2003
Autores
Romero, R; Frazao, O; Marques, PVS; Salgado, HM; Santos, JL;
Publicação
MEASUREMENT SCIENCE & TECHNOLOGY
Abstract
A fibre Bragg grating interrogation technique with tunable sensitivity is reported. It relies on the utilization of the edge filtering concept applied to a chirped fibre Bragg grating (CFBG) written in an erbium-doped fibre as the processing element. Through the combination of the optical gain properties of the erbium-doped fibre and of the distributed wavelength reflection characteristics of the CFBG, it is possible to achieve different reading sensitivities and amplification of the remote sensing signal.
2003
Autores
De Dutra, IC; Page, D; Costa, VS; Shavlik, J;
Publicação
Lecture Notes in Artificial Intelligence (Subseries of Lecture Notes in Computer Science)
Abstract
Ensembles have proven useful for a variety of applications, with a variety of machine learning approaches. While Quinlan has applied boosting to FOIL, the widely-used approach of bagging has never been employed in ILP. Bagging has the advantage over boosting that the different members of the ensemble can be learned and used in parallel. This advantage is especially important for ILP where run-times often are high. We evaluate bagging on three different application domains using the complete-search ILP system, Aleph. We contrast bagging with an approach where we take advantage of the non-determinism in ILP search, by simply allowing Aleph to run multiple times, each time choosing "seed" examples at random.
2003
Autores
Faustino Agreira, CI; Machado Ferreira, CM; Dias Pinto, JA; Maciel Barbosa, FP;
Publicação
Proceedings of the Universities Power Engineering Conference
Abstract
In this paper it is proposed an efficient steady-state contingency classification using the Rough Set Theory. This approach allows the evaluation of the importance of particular attributes and the elimination of redundant attributes from the decision domain. Moreover, the construction of a minimal subset of independent attributes ensuring the same quality of classification as the original set. The elimination of redundant attributes can help in identification of strong non-redundant classification rules. The developed methodology produces a classification of the system operation in four possible states. The methodology developed by the authors was applied to a test power network and the results obtained were analysed. Finally, some conclusions that provide a valuable contribution to the understanding of the power system security analysis are pointed out.
2003
Autores
Rego, G; Fernandes, JRA; Santos, JL; Salgado, HM; Marques, PVS;
Publicação
OPTICS COMMUNICATIONS
Abstract
A full characterization of reversible long-period fibre gratings produced through the wind of a string around a fibre/grooved tube set is presented. This technique enables a good control over the gratings isolation loss-peaks and has high repeatability. The tunability of the resonant wavelengths through the etching of the fibres cladding, prior to perform the gratings, have been investigated. These mechanically induced long-period fibre gratings have shown high sensitivity to loads.
2003
Autores
Pires, EJS; Machado, JAT; Oliveira, PBD;
Publicação
PROCEEDINGS OF THE 11TH INTERNATIONAL CONFERENCE ON ADVANCED ROBOTICS 2003, VOL 1-3
Abstract
This work addresses the fractional-order dynamics during the evolution of a Genetic Algorithm population (GA) for generating a robot manipulator trajectory. The GA objective is to minimize the trajectory space/time ripple without exceeding the torque requirements. In order to investigate the phenomena involved in the GA population evolution, the mutation is exposed to excitation perturbations and the corresponding fitness variations are evaluated. The input/output signals are studied revealing a fractional-order dynamic evolution, characteristic of a long-term system memory.
2003
Autores
Santos, MMD; Vasques, F; Stemmer, MR;
Publicação
Acta Scientiarum. Technology - Acta Sci. Technol.
Abstract
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