Results 31 to 40 of about 169,552 (158)

Numerical-Well-Testing Interpretation of Injection/Falloff Testing for Coalbed Methane Well in Hedong Coalfield

Energies, 2023
Numerical well testing is used mostly in oil/gas, geothermal, and coalbed methane injection/falloff well-testing interpretations while few published studies have been presented on how to adjust the models and numerical experiments parameters.
Shiyue Fang, Xujing Zhang, Xinzhan Li, Yue Chen, Baiyi He, Yuan Bao, Dongmin Ma   +6 more
doaj   +1 more source

High order approximation of degree nine and order eighteen

Journal of Inequalities and Applications, 2019
In this paper, a method to approximate curves by polynomials of degree nine is presented. The resulting approximation has order eighteen. The method is applied to approximate a circular arc, and the error function is studied and characterized, and its ...
Abedallah Rababah
doaj   +1 more source

Degree of approximation of continuous functions by some singular integrals

Journal of Numerical Analysis and Approximation Theory, 1998
The main aim of this paper is to obtain error bounds in terms of higher order moduli of smoothness, for approximation by singular integrals of Picard, Poisson-Cauchy and Gauss-Weierstrass type.
Sorin G. Gal
doaj   +2 more sources

The Kantorovich form of some extensions for the Szász-Mirakjan operators

Journal of Numerical Analysis and Approximation Theory, 2010
Recently, C. Mortici defined a class of linear and positive operators depending on a certain function \(\varphi\). These operators generalize the well known Szász-Mirakjan operators.
Dan Bărbosu, Ovidiu T. Pop, Dan Miclăuş   +2 more
doaj   +2 more sources

Degree of approximation of genuine Lupaş-Durrmeyer operators

Tbilisi Mathematical Journal, 2019
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Manav, Nesibe, Ispir, Nurhayat
openaire   +3 more sources

The degree of coconvex polynomial approximation [PDF]

Proceedings of the American Mathematical Society, 1999
The paper deals with the degree of coconvex polynomial approximation. The main result is as follows: Theorem.
Kopotun, K., Leviatan, D., Shevchuk, I. A.   +2 more
openaire   +2 more sources

On the rate of convergence of Baskakov-Kantorovich-Bézier operators for bounded variation functions

Journal of Numerical Analysis and Approximation Theory, 2002
In the present paper we introduce Baskakov-Kantorovich-Bézier operators and study their rate of convergence for functions of bounded variation.
Ulrich Abel, Vijay Gupta, Mircea Ivan
doaj   +2 more sources

Numerical integration by the matrix method and evaluation of the approximation order of difference boundary value problems for non-homogeneous linear ordinary differential equations of the fourth order with variable coefficients

Vestnik Samarskogo Gosudarstvennogo Tehničeskogo Universiteta. Seriâ: Fiziko-Matematičeskie Nauki, 2020
The use of the second degree Taylor polynomial in approximation of derivatives by finite difference method leads to the second order approximation of the traditional grid method for numerical integration of boundary value problems for non-homogeneous ...
Vladimir Nikolaevich Maklakov, Mariya Aleksandrovna Ilicheva   +1 more
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On the degree of approximation by Gauss Weierstrass integrals

International Journal of Mathematics and Mathematical Sciences, 2000
We obtain the degree of approximation of functions belonging to class Lip(ψ(u,v);p),   p>1 using the Gauss Weierstrass integral of the double Fourier series of f(x,y).
Huzoor H. Khan, Govind Ram
doaj   +1 more source

The evaluation of the order of approximation of the matrix method for numerical integration of the boundary value problems for systems of linear non-homogeneous ordinary differential equations of the second order with variable coefficients. Message 1. Boundary value problems with boundary conditions of the first kind

Vestnik Samarskogo Gosudarstvennogo Tehničeskogo Universiteta. Seriâ: Fiziko-Matematičeskie Nauki, 2016
We present the first message of the cycle from two articles where the rearrangement of the order of approximation of the matrix method of numerical integration depending on the degree in the Taylor’s polynomial expansion of solutions of boundary value ...
Vladimir N Maklakov
doaj   +1 more source