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QUANTIZATION AND OTHER NONLINEAR EFFECTS IN THE LMS adaptive algorithm

ANNALES DES TELECOMMUNICATIONS-ANNALS OF TELECOMMUNICATIONS 1986年第5-6期41卷 295-304页

作者： BERSHAD, NJ SHERWOOD, DT 1.Department of Electrical Engineering University of California 92717 Irvine California USA

Quantization effects in the complexlms adaptive algorithm are studied for two cases. For frequency domain adaptation, the complex scalarlms algorithm is analyzed by modeling the accumulator input quantizer as a memory... 详细信息

Quantization effects in the complex_lms adaptive algorithm are studied for two cases. For frequency domain adaptation, the complex scalarlms algorithm is analyzed by modeling the accumulator input quantizer as a memoryless nonlinearity. For time domainlms adaptation, weight vector adaptation is studied by adding of dither. The dither linearizes the rounding quantizer at each accumulator input. The effects of both the dither and quantization noise on algorithm performance are studied. Results are also presented for an arbitrary nonlinear operation on the data input to the weight update for the real lms algorithm with a gaussian data model. Difference equations are derived and solved for the weight first and second moments. The solutions are used to minimize the mean square error over the choice of nonlinearity for a fixed transient behaviour.

关键词： Signal quantization Non linear effect adaptive algorithm Least squares method Frequency domain method Time domain method Dither Rounding error Quantization noise Signal estimation Random signal adaptive estimation Quantification signal Effet non linéaire algorithme adaptatif Méthode moindre carré Méthode domaine fréquence Méthode domaine temps Tremblement Erreur arrondi Bruit quantification Estimation signal Signal aléatoire Estimation adaptative

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A new grey mapping function and its adaptive algorithm for low-light image enhancement

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MULTIMEDIA TOOLS AND APPLICATIONS 2023年第4期82卷 6071-6096页

作者： He, Lei Long, Wei Liu, Shouxin Li, Yanyan Ding, Wei Sichuan Univ Sch Mech Engn Chengdu Peoples R China

When taking images in low light conditions, images often suffer from low visibility. In addition to affecting the sensory quality of images, this poor quality may also significantly limit the performance of various computer vision systems. Many grey-level mapping enhancement algorithms based on classic mapping functions, such as the gamma mapping function, have been proposed in recent years to improve the visual quality of low-light images. However, the classic mapping function cannot coordinate the greyscale distribution of the bright and dark areas of the image well and may easily lead to excessive enhancement. This makes it difficult for the performance of these improved algorithms to be fully utilized. Therefore, this paper proposes a new multiparameter grey mapping method. Unlike the classic mapping function, the new mapping method is based on the enhancement strategy of compressing the bright area and then adjusting the dark area. Thus, the inherent shortcomings of the classic mapping function are fundamentally overcome. The new mapping method can not only directly control the compression of the grey space in the bright area of the image through parameters, but it can also adjust the greyscale distribution of dark areas without changing the greyscale value of the pixels in the bright area. Finally, this paper also designs an adaptive enhancement algorithm with the new mapping method as the core to verify its effectiveness and flexibility. Experimental results showed that the adaptive algorithm had excellent performance in colour rendering, brightness enhancement and noise suppression. It was also obviously better than the current similar algorithms in visual quality and quantitative tests.

关键词： Brightness enhancement Contrast enhancement adaptive algorithm Low-light image Mapping function Noise suppression

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Activated-carbon electric-double-layer capacitors: electrochemical characterization and adaptive algorithm implementation

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JOURNAL OF POWER SOURCES 2005年第2期141卷 369-385页

作者： Verbrugge, MW Liu, P Soukiazian, S GM Corp Mat & Proc Lab R&D Ctr Warren MI 48090 USA HRL Labs LLC Malibu CA 90265 USA

An activated-carbon electric-double-layer capacitor is characterized and an adaptive algorithm is derived and implemented that is commensurate with potential traction applications of these energy storage devices. The electrochemical characterization relies on a simplified equivalent circuit interpretation extracted from a more-complete mathematical representation of the capacitor system. In addition to the high power capability and potentially low costs of this class of capacitors, we clarify the substantial invariance of the device performance with respect to temperature, a distinct advantage over battery systems. The robustness of the equivalent circuit in terms of capturing the salient features of the experimental data over the temperature and voltage range of interest enables the formulation of a model-reference adaptive algorithm. The algorithm developed and implemented in this work is fully recursive in that the only variables required for on-line regression are those of the previous time step and the current time step. Successful comparisons of the algorithm's adapted state of charge and power predictions provide an initial validation of the algorithm. (c) 2004 Elsevier B.V.. All rights reserved.

