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Publications

2015

Lithium batteries temperature and strain fiber monitoring

Authors
Nascimento, M; Novais, S; Leitao, C; Fatima Domingues, MF; Alberto, N; Antunes, P; Pinto, JL;

Publication
24TH INTERNATIONAL CONFERENCE ON OPTICAL FIBRE SENSORS

Abstract
Fiber Bragg grating sensors were attached to the surface of a rechargeable lithium battery in order to monitor its thermal and strain fluctuations through charge and different discharge C rates. During the discharge process above 1C, it were observed, a temperature and strain fluctuations of a 4.12 +/- 0.67 degrees C and 24.64 +/- 6.02 mu epsilon, respectively. In the regular charge process, a temperature and strain variation of 1.03 +/- 0.67 degrees C and 15.86 +/- 6.02 mu epsilon, were detected.

2015

STUDY OF THE PORTUGUESE POPULATIONS OF POWDERY MILDEW FUNGUS FROM DIVERSE GRAPEVINE CULTIVARS (VITIS VINIFERA)

Authors
Oliveira, M; Cunha, M;

Publication
JOURNAL INTERNATIONAL DES SCIENCES DE LA VIGNE ET DU VIN

Abstract
Aims: The main goal of this work was to describe the genetic diversity and population structure of Portuguese isolates from Erysiphe necator using a new approach for the sampling of DNA from this pathogen. Methods and results: The present study was conducted in the main demarcated wine regions of Portugal, where leaf and berry samples were collected for further genetic analysis. After DNA extraction, the Internal Transcribed Spacer from the 18S ribosomal RNA (ITS), the Intergenic Spacer (IGS), and the beta-tubulin gene were successfully amplified and sequenced. The populations of E. necator are structured into two genetically distinct groups (A and B), with the majority of the analyzed samples belonging to group B. Conclusion: Regardless of its geographical origin and the Vitis vinifera cultivar, the population of E. necator presents low genetic diversity. Significance and impact of the study: The present work will certainly help to increase the vineyard productivity through a better definition of preventive measures and a potential decrease in the direct and indirect costs associated with the use of fungicides.

2015

Density-based graph model summarization: Attaining better performance and efficiency

Authors
Valizadeh, M; Brazdil, P;

Publication
INTELLIGENT DATA ANALYSIS

Abstract
Several algorithms based on PageRank algorithm have been proposed to rank the document sentences in the multi-document summarization field and LexRank and T-LexRank algorithms are well known examples. In literature different concepts such as weighted inter-cluster edge, cluster-sensitive graph model and document-sensitive graph model have been proposed to improve LexRank and T-LexRank algorithms (e.g. DsR-G, DsR-Q) for multi-document summarization. In this paper, a density-based graph model for multi-document summarization is proposed by adding the concept of density to LexRank and T-LexRank algorithms. The resulting generic multi-document summarization systems, DensGS and DensGSD were evaluated on DUC 2004 while the query-based variants, DensQS, DensQSD were evaluated on DUC 2006, DUC 2007 and TAC 2010 task A. ROUGE measure was used in the evaluation. Experimental results show that density concept improves LexRank and T-LexRank algorithms and outperforms previous graph-based models (DsR-G and DsR-Q) in generic and query-based multi-document summarization tasks. Furthermore, the comparison of the number of iterations indicates that the density-based algorithm is faster than the other algorithms based on PageRank.

2015

The importance of non-financial determinants on public-private partnerships in Europe

Authors
Mota, J; Moreira, AC;

Publication
INTERNATIONAL JOURNAL OF PROJECT MANAGEMENT

Abstract
In previous work regarding public-private partnership (PPP) arrangements the theoretical rationales and empirical results have mainly focused on analyzing the importance of quantitative features related to budget constraints deriving from public deficits, the existence of an infrastructure gap and the efficiency hypothesis. Thus, this study aims to identify the underlying determinants behind the proliferation and execution of PPPs, emphasizing the importance that non-financial (such as political, legal and macroeconomic) determinants have in establishing a PPP, as well as the factors that enhance the attractiveness of a country to encourage the private sector through PPPs in the European context. The results of this study show that the macroeconomic environment represented by economic freedom, competitiveness and the unemployment rate is essential for PPPs, as well as the legal system, where regulatory quality and effective rule of law are associated with the effective execution of a PPP. The political environment and previous experience of PPPs are also key factors in making a country more attractive for establishing PPPs.

2015

A biased random-key genetic algorithm for the unequal area facility layout problem

Authors
Goncalves, JF; Resende, MGC;

Publication
EUROPEAN JOURNAL OF OPERATIONAL RESEARCH

Abstract
This paper presents a biased random-key genetic algorithm (BRKGA) for the unequal area facility layout problem (UA-FLP) where a set of rectangular facilities with given area requirements has to be placed, without overlapping, on a rectangular floor space. The objective is to find the location and the dimensions of the facilities such that the sum of the weighted distances between the centroids of the facilities is minimized. A hybrid approach combining a BRKGA, to determine the order of placement and the dimensions of each facility, a novel placement strategy, to position each facility, and a linear programming model, to fine-tune the solutions, is developed. The proposed approach is tested on 100 random datasets and 28 of benchmark datasets taken from the literature and compared with 21 other benchmark approaches. The quality of the approach was validated by the improvement of the best known solutions for 19 of the 28 extensively studied benchmark datasets.

2015

A comparative study of vineyard phenology and pollen metrics extracted from airborne pollen time series

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

Publication
AEROBIOLOGIA

Abstract
Airborne pollen emission model was used to determine pollen metrics and to examine their relationship with vineyard phenology in two wine regions of Northern Portugal: Vinhos Verdes (1993-2007) and Douro (1992-2011). A number of airborne pollen metrics were obtained through the rate of changes of logistic model adjusted to the time series of airborne pollen. In both regions, the mean absolute differences between observed phenology and model-predicted values for start, peak and final of flowering phenophases were always lower than 5 days and the slope of the regression through the origin is close to one. These metrics can be used to accurately and precisely predict the dynamic of Vitis flowering observed at field level. The model's simplicity and flexibility are of great advantage for its practical use in aerobiology.

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