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Research on heterogeneous fiber grating spectrum separation based on transfer matrix and adaptive algorithm

OPTICAL ENGINEERING 2019年第9期58卷

作者： Jiang, Shanchao Lin, Ping Chen, Yongming Tian, Changbin Yancheng Inst Technol Sch Elect Engn Yancheng Peoples R China Shandong Univ Sch Control Sci & Engn Jinan Shandong Peoples R China

To save the cost of the fiber grating sensing technology demodulation equipment and broaden the range of its detection application, one heterogeneous fiber grating spectrum separation (HFGPS) method based on transfer matrix and the adaptive algorithm is proposed. First, a theoretical mode of the HFGPS method is introduced. Second, simulation experiment on linearly chirped fiber Bragg grating (LCFBG) and fiber Bragg grating (FBG) is carried out to obtain the separation effect. After simulation experiment data analyses, relative errors between the separated spectrum signal and the heterogeneous original signal are no >5.29%, which occurs at spectrum fringe region of FBG and LCFBG, and the separation algorithm can achieve single wavelength or multiwavelength mixing heterogeneous spectrum efficient separation with high precision. Lastly, the temperature calibration experiment is carried out on FBG temperature sensor and LCFBG to further verify the effect of the HFGPS method. After the temperature experiment data analyses, the result shows that sensitivity relative error of FBG between original and heterogeneous separated is 0.4%, and the HFGPS method can achieve heterogeneous spectrum efficient separation and has small influence on the detection performance of the FBG sensor. All these experiment data confirm that the HFGPS method can achieve effective heterogeneous spectrum separation with high precision and has certain practical application value. (C) 2019 Society of Photo-Optical Instrumentation Engineers (SPIE)

关键词： heterogeneous spectrum separation transfer matrix adaptive algorithm fiber Bragg grating linearly chirped fiber Bragg grating

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A plasticity based model and an adaptive algorithm for finite element analysis of reinforced concrete panels

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INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING 2002年第11期53卷 2445-2462页

作者： Pravida, J Wunderlich, W Tech Univ Munich Lehrstuhl Stat D-80290 Munich Germany

This paper deals with an adaptive finite element procedure for the analysis of plain and reinforced concrete panels in a state of plane stress. Therefore, we will present a plasticity based model for plain concrete which captures the two failure modes of concrete within one formulation. In spite of a simple formulation the model is capable to describe the different mechanisms for tensile failure as well as for compression fracture. To restrict the time discretization error and the spatial discretization error to certain tolerances, the constitutive model is embedded in an adaptive algorithm which controls the size of the incremental load steps and leads to a hierarchical mesh refinement if necessary. The application of the model will be shown by various numerical examples. Copyright (C) 2002 John Wiley Sons, Ltd.

关键词： plasticity adaptive algorithm state of plane stress reinforced concrete

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Balanced parallel triangle enumeration with an adaptive algorithm

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DISTRIBUTED AND PARALLEL DATABASES 2024年第1期42卷 103-141页

作者： Farouzi, Abir Zhou, Xiantian Bellatreche, Ladjel Malki, Mimoun Ordonez, Carlos ISAE ENSMA Poitiers France Univ Houston Houston TX USA Ecole Super Informat Sidi Bel Abbes Algeria

Triangle enumeration is a foundation brick for solving harder graph problems related to social networks, the Internet and transportation, to name a few applications. This problem is well studied in the theory literature, but remains an open problem with big data. In this paper, we defend the idea of solving triangle enumeration with SQL queries evaluating the steps of a new adaptive algorithm with linear speedup. Such SQL approach provides scalability beyond RAM limits, automatic parallel processing and more importantly: linear speedup as more machines are added. We present theory results and experimental validation showing our solution works well with large graphs analyzed on a parallel cluster with many machines, producing a balanced workload even with highly skewed degree vertices. We consider two types of distributed systems: (1) a parallel DBMS that evaluates SQL queries, and (2) a parallel HPC cluster calling the MPI library (called via Python). Extensive benchmark experiments with large graphs show our SQL solution offers many advantages over MPI and competing graph analytic systems.