关键词： capacitor state of charge activated carbon adaptive algorithm control power capability

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Equivalent analysis of orthogonal viscoelastic jointed rock via an adaptive algorithm in time domain

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FINITE ELEMENTS IN ANALYSIS AND DESIGN 2010年第10期46卷 875-888页

作者： Ren, Yi Yang, Haitian Dalian Univ Technol Dept Engn Mech State Key Lab Struct Anal Ind Equipment Dalian 116024 Peoples R China

This paper presents a recursive equivalent constitutive model that is nested in an FE (finite element) based recursive adaptive process to estimate equivalent behaviors of orthogonal viscoelastic jointed rock. An adaptive algorithm in the time domain and a simple equivalence assumption are combined to convert an inhomogeneous time dependent problem into a series of recursive homogeneous time independent problems, which can be solved either by finite element method (FEM) or other well developed numerical schemes. Ten equivalent analysis based numerical solutions are compared with the FE-based heterogeneous solutions via ANSYS. In the viewpoint of balance between computing accuracy and cost, the results achieved by the proposed approach are fairly good. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.

关键词： Jointed rock Viscoelasticity Equivalent analysis Time-domain adaptive algorithm

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A FAST EXACT FTF adaptive algorithm

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ANNALES DES TELECOMMUNICATIONS-ANNALS OF TELECOMMUNICATIONS 1994年第7-8期49卷 398-406页

作者： REN, ZY HARTMANN, I SCHUTZE, H DEUTSCH BUNDESPOST TELEKOM CTR RES & TECHNOLD-12103 BERLINGERMANY

In this paper we present a new method for the efficient implementation of the fast transversal filter (FTF) algorithm. Reduction of the arithmetic complexity is obtained by making use of the redundancy in the successive computations of the forward prediction error and the filtering error in the joint process. The resulting algorithm is exactly equivalent to the original FTF algorithm, hence retaining the same theoretical convergence characteristics and offering the least squares (LS) estimate at each recursion step without delay. Furthermore, the algorithm can be numerically stabilized by using a simple and effective stabilization measure which needs only one additional multiplication per recursion step. The equivalence of the proposed algorithm to the original FTF algorithm is demonstrated by simulations of an acoustic room impulse response identification.

关键词： TRANSVERSE FILTER adaptive algorithm FAST algorithm algorithm COMPLEXITY ESTIMATION ERROR STABILIZATION ECHO CANCELER

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A Context-aware adaptive algorithm for ambient intelligence DASH at mobile edge computing

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JOURNAL OF AMBIENT INTELLIGENCE AND HUMANIZED COMPUTING 2020年第4期11卷 1377-1385页

作者： Kim, Jinsul Won, Yonggwan Yoon, Changwoo Kim, Jin-Young Park, Sangho Ryou, JaeCheol Ma, Linh Van Chonnam Natl Univ Sch Elect & Comp Engn 77 Yongbong Ro Gwangju 500757 South Korea Elect & Telecommun Res Inst 218 Gajeong Ro Daejeon 34129 South Korea JiranSoft Researh Ctr 87 Daehak Ro Daejeon South Korea Chungnam Natl Univ Dept Comp Engn 87 Daehak Ro Daejeon South Korea

adaptive streaming has recently emerged as a technology enabling high-quality streaming at various bitrates. One of the video streaming challenges remains in research topic nowadays that is choosing optimal segment base on network characteristics and streaming devices, such as network bandwidth, latency, the computational capacities of devices. Researchers have proposed many algorithms to overcome such issues within their predefined conditions. However, those proposed methods do not perform efficiently in the heterogeneous network today. Consequently, in this article, we present research on a context-aware adaptive algorithm for ambient intelligence dynamic adaptive employing mobile edge computing (MEC). Specifically, we apply deep learning in the adaptive algorithm which is installed at the MEC to assist clients in choosing the optimal streaming segments as well as reduce network latency. Furthermore, we apply the multilayer perceptron classifier with data obtained from various experiments of adaptive streaming algorithms then combine them in a general algorithm. In the analysis, we use network simulator NS3 as a tool to carry out the verification of our proposed method. As a result, the proposed research reduces network latency as well as improve quality streaming compared to existing approaches.

