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We consider embedded ring-type surfaces (that is, compact, connected, orientable surfaces with two boundary components and Euler-Poincar\'{e} characteristic zero) in ${\bold R}^3$ of constant mean curvature which meet planes $\Pi_1$ and…

Differential Geometry · Mathematics 2016-09-06 John McCuan

The Spherical Geometry Algorithm (SGA) demonstrates superior capability in achieving efficient and precise spaceborne SAR image formation processing, even under challenging imaging conditions including non-linear radar trajectories and…

Signal Processing · Electrical Eng. & Systems 2025-06-11 Xinhua Mao , Manyi Tao , Jixia Fan

We propose a new numerical algorithm to construct a structured numerical elliptic grid of a doubly connected domain. Our method is applicable to domains with boundaries defined by two contour lines of a two-dimensional function. The…

Numerical Analysis · Mathematics 2018-08-14 Matthias Wiesenberger , Markus Held , Lukas Einkemmer

Creating spherical initial conditions in smoothed particle hydrodynamics simulations that are spherically conformal is a difficult task. Here, we describe two algorithmic methods for evenly distributing points on surfaces, that when paired…

High Energy Astrophysical Phenomena · Physics 2016-04-06 Cody Raskin , J. Michael Owen

Recent microscopy imaging techniques allow to precisely analyze cell morphology in 3D image data. To process the vast amount of image data generated by current digitized imaging techniques, automated approaches are demanded more than ever.…

Computer Vision and Pattern Recognition · Computer Science 2020-10-26 Dennis Eschweiler , Malte Rethwisch , Simon Koppers , Johannes Stegmaier

To cope with the high requirements during the computation of semantic segmentations of earth observation imagery, current state-of-the-art pipelines divide the corresponding data into smaller images. Existing methods and benchmark datasets…

Computer Vision and Pattern Recognition · Computer Science 2023-06-08 Sebastian Bullinger , Florian Fervers , Christoph Bodensteiner , Michael Arens

We present a general purpose method for solving partial differential equations on a closed surface, based on a technique for discretizing the surface introduced by Wenjun Ying and Wei-Cheng Wang [J. Comput. Phys. 252 (2013), pp. 606-624]…

Numerical Analysis · Mathematics 2020-04-21 J. Thomas Beale

This paper presents a hybrid approach to spatial indexing of two dimensional data. It sheds new light on the age old problem by thinking of the traditional algorithms as working with images. Inspiration is drawn from an analogous situation…

Data Structures and Algorithms · Computer Science 2016-11-17 Lukasz A. Machowski , Tshilidzi Marwala

The problem of automated separation of stars and galaxies on photographic plates is revisited with two goals in mind : First, to separate galaxies from everything else (as opposed to most previous work, in which galaxies were lumped…

Astrophysics · Physics 2007-05-23 A. Naim

In this exploratory article, we present a constructive method for scattering points on the surface of $d$ dimensional spheres which we believe is new and of interest. Indeed, the problem of uniformly distributing points on spheres is an…

Number Theory · Mathematics 2016-10-24 Béla Bajnok , Steven B. Damelin , Jenny Li , Gary L. Mullen

Image segmentation aims to partition an image according to the objects in the scene and is a fundamental step in analysing very high spatial-resolution (VHR) remote sensing imagery. Current methods struggle to effectively consider land…

Computer Vision and Pattern Recognition · Computer Science 2024-01-08 Xianwei Lv , Claudio Persello , Wangbin Li , Xiao Huang , Dongping Ming , Alfred Stein

Image reconstruction by Algebraic Methods (AM) outperforms the transform methods in situations where the data collection procedure is constrained by time, space, and radiation dose. AM algorithms can also be applied for the cases where…

Image and Video Processing · Electrical Eng. & Systems 2022-08-30 Sudhir Kumar Chaudhary , Pankaj Wahi , Prabhat Munshi

In practice, the finite number of samples of the spherical radiation pattern or antenna gain are taken on the sphere for both the reconstruction of the antenna radiation pattern and the computation of mobile handset performance measures…

Signal Processing · Electrical Eng. & Systems 2018-12-03 Umair Ahmed , Zubair Khalid

We present a simple, accurate method for computing singular or nearly singular integrals on a smooth, closed surface, such as layer potentials for harmonic functions evaluated at points on or near the surface. The integral is computed with…

Numerical Analysis · Mathematics 2020-02-10 J. Thomas Beale , Wenjun Ying , Jason R. Wilson

Granular materials are known to separate by size under a variety of circumstances. Experiments presented here and elucidated by modeling and MD simulation document a new segregation mechanism, namely segregation by friction. The experiments…

Soft Condensed Matter · Physics 2009-11-07 L. Kondic , R. R. Hartley , S. G. K. Tennakoon , B. Painter , R. P. Behringer

We develop a new spatial semidiscrete multiscale method based upon the edge multiscale methods to solve semilinear parabolic problems with heterogeneous coefficients and smooth initial data. This method allows for a cheap spatial…

Numerical Analysis · Mathematics 2025-12-16 Leonardo A. Poveda , Shubin Fu , Guanglian Li , Eric Chung

We present a rectangle-based segmentation algorithm that sets up a graph and performs a graph cut to separate an object from the background. However, graph-based algorithms distribute the graph's nodes uniformly and equidistantly on the…

Computer Vision and Pattern Recognition · Computer Science 2012-03-14 Jan Egger , Tina Kapur , Thomas Dukatz , Malgorzata Kolodziej , Dzenan Zukic , Bernd Freisleben , Christopher Nimsky

We propose a novel method for determining the radius of a spherical surface based on the distances measured between points on this surface. We consider the most general case of determining the radius when the distances are measured with…

Computational Geometry · Computer Science 2025-04-04 Boris Sukhovilov

We propose a new class of space-filling designs called rotated sphere packing designs for computer experiments. The approach starts from the asymptotically optimal positioning of identical balls that covers the unit cube. Properly scaled,…

Methodology · Statistics 2016-08-15 Xu He

Segmentation, a useful/powerful technique in pattern recognition, is the process of identifying object outlines within images. There are a number of efficient algorithms for segmentation in Euclidean space that depend on the variational…

Computer Vision and Pattern Recognition · Computer Science 2019-11-12 Xiaohao Cai , Christopher G. R. Wallis , Jennifer Y. H. Chan , Jason D. McEwen