2011
Autores
Pousinho, HMI; Mendes, VMF; Catalao, JPS;
Publicação
ENERGY CONVERSION AND MANAGEMENT
Abstract
The increased integration of wind power into the electric grid, as nowadays occurs in Portugal, poses new challenges due to its intermittency and volatility. Wind power prediction plays a key role in tackling these challenges. The contribution of this paper is to propose a new hybrid approach, combining particle swarm optimization and adaptive-network-based fuzzy inference system, for short-term wind power prediction in Portugal. Significant improvements regarding forecasting accuracy are attainable using the proposed approach, in comparison with the results obtained with five other approaches.
2011
Autores
Alves, S; Fernandez, M; Florido, M; Mackie, I;
Publicação
PPDP 11 - PROCEEDINGS OF THE 2011 SYMPOSIUM ON PRINCIPLES AND PRACTICES OF DECLARATIVE PROGRAMMING
Abstract
We show that the full PCF language can be encoded in L-rec, a syntactically linear lambda-calculus extended with numbers, pairs, and an unbounded recursor that preserves the syntactic linearity of the calculus. We give call-by-name and call-by-value evaluation strategies and discuss implementation techniques for L-rec, exploiting its linearity.
2011
Autores
Bento, VF; Cruz, VT; Ribeiro, DD; Cunha, JPS;
Publicação
2011 ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY (EMBC)
Abstract
The paper proposes an integrated system to automatically assess motor function after neurological injury. A portable motion capture system was developed in order to obtain all the relevant three dimensional kinematics of the upper limb movement. These kinematics were analyzed by means of a decision tree classifier which features where inferred from the Functional Ability Score (FAS) of the Wolf Motor Function Test (WMFT). In addition, the system is able to correctly quantify the performance time of each selected task of the WMFT. In terms of the FAS the system and the clinician show coherent results for 3 out of 5 patients in the first task tested and 4 out of 5 for the second task tested. Regarding performance time, the mean error between the system and the clinician was of 0.216 s for the 25 trials performed (5 patients, 5 tasks each). These results represent an important proof of concept towards a system capable of precisely evaluate upper limb motor function after neurological injury.
2011
Autores
Lopes, AM; Pires, EJS;
Publicação
NONLINEAR SCIENCE AND COMPLEXITY
Abstract
Dynamic modeling is of great importance regarding computer simulation and advanced control of parallel manipulators. Dynamic modeling of parallel manipulators presents an inherent complexity, mainly due to system closed-loop structure and kinematic constraints. In this paper an approach based on the manipulator generalized momentum is explored and applied to the dynamic modeling of a Stewart platform. The generalized momentum is used to compute the kinetic component of the generalized force acting on each manipulator rigid body. Analytic expressions for the rigid bodies' inertia and Coriolis and centripetal terms matrices are obtained, which can be added, as they are expressed in the same frame. Gravitational part of the generalized force is obtained using the manipulator potential energy.
2011
Autores
Banik, N; Ferreira, FA; Martins, J; Pinto, AA;
Publicação
DYNAMICS, GAMES AND SCIENCE II
Abstract
We consider an international trade economical model where two firms of different countries compete in quantities and can use three different strategies: (i) repealed collusion, (ii) deviation from the foreigner firm followed by punishment by he home country and then followed by repeated Cournot, or (iii) repeated deviation followed by punishment. In some cases (ii) and (iii) can be interpreted as dumping, We compute the profits of both firms for each strategy and we characterize the econc,mical parameters where each strategy is adopted by the firms.
2011
Autores
Aprile, E; Angle, J; Arneodo, F; Baudis, L; Bernstein, A; Bolozdynya, A; Brusov, P; Coelho, LCC; Dahl, CE; DeViveiros, L; Ferella, AD; Fernandes, LMP; Fiorucci, S; Gaitskell, RJ; Giboni, KL; Gomez, R; Hasty, R; Kastens, L; Kwong, J; Lopes, JAM; Madden, N; Manalaysay, A; Manzur, A; McKinsey, DN; Monzani, ME; Ni, K; Oberlack, U; Orboeck, J; Orlandi, D; Plante, G; Santorelli, R; dos Santos, JMF; Shagin, P; Shutt, T; Sorensen, P; Schulte, S; Tatananni, E; Winant, C; Yamashita, M;
Publicação
ASTROPARTICLE PHYSICS
Abstract
XENON10 is the first two-phase xenon time projection chamber (TPC) developed within the XENON dark matter search program. The TPC, with an active liquid xenon (LXe) mass of about 14 kg, was installed at the Gran Sasso Underground Laboratory (LNGS) in Italy, and operated for more than one year, with excellent stability and performance. Results from a dark matter search with XENON10 have been published elsewhere. In this paper, we summarize the design and performance of the detector and its subsystems, based on calibration data using sources of gamma-rays and neutrons as well as background and Monte Carlo simulation data. The results on the detector's energy threshold, position resolution, and overall efficiency show a performance that exceeds design specifications, in view of the very low energy threshold achieved (< 10 keVr) and low background rate achieved.
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