关键词： adaptive streaming DASH Deep learning Mobile edge computing adaptive algorithm

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A POSTERIORI ERROR ESTIMATION AND adaptive algorithm FOR ATOMISTIC/CONTINUUM COUPLING IN TWO DIMENSIONS

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SIAM JOURNAL ON SCIENTIFIC COMPUTING 2018年第4期40卷 A2087-A2119页

作者： Wang, Hao Liao, Mingjie Lin, Ping Zhang, Lei Sichuan Univ Coll Math 24 South Sect OneYihuan Rd Chengdu 610065 Sichuan Peoples R China Univ Sci & Technol Beijing Dept Appl Math & Mech 30 Xueyuan Rd Beijing 100083 Peoples R China Univ Dundee Dept Math Dundee DD1 4HN Scotland Shanghai Jiao Tong Univ Sch Math Sci Inst Nat Sci 800 Dongchuan Rd Shanghai 200240 Peoples R China Shanghai Jiao Tong Univ Key Lab Sci & Engn Comp MOE LSC Minist Educ 800 Dongchuan Rd Shanghai 200240 Peoples R China

Atomistic/continuum coupling methods aim to achieve optimal balance between accuracy and efficiency. Adaptivity is the key for the efficient implementation of such methods. In this paper, we carry out a rigorous a posteriori analysis of the residual, the stability constant, and the error bound for a consistent atomistic/continuum coupling method in two dimensions. We design and implement the corresponding adaptive mesh refinement algorithm, and the convergence rate with respect to degrees of freedom is optimal compared with a priori error estimates.

关键词： atomistic models coarse graining atomistic-to-continuum coupling adaptive algorithm a posteriori error estimate

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An adaptive algorithm based on the shifted inverse iteration for the Steklov eigenvalue problem

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APPLIED NUMERICAL MATHEMATICS 2016年 105卷 64-81页

作者： Bi, Hai Li, Hao Yang, Yidu Guizhou Normal Univ Sch Math & Comp Sci Guiyang 550001 Peoples R China

This paper proposes and analyzes an a posteriori error estimator for the finite element multi-scale discretization approximation of the Steklov eigenvalue problem. Based on the a posteriori error estimates, an adaptive algorithm of shifted inverse iteration type is designed. Finally, numerical experiments comparing the performances of three kinds of different adaptive algorithms are provided, which illustrate the efficiency of the adaptive algorithm proposed here. (C) 2016 IMACS. Published by Elsevier B.V. All rights reserved.

关键词： Steklov eigenvalue problem Finite element Multi-scale discretization adaptive algorithm A posteriori error estimate

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An adaptive algorithm for fast frequency response computation of planar microwave structures

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IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES 2004年第3期52卷 920-926页

作者： Prakash, VVS Yeo, J Mittra, R Sigrity Inc Santa Clara CA 95051 USA Penn State Univ Electromagnet Commun Lab University Pk PA 16802 USA Penn State Univ Dept Elect Engn University Pk PA 16802 USA

A fast and efficient adaptive algorithm for computing the response of microwave circuits over a wide frequency band is introduced in this paper. The algorithm uses a binary-tree structure for sweeping the frequency and constructs the currents induced on the circuit by using characteristic basis functions, thus obviating the need to repeatedly solve a large method of moments matrix system at each frequency point. The implementation of the proposed algorithm is quite simple and can be readily integrated into existing electromagnetic simulation software modules. Numerical results are presented for two test cases demonstrating the accuracy and computational efficiency of the proposed technique.

关键词： adaptive algorithm binary tree characteristic basis frequency response method of moments (MoM)

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QUANTIZATION EFFECTS IN THE COMPLEX LMS adaptive algorithm - LINEARIZATION USING DITHER-THEORY

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS 1987年第7期34卷 848-854页

作者： SHERWOOD, DT BERSHAD, NJ NORTHRUP CORP ANAHEIMCA

This paper describes the use of dither to linearize the gradient quantizer in a digitally implemented LMS adaptive algorithm. When the LMS algorithm is implemented in a fixed-point digital processor, a choice must be made between rounding the gradient estimate before addition to the contents of the weight accumulator, or rounding the weight at the accumulator output and operating a double-precision accumulator. Because of hardware constraints, the former approach is often elected. However, when the weight accumulator input is quantized, care must be exercised to prevent the algorithm from stalling. To overcome this difficulty, a sequence of random vectors, called "dither," is used to "linearize" the gradient quantizer. A difference equation for the weight covariance matrix is derived, and a solution for transient mean-square error is obtained that includes both the effects of dither and quantization noise.

关键词： Quantization Least squares approximation adaptive algorithm Vectors Hardware Digital filters Steady-state Difference equations Covariance matrix

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