Publications associées à Network Time Protocol

Improved Network-Calculus Nodal Delay-Bounds in Time-Sensitive Networks

Jean-Yves Le Boudec, Eleni Stai, Ehsan Mohammadpour

In time-sensitive networks, bounds on worst-case delays are typically obtained by using network calculus and assuming that flows are constrained by bit-level arrival curves. However, in IEEE TSN or IETF DetNet, source flows are constrained on the number of ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2023

Worst-Case Delay Analysis of Time-Sensitive Networks with Network Calculus

Seyed Mohammadhossein Tabatabaee

Time-sensitive networks, as in the context of IEEE Time-Sensitive Networking (TSN) and IETF Deterministic Networking (DetNet), offer deterministic services with guaranteed bounded latency in order to support safety-critical applications. In this thesis, we ...

EPFL2023

Efficient and Accurate Handling of Periodic Flows in Time-Sensitive Networks

Jean-Yves Le Boudec, Seyed Mohammadhossein Tabatabaee

Total Flow Analysis (TFA) is a method for the worst-case analysis of time-sensitive networks. It uses service curve characterizations of the network nodes and arrival curves of flows at their sources; for tractability, the latter are often taken to be line ...

2023

Control upgrade for the TCV coils power supplies

Damien Fasel, Ugo Siravo, Jérémie Dubray, Nicolas Cherix

The Tokamak a` Configuration Variable (TCV) coil converters are fed, during the plasma pulse, by a flywheel generator (FG) providing the AC voltages few seconds before the plasma pulse. The synchronization with the 120 Hz frequency delivered by the FG, var ...

ELSEVIER SCIENCE SA2023

A Network Calculus Analysis of Asynchronous Mechanisms in Time-Sensitive Networks

Ehsan Mohammadpour

Time-sensitive networks provide worst-case guarantees for applications in domains such as the automobile, automation, avionics, and the space industries. A violation of these guarantees can cause considerable financial loss and serious damage to human live ...

EPFL2023

Analysis of Dampers in Time-Sensitive Networks With Non-Ideal Clocks

Jean-Yves Le Boudec, Ehsan Mohammadpour

Dampers are devices that reduce delay jitter in the context of time-sensitive networks, by delaying packets for the amount written in packet headers. Jitter reduction is required by some real-time applications; beyond this, dampers have the potential to so ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2022

Security Measures for Grids Against Rank-1 Undetectable Time-Synchronization Attacks

Jean-Yves Le Boudec, Marguerite Marie Nathalie Delcourt

Time-synchronization attacks on phasor measurement units (PMUs) pose a real threat to smart grids; it was shown that they are feasible in practice and that they can have a nonnegligible negative impact on state estimation, without triggering the bad data d ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2022

Time-Synchronization Attack Detection in Unbalanced Three-Phase Systems

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

Phasor measurement units (PMU) rely on an accurate time-synchronization to phase-align the phasors and timestamp the voltage and current phasor measurements. Among the symmetrical components computed from the phasors in three-phase systems, the standard pr ...

2021

TDOA Source-Localization Technique Robust to Time-Synchronization Attacks

Jean-Yves Le Boudec, Marguerite Marie Nathalie Delcourt

In this paper, we focus on the localization of a passive source from time difference of arrival (TDOA) measurements. TDOA values are computed with respect to pairs of fixed sensors that are required to be accurately time-synchronized. This constitutes a we ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2021

Time-Synchronization Attacks against Critical Infrastructures and their Mitigation

Marguerite Marie Nathalie Delcourt

This work focuses on the security of critical infrastructures against time-synchronization attacks (TSA). A TSA can impact any network that relies on the dynamic analysis of data, by altering the time synchronization between its nodes. Such attacked networ ...

EPFL2021

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

Estimating network travel time reliability with network partitioning

Nikolaos Geroliminis, Mohammadreza Saeedmanesh

Network travel time reliability can be represented by a relationship between network space-mean travel time and the standard deviation of network travel time. The primary objective of this paper is to improve estimation of the network travel time reliabili ...

PERGAMON-ELSEVIER SCIENCE LTD2020

Two-Step Synthesis of Linear and Bent Dicarboxylic Acid Metalloligands with Lengths of up to 3 nm

Rosario Scopelliti, Kay Severin, Farzaneh Fadaei Tirani, Suzanne Maria Jansze, Ophélie Marie Planes

Nanometer-sized polycarboxylate ligands are interesting building blocks for metallasupramolecular chemistry, but access to these compounds is often limited by complicated synthetic pathways. Here, we describe a simple two-step protocol, which allows prepar ...

2020

Easily Deployable Underwater Acoustic Navigation System for Multi-Vehicle Environmental Sampling Applications

Alcherio Martinoli, Alexander Bahr, Felix Stephan Schill, Anwar Ahmad Quraishi

Water as a medium poses a number of challenges for robots, limiting the progress of research in underwater robotics vis-a-vis ground or aerial robotics. The primary challenges are satellite based positioning and radio communication being unusable due to hi ...

IEEE2019

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

Activity induced synchronization: Mutual flocking and chiral self-sorting

Ignacio Pagonabarraga Mora

Synchronization, the temporal coordination of coupled oscillators, allows fireflies to flash in unison, neurons to fire collectively, and human crowds to fall in step on the London millenium bridge. Here, we interpret active (or self-propelled) chiral micr ...

2019

On Cyclic Dependencies and Regulators in Time-Sensitive Networks

Jean-Yves Le Boudec, Ludovic Bernard Gérard Thomas

For time-sensitive networks, as in the context of IEEE TSN and IETF Detnet, cyclic dependencies are associated with certain fundamental properties such as improving availability and decreasing reconfiguration effort. Nevertheless, the existence of cyclic d ...

IEEE2020

Improved Credit Bounds for the Credit-Based Shaper in Time-Sensitive Networking

Jean-Yves Le Boudec, Eleni Stai, Ehsan Mohammadpour

In Time-Sensitive Networking (TSN), it is important to formally prove per-flow latency and backlog bounds. To this end, recent works have applied network calculus and obtained latency bounds from service curves. The latency component of such service curves ...

2019

Impact of Time Dissemination Technologies on Synchrophasor Estimation Accuracy

Mario Paolone, Guglielmo Frigo, Asja Derviskadic

The paper discusses the influence of the time synchronization technique on the synchrophasor estimation accuracy in modern Phasor Measurement Units (PMU). Specifically, we make reference to Global Positioning System (GPS), Precision Time Protocol (PTP) and ...

2019

A Sensor Network Architecture for Digital SiPM-Based PET Systems

Edoardo Charbon, Claudio Bruschini, Francesco Gramuglia

Digital silicon photo-multipliers (SiPMs) have emerged in the recent past as a viable low cost alternative to photomultiplier tubes in positron emission tomography systems, providing multiple timestamps, energy and scintillation coordinates at high spatial ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2018