Τμήμα Μαθηματικών και Στατιστικής / Department of Mathematics and Statistics: Recent submissions
Now showing items 61-80 of 1633
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Article
Variable shape parameter Kansa RBF method for the solution of nonlinear boundary value problems
(2019)We apply a variable shape parameter Kansa–radial basis function (RBF) collocation method for the numerical solution of second and fourth order nonlinear boundary value problems in two dimensions. In the current approach, ...
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Article
Signals Featuring Harmonics with Random Frequencies -- Spectral, Distributional and Ergodic Properties
(2019)It has been observed that an interesting class of non-Gaussian stationary processes is obtained when in the harmonics of a signal with random amplitudes and phases, frequencies can also vary randomly. In the resulting ...
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Article
Local RBF Algorithms for Elliptic Boundary Value Problems in Annular Domains
(2019)A local radial basis function method (LRBF) is applied for the solution of boundary value problems in annular domains governed by the Poisson equation, the inhomogeneous biharmonic equation and the inhomogeneous Cauchy-Navier ...
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Article
Kansa RBF method for nonlinear problems
(2018)We apply the Kansa–radial basis function (RBF) collocation method to two– dimensional nonlinear boundary value problems. The system of nonlinear equations resulting from the Kansa–RBF discretization is solved by directly ...
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Conference Object
On Generalized Stieltjes functions and their approximations
(University of Aegean, 2018)
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Article
Kansa-RBF algorithms for elliptic problems in regular polygonal domains
(2018)We propose matrix decomposition algorithms for the efficient solution of the linear systems arising from Kansa radial basis function discretizations of elliptic boundary value problems in regular polygonal domains. These ...
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Article
The method of fundamental solutions for the identification of a scatterer with impedance boundary condition in interior inverse acoustic scattering
(2018)We employ the method of fundamental solutions (MFS) for detecting a scatterer surrounding a host acoustic homogeneous medium D due to a given point source inside it. On the boundary of the unknown scatterer (assumed to be ...
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Article
Reconstruction of an elliptical inclusion in the inverse conductivity problem
(2018)This study reports on a numerical investigation into the open problem of the unique reconstruction of an elliptical inclusion in the potential field from a single set of nontrivial Cauchy data. The investigation is based ...
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Article
A Legendre spectral quadrature Galerkin method for the Cauchy-Navier equations of elasticity with variable coefficients
(2018)We solve the Dirichlet and mixed Dirichlet-Neumann boundary value problems for the variable coefficient Cauchy-Navier equations of elasticity in a square using a Legendre spectral Galerkin method. The resulting linear ...
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Article
Improved Kansa RBF method for the solution of nonlinear boundary value problems
(2018)We apply the Kansa–radial basis function (RBF) collocation method to two-dimensional nonlinear boundary value problems. In it, the solution is approximated by a linear combination of RBFs and the governing equation and ...
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Article
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Article
Extending the Range of Validity of the Autoregressive (Sieve) Bootstrap
(2018)Two modifications of the autoregressive‐sieve and of the autoregressive bootstrap are proposed. The first modification replaces the classical i.i.d. resampling scheme applied to the residuals of the autoregressive fit by ...
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Article
On Generalized Stieltjes Functions
(2019)It is shown that a function f is a generalized Stieltjes function of order $$\lambda >0$$λ>0if and only if $$x^{1-\lambda }(x^{\lambda -1+k}f(x))^{(k)}$$x1-λ(xλ-1+kf(x))(k)is completely monotonic for all $$k\ge 0$$k≥0, ...
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Article
Estimated Wold representation and spectral-density-driven bootstrap for time series
(2018)The second-order dependence structure of purely non-deterministic stationary processes is described by the coefficients of the famous Wold representation. These coefficients can be obtained by factorizing the spectral ...
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Article
A Frequency Domain Bootstrap for General Stationary Processes
(2018)Existing frequency domain methods for bootstrapping time series have a limited range. Consider for instance the class of spectral mean statistics (also called integrated periodograms) which includes many important statistics ...
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Article
Poisson Brackets after Jacobi and Plücker
(2018)We construct a symplectic realization and a bi-Hamiltonian formulation of a 3-dimensional system whose solution are the Jacobi elliptic functions. We generalize this system and the related Poisson brackets to higher ...
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Conference Object
A Sieve Bootstrap Method that Incorporates Model Uncertainty for Constructing Prediction Intervals for Functional Time Series
(Springer, 2019)
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Article
Sieve bootstrap for functional time series
(2018)A bootstrap procedure for functional time series is proposed which exploits a general vector autoregressive representation of the time series of Fourier coefficients appearing in the Karhunen–Loève expansion of the functional ...
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Article
Locally Explicit Fundamental Principle for Homogeneous Convolution Equations
(2019)In the present paper a locally explicit version of Ehrenpreis's Fundamental Principle for a system of homogeneous convolution equations f · µj = 0, j = 1, ..., m, f ∈ E(Rn), µj ∈ E' (Rn), is derived, when the Fourier ...
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Article
Mixture of Truthful–Untruthful Responses in Public Surveys
(2019)When sensitive issues are surveyed, collecting truthful data and obtaining reliable estimates of population parameters is a persistent problem in many fields of applied research mostly in sociological, economic, demographic, ...