Encontrados 12 documentos, a visualizar página 1 de 2
Projetos de realidade virtual
Cardoso, VitorInforAbERTA 2014 - IV Jornadas de Informática ; Apresentação efetuada nas IV Jornadas de Informática da Universidade Aberta.
Prototype of a side-row Continuous Canopy Shaking Harvester for Intensive Olive...
Peça, José; Dias, António; Cardoso, Vitor; Souza, Domingos; Falcão, José; Pinheiro, AnacletoOlive producing countries worldwide invested largely in high density groves varying from 200 to 550 trees per hectare for which no efficient totally mechanized harvesting methodology and technology is available. Trunk shaking is not an adequate option due to lack of space and intense strain in labour and machinery. Continuous canopy shaking is the obvious approach, not only increasing working capacity but also ...
Higher-dimensional puncture initial data
Zilhão, Miguel; Ansorg, Marcus; Cardoso, Vitor; Gualtieri, Leonardo; Herdeiro, Carlos; Sperhake, Ulrich; Witek, HelviWe calculate puncture initial data, corresponding to single and binary black holes with linear momenta, which solve the constraint equations of D-dimensional vacuum gravity. The data are generated by a modification of the pseudospectral code presented in [M. Ansorg, B. Bruegmann, and W. Tichy, Phys. Rev. D 70, 064011 (2004).] and made available as the TWOPUNCTURES thorn inside the CACTUS computational toolkit. ...
Head-on collisions of unequal mass black holes in D=5 dimensions
Witek, Helvi; Cardoso, Vitor; Gualtieri, Leonardo; Herdeiro, Carlos; Sperhake, Ulrich; Zilhao, MiguelWe study head-on collisions of unequal mass black hole binaries in D = 5 spacetime dimensions, with mass ratios between 1:1 and 1:4. Information about gravitational radiation is extracted by using the Kodama-Ishibashi gauge-invariant formalism and details of the apparent horizon of the final black hole. We present waveforms, total integrated energy and momentum for this process. Our results show surprisingly go...
Numerical Relativity in D dimensional space-times: Collisions of unequal mass b...
Witek, Helvi; Cardoso, Vitor; Gualtieri, Leonardo; Herdeiro, Carlos; Sperhake, Ulrich; Zilhão, MiguelWe present unequal mass head-on collisions of black holes in D = 5 dimensional space-times. We have simulated BH systems with mass ratios q = 1,1/2,1/3,1/4. We extract the total energy radiated throughout the collision and compute the linear momentum flux and the recoil velocity of the final black hole. The numerical results show very good agreement with point particle calculations when extrapolated to this limit.
Simulations of black holes in compactified spacetimes
Zilhão, Miguel; Cardoso, Vitor; Gualtieri, Leonardo; Herdeiro, Carlos; Nerozzi, Andrea; Sperhake, Ulrich; Witek, HelviFrom the gauge/gravity duality to braneworld scenarios, black holes in compactified spacetimes play an important role in fundamental physics. Our current understanding of black hole solutions and their dynamics in such spacetimes is rather poor because analytical tools are capable of handling a limited class of idealized scenarios, only. Breakthroughs in numerical relativity in recent years, however, have opene...
Foreign Multinationals and Domestic Companies in Portugal: Are there Significan...
Cardoso, Vítor Manuel dos SantosFirm Performance has been pointed by different authors as an important research matter in International Business, notably in multinational corporations (MNCs). Organisations in general coordinate their activities by objectives and compete to seek competitive advantage via performance. This dissertation investigates if foreign owned (FO) and domestic owned (DO) firms differ in comparative performance. Specifical...
Black holes in a box: Toward the numerical evolution of black holes in AdS spac...
Witek, Helvi; Cardoso, Vitor; Herdeiro, Carlos; Nerozzi, Andrea; Sperhake, Ulrich; Zilhão, MiguelThe evolution of black holes in "confining boxes" is interesting for a number of reasons, particularly because it mimics the global structure of anti-de Sitter geometries. These are nonglobally hyperbolic space-times and the Cauchy problem may only be well defined if the initial data are supplemented by boundary conditions at the timelike conformal boundary. Here, we explore the active role that boundary condit...
Numerical relativity for D dimensional space-times: Head-on collisions of black...
Witek, Helvi; Zilhão, Miguel; Gualtieri, Leonardo; Cardoso, Vitor; Herdeiro, Carlos; Nerozzi, Andrea; Sperhake, UlrichHigher dimensional black holes play an exciting role in fundamental physics, such as high energy physics. In this paper, we use the formalism and numerical code reported in [1] to study the head-on collision of two black holes. For this purpose we provide a detailed treatment of gravitational wave extraction in generic D dimensional space-times, which uses the Kodama-Ishibashi formalism. For the first time, we ...
Aprender a inovar : contextos virtuais e ambientes inteligentes de aprendizagem
Cardoso, VitorTese de Doutoramento em Informática na especialidade de Informática apresentada à Universidade Aberta ; A comunicação, as suas dificuldades, problemas e consequências sempre foram um calcanhar de Aquiles na Educação a distância como é referido por inúmeros autores. Focar o Ensino a Distância (EaD) na disponibilização de informação e na distribuição de conteúdos, como tem sido a atitude mais generalizada, resol...
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