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Artículos de revistas sobre el tema "Wavelets and fast transform eavelet"

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Publicado: 4 de junio de 2021
Última modificación: 15 de febrero de 2022

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1

Stolarek, J. "Adaptive synthesis of a wavelet transform using fast neural network." Bulletin of the Polish Academy of Sciences: Technical Sciences 59, no. 1 (2011): 9–13. http://dx.doi.org/10.2478/v10175-011-0002-5.

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Adaptive synthesis of a wavelet transform using fast neural network This paper introduces a new method for an adaptive synthesis of a wavelet transform using a fast neural network with a topology based on the lattice structure. The lattice structure and the orthogonal lattice structure are presented and their properties are discussed. A novel method for unsupervised training of the neural network is introduced. The proposed approach is tested by synthesizing new wavelets with an expected energy distribution between low- and high-pass filters. Energy compaction of the proposed method and Daubec
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2

Wu, Jiasong, Fuzhi Wu, Qihan Yang, et al. "Fractional Spectral Graph Wavelets and Their Applications." Mathematical Problems in Engineering 2020 (November 6, 2020): 1–18. http://dx.doi.org/10.1155/2020/2568179.

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One of the key challenges in the area of signal processing on graphs is to design transforms and dictionary methods to identify and exploit structure in signals on weighted graphs. In this paper, we first generalize graph Fourier transform (GFT) to spectral graph fractional Fourier transform (SGFRFT), which is then used to define a novel transform named spectral graph fractional wavelet transform (SGFRWT), which is a generalized and extended version of spectral graph wavelet transform (SGWT). A fast algorithm for SGFRWT is also derived and implemented based on Fourier series approximation. Som
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3

Li, Yaoguo, and Douglas W. Oldenburg. "Rapid construction of equivalent sources using wavelets." GEOPHYSICS 75, no. 3 (2010): L51—L59. http://dx.doi.org/10.1190/1.3378764.

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We have developed a fast algorithm for generating an equivalent source by using fast wavelet transforms based on orthonormal, compactly supported wavelets. We apply a 2D wavelet transform to each row and column of the coefficient matrix and subsequently threshold the transformed matrix to generate a sparse representation in the wavelet domain. The algorithm then uses this sparse matrix to construct the the equivalent source directly in the wavelet domain. Performing an inverse wavelet transform then yields the equivalent source in the space domain. Using upward continuation of total-field magn
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4

Toda, Hiroshi, Zhong Zhang, and Takashi Imamura. "Practical design of perfect-translation-invariant real-valued discrete wavelet transform." International Journal of Wavelets, Multiresolution and Information Processing 12, no. 04 (2014): 1460005. http://dx.doi.org/10.1142/s0219691314600054.

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The real-valued tight wavelet frame having perfect translation invariance (PTI) has already proposed. However, due to the irrational-number distances between wavelets, its calculation amount is very large. In this paper, based on the real-valued tight wavelet frame, a practical design of a real-valued discrete wavelet transform (DWT) having PTI is proposed. In this transform, all the distances between wavelets are multiples of 1/4, and its transform and inverse transform are calculated fast by decomposition and reconstruction algorithms at the sacrifice of a tight wavelet frame. However, the r
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5

Cheriet, Leyla, Salah Chenikher, and Karima Boukari. "Fast motion estimation algorithm based on geometric wavelet transform." International Journal of Wavelets, Multiresolution and Information Processing 17, no. 04 (2019): 1950018. http://dx.doi.org/10.1142/s0219691319500188.

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Motion estimation is a means, which consists in studying the displacement of objects in a video sequence, seeking the correlation between two successive frames, to predict the change in the contents position. Motion estimation is becoming a progressively significant requirement in a variety of applications such as medicine, robotics and video compression. In recent years, wavelets are effective tools for motion estimation, but the DWT (Discrete Wavelet Transform) will suffer from problems like translation sensitivity, poor directionality and absence of phase information. These three disadvanta
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6

Irfan, Nagma, and A. H. Siddiqi. "A Wavelet Algorithm for Fourier-Bessel Transform Arising in Optics." International Journal of Engineering Mathematics 2015 (August 31, 2015): 1–9. http://dx.doi.org/10.1155/2015/789675.

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The aim of the paper is to propose an efficient and stable algorithm that is quite accurate and fast for numerical evaluation of the Fourier-Bessel transform of order ν, ν>-1, using wavelets. The philosophy behind the proposed algorithm is to replace the part tf(t) of the integral by its wavelet decomposition obtained by using CAS wavelets thus representing Fν(p) as a Fourier-Bessel series with coefficients depending strongly on the input function tf(t). The wavelet method indicates that the approach is easy to implement and thus computationally very attractive.
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7

Stolarek, Jan. "Improving energy compaction of a wavelet transform using genetic algorithm and fast neural network." Archives of Control Sciences 20, no. 4 (2010): 417–33. http://dx.doi.org/10.2478/v10170-010-0024-5.

