Publications related to Geodesics on an ellipsoid

Verification of selective laser melting heat source models with operando X-ray diffraction data

Helena Van Swygenhoven, Steven Van Petegem, Samy Hocine

The output obtained from operando X-ray diffraction experiments on Ti-6Al-4V is used to verify the accuracy of four FEM models in predicting the temperature evolution of the solidified domain, the cooling rates of the alpha and beta phases, and the influen ...

ELSEVIER2021

Generation of elastic geodesic gridshells with anisotropic cross sections

Corentin Jean Dominique Fivet, Nicolas Robin Montagne, Olivier Baverel

Geodesic gridshells are shell structures made of continuous elements following geodesic lines. Their properties ease the use of beams with anisotropic cross-sections by avoiding bending about their strong axis. However, such bending may arise when flatteni ...

2021

Voss surfaces: A design space for geodesic gridshells

Corentin Jean Dominique Fivet, Nicolas Robin Montagne, Olivier Baverel

The design of envelopes with complex geometries often leads to construction challenges. To overcome these difficulties, resorting to discrete differential geometry proved successful by establishing close links between mesh properties and the existence of g ...

2021

Energy distribution of harmonic 1-forms and Jacobians of Riemann surfaces with a short closed geodesic

Jürgpeter Buser, Robert Silhol

We study the energy distribution of harmonic 1-forms on a compact hyperbolic Riemann surface S where a short closed geodesic is pinched. If the geodesic separates the surface into two parts, then the Jacobian variety of S develops into a variety that split ...

2021

Geodesic flows on real forms of complex semi-simple Lie groups of rigid body type

Tudor Ratiu

The geodesic flows are studied on real forms of complex semi-simple Lie groups with respect to a left-invariant (pseudo-)Riemannian metric of rigid body type. The Williamson types of the isolated relative equilibria on generic adjoint orbits are determined ...

SPRINGER INTERNATIONAL PUBLISHING AG2020

Microstructural controls of anticrack nucleation in highly porous brittle solids

Johan Alexandre Philippe Gaume, Henning Löwe, Jonas Ritter

Porous brittle solids have the ability to collapse and fail even under compressive stresses. In fracture mechanics, this singular behavior, often referred to as anticrack, demands for appropriate continuum models to predict the catastrophic failure. To ide ...

Nature Research2020

Voss Surfaces: A Design Space for Geodesic Gridshells

Corentin Jean Dominique Fivet, Nicolas Robin Montagne, Olivier Baverel

The design of envelopes with complex geometries often leads to construction challenges. To overcome these difficulties, resorting to discrete differential geometry proved successful by establishing close links between mesh properties and the existence of g ...

2020

Comparison-Based Optical Assessment of Hyperboloid and Ellipsoid Reflectors in a Beam-Down Solar Tower System With Linear Fresnel Heliostats

Meng Lin

Beam-down concentrating solar tower (BCST) is known for its merits in easy installation and maintenance as well as lower convection heat loss of the central receiver (CR) when comparing to a traditional concentrated solar tower system. A point-line-couplin ...

ASME2017

On a Lagrangian Formulation of the Incompressible Euler Equation

Hasan Inci

In this paper we show that the incompressible Euler equation on the Sobolev space H-s(R-n), s> n/2+1, can be expressed in Lagrangian coordinates as a geodesic equation on an infinite dimensional manifold. Moreover the Christoffel map describing the geodesi ...

Global Science Press2016

The geometry of the universal Teichmuller space and the Euler-Weil-Petersson equation

Tudor Ratiu, François Gay-Balmaz

On the identity component of the universal Teichmuller space endowed with the Takhtajan-Teo topology, the geodesics of the Weil Petersson metric are shown to exist for all time. This component is naturally a subgroup of the quasisymmetric homeomorphisms of ...

Elsevier2015

Stability Results For The Volume Of Random Simplices

Gergely Ambrus

It is known that for a convex body K in R-d of volume one, the expected volume of random simplices in K is minimized if K is an ellipsoid, and for d = 2, maximized if K is a triangle. Here we provide corresponding stability estimates. ...

Johns Hopkins Univ Press2014

Constructing reparameterization invariant metrics on spaces of plane curves

Martins Bruveris, Martin Bauer

Metrics on shape spaces are used to describe deformations that take one shape to another, and to define a distance between shapes. We study a family of metrics on the space of curves, which includes several recently proposed metrics, for which the metrics ...

Elsevier2014

Quasiconformal Embeddings of Y-Pieces

Robert Silhol

In this paper we construct quasiconformal embeddings from Y-pieces that contain a short boundary geodesic into degenerate ones. These results are used in a companion paper to study the Jacobian tori of Riemann surfaces that contain small simple closed geod ...

Springer Heidelberg2014

Overview of the Geometries of Shape Spaces and Diffeomorphism Groups

Martins Bruveris, Martin Bauer

This article provides an overview of various notions of shape spaces, including the space of parametrized and unparametrized curves, the space of immersions, the diffeomorphism group and the space of Riemannian metrics. We discuss the Riemannian metrics th ...

Springer Verlag2014

Geodesic distance for right invariant Sobolev metrics of fractional order on the diffeomorphism group

Martins Bruveris, Martin Bauer

We study Sobolev-type metrics of fractional order s a parts per thousand yen 0 on the group Diff (c) (M) of compactly supported diffeomorphisms of a manifold M. We show that for the important special case M = S (1), the geodesic distance on Diff (c) (S (1) ...

Springer Verlag2013

Computational Approach to the Geometry of Compact Riemann Surfaces

Manuel Racle

The goal of this document is to provide a generalmethod for the computational approach to the topology and geometry of compact Riemann surfaces. The approach is inspired by the paradigms of object oriented programming. Our methods allow us in particular to ...

EPFL2013

Concrete shells – Towards efficient structures: Construction of an ellipsoidal concrete shell in Switzerland

Aurelio Muttoni, Miguel Fernández Ruiz

Concrete shells have been widely used in the past as economical and suitable solutions for a number of structures such as roofs, silos, cooling towers or offshore platforms. Taking advantage of their single or double curvature, bending moments and shear fo ...

Structural Concrete2013

Geodesic distance for right invariant Sobolev metrics of fractional order on the diffeomorphism group. II

Martins Bruveris, Martin Bauer

The geodesic distance vanishes on the group of compactly supported diffeomorphisms of a Riemannian manifold of bounded geometry, for the right invariant weak Riemannian metric which is induced by the Sobolev metric of order on the Lie algebra of vector fie ...

Springer Verlag2013

Covering Cubes and the Closest Vector Problem

Friedrich Eisenbrand, Martin Niemeier, Nicolai Hähnle

We provide the currently fastest randomized (1+epsilon)-approximation algorithm for the closest vector problem in the infinity-norm. The running time of our method depends on the dimension n and the approximation guarantee epsilon by 2^(O(n))(log(1/epsilon ...

Acm Order Department, P O Box 64145, Baltimore, Md 21264 Usa2011

Derivatives with respect to metrics and applications: subgradient marching algorithm

This paper introduces a subgradient descent algorithm to compute a Riemannian metric that minimizes an energy involving geodesic distances. The heart of the method is the Subgradient Marching Algorithm to compute the derivative of the geodesic distance wit ...

Springer2010