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BEGIN:VEVENT
SUMMARY:Jean-Michel Coron (Université Pierre et Marie Curie)
DTSTART:20200908T150000Z
DTEND:20200908T161500Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/1
DESCRIPTION:Title: Rapid and finite-time stabilization\nby Jean-Michel Coron (U
niversité Pierre et Marie Curie) as part of Control in Times of Crisis. O
nline seminar.\n\n\nAbstract\nWe present various results on the rapid and
the finite-time stabilization of control systems.\nThis includes control s
ystems in finite dimension (with an application to a quadcopter\nsliding o
n a plane) as well as control systems modeled by means of partial differen
tial equations (1-D linear hyperbolic systems\, 1-D linear parabolic equat
ions and KdV equations).\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Claudia Moreno (Université Paris-Saclay (UVSQ))
DTSTART:20200915T150000Z
DTEND:20200915T153000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/2
DESCRIPTION:Title: Control of a partial differential equation system of dispersive
type\nby Claudia Moreno (Université Paris-Saclay (UVSQ)) as part of C
ontrol in Times of Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Irene Marín-Gayte (Universidad de Sevilla)
DTSTART:20200915T153000Z
DTEND:20200915T160000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/3
DESCRIPTION:Title: Theoretical and numerical bi-objective optimal control: Nash equ
ilibria\nby Irene Marín-Gayte (Universidad de Sevilla) as part of Con
trol in Times of Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marius Tucsnak (Université de Bordeaux)
DTSTART:20200922T150000Z
DTEND:20200922T160000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/4
DESCRIPTION:Title: Does the boundary controlled heat equation define an exactly con
trollable system?\nby Marius Tucsnak (Université de Bordeaux) as part
of Control in Times of Crisis. Online seminar.\n\n\nAbstract\nIt is commo
nly accepted in the control theory of PDEs that parabolic equations\, due
to the smoothing effect\,\ndo not determine exactly controllable systems w
hen controlled from the boundary. The aim of this presentation\nis to expl
ain how the heat semigroup can be restricted to an appropriate function sp
ace on which\, when\ncontrolled from the boundary\, it could determine an
exactly controllable systems. To this aim\, we first recall\nsome abstract
concepts concerning reachability in an infinite dimensional context\, ins
isting on the general\nrelevance of the concept of reachable space. We nex
t describe some recent advances on the reachable space of\nthe boundary co
ntrolled heat equation in one space dimension. We next discuss the exact c
ontrollability of this\nsystem in appropriate spaces of analytic functions
. We give applications in determining the reachable space\nwith smooth inp
uts\, with possible application to nonlinear problems. Finally\, we discus
s the possible\nimplications of our methods to improve the existing estima
tes of the control constant in small time.\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jose A. Villa ((UNAM\, Mexico))
DTSTART:20200929T150000Z
DTEND:20200929T153000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/5
DESCRIPTION:Title: Hierarchical control for the semilinear heat equation.\nby J
ose A. Villa ((UNAM\, Mexico)) as part of Control in Times of Crisis. Onli
ne seminar.\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gilcenio Rodrigues ((U F di Piaui\, Brazil))
DTSTART:20200929T153000Z
DTEND:20200929T160000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/6
DESCRIPTION:Title: Boundary controllability of a one-dimensional phase-field system
with one control force\nby Gilcenio Rodrigues ((U F di Piaui\, Brazil
)) as part of Control in Times of Crisis. Online seminar.\n\nAbstract: TBA
\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Piermarco Cannarsa (Università degli Studi di Roma "Tor Vergata")
DTSTART:20201006T150000Z
DTEND:20201006T160000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/7
DESCRIPTION:Title: Bilinear control for evolution equations\nby Piermarco Canna
rsa (Università degli Studi di Roma "Tor Vergata") as part of Control in
Times of Crisis. Online seminar.\n\n\nAbstract\nThe observability for the
classical Schrödinger equation usually holds for very short\ntime\, under
suitable geometric conditions. However\, it is not the case when the unde
rlying geometry\nis sub-elliptic. In this talk we consider the Schrodinger
equation associated with the Bouendi-\nGrushin operator. The Bouendi-Grus
hin operator is a subelliptic operator which is degenerate\nalong a line.
