2003
Authors
Ferreira, NMF; Machado, JAT;
Publication
PROCEEDINGS OF THE 11TH INTERNATIONAL CONFERENCE ON ADVANCED ROBOTICS 2003, VOL 1-3
Abstract
This paper presents the implementation of fractional-order algorithms in the position/force hybrid control of robotic manipulators. The system performance and robustness is analyzed in the time and frequency domains. The effect of dynamic backlash and flexibility is also investigated.
2003
Authors
Fernandes, PA; Carvalho, ATP; Marques, AT; Pereira, ALF; Madeira, APS; Ribeiro, ASP; Carvalho, AFR; Ricardo, ETA; Pinto, FJV; Santos, HA; Mangericao, HDG; Martins, HM; Pinto, HDB; Santos, HRR; Moreira, IS; Azeredo, MJV; Abreu, RPS; Oliveira, RMS; Sousa, SFM; Silva, RJAM; Mourao, ZS; Ramos, MJ;
Publication
JOURNAL OF COMPUTER-AIDED MOLECULAR DESIGN
Abstract
New designs for Magnetic Resonance Imaging contrast agents are presented. Essentially, they all are host-guest inclusion complexes between. gamma-cyclodextrins and polyazamacrocycles of gadolinium (III) ion. Substitutions have been made to the host to optimise the host-guest association. Molecular mechanics calculations have been performed, using the UFF force field for metals, to decide on the suitability of the substitutions, and to evaluate the host-guest energies of association. Interesting general conclusions have been obtained, concerning the improvement of Magnetic Resonance Imaging contrast agents; namely, a set of rational methodologies have been deduced to improve the association between the gadolinium (III) chelates and the cyclodextrins, and their efficiency is demonstrated with a large set of substituted complexes, opening new doors to increase the diagnostic capabilities of Magnetic Resonance Imaging.
2003
Authors
Frazao, O; Terroso, I; Carvalho, JP; Salgado, HM;
Publication
OPTICS COMMUNICATIONS
Abstract
We propose and demonstrate an architecture of a 2 x 2 port optical cross-connect (OXC) using tuneable fibre Bragg gratings and optical circulators. The proposed OXC is scalable to N x N ports owing to the cascadability of individual routing modules, which perform routing of specific wavelength channels. The performance of the cross-connect is also experimentally evaluated.
2003
Authors
Cunha, JPS; Vollmar, C; Li, ZJ; Fernandes, J; Feddersen, B; Noachtar, S;
Publication
EPILEPSIA
Abstract
2003
Authors
Melo, M; Frazao, O; Teixeira, ALJ; Gomes, LA; da Rocha, JRF; Salgado, HM;
Publication
APPLIED PHYSICS B-LASERS AND OPTICS
Abstract
In this paper, we present a continuous-wave tunable fibre ring laser operating in the L-band. A bi-directional pumped L-band erbium-doped fibre amplifier provides gain to the loop. Tunability is achieved by bending a single-mode fibre taper using a micrometer drive, controlling in this way the spectral cavity losses. Laser emission is achieved between 1587 and 1606 nm, and low variation of the output laser power is observed over all the tuning range.
2003
Authors
Carvalho, J; Portugal, P; Carvalho, A;
Publication
2003 IEEE INTERNATIONAL SYMPOSIUM ON INDUSTRIAL ELECTRONICS, VOLS 1 AND 2
Abstract
Fieldbus networks have been assuming a high acceptance in the industrial environment, replacing the old centralized control architectures. Due to time critical nature of the tasks involved in these environments, the fulfillment of dependability attributes is usually required. Therefore the dependability is an important parameter on system design, which should be evaluated. Several factors can affect system dependability. The environmental ones are the most common and due to the particularity of the industrial environment this susceptibility is increased. In this paper it is proposed a framework based on fault injection techniques, supported by a hardware platform which emulates a fault set, representative of industrial environment scenarios, intending to disturb data communications on a PROFIBUS network. From these fault injection experiments, relevant data is gathered and a further analysis is carried out to evaluate dependability attributes.
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