Results 11 to 20 of about 19,539 (276)

Carleman estimates for the one-dimensional heat equation with a discontinuous coefficient and applications [PDF]

open access: yes, 2006
International audienceWe study the observability and some of its consequences for the one-dimensional heat equation with a discontinuous coefficient (piecewise $\Con^1$).
Benabdallah, Assia   +2 more
core   +3 more sources

Observability and uniqueness theorem for a coupled hyperbolic system

open access: yesInternational Journal of Mathematics and Mathematical Sciences, 2000
We deal with the inverse inequality for a coupled hyperbolic system with dissipation. The inverse inequality is an indispensable inequality that appears in the Hilbert Uniqueness Method (HUM), to establish equivalence of norms which guarantees uniqueness
Boris V. Kapitonov, Joel S. Souza
doaj   +1 more source

Geometric control condition for the wave equation with a time-dependent observation domain [PDF]

open access: yes, 2016
We characterize the observability property (and, by duality, the controllability and the stabilization) of the wave equation on a Riemannian manifold $\Omega,$ with or without boundary, where the observation (or control) domain is time-varying.
Lebeau, Gilles   +3 more
core   +4 more sources

Unique continuation estimates for the Kolmogorov equation in the whole space [PDF]

open access: yes, 2015
We prove in this Note an observation estimate at one point in time for the Kolmogorov equation in the whole space. Such estimate implies the observability and the null controllability for the Kolmogorov equation with a control region which is ...
Zhang, Yubiao
core   +3 more sources

Fault Location Observability using Phasor Measurements Units via Semidefinite Programming

open access: yesIEEE Access, 2016
This paper presents a placement algorithm for fault location observability using phasor measurement units (PMUs) in the presence or absence of zero injection buses.
Theodoros A. Alexopoulos   +2 more
doaj   +1 more source

Observed inequality in urban greenspace exposure in China

open access: yesEnvironment International, 2021
Given the important role of green environments playing in healthy cities, the inequality in urban greenspace exposure has aroused growing attentions. However, few comparative studies are available to quantify this phenomenon for cities with different population sizes across a country, especially for those in the developing world. Besides, commonly used
Yimeng Song   +13 more
openaire   +4 more sources

Sharp Observability Inequalities for Hyperbolic Systems with Potentials

open access: yesESAIM: Control, Optimisation and Calculus of Variations, 2023
This paper is devoted to a sharp internal/boundary observability inequality for a hyperbolic system with a zero order potential. For this purpose, we first establish a new Carleman estimate for hyperbolic operator inH1-norm. Based on this Carleman estimate and a modified auxiliary optimal control problem, we obtain Carleman estimate for hyperbolic ...
Fu, Xiaoyu, Liao, Zhonghua, Lü, Qi
openaire   +1 more source

Asymptotics for optimal design problems for the Schr\"odinger equation with a potential [PDF]

open access: yes, 2018
We study the problem of optimal observability and prove time asymptotic observability estimates for the Schr\"odinger equation with a potential in $L^{\infty}(\Omega)$, with $\Omega\subset \mathbb{R}^d$, using spectral theory. An elegant way to model the
Merkurjev, Ekaterina, Waters, Alden
core   +2 more sources

Null controllability for a coupled system of degenerate/singular parabolic equations in nondivergence form

open access: yesElectronic Journal of Qualitative Theory of Differential Equations, 2018
We deal with a control problem for a coupled system of two degenerate singular parabolic equations in non-divergence form with degeneracy and singularity appearing at an interior point of the space domain. In particular, we consider the well-posedness of
Jawad Salhi
doaj   +1 more source

Optimal Placement of Phasor Measurement Unit in Smart Grids Considering Multiple Constraints

open access: yesJournal of Modern Power Systems and Clean Energy, 2023
The distribution of measurement noise is usually assumed to be Gaussian in the optimal phasor measurement unit (PMU) placement (OPP) problem. However, this is not always accurate in practice.
Tengpeng Chen   +4 more
doaj   +1 more source

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