In the Bouendi case\, the associated Schrödinger equation exhibits a tran
sport effect\nwhich leads to a "sub-elliptic" geometric control condition
and a minimal time to ensure the\nobservability. For general Bouendi-Grush
in with stronger sub-elliptic effect\, the observability for\nthe Schrödi
nger equation is never true. These observability results can be seen from
a semi-\nclassical point of view\, through a optimal resolvent esti- mate.
Consequently\, our resolvent\nestimate leads to an energy decay rate for
the associated damped wave equation. This talk is\nbased on a joint work w
ith Nicolas Burq and another with Cyril Letrouit.\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Chenmin Sun (U. Cergy)
DTSTART:20201013T153000Z
DTEND:20201013T160000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/8
DESCRIPTION:Title: Classical and semi-classical observability for the Bouendi-Grush
in operator\nby Chenmin Sun (U. Cergy) as part of Control in Times of
Crisis. Online seminar.\n\n\nAbstract\nThe observability for the classical
Schrödinger equation usually holds for very short\ntime\, under suitable
geometric conditions. However\, it is not the case when the underlying ge
ometry\nis sub-elliptic. In this talk we consider the Schrodinger equation
associated with the Bouendi-\nGrushin operator. The Bouendi-Grushin opera
tor is a subelliptic operator which is degenerate\nalong a line. In the Bo
uendi case\, the associated Schrödinger equation exhibits a transport eff
ect\nwhich leads to a "sub-elliptic" geometric control condition and a min
imal time to ensure the\nobservability. For general Bouendi-Grushin with s
tronger sub-elliptic effect\, the observability for\nthe Schrödinger equa
tion is never true. These observability results can be seen from a semi-\n
classical point of view\, through a optimal resolvent esti- mate. Conseque
ntly\, our resolvent\nestimate leads to an energy decay rate for the assoc
iated damped wave equation. This talk is\nbased on a joint work with Nicol
as Burq and another with Cyril Letrouit.\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Amaury Hayat (Ecole des Ponts Paristech)
DTSTART:20201013T150000Z
DTEND:20201013T153000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/9
DESCRIPTION:Title: Stabilization of some nonlinear hyperbolic PDEs\nby Amaury H
ayat (Ecole des Ponts Paristech) as part of Control in Times of Crisis. On
line seminar.\n\n\nAbstract\nAbstract: We consider two types of systems :
density-velocity systems and traffic flows.\nDensity-velocity systems enco
mpass many physical equations: isentropic Euler equations\,\nSaint-Venant
equations\, osmosis model\, etc. We show that these equations have a local
\ndissipative property that allows to stabilize any steady-state with boun
dary feedback\ncontrols\, provided some physical assumption. Moreover\, th
is holds even if we have no\nknowledge of some the system parameters or wi
th a single control.\nTraffic flows are very interesting from a control pe
rspective. In many situations the\nsteady-states are unstable\, leading to
travelling waves\, known as stop-and-go waves by\nengineers or simply jam
. From a mathematical point of view they can be represented by\ncoupled hy
perbolic PDEs with solutions of class BV. We will present on-going work sh
owing\nhow one can try to stabilize the steady-states using autonomous veh
icles\, i.e. pointwise\ncontrols. This leads to a system of ODEs and PDEs
coupled by a flux relation\, which provoke\nnon-classical shocks. The solu
tions are then at most BV and the control is contained in the\ndynamics of
the ODEs.\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/9/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Karl Kunisch (U Grass\, Austria)
DTSTART:20201020T150000Z
DTEND:20201020T161500Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/10
DESCRIPTION:Title: Solution Concepts for Optimal Feedback Control of Nonlinear Par
tial Differential Equations\nby Karl Kunisch (U Grass\, Austria) as pa