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Improving energy compaction of a wavelet transform using genetic algorithm and fast neural networkIn this paper a new method for adaptive synthesis of a smooth orthogonal wavelet, using fast neural network and genetic algorithm, is introduced. Orthogonal lattice structure is presented. A new method of supervised training of fast neural network is introduced to synthesize a wavelet with desired energy distribution between output signals from low-pass and high-pass filters on subsequent levels of a Discrete Wavelet Transform. Genetic algorithm is proposed as a global optimization method for defi
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8

Abeyratne, M. K., W. Freeden, and C. Mayer. "Multiscale deformation analysis by Cauchy-Navier wavelets." Journal of Applied Mathematics 2003, no. 12 (2003): 605–45. http://dx.doi.org/10.1155/s1110757x03206033.

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A geoscientifically relevant wavelet approach is established for the classical (inner) displacement problem corresponding to a regular surface (such as sphere, ellipsoid, and actual earth surface). Basic tools are the limit and jump relations of (linear) elastostatics. Scaling functions and wavelets are formulated within the framework of the vectorial Cauchy-Navier equation. Based on appropriate numerical integration rules, a pyramid scheme is developed providing fast wavelet transform (FWT). Finally, multiscale deformation analysis is investigated numerically for the case of a spherical bound
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9

Grohs, Philipp, Željko Kereta, and Uwe Wiesmann. "A shearlet-based fast thresholded Landweber algorithm for deconvolution." International Journal of Wavelets, Multiresolution and Information Processing 14, no. 05 (2016): 1650032. http://dx.doi.org/10.1142/s0219691316500326.

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Image deconvolution is an important problem, which has seen plenty of progress in the last decades. Due to its ill-posedness, a common approach is to formulate the reconstruction as an optimization problem[Formula: see text] regularized by an additional sparsity-enforcing term. This term is often modeled as an [Formula: see text] norm measured in the domain of a suitable signal transform. The resulting optimization problem can be solved by an iterative approach via Landweber iterations with soft thresholding of the transform coefficients. Previous approaches focused on thresholding in the wave
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10

Goyal, Er Neha. "Implementation of Image Compression using fast Wavelet Transform using HAAR and Daubechies Wavelets." IOSR Journal of Engineering 02, no. 11 (2012): 18–24. http://dx.doi.org/10.9790/3021-021121824.

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11

AWREJCEWICZ, J., A. V. KRYSKO, I. E. KUTEPOV, N. A. ZAGNIBORODA, M. V. ZHIGALOV, and V. A. KRYSKO. "ANALYSIS OF CHAOTIC VIBRATIONS OF FLEXIBLE PLATES USING FAST FOURIER TRANSFORMS AND WAVELETS." International Journal of Structural Stability and Dynamics 13, no. 07 (2013): 1340005. http://dx.doi.org/10.1142/s0219455413400051.

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In this paper chaotic vibrations of flexible plates of infinite length are studied. The Kirchhoff–Love hypotheses are used to derive the nondimensional partial differential equations governing the plate dynamics. The finite difference method (FDM) and finite element method (FEM) are applied to validate the numerical results. The numerical analysis includes both standard (time histories, fast Fourier Transform, phase portraits, Poincaré sections, Lyapunov exponents) as well as wavelet-based approaches. The latter one includes the so called Gauss 1, Gauss 8, Mexican Hat and Morlet wavelets. In p
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12

Mennouni, Abdelaziz, Nedjem Eddine Ramdani, and Khaled Zennir. "A new class of fredholm integral equations of the second kind with non symmetric kernel: solving by wavelets method." Boletim da Sociedade Paranaense de Matemática 39, no. 6 (2021): 67–80. http://dx.doi.org/10.5269/bspm.41734.

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In this paper, we present an ecient modication of the wavelets method to solve a new class of Fredholm integral equations of the second kind with non symmetric kernel. This -analytical method based on orthonormal wavelet basis, as a consequence three systems are obtained, a Toeplitz system and two systems with condition number close to 1. Since the preconditioned conjugate gradient normal equation residual (CGNR) and preconditioned conjugate gradient normal equation error (CGNE) methods are applicable, we can solve the systems in O(2n log(n)) operations, by using the fast wavelet transform and
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13

Khoromskij, Boris N., and Sentao Miao. "Superfast Wavelet Transform Using Quantics-TT Approximation. I. Application to Haar Wavelets." Computational Methods in Applied Mathematics 14, no. 4 (2014): 537–53. http://dx.doi.org/10.1515/cmam-2014-0016.

