Encontrados 66 documentos, a visualizar página 1 de 7
Sistema de Codificação de Voz de Alta Qualidade com Banco de Filtros
Elizabeth Fernandez; Luís Nuno Silva; João Rodrigues; Ana Maria Tomé; Francisco VazThis paper describes a high quality speech coding system based in the ITU Recommendation G.722 “7 kHz audio coding within 64 kbit/s”. Provides a high-level description of the recommended algorithm and a brief discussion about the arithmetical choices, which have been made. Some performance results are provided. ; Este artigo descreve um sistema de codificação ...
Sistema Integrado para Análise e Classificação Automática do Electroencefalogra...
Osvaldo Pacheco; Francisco VazIn this paper we describe a system for automatic all night analysis of sleep, based on neural networks. The system consists of a three step analysis. The first step is the recognition of elementary patterns in EEG (delta, alpha,spindle and K complex waves), EOG and EMG, and spectral analysis for background activity. The second step is the determination of sleep stages based on these par...
An Implementation of the Klatt Speech Synthesiser
Luis Miguel Teixeira de Jesus; Francisco Vaz; José Carlos PrincipeIn this work it is described a software tool implementing the Klatt synthesiser to be used on a teaching laboratory. The user interface allows an easy edition of the synthesis parameters, thus the student may quick and easily change the phonetic characteristics of a vowel and listen to the result or seeing its time or frequency properties. ; Neste trabalho descreve-se a implementa&cced...
Representação Visual do Modelo Articulatório para o Estudo da Produção da Fala
António Branco; Ana Maria Tomé; Francisco VazIn this paper we present the description of an articulatory speech synthesiser which is to be used as a tool for the study of speech production. The sound might be produced as the result of vocal tract configurations edited by the user. It also allows the study of the inverse problemthe estimation of a vocal tract configuration given a speech sound. ; Neste artigo descreve-se a im...
Reconhecimento do Orador
João Paulo Guedes; Pedro Miguel Figueirôa; António Teixeira; Francisco VazVerification of a person identity based in voice alone is an evolving technology with applications in secure access to information, access control to buildings, and telecommunications in general. This work addresses several of the possibilities available in the implementation of an automatic speaker verification system, independent of text, based in phoneme recognition. We studied ...
Robot Autonomous Navigation: Sensorial Data Interpretation and Local Navigation
Vítor Manuel Ferreira dos Santos; Francisco VazThis thesis focuses on the problems of local navigation of mobile robots. The main idea consists on the development of ultrasonic perception maps, by means of neural networks, and to perform local navigation based on those maps. The local navigation task is integrated in a global architecture along with some other tasks to allow complete navigation operations. (...)Keywords: mobile robotics; local navigati...
Computer Based System for Sleep Staging and Micro Arousal Detection
Osvaldo Manuel da Rocha Pacheco; Francisco VazIn today's developed societies, the number of people affected by sleep disorders is growing by the day. To handle a growing number of patients, there has been a steady growth in the number of sleep analysis clinics and laboratories. Human sleep stages are hand-scored by an expert and this is a laborious, time consuming and difficult task. (...)Keywords: sleep; neural networks; automatic decision; supervisi...
Digital Image Edge Detection Using Neural Networks
Armando José Formoso de Pinho; Luís Henrique Martins Borges de Almeida; Francisco VazIn this thesis we address the problem of edge detection. The fundamental idea that motivated the work is related to the philosophy with which the problem is addressed. Our line of work was in the direction of investigating methods that could be able to design specialized edge detectors, instead of general purpose operators. (...)keywords: edge detection; neural networks; backpropagation; edge quality evaluation...
Brain Potentials Related to the Verifiction of Phrases
António André Esteves; Francisco VazThe purpose of the present work is to determine if it is possible to get evidences that happen during the sentence verification task. (...)Keywords: Eent-brain; related potentials; N400; semantic processing; context; classification; sentece verificationMs.C., 1992more info. http://opac.ua.pt/F/?func=find-b&find_code=SYS&REQUEST=000049507 ; Com o presente trabalho pretende averiguar-se se &eac...
Speaker Recognition using Neural Networks
António Joaquim da Silva Teixeira; Francisco VazThis work presents an experience in using neural networks in the area of speaker recognition, in the two variants of verification and identification. The developed system has a classical architecture in the area. It uses blocks for feature extraction, comparision, references and decision. (...)Keywords: speaker identification; speaker verification; filter bank; neural networks; gamma model; gamma memory; f...
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