2017
Autores
Nogueira, MA; Abreu, PH; Martins, P; Machado, P; Duarte, H; Santos, J;
Publicação
BMC MEDICAL IMAGING
Abstract
Background: Positron Emission Tomography - Computed Tomography (PET/CT) imaging is the basis for the evaluation of response-to-treatment of several oncological diseases. In practice, such evaluation is manually performed by specialists, which is rather complex and time-consuming. Evaluation measures have been proposed, but with questionable reliability. The usage of before and after-treatment image descriptors of the lesions for treatment response evaluation is still a territory to be explored. Methods: In this project, Artificial Neural Network approaches were implemented to automatically assess treatment response of patients suffering from neuroendocrine tumors and Hodgkyn lymphoma, based on image features extracted from PET/CT. Results: The results show that the considered set of features allows for the achievement of very high classification performances, especially when data is properly balanced. Conclusions: After synthetic data generation and PCA-based dimensionality reduction to only two components, LVQNN assured classification accuracies of 100%, 100%, 96.3% and 100% regarding the 4 response- to-treatment classes.
2017
Autores
Algarinho, J.; Afonso, Cláudia; Poínhos, Rui; Franchini, Bela; Pinhão, Sílvia; Correia, Flora; Almeida, Maria Daniel Vaz de; Bruno M P M Oliveira;
Publicação
Abstract
2017
Autores
Dias, S; Brito, P;
Publicação
EUROPEAN JOURNAL OF OPERATIONAL RESEARCH
Abstract
We propose a new linear regression model for interval-valued variables. The model uses quantile functions to represent the intervals, thereby considering the distributions within them. In this paper we study the special case where the Uniform distribution is assumed in each observed interval, and we analyze the extension to the Symmetric Triangular distribution. The parameters of the model are obtained solving a constrained quadratic optimization problem that uses the Mallows distance between quantile functions. As in the classical case, a goodness-of-fit measure is deduced. Two applications on up-to-date fields are presented: one predicting duration of unemployment and the other allowing forecasting burned area by forest fires.
2017
Autores
Real, AC; Borges, J; Cabral, JS; Jones, GV;
Publicação
INTERNATIONAL JOURNAL OF CLIMATOLOGY
Abstract
The Douro Valley of Portugal is a well-known wine region producing Port wine since the end of the 18th century, with quality table wines becoming increasingly important over the last 20 years. Port wine production is the most important economic sector of the region and Vintage Port is the top quality Port wine type, produced only from the best vintages. The purpose of this research was to examine how the variability of annual weather influences the quality of Vintage Port. A weather and climate data set for the period 1980-2009 and a consensus ranking that combined a collection of vintage chart scores into a ranking were used to characterize both the weather and the vintage quality. In order to more precisely model the weather influences on the quality of the vintages it was necessary to partition the growing season into smaller growth intervals in which several heat and precipitation variables were evaluated. The heat-related variables were defined according to the phenology of grapevines, using a partition of the growing season based on accumulated temperature, rather than on calendar dates. Precipitation variables were calculated using broad periods corresponding to the dormant, vegetative and maturation stages of the grapevines. A logistic regression model was used as a tool to identify the weather variables that help to explain the relationships between yearly weather characteristics and vintage quality. The results show that several weather characteristics are strongly associated with better quality vintages: growing season mean temperatures above the region's average, warm winters, cool July through veraison and cool temperatures during ripening. In summary, although the weather is not solely responsible for determining a vintage quality, it plays an important role on it; therefore, its understanding can provide invaluable management insights to growers and producers.
2017
Autores
Calabrese, C; Davidson, NR; Fonseca, NA; He, Y; Kahles, A; Lehmann, K; Liu, F; Shiraishi, Y; Soulette, CM; Urban, L; Demircioglu, D; Greger, L; Li, S; Liu, D; Perry, MD; Xiang, L; Zhang, F; Zhang, J; Bailey, P; Erkek, S; Hoadley, KA; Hou, Y; Kilpinen, H; Korbel, JO; Marin, MG; Markowski, J; Nandi, T; Pan-Hammarström, Q; Pedamallu, CS; Siebert, R; Stark, SG; Su, H; Tan, P; Waszak, SM; Yung, C; Zhu, S; Awadalla, P; Creighton, CJ; Meyerson, M; Ouellette, BF; Wu, K; Yang, H; Brazma, A; Brooks, AN; Göke, J; Rätsch, G; Schwarz, RF; Stegle, O; Zhang, Z;
Publicação
Abstract
2017
Autores
Devezas, J; Nunes, S;
Publicação
ERCIM NEWS
Abstract
In an information society, people expect to find answers to their questions quickly and with little effort. Sometimes, these answers are locked within textual documents, which often require a manual analysis, after being retrieved from the web using search engines. At FEUP InfoLab, we are researching graph-based models to index combined data (text and knowledge), with the goal of improving entity-oriented search effectiveness.
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