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Publicações

2014

Use of laser speckle and entropy computation to segment images of diffuse objects with longitudinal motion.

Autores
Vaz, P; Capela, D; Pereira, T; Correia, C; Ferreira, R; Humeau Heurtier, A; Cardoso, J;

Publicação
SECOND INTERNATIONAL CONFERENCE ON APPLICATIONS OF OPTICS AND PHOTONICS

Abstract
A system using laser speckle effect is proposed to segment images reflecting vibration movements of diffuse targets. Longitudinal movements are difficult to identify when simple imaging systems are used. The proposed system produces a two dimensional segmentation of the target and it is sensitive to longitudinal movements. The speckle effect, produced when coherent light is reflected and interferes when hitting rough surfaces, can be used in order to accomplish this purpose. A pattern with high and low intensity spots is observed depending on the illuminated scene. In our optical system, two silicone membranes are illuminated using a beam expanded laser source and their patterns are recorded using a video camera. One of the membranes experiences a longitudinal controlled movement while the remaining scene is still. Speckle data is processed using a temporal gradient and a regional entropy computation. This method produces a binary individual pixel classification. Four sets of parameters have been tested for the entropy computation and the area under the receiver operating characteristic (ROC) curve was used to select the best one. The selected set-up achieved a ROC value of 0.9879. A data set with 12 different membrane velocities was used to define the threshold that maximizes the classifier accuracy. This threshold was applied to a validation data-set composed by 4 sinusoidal movements with distinct velocities. The accuracy of this technique has achieved values between 92% and 97%. The results show that the target was accurately identified with the optical non-contact apparatus and the developed algorithm.

2014

A Virtual Environment based Serious Game to Support Health Education

Autores
Gomes, T; Abade, T; Campos, JC; Harrison, MD; Silva, JL;

Publicação
EAI Endorsed Trans. Ambient Syst.

Abstract
APEX was developed as a framework for ubiquitous computing (ubicomp) prototyping through virtual environments. In this paper the framework is used as a platform for developing a serious game designed to instruct and to inform. The paper describes the Asthma game, a game aimed at raising awareness among children of asthma triggers in the home. It is designed to stimulate a healthier life-style for those with asthma and respiratory problems. The game was developed as the gamification of a checklist for the home environment of asthma patients.

2014

Production and characterisation of cork pellets: An alternative for sustainable energy recovery

Autores
Nunes, LJR; Matias, JCO; Catalão, JPS;

Publicação
Renewable Energy and Power Quality Journal

Abstract
The cork industry presents itself as one of the most entrepreneurial in the Portuguese industrial sector, contributing significantly to the increase of exports. However, it is an industry in which the use of raw materials is maximised leaving a large volume of waste. The cork industry has tried to take advantage of these residues, mainly through direct energy recovery, despite the technical and safety difficulties presented by the use of such low density material, which complicates and hinders its transportation for industrial uses outside the area in which it is produced. The densification process opens new doors for such use and also for its storage, because it produces better results when compared with other more common products, such as wood sawdust or even forest and agricultural waste. Thus, cork pellets emerge as a safer and more easily transportable alternative for energy recovery from cork dust and other granulated types of cork waste, which offer the prospects for wider use. The results demonstrate that cork pellets have higher calorific value when compared with other biomass pellets; typically, approximately 19 MJ/kg with 2% volume of ashes, which is equivalent to that obtained from the combustion of pellets produced from combined forest and agricultural waste with a bulk density of 640 kg/m3, which offers real advantages in terms of logistics.

2014

Preface

Autores
Vanschoren, J; Brazdil, P; Soares, C; Kotthoff, L;

Publicação
CEUR Workshop Proceedings

Abstract

2014

Analysis of phase interrogation of SPR fiber optic sensors with characteristics tailored by the application of different metal-dielectric overlays

Autores
Moayyed, H; Leite, IT; Coelho, L; Santos, JL; Guerreiro, A; Viegas, D;

Publicação
23RD INTERNATIONAL CONFERENCE ON OPTICAL FIBRE SENSORS

Abstract
Optical fiber sensors based on the phenomenon of plasmonic resonance can be interrogated applying different methods, the most common one being the spectral approach where the measurand information is derived from the reading of the wavelength resonance dip. In principle, a far better performance can be achieved considering the reading of the phase of the light at a specific wavelength located within the spectral plasmonic resonance. This approach is investigated in this work for fiber optic SPR sensors with overlays which are combinations of metallic and dielectric thin films, permitting not only to tune the wavelength of the SPR resonance but also the sensitivity associated with the phase interrogation of the sensors.

2014

Measures for Combining Accuracy and Time for Meta-learning

Autores
Abdulrahman, SM; Brazdil, P;

Publicação
MetaSel@ECAI

Abstract
The vast majority of studies in meta-learning uses only few performance measures when characterizing different machine learning algorithms. The measure Adjusted Ratios of Ratio (ARR) addresses the problem of how to evaluate the quality of a model based on the accuracy and training time. Unfortunately, this measure suffers from a shortcoming that is described in this paper. A new solution is proposed and it is shown that the proposed function satisfies the criterion of monotonicity, unlike ARR.

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