J. Morais

ORCID: 0000-0001-7045-0224
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About
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Research Areas
  • Algebraic and Geometric Analysis
  • Mathematical Analysis and Transform Methods
  • Holomorphic and Operator Theory
  • Mathematics and Applications
  • Analytic and geometric function theory
  • Advanced Topics in Algebra
  • Matrix Theory and Algorithms
  • Image and Signal Denoising Methods
  • Advanced Differential Geometry Research
  • Elasticity and Wave Propagation
  • Geophysics and Sensor Technology
  • Nonlinear Waves and Solitons
  • Seismic Imaging and Inversion Techniques
  • advanced mathematical theories
  • Advanced Mathematical Theories and Applications
  • Quantum Mechanics and Non-Hermitian Physics
  • Digital Filter Design and Implementation
  • Antiplatelet Therapy and Cardiovascular Diseases
  • Advanced Mathematical Modeling in Engineering
  • Homotopy and Cohomology in Algebraic Topology
  • Differential Equations and Boundary Problems
  • Water Quality Monitoring Technologies
  • Advanced Numerical Analysis Techniques
  • Noncommutative and Quantum Gravity Theories
  • Digital Transformation in Industry

University of Aveiro
2012-2024

Instituto Tecnológico Autónomo de México
2015-2024

Instituto Politécnico de Leiria
2013-2024

Instituto de Telecomunicações
2024

University of Macau
2012-2016

TU Bergakademie Freiberg
2010-2012

Bauhaus-Universität Weimar
2007-2011

We generalize the linear canonical transform (LCT) to quaternion-valued signals, known as quaternionic (QLCT). Using properties of LCT we establish an uncertainty principle for QLCT. This prescribes a lower bound on product effective widths signals in spatial and frequency domains. It is shown that only 2D Gaussian signal minimizes uncertainty.

10.1155/2013/725952 article EN cc-by Abstract and Applied Analysis 2013-01-01

Prolate spheroidal wave functions (PSWFs) possess many remarkable properties. They are orthogonal basis of both square integrable space finite interval and the Paley–Wiener bandlimited on real line. No other system classical is known to obey this unique property. This raises question whether they these properties in Clifford analysis. The aim article answer extend results more flexible integral transforms, such as offset linear canonical transform. We also illustrate how use generalized...

10.1002/mma.2657 article EN Mathematical Methods in the Applied Sciences 2012-08-13

In the present paper, we generalize linear canonical transform (LCT) to quaternion‐valued signals, known as quaternionic LCT (QLCT). Using properties of LCT, establish an uncertainty principle for two‐sided QLCT. This prescribes a lower bound on product effective widths signals in spatial and frequency domains. It is shown that only Gaussian signal minimizes uncertainty. Copyright © 2016 John Wiley & Sons, Ltd.

10.1002/mma.3724 article EN Mathematical Methods in the Applied Sciences 2016-02-09

Models of our universe lack consistency at different energy scales, so we require a theory with ultraviolet (UV) completion such as string theory. A suitable candidate to model in this framework is de Sitter space, spacetime which expands and has positive curvature. When describing the expansion however, one computes wrong sign for cosmological constant that would not allow an expanding universe. This motivates consider corrections from quantum reproduce correct constant. The conditions...

10.26443/msurj.v1i1.337 article EN cc-by McGill Science Undergraduate Research Journal 2025-03-31

The main goal of this article is to generalize Hadamard's real part theorem and invariant forms Borel–Carathéodory's from complex analysis solutions the Riesz system in three-dimensional Euclidean space framework quaternionic analysis.

10.1080/17476933.2010.504838 article EN Complex Variables and Elliptic Equations 2011-02-10

10.1007/s11045-016-0410-7 article EN Multidimensional Systems and Signal Processing 2016-04-09

In recent years, much attention has been paid to the role of classical special functions a real or complex variable in mathematical physics, especially boundary value problems (BVPs). present paper, we propose higher‐dimensional analogue generalized Bessel polynomials within Clifford analysis via set monogenic polynomials. We give definition and derive number important properties (GMBPs), which are defined by generating exponential function shown satisfy an Rodrigues' formula. As...

10.1002/mma.5274 article EN Mathematical Methods in the Applied Sciences 2018-11-08

The autonomous identification of animal births has a significant added value, since it enables for prompt timely human intervention in the process, protecting young and mothers’ health, without requiring continuous surveillance. Wearable inertial sensors have been employed variety monitoring applications, thanks to their low cost fact that they allow less invasive process. Alarms triggered by occurrence events must be generated close avoid delays caused communication latency, which is why...

10.3390/ani14060938 article EN cc-by Animals 2024-03-19

10.1007/bf03321749 article EN Computational Methods and Function Theory 2009-06-01

10.1016/j.camwa.2012.10.011 article EN publisher-specific-oa Computers & Mathematics with Applications 2012-12-06

The main goal of this paper is to construct Orthogonal Appell systems polynomial solutions the Riesz and Moisil-Théodoresco in finite cylinders ℝ3. This will be done spaces square integrable functions over ℝ ℍ. Some important properties are discussed. Copyright © 2011 John Wiley & Sons, Ltd.

10.1002/mma.1457 article EN Mathematical Methods in the Applied Sciences 2011-04-19

10.1016/j.jmaa.2013.10.068 article EN publisher-specific-oa Journal of Mathematical Analysis and Applications 2013-10-28

The paper aims to study differential subordination and superordination preserving properties for certain analytic multivalent functions within the open unit disk related a novel generalized fractional derivative operator higher-order derivatives. As an application, we provide explicit construction complex potential (the velocity) stream function of two-dimensional fluid flow problems over circular cylinder using both vortex source/sink. We further determine produced by single source...

10.1016/j.aej.2021.02.037 article EN cc-by-nc-nd Alexandria Engineering Journal 2021-03-09

A function from a domain in to the quaternions is said be inframonogenic if , where . All functions are biharmonic. In context of taking values reduced quaternions, we show that homogeneous polynomials degree form subspace dimension We use construct an explicit, computable orthogonal basis for Hilbert space square‐integrable defined ball

10.1002/mma.9600 article EN Mathematical Methods in the Applied Sciences 2023-08-07

10.1016/j.mcm.2012.06.020 article EN publisher-specific-oa Mathematical and Computer Modelling 2012-07-20

We construct of a family fundamental solutions for elliptic partial differential operators with real constant coefficients. The elements such are expressed by means jointly analytic functions the coefficients and spatial variable. show regularity properties in frame Schauder spaces corresponding single layer potentials.

10.1002/mma.2706 article EN Mathematical Methods in the Applied Sciences 2012-12-06

10.1007/bf03321843 article EN Computational Methods and Function Theory 2012-08-21

The windowed Fourier transform replaces the transform's sinusoidal wave by product of a sinusoid and window which is localized in time. It has been shown to represent powerful tool for non-stationary signals time-varying systems. In present paper, we investigate uncertainty principles short-time spectral domain. Two sharper complex are proposed. tighter lower bounds related covariance time frequency, can be achieved chirp with Gaussian envelope. results presented this paper explain...

10.1080/09500340.2014.952692 article EN Journal of Modern Optics 2014-09-03
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