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Viana do Castelo, Portugal

The Polytechnic Institute of Viana do Castelo is a state-run polytechnic institute of higher education in Portugal. Its five schools are located in several cities of the Viana do Castelo district in Portugal. It was established in 16 August 1980. Wikipedia.

Silva L.T.,University of Minho | Oliveira M.,University of Minho | Silva J.F.,Polytechnic Institute of Viana do Castelo
Applied Acoustics

The present paper aims to address the problems of the urban environment as an area of interaction between urban forms and urban noise. This interaction is intended to be monitored using urban indicators, by comparing the effects of noise propagation using models of urban forms. The model of noise prediction allowed developing noise studies in facades, resulting in noise levels in a calculation grid located in the building facades. The study will allow the creation of different scenarios and anticipate as early as in the preliminary building design phase, which facades would be exposed to higher noise levels. The effects of noise in facades can then be minimized in advance, by adjusting the layout of the urban typology. © 2013 Elsevier Ltd. All rights reserved. Source

Rego G.,Polytechnic Institute of Viana do Castelo | Rego G.,INESC Porto
The Scientific World Journal

In the last decade refractometric sensors have attracted an increasing interest by the scientific community due to their ability to perform ambient monitoring, to assess food quality and safety, and also to the fact that they enable the development of label free sensors in the biomedical area. These advances result, namely, from the use of long period fibre gratings in the turning points and/or with thin films in the transition region that allows resolutions of 10-6 to changes in the refractive index of the surrounding medium. Resolutions exceeding 10-8 can also be achieved when long period fibre gratings are combined with evanescent field based devices. This paper reviews the recent path towards the development of ultrahigh sensitive optical fibre refractometric sensors. © 2013 G. Rego. Source

Lopes V.P.,Polytechnic Institute of Braganca | Gabbard C.,Texas A&M University | Rodrigues L.P.,Polytechnic Institute of Viana do Castelo
Journal of Adolescent Health

Purpose: The aim of this study was to determine the influence of dyadic friendship relationships on adolescent physical activity (PA) behavior. Unique to this study was examination of the "best friend" dyad. Methods: Participants were 268 adolescents (13-18 years of age) of both sexes (boys n = 140, girls n = 128), constituting 134 best friendship dyads; 84 were reciprocal best friends and 50 were not. PA was evaluated with the short version of the International Physical Activity Questionnaire. The Actor-Partner Interdependence Model was tested using a hierarchical linear model. First, a null model was run to calculate intraclass correlation coefficient for each type of PA. Next, sex, age, and reciprocity in friendship were included in the model as PA predictors. Results: The null models revealed significant intraclass correlation coefficient values for vigorous PA (VPA) (.32) moderate PA (MPA) (.31), and sitting behavior (.21), but not for walking. Age was the only predictor for VPA, whereas for MPA the predictors were sex and age of the partner. Reciprocity in friendship (best friend) was not a significant predictor for PA. Conclusions: These results indicate a high degree of similarity between best friend dyad in PA, except for walking. The age and sex of the best friend (partner) were important predictors of MPA. The reciprocity in friendship (being reciprocal best friends) was not a relevant variable. © 2013 Society for Adolescent Health and Medicine. All rights reserved. Source

Barreto L.,Polytechnic Institute of Viana do Castelo
Journal of Computer Networks and Communications

Congestion control in wireless networks is strongly dependent on the dynamics and instability of wireless links. Therefore, it is very difficult to accurately evaluate the characteristics of the wireless links. It is known that TCP experiences serious performance degradation problems in wireless networks. Moreover, congestion control mechanisms that rely on network interaction and network parameters, such as XCP and RCP, do not evaluate accurately the capacity and available link bandwidth in wireless networks. In this paper we propose new explicit flow control protocols for wireless mesh networks, based on XCP and RCP. We name these protocols XCP-Winf and RCP-Winf. They rely on the MAC layer information gathered by a new method to accurately estimate the available bandwidth and the path capacity over a wireless network path. The estimation is performed in real time and without the need to intrusively inject packets in the network. These new congestion control mechanisms are evaluated in different scenarios in wireless mesh and ad hoc networks and compared against several new approaches for wireless congestion control. It is shown that both XCP-Winf and RCP-Winf outperform the evaluated approaches, showing its stable behavior and better channel utilization. © 2015 Luís Barreto. Source

Abreu C.,Polytechnic Institute of Viana do Castelo | Ricardo M.,INESC Porto | Mendes P.M.,University of Minho
Journal of Network and Computer Applications

Available wireless sensor networks targeting the domain of healthcare enables the development of new applications and services in the context of E-Health. Such networks play an important role in several scenarios of patient monitoring, particularly those where data collection is vital for diagnosis and/or research purposes. However, despite emerging solutions, wearable sensors still depend on users' acceptance. One proposed solution to improve wearability relies on the use of smaller sensing nodes, requiring more energy-efficient networks, due to smaller room available for energy sources. In such context, smaller wireless sensor network nodes are required to work long time periods without human intervention and, at the same time, to provide appropriate levels of reliability and quality of service. Satisfaction of these two goals depends on several key factors, such as the routing protocol, the network topology, and energy efficiency. This paper offers a solution to increase the network lifetime based on a new Energy-Aware Objective Function used to design a Routing Protocol for Low-Power and Lossy Networks. The proposed Objective Function uses the Expected Transmission Count Metric and the Remaining Energy on each sensor node to compute the best paths to route data packets across the network. When compared with state of the art solutions, the proposed method increases the network lifetime by 21% and reduces the peaks of energy consumption by 12%. In this way, wireless sensor network nodes wearability can be improved, making them smaller and lighter, while maintaining the required performance. © 2013 Elsevier Ltd. Source

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