2013
Authors
Monteiro, C; Ramirez Rosado, IJ; Alfredo Fernandez Jimenez, LA;
Publication
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.
2013
Authors
Sousa, JC; Kokkinogenis, Z; Rossetti, RJF; Saraiva, JT;
Publication
1st International Workshop on Simulation for Energy, Sustainable Development and Environment, SESDE 2013, Held at the International Multidisciplinary Modeling and Simulation Multiconference, I3M 2013
Abstract
The emergence of electricity markets and the opportunities consequently created have radically modified the operation planning activities of Power Systems. As direct result, there is the need for developing new methods to meet in an efficient way the requirements of generation companies, so to respond adequately to new challenges such as market competition. Agent-based models have been proposed in the literature as surrogate to equilibrium models when the problem is too complex to be addressed within a traditional equilibrium framework. Driven by this trend, this paper discusses and proposes a conceptual model following the agent paradigm that deals with the inherent complexity of electricity markets. The devised model proved to be robust enough to represent key features of our study domain and is ready to be actually developed in a computational tool to help generation companies to build their short-medium term operation decisions in a more sounded and robust way.
2013
Authors
Costa, L; Pereira, C; Sousa, C;
Publication
Atas da 13ª Conferência da Associação Portuguesa de Sistemas de Informação
Abstract
2013
Authors
Felipe, RG; Serodio, H; Silva, JP;
Publication
PHYSICAL REVIEW D
Abstract
We study neutrino masses and mixing in the context of flavor models with A(4) symmetry, three scalar doublets in the triplet representation, and three lepton families. We show that there is no representation assignment that yields a dimension-5 mass operator consistent with experiment. We then consider a type-I seesaw with three heavy right-handed neutrinos, explaining in detail why it fails, and allowing us to show that agreement with the present neutrino oscillation data can be recovered with the inclusion of dimension-3 heavy neutrino mass terms that break softly the A(4) symmetry.
2013
Authors
Proença, J; Clarke, D;
Publication
COORDINATION
Abstract
Interaction constraints are an expressive formalism for describing coordination patterns, such as those underlying the coordination language Reo, that can be efficiently implemented using constraint satisfaction technologies such as SAT and SMT solvers. Existing implementations of interaction constraints interact with external components only in a very simple way: interaction occurs only between rounds of constraint satisfaction. What is missing is any means for the constraint solver to interact with the external world during constraint satisfaction. This paper introduces interactive interaction constraints which enable interaction during constraint satisfaction, and in turn increase the expressiveness of coordination languages based on interaction constraints by allowing a larger class of operations to be considered to occur atomically. We describe how interactive interaction constraints are implemented and detail a number of strategies for guiding constraint solvers. The benefit of interactive interaction constraints is illustrated using two examples, a hotel booking system and a system of transactions with compensations. From a general perspective, our work describes how to open up and exploit constraint solvers as the basis of a coordination engine. © 2013 IFIP International Federation for Information Processing.
2013
Authors
Faria, BM; Reis, LP; Lau, N;
Publication
PROCEEDINGS OF THE 2013 13TH INTERNATIONAL CONFERENCE ON AUTONOMOUS ROBOT SYSTEMS (ROBOTICA)
Abstract
The development of an intelligent wheelchair (IW) platform that may be easily adapted to any commercial wheelchair and aid any person with special mobility needs is the main objective of this project. To be able to achieve this main objective, three distinct control methods were implemented in the IW: manual, shared and automatic. Several manual, shared and automatic control algorithms were developed for this task. This paper presents three of the most significant of those algorithms with emphasis on the shared control method. Experiments were performed, using a realistic simulator, with real users suffering from cerebral palsy in order to validate the approach. These experiments enabled to conclude which were the best shared control methods to implement on the IW. The experiments also revealed the importance of using shared (aided) controls for users with severe disabilities. The patients still felt having complete control over the wheelchair movement when using a shared control at a 50% level and thus this control type was very well accepted and should be used in intelligent wheelchairs since it is able to correct the direction in case of involuntary movements of the user but still gives him a sense of complete control over the IW movement.
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