simulation and field test are presented. Following that, the use of the reference model in the GA as well as the FIS applications for the optimal gain scheduling of the AGC is demonstrated.

关键词： AGC load-generation balance Control of electric power systems real-time acquisition FIS application Optimisation techniques automatic generation control Knowledge engineering techniques Power system control genetic algorithm load online estimation genetic algorithms FIS artificial intelligence power generation control least squares approximations optimal gain scheduling Control system analysis and synthesis methods artificial intelligence applications fuzzy inference system application Generating stations and plants Interpolation and function approximation (numerical analysis) recursive least square algorithm parameter estimation fuzzy reasoning control system synthesis Control engineering computing frequency control AI controller design load regulation power engineering computing system parameters recursive estimation Frequency control GA Power engineering computing control engineering computing Other topics in statistics load frequency control

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Application of antenna arrays to mobile communications .2. Beam-forming and direction-of-arrival considerations

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PROCEEDINGS OF THE IEEE 1997年第8期85卷 1195-1245页

作者： Godara, LC School of Electrical Engineering Australian Defence Force Academy University of New South Wales Canberra ACT Australia

Array processing involves manipulation of signals induced on various antenna elements. Its capabilities of steering nulls to reduce cochannel interferences and pointing independent beams toward various mobiles, as well as its ability to provide estimates of directions of radiating sources, make it attractive to a mobile communications system designer. Array processing is expected to play an important role in fulfilling the increased demands of various mobile communications services. Part I of this paper showed how an array could be utilized in different configurations to improve the performance of mobile communications systems, with references to various studies where feasibility of an array system for mobile communications is considered. This paper provides a comprehensive and detailed treatment of different beam-forming schemes, adaptive algorithms tl? adjust the required weighting on antennas, direction-of-arrival estimation methods-including their performance comparison-and effects of errors on the performance of an array system, as well as schemes to alleviate them. This paper brings together almost all aspects of array signal processing. It is presented at a level appropriate to nonexperts in the field and contains a large reference list to probe further.

关键词： beam forming conjugate gradient method eigenstructure methods ESPRIT least square algorithm linear prediction method maximum entropy maximum likelihood method minimum norm mobile communications multipath arrivals MU-SIC MVDR estimator neural networks recursive least square algorithm weighted subspace fitting

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Adaptive pulsar time delay estimation using wavelet-based RLS

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OPTIK 2018年 171卷 266-276页

作者： Kang, Zhiwei He, Hongcai Liu, Jin Ma, Xin Gui, Mingzhen Hunan Univ Coll Comp Sci & Elect Engn Changsha 410082 Hunan Peoples R China Wuhan Univ Sci & Technol Coll Informat Sci & Engn Wuhan 430081 Hubei Peoples R China Wuhan Univ Sci & Technol Minist Educ Engn Res Ctr Met Automat & Measurement Technol Wuhan 430081 Hubei Peoples R China Beihang Univ Coll Instrument Sci & Opto Elect Engn Beijing 100191 Peoples R China

Pulsar time delay needs to be quickly and accurately estimated. In this study, a novel pulsar time delay estimation (PTDE) method based on the wavelet transform and the recursive least squares (RLS) is proposed because of its good robustness and fast convergence of the RLS algorithm. However, the PTDE based on the RLS algorithm (RLSPTDE) leads to high complexity. To address this problem, we initially perform multilevel Haar wavelet transform on the pulsar profile to obtain low-frequency signal. Then, according to the low frequency signal, the adaptive filter based on the RLS algorithm is used to obtain the pre-estimated time delay value. Finally, according to the pre-estimated time delay value, we use the adaptive filter based on the RLS algorithm to perform locally accurate time delay estimation. Certain benefits can be derived from using adaptive filters, especially when underlying parameters, such as signal statistics, are unknown or have changed over time. The theoretical analysis and experimental results show that the proposed method can reduce computational complexity and achieve higher PTDE accuracy than the RLSPTDE.

关键词： Time delay estimation Wavelet transform recursive least square algorithm Pulsar navigation Adaptive filter

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A battery ageing model used in stand alone PV systems

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JOURNAL OF POWER SOURCES 2002年第1期112卷 49-53页

作者： Cherif, A Jraidi, M Dhouib, A ENIT Lab Energet Tunis 1002 Tunisia

The authors present a new model for the ageing of a lead-acid battery which is based on the initial model of Shepherd. The proposed model allows to predict temporal variations of the Shepherd coefficients and to control the deterioration of the battery parameters and performances. The model validation has been realised by the recursive least square (RLS) algorithm by using long-term measurements under several solicitations. This study will improve the storage section of stand-alone photovoltaic systems and reduce overloads and deep discharges. (C) 2002 Elsevier Science B.V. All rights reserved.