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AbstractWe propose a superfast discrete Haar wavelet transform (SFHWT) as well as its inverse, using the low-rank Quantics-TT (QTT) representation for the Haar transform matrices and input-output vectors. Though the Haar matrix itself does not have a low QTT rank approximation, we show that factor matrices used at each step of the traditional multilevel Haar wavelet transform algorithm have explicit QTT representations of low rank. The SFHWT applies to a vector representing a signal sampled on a uniform grid of size ${N=2^d}$. We develop two algorithms which roughly require square logarithmic
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14

Prosser, R., and R. S. Cant. "The theoretical development of wavelets in reacting flows." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 214, no. 11 (2000): 1363–73. http://dx.doi.org/10.1243/0954406001523335.

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This paper focuses on the simulation of turbulent reacting flows via recent developments in wavelet-based analyses. The unique data compression properties of wavelet methods render them especially attractive for such simulations, in which the length and time-scales of interest originate from both physical and chemical processes and may span several orders of magnitude. The particular difficulties encountered when representing reacting flow problems on non-periodic domains, and how these difficulties have led to the adoption of a biorthogonal wavelet framework, are discussed. This leads to cons
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15

Kaplun, Dmitry, Alexander Voznesensky, Sergei Romanov, Valery Andreev, and Denis Butusov. "Classification of Hydroacoustic Signals Based on Harmonic Wavelets and a Deep Learning Artificial Intelligence System." Applied Sciences 10, no. 9 (2020): 3097. http://dx.doi.org/10.3390/app10093097.

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This paper considers two approaches to hydroacoustic signal classification, taking the sounds made by whales as an example: a method based on harmonic wavelets and a technique involving deep learning neural networks. The study deals with the classification of hydroacoustic signals using coefficients of the harmonic wavelet transform (fast computation), short-time Fourier transform (spectrogram) and Fourier transform using a kNN-algorithm. Classification quality metrics (precision, recall and accuracy) are given for different signal-to-noise ratios. ROC curves were also obtained. The use of the
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16

Chancey, V. C., G. T. Flowers, and C. L. Howard. "A Harmonic Wavelets Approach for Extracting Transient Patterns From Measured Rotor Vibration Data." Journal of Engineering for Gas Turbines and Power 125, no. 1 (2002): 81–89. http://dx.doi.org/10.1115/1.1520156.

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Vibration analysis is a powerful diagnostic tool for rotating machinery problems. Traditional approaches to vibration signature analysis have focused on the Fourier transform, which tends to average out transient effects. Recent work in the area of wavelets has allowed for the characterization of signals in frequency and in time, which, if properly interpreted, can provide substantial insight, particularly with regard to transient behaviors. There are many different types of wavelets, but the harmonic wavelet was developed specifically for vibration analysis. It uses an algorithm based upon th
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17

HAWKINS, STUART C., KE CHEN, and PAUL J. HARRIS. "AN OPERATOR SPLITTING PRECONDITIONER FOR MATRICES ARISING FROM A WAVELET BOUNDARY ELEMENT METHOD FOR THE HELMHOLTZ EQUATION." International Journal of Wavelets, Multiresolution and Information Processing 03, no. 04 (2005): 601–20. http://dx.doi.org/10.1142/s0219691305001044.

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An operator splitting type preconditioner is presented for fast solution of linear systems obtained by Galerkin discretization of the Burton and Miller formulation for the Helmholtz equation. Our approach differs from usual boundary element treatments of the three-dimensional scattering problem because we use a basis of biorthogonal wavelets. Such wavelets result in a sparse linear system and that facilitates preconditioning and makes matrix vector products cheap to form. In this Part I of our work, we implement a biorthogonal wavelet transform on a closed surface in three dimensions. Numerica
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18

Santos, Diogo, Tiago Abreu, Paulo A. Silva, and Paulo Baptista. "Estimation of Coastal Bathymetry Using Wavelets." Journal of Marine Science and Engineering 8, no. 10 (2020): 772. http://dx.doi.org/10.3390/jmse8100772.

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When waves propagate in coastal areas at depths lower than one half the wavelength, they exhibit a different signature at the sea surface and the observed wavelength pattern enables inferring bathymetries. Commonly, a spectral analysis using the fast Fourier transform (FFT) is employed to derive wavelength and wave direction of swell waves, in nearshore regions. Nevertheless, it is recognized that this method presents limitations, particularly regarding depth inversion limits that do not allow obtaining bathymetric data close to the shoreline. This work explores a wavelet spectral analysis to
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19

CHEN, WENJIE, XU YANG, and ZHAOAN WANG. "AN APPLICATION OF COMPLEX WAVELETS FOR HIGH FREQUENCY SWITCHING NOISE DETECTION." Journal of Circuits, Systems and Computers 18, no. 01 (2009): 97–102. http://dx.doi.org/10.1142/s0218126609004958.

