Discrete Wavelet Transform
Mostrando 1-12 de 28 artigos, teses e dissertações.
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1. Wavelet-domain elastic net for clustering on genomes strains
Abstract We propose to evaluate genome similarity by combining discrete non-decimated wavelet transform (NDWT) and elastic net. The wavelets represent a signal with levels of detail, that is, hidden components are detected by means of the decomposition of this signal, where each level provides a different characteristic. The main feature of the elastic net i
Genet. Mol. Biol.. Publicado em: 29/11/2018
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2. Real-time premature ventricular contractions detection based on Redundant Discrete Wavelet Transform
Abstract Introduction Premature Ventricular Contraction (PVC) is among the most common types of ventricular cardiac arrhythmia. However, it only poses danger if the person suffers from a heart disease, such as heart failure. Hence, this is an important factor to consider in heart disease people. This paper presents an ECG real-time analysis system for PVC
Res. Biomed. Eng.. Publicado em: 26/07/2018
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3. A wavelet-based method for power-line interference removal in ECG signals
Abstract Introduction The analysis of electrocardiogram (ECG) signals allows the experts to diagnosis several cardiac disorders. However, the accuracy of such diagnostic depends on the signals quality. In this paper it is proposed a simple method for power-line interference (PLI) removal based on the wavelet decomposition, without the use of thresholding t
Res. Biomed. Eng.. Publicado em: 2018-01
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4. Matrix Damage Detection in Laminated Composite Structures by Discrete and Continuous Wavelet Transforms Using Vibration Modes
ABSTRACT: In this paper it was sought to enhance the potential damage detection, location and quantification of the Discrete and Continuous Wavelet Transforms in thin damaged laminated composite plates by a signal derived from vibration modes. To evaluate the ability of both transforms in the damage prognostic it was also proposed the use of Damage Indexes.
J. Aerosp. Technol. Manag.. Publicado em: 21/09/2017
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5. Influences of the signal border extension in the discrete wavelet transform in EEG spike detection
Abstract Introduction The discrete wavelet transform is used in many studies as signal preprocessor for EEG spike detection. An inherent process of this mathematical tool is the recursive wavelet convolution over the signal that is decomposed into detail and approximation coefficients. To perform these convolutions, firstly it is necessary to extend signal
Res. Biomed. Eng.. Publicado em: 12/09/2016
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6. Pulmonary crackle characterization: approaches in the use of discrete wavelet transform regarding border effect, mother-wavelet selection, and subband reduction
Introduction Crackles are discontinuous, non-stationary respiratory sounds and can be characterized by their duration and frequency. In the literature, many techniques of filtering, feature extraction, and classification were presented. Although the discrete wavelet transform (DWT) is a well-known tool in this area, issues like signal border extension, moth
Res. Biomed. Eng.. Publicado em: 2015-04
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7. Drowsiness detection for single channel EEG by DWT best m-term approximation
Introduction In this paper we propose a promising new technique for drowsiness detection. It consists of applying the best m-term approximation on a single-channel electroencephalography (EEG) signal preprocessed through a discrete wavelet transform. Methods In order to classify EEG epochs as awake or drowsy states, the most significant m terms from the wav
Res. Biomed. Eng.. Publicado em: 2015-04
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8. Contribuições para pós processamento da transformada wavelet na codificação roi e spiht com aplicação na transmissão de imagens / Contributions for post processing of wavelet transform with SPIHT ROI coding and application in the transmission of images
A área que trata de compressão de imagem com perdas é, atualmente, de grande importância. Isso se deve ao fato de que as técnicas de compressão permitem representar de uma forma eficiente uma imagem reduzindo assim, o espaço necessário para armazenamento ou um posterior envio da imagem através de um canal de comunicações. Em particular, o algoritm
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 31/01/2012
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9. A fault location method using Lamb waves and discrete wavelet transform
Non-destructive evaluation methods and signal process techniques are important steps in structural health monitoring systems to assess the structure integrity. This paper presents a method for fault location in aluminum beams based on time of flight of Lamb waves. The dynamic response signal captured from the structure was processed using the discrete wavele
J. Braz. Soc. Mech. Sci. & Eng.. Publicado em: 2012-12
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10. Análise das curvas de luz do CoroT usando diferentes processos comparativos: estimando períodos de rotação estelar / Corot light curves analysis using different comparative processes: estimating stellar rotation periods
Um dos principais objetivos do Grupo do CoRoT de Natal é a determinação do período de rotação para milhares de estrelas, um parâmetro fundamental para o estudo da história evolutiva estelar. Para estimar o período de rotação das estrelas e compreender as incertezas associadas resultantes, por exemplo, das descontinuidades nas curvas e (ou) das bai
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 30/12/2010
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11. A proposal for optimized analysis of transient currents in conductive materials. / Uma proposta para análise otimizada de correntes transitórias em materiais condutores.
In this work, a methodology is developed, based on the application of the moment method associated to a finite difference approximation, for time domain analysis of transient current distribution in conducting media. The computational procedure allows that long conductors with any cross section can be considered, approximated by filamentary elements. Thus, t
Publicado em: 2010
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12. Métodos de reamostragem de séries temporais baseados em wavelets. / Resampling methods for time series based on wavelets.
This paper reviews resampling methods based on wavelets as an alternative to the classic approaches which are, made in the time and frequency domains. These methods, known in the literature as wavestrap and wavestrapping, make use, respectively, of the discrete wavelet transform (DWT) and of the discrete wavelet packet transform (DWPT). Since only few result
Publicado em: 2010