Browsing by Author "Martins, J."
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- An energy-aware resource design model for constrained networksPublication . Correia, N.; Schütz, Gabriela; Mazayev, A.; Martins, J.; Barradas, A.The Internet of Things is expected to incorporate objects and sensor networks of all kinds, and in particular, constrained sensor networks where energy consumption is a critical issue. In order to increase the lifetime of such networks, intelligent and standard-based solutions should be used. Here, we address this challenge through the use of CoRE interfaces for the resource design. These interfaces allow the server side to compose/organize resources and the client side to discover and determine how to consume such resources, besides allowing decisions to be easily integrated into the operation of the network. An energy-aware resource design model is proposed, based on CoRE interfaces, for the design of resources matching client needs. Based on this model, we develop an algorithm that proved to be energy efficient.
- Ecological quality assessment of transitional waters based on fish assemblages in Portuguese estuaries: The Estuarine Fish Assessment Index (EFAI)Publication . Cabral, H. N.; Fonseca, V. F.; Gamito, R.; Gonçalves, C. I.; Costa, J. L.; Erzini, Karim; Gonçalves, Jorge Manuel Santos; Martins, J.; Leite, L.; Andrade, José Pedro; Ramos, S.; Bordalo, A.; Amorim, E.; Neto, J. M.; Marques, J. C.; Rebelo, J. E.; Silva, C.; Castro, N.; Almeida, P. R.; Domingos, I.; Gordo, L. S.; Costa, M. JThe assessment of water quality has changed markedly worldwide over the last years, especially in Europe due to the implementation of the Water Framework Directive. Fish was considered a key-element in this context and several fish-based multi-metric indices have been proposed. In this study, we propose a multi-metric index, the Estuarine Fish Assessment Index (EFAI), developed for Portuguese estuaries, designed for the overall assessment of transitional waters, which could also be applied at the water body level within an estuary. The EFAI integrates seven metrics: species richness, percentage of marine migrants, number of species and abundance of estuarine resident species, number of species and abundance of piscivorous species, status of diadromous species, status of introduced species and status of disturbance sensitive species. Fish sampling surveys were conducted in 2006, 2009 and 2010, using beam trawl, in 13 estuarine systems along the Portuguese coast. Most of the metrics presented a high variability among the transitional systems surveyed. According to the EFAI values, Portuguese estuaries presented a "Good" water quality status (except the Douro in a particular year). The assessments in different years were generally concordant, with a few exceptions. The relationship between the EFAI and the Anthropogenic Pressure Index (API) was not significant, but a negative and significant correlation was registered between the EFAI and the expert judgement pressure index, at both estuary and water body level. The ordination analysis performed to evaluate similarities among North-East Atlantic Geographical Intercalibration Group (NEAGIG) fish-based indices put in evidence four main groups: the French index, since it is substantially different from all the other indices (uses only four metrics based on densities); indices from Ireland, United Kingdom and Spain (Asturias and Cantabria); the Dutch and German indices; and the indices of Belgium. Portugal and Spain (Basque country). The need for detailed studies, including comparative approaches, on several aspects of these assessment tools, especially in what regards their response to anthropogenic pressures was stressed. (C) 2011 Elsevier Ltd. All rights reserved.
- Ecological quality assessment of transitional waters based on fish assemblages in Portuguese estuaries: the Estuarine Fish Assessment Index (EFAI)Publication . Cabral, H. N.; Fonseca, V. F.; Gamito, R.; Gonçalves, C. I.; Costa, J. L.; Erzini, Karim; Gonçalves, J. M. S.; Martins, J.; Leite, L.; Andrade, José Pedro; Ramos, S.; Bordalo, A.; Amorim, E.; Neto, J. M.; Marques, J. C.; Rebelo, J. E.; Silva, C.; Castro, N.; Almeida, P. R.; Domingos, I.; Gordo, L. S.; Costa, M. J.The assessment of water quality has changed markedly worldwide over the last years, especially in Europe due to the implementation of the Water Framework Directive. Fish was considered a key-element in this context and several fish-based multi-metric indices have been proposed. In this study, we propose a multimetric index, the Estuarine Fish Assessment Index (EFAI), developed for Portuguese estuaries, designed for the overall assessment of transitional waters, which could also be applied at the water body level within an estuary. The EFAI integrates seven metrics: species richness, percentage of marine migrants, number of species and abundance of estuarine resident species, number of species and abundance of piscivorous species, status of diadromous species, status of introduced species and status of disturbance sensitive species. Fish sampling surveys were conducted in 2006, 2009 and 2010, using beam trawl, in 13 estuarine systems along the Portuguese coast. Most of the metrics presented a high variability among the transitional systems surveyed. According to the EFAI values, Portuguese estuaries presented a “Good” water quality status (except the Douro in a particular year). The assessments in different years were generally concordant, with a few exceptions. The relationship between the EFAI and the Anthropogenic Pressure Index (API) was not significant, but a negative and significant correlation was registered between the EFAI and the expert judgement pressure index, at both estuary and water body level. The ordination analysis performed to evaluate similarities among North-East Atlantic Geographical Intercalibration Group (NEAGIG) fish-based indices put in evidence four main groups: the French index, since it is substantially different from all the other indices (uses only four metrics based on densities); indices from Ireland, United Kingdom and Spain (Astúrias and Cantábria); the Dutch and German indices; and the indices of Belgium, Portugal and Spain (Basque country). The need for detailed studies, including comparative approaches, on several aspects of these assessment tools, especially in what regards their response to anthropogenic pressures was stressed.
- Fátima revisited: an interactive installationPublication . Alves, Ricardo; Madeira, Marisa; Ferrer, Jorge; Costa, Susana; Lopes, D.; Silva, Bruno; Sousa, L.; Martins, J.; Rodrigues, J. M. F.Three very young shepherds, on May 13, 1917, reported seeing “... a lady even brighter than the sun...”, floating a meter or so in the air, near an old oak tree, when they were pasturing their little herd in Cova da Iria, Portugal. The story of OurLady of Fátima has remained one of the most remarkable odes in Portuguese folklore. It is, beyond the religious event in itself, a key episode in the official history and culture of the Portu-guese people. It is a day celebrated every year; more among thefaithful believers, but also in the media and even as a political catchphrase, widespread, recognized and cele-brated, including by the Vatican and several Popes. In this paper, we present two mul-timedia installations where the central figure is Our Ladyof Fátima, following two main ideas: (a) a “door” opens up the possibility to access multiple space-time experiments, and (b) we try to reach into the Portuguese imaginary surrounding the appearance of Our Lady of Fátima, using a female archetype suggesting a “sacred apparition”. Both installations use a Microsoft Kinect sensor to detect the presence of a viewer for trigger-ing the start of the narrative, followed by recognizing different movements of the view-er(s), e.g., moving left, right, forward, backward, etc., to create different flows in the presented narrative –even at some point changing the face of Our Lady of Fátima with the face of the viewer. Both installations use similar hardware and software concepts, except that the first one uses a Rear Projection solution where the narrative is presented by the image of Our Lady in real size and the second uses a Hologram.
- Measuring dielectric constants of lipid bilayers: monitoring scatter effects in pyrene fluorescencePublication . Cristo, Joana; Silva, A.; Martins, J.Pyrene (Py) fluorescence is expedient to study biophysical phenomena in lipid bilayer due to high quantum yield, long lifetime and precise solvatochromic effects [1]. The physicalchemical properties of Py settle its location in the ordered section of the methylenic palisade stating the values of dielectric constants of bilayers, averaged transversally in space (the longest axis of Py, 9.2 ˚A) and laterally in time (due to lateral diffusion of Py during its lifetime, 150 ns) [2].
- Robustness of the Estuarine Fish Assessment Index (EFAI) regarding water body definition criteriaPublication . Gonçalves, C. I.; Pasquaud, S.; Gamito, R.; Fonseca, V. F.; Costa, J. L.; Erzini, Karim; Gonçalves, Jorge Manuel Santos; Martins, J.; Leite, L.; Castro, N.; Andrade, José Pedro; Ramos, S.; Bordalo, A.; Amorim, E.; Neto, J. M.; Marques, J. C.; Costa, M. J.; Cabral, H.According to the Water Framework Directive (WFD) transitional waters should be differentiated according to type and, in some cases, divided into different water bodies. This raises a dilemma in trying to define parts of a continuum. In the sequence of WFD several indices have been proposed including the Estuarine Fish Assessment Index, which can be applied taking an estuary as a whole (EFAI - without water bodies division) or divided in water bodies (EFAI(WB)). The purpose of this work is to analyze the robustness of the Estuarine Fish Assessment Index, based on three different ways of dividing Portuguese estuaries into water bodies according to different criteria (criterion 1 - distance to the estuary mouth, criterion 2 - salinity and criterion 3 - morphology, salinity and human dimension as pressure and state). In this study we evaluated at which degree these three criteria could influence the ecological quality ratio (EQR) results, when the index was applied to water body level (EFAI(WB)). Also, for each estuary, the EQR(WB) results for each criterion of EFAI(WB) were combined and weighted according to the water bodies areas (EFAI overall weighted - EFAI(Ow)). Finally, it was compared if the results obtained for each criterion with the EFAI(OW) were similar to the results of the index application taking the estuary as a whole (EFAI without water bodies division). No significant differences were found in both cases, which indicated that this index is a robust method regarding the division of the estuaries in different water bodies, which is an important element of a fish-based multimetric tool for assessing estuarine ecological quality. However, in some cases, different ecological quality statuses were achieved when applying the EFAI(Ow) or the EFAI. This work addressed several aspects regarding the possible division of water bodies at the WFD context. (C) 2012 Elsevier Ltd. All rights reserved.
- Spatially-resolved photocapacitance measurements to study defects in a-Si:H based p-i-n particle detectorsPublication . Casteleiro, C.; Schwarz, R.; Mardolcar, U.; Maçarico, A.; Martins, J.; Vieira, M.; Wuensch, F.; Kunst, M.; Morgado, E.; Stallinga, Peter; Gomes, Henrique L.Thick large-area particle or X-ray detectors suffer degradation during operation due to creation of defects that act as deep traps. Measuring the photocurrent under homogeneously absorbed weak light can monitor variation in detector performance. We describe how photocapacitance can be used as an alternative method to measure the creation of defects and their energy level after intense irradiation with protons or He ions at 1.5 MeV and after exposure to intense laser pulses. The possibility to detect small areas of high defect density in a large-area detector structure is discussed.