Publications associées à Calotte sphérique

On the Maximum Power Density of Implanted Antennas within Simplified Body Phantoms

Anja Skrivervik, Mingxiang Gao, Zvonimir Sipus

With the application requirements of wireless technology in implantable bioelectronics, knowledge of the fundamental limits for implanted antennas becomes critical. In this work, we investigated the variation of maximum power density within simplified body ...

IEEE2022

Geometric Percolation of Spherically Symmetric Fractal Aggregates

Claudio Grimaldi

The connectedness percolation threshold (phi(c)) for spherically symmetric, randomly distributed fractal aggregates is investigated as a function of the fractal dimension (d(F)) of the aggregates through a mean-field approach. A pair of aggregates (each of ...

SPRINGER2022

Spherical cap harmonic analysis (SCHA) for characterising the morphology of rough surface patches

Katrin Beyer, Mahmoud S. M. Shaqfa

We use spherical cap harmonic (SCH) basis functions to analyse and reconstruct the morphology of scanned genus-0 rough surface patches with open edges. We first develop a novel one-to-one conformal mapping algorithm with minimal area distortion for paramet ...

2021

Two-dimensional modelling of transient capillary driven damped micro-oscillations and self-alignment of objects in microassembly

François Gallaire

In the fields of microgripping and microassembly, the self-alignment motion of a solid micro-object linked by a liquid meniscus to a substrate or a tool is an inexpensive way to overcome the current limitations of the assembly processes at microscale by ge ...

Cambridge University Press2021

Realizing doubles: a conjugation zoo

Jérôme Scherer

Conjugation spaces are topological spaces equipped with an involution such that their fixed points have the same mod 2 cohomology (as a graded vector space, a ring and even an unstable algebra) but with all degrees divided by two, generalizing the classica ...

CAMBRIDGE UNIV PRESS2021

Infinitesimal asphericity changes the universality of the jamming transition

Matthieu Wyart, Carolina Brito Carvalho dos Santos

The jamming transition of non-spherical particles is fundamentally different from the spherical case. Non-spherical particles are hypostatic at their jamming points, while isostaticity is ensured in the case of the jamming of spherical particles. This stru ...

IOP PUBLISHING LTD2020

Graph-based regularization of inverse problems in imaging

Mattia Rossi

As of today, the extension of the human visual capabilities to machines remains both a cornerstone and an open challenge in the attempt to develop intelligent systems. On the one hand, the development of more and more sophisticated imaging devices, capable ...

EPFL2020

A Weak Form Implementation of Nonlinear Axisymmetric Shell Equations With Examples

Pedro Miguel Nunes Pereira de Almeida Reis, Matteo Pezzulla

We present a weak form implementation of the nonlinear axisymmetric shell equations. This implementation is suitable to study the nonlinear deformations of axisymmetric shells, with the capability of considering a general mid-surface shape, non-homogeneous ...

2019

Radiation Limitations for Small Implanted Antennas

Anja Skrivervik, Zvonimir Sipus

Medical implants with communication capability are becoming increasingly popular with today’s trends to continuously monitor patient’s condition. This is a major challenge for antenna designers since the implants are inherently small and placed in a commun ...

IEEE2019

Fundamental Limits for Implanted Antennas: Maximum Power Density Reaching Free Space

Anja Skrivervik, Zvonimir Sipus

Medical implants with communication capability are becoming increasingly popular with today’s trends to continuously monitor patient’s condition. This is a major challenge for antenna designers since the implants are inherently small and placed in a commun ...

2019

Buckling of geometrically confined shells

Matteo Pezzulla

We study the periodic buckling patterns that emerge when elastic shells are subjected to geometric confinement. Residual swelling provides access to range of shapes (saddles, rolled sheets, cylinders, and spherical sections) which vary in their extrinsic a ...

ROYAL SOC CHEMISTRY2019

Geometry Aware Convolutional Filters for Omnidirectional Images Representation

Pascal Frossard, Renata Khasanova

Due to their wide field of view, omnidirectional cameras are frequently used by autonomous vehicles, drones and robots for navigation and other computer vision tasks. The images captured by such cameras, are often analyzed and classified with techniques de ...

2019

Specification of aspherical surfaces used as refractive elements in micro-optical systems

Toralf Scharf, Wilfried Noell, Jeremy Béguelin

The optical performance of refractive plano-convex microlenses is mainly related to the quality of their (a)spherical surface. An efficient tolerancing of this surface is a key step towards the manufacturing of high quality microlenses. However, we demonst ...

SPIE-INT SOC OPTICAL ENGINEERING2019

Graph-Based Detection of Seams In 360-Degree Images

Pascal Frossard, Francesca De Simone, Sohyeong Kim, Roberto Gerson De Albuquerque Azevedo

In this paper, we propose an algorithm to detect a specific kind of distortions, referred to as seams, which commonly occur when a 360-degree image is represented in planar domain by projecting the sphere to a polyhedron, e.g, via the Cube Map (CM) project ...

2019

Spherical Clustering of Users Navigating 360° Content

Pascal Frossard, Francesca De Simone, Laura Toni

In Virtual Reality (VR) applications, understanding how users explore the omnidirectional content is important to optimize content creation, to develop user-centric services, or even to detect disorders in medical applications. Clustering users based on th ...

IEEE2019

Improved calibration of vertical scanning optical profilometers for spherical profiles measurements

Toralf Scharf, Wilfried Noell, Jeremy Béguelin

A new method for calibrating optical scanning profilometers is presented. Especially adapted to spherical and aspherical profile measurements, it shows an increase of accuracy bigger than one order of magnitude for radius of curvature measurements. Calibra ...

2018

Rate Distortion Optimized Graph Partitioning for Omnidirectional Image Coding

Pascal Frossard, Francesca De Simone, Thomas Maugey, Mira Rizkallah

Omnidirectional images are spherical signals captured by cameras with 360-degree field of view. In order to be compressed using existing encoders, these signals are mapped to planar domain. A commonly used planar representation is the equirectangular one, ...

IEEE COMPUTER SOC2018

Rayleigh-Taylor instability under a spherical substrate

Gioele Mariano Nicolò Balestra, François Gallaire, David Minh-Phuc Nguyen

We investigate the Rayleigh-Taylor instability of a thin viscous film coating the inside of a spherical substrate. The aim of this work is to find and characterize the instability pattern in this spherical geometry. In contrast to the Rayleigh-Taylor insta ...

2018

Sampling and Exact Reconstruction of Pulses with Variable Width

Martin Vetterli, Adam James Scholefield, Loïc Arnaud Baboulaz, Gilles Baechler

Recent sampling results enable the reconstruction of signals composed of streams of fixed-shaped pulses. These results have found applications in topics as varied as channel estimation, biomedical imaging and radio astronomy. However, in many real signals, ...

Institute of Electrical and Electronics Engineers2017

Deformable block based motion estimation in omnidirectional image sequences

Pascal Frossard, Francesca De Simone

This paper presents an extension of block-based motion estimation for omnidirectional videos, based on a camera and translational object motion model that accounts for the spherical geometry of the imaging system. We use this model to design a new algorith ...

2017