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Switching signal is always composed of a series of fast voltage and current transient impulsive waves, which are created during turn-on and turn-off operation of the switching elements. This paper presents a scalogram and phase spectrum analyzing approach for the high-frequency switching noise detection. A complex Gaussian wavelet is used to extract the oscillation feature of the noise signal. The proposed scheme is more suitable in discriminating the type of switching noise than conventional wavelet transform approaches. Simulation results show the effectiveness and advantages of the method.
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20

Quiroga, R. Quian, Z. Nadasdy, and Y. Ben-Shaul. "Unsupervised Spike Detection and Sorting with Wavelets and Superparamagnetic Clustering." Neural Computation 16, no. 8 (2004): 1661–87. http://dx.doi.org/10.1162/089976604774201631.

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This study introduces a new method for detecting and sorting spikes from multiunit recordings. The method combines the wave let transform, which localizes distinctive spike features, with super paramagnetic clustering, which allows automatic classification of the data without assumptions such as low variance or gaussian distributions. Moreover, an improved method for setting amplitude thresholds for spike detection is proposed. We describe several criteria for implementation that render the algorithm unsupervised and fast. The algorithm is compared to other conventional methods using several s
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21

Knowles, G. "Hardware Architectures for the Orthogonal and Biorthogonal Wavelet Transform." VLSI Design 15, no. 2 (2002): 499–506. http://dx.doi.org/10.1080/1065514021000012110.

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In this note, optimal hardware architectures for the orthogonal and biorthogonal wavelet transforms are presented. The approach used here is not the standard lifting method, but takes advantage of the symmetries inherent in the coefficients of the transforms and the decimation/interpolation operators. The design is based on a highly optimized datapath, which seamlessly integrates both orthogonal and biorthogonal transforms, data extension at the edges and the forward and inverse transforms. The datapath design could be further optimized for speed or low power. The datapath is controlled by a s
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22

Irfan, Nagma, and A. H. Siddiqi. "An Application of Wavelet Technique in Numerical Evaluation of Hankel Transforms." International Journal of Nonlinear Sciences and Numerical Simulation 16, no. 6 (2015): 293–99. http://dx.doi.org/10.1515/ijnsns-2015-0031.

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AbstractThis paper endeavors to formulate a stable and fast algorithm for the first time that is quite accurate and fast for numerical evaluation of the Hankel transform using wavelets which are usually difficult to solve analytically so it is required to obtain the approximate solution. So we have proposed an approach depending on separating the integrand $rf(r){J_\nu}(pr)$ into two components, the slowly varying components $rf(r)$ and the rapidly oscillating component ${J_\nu}(pr)$. Then either $rf(r)$ is expanded into wavelet series using wavelets orthonormal basis which are first derived a
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23

Tkacheshak, N. V., and М. І. Horbiichuk. "INVESTIGATION OF EXHAUSTING PHENOMENA OF GAS TURBINE ENGINE ON THE BASIS OF WAVELET ANALYSIS." Scientific Bulletin of Ivano-Frankivsk National Technical University of Oil and Gas, no. 2(45) (November 27, 2018): 24–33. http://dx.doi.org/10.31471/1993-9965-2018-2(45)-24-33.

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The method for research of a gas turbine engine (GTE) surging phenomena based on wavelet analysis was developed. GTE DG-90 was chosen for research. A wavelet decomposition of the air pressure signal was carried out using a high pressure compressor and Dobeski, Symlet, Coffle and Meyer's discrete wavelet. The advantages and disadvantages of filtering properties of these wavelets were graphically represented in the form of amplitude-frequency characteristics. Based on the results obtained, a wavelet transform parameter selection scheme based on the analysis of the frequency response of wavelet f
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24

Nashat, Ahmed A., and N. M. Hussain Hassan. "Automatic segmentation and classification of olive fruits batches based on discrete wavelet transform and visual perceptual texture features." International Journal of Wavelets, Multiresolution and Information Processing 16, no. 01 (2018): 1850003. http://dx.doi.org/10.1142/s0219691318500030.

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The quality of olive fruit and its virgin olive oil is a main concern for consumers and fruit industrial companies. The effectiveness and fast detection of olive’s skin defects is the most decisive factor in determining its quality. It is necessary to design and implement image processing tools for segmentation and correct classification of the different fresh incoming olive batches. In this paper, we propose a new automatic image segmentation algorithm, based on discrete wavelets transform. The aim of the segmentation algorithm is to discriminate between olives and the background with the cha
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25

Hamza Cherif, L., N. Benmessaoud, and S. M. Debbal. "Comparison between analysing wavelets in continuous wavelet transform based on the fast Fourier transform: application to estimate pulmonary arterial hypertension by heart sound." International Journal of Biomedical Engineering and Technology 36, no. 2 (2021): 189. http://dx.doi.org/10.1504/ijbet.2021.10039246.

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Cherif, L. Hamza, N. Benmessaoud, and S. M. Debbal. "Comparison between analysing wavelets in continuous wavelet transform based on the fast Fourier transform: application to estimate pulmonary arterial hypertension by heart sound." International Journal of Biomedical Engineering and Technology 36, no. 2 (2021): 189. http://dx.doi.org/10.1504/ijbet.2021.116099.

