2014
Authors
Strecht, P; Mendes Moreira, J; Soares, C;
Publication
ADVANCED DATA MINING AND APPLICATIONS, ADMA 2014
Abstract
Predicting the failure of students in university courses can provide useful information for course and programme managers as well as to explain the drop out phenomenon. While it is important to have models at course level, their number makes it hard to extract knowledge that can be useful at the university level. Therefore, to support decision making at this level, it is important to generalize the knowledge contained in those models. We propose an approach to group and merge interpretable models in order to replace them with more general ones without compromising the quality of predictive performance. We evaluate our approach using data from the U. Porto. The results obtained are promising, although they suggest alternative approaches to the problem.
2014
Authors
Teixeira, AC; Barros, MJ;
Publication
Local Economy
Abstract
Despite extensive research on decentralisation, the role of local governments in promoting the internationalisation of firms has been rather neglected in the literature. Based on a sample of 144 Portuguese municipalities, and resorting to logistic econometric estimations, we found that: (1) the majority of municipalities have been involved in activities to promote economic development and the internationalisation of firms; (2) municipalities are essentially involved in the branding of regions (image building) or in organising fairs and trade missions and (3) municipalities more active in promoting the internationalisation of small and medium-sized enterprises (SMEs) tend to be more peripheral, with a relatively high area and population density, higher purchasing power, higher proportion of population with secondary schooling, lower density entrepreneurial context but with higher amounts of exports. Although there is still a long way to go for a more profound and comprehensive decentralisation at this level in Portugal, given the knowledge municipalities possess about the firms that are located in their vicinity, we contend that it would be desirable that more decentralised efforts be put towards the implementation of information, and education/training-related programmes aiming at promoting SMEs internationalisation. © The Author(s) 2014.
2014
Authors
Campos, DM; Simoes, A; Ramos, I; Campilho, A;
Publication
IFMBE Proceedings
Abstract
Lung nodule segmentation allows for automatic measurement of the nodule's size or volume which is of utmost importance in lung cancer diagnosis. It is a challenging task since there are many different types of nodules (solid or non-solid, solitary or multiple, etc). A supervised lung nodule segmentation method uses a shape-based, contrast-based and intensity-based feature set to produce three preliminary segmentations and an artificial neural network to obtain a more accurate segmentation. This method was applied to 20 computer tomography studies, all containing nodules. The data has 10 images of solid nodules and 10 images of ground glass opacity nodules, all with ground-truth. The segmentation uses a region growing approach and the volumetric shape index is used for nodule detection and providing a seed point. In the first and second segmentation the probability of each neighbor belonging to the nodule is estimated using the volumetric shape index and the convergence index filter, respectively. The third segmentation is obtained using a feature set region regression method where for each neighbor the probability of belonging to the nodule or not is obtained using k nearest neighbor regression. Then, using a leave-one out method, an artificial neural network uses the three preliminary segmentations as input and is trained to obtain a more accurate segmentation. Results obtained a 12% relative volume error, 88% and 93% Jaccard and Dice coefficient respectively. © 2014, Springer International Publishing Switzerland.
2014
Authors
Pacheco, AP; Claro, J; Oliveira, T;
Publication
Advances in forest fire research
Abstract
2014
Authors
Pereira, P; Leitao, S; Solteiro Pires, EJS;
Publication
2014 SIXTH WORLD CONGRESS ON NATURE AND BIOLOGICALLY INSPIRED COMPUTING (NABIC)
Abstract
The paper presents a study about optimal supply of the energy service, using simulations of network operation scenarios, in order to optimize resources and minimize the variables: operation cost, energy losses, generation cost and consumers shedding. These simulations create optimal operation models of the network, allowing the system operator obtain knowledge to take pre-established procedures that must be performed in situations of contingency in order to forecast and minimize drawbacks. The simulations were performed using a multiobjective particle swarm optimization algorithm. The algorithm was applied to the IEEE 14 Bus network where the optimal power flow was evaluated by the MATPOWER tool to establish an optimal electrical working model to minimize the associated costs.
2014
Authors
Zhang, SH; Li, X; Blanton, RD; da Silva, JM; Carulli, JM; Butler, KM;
Publication
2014 IEEE INTERNATIONAL TEST CONFERENCE (ITC)
Abstract
In this paper, a novel Bayesian model fusion (BMF) method is proposed for test cost reduction based on wafer-level spatial variation modeling. BMF relies on the assumption that a large number of wafers of the same circuit design (e.g., all wafers from the same lot) share a similar spatial pattern. Hence, the measurement data from one wafer can be borrowed to model the spatial variation of other wafers via Bayesian inference. By applying the Sherman-Morrison-Woodbury formula, a fast numerical algorithm is derived to reduce the computational cost of BMF for practical test applications. Furthermore, a new test methodology is developed based on BMF and it closely monitors the escape rate and yield loss. As is demonstrated by the wafer probe measurement data of an industrial RF transceiver, BMF achieves 1.125x reduction in test cost and 2.6x reduction in yield loss, compared to the conventional approach based on virtual probe (VP).
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