rt of Control in Times of Crisis. Online seminar.\n\n\nAbstract\nFeedback
control of nonlinear systems in practice is still frequently based on line
arisation\nand subsequent treatment by efficient Riccati solvers. Here we
want to follow different directions.\n\nI concentrate on three solution st
rategies which aim at the nonlinear control system directly. The\nfirst on
e is based on higher order Taylor expansions of the value function and lea
ds to controls\nwhich rely on generalized Ljapunov equations.\n\nThe secon
d approach is based on Newton steps applied to the HJB equation. Combined
with spectral\ntechniques and tensor calculus this allows to solve HJB equ
ations up to dimension 100. The results\nare demonstrated for the control
of discretized Fokker Planck equations.\n\nThe third technique circumvents
the direct solution of the HJB equation. Rather a neural network\nis trai
ned by means of a succinctly chosen ansatz and it is proven that it approx
imates the solution\nto the HJB equation as the dimension of the network i
s increased.\n\nThis work relies on collaborations with T.Breiten\, S.Dolg
ov\, D.Kalise\, L.Pfeiffer\, and D.Walter.\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Belhassen Dehman (Fac. des Sciences de Tunis\, Tunisia)
DTSTART:20201103T160000Z
DTEND:20201103T171500Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/11
DESCRIPTION:Title: Controllability of the Wave Equation on a rough compact manifol
d.\nby Belhassen Dehman (Fac. des Sciences de Tunis\, Tunisia) as part
of Control in Times of Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Suzanne Lenhart (University of Tennessee\, USA)
DTSTART:20201117T160000Z
DTEND:20201117T171500Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/12
DESCRIPTION:Title: Optimal control for management of aquatic population models
\nby Suzanne Lenhart (University of Tennessee\, USA) as part of Control in
Times of Crisis. Online seminar.\n\n\nAbstract\nOptimal control technique
s of ordinary and partial differential equations will be introduced\nto co
nsider management strategies for two different aquatic populations. In the
first example\,\nmanaging invasive species in rivers can be assisted by a
djustment of flow rates. Control of a flow\nrate in a partial differential
equation model for a population in a river will be used to keep the\npopu
lation from moving upstream. The second example represents a food chain on
the Turkish coast of\nthe Black Sea. Using data from the anchovy landings
in Turkey\, optimal control of the harvesting\nrate of the anchovy popula
tion in a system of three ordinary differential equations (anchovy\,\njell
yfish and zooplankton) will give management strategies.\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/12/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yuri Thamsten (Universidade Fluminense)
DTSTART:20201027T160000Z
DTEND:20201027T163000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/13
DESCRIPTION:Title: Local null controllability of a class of non-Newtonian incompre
ssible viscous fluids\nby Yuri Thamsten (Universidade Fluminense) as p
art of Control in Times of Crisis. Online seminar.\n\n\nAbstract\nWe inves
tigate the null controllability property of systems that\nmathematically d
escribe the dynamics of some non-Newtonian incompressible\nviscous flows.
The principal model we study was proposed by O. A. Ladyzhenskaya\, althoug
h the techniques we develop here apply to other fluids having\na shear dep
endent (or gradient dependent) viscosity. Taking advantage of the\nPontrya
gin Minimum Principle\, we utilize a bootstrapping argument to prove\nthat
regular controls to the forced linearized Stokes problem exist\, as long\
nas the initial data in turn has enough regularity. From there\, we extend
the\nresult to the nonlinear problem. As a byproduct\, we devise a quasi-
Newton\nalgorithm to compute the states and a control\, which we prove to
converge in\nan appropriate sense. We finish the work with some numerical
experiments.\nThis is a joint work with P. de Carvalho\, J. Límaco and D.
