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Institution

Instituto Superior Técnico

Education
About: Instituto Superior Técnico is a based out in . It is known for research contribution in the topics: Catalysis & Finite element method. The organization has 10085 authors who have published 30226 publications receiving 667524 citations. The organization is also known as: IST & Instituto Superior Tecnico.


Papers
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Journal ArticleDOI
TL;DR: Two different neural network strategies were employed to forecast significant wave heights and zero-up-crossing wave periods 3, 6, 12 and 24h in advance, demonstrating the suitability of the artificial neural technique.

127 citations

Journal ArticleDOI
TL;DR: In this paper, the scalar-tensor scalar field is coupled to the Gauss-Bonnet (GB) term to obtain scalarized static and spherically symmetric black hole (BH) solutions.
Abstract: In this paper, we study static and spherically symmetric black hole (BH) solutions in the scalar-tensor theories with the coupling of the scalar field to the Gauss-Bonnet (GB) term, $\ensuremath{\xi}(\ensuremath{\phi}){R}_{\mathrm{GB}}$, where ${R}_{\mathrm{GB}}\ensuremath{\mathrel{:=}}{R}^{2}\ensuremath{-}4{R}^{\ensuremath{\alpha}\ensuremath{\beta}}{R}_{\ensuremath{\alpha}\ensuremath{\beta}}+{R}^{\ensuremath{\alpha}\ensuremath{\beta}\ensuremath{\mu}\ensuremath{ u}}{R}_{\ensuremath{\alpha}\ensuremath{\beta}\ensuremath{\mu}\ensuremath{ u}}$ is the GB invariant and $\ensuremath{\xi}(\ensuremath{\phi})$ is a function of the scalar field $\ensuremath{\phi}$. Recently, it was shown that in these theories scalarized static and spherically symmetric BH solutions, which are different from the Schwarzschild solution and possess the nontrivial profiles of the scalar field, can be realized for certain choices of the coupling functions and parameters. These scalarized BH solutions are classified in terms of the number of nodes of the scalar field. It was then pointed out that in the case of the pure quadratic order coupling to the GB term, $\ensuremath{\xi}(\ensuremath{\phi})=\ensuremath{\eta}{\ensuremath{\phi}}^{2}/8$, scalarized BH solutions with any number of nodes are unstable against the radial perturbation. In order to see how a higher order power of $\ensuremath{\phi}$ in the coupling function $\ensuremath{\xi}(\ensuremath{\phi})$ affects the properties of the scalarized BHs and their stability, we investigate scalarized BH solutions in the presence of the quartic order term in the GB coupling function, $\ensuremath{\xi}(\ensuremath{\phi})=\ensuremath{\eta}{\ensuremath{\phi}}^{2}(1+\ensuremath{\alpha}{\ensuremath{\phi}}^{2})/8$. We clarify that the existence of the higher order term in the coupling function can realize scalarized BHs with zero nodes of the scalar field which are stable against the radial perturbation.

127 citations

Journal ArticleDOI
TL;DR: It is observed that the alignment of principal strains with the material orthotropy direction is, in general, not possible for all load cases, so less restrictive microstructures (nonorthotropic) will yield higher structural stiffnesses than strictly orthotropic microstructure.
Abstract: Julius Wolff originally proposed that trabecular bone was influenced by mechanical stresses during the formative processes of growth and repair such that trabeculae were required to intersect at right angles. In this work, we have developed an analytical parametric microstructural model, which captures this restriction. Using homogenisation theory, a global material model was obtained. An optimal structure constructed of the homogenised material could then be found by optimising a cost function accounting for both the structural stiffness and the biological cost associated with metabolic maintenance of the bone tissue. The formulation was applied to an example problem of the proximal femur. Optimal densities and orientations were obtained for single load cases. The situation of multiple loads was also considered. In this case, we observe that the alignment of principal strains with the material orthotropy direction is, in general, not possible for all load cases. Thus less restrictive microstruct...

127 citations

Journal ArticleDOI
TL;DR: Petri Net Plans (PNPs) as mentioned in this paper is a language based on Petri Nets (PNs) that allows for intuitive and effective robot and multi-robot behavior design.
Abstract: Programming the behavior of multi-robot systems is a challenging task which has a key role in developing effective systems in many application domains. In this paper, we present Petri Net Plans (PNPs), a language based on Petri Nets (PNs), which allows for intuitive and effective robot and multi-robot behavior design. PNPs are very expressive and support a rich set of features that are critical to develop robotic applications, including sensing, interrupts and concurrency. As a central feature, PNPs allow for a formal analysis of plans based on standard PN tools. Moreover, PNPs are suitable for modeling multi-robot systems and the developed behaviors can be executed in a distributed setting, while preserving the properties of the modeled system. PNPs have been deployed in several robotic platforms in different application domains. In this paper, we report three case studies, which address complex single robot plans, coordination and collaboration.

127 citations


Authors

Showing all 10288 results

NameH-indexPapersCitations
Joao Seixas1531538115070
A. Gomes1501862113951
Amartya Sen149689141907
António Amorim136147796519
Joao Varela133141192438
Pietro Faccioli132137889795
João Carvalho126127877017
Pedro Jorge12477668658
Pedro Silva12496174015
A. De Angelis11853454469
Hermine Katharina Wöhri11662955540
Helena Santos114105854286
P. Conde Muiño10955856133
Joao Saraiva10751953340
J. N. Reddy10692666940
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202341
2022354
20212,263
20202,433
20192,327
20182,190