Publications related to Ellipse

‘Ecological concerns weren’t the main reason why I took the bus, that association only came afterwards’: on shifts in meanings of everyday mobility

Reducing the modal share of car travel in commuting implies challenging meanings of everyday mobility that tie commuting to driving. Existing research has focussed on describing ways in which everyday mobility is meaningful. However, why shifts in meanings ...

2021

ON WAVEFRONT ABERRATIONS IN ASYMMETRIC AND MULTIPLE APERTURE OPTICAL SYSTEMS

Alessandro Grosso

The present work deals with monochromatic wavefront aberrations in optical systems without symmetries. The treatment begins with a class of systems characterized by misaligned spherical surfaces whose behavior is analyzed using the wavefront aberration exp ...

EPFL2021

Turbulence in the scrape-off layer of double-null tokamak configurations

Carrie Fiona Beadle

Understanding the turbulent dynamics in the outermost region of the tokamak is essential to predict and control the heat and particle loads to the vessel wall, a crucial problem for the entire fusion program. In this thesis, the problem is approached via t ...

EPFL2021

Eigendecomposition-Free Training of Deep Networks for Linear Least-Square Problems

Pascal Fua, Mathieu Salzmann, Zheng Dang, Kwang Moo Yi, Fei Wang, Yinlin Hu

Many classical Computer Vision problems, such as essential matrix computation and pose estimation from 3D to 2D correspondences, can be tackled by solving a linear least-square problem, which can be done by finding the eigenvector corresponding to the smal ...

IEEE COMPUTER SOC2021

3D Smith chart constant quality factor semi-circles contours for positive and negative resistance circuits

Mihai Adrian Ionescu, Andrei Müller

The article firstly proves that the constant quality factor (Q) contours for passive circuits, while represented on a 2D Smith chart, form circle arcs on a coaxal circle family. Furthermore, these circle arcs represent semi-circles families in the north he ...

2020

Full field dependence of primary aberrations in perturbed double-plane symmetric systems with a circular pupil

Toralf Scharf, Alessandro Grosso

This paper deals with the theory of primary aberrations for perturbed double-plane symmetric optical systems consisting of a combination of tilted and decentered surfaces and a circular pupil. First, the analytical expressions describing the full field beh ...

OPTICAL SOC AMER2020

Cloaking property of a plasmonic structure in doubly complementary media and three-sphere inequalities with partial data

Hoài-Minh Nguyên

We investigate cloaking property of negative-index metamaterials in the time-harmonic electromagnetic setting for the so-called doubly complementary media. These are media consisting of negative-index metamaterials in a shell (plasmonic structure) and posi ...

2020

A critically degenerate elliptic Dirichlet problem, spectral theory and bifurcation

Charles Stuart

In an open, bounded subset Omega of R-N such that 0 is an element of Omega we consider the nonlinear eigenvalue problem -Sigma(N)(i,j,=1) partial derivative(i){A(ij)(x)partial derivative(j)u} + V(x)u + n(x,del u)+ g(x, u) = lambda u in Omega integral(Omega ...

2020

X-Ray Nanotomography of Individual Pulp Fibre Bonds Reveals the Effect of Wall Thickness on Contact Area

Fibre bonds play an essential role in various properties of paper. Much research has focused on their strength, but the determination of the actual contact area also provides a challenge. Many of the research methods rely on optical tools, which are restri ...

Nature Research2019

Light refocusing with up-scalable resonant waveguide gratings in confocal prolate spheroid arrangements

Olivier Martin, Benjamin Gallinet, Zdenek Benes, Giorgio Quaranta, Guillaume Basset

Resonant waveguide gratings (RWGs) are thin-film structures, where coupled modesinterfere with the diffracted incoming wave and produce strong angular and spectral filtering. The combination of two finite-length and impedance matched RWGs allows the creati ...

2018

Stepwise Luneburg Lens for Bloch Surface Waves

Myun Sik Kim, Babak Vosoughi Lahijani

In order to enlarge the capability for in-plane manipulation of the Bloch surface wave (BSW), we investigate 2D gradient index (GRIN) optical components using a finite-difference time-domain (FDTD) numerical method. To ease difficulties in fabrication to a ...

2018

Carbon Nanotube Array Based Binary Gabor Zone Plate Lenses

Sunan Deng, Chaohui Li

Diffractive zone plates have a wide range of applications from focusing x-ray to extreme UV radiation. The Gabor zone plate, which suppresses the higher-order foci to a pair of conjugate foci, is an attractive alternative to the conventional Fresnel zone p ...

Nature Research2017

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

Core-shell InGaN/GaN nanowire light emitting diodes analyzed by electron beam induced current microscopy and cathodoluminescence mapping

Hua Zhang, Gwénolé Jean Jacopin

We report on the electron beam induced current (EBIC) microscopy and cathodoluminescence (CL) characterization correlated with compositional analysis of light emitting diodes based on core/shell InGaN/GaN nanowire arrays. The EBIC mapping of cleaved fully ...

Royal Soc Chemistry2015

Application aux équations aux dérivées partielles d'une méthode par point fixe et le problème des deux puits

Sébastien Basterrechea

This thesis consists of two parts. The first part is about a variant of Banach's fixed point theorem and its applications to several partial differential equations (PDE's), abstractly of the form [ \mathcal Lu + \mathcal Q(u) = f.] The main result of thi ...

EPFL2015

A microfluidic device to sort capsules by deformability: A numerical study

Lailai Zhu, Cecilia Rorai

Guided by extensive numerical simulations, we propose a microfluidic device that can sort elastic capsules by their deformability. The device consists of a duct embedded with a semi-cylindrical obstacle, and a diffuser which further enhances the sorting ca ...

Royal Society of Chemistry2014

Closed-circuit domain quadruplets in BaTiO3 nanorods embedded in a SrTiO3 film

Nava Setter

Cylindrical BaTiO3 nanorods embedded in < 100 >-oriented SrTiO3 epitaxial film in a brushlike configuration are investigated in the framework of the Ginzburg-Landau-Devonshire model. It is shown that strain compatibility at BaTiO3/SrTiO3 interfaces keeps B ...

Amer Physical Soc2014

Inexact accurate partitioned algorithms for fluid-structure interaction problems with finite elasticity in haemodynamics

Fabio Nobile, Christian Vergara

In this paper we consider the numerical solution of the three-dimensional fluid–structure interaction problem in haemodynamics, in the case of real geometries, physiological data and finite elasticity vessel deformations. We study some new inexact schemes, ...

Elsevier2014

Analysis of Image Registration with Tangent Distance

Pascal Frossard, Elif Vural

The computation of the geometric transformation between a reference and a target image, known as image registration or alignment, corresponds to the projection of the target image onto the transformation manifold of the reference image (the set of images g ...

2014

An Algorithm to Improve Parameterizations of Rational Bézier Surfaces Using Rational Bilinear Reparameterization

Bailin Deng, Wei Zeng

The parameterization of rational Bézier surfaces greatly affects rendering and tessellation results. The uniformity and orthogonality of iso-parametric curves are two key properties of the optimal parameterization. The only rational Bézier surfaces with un ...

2013