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Publications

2016

Pollen-based predictive modelling of wine production: application to an arid region

Authors
Cunha, M; Ribeiro, H; Abreu, I;

Publication
EUROPEAN JOURNAL OF AGRONOMY

Abstract
A wine forecast model for one of the most arid wine regions of the Europe-Alentejo was improved and tested for the period 1998-2014. During this period, Alentejo region had strong upward trends in wine production associated to the increase of vineyard area. The forecast model was supported on a hierarchical analysis, including the determination of the potential production at flowering by quantifying airborne pollen concentration, followed by a climate based evaluation of the possible impact of fruit-set conditions in the limitation of production. Through the monitoring of airborne pollen flows it is possible to define an accurate main pollen season and determine the regional pollen index that will be used as independent variable in the regional forecast model. The time trend, which was initially removed from data, was then added back to obtain the forecast. Stepwise regression and cross-validation were employed during the period 1998-2014 for calibration of the model used for predicting annual wine production. The developed model explained about 86% of wine variance over the years with absolute average error of 6% for the cross validation and 87% of cases had differences between actual and forecasted wine production below 10%. The reliability and early-indication ability of the proposed forecast model justify their use to respond to a number of government agencies and wine industry concerns and activities.

2016

A gestão da informação nas universidades públicas portuguesas. Reequacionamento e proposta de modelo

Authors
Maria Manuela Gomes de Azevedo Pinto;

Publication

Abstract

2016

Conchord: An Application for Generating Musical Harmony by Navigating in the Tonal Interval Space

Authors
Bernardes, G; Cocharro, D; Guedes, C; Davies, MEP;

Publication
Music, Mind, and Embodiment

Abstract
We present Conchord, a system for real-time automatic generation of musical harmony through navigation in a novel 12-dimensional Tonal Interval Space. In this tonal space, angular and Euclidean distances among vectors representing multi-level pitch configurations equate with music theory principles, and vector norms acts as an indicator of consonance. Building upon these attributes, users can intuitively and dynamically define a collection of chords based on their relation to a tonal center (or key) and their consonance level. Furthermore, two algorithmic strategies grounded in principles from function and root-motion harmonic theories allow the generation of chord progressions characteristic of Western tonal music.

2016

A neural network to classify fatigue from human-computer interaction

Authors
Pimenta, A; Carneiro, D; Neves, J; Novais, P;

Publication
NEUROCOMPUTING

Abstract
Fatigue, especially in its mental form, is one of the most worrying health problems nowadays. It affects not only health but also motivation, emotions and feelings and has an impact both at the individual and organizational level. Fatigue monitoring and management assumes thus, in this century, an increased importance, that should be promoted by private organizations and governments alike. While traditional approaches are mostly based on questionnaires, in this paper we present an alternative one that relies on the observation of the individual's interaction with the computer. We show that this interaction changes with the onset of fatigue and that these changes are significant enough to support the training of a neural network that can classify mental fatigue in real time. The main outcome of this work is the development of non-invasive systems for the continuous classification of mental fatigue that can support effective and efficient fatigue management initiatives, especially in the context of desk jobs.

2016

Metalearning to support competitive electricity market players' strategic bidding

Authors
Pinto, T; Sousa, TM; Morais, H; Praca, I; Vale, Z;

Publication
ELECTRIC POWER SYSTEMS RESEARCH

Abstract
Electricity markets are becoming more competitive, to some extent due to the increasing number of players that have moved from other sectors to the power industry. This is essentially resulting from incentives provided to distributed generation. Relevant changes in this domain are still occurring, such as the extension of national and regional markets to continental scales. Decision support tools have thereby become essential to help electricity market players in their negotiation process. This paper presents a metalearner to support electricity market players in bidding definition. The proposed metalearner uses a dynamic artificial neural network to create its own output, taking advantage on several learning algorithms already implemented in ALBidS (Adaptive Learning strategic Bidding System). The proposed metalearner considers different weights for each strategy, based on their individual performance. The metalearner's performance is analysed in scenarios based on real electricity markets data using MASCEM (Multi-Agent Simulator for Competitive Electricity Markets). Results show that the proposed metalearner is able to provide higher profits to market players when compared to other current methodologies and that results improve over time, as consequence of its learning process.

2016

Analysis of market quality before and during short-selling bans

Authors
Alves, C; Mendes, V; da Silva, PP;

Publication
RESEARCH IN INTERNATIONAL BUSINESS AND FINANCE

Abstract
We measure the impact of the August 2011 bans on covered short-selling adopted by several European countries. Our results provide evidence that the impact on prices was shortlived: the positive price impact disappears after ten days. The short-selling restrictions did not contribute to reduce the volatility of the financial stocks subjected to the bans; on the contrary, our findings indicate that volatility actually increased by a greater extent for these stocks than for other financial stocks with similar characteristics. The bans also had a negative impact on liquidity. Moreover, stocks subjected to the bans exhibit a longer delay in the assimilation of negative market news during the banning span.

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