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A System for the Microanalysis and Automatic classifiction of Sleep Electroence...
Ana Maria Perfeito Tomé; José Carlos PríncipeAutomatic sleep analysis has been a subject of interest since the sixties, mainly because of the growing importante of various sleep disorders. The visual analysis of sleep recordings is a tedious, laborious, time-consuming and expensive task. During a single night recording 400-500 meters of paper are produced and the visual analysis usually takes several hours of an expert.This work presents an environment wh...
Digital Compression of Audio Signals Applying Perceptual Criteria and Backward ...
João Manuel de Oliveira e Silva Rodrigues; Ana Maria Perfeito ToméIn this work, the problem of digital coding of high quality audio signals is analised, and the principies of perceptual coding are identified as the most satisfactory solution. We present a synthesis of the perceptual coding systems found in the literuture, stressing their common structure, and we characterize the possihle variants that each module in that structure allows. Based on this study, a new perceptual...
Automatic System for Monitoring of Neurophysiologic Sleep Examinations
José Manuel de Carvalho Nunes de Oliveira; Ana Maria Perfeito ToméSleep studies require the analysis of different physiological variables (EEG/EOG activities, respiratory rate, heart beat rate and 02 desaturation), generating a huge amount of data coming from different sources. Some automatic systems have been developed, but their use on a day-to-day basis is very seldom. (...)Keywords: sleep examinations; object oriented programmingM.S., 1996more info. http://opac....
Codificação Perceptual de Áudio usando Quantização Retro-Adaptativa
João Manuel Rodrigues; Ana Maria Perfeito ToméThis paper presents a new coding/compression algorithm for high-quality digital audio signals. The new codercomprehends a nonuniform filter bank, gain-adaptive logaritbmic quantizers, arithmetic coding, and an explicit psychoacoustic model that adapts the quantizers according to perceptual criteria. The new system differs from other perceptual coders in that its quantizers are backward-adaptive: the adaptation ...
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