Publications associées à Marginal stability

Critical degeneracy in a nonlinear hyperbolic equation can produce atypical instability

This paper deals with the initial value problem for a semilinear wave equation on a bounded domain and solutions are required to vanish on the boundary of this domain. The essential feature of the situation considered here is that the ellipticity of the sp ...

2024

A Provably Stable Iterative Learning Controller for Continuum Soft Robots

Josephine Anna Eleanor Hughes, Francesco Stella

Fully exploiting soft robots' capabilities requires devising strategies that can accurately control their movements with the limited amount of control sources available. This task is challenging for reasons including the hard-to-model dynamics, the system' ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2023

Long Time Behavior of an Age- and Leaky Memory-Structured Neuronal Population Equation

Valentin Marc Schmutz

We study the asymptotic stability of a two-dimensional mean-field equation, which takes the form of a nonlocal transport equation and generalizes the time-elapsed neuron network model by the inclusion of a leaky memory variable. This additional variable ca ...

2022

A Note on BIBO Stability

Michaël Unser

The statements on the BIBO stability of continuoustime convolution systems found in engineering textbooks are often either too vague (because of lack of hypotheses) or mathematically incorrect. What is more troubling is that they usually exclude the identi ...

2020

Avoidance of Convex and Concave Obstacles with Convergence ensured through Contraction

Aude Billard, Lukas Huber

This paper presents a closed-form approach to obstacle avoidance for multiple moving convex and star-shaped concave obstacles. The method takes inspiration in harmonic-potential fields. It inherits the convergence properties of harmonic potentials. We prov ...

2019

Stability Analysis of Primary Plug-and-Play and Secondary Leader-Based Controllers for DC Microgrid Clusters

Giancarlo Ferrari Trecate, Michele Tucci, Andrea Martinelli, Renke Han

In this paper, we propose a new hierarchical control scheme for microgrid (MG) clusters, given by the interconnection of atomic dc MGs with ZIP loads, each composed by both grid-forming and grid-feeding converters. In the primary level, we develop a new Pl ...

IEEE Institute of Electrical and Electronics Engineers2019

Adaptive model predictive control for linear time varying MIMO systems

Vojislav Gligorovski

A robust, adaptive Model Predictive Control (MPC) approach for asymptotically stable, constrained linear time-varying (LTV) systems with multiple inputs and outputs is proposed. The approach consists of two-steps, carried out on-line with a receding horizo ...

2019

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

Three-dimensional Rayleigh–Taylor instability under a unidirectional curved substrate

François Gallaire, Gioele Mariano Nicolò Balestra, Pierre-Thomas Paul Brun, Nicolas Igor Jacques Kofman

We investigate the Rayleigh–Taylor instability of a thin liquid film coated on the inside of a cylinder whose axis is orthogonal to gravity. We are interested in the effects of geometry on the instability, and contrast our results with the classical case o ...

Cambridge University Press2017

Constrained Spectrum Control

Colin Neil Jones, Melanie Nicole Zeilinger, Jean-Hubert Hours

A novel Nonlinear Model Predictive Control (NMPC) scheme is proposed in order to shape the harmonic response of constrained nonlinear systems. The salient ingredient is the short-time Fourier transform (STFT) of the system's output signal, which is constra ...

Institute of Electrical and Electronics Engineers2015

Soft Constrained Model Predictive Control With Robust Stability Guarantees

Colin Neil Jones, Melanie Nicole Zeilinger

Soft constrained model predictive control (MPC) is frequently applied in practice in order to ensure feasibility of the optimization during online operation. Standard techniques offer global feasibility by relaxing state or output constraints, but cannot e ...

Institute of Electrical and Electronics Engineers2014

Constant-yield control of continuous bioreactors

Georgios Savoglidis

The process of anaerobic digestion is a common application in the treatment of industrial and communal wastewater treatment plants. The biochemical reactions taking place inside the fermenter can be described by a system of first order differential equatio ...

Elsevier Science Sa2013

Multistability of twisted states in non-locally coupled Kuramoto-type models

Martin Hasler

A ring of N identical phase oscillators with interactions between L-nearest neighbors is considered, where L ranges from 1 (local coupling) to N/2 (global coupling). The coupling function is a simple sinusoid, as in the Kuramoto model, but with a minus sig ...

American Institute of Physics2012

Mesoscale and clusters of synchrony in networks of bursting neurons

Martin Hasler, Igor Belykh

We study the role of network architecture in the formation of synchronous clusters in synaptically coupled networks of bursting neurons. We give a simple combinatorial algorithm that finds the largest synchronous clusters from the network topology. We demo ...

American Institute of Physics2011

Robust stability properties of soft constrained MPC

Colin Neil Jones, Melanie Nicole Zeilinger

In Model Predictive Control, the enforcement of hard state constraints can be overly conservative or even infeasible, especially in the presence of disturbances. This work presents a soft constrained MPC approach that provides closed- loop stability even f ...

IEEE2010

The radial wave operator in similarity coordinates

Roland Donninger

We present a rigorous functional analytic setting to study the radial wave equation in similarity coordinates. As an application we analyze linear stability of the fundamental self-similar solution of the wave equation with a focusing power nonlinearity. T ...

American Institute of Physics2010

BM: An Iterative Method to Learn Stable Non-Linear Dynamical Systems with Gaussian Mixture Models

Aude Billard, Seyed Mohammad Khansari Zadeh

We model the dynamics of non-linear discrete (i.e. point-to- point) robot motions as a time-independent system described by an autonomous dynamical system (DS). We propose an iterative algorithm to estimate the form of the DS through a mixture of Gaussian ...

2010

A Numerical Sufficiency Test for the Asymptotic Stability of Linear Time-Varying Systems

Dominique Bonvin, Philippe Müllhaupt, Davide Buccieri

A numerical sufficiency test for the asymptotic stability of linear time-varying Hurwitz systems is proposed. The algorithmic procedure constructs a bounding tube in which the state is guaranteed to stay. The continuous-time system is evaluated at discrete ...

2007

Chapter 5: Physics of energetic ions

Ambrogio Fasoli, Duccio Testa

This chapter reviews the progress accomplished since the redaction of the first ITER Physics Basis (1999 Nucl. Fusion 39 2137-664) in the field of energetic ion physics and its possible impact on burning plasma regimes. New schemes to create energetic ions ...

IOP Publishing Ltd2007

Stability properties of anisotropic pressure stellarator plasmas with fluid and noninteractive energetic particles

Wilfred Anthony Cooper, Jonathan Graves, Trach-Minh Tran

The three-dimensional (3-D) VMEC code has been modified to model an energetic species with a variant of a Bi-Maxwellian distribution function that satisfies the constraint B . del F-h = 0, and the 3-D TERPSICHORE stability code has been extended to investi ...

2006