2000
Autores
Cunha, JPS; de Oliveira, PG;
Publicação
IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING
Abstract
In this paper, we present some original theoretical aspects of a fast nonlinear association measure based on the work of Cramer. The features of this new measure-the V measure-when applied to biosignals are also shown using simulated time series. A comparative study with other well-known association measures available in the literature of biosignals is presented, V was found to be twice as fast and more robust to nonlinearities than the classical cross-correlation ratio (r(2)) and more than 100 times faster than the nonlinear regression coefficient (h(2)), presenting similar behavior in the presence of nonlinear simulated situations. This new measure is very fast and versatile, It is appropriate to deal with nonlinear relations presenting usually a sharp peak in the association function enabling a high degree of selectivity for maxima detection. It seems to constitute an improvement over linear methods of association which is faster and more robust to the existing nonlinearities. It can be used as an alternative to more complex nonlinear association measures when computational speed is an important feature.
1983
Autores
Guedes De Oliveira, P; Queiroz, C; Lopes Da Silva, F;
Publicação
Electroencephalography and Clinical Neurophysiology
Abstract
2012
Autores
Duarte, C; Oliveira, HP; Magalhães, F; Tavares, VG; Campilho, AC; de Oliveira, PG;
Publicação
Proceedings of the IEEE Global Engineering Education Conference, EDUCON 2012, Marrakech, Morocco, April 17-20, 2012
Abstract
This paper presents two initiatives run by groups of engineering students at the University of Porto: the Microelectronics Students' Group and BioStar. These groups are student-led initiatives that promote different scientific fields through self-guided projects. Both experiences have proven to be very successful in increasing the undergraduate student's interest in science and technology. This work reports the activities, organization and main methodologies employed by these groups, which can be seen as successful approaches to enhance the technical curriculum of students. © 2012 IEEE.
1992
Autores
de Oliveira, PG; Cunha, JP; da Silva, AM;
Publicação
Acta Neurochirurgica, Supplement
Abstract
In this paper the requirements of Neurophysiology and Neurotraumatology monitoring are analyzed. As a result a set of designated systems were developed by the authors a short description of which is given in the paper. Finally the future perspectives and problems to be faced are briefly described.
1980
Autores
Guedes De Oliveira, PHH; Lopes Da Silva, FH;
Publicação
Electroencephalography and Clinical Neurophysiology
Abstract
A method for the analysis of topographical relations of EEG epileptiform transients based on a statistical approach is described. The degree of time association of those transients recorded in pairs of derivations, or in 3 (triads), 4 (tetrads) or more derivations is estimated, using the ?2 statistic. Pairs of derivations which are found to be significantly associated are tabulated. This information is also graphically displayed on a computer drawing of the head (10-20 system). The same is done for triads, tetrads or higher order associations. The number of phase reversals between epileptiform transients found in significantly associated pairs of derivations is also computed. The resulting spatial displays enable a visualization of the location of the dominant epileptogenic area and of the spread of epileptiform activity over the head. © 1980.
1991
Autores
De, VB; Principe Jose, C; de, OPG;
Publicação
Neural Networks for Signal Processing
Abstract
We present a generalization of Widrow's adaptive linear combiner with an adaptive recursive memory. Expressions for memory depth and resolution are derived. The LMS procedure is extended to adapt the memory depth and resolution so as to match the signal characteristics. The particular memory structure, gamma memory, was originally developed as part of a neural net model for temporal processing.
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