Results 51 to 60 of about 377,631 (158)

A general positivity-preserving algorithm for implicit high-order finite volume schemes solving the Euler and Navier-Stokes equations

, 2023
This paper presents a general positivity-preserving algorithm for implicit high-order finite volume schemes solving Euler and Navier-Stokes equations.
Ren, Yu-Xin, Wang, Qian, Huang, Qian-Min
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Numerical Testing of a New Positivity-Preserving Interpolation Algorithm

, 2022
An important component of a number of computational modeling algorithms is an interpolation method that preserves the positivity of the function being interpolated. This report describes the numerical testing of a new positivity-preserving algorithm that
Kirby, Robert M., Berzins, Martin, Ouermi, T. A. J.   +2 more
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On positivity preservation for free quantum fields

Journal of Mathematical Analysis and Applications, 1975
AbstractLet A be a real Bose or Fermi one-particle operator with ∥ A ∥ ⩽ I. Using Kaplansky's density theorem, a simple proof is given of the fact that Γ(A), the operator in Fock space induced by A, is positivity preserving in the relevant L2-space.
Perez, J.Fernando, Wilde, Ivan F
openaire   +1 more source

On positivity preservers with constant coefficients and their generators

Journal of Algebra
In this work we study positivity preservers $T:\mathbb{R}[x_1,\dots,x_n]\to\mathbb{R}[x_1,\dots,x_n]$ with constant coefficients and define their generators $A$ if they exist, i.e., $\exp(A) = T$. We use the theory of regular Fréchet Lie groups to show the first main result.
openaire   +2 more sources

Entropy dissipative higher order accurate positivity preserving time-implicit discretizations for nonlinear degenerate parabolic equations [PDF]

We develop entropy dissipative higher order accurate local discontinuous Galerkin (LDG) discretizations coupled with Diagonally Implicit Runge–Kutta (DIRK) methods for nonlinear degenerate parabolic equations with a gradient flow structure.
Xu, Yan, Van der Vegt, J. J.W.; id_orcid, Xia, Yinhua, Yan, Fengna   +3 more
core   +1 more source

Positivity Preserving Schemes for Black-Scholes Equation

, 2015
Mathematical finance is a field of applied mathematics, concerned with financial markets. In the market of financial derivatives the most important problem is the so called option valuation problem, i.e. to compute a fair value for the option.
Jahandizi, Reza Shokri, Khalsaraei, Mohammad Mehdizadeh   +1 more
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Privacy-Preserving Profiling

, 2011
With the rise of social networking, and other sites which collect vast amounts of user data, the issue of user privacy has never been more important. When creating user profiles care must be taken to avoid collecting sensitive information, while ensuring
Barnard, Thomas, Prugel-Bennett, Adam
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Gas-kinetic schemes for the compressible Euler equations: Positivity-preserving analysis

, 1999
Numerical schemes based on the collisional BGK model have been developed in recent years. In this paper, we investigate the first-order BGK schemes for the Euler equations.
Xu, Kun, Tang, Tao
core   +1 more source

Positivity Preserving Numerical Schemes For Lubrication-Type Equations

, 1998
. Lubrication equations are fourth order degenerate diffusion equations of the form h t + r \Delta (f(h)r\Deltah) = 0, describing thin films or liquid layers driven by surface tension. Recent studies of singularities in which h ! 0 at a point, describing
L. Zhornitskaya, A.L. Bertozzi
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Positivity-preserving finite volume methods for compressible Navier-Stokes equations

, 2017
In this thesis, we discuss first and second order finite volume methods to solve the one dimensional compressible Navier-Stokes equations. We prove the first order finite volume method preserves positivity for the density and pressure.
Muchowski, Heather
core   +1 more source