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Publicações

Publicações por CPES

2010

USING INFORMATION TECHNOLOGY BASED EXERCISES IN PRIMARY MATHEMATICS TEACHING OF CHILDREN WITH CEREBRAL PALSY AND MENTAL RETARDATION: A CASE STUDY

Autores
Reis, MGAD; Cabral, L; Peres, E; Bessa, M; Valente, A; Morais, R; Soares, S; Baptista, J; Aires, A; Escola, JJ; Bulas Cruz, JA; Reis, MJCS;

Publicação
TURKISH ONLINE JOURNAL OF EDUCATIONAL TECHNOLOGY

Abstract
Technology has profoundly changed the way we learn and live. Indeed, such relationship appears to be quite complex, within IT contexts, and especially in socially and technologically rich learning environments, where related skills and learning are progressively required and fostered. Thus, if a satisfactory level of intellectual performance and social competence of a primary school pupil is indeed highly dependent on the type of participation that parents offer their children, IT, in general, and Internet, in particular, may well provide a new paradigm, setting forth that education and communication approach is truly more complex than ever before. It is on the basis of such paradigm that we therefore present a case study where a set of multimedia exercises were used in order to possibly improve the mathematical skills of pupils, one with mental retardation and another with cerebral palsy. Being part of a Web-based system to support students' learning, the referred set of multimedia exercises proved to be the children's favorite, rather than exercises in paper form, which also led the children to show a fair more positive attitude towards learning. Also, we observed that through the mentioned multimedia exercises, the children became far more autonomous, interested, persistent, happy, and able to easily absorb the material as well as more willingly to continue on working.

2010

Time Domain BRS Estimation: Least Squares versus Quantile Regression

Autores
Gouveia, S; Rocha, C; Rocha, AP; Silva, ME;

Publicação
COMPUTING IN CARDIOLOGY 2010, VOL 37

Abstract
The BRS can be quantified as the slope between SBP and RR values identified in baroreflex events, estimated by ordinary least squares (OLS) minimization. Quantile regression (QR) is a more robust procedure than OLS and allows a more complete characterization of the data, by estimating conditional functions for different quantiles of interest. In this work, OLS and QR for BRS estimation are compared regarding slope estimates and dispersion. The EuroBaVar results indicate that OLS slope and QR slopes at different quantiles do not exhibit significant differences. Also, OLS and QR slopes require similar number of beats to achieve a given BRS precision in stationary recordings. Finally, BRS estimated with OLS exhibit relative dispersion lower than 10% and 5% when computed from stationary recordings of approximately 3 and 9 minutes length, respectively.

2010

Electricity market equilibrium based on conjectural variations

Autores
Diaz, CA; Villar, J; Alberto Campos, FA; Reneses, J;

Publicação
ELECTRIC POWER SYSTEMS RESEARCH

Abstract
Many of the models used for the representation of the generation companies' behavior in oligopolistic electricity markets are based on conjectural variation equilibria, which are a generalization of the classic Cournot approach. However, one of the main drawbacks of these approaches is the complexity of assigning adequate values to the conjectures, which can dramatically affect the results obtained from these models. This paper reviews and analyses the main formulations of conjectural equilibria applied to electricity markets. The paper shows how these different formulations are equivalent, and presents the relationships among the conjectures they use. Finally, it presents a brief overview on the main methods to estimate or compute the conjectures of these types of models.

2010

MORSE: Tools for long-term strategic analysis of the Spanish electricity sector

Autores
Villar, J; Campos, FA; Díaz, CA; González, J; Diaz, A; Rodriguez, MA; Rodriguez, P;

Publicação
2010 7th International Conference on the European Energy Market, EEM 2010

Abstract
MORSE is a set of tools developed for the Spanish electrical utility Endesa, for long term simulation and strategic analysis of the Spanish electricity sector. MORSE has three different types of modules: forecasting modules, to model the main businesses of the sector, data preparation modules, to define the sector structure, to import data from other Endesa planning tools and to prepare it for the forecasting modules, and analysis and reports modules, to prepare simulation scenarios to be feed to the forecasting modules, execute them, and collect and organize their outputs in appropriate reports. The pool simulation model of the system, EQUITEC, is a Conjectured Supply Function Equilibrium, where generation companies are represented at a technology level, and conjectures are endogenously computed under hypothesis of local linearity near the equilibrium point. The inclusion in EQUITEC of network and zonal constraints is currently being analyzed. © 2010 IEEE.

2010

Solving Cournot equilibriums with variational inequalities algorithms

Autores
Campos, FA; Villar, J; Barquin, J;

Publicação
IET GENERATION TRANSMISSION & DISTRIBUTION

Abstract
Over the past two decades, the fact that many games have been formulated as variational inequalities problems has led to relevant developments related with the existence and uniqueness of equilibriums, and with their calculation methodologies. Based on this approach, this study applies sufficient conditions for Cournot equilibriums existence and uniqueness, proving that while existence holds, uniqueness cannot be proved in general. To find one of the existent equilibriums, this study also proposes a novel variational inequalities algorithm which is globally convergent and easy to implement. It iteratively computes searching directions of the equilibrium by generating hyper-planes that separate the equilibrium from the intermediate solutions obtained relaxing the original Cournot game. Unlike other related algorithms, the proposed algorithm does not require Jacobian matrixes evaluation, and the iterative relaxed games can easily be solved using convex and quadratic optimisation models. Numerical results show the operation and convergence of the algorithm.

2010

Energy decomposition analysis of cis and trans isomers of 1,2-dihaloethylenes and 2-butene

Autores
Mourao, ZS; Melo, A;

Publicação
JOURNAL OF MOLECULAR STRUCTURE-THEOCHEM

Abstract
Mayer's energy decomposition method was applied inthe study of the relative stability of cis and trans isomers of 1,2-disubstituted ethylenes, XHC=CHX (X = F, Cl, Br) and 2-butene. The trans to cis isomerization energy for each system was determined at the Hartree-Fock level, with several basis sets, and then divided into monoatomic and diatomic energy contributions. The results point to a different energy distribution for the dihaloethylenes, known for exhibiting a cis isomer that is more stable than the trans one, a behavior that is known as the cis effect, when compared to 2-butene. The main stabilizing effects of the cis isomer in the dihaloethylenes, at this level of theory, are energy terms associated with the interaction of the X substituents with the C atoms.

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