Wavelet Transform
Mostrando 13-24 de 158 artigos, teses e dissertações.
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13. 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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14. USO DE RECEPTORES GPS DE 100 HZ NA DETECÇÃO DE DEFLEXÕES VERTICAIS MILIMÉTRICAS DE PONTES DE CONCRETO DE PEQUENO PORTE
As últimas quatro décadas foram importantes para o desenvolvimento da malha rodoviária brasileira. O país recebeu incentivos financeiros para a sua expansão e diversas soluções estruturais para pontes e viadutos foram criadas. Em paralelo a este desenvolvimento, houve nos últimos anos um crescimento significativo dessas estruturas em estágio avança
Bol. Ciênc. Geod.. Publicado em: 2015-06
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15. 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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16. 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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17. Damage identification from uniform load surface using continuous and stationary wavelet transforms
Derived from flexibility matrix, Uniform Load Surface (ULS) is used to identify damages in beam-type structures. This method is beneficial in terms of more participating the lower order modes and having less prone to noise and irregularities in the measured data in comparison with the original flexibility matrix technique. Therefore, these characteristics ma
Lat. Am. j. solids struct.. Publicado em: 2014-10
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18. Sistema computacional para auxílio ao diagnóstico em exames de tuberculose animal
The results obtained in evaluating the efficiency of a Neuro-Fuzzy System NEFCLASS (Neuro-Fuzzy Classification) in image classification of cattle tuberculosis, based on its texture features extracted using the wavelet transform are presented. For testing, images of animal tissues diagnosed with tuberculosis were used, as provided by the Tuberculosis Laborato
Arq. Bras. Med. Vet. Zootec.. Publicado em: 2013-04
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19. Cutting force response in milling of Inconel: analysis by wavelet and Hilbert-Huang Transforms
We study the milling process of Inconel. By continuously increasing the cutting depth we follow the system response and appearance of oscillations of larger amplitude. The cutting force amplitude and frequency analysis has been done by means of wavelets and Hilbert-Huang transform. We report that in our system the force oscillations are closely related to th
Lat. Am. j. solids struct.. Publicado em: 2013-01
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20. Algoritmo híbrido e inteligente para o diagnóstico das condições operativas de transformadores de potência no contexto da qualidade da energia elétrica / Hybrid intelligent algorithm for the diagnosis of operating conditions of power transformers in the context of power quality
This research aimed to develop an algorithm able to diagnose the operating conditions of power transformers. The variables considered to classify the presented conditions were the normally used by differential protection logic, i.e., the differential current and the harmonic content in the signals in analysis. Moreover, the relationship between some phenomen
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 12/07/2012
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21. Desenvolvimento de ferramenta de comparação de técnicas de processamento de sinais para determinar fadiga muscular por meio do sinal emg / Toolkit development for signals processing technics comparison to detect muscular fadigue by EMG signal
This study aimed to development of a computational tool for electromyographic signal (EMG) analysis by signal processing techniques to determine muscular fatigue. With Ethics Committee of Federal University of Goiás approve were recorded from the dominant biceps brachii of 10 volunteers, that did not ever had muscular disease. The protocol consisted on get
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 09/07/2012
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22. Análise de eventos em redes de distribuição por meio das transformadas Wavelet e S / Event analysis in distribution networks using Wavelet and S transform
O presente trabalho apresenta uma comparação de duas técnicas para a análise tempo - frequência em análise de qualidade de energia elétrica para sinais de tensão que contenham distúrbios individuais ou simultâneos. Dessa forma, o objetivo, desta dissertação, é encontrar uma ferramenta que forneça as características e parâmetros para a localiz
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 02/04/2012
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23. Aplicação da codificação ROI e WT para compressão de imagens DICOM-CT / Aplication of the ROI coding and WT for compression DICOM-CT images
O armazenamento e a transmissão de grande quantidade de imagens médicas constituem um campo ativo de pesquisa. Dispositivos de imagem geram muitos dados por paciente. Além disso, deve-se prover armazenamento de longo prazo bem como uma transmissão eficiente. Esquemas de compressão atuais produzem taxas de compressão elevadas e com perda de qualidade. U
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 30/03/2012
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24. Desenvolvimento de um Sistema de Auxílio ao Diagnóstico de Pneumonia na Infância Utilizando Visão Computacional / Development of a System of Aid to the Diagnosis of Pneumonia in Children Using Computer Vision
This work aims to develop a system to aid in the diagnosis of pneumonia by computer, termed pneumocad, which aims to identify chest radiographies compatible with the disease. Techniques were used for the recognition of patterns in textures through the decomposition of the wavelet transforms of the features extracted from the decomposition and classification
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 22/03/2012