Quantization Techniques
Mostrando 1-12 de 14 artigos, teses e dissertações.
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1. Proposta de um sistema de detecção e classificação de intrusão em redes de computadores baseado em transformadas wavelets e redes neurais artificiais
As the Internet has become an enormous interconnected network, the information security today is very important to guarantee confidentiality, integrity and availability of computing resources. Advanced Intrusion Detections Systems (IDS) should be capable of identifying malicious actions that may compromise these guarantees, as quickly as possible. In this wo
Publicado em: 2009
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2. Mistura de cores: uma nova abordagem para processamento de cores e sua aplicação na segmentação de imagens / Colors mixture: a new approach for color processing and its application in image segmentation
Inspired on the techniques used by painters to overlap layers of various hues of paint to create oil paintings, and also on observations of the distribution of cones in human retina for the interpretation of these colors, this thesis proposes an image processing technique based on color mixing. This is a static color quantization method that expresses the mi
Publicado em: 2009
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3. Channel state feedback for the downlinkwith multiple antennas / Realimentação de informação de canal para downlink com multiplas antenas
Multiuser communication strategies, together with the use of multiple antennas, result in better performance when compared to the point-to-point approach. However, they are highly dependent on knowledge of channel state information at the transmitter, which in general requires that the receivers feed back the estimated channel. The focus of this work is the
Publicado em: 2009
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4. Intravascular ultrasound: tridimensional quantification and analysis / Análise e quantificação tridimensional em imagens de ultra-som intravascular
INTRODUCTION: Several efforts for in vivo atherosclerotic plaque estimation has been realized worldwide. Current methods for related application are based on spectral analysis of backscattered ultrasound signals before intravascular image formation (IVUS), once there is not available techniques to perform composition analysis only from IVUS images. On this s
Publicado em: 2009
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5. Um modelo de compressão de imagens digitais baseado em quantização vetorial e transformações afins
The fractal compression is an emerging digital image coding technique which explores the self-similarity present in digital images, showing good fidelity between the original image and the reconstructed image, achieving high compression rates. However it has some weaknesses and because it demands a considerable computational complexity commonly is used the a
Publicado em: 2008
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6. SeleÃÃo de protÃtipos: combinando auto-geraÃÃo de protÃtipos e mistura de gaussianas
Prototype selection is a machine learning scheme in which the main purpose is to choose pattern vectors from the training dataset that achieve a better fit to data point distributions and maintain class separation. The aim of this kind of technique is to find the smallest possible prototype set that minimizes the classification error rate. Prototype-based st
Publicado em: 2008
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7. TRATAMENTO E COMPRESSÃO BASEADA EM WAVELETS PARA DADOS ADQUIRIDOS POR SENSORES / TREATMENT AND WAVELET-BASED COMPRESSION OF SENSOR DATA
This dissertation introduces a strategy to develop a compression method for sensor data inspired on the JPG2000 techniques. The strategy adopted processes data streams much in the same way as signal processing. Due to the unstable nature of sensor data, noise is added to the original signal. This noise is detected and treated while the signal is cleaned and
Publicado em: 2007
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8. Mapa auto-organizÃvel com campo receptivo adaptativo local para segmentaÃÃo de imagens
A new self-organizing map with variable topology is introduced for image segmentation. The proposed network, called Local Adaptive Receptive Field Self-organizing Map (LARFSOM) is based on the Self-organizing Map (SOM) and Grow When Required (GWR). The model main features are: adaptive final number of nodes, variable topology, new node insertion based on sim
Publicado em: 2007
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9. Compressão de sinais de eletrocardiograma utilizando análise de componentes independentes / COMPRESSION OF ELETROCARDIOGRAMA SIGNALS USING ANALYSIS OF INDEPENDENT COMPONENTS
The continuing demand for high performance and low cost electrocardiogram processing systems have required the elaboration of even more efficient and reliable ECG compression techniques. The objective of this work is to evaluate the performance of an electrocardiogram (ECG) compression algorithm based on independent components analysis (ICA). To each of the
Publicado em: 2006
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10. Compressão Seletiva de Imagens Coloridas com Detecção Automática de Regiões de Interesse
There has been an increasing tendency on the use of selective image compression, since several applications make use of digital images and the loss of information in certain regions is not allowed in some cases. However, there are applications in which these images are captured and stored automatically making it impossible to the user to select the regions o
Publicado em: 2006
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11. Um metodo de compressão de audio baseado na codificação de Subbandas Wavelets
This work presents a method for audio compression based on wavelets sub-band quantization and coding, and proposes a coder based on that method. First, the work describes the Wavelet Transform with emphasis on the concepts of multi-resolution analyzes and their relationship with filtering processes and decomposition in sub-bands. A description of the Wavelet
Publicado em: 2001
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12. Técnicas neuronais de agrupamentos aplicadas à detecção de anomalias em mamogramas digitais
This work proposes the development of an intelligent system for analysis of digital mammograms, capable to detect and to classify masses and microcalcifications. The digital mammograms will be pre-processed through techniques of digital processing of images with the purpose of adapting the image to the detection system and automatic classification of the exi
Publicado em: 2001