2008
Authors
Salvador, N; Filipe, V; Rabadão, C; Pereira, A;
Publication
3rd International Conference on Systems and Networks Communications, ICSNC 2008, Sliema, Malta, October 26-31, 2008
Abstract
Currently, due to questions of financial order, the Internet Service Providers do not invest in rural areas, because the investment does not pay. This fact originates, more and more, the appearance of the so called WBN (Wireless Broadband Networks), that are going to supply Internet access to the populations, discriminated by this circumstance. The aspects related to the management of these networks are normally forgotten and today there is a lack of economically and technical viable solutions, that can efficiently help with this function, without use an enterprise solution. After an intensive research of commercial and opensource solutions of wireless networks management, it was checked an absence of an economically viable solution as well as an absence of a model of management for the WBN. This article contributes to the definition of a management model of these networks, using opensource tools. The proposal model is based on a centralized solution that congregates several modules of opensource tools, which can be able to respond to a wide range of features identified in the model. The simulation shows how the model presented, can be practicable and able to cover several functions in WBN management. © 2008 IEEE.
2008
Authors
Gabriel, RC; Abrantes, J; Granata, K; Bulas Cruz, J; Melo Pinto, P; Filipe, V;
Publication
PHYSICAL THERAPY IN SPORT
Abstract
Objectives: To characterize and compare dynamic joint stiffness (DJS) of the ankle in the sagittal plane during natural cadence walking in both genders. Design: Observation, cross-sectional and matched pairs. Participants: Twenty-one males (mean age = 27 +/- 4.2 years) and 18 females (mean age = 22.9 +/- 4.1 years). Setting: Laboratory at the University de Tras-os-Montes and Alto Douro. The DJS of the ankle was assessed while participants performed barefoot walking at a natural cadence, was measured using a force platform (1000 Hz), and synchronized with a high-speed camera (200 Hz). Main outcome measures: DJS of the ankle in males and females was calculated in two sub-phases (the second and the fourth sub-phases) of the stance phase. The Wilcoxon non-parametric matched-pairs test and the Mann-Whitney U non-parametric test were used to analyse difference of DJS of the ankle within and between the groups with p <= 0.05 regarded as significant. Results: Male and female participants demonstrated significantly (p<0.005) less DJS during the second sub-phase. DJS was not significantly (p>0.063) different between females (0.0511 N m/kg/degrees) and males (0.0596 N m/kg/degrees) during the second sub-phase. DJS was significantly (p<0.001) higher in males (0.0844 N m/kg/degrees) than females (0.0691 N m/kg/degrees) during the fourth sub-phase. Conclusions: Gender-specific DJS characteristics demonstrated by females in this study may be used in preventative training programs designed to promote a greater ability to use contractile components to produce mechanical energy through the ankle.
2008
Authors
Couto, PA; Filipe, VM; Magalhaes, LG; Pereira, JE; Costa, LM; Melo Pinto, P; Bulas Cruz, J; Mauricio, AC; Geuna, S; Varejao, ASP;
Publication
JOURNAL OF NEUROSCIENCE METHODS
Abstract
Of all the detrimental effects of spinal cord injury (SCI), one of the most devastating effects is the disruption of the ability to walk. Therefore, much effort has been focused on developing several methods to document the recovery of locomotor function after experimental SCI. Computerized rat gait analysis is becoming increasingly popular in the SCI research community. The two-dimensional (2D) kinematic approach is by far the most popular technique in rat gait analysis. This is a simple inexpensive procedure, which requires only one camera to record the movement. Our study included an examination of locomotion on a treadmill using 2D and three-dimensional (3D) analysis, in neurologically intact animals and following moderate T9 contusion injury. Despite the overall time course patterns of the curves were identical, we found significant differences between values of the 2D and 3D joint angular motion. In conclusion, maximal precision and accuracy of the kinematic values are expected when the experimental protocol includes a 3D motion analysis methodology. Moreover, a 2D method cannot be used to determine the external or internal rotations of the foot because this movement occurs in the transverse plane.
2008
Authors
Sousa, A; Morais, J; Filipe, V; Jesus, A; Vaz, MAP;
Publication
COMPUTATIONAL VISION AND MEDICAL IMAGING PROCESSING
Abstract
This paper presents a fast and straightforward method to assess displacement fields on the surface of a planar specimen with sub-pixel resolution. First, pixel level displacements are obtained by cross correlation (CC) of two consecutive images, used as the image similarity measure. Next, sub-pixel displacement information is calculated from the CC coefficients matrix using a similarity interpolation method. Finally, sub-pixel estimation error cancellation is performed. Several experiments were conducted to validate the proposed method effectiveness, applied to chestnuts compression test for quality control purposes.
2008
Authors
Lopes, NV; Bustince, H; Filipe, V; Pinto, PM;
Publication
COMPUTATIONAL VISION AND MEDICAL IMAGING PROCESSING
Abstract
In this paper, an automatic histogram threshold approach based on a fuzziness measure is presented. This work is an improvement of an existing method. Using fuzzy logic concepts, the problems to find a minima of a criterion function are avoided. Similarity between gray levels is the key to find an optimal threshold. Two initial regions of gray levels, located at the boundaries of the histogram, are defined. Then, using an index of fuzziness, a similarity process is started to find the threshold point. A significant contrast between objects and background is assumed. Previous histogram equalization is used in small contrast images. No pior knowledge of the image is required.
2008
Authors
Barbosa, L; Filipe, V; Bulas Cruz, J; Barroso, J;
Publication
CISCI 2008 - Septima Conferencia Iberoamericana en Sistema, Cibernetica e Informatica 5to SIECI 2008, 3er Simposium Internacional en Comunicacion del Conocimiento y Conferencias, CCC 2008 - Memorias
Abstract
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