Repositório Colecção:https://hdl.handle.net/1822/122422024-03-28T17:43:49Z2024-03-28T17:43:49ZPara alem do binário: Lógica Fuzzy na modelação de problemas complexosCastro, Cecíliahttps://hdl.handle.net/1822/869842023-10-19T08:34:04Z2023-10-19T08:34:04ZTítulo: Para alem do binário: Lógica Fuzzy na modelação de problemas complexos
Autor: Castro, Cecília
<b>Tipo</b>: oralPresentation2023-10-19T08:34:04ZLanczos potentials for linearly perturbed FLRW spacetimesMena, Filipe C.Tod, Paulhttps://hdl.handle.net/1822/661842020-07-30T09:58:21Z2020-07-30T09:01:49ZTítulo: Lanczos potentials for linearly perturbed FLRW spacetimes
Autor: Mena, Filipe C.; Tod, Paul
Resumo: We study the problem of deriving the Lanczos potential and superpotential for linearly perturbed Friedman-Lemaitre-Robertson-Walker (FLRW) spacetimes.
<b>Tipo</b>: conferencePaper2020-07-30T09:01:49ZPreface of the “Symposium on Numerical Optimization and Applications”Pereira, Ana I.Costa, M. Fernanda P.https://hdl.handle.net/1822/637702020-02-06T15:24:26Z2020-02-06T13:50:56ZTítulo: Preface of the “Symposium on Numerical Optimization and Applications”
Autor: Pereira, Ana I.; Costa, M. Fernanda P.
Resumo: [Excerpt] Numerical Optimization and Applications Symposium emphasizes modeling, theory and study of numerical algorithms for optimization. Optimization is an important tool in decision science and in the analysis of physical systems. Because of the wide and growing use of optimization in science, engineering, economics, finance and industry, it is important to develop an understanding of optimization algorithms. Knowledge of the capabilities and limitations of these algorithms leads to a better understanding of their impact on various applications, and points the way to future research on improving and extending optimization algorithms and software. [...]
<b>Tipo</b>: conferenceEditorial2020-02-06T13:50:56ZUniversal fluctuations of the S&100 stock index returnsGonçalves, RuiPinto, Albertohttps://hdl.handle.net/1822/637322020-02-07T12:50:38Z2020-02-05T10:17:13ZTítulo: Universal fluctuations of the S&100 stock index returns
Autor: Gonçalves, Rui; Pinto, Alberto
Resumo: We analyze the constituents stocks of the well known Standard & Poor’s 100 index (S&P100) that are traded in the NYSE and NASDAQ markets. We observe the data collapse of the histogram of the S&P100 index fluctuations to the universal non‐parametric Bramwell‐Holdsworth‐Pinton (BHP) distribution. Since the BHP probability density function appears in several other dissimilar phenomena, our result reveals an universal feature of the stock exchange markets.
Descrição: Published Online: 14 September 2009
<b>Tipo</b>: conferencePaper2020-02-05T10:17:13ZA kinetic model for chemical reactions without barriersKremer, Gilberto M.Soares, A. J.https://hdl.handle.net/1822/637302020-02-05T11:11:38Z2020-02-05T09:49:57ZTítulo: A kinetic model for chemical reactions without barriers
Autor: Kremer, Gilberto M.; Soares, A. J.
Resumo: A system of coupled Boltzmann equations (BE) is here proposed for a binary gaseous mixture undergoing elastic and reactive collisions. Reactive cross sections without activation energy, i.e. without barriers, are adopted to model the chemical process, whereas differential cross sections of rigid spheres are assumed for elastic scattering. The possibility of a pair of molecules to collide through an elastic mechanism or a reactive process is described by means of probability coefficients which are introduced in the collision terms. The rate of reaction and temperature exchange rate are explicitly computed using the non-equilibrium solution of the BE obtained through the Chapman-Enskog method in a chemical regime such that the reactive process is in its initial stage. Spatially homogeneous solutions are examined for the number density of reactants and mixture temperature.
Descrição: Published Online: 12 January 2009
<b>Tipo</b>: conferencePaper2020-02-05T09:49:57Z