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Publicações

Publicações por HumanISE

2008

Dynamic joint stiffness of the ankle during walking: Gender-related differences

Autores
Gabriel, RC; Abrantes, J; Granata, K; Bulas Cruz, J; Melo Pinto, P; Filipe, V;

Publicação
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

A comparison of two-dimensional and three-dimensional techniques for the determination of hindlimb kinematics during treadmill locomotion in rats following spinal cord injury

Autores
Couto, PA; Filipe, VM; Magalhaes, LG; Pereira, JE; Costa, LM; Melo Pinto, P; Bulas Cruz, J; Mauricio, AC; Geuna, S; Varejao, ASP;

Publicação
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

Fast and straightforward method to estimate sub-pixel level displacement field

Autores
Sousa, A; Morais, J; Filipe, V; Jesus, A; Vaz, MAP;

Publicação
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

Fuzziness measure approach to automatic histogram threshold

Autores
Lopes, NV; Bustince, H; Filipe, V; Pinto, PM;

Publicação
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

Automatic reading of attendance in the classroom: Integration with the information system for teaching support [Leitura automática de presenças em sala de aula: Integração com o sistema de informação de apoio ao ensino]

Autores
Barbosa, L; Filipe, V; Bulas Cruz, J; Barroso, J;

Publicação
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

2008

Tools for the Information System Function Management: A Roadmap

Autores
Trigo, A; Varajao, J; Barroso, J;

Publicação
OPEN KNOWLEDGE SOCIETY: A COMPUTER SCIENCE AND INFORMATION SYSTEMS MANIFESTO

Abstract
Information technology and information systems have evolved dramatically over the last half-century, playing an absolutely central and crucial role in the success of today's organizations. Therefore, the complexity of the information systems function has also increased significantly, which requires the use of more evolved software tools to support the information system function activities. In this paper we present a matrix of the main tools available for the information system function, which can help Chief Information Officers to identify the right tools to use in their departments.

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