Menezes.\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/13/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jeffrey Park (University Alaska Fairbanks)
DTSTART:20201027T163000Z
DTEND:20201027T170000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/14
DESCRIPTION:Title: Inverse Problem for the Schrödinger Equation with Non-self-adj
oint Matrix Potential\nby Jeffrey Park (University Alaska Fairbanks) a
s part of Control in Times of Crisis. Online seminar.\n\n\nAbstract\nWe co
nsider the dynamical system with boundary control for the vector Schrödin
ger equation on\nthe interval with a non-self-adjoint matrix potential. Fo
r this system\, we study the inverse problem\nof recovering the matrix pot
ential from the dynamical Neumann-to-Dirichlet operator. We first provide\
na method to recover spectral data for the Schrödinger system. We then de
velop a strategy for solving\nthe inverse problem using this method with o
ther techniques of the Boundary Control method. This talk\nis based on joi
nt work with Sergei Avdonin\, Alexander Mikhaylov\, and Victor Mikhaylov.\
n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/14/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kevin Le Balc'h (Université Bordeaux)
DTSTART:20201110T160000Z
DTEND:20201110T163000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/15
DESCRIPTION:Title: Exponential bounds for gradient of solutions to linear elliptic
and parabolic equations.\nby Kevin Le Balc'h (Université Bordeaux) a
s part of Control in Times of Crisis. Online seminar.\n\n\nAbstract\nIn th
is talk\, I begin by introducing the Landis conjecture on exponential deca
y of solutions to\nelliptic equations. I recall the (ongoing) story of thi
s conjecture and its link with sharp observability\nestimates for solution
s to elliptic and parabolic equations. Motivated by "a dual version of the
Landis\nconjecture"\, I present new exponential bounds for gradient of so
lutions to elliptic and parabolic equations.\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/15/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jon Asier Barcena-Petisco (Universidad Autonoma de Madrid)
DTSTART:20201110T163000Z
DTEND:20201110T170000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/16
DESCRIPTION:Title: Averaged dynamics and control for heat equations with random di
ffusion\nby Jon Asier Barcena-Petisco (Universidad Autonoma de Madrid)
as part of Control in Times of Crisis. Online seminar.\n\n\nAbstract\nIn
this talk we deal with the averaged dynamics for heat equations in the deg
enerate case\nwhere the diffusivity coefficient\, assumed to be constant\,
is allowed to take the null value. First we\nprove that the averaged dyna
mics is analytic. This allows to show that\, most often\, the averaged\ndy
namics enjoys the property of unique continuation and is approximately con
trollable. We then\ndetermine if the averaged dynamics is actually null co
ntrollable or not depending on how the density\nof averaging behaves when
the diffusivity vanishes. In the critical density threshold the dynamics\n
of the average is similar to the 1/2-fractional Laplacian\, which is well-
known to be critical in the\ncontext of the controllability of fractional
diffusion processes. Null controllability then fails (resp.\nholds) when t
he density weights more (resp. less) in the null diffusivity regime than i
n this critical\nregime.\nThis talk is based on joint work with Enrique Zu
azua.\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/16/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ozkan Ozer (Western Kentucky University)
DTSTART:20201201T160000Z
DTEND:20201201T171500Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/17
DESCRIPTION:Title: Introduction of Novel PDE Models of Certain Smart Material Syst
ems and Diving into Related Controllability Issues\nby Ozkan Ozer (Wes
tern Kentucky University) as part of Control in Times of Crisis. Online se
minar.\n\n\nAbstract\nIn this talk\, novel PDE models for single-layer and
multi-layer smart material beam systems will\nbe introduced. These models
mainly couple the longitudinal and/or transverse vibrations of layers wit
h\nthe electro-magnetism due to Maxwell's equations and/or thermal effects
. Recent results on the exact\nboundary observability and controllability\
, stabilizability will be discussed and certain mathematical\nhurdles will
be addressed. Even though some of these PDE models are known to be exactl
y observable\, their\napproximations by the Finite-Element and Finite-Diff
erence methods are not able to mