2018
Autores
Vilanova, SP; Narciso, J; Carvalho, JP; Lopes, I; Quinta Ferreira, M; Pinto, CC; Moura, R; Borges, J; Nemser, ES;
Publicação
BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA
Abstract
The inclusion of site-specific conditions is essential to adequately represent the seismic hazard and the seismic risk for a region. We acquired, gathered, and organized a near-surface shear-wave velocity database for Portugal and applied a three-step methodological approach for developing a V-S30 site-condition map using extrapolation based on surface geology. The methodology includes (1) defining a preliminary set of geologically defined units, (2) calculating the probability distribution of log V-S30 for each unit, and (3) merging the units according to the results of statistical tests. The final model comprises three geologically defined units characterized by log V-S30 distributions that are statistically significantly different from each other: F1, igneous, metamorphic, and old sedimentary rocks; F2, Neogene and Pleistocene formations; and F3, Holocene formations. The site conditions for the F3 unit may be further refined using correlations with topographic slope based on the Shuttle Radar Topography Mission at 3 arcsec resolution (SRTM3) dataset. We analyzed the performance site-condition models based on correlations with exogenous data (topographic slope and surface-geology analogs). The results show that the residual distributions between log V-S30 values measured and estimated from those proxies are strongly biased for some geological units, emphasizing the need for acquiring regional V-S data.
2018
Autores
Faria, CL; Goncalves, LM; Martins, MS; Lima, R;
Publicação
2018 OCEANS - MTS/IEEE KOBE TECHNO-OCEANS (OTO)
Abstract
device to increase energy autonomy of moored oceanographic monitoring stations. Oscillations and currents through the sea or river are used to produce energy when the whole system is submerged to a depth between 3 to 10 meters. In order to have an inexpensive system, a buoy containing a Linear Electromagnetic Generator (LEG), is fabricated in a 3D printer, using PLA (polylactic acid) filament. Inside of the buoy, one cylinder shaped LEG (98mm length and 25mm of diameter) produces a maximum output power of 20 mW with a 4 Hz movement. To increase power output in larger systems, more LEGs can be added.
2018
Autores
Azevedo Perdicoúlis, TPC;
Publicação
International Journal of Control
Abstract
2018
Autores
Azevedo Perdicoulis, TPCA;
Publicação
INTERNATIONAL JOURNAL OF CONTROL
Abstract
2017
Autores
Matos, A; Silva, E; Almeida, J; Martins, A; Ferreira, H; Ferreira, B; Alves, J; Dias, A; Fioravanti, S; Bertin, D; Lobo, V;
Publicação
Search and Rescue Robotics - From Theory to Practice
Abstract
2017
Autores
Cruz, N; Abreu, N; Almeida, J; Almeida, R; Alves, J; Dias, A; Ferreira, B; Ferreira, H; Gonçalves, C; Martins, A; Melo, J; Pinto, A; Pinto, V; Silva, A; Silva, H; Matos, A; Silva, E;
Publicação
OCEANS 2017 - ANCHORAGE
Abstract
This paper describes the PISCES system, an integrated approach for fully autonomous mapping of large areas of the ocean in deep waters. A deep water AUV will use an acoustic navigation system to compute is position with bounded error. The range limitation will be overcome by a moving baseline scheme, with the acoustic sources installed in robotic surface vessels with previously combined trajectories. In order to save power, all systems will have synchronized clocks and implement the One Way Travel Time scheme. The mapping system will be a combination of an off-the-shelf MBES with a new long range bathymetry system, with a source on a moving surface vessel and the receivers on board the AUV. The system is being prepared to participate in round one of the XPRIZE challenge.
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