Wavelet Transforms
Mostrando 1-12 de 23 artigos, teses e dissertações.
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1. 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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2. 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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3. 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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4. Chaotic synchronization of vibrations of a coupled mechanical system consisting of a plate and beams
In this paper mathematical model of a mechanical system consisting of a plate and either one or two beams is derived. Obtained PDEs are reduced to ODEs, and then studied mainly using the fast Fourier and wavelet transforms. A few examples of the chaotic synchronizations are illustrated and discussed.
Lat. Am. j. solids struct.. Publicado em: 2013-01
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5. 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
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6. Experimental study of the propagation of a far-field disturbance in the turbulent flow through square array tube banks
This paper presents the experimental analysis of the propagation of a disturbance with a fixed frequency in the incidence velocity of the cross flow through a tube bank, and its influence on the velocity fluctuations inside the bank. The disturbance is generated outside the bank by vortex shedding from an obstacle. The tube banks investigated had square arra
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2009-09
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7. Análise da transformada wavelet direcional adaptativa na codificação de imagens
This work presents a method for the numerical stability analysis of adaptive lifting-based directional transforms. The goal is to investigate the relation between the directions set in the lifting scheme and the reconstruction quality of the corresponding bases. This new method is based on the variation in frequency of the condition number of the synthesis p
Publicado em: 2009
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8. Use of Wavelet Transforms to Detect Abnormal Frequency Variation in Distributed Generation Systems / Utilização da transformada de Wavelet para detectar variações anormais de freqüência em sistemas de geração distribuída
This dissertation focuses the importance of registering eventual frequency variations in Electric Power System which may cross the established limits for normal operation. These can cause serious problems in the operation of sensitive equipments connected to the electric grid, such as the turbo-generators employed in thermoelectric plants. For power system f
Publicado em: 2009
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9. Avaliação do desempenho de transformadas sobrepostas nos codificadores padrão JPEG2000 E H.264/AVC
This work aims to evaluate the performance presented by lapped transforms, wavelets and DCT in standards JPEG2000 and H.264/AVC coders. Even though there is much of information about the comparison of those transforms in many coders, there is little information available in literature relative to the performs of the performs of these transforms in the coders
Publicado em: 2008
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10. OUTFLOW FORECAST BASED ON ARTIFICIAL NEURAL NETORKS AND WAVELET TRANSFORM / PREVISÃO DE VAZÃO POR REDES NEURAIS ARTIFICIAIS E TRANSFORMADA WAVELET
The hydroelectricity system is responsible for 83.7% of the electric energy generated at Brazil. Therefore, the generation of electric power in Brazil depends basically on the natural flow rates distributed by twelve basins in the country. The quality of prediction of natural flow is of crucial importance for the Brazilian governmental agency, ONS (from the
Publicado em: 2008
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11. Sistemas inteligentes e wavelets para previsÃo de vento e geraÃÃo eÃlica / Intelligent systems and wavelets for forecast winds and wind energy
VÃrios estudos jà comprovaram que o potencial eÃlico brasileiro, principalmente no nordeste, onde os ventos tÃm uma importante caracterÃstica de complementaridade em relaÃÃo Ãs vazÃes do rio SÃo Francisco, pode contribuir significativamente para o suprimento de energia elÃtrica. O aproveitamento deste potencial eÃlico aumentaria a capacidade de g
Publicado em: 2008
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12. Experimental study of the bistable flow in tube arrays
Flow through circular cylinder arrays are commonly found in several engineering application as offshore structures, heat exchangers, transmission lines and chimneys, therefore the understanding of the several phenomena that occur due the interaction between flowing fluid and these structures is very important. This work analyzes experimentally the presence o
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2006-06