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Publications

2014

Evaporation of volatile compounds in suspended-core fibers

Authors
Moura, JP; Baierl, H; Auguste, JL; Jamier, R; Roy, P; Santos, JL; Frazao, O;

Publication
OPTICS LETTERS

Abstract
A sensing configuration for fluid evaporation monitoring using a suspended-core fiber tip is proposed. Strong differences between the evaporation processes of acetone and isopropyl alcohol were observed, both in terms of the signal's intensity fluctuations and total duration. In each fluid, the main signal variations were due to changes in reflectivity inside a collapsed region of the suspended-core fiber near the spliced interface with a standard single-mode fiber. After further analysis with a wider array of substances, this configuration could, in the future, be used to detect and study the evaporation of different volatile organic compounds. (C) 2014 Optical Society of America

2014

Risk assessment of interruption times affecting domestic and non-domestic electricity customers

Authors
Ilie I.; Hernando-Gil I.; Djokic S.;

Publication
International Journal of Electrical Power and Energy Systems

Abstract
Legislation defined to protect domestic and non-domestic customers from long durations of interruptions includes additional requirements to system's reliability-related performance that distribution network operators (DNOs) must consider in planning the operation and maintenance process of power supply systems. DNOs are required to restore the supply to interrupted customers that fall into "unprotected" customer class within a given period of time, otherwise penalties are applied. In order to meet these requirements, comprehensive strategies must be defined based on upfront analyses. Accordingly, this paper proposes a deterministic algorithm for estimating DNOs' risk of experiencing interruptions with durations above imposed targets. Besides the Regulator-defined legislation, security of supply requirements are engaged in the development of the proposed methodology. Failure analysis of network components is used to identify interrupted customers that are grouped into power demand classes such that the duration of interruptions can be addressed following the security of supply requirements. Moreover, the penalty times defined by the Energy Regulator are engaged in the analysis and used as thresholds to quantify the penalty risk that DNOs are exposed to. The proposed methodology is applied to a typical UK distribution system, whose average reliability performance is also considered in the analysis. © 2013 Elsevier Ltd. All rights reserved.

2014

Real-time hand tracking for rehabilitation and character animation

Authors
Moreira, AHJ; Queiros, S; Fonseca, J; Rodrigues, PL; Rodrigues, NF; Vilaca, JL;

Publication
2014 IEEE 3RD INTERNATIONAL CONFERENCE ON SERIOUS GAMES AND APPLICATIONS FOR HEALTH (SEGAH)

Abstract
Hand and finger tracking has a major importance in healthcare, for rehabilitation of hand function required due to a neurological disorder, and in virtual environment applications, like characters animation for on-line games or movies. Current solutions consist mostly of motion tracking gloves with embedded resistive bend sensors that most often suffer from signal drift, sensor saturation, sensor displacement and complex calibration procedures. More advanced solutions provide better tracking stability, but at the expense of a higher cost. The proposed solution aims to provide the required precision, stability and feasibility through the combination of eleven inertial measurements units (IMUs). Each unit captures the spatial orientation of the attached body. To fully capture the hand movement, each finger encompasses two units (at the proximal and distal phalanges), plus one unit at the back of the hand. The proposed glove was validated in two distinct steps: a) evaluation of the sensors' accuracy and stability over time; b) evaluation of the bending trajectories during usual finger flexion tasks based on the intra-class correlation coefficient (ICC). Results revealed that the glove was sensitive mainly to magnetic field distortions and sensors tuning. The inclusion of a hard and soft iron correction algorithm and accelerometer and gyro drift and temperature compensation methods provided increased stability and precision. Finger trajectories evaluation yielded high ICC values with an overall reliability within application's satisfying limits. The developed low cost system provides a straightforward calibration and usability, qualifying the device for hand and finger tracking in healthcare and animation industries.

2014

Automatic electricity markets data extraction for realistic multi-agent simulations

Authors
Pereira, IF; Sousa, TM; Praca, I; Freitas, A; Pinto, T; Vale, Z; Morais, H;

Publication
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

Abstract
Electricity markets worldwide suffered profound transformations. The privatization of previously nationally owned systems; the deregulation of privately owned systems that were regulated; and the strong interconnection of national systems, are some examples of such transformations [1, 2]. In general, competitive environments, as is the case of electricity markets, require good decision-support tools to assist players in their decisions. Relevant research is being undertaken in this field, namely concerning player modeling and simulation, strategic bidding and decision-support. © 2014 Springer International Publishing Switzerland.

2014

MOVIMENTOS DE VERTENTE NO NORTE DE PORTUGAL: IMPORTÂNCIA DO COMPORTAMENTO HIDROLÓGICO DAS FORMAÇÕES SUPERFICIAIS

Authors
Bateira, CVdM; Soares, LMPM; Rodrigues, DMM; Moura, RMM; Teixeira, MAdC; Santos, MSM;

Publication
RBG - Revista Brasileira de Geomorfologia

Abstract
The occurrence of landslides in northern Portugal has motivated the development of several case studies, rehearsing different methodologies that seek to defi ne and characterize the conditioning factors with the greatest infl uence over the geomorphologic instability processes. This paper presents the results obtained for Frades (Arcos de Valdevez) debris fl ow, discussing the importance of morphostructural context, surfi cial formations and their hydrological behavior, analyzed by in situ and laboratory tests, namely, grain size, mineralogy, hydraulic conductivity, penetration resistance and seismic refraction. The developed study shows the existence of preferential paths of internal water circulation, in combination with constraints linked to the characteristics of the surficial formations, revealing also that the subsurface drainage network has an obvious link with the fl ow that takes place at the surface, although it may present changes motivated by underlying structures.

2014

Renewable Power Forecast to Scheduling of Thermal Units

Authors
Fonte, PM; Santos, B; Monteiro, C; Catalao, JPS; Barbosa, FM;

Publication
TECHNOLOGICAL INNOVATION FOR COLLECTIVE AWARENESS SYSTEMS

Abstract
In this work is discussed the importance of the renewable production forecast in an island environment. A probabilistic forecast based on kernel density estimators is proposed. The aggregation of these forecasts, allows the determination of thermal generation amount needed to schedule and operating a power grid of an island with high penetration of renewable generation. A case study based on electric system of S. Miguel Island is presented. The results show that the forecast techniques are an imperative tool help the grid management.

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