Publications associées à Pendule (horloge)

Reduced order models for coupled systems

Efficient numerical simulations of coupled multi-component systems can be particularly challenging. This is mostly due to the complexity of their solutions, as mutual interactions may cause emergent behaviors, including synchronization and instabilities. V ...

EPFL2023

Rocker oscillator time bases

Simon Nessim Henein, Ilan Vardi

Since the invention of the pendulum clock by Christiaan Huygens in 1657, precision timekeepers have been regulated by oscillators. Although the pendulum is not an isochronous oscillator, its introduction as a time basis for clock regulation led to a signif ...

2021

Shaking force balancing of a 2-DOF isotropic horological oscillator

Simon Nessim Henein, Hubert Pierre-Marie Benoît Schneegans, Etienne Frédéric Gabriel Thalmann

Despite centuries of research and significant advances, the escapement mechanism used to count and maintain oscillations of mechanical time bases remains a complex mechanism and a major source of energy losses. We showed in previous work that, instead of t ...

2021

OASE 108. Ups & Downs. Reception Histories in Architecture

Christophe van Gerrewey

What is good, less good, or bad architecture? This issue of OASE examines how shifting appreciations, for very diverse reasons, can function as a productive misunderstanding, and as a lever to advance architectural criticism and pry thinking about architec ...

nai0102021

Optical measurement method for mechanical time base characterization

Simon Nessim Henein, Etienne Frédéric Gabriel Thalmann

The recent adoption of silicon components by the mechanical watch industry has triggered the search for new time bases to advantageously replace the traditional balance and hairspring oscillator. In particular, flexure-based oscillators manufactured in sil ...

euspen2021

Flexure Pivot Oscillators for Mechanical Watches

Etienne Frédéric Gabriel Thalmann

It appears that the concerted efforts of the watchmaking industry are leading towards a limit in mechanical watch accuracy. The general consensus in horology is that the time base's quality factor, a dimensionless number that characterizes the oscillator d ...

EPFL2020

Tribological Approach to the Watch Movements

Valentine Agnès Madeleine Magnin

Mechanical watches are complex and sensitive systems that have to maintain a faultless precision over their lifetime. However, this precision can be altered by disturbances occurring during the functioning time, such as friction, lubricant drying, or wear, ...

EPFL2020

On Time Synchronization Issues in Time-Sensitive Networks with Regulators and Nonideal Clocks

Jean-Yves Le Boudec, Ludovic Bernard Gérard Thomas

Flow reshaping is used in time-sensitive networks (as in the context of IEEE TSN and IETF Detnet) in order to reduce burstiness inside the network and to support the computation of guaranteed latency bounds. This is performed using per-flow regulators (suc ...

Association for Computing Machinery2020

Automatically Starting and Secured Detent Escapement for a Timepiece

Simon Nessim Henein, Ilan Vardi

A horological detent escapement for a horological movement arranged to transmit a torque from said horological movement to an oscillating regulating organ of said horological movement, the regulating organ comprising a first mobile body and the escapement ...

2019

Fabrication and Characterisation of Epitaxial PMN-PT Nano-structures

Xiao Di

Downscaling of the minimal feature size, or the gate length has been the key for the exponential im-provement of the performance of the logic CMOS integrated circuits over the last six decades. How-ever, since about 2003, some fundamental limits in the dev ...

EPFL2019

Feasibility of Time Synchronization Attacks against PMU-based State-Estimation

Jean-Yves Le Boudec, Mario Paolone, Sergio Barreto Andrade, Marguerite Marie Nathalie Delcourt, Gyorgy Miklos Dan

The emerging measurement technology of phasor measurement units (PMUs) makes it possible to estimate the state of electrical grids in real-time, thus opening the way to new protection and control applications. PMUs rely on precise time synchronization, the ...

2019

Horological oscillator

Simon Nessim Henein, Ilan Vardi, Etienne Frédéric Gabriel Thalmann, Mohammad Hussein Kahrobaiyan, Billy Nussbaumer

Horological oscillator comprising: - a first inertial body (141; 151; 1305; 1405; 1505; 301; 311; 314; 41; 51; 507; 529; 544; 541; 901; 903) arranged to rotate with respect to a first axis; - a second inertial body (143; 153; 1306; 1406; 1506; 302; 313; 31 ...

2019

Theory and design of spherical oscillator mechanisms

Simon Nessim Henein, Roland Andreas Bitterli, Ilan Vardi, Lennart Rubbert, Mohammad Hussein Kahrobaiyan, Nicolas Ferrier, Billy Nussbaumer

In previous work, we showed that two degree of freedom oscillators can be advantageously applied to horological time bases since they can be used to eliminate the escapement mechanism. We subsequently examined planar two degree of freedom oscillators based ...

2018

Gravity-Insensitive Flexure Pivot Oscillators

Simon Nessim Henein, Ilan Vardi, Etienne Frédéric Gabriel Thalmann, Lennart Rubbert, Mohammad Hussein Kahrobaiyan

Classical mechanical watch plain bearing pivots have frictional losses limiting the quality factor of the hairspring-balance wheel oscillator. Replacement by flexure pivots leads to a drastic reduction in friction and an order of magnitude increase in qual ...

2018

Programmable Multistable Mechanisms: Design, modeling, characterization and applications

Mohamed Gamal Abdelrahman Ahmed Zanaty

Multistable Mechanisms are mechanical devices having more than one stable state. Since these mechanisms can maintain different deformations with zero force, they are advantageous for low power environments such as wristwatches and medical devices. In this ...

EPFL2018

The viscous torsional pendulum

François Gallaire, Francesco Viola

A disk that is free to rotate about its axis and connected to a torsional spring behaves as a damped oscillator when twisted and released. The initial elastic energy is periodically turned to kinetic energy and it gets progressively dissipated by the visco ...

Academic Press Ltd- Elsevier Science Ltd2017

Cyber-attack on Packet-Based Time Synchronization Protocols: the Undetectable Delay Box

Jean-Yves Le Boudec, Aswin Suresh, Sergio Barreto Andrade

We present a cyber-attack on packet-based time synchronization protocols (PBTSP) with high-accuracy requirements. The cyber-attack is undetectable from the PBTSP's perspective and exploits a vulnerability that is in the nature of all PBTSPs. It can be succ ...

Ieee2016

Quantum limits on measurement and control of a mechanical oscillator

Vivishek Sudhir

The precision measurement of position has a long-standing tradition in physics. Cavendish's verification of the universal law of gravitation using a torsion pendulum, Perrin's confirmation of the atomic hypothesis via the precise measurement of the Brownia ...

EPFL2016

The motion of a 2D pendulum in a channel subjected to an incoming flow

François Gallaire, Andrea Fani

The flow around a tethered cylinder subjected to an incoming flow transverse to its main axis and confined in a channel is investigated by means of global stability analysis of the full coupled body-fluid problem. When the cylinder is strongly confined (ra ...

Cambridge University Press2015

Exploiting Dynamic Timing Margins in Microprocessors for Frequency-Over-Scaling with Instruction-Based Clock Adjustment

Andreas Peter Burg, Georgios Karakonstantis, Jeremy Hugues-Felix Constantin, Anupam Chattopadhyay

Static timing analysis provides the basis for setting the clock period of a microprocessor core, based on its worst-case critical path. However, depending on the design, this critical path is not always excited and therefore dynamic timing margins exist th ...

2015