Fitting Constrained Continuous Spline Curves. [PDF]
, 2003 Fitting a curve through a set of planar data which represents a positive quantity requires that the curve stays above the horizontal axis, The more general problem of designing parametric and non-parametric curves which do not cross the given constraint
Ong, B. H., Kong, V.P.
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Preservation of positivity by dynamical coarse graining [PDF]
Physical Review A, 2008 18 pages, 7 figures, reviewers suggestions included and tightened presentation; accepted for publication in ...
Schaller, Gernot, Brandes, Tobias
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Positivity Preserving Multiapproximation
American Journal of Scientific and Industrial Research, 2012 We show that the degree of copositive multipolynomial approximation to a function which changes signs finitely many times in , can be estimated by ...
Eman Bhaya, Mayada Ali
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Ergodic semigroups of positivity preserving self-adjoint operators [PDF]
, 1973 We prove that an ergodic semigroup of positivity preserving self-adjoint operators is positivity improving. We also present a new proof (using Markov techniques) of the ergodicity of semigroups generated by spatially cutoff P(ϑ)2 ...
Simon, Barry
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Positivity and Monotonicity Preserving Biquartic Rational Interpolation Spline Surface
Journal of Applied Mathematics, 2014 A biquartic rational interpolation spline surface over rectangular domain is constructed in this paper, which includes the classical bicubic Coons surface as a special case.
Xinru Liu, Yuanpeng Zhu, Shengjun Liu
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Positivity Preserving Limiters for Time-Implicit Higher Order Accurate Discontinuous Galerkin Discretizations [PDF]
, 2019 Currently, nearly all positivity preserving discontinuous Galerkin (DG) discretizations of partial differential equations are coupled with explicit time integration methods.
van der Vegt, J.J.W.; id_orcid +3 more
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Positivity-preserving strategies and their comparision based on staggered CPR methods
Kongqi donglixue xuebaoHigh-order accurate algorithms often encounter numerical instabilities, such as negative density or pressure, when simulating flow fields with strong discontinuities, extremely low density, or low pressure.
Weizhe Wang +3 more
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On the Completely Positive and Positive Semidefinite-Preserving Cones—Part III [PDF]
ISRN Algebra, 2012 This paper studies the extremals and other faces of the completely positive and positive semidefinite-preserving linear transformations.
Andrew J. Klimas, Richard D. Hill
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Efficient Positivity-Preserving NSFD Scheme: Application to Advection-Diffusion-Reaction Equation [PDF]
Journal of Applied and Computational MechanicsSolving problems across a wide range of scientific and engineering domains, encompassing physical, mechanical and biological systems as well as financial markets, necessitates addressing parabolic equations of the advection-diffusion-reaction (ADR ...
Reza Shokri Jahandizi +3 more
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\({K}\)-Positivity Preservers and Their Generators
SIAM Journal on Applied Algebra and GeometryWe study $K$-positivity preservers with given closed $K\subseteq\mathbb{R}^n$, i.e., linear maps $T:\mathbb{R}[x_1,\dots,x_n]\to\mathbb{R}[x_1,\dots,x_n]$ such that $T\mathrm{Pos}(K)\subseteq\mathrm{Pos}(K)$ holds, and their generators $A:\mathbb{R}[x_1,\dots,x_n]\to\mathbb{R}[x_1,\dots,x_n]$, i.e., $e^{tA}\mathrm{Pos}(K)\subseteq\mathrm{Pos}(K)$ holds
Philipp Di Dio, Konrad Schmüdgen
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