关键词： Triangle enumeration Triangle counting Graph analytics adaptive algorithm Intelligent data distribution

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An adaptive algorithm for Steklov eigenvalues of the Lamé operator in linear elasticity

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COMPUTATIONAL & APPLIED MATHEMATICS 2024年第4期43卷 1-25页

作者： Li, Hao Zhang, Yu Guizhou Normal Univ Sch Math Sci Huayan Rd Guiyang 550025 Guizhou Peoples R China Guizhou Univ Finance & Econ Sch Math & Stat Huayan Rd Guiyang 550025 Guizhou Peoples R China

The Steklov eigenvalues of the Lam & eacute;operator arise from the analysis of surface waves and vibration modes in a linearly elastic structure. In this paper, based on the Lagrange conforming finite element method, we propose and analyze an a posteriori error indicator of the residual type for the Steklov eigenvalue problem of the Lam & eacute;operator in linear elasticity. The a posteriori error indicator is computed locally from the approximate eigenpair. We prove the reliability and the efficiency of the error indicator for eigenfunctions as well as the reliability of the error indicator for eigenvalues. Finally, we present numerical experiments to validate our theoretical analysis.

关键词： adaptive algorithm Steklov eigenvalue Lam & eacute operator Linear elasticity

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Rapid identification of a sparse impulse response using an adaptive algorithm in the Haar domain

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 2003年第3期51卷 628-638页

作者： Ho, KC Blunt, SD Univ Missouri Dept Elect & Comp Engn Columbia MO 65211 USA

This paper proposes a fast convergence adaptive algorithm for identifying a sparse impulse response that is rich in spectral content A sparse impulse response is referred here as a discrete time impulse response that has a large number of zero or near zero coefficients. The basic idea for rapid identification is to automatically determine the locations of the nonzero impulse response coefficients for their adaptation and eliminate the unnecessary adaptation of zero coefficients The proposed method, which is called the Haar-Basis algorithm, employs a transform approach by modeling the sparse impulse response in the Haar domain. The Haar transform has many basis sets and each of them contains basis vectors that span the entire time domain range. This special nature of the Haar transform allows for the selection of one small subset of adaptive filter coefficients whose basis vectors span the entire range of the impulse response These coefficients are adapted at the beginning and are then used subsequently to identify, from the hierarchical structure of the Haar transform, the rest of the filter coefficients that must be adapted to correctly model the unknown sparse impulse response. The consequence is avoiding adaptation of many zero coefficients, leading to a dramatic improvement in either convergence speed or steady state excess mean-square error (EMSE), while requiring no a priori knowledge such as the number of nonzero coefficients in the unknown sparse impulse response. The proposed algorithm has been tested with a variety of unknown sparse systems using both white noise input and colored input whose spectrum closely resembles that of speech. Simulation results show that the new approach provides promising results.

关键词： adaptive algorithm Haar transform sparse impulse response system identification

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A High-Order p-adaptive algorithm for Large-Eddy Simulation Based on a Discontinuous Galerkin Method

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INTERNATIONAL JOURNAL OF COMPUTATIONAL FLUID DYNAMICS 2024年第2-3期38卷 102-134页

作者： Naddei, Fabio Plata, Marta de la Llave Inst Polytech Paris DAAA ONERA Chatillon France Univ Toulouse DMPE ONERA Toulouse France

The aim of this paper is to present and analyse a static p-adaptation algorithm based on a modal high-order discontinuous Galerkin method. To this end, we first define appropriate error estimation strategies that provide information on the necessary time-independent local resolution quality. Two error indicators are employed, the Small-Scale Energy Density (SSED) indicator proposed in Naddei (2019) and the novel Small-Scale Lifted (SSL) indicator developed in this work. Based on the SSED estimator, three different strategies are considered to extend these indicators to perform static p-adaptive simulations of unsteady flow problems. The first approach consists in applying the SSED estimator to the time-averaged solution (SSED-A). The second and third approaches consist in evaluating the temporal $ L<^>2 $ L2 and $ L<^>\infty $ L infinity-norms of the indicator computed from the instantaneous solution, called respectively $ L<^>2 $ L2-SSED and $ L<^>\infty $ L infinity-SSED. These strategies are compared by performing simulations of the periodic laminar flow past a cylinder at $ {\rm Re}=100 $ Re=100 and Mach = 0.1, and of the turbulent flow over periodic hills at $ {\rm Re}=2\,800 $ Re=2800. The outcome from these computations shows that the best performance is achieved when the $ L<^>\infty $ L infinity-SSED indicator is used. Finally, the developed adaptation algorithm is applied to the LES of the transitional flow past a NACA0012 airfoil at $ {\rm Re}=50\,000 $ Re=50000 and $ \alpha =5<^>\circ $ alpha=5 degrees using the $ L<^>\infty $ L infinity-SSED and the $ L<^>\infty $ L infinity-SSL indicators. It is shown that the use of the SSL indicator provides improved results as compared to the SSED indicator. The results presented in this paper demonstrate that the use of p-adaption improves the quality of under-resolved turbulent flow simulations for a similar computational cost as compared to p-uniform simulations.

