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Publications

2005

Experimental analysis of outage times for PROFIBUS networks

Authors
Carvalho, JA; Carvalho, AS; Portugal, PJ;

Publication
IECON 2005: THIRTY-FIRST ANNUAL CONFERENCE OF THE IEEE INDUSTRIAL ELECTRONICS SOCIETY, VOLS 1-3

Abstract
Distributed control systems operation strongly depends on the communication system performance. Therefore, their analysis becomes an important aspect to be considered, particularly in situations where communications have real-time constrains and the network operates on faulty environments. In this paper the behavior of PROFIBUS network in the presence of faults is analyzed. This analysis is performed in an experimental base supported by a real network. The network operation is disturbed through a set of fault injection experiments from which performance metrics related with PROFIBUS outage times are evaluated.

2005

Measurement of the salinity in water through long-period gratings arc-induced in pure-silica-core fibers

Authors
Rego G.; Santos J.; Salgado H.;

Publication
Recent Advances in Multidisciplinary Applied Physics

Abstract

2005

Load forecasting performance enhancement when facing anomalous events

Authors
Fidalgo, JN; Lopes, JAP;

Publication
IEEE TRANSACTIONS ON POWER SYSTEMS

Abstract
The application of artificial neural networks or other techniques in load forecasting usually outputs quality results in normal conditions. However, in real-world practice, a remarkable number of abnormalities may arise. Among them, the most common are the historical data bugs (due to SCADA or recording failure), anomalous behavior (like holidays or atypical days), sudden scale or shape changes following switching operations, and consumption habits modifications in the face of energy price amendments. Each of these items is a potential factor of forecasting performance degradation. This paper describes the procedures implemented to avoid the performance degradation under such conditions. The proposed techniques are illustrated with real data examples of current, active, and reactive power forecasting at the primary substation level.

2005

MASTA'05: 3(rd) Workshop on Multi-Agent Systems - Theory and applications

Authors
Balsa, J; Moniz, L; Reis, LP;

Publication
2005 Portuguese Conference on Artificial Intelligence, Proceedings

Abstract

2005

Fast scanning transmissive delay line for multi-scan optical coherence tomography

Authors
Rosa, CC; Rogers, J; Podoleanu, AG;

Publication
Progress in Biomedical Optics and Imaging - Proceedings of SPIE

Abstract
A new transmissive grating-based scanning delay-line for optical coherence tomography is proposed, with dispersion compensation capability. Compared to other spectral delay-lines, our implementation has less loss due to a halved number of diffraction grating reflections, and implements a walk off compensation scheme. The performance of the delay line is evaluated. The delay line transmissive geometry targets balance detection configurations. © 2005 SPIE and OSA.

2005

Approximating optical flow within the MPEG-2 compressed domain

Authors
Coimbra, MT; Davies, M;

Publication
IEEE Transactions on Circuits and Systems for Video Technology

Abstract
MPEG-2 compressed domain information, namely motion vectors and DCT coefficients, is filtered and manipulated to obtain a motion field using a two-dimensional (2-D) translational model. The results are compared to a popular optical flow method, more specifically the one presented by Lucas and Kanade, revealing very good results. Our method provides a very fast motion estimation tool that can be useful for applications where algorithmic cost is critical, such as surveillance systems. All methods are theoretically explained and their efficiency confirmed on real-world data.

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