关键词： shepherd model recursive least square algorithm less battery storage system

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Technique to Adjust Adaptive Digital Filter Coefficients in Residue Number System Based Filters

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IEEE ACCESS 2021年 9卷 82402-82416页

作者： Kaplun, Dmitrii Voznesensky, Alexander Veligosha, Alexander V. Kalmykov, Igor A. Sarma, Kandarpa Kumar St Petersburg Electrotech Univ LETI Dept Automat & Control Proc St Petersburg 197376 Russia Mil Acad Strateg Missile Forces Dept 52 Serpukhov 142210 Russia North Caucasus Fed Univ Dept Informat Secur Automated Syst Stavropol 355009 Russia Gauhati Univ Dept Elect & Commun Engn Gauhati 781014 India

The paper discusses adaptive filtering using least Mean square (LMS) and recursive least square (RLS) algorithms. An algorithm for adjusting the coefficients of an adaptive digital filter in the Residue Number System and a procedure of developed algorithm applying depending on filter length and signal length are proposed. Mathematical modeling of the considered algorithms is performed. Examples are presented to demonstrate how the proposed technique can help the designer in the adjustment of the filter coefficients without the need for extensive trial-and-error procedures. The analysis of the denoising quality and computational complexity is made. Synthetic and real data (earthquake recording) were used while testing. The proposed algorithm surpasses the existing ones like LMS and RLS, and their modifications in a number of parameters: adaptation (denoising) quality, ease of implementation, execution time. The main difference between the developed algorithm is the sequential adaptation of each coefficient with zero error. In the known algorithms, the entire vector of coefficients is iteratively adapted, with some specified accuracy. The iterations (steps) number is determined by the input signal length for all algorithms.

关键词： Digital filters Signal processing algorithms Filtering algorithms Wiener filters Finite impulse response filters Electronic mail Approximation algorithms Adaptive digital filter residue number system least mean square algorithm recursive least square algorithm denoising quality computational complexity

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Adaptive handover algorithm in heterogeneous femtocellular networks based on received signal strength and signal-to-interference-plus-noise ratio prediction

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IET COMMUNICATIONS 2014年第17期8卷 3061-3071页

作者： Kalbkhani, Hashem Yousefi, Saleh Shayesteh, Mahrokh G. Urmia Univ Dept Elect Engn Orumiyeh Iran Urmia Univ Dept Comp Engn Orumiyeh Iran Sharif Univ Technol ACRI Wireless Res Lab Dept Elect Engn Tehran Iran

In this study, an efficient handover algorithm based on the received signal strength (RSS) prediction is presented for two-tier macro-femtocell networks in which, because of the fading effects of channel and short coverage range of femtocells, ping-pong handovers may take place. In the proposed approach, first each mobile station (MS) uses the recursive least square algorithm for predicting the RSS from the candidate base stations (BSs) including both femtocell and macrocell BSs. Then, according to the predicted RSS values, several future values of signal-to-interference plus noise ratio (SINR) are calculated. Afterwards, the candidate list of BSs is pruned according to the estimated future SINR values and the predicted RSS of each BS. Finally, the target BS which yields the highest throughput, is opted for handover. Through extensive simulations, the effects of speed of MSs and the density of femtocell BSs on the outage probability (OP), throughput and the ping-pong rate of MSs are studied. The results show that the proposed handover algorithm outperforms the previous ones and improves the throughput of MS while it reduces the OP and the number of ping-pong handovers.

关键词： femtocellular radio mobility management (mobile radio) least squares approximations fading channels telecommunication network reliability prediction theory adaptive received signal strength prediction signal-to-interference plus noise ratio prediction SINR ping-pong handovers heterogeneous femtocellular networks mobile station recursive least square algorithm base stations outage probability channel fading effects prediction-based handover algorithms RSS prediction two-tier macro-femtocell networks

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An adaptive procedure for tool life prediction in face milling

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PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART J-JOURNAL OF ENGINEERING TRIBOLOGY 2011年第J11期225卷 1130-1136页

作者： Zhang, D. D. Beihang Univ Dept Syst Engn Engn Technol Beijing 100191 Peoples R China

Accurate prediction of tool life is essential to guarantee surface quality and economics of cutting operations in face milling. This article presents a procedure for tool life prediction through in-process adaptation of tool wear rate based on indirect measures. The procedure effectively accounts for the uncertainty of tool wear progress owing to the complexity of the machining process. First, sensor fusion of spindle motor current AC and DC portions is taken to estimate the actual tool wear through relevance vector machine. Then, a tool life prediction model relating flank wear with cutting time is proposed for tracking the progress of tool wear under certain cutting settings. Further, a recursive least square algorithm is developed to update the parameters of the tool life prediction model by considering the error between the predicted tool wear and the estimated tool wear. Finally, the updated model capturing the uncertainty of tool wear progress is used to predict tool life in face milling. Tool life experiments validate that the adaptive procedure can quickly track the progress of tool wear, and make more accurate prediction of tool life compared with the procedure with constant model parameters.

关键词： tool condition monitoring relevance vector machine recursive least square algorithm

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