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27

Yoon, M. C., and D. H. Chin. "Cutting force monitoring in the endmilling operation for chatter detection." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 219, no. 6 (2005): 455–65. http://dx.doi.org/10.1243/095440505x32292.

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The chatter phenomenon shows the dynamic characteristics of tool vibration in the endmilling process and will change according to the irregular dynamic characteristics of that tool vibration. This chatter produces an adverse effect on tool life, machining integrity, surface quality of the workpiece, and other geometric accuracy. Chatter behaviour in endmilling is a complex, non-linear phenomenon, which is very difficult to detect and diagnose. It is therefore necessary to suggest a new method for analysing chatter mechanics. This paper presents a new method for the detection of chatter in the
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28

Liu, Lei, Jingwen Yan, Di Guo, Yunsong Liu, and Xiaobo Qu. "Undersampled Hyperspectral Image Reconstruction Based on Surfacelet Transform." Journal of Sensors 2015 (2015): 1–11. http://dx.doi.org/10.1155/2015/256391.

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Hyperspectral imaging is a crucial technique for military and environmental monitoring. However, limited equipment hardware resources severely affect the transmission and storage of a huge amount of data for hyperspectral images. This limitation has the potentials to be solved by compressive sensing (CS), which allows reconstructing images from undersampled measurements with low error. Sparsity and incoherence are two essential requirements for CS. In this paper, we introduce surfacelet, a directional multiresolution transform for 3D data, to sparsify the hyperspectral images. Besides, a Gram-
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Panigrahy, Parth Sarathi, and Paramita Chattopadhyay. "Cascaded signal processing approach for motor fault diagnosis." COMPEL - The international journal for computation and mathematics in electrical and electronic engineering 37, no. 6 (2018): 2122–37. http://dx.doi.org/10.1108/compel-11-2017-0476.

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PurposeThe purpose of this paper is to inspect strategic placing of different signal processing techniques like wavelet transform (WT), discrete Hilbert transform (DHT) and fast Fourier transform (FFT) to acquire the qualitative detection of rotor fault in a variable frequency drive-fed induction motor under challenging low slip conditions.Design/methodology/approachThe algorithm is developed using Q2.14 bit format of Xilinx System Generator (XSG)-DSP design tool in MATLAB. The developed algorithm in XSG-MATLAB can be implemented easily in field programmable gate array, as a provision to gener
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30

Romanchak, V. M., and M. A. Hundzina. "Isolation of a periodic component by singular wavelet decomposition." «System analysis and applied information science», no. 3 (September 25, 2020): 4–8. http://dx.doi.org/10.21122/2309-4923-2020-3-4-8.

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In this paper, we propose to use a discrete wavelet transform with a singular wavelet to isolate the periodic component from the signal. Traditionally, it is assumed that the validity condition must be met for a basic wavelet (the average value of the wavelet is zero). For singular wavelets, the validity condition is not met. As a singular wavelet, you can use the Delta-shaped functions, which are involved in the estimates of Parzen-Rosenblatt, Nadaraya-Watson. Using singular value of a wavelet is determined by the discrete wavelet transform. This transformation was studied earlier for the con
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31

Patil, TejasKishor, and Ajeet B. Bhane. "DETECTION OF CRACKS IN SIMPLY SUPPORTED BEAM BY USING VARIOUS TECHNIQUES: A REVIEW." International Journal of Research -GRANTHAALAYAH 3, no. 12 (2015): 129–32. http://dx.doi.org/10.29121/granthaalayah.v3.i12.2015.2897.

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In this review work the crack detection procedure by using vibration and wavelet technique is discussed. Crack converts the linear problem to nonlinear problem and affects the natural frequency. So in this paper we discussed the various methods to find out cracks on beams like destructive testing and non-destructive testing. Wavelet technique is mathematical method alternative to the non-destructive testing like fast fourier transform and is also provides good result compared to other methods. As in this the wavelets are developed and it is solved by various types like mother wavelet technique
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32

Kasanický, I., J. Mandel, and M. Vejmelka. "Spectral diagonal ensemble Kalman filters." Nonlinear Processes in Geophysics 22, no. 4 (2015): 485–97. http://dx.doi.org/10.5194/npg-22-485-2015.

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Abstract. A new type of ensemble Kalman filter is developed, which is based on replacing the sample covariance in the analysis step by its diagonal in a spectral basis. It is proved that this technique improves the approximation of the covariance when the covariance itself is diagonal in the spectral basis, as is the case, e.g., for a second-order stationary random field and the Fourier basis. The method is extended by wavelets to the case when the state variables are random fields which are not spatially homogeneous. Efficient implementations by the fast Fourier transform (FFT) and discrete w
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33

Kasanický, I., J. Mandel, and M. Vejmelka. "Spectral diagonal ensemble Kalman filters." Nonlinear Processes in Geophysics Discussions 2, no. 1 (2015): 115–43. http://dx.doi.org/10.5194/npgd-2-115-2015.

