Results 221 to 230 of about 28,102 (266)

Triangular grids on the sphere

2022
<p class="western" align="justify">Inverting LRI data from GRACE-FO (NASA/GFZ) is challenging from  multiple points of view. To benefit from the laser instrument, that provides a higher precision compared with the KBR ranging, the global basis functions such as spherical harmonics may not ...
Josef Sebera, Aleš Bezděk, Jörg Ebbing   +2 more
openaire   +1 more source

Unstructured triangular surface grid generation and intrinsic grid analysis using rational triangular patches

Engineering Computations, 2005
PurposeTo focus on grid generation which is an essential part of any analytical tool for effective discretization.Design/methodology/approachThis paper explores the application of the possibility of unstructured triangular grid generation that deals with derivationally continuous, smooth, and fair triangular elements using piecewise polynomial ...
Sharma, R., Sha, O. P.
openaire   +2 more sources

The number of triangular islands on a triangular grid

Periodica Mathematica Hungarica, 2009
Using lattice theory, \textit{G.~Czédli} [Eur. J. Comb. 30, No 1, 208--215 (2009; Zbl 1187.05024)] has obtained a sharp upper bound for the number of rectangular islands. His methods are applied in the paper under review to estimate the number \(f(n)\) of triangular islands on a triangular grid with the side length \(n\): \((n^2 + 3n)/5 \leq f(n) \leq (
Horváth, Eszter K., Németh, Zoltán, Pluhár, Gabriella   +2 more
openaire   +2 more sources

Finite differences on triangular grids

Numerical Methods for Partial Differential Equations, 1998
A finite difference method is defined on a triangular grid for the Dirichlet problem of the Poisson equation. A relation between this finite difference scheme and the finite element method is given. From this new point of view the properties (maximum principle) of the solution and convergence are analyzed.
Brighi, B, Chipot, M, Gut, E
openaire   +3 more sources

Quantization error in regular grids: triangular pixels

IEEE Transactions on Image Processing, 1998
Quantization of the image plane into pixels results in the loss of the true location of features within pixels and introduces an error in any quantity computed from feature positions in the image. We derive closed-form, analytic expressions for the error distribution function, the mean absolute error (MAE), and the mean square error (MSE) due to ...
B. Kamgar-Parsi, B. Kamgar-Parsi
openaire   +2 more sources

Algebraic multigrid / substructuring preconditioners on triangular grids

Russian Journal of Numerical Analysis and Mathematical Modelling, 1991
Summary: A new approach to constructing algebraic multigrid preconditioners for the mesh diffusion operators suggested and studied before by one of the authors for the case of square grids is extended to include the case of triangular hierarchical grids.
Hakopian, Yu. R., Kuznetsov, Yu. A.
openaire   +2 more sources

Finite-Difference Schemes on Regular Triangular Grids

Journal of Computational Physics, 1993
The authors consider wave propagation errors of linear convection equations in one and two spatial dimensions (1) \(U_ t + c \cdot \text{grad} U = 0\). For the analytical solution an ansatz of harmonic functions is made. This is compared with some numerical semidiscrete approximations of (1). In the 2D-case finite difference schemes are considered on a
Zingg, David W., Lomax, Harvard
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Topology preservation on the triangular grid

Annals of Mathematics and Artificial Intelligence, 2014
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Kardos, Péter, Palágyi, Kálmán
openaire   +2 more sources

Binary Tomography on Triangular Grid Involving Hexagonal Grid Approach

2018
In this paper, we consider the binary tomography reconstruction problem of images on the triangular grid. The reconstruction process is based on three natural directions of projections, defined by the lane directions of the triangular grid (they are analogous to row and column directions on the square grid).
Benedek Nagy, Tibor Lukić
openaire   +1 more source

Parallel thinning on the triangular grid

2013 IEEE 4th International Conference on Cognitive Infocommunications (CogInfoCom), 2013
One of the fundamental issues of human and computational cognitive psychology is pattern or shape recognition. Various applications in image processing and computer vision rely on skeleton-like shape features A possible technique for extracting these feautures is thinning. Although the majority of 2D thinning algorithms work on digital pictures sampled
Kardos Péter, Palágyi Kálmán
openaire   +2 more sources