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Fractal-classic interpolants

M. A. Navascués, M. V. Sebastián (2009)

Banach Center Publications

The methodology of fractal interpolation is very useful for processing experimental signals in order to extract their characteristics of complexity. We go further and prove that the Iterated Function System involved may also be used to obtain new approximants that are close to classical ones. In this work a classical function and a fractal function are combined to construct a new interpolant. The fractal function is first defined as a perturbation of a classical mapping. The additional condition...

Functions of bounded variation, signed measures, and a general Koksma-Hlawka inequality

Christoph Aistleitner, Josef Dick (2015)

Acta Arithmetica

We prove a correspondence principle between multivariate functions of bounded variation in the sense of Hardy and Krause and signed measures of finite total variation, which allows us to obtain a simple proof of a generalized Koksma-Hlawka inequality for non-uniform measures. Applications of this inequality to importance sampling in Quasi-Monte Carlo integration and tractability theory are given. We also discuss the problem of transforming a low-discrepancy sequence with respect to the uniform measure...

Further convergence results for two quadrature rules for Cauchy type principal value integrals

Nikolaos I. Ioakimidis (1982)

Aplikace matematiky

New convergence and rate-of-convergence results are established for two well-known quadrature rules for the numerical evaluation of Cauchy type principal value integrals along a finite interval, namely the Gauss quadrature rule and a similar interpolatory quadrature rule where the same nodes as in the Gauss rule are used. The main result concerns the convergence of the interpolatory rule for functions satisfying the Hölder condition with exponent less or equal to 1 2 . The results obtained here supplement...

Generació adaptativa de contorns de nivell.

Lluis Pérez Vidal, Pere Brunet Crosa (1987)

Qüestiió

La elaboración de mapas que incluyen contornos de nivel se hace a partir de un conjunto de puntos dados por sus coordenadas. Existen varias formulaciones analíticas para definir una función de interpolación. En este artículo se propone una variante de la formulación de Little que puede servir para mejorar localmente su funcionamiento. Con objeto de estudiar su rendimiento se describen las alternativas presentes con cuatro ejemplos.

Generalized Kronrod Patterson type imbedded quadratures

Sylvan Elhay, Jaroslav Kautský (1992)

Applications of Mathematics

We present algorithms for the determination of polynomials orthogonal with respect to a positive weight function multiplied by a polynomial with simple roots inside the interval of integration. We apply these algorithms to search for and calculate all possible sequences of imbedded quadratures of maximal polynomials order of precision for the generalized Laguerre and Hermite weight functions.

Generalized method of least squares collocation

Ludmila Kubáčková, Lubomír Kubáček (1982)

Aplikace matematiky

Two general solutions of the collocation problem of physical geodesy are given. Their mutual equivalency and equivalency of them to the classical solution in the regular case are proved. The regularity means the non-singularity of the covariance matrix of those random variables by outcomes of which the measured values of the gravitational field are generated.

Geodesic metrics for RBF approximation of some physical quantities measured on sphere

Karel Segeth (2024)

Applications of Mathematics

The radial basis function (RBF) approximation is a rapidly developing field of mathematics. In the paper, we are concerned with the measurement of scalar physical quantities at nodes on sphere in the 3D Euclidean space and the spherical RBF interpolation of the data acquired. We employ a multiquadric as the radial basis function and the corresponding trend is a polynomial of degree 2 considered in Cartesian coordinates. Attention is paid to geodesic metrics that define the distance of two points...

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