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Abstract. A new type of ensemble Kalman filter is developed, which is based on replacing the sample covariance in the analysis step by its diagonal in a spectral basis. It is proved that this technique improves the aproximation of the covariance when the covariance itself is diagonal in the spectral basis, as is the case, e.g., for a second-order stationary random field and the Fourier basis. The method is extended by wavelets to the case when the state variables are random fields which are not spatially homogeneous. Efficient implementations by the fast Fourier transform (FFT) and discrete wa
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34

Pusta, Dana Liana, Rodica Sobolu, Sanda Andrei, et al. "The Influence of Solar Radiation on the Antioxidant Systems in Blood of Dairy Cows and the Processing of the Data Using Wavelets Transforms." Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Veterinary Medicine 73, no. 2 (2016): 314. http://dx.doi.org/10.15835/buasvmcn-vm:12182.

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The purpose of this paper was to observe if in cattle, exposed to the solar radiation, could be noticed a certain reaction of the organism related to the oxidative stress. The study was made in the period May - August 2014, on a group of 16 Romanian Simmental dairy cows, kept on pasture during the day. The processing of the determined data were made using wavelet transforms (In-Place Fast Haar Wavelets Transform). The results of the experiment shown that when Temperature Humidity Indexes (THI) are higher than 72 (the superior limit for thermal comfort in cattle), the oxidative stress appeared
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35

Hui, K. H., L. M. Hee, M. Salman Leong, and Ahmed M. Abdelrhman. "Vibration Condition Monitoring: Latest Trend and Review." Applied Mechanics and Materials 773-774 (July 2015): 139–43. http://dx.doi.org/10.4028/www.scientific.net/amm.773-774.139.

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Vibration analysis has proven to be the most effective method for machine condition monitoring to date. Various effective signal analysis methods to analyze and extract fault signature that embedded in the raw vibration signals have been introduced in the past few decades such as fast Fourier transform (FFT), short time Fourier transform (STFT), wavelets analysis, empirical mode decomposition (EMD), Hilbert-Huang transform (HHT), etc. however, these is still a need for human to interpret vibration signature of faults and it is regarded as one of the major challenge in vibration condition monit
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SALIM, Badran Jasim, and Oday Ahmed JASIM. "CAS WAVELETS METHOD TO SOLVE REACTION-DIFFUSION SYSTEM AND COMPARE IT WITH (G.F.E) METHOD." Periódico Tchê Química 17, no. 35 (2020): 1110–23. http://dx.doi.org/10.52571/ptq.v17.n35.2020.91_salim_pgs_1110_1123.pdf.

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Wavelet analysis plays a prominent role in various fields of scientific disciplines. Mainly, wavelets are very successfully used in signal analysis for waveform representation and segmentation, time-frequency analysis, and fast algorithms in the propagation equations and reaction. This research aimed to guide researchers to use Cos and Sin (CAS) to approximate the solution of the partial differential equation system. This method has been successfully applied to solve a coupled system of nonlinear Reaction-diffusion systems. It has been shown CAS wavelet method is quite capable and suited for f
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37

PABEL, ROLAND, ROBIN KOCH, GABRIELA JAGER, and ANGELA KUNOTH. "FAST EMPIRICAL MODE DECOMPOSITIONS OF MULTIVARIATE DATA BASED ON ADAPTIVE SPLINE-WAVELETS AND A GENERALIZATION OF THE HILBERT–HUANG–TRANSFORMATION (HHT) TO ARBITRARY SPACE DIMENSIONS." Advances in Adaptive Data Analysis 02, no. 03 (2010): 337–58. http://dx.doi.org/10.1142/s1793536910000513.

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The Hilbert–Huang-Transform (HHT) has proven to be an appropriate multiscale analysis technique specifically for nonlinear and nonstationary time series on non-equidistant grids. It is empirically adapted to the data: first, an additive decomposition of the data (empirical mode decomposition, EMD) into certain multiscale components is computed, denoted as intrinsic mode functions. Second, to each of these components, the Hilbert transform is applied. The resulting Hilbert spectrum of the modes provides a localized time-frequency spectrum and instantaneous (time-dependent) frequencies. For the
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38

Liu, Naihao, Jinghuai Gao, Zhuosheng Zhang, Xiudi Jiang, and Qi Lv. "High-resolution characterization of geologic structures using the synchrosqueezing transform." Interpretation 5, no. 1 (2017): T75—T85. http://dx.doi.org/10.1190/int-2016-0006.1.

