726 research outputs found
Stochastic collocation on unstructured multivariate meshes
Collocation has become a standard tool for approximation of parameterized
systems in the uncertainty quantification (UQ) community. Techniques for
least-squares regularization, compressive sampling recovery, and interpolatory
reconstruction are becoming standard tools used in a variety of applications.
Selection of a collocation mesh is frequently a challenge, but methods that
construct geometrically "unstructured" collocation meshes have shown great
potential due to attractive theoretical properties and direct, simple
generation and implementation. We investigate properties of these meshes,
presenting stability and accuracy results that can be used as guides for
generating stochastic collocation grids in multiple dimensions.Comment: 29 pages, 6 figure
Approximation of sweep surfaces by tensor product B-splines
Journal ArticleTensor product B-spline approximations to surfaces generated by sweeping a (possibly deforming) B-spline cross-section curve along a Bspline axis curve are discussed. A general form for the tensor product B-spline approximation for sweeps is derived and expressed in terms of the approximation of a set of offset curves of the axis curve. The actual algorithm used to generate the approximation depends on the nature of the desired deformation and change in orientation that the crosssection undergoes as it is swept along the axis. Several algorithms for generating tensor product B-spline approximations to sweep surfaces are presented
BLADE: Filter Learning for General Purpose Computational Photography
The Rapid and Accurate Image Super Resolution (RAISR) method of Romano,
Isidoro, and Milanfar is a computationally efficient image upscaling method
using a trained set of filters. We describe a generalization of RAISR, which we
name Best Linear Adaptive Enhancement (BLADE). This approach is a trainable
edge-adaptive filtering framework that is general, simple, computationally
efficient, and useful for a wide range of problems in computational
photography. We show applications to operations which may appear in a camera
pipeline including denoising, demosaicing, and stylization
Nonequilibrium flow computations. 1: An analysis of numerical formulations of conservation laws
Modern numerical techniques employing properties of flux Jacobian matrices are extended to general, nonequilibrium flows. Generalizations of the Beam-Warming scheme, Steger-Warming and van Leer Flux-vector splittings, and Roe's approximate Riemann solver are presented for 3-D, time-varying grids. The analysis is based on a thermodynamic model that includes the most general thermal and chemical nonequilibrium flow of an arbitrary gas. Various special cases are also discussed
Blending techniques in Curve and Surface constructions
Source at https://www.geofo.no/geofoN.html. <p
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