Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 116 for “"wavelet analysis"”.
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Wavelet analysis of temporal data
This thesis considers the application of wavelets to problems involving multiple series of temporal data. Wavelets have proven to be highly effective at extracting frequency information from data. Their multi-scale nature enables the efficient description of both transient and long-term signals. …
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Wavelet analysis of geomagnetic jerks
… core (through a so-called geo-dynamo process). A wavelet tool was programmed in MATLAB and a wavelet analysis applied to detect and characterize singular events, or jerks, in the time series made of monthly mean values of the east component of the geomagnetic field from 45 selected worldwide …
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Wavelet analysis of ULF magnetospheric waves
<p>Wavelet analysis is used to analyze magnetometer data and is compared to the traditional spectrogram technique, in particular, with respect to structured Pc 1--2 emissions. This results in the conclusion that the frequency modulation evident in Pearl pulsations is not continuous, but is …
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Photopeak detection and quantification using wavelet analysis
… uum, electronics noise, and peak overlap. The wavelet transform stands out among many potential solutions of this problem, owing to its ability to de-noise noisy signals, pattern matching, and simultaneous multi-resolution signal analysis. In this thesis, a novel wavelet-based algorithm for …
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Multiresolution spherical wavelet analysis in global seismic tomography
… type of parameterization, performed by means of wavelet functions. It is known from the classical Fourier theory that a signal can be expressed as the sum of a, possibly infinite, series of sines and cosines. This sum is often referred as a Fourier expansion. The big disadvantage of a Fourier …
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Wavelet Analysis and its Application to Modulation Characterization
Wavlet analysis and its advantages in determining time-varying characteristics are discussed. The Morlet wavelet is defined and procedures for choosing its parameters are described. The recovery of modulation characteristics using the Morlet wavelet is demonstrated. Hydrodynamic linear stability is …
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Wavelet Analysis of Extreme Wind Loads on Low-Rise Structures
… pressure peaks. In this work, we show how wavelet analysis and time-scale representation can be used to establish an intermittency factor that characterizes energetic turbulence events in the atmospheric flows. Moreover, we relate these events to the occurrence of extreme negative peak …
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PULSED RADAR TARGET RECOGNITION BASED ON MICRO-DOPPLER SIGNATURES USING WAVELET ANALYSIS
… such as the short-time Fourier transform, the wavelet packet transform and the Haar transform to extract key μ-D signature related features from the time-frequency plane representation of the echo signal. These μ-D signature based features are combined with relative range profile based ones …
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Automated wavelet analysis of low resolution gamma-ray spectra and peak area uncertainty
… with better algorithms. The method based on the wavelet transform and non-negative least squares (NNLS) are discussed in this thesis. Several improvements are made for the wavelet algorithm itself and different options can be configured in the MATLAB code. The partial or whole spectrum can be …
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Detecting the socioeconomic conditions of urban neighborhoods through wavelet analysis of remotely sensed imagery
Wavelet analysis is an efficient approach to studying textural patterns at different scales. Artificial neural networks can learn very complex patterns in the data and could be an efficient classifier. However, whether wavelet analysis, in combination with artificial neural networks or other …
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Optoelectronic Multifractal Wavelet Analysis for Fast and Accurate Detection of Rainfall in Weather Radar Images
… of rainfall. The process employs multifractal analysis using directional Gabor wavelets for accurate detection of the rain events. An optoelectronic joint transform correlator is proposed to provide ultra fast processing and wavelet analysis. Computer simulations of the proposed system show …
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Application of Wavelet Analysis and Cross-Correlation Techniques to Wide Area Monitoring of Power Systems
… presents a method for the real-time automated analysis and visualization of time-synchronized phasor measurements for online event detection, location, and system characterization. The method employs cross-correlation and wavelet multi-resolution signal processing techniques for noise removal. …
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Large Eddy Simulation and Wavelet Analysis of the Flow Field around a Surface Mounted Prism
… case data. Also, spectral and cross-spectral analysis are carried out using complex Morlet wavelet transform to investigate pressure-velocity relation. The study shows that the nonlinearity in the relationship of velocity-pressure is detected using wavelet bicoherence.
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Application of Wavelet Analysis for Examining Climate and Meltwater Runoff in the Paakitsoq Region, West Greenland
… air temperature and proglacial discharge using wavelet analysis in order to establish the variability of discharge on short (<1-3 days) timescales and how this is driven by meteorological factors on similar (<1-4 days) timescales. Wavelets produce a high-resolution breakdown of the time series …
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Power Transformer Partial Discharge (PD) Acoustic Signal Detection using Fiber Sensors and Wavelet Analysis, Modeling, and Simulation
… part of this thesis focuses on the PD signal analysis from an on-site PD measurement of the in-house design fiber optic sensors (by Virginia Tech, Center for Photonics Technology). Several commercial piezoelectric transducers (PZTs) were also used to compare the measurement results. The signal …
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Multiresolution wavelet analysis of event-related EEG potentials using ensemble of classifier data fusion techniques for early diagnosis of Alzheimer's disease
… ERP signals for the early detection of AD. The analysis of the ERP signals is accomplished through multiresolution wavelet decomposition, producing time-frequency features in successive spectral bands. In previous studies, these feature sets were concatenated and used as inputs to a neural …
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Estimation of LRD present in H.264 video traces using wavelet analysis and proving the paramount of H.264 using OPF technique in wi-fi environment.
… the LRD a few studies are carried out and Wavelet-based estimator is selected for the research because Wavelets incarcerate both time and frequency features in the data and regularly provides a more affluent picture than the classical Fourier analysis. The Wavelet used to estimate the …
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Adaptive Fourier Analysis For Unequally-Spaced Time Series Data
Fourier analysis, Walsh-Fourier analysis, and wavelet analysis have often been used in time series analysis. Fourier analysis can be used to detect periodic components that have sinusoidal shape; however, it might be misleading when the periodic components are not sinusoidal. Walsh-Fourier analysis …
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