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Publications

2013

Using the Action-Research Method in Information Systems Planning Creativity research

Authors
Santos, V; Amaral, L; Mamede, H;

Publication
PROCEEDINGS OF THE 2013 8TH IBERIAN CONFERENCE ON INFORMATION SYSTEMS AND TECHNOLOGIES (CISTI 2013)

Abstract
Considering the global competitiveness the organizations ability to effectively use information technologies and bet on innovation and creativity are today commonly recognized as important. In this context, research on creativity in information systems has assumed special importance. This paper illustrates the use of Action-Research Method "in research in Information Systems and Creativity, particularized in Information Systems Planning, reflecting on the advantages of using this method in this context.

2013

The Carousel-EDF Scheduling Algorithm for Multiprocessor Systems

Authors
Sousa, PB; Souto, P; Tovar, E; Bletsas, K;

Publication
2013 IEEE 19TH INTERNATIONAL CONFERENCE ON EMBEDDED AND REAL-TIME COMPUTING SYSTEMS AND APPLICATIONS (RTCSA)

Abstract
We present Carousel-EDF, a new hierarchical scheduling algorithm for a system of identical processors, and its overhead-aware schedulability analysis based on demand bound functions. Carousel-EDF is an offshoot of NPS-F and preserves its utilization bounds, which are the highest among algorithms not based on a single dispatching queue and that have few preemptions. Furthermore, with respect to NPS-F, Carousel-EDF reduces by up to 50% the number of context switches and of preemptions caused by the high-level scheduler itself. The schedulability analysis we present in this paper is grounded on a prototype implementation of Carousel-EDF that uses a new implementation technique for the release of periodic tasks. This technique reduces the pessimism of the schedulability analysis presented and can be applied, with similar benefits, to other scheduling algorithms such as NPS-F.

2013

Integrating formal predictions of interactive system behaviour with user evaluation

Authors
Ruksenas, R; Curzon, P; Harrison, MD;

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

Abstract
It is well known that human error in the use of interactive devices can have severe safety or business consequences. It is important therefore that aspects of the design that compromise the usability of a device can be predicted before deployment. A range of techniques have been developed for identifying potential usability problems including laboratory based experiments with prototypes and paper based evaluation techniques. This paper proposes a framework that integrates experimental techniques with formal models of the device, along with assumptions about how the device will be used. Abstract models of prototype designs and use assumptions are analysed using model checking techniques. As a result of the analysis hypotheses are formulated about how a design will fail in terms of its usability. These hypotheses are then used in an experimental environment with potential users to test the predictions. Formal methods are therefore integrated with laboratory based user evaluation to give increased confidence in the results of the usability evaluation process. The approach is illustrated by exploring the design of an IV infusion pump designed for use in a hospital context. © 2013 Springer-Verlag Berlin Heidelberg.

2013

Adaptation and validation of flexible and rigid control subscales of eating behavior [Adaptação e validação das sub-escalas de controlo flexível e rígido do comportamento alimentar]

Authors
Poinhos, R; Rowcliffe, P; Marques, AR; Viana, V; Oliveira, BMPM; Correia, F;

Publication
Revista de Alimentacao Humana

Abstract
Our aim was to adapt for Portuguese and validate the flexible and rigid control subscales of eating behaviour proposed by Westenhoefer et al. (1999) and to analyse their relationship with socio-demographic and anthropometric variables. One sample from the general population (n = 231) and another composed by higher education students (n = 257) were evaluated. The adaptation of the subscales involved their translation, back translation and cultural adaptation. The subscales' final version showed unifactorial structure and acceptable internal consistency in both samples (Cronbach's alpha between 0,750 and 0,817). Higher scores in each subscale correspond to higher dietary restraint. Women had higher levels of both types of control. For men age was positively associated with flexible control, and for women education was positively associated with both types of restraint. In the students' sample, rigid control significantly predicted BMI (positive association). The present study supplies an instrument to assess flexible and rigid control of eating behaviour adapted to the Portuguese population.

2013

Development of an electrical current sensor prototype for applications in high-power lines

Authors
Nascimento, IM; Brigida, ACS; Baptista, M; Costa, JCWA; Martinez, MAG; Jorge, PAS;

Publication
8TH IBEROAMERICAN OPTICS MEETING AND 11TH LATIN AMERICAN MEETING ON OPTICS, LASERS, AND APPLICATIONS

Abstract
A magneto-optical current sensor, based on a low birefringence SF57 glass prism, using a dual quadrature polarimetric configuration was implemented and tested aiming its application in high voltage power lines. Sensor operation is characterized and compared using distinct Super Luminescent Diodes as optical sources, with emission at 650 nm, 830 nm and 1550 nm. Calibration and resolution are obtained in the different operating conditions using a DAQ board and full digital control for signal acquisition and processing. In particular, the sensor was tested in the range from 0 to 1 kA at 50 Hz. Also, operation at different frequencies from 50 Hz to 400 Hz was compared. A robust casing was fabricated in Nylon material enabling the portability of the sensor and its application in different types of conductors. Preliminary results indicate the feasibility of using the sensor both for metering and protection applications in high-power lines with interrogation via the OPGW cable.

2013

Interrogation Sensing Scheme Based on a Figure-of-Eight Fiber Loop Mirror

Authors
Silva, RM; Layeghi, A; Zibaii, MI; Latifi, H; Santos, JL; Ribeiro, ABL; Frazao, O;

Publication
IEEE PHOTONICS TECHNOLOGY LETTERS

Abstract
A fiber optic interrogation sensor scheme based on a "figure-of-eight" configuration created from a single directional 3 x 3 fiber optic coupler is proposed. Two loops are formed in each arm and one of them contains the sensing head and the other is used as reference signal. A theoretical study based on Jones matrix analysis of this fiber loop mirror combination is reported. The optical configuration is tested as an interrogation scheme for a fiber strain sensor where the spectral response arises from the combination of the reference signal modulated by the sensor signal. The strain sensor configuration shows a phase sensitivity of 6.7 +/- 4.38 x 10(-2) mrad/mu strain by linear regression.

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