Search Results - "Duarte Ortigueira, Manuel"

Fractional Derivatives: The Perspective of System Theory by Duarte Ortigueira, Manuel, Tenreiro Machado, José

“…This paper addresses the present day problem of multiple proposals for operators under the umbrella of “fractional derivatives”. Several papers demonstrated…”
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Revisiting the 1D and 2D Laplace Transforms by Duarte Ortigueira, Manuel, Tenreiro Machado, José

“…The paper reviews the unilateral and bilateral, one- and two-dimensional Laplace transforms. The unilateral and bilateral Laplace transforms are compared in…”
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Automatic Contraction Detection Using Uterine Electromyography by Esgalhado, Filipa, Batista, Arnaldo G., Mouriño, Helena, Russo, Sara, dos Reis, Catarina R. Palma, Serrano, Fátima, Vassilenko, Valentina, Duarte Ortigueira, Manuel

“…Electrohysterography (EHG) is a promising technique for pregnancy monitoring and preterm risk evaluation. It allows for uterine contraction monitoring as early…”
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Two‐sided and regularised Riesz‐Feller derivatives by Ortigueira, Manuel Duarte

“…The two‐sided derivatives, the Riesz‐Feller potentials, and their interrelations are studied in this paper. A general integral formulation for two‐sided…”
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Discrete-Time Fractional Difference Calculus: Origins, Evolutions, and New Formalisms by Ortigueira, Manuel Duarte

“…Differences are introduced as outputs of linear systems called differencers, being considered two classes: shift and scale-invariant. Several types are…”
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An Entropy Paradox Free Fractional Diffusion Equation by Ortigueira, Manuel Duarte

“…A new look at the fractional diffusion equation was done. Using the unified fractional derivative, a new formulation was proposed, and the equation was solved…”
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Bilateral Tempered Fractional Derivatives by Ortigueira, Manuel Duarte, Bengochea, Gabriel

“…The bilateral tempered fractional derivatives are introduced generalising previous works on the one-sided tempered fractional derivatives and the two-sided…”
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Editorial for Special Issue “Fractional Behavior in Nature 2019” by Ortigueira, Manuel Duarte

“…The presence of fractional behavior in nature is unquestionable [...]…”
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A Simple Solution for the General Fractional Ambartsumian Equation by Ortigueira, Manuel Duarte, Bengochea, Gabriel

“…Fractionalisation and solution of the Ambartsumian equation is considered. The general approach to fractional calculus suitable for applications in physics and…”
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RIESZ POTENTIAL OPERATORS AND INVERSES VIA FRACTIONAL CENTRED DERIVATIVES by Ortigueira, Manuel Duarte

“…Fractional centred differences and derivatives definitions are proposed, generalizing to real orders the existing ones valid for even and odd positive integer…”
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A coherent approach to non-integer order derivatives by Ortigueira, Manuel Duarte

“…The relation showing that the Grünwald-Letnikov and generalised Cauchy derivatives are equal is presented. This establishes a bridge between two different…”
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On Lebesgue Constants by Ortigueira, Manuel Duarte, Bengochea, Gabriel

“…Simple formulae for Lebesgue constants arising in the classical Fourier series approximation are obtained. Both even and odd cases are addressed, extending…”
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On the Fractional Derivative Duality in Some Transforms by Ortigueira, Manuel Duarte, Bengochea, Gabriel

“…Duality is one of the most interesting properties of the Laplace and Fourier transforms associated with the integer-order derivative. Here, we will generalize…”
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On the Equivalence between Integer- and Fractional Order-Models of Continuous-Time and Discrete-Time ARMA Systems by Ortigueira, Manuel Duarte, Magin, Richard L.

“…The equivalence of continuous-/discrete-time autoregressive-moving average (ARMA) systems is considered in this paper. For the integer-order cases, the…”
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An Operational Approach to Fractional Scale-Invariant Linear Systems by Bengochea, Gabriel, Ortigueira, Manuel Duarte

“…The fractional scale-invariant systems are introduced and studied, using an operational formalism. It is shown that the impulse and step responses of such…”
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A New Look at the Capacitor Theory by Ortigueira, Manuel Duarte, Martynyuk, Valeriy, Kosenkov, Volodymyr, Batista, Arnaldo Guimarães

“…The mathematical description of the charging process of time-varying capacitors is reviewed and a new formulation is proposed. For it, suitable fractional…”
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A Review of Sample and Hold Systems and Design of a New Fractional Algorithm by Ortigueira, Manuel Duarte, Machado, José Tenreiro

“…Digital systems require sample and hold (S&H) systems to perform the conversion from analog to digital and vice versa. Besides the standard zero and first…”
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Fractional calculus applications in signals and systems by Ortigueira, Manuel Duarte, Machado, J.A. Tenreiro

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Fractional signal processing and applications by Duarte Ortigueira, Manuel, Tenreiro Machado, J.A

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A Fractional Linear System View of the Fractional Brownian Motion by Ortigueira, Manuel Duarte, Batista, Arnaldo Guimar es

“…A definition of the fractional Brownian motion based on the fractional differintegrator characteristics is proposed and studied. It is shown that the model…”
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