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The main factors responsible for the nonstationarity of seismic signals are the nonstationarity of the geologic structural sequences and the complex pore structure. Time-frequency analysis can identify various frequency components of seismic data and reveal their time-variant features. Choosing a proper time-frequency decomposition algorithm is the key to analyze these nonstationarity signals and reveal the geologic information contained in the seismic data. According to the Heisenberg uncertainty principle, we cannot obtain the finest time location and the best frequency resolution at the sam
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39

Chen, Hanbo, and Tonglin Li. "3-D marine controlled-source electromagnetic modelling in an anisotropic medium using a Wavelet–Galerkin method with a secondary potential formulation." Geophysical Journal International 219, no. 1 (2019): 373–93. http://dx.doi.org/10.1093/gji/ggz305.

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SUMMARY This paper presents a new algorithm for solving 3-D MCSEM modelling problems in an anisotropic medium using a Wavelet–Galerkin method (WGM) based on compactly supported Daubechies wavelets which are differentiable according to the requirement. In order to avoid the source singularity, we adopted a secondary potential formulation for the quasi-static Maxwell's equation. The primary field on the modelling domain is calculated using fast Hankel transform. The domain can be discretized by locally intensive nodes to deal with the model's complexity, which is observed to improve the accuracy
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40

Gholami, Ali. "A fast automatic multichannel blind seismic inversion for high-resolution impedance recovery." GEOPHYSICS 81, no. 5 (2016): V357—V364. http://dx.doi.org/10.1190/geo2015-0654.1.

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The inversion of seismic reflection data for acoustic impedance (AI) is a common and accepted method for the interpretation of poststack seismic data. The original mathematical problem is nonlinear due to the nonlinearity of relation between the AI and the earth reflectivity series and also the insufficiency of information about the source wavelet. Furthermore, the problem is ill posed due to the lack of low and high frequencies in the data. We have developed a multichannel blind inversion and solved it for obtaining the AI model and the wavelet directly from seismic reflection data. We found
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41

BUI, T. D., G. Y. CHEN, and L. FENG. "AN ORTHONORMAL–SHELL–FOURIER DESCRIPTOR FOR RAPID MATCHING OF PATTERNS IN IMAGE DATABASE." International Journal of Pattern Recognition and Artificial Intelligence 15, no. 08 (2001): 1213–29. http://dx.doi.org/10.1142/s0218001401001465.

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Invariance and low dimension of features are of crucial significance in pattern recognition. This paper proposes a novel orthonormal shell Fourier descriptor that satisfies all of these demands. This method first performs orthonormal shell decomposition on the line moment that is obtained from the 2-D pattern, then applies Fourier transform on each scale of the shell coefficients. Unlike other existing wavelet-based methods, our method allows applying common orthonormal wavelets, such as Daubechies, Symmlet and Coiflet, therefore it is simple to implement. We study the structure of the filter
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42

Xue, Xiaofeng, Xuefeng Chen, Xingwu Zhang, Baijie Qiao, and Jia Geng. "Hermitian Mindlin Plate Wavelet Finite Element Method for Load Identification." Shock and Vibration 2016 (2016): 1–24. http://dx.doi.org/10.1155/2016/8618202.

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A new Hermitian Mindlin plate wavelet element is proposed. The two-dimensional Hermitian cubic spline interpolation wavelet is substituted into finite element functions to construct frequency response function (FRF). It uses a system’s FRF and response spectrums to calculate load spectrums and then derives loads in the time domain via the inverse fast Fourier transform. By simulating different excitation cases, Hermitian cubic spline wavelets on the interval (HCSWI) finite elements are used to reverse load identification in the Mindlin plate. The singular value decomposition (SVD) method is ad
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43

Yang, Shun-Hsing, Jyh-Jong Liao, Yi-Wen Pan, and Peter Tian-Yuan Shih. "Landslide site delineation from geometric signatures derived with the Hilbert–Huang transform for cases in Southern Taiwan." Open Geosciences 12, no. 1 (2020): 928–45. http://dx.doi.org/10.1515/geo-2020-0187.

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AbstractLandslides are a frequently occurring threat to human settlements. Along with global climate change, the occurrence of landslides is the forecast to be even more frequent than before. Among numerous factors, topography has been identified as a correlated subject and from which hillslope landslide-prone areas could be analyzed. Geometric signatures, including statistical descriptors, topographic grains, etc., provide an analytical way to quantify terrain. Various published literature, fast Fourier transform, fractals, wavelets, and other mathematical tools were applied for this paramete
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44

Ranjan, Kumar Kaushik, Sandeep Kumar, Amit Tyagi, and Ambuj Sharma. "An adaptive wavelet Galerkin scheme for solving contact problems based on elliptic variational inequalities of the first kind." Engineering Computations 36, no. 4 (2019): 1258–81. http://dx.doi.org/10.1108/ec-07-2018-0294.

