2013
Autores
Fernandes, P; Pereira, C; Barbosa, A;
Publicação
Atas da 13ª Conferência da Associação Portuguesa de Sistemas de Informação
Abstract
2013
Autores
Silva, A; Sobocinski, P;
Publicação
Bulletin of the EATCS
Abstract
2013
Autores
Alves, F; Pereira, C; Sousa, C;
Publicação
Atas da 13ª Conferência da Associação Portuguesa de Sistemas de Informação
Abstract
2013
Autores
Marques, L; Vasconcelos, V; Pedreiras, P; Almeida, L;
Publicação
Proceedings of 2013 IEEE 18th Conference on Emerging Technologies & Factory Automation, ETFA 2013, Cagliari, Italy, September 10-13, 2013
Abstract
Distributed Embedded Systems are subject to transient communication faults that need being detected and mitigated in safety-critical scopes. This paper addresses error recovery in time-triggered systems based on the Controller Area Network (CAN). It extends a recent work that proposed using online traffic scheduling, combined with servers, to implement dynamic message retransmissions. In particular, we provide a schedulability analysis that considers the interference of the error-recovery server in the time-triggered traffic, as well as a methodology to compute the worst-case response time of messages affected by errors. We also present a comparison with related error-recovery methods that confirms the superiority of the proposed method. © 2013 IEEE.
2013
Autores
Barroso, AC; Silva, JP;
Publicação
AMERICAN JOURNAL OF PHYSICS
Abstract
We consider a current-carrying wire loop made out of linear segments of arbitrary sizes and directions in three-dimensional space. We develop expressions to calculate its vector potential and magnetic field at all points in space. We then calculate the mutual inductance between two such (non-intersecting) piecewise-linear loops. As simple applications, we consider in detail the mutual inductance between two square wires of equal length that either lie in the same plane or lie in parallel horizontal planes with their centers on the same vertical axis. Our expressions can also be used to obtain approximations to the mutual inductance between wires of arbitrary three-dimensional shapes. (C) 2013 American Association of Physics Teachers.
2013
Autores
Monteiro, C; Ramirez Rosado, IJ; Alfredo Fernandez Jimenez, LA;
Publicação
RENEWABLE ENERGY
Abstract
This paper presents an original short-term forecasting model for hourly average electric power production of small-hydro power plants (SHPPs). The model consists of three modules: the first one gives an estimation of the "daily average" power production; the second one provides the final forecast of the hourly average power production taking into account operation strategies of the SHPPs; and the third one allows a dynamic adjustment of the first module estimation by assimilating recent historical production data. The model uses, as inputs, forecasted precipitation values from Numerical Weather Prediction tools and past recorded values of hourly electric power production in the SHPPs. The structure of the model avoids crossed-influences between the adjustments of such model due to meteorological effects and those due to the operation strategies of the SHPPs. The forecast horizon of the proposed model is seven days. which allows the use of the final forecast of the power production in Power System operations, in electricity markets, and in maintenance scheduling of SHPPs. The model has been applied in the forecasting of the aggregated hourly average power production for a real-life set of 130 SHPPs in Portugal achieving satisfactory results, maintaining the forecasting errors delimited in a narrow band with low values.
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