关键词： High-order discontinuous Galerkin adaptive algorithm error estimation Large-Eddy simulation

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A Temporally-Piecewise adaptive algorithm to Solve Transient Convection-Diffusion Heat Transfer Problems

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CMES-COMPUTER MODELING IN ENGINEERING & SCIENCES 2011年第2期74卷 139-159页

作者： Zhao, Xiao Yang, Haitian Gao, Qiang Dalian Univ Technol State Key Lab Struct Anal Ind Equipment Dept Engn Mech Dalian 116024 Peoples R China

A piecewised adaptive algorithm in the time domain is presented to solve the transient convection-diffusion heat transfer problem. By expanding all variables at a time interval, an initial and boundary value problem is decoupled into a series of recursive boundary value problems which can be solved by FEM or other well developed numerical schemes to deal with boundary value problems. A steady computing accuracy can be adaptively maintained via the power increase of the expansion, particularly when the step size varies in the whole computing process. Additionally for the nonlinear cases, there is no requirement of iteration and additional assumption for the proposed algorithm. Three numerical examples are provided to verify the presented algorithm,and satisfactory results have been achieved.

关键词： convection-diffusion heat transfer adaptive algorithm time domain FEM

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An optimal adaptive algorithm for the approximation of concave functions

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MATHEMATICAL PROGRAMMING 2006年第3期107卷 357-366页

作者： Guérin, J Marcotte, P Savard, G Ecole Polytech Montreal Dept Math & Genie Ind Montreal PQ H3C 3A7 Canada Univ Montreal CRT Montreal PQ H3C 3J7 Canada Univ Montreal DIRO Montreal PQ H3C 3J7 Canada Ecole Polytech Montreal GERAD Montreal PQ H3C 3A7 Canada

Motivated by the study of parametric convex programs, we consider approximation of concave functions by piecewise affine functions. Using dynamic programming, we derive a procedure for selecting the knots at which an oracle provides the function value and one supergradient. The procedure is adaptive in that the choice of a knot is dependent on the choice of the previous knots. It is also optimal in that the approximation error, in the integral sense, is minimized in the worst case.

关键词： dynamic programming approximation adaptive algorithm

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A SIMPLE HARD-LIMITED adaptive algorithm FOR BLIND EQUALIZATION

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-ANALOG AND DIGITAL SIGNAL PROCESSING 1992年第7期39卷 482-487页

作者： WEERACKODY, V KASSAM, SA LAKER, KR UNIV PENN DEPT ELECT ENGNPHILADELPHIAPA 19104

Blind equalization is a technique for adaptive equalization of a communication channel without the aid of the usual training sequence. In this paper we propose a new algorithm for adaptive blind equalization. We interpret this algorithm as a sign version of a widely referenced algorithm for blind equalization and demonstrate by way of simulations the comparable performance of this new sign algorithm to its unsigned version. We also propose a simple variable step-size scheme to accelerate the convergence process. Simulation results are presented to demonstrate the significant improvements in the convergence rates that are obtained using this variable step-size scheme.

关键词： adaptive algorithm adaptive equalizers Blind equalizers Signal processing algorithms Very large scale integration Digital arithmetic Circuits and systems Hardware Testing Digital signal processing

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A new linear prediction filter based adaptive algorithm for IIR ADF using allpass and minimum phase system

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IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 1998年第1期E81A卷 123-130页

作者： Okello, J Itoh, Y Fukui, Y Kobayashi, M Tottori Univ Fac Engn Tottori 680 Japan Ibaraki Univ Fac Engn Hitachi Ibaraki 316 Japan

An adaptive infinite impulse response (IIR) filter implemented using an allpass and a minimum phase system has an advantage of its poles converging to the poles of the unknown system when the input is a white signal. However, when the input signal is colored, convergence speed deteriorates considerably, even to the point of lack of convergence for certain colored signals. Furthermore with a colored input signal, there is no guarantee that the poles of the adaptive digital filter (ADF) will converge to the poles of the unknown system. In this paper we propose a method which uses a linear predictor filter to whiten the input signal so as to improve the convergence characteristic. Computer simulation results confirm the increase in convergence speed and the convergence of the poles of the ADF to the poles of the unknown system even when the input is a colored signal.

关键词： adaptive IIR filter system identification adaptive algorithm linear predictor filter signal decorrelation

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