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Purpose The real challenge in the solution of contact problems is the lack of an optimal adaptive scheme. As the contact zone is a priori unknown, successive refinement and iterative method are necessary to obtain a high-accuracy solution. The purpose of this paper is to provide an optimal adaptive scheme based on second-generation finite element wavelets for the solution of non-linear variational inequality of the contact problem. Design/methodology/approach To generate an elementary multi-resolution mesh, the authors used hierarchical bases (HB) composed of Lagrange finite element interpolat
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45

Everett, Thomas H., Emily E. Wilson, Sander Verheule, Jose M. Guerra, Scott Foreman, and Jeffrey E. Olgin. "Structural atrial remodeling alters the substrate and spatiotemporal organization of atrial fibrillation: a comparison in canine models of structural and electrical atrial remodeling." American Journal of Physiology-Heart and Circulatory Physiology 291, no. 6 (2006): H2911—H2923. http://dx.doi.org/10.1152/ajpheart.01128.2005.

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Several animal models of atrial fibrillation (AF) have been developed that demonstrate either atrial structural remodeling or atrial electrical remodeling, but the characteristics and spatiotemporal organization of the AF between the models have not been compared. Thirty-nine dogs were divided into five groups: rapid atrial pacing (RAP), chronic mitral regurgitation (MR), congestive heart failure (CHF), methylcholine (Meth), and control. Right and left atria (RA and LA, respectively) were simultaneously mapped during episodes of AF in each animal using high-density (240 electrodes) epicardial
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46

Gersztenkorn, Adam. "A new approach for detecting topographic and geologic information in seismic data." GEOPHYSICS 77, no. 2 (2012): V81—V90. http://dx.doi.org/10.1190/geo2011-0216.1.

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Interpreting 3D seismic volumes can be an intensive and time-consuming endeavor. Algorithms that provide additional information and expedite this process can therefore be useful tools for the interpreter. To further this goal, an algorithm that gives a topographic perspective of seismic data is described. After applying the continuous wavelet transform to the data, templates having a directional orientation are constructed locally in the complex wavelet domain for a number of scales. For each scale, a complex matrix is formed having real and imaginary parts, which are independently designed fo
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47

"Harmonic wavelet analysis." Proceedings of the Royal Society of London. Series A: Mathematical and Physical Sciences 443, no. 1917 (1993): 203–25. http://dx.doi.org/10.1098/rspa.1993.0140.

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A new harmonic wavelet is suggested. Unlike wavelets generated by discrete dilation equations, whose shape cannot be expressed in functional form, harmonic wavelets have the simple structure ω(x) = {exp(i4π x ) - exp(i2π x )}/i2π x . This function ω(x) is concentrated locally around x = 0, and is orthogonal to its own unit translations and octave dilations. Its frequency spectrum is confined exactly to an octave band so that it is compact in the frequency domain (rather than in the x domain). An efficient implementation of a discrete transform using this wavelet is based on the fast Fourier tr
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48

H, Venkatesh. "Fusion of Satellite Images in Transform Domain." Satellite Oceanography and Meteorology, September 4, 2018. http://dx.doi.org/10.18063/som.v0i0.610.

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Unique—Image fusion in light of the wavelet and fourier trans-form comes about rich multispectral points of interest yet gives less spatial subtle elements from source images. Wavelet transform performs well at straight highlights yet not at non-direct discontinuities since Wavelets don't utilize the geometric properties of structures. Curvelet transforms defeat such troubles in include rep-resentation. A novel Image fusion rule by means of high pass balance utilizing Local Magnitude Ratio (LMR) in Fast Discrete Curvelet Transforms domain (FDCT) and Discrete wavelet transform (DWT) is characte
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49

Moca, Vasile V., Harald Bârzan, Adriana Nagy-Dăbâcan, and Raul C. Mureșan. "Time-frequency super-resolution with superlets." Nature Communications 12, no. 1 (2021). http://dx.doi.org/10.1038/s41467-020-20539-9.

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AbstractDue to the Heisenberg–Gabor uncertainty principle, finite oscillation transients are difficult to localize simultaneously in both time and frequency. Classical estimators, like the short-time Fourier transform or the continuous-wavelet transform optimize either temporal or frequency resolution, or find a suboptimal tradeoff. Here, we introduce a spectral estimator enabling time-frequency super-resolution, called superlet, that uses sets of wavelets with increasingly constrained bandwidth. These are combined geometrically in order to maintain the good temporal resolution of single wavel
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50

"Wavelet Transforms Applications and Interpretation Based on the Signal Genesis." International Journal of Engineering and Advanced Technology 9, no. 1S (2019): 30–37. http://dx.doi.org/10.35940/ijeat.a1006.1091s19.

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A signal from any measurement system provides insight into its genesis, thereby enabling an understanding of a certain activity or phenomenon. Seismic signals, radar echo signals, physiological signals, signals from specially fabricated instruments such as MRI, CT scanner all provide information by using an analysis that resolves the signal into its frequency components. While the Fourier transform and its fast – evaluating algorithm known as FFT are standard for such analysis, there are presently additional signal transforms in use, of which “ Wavelets” or Wavelet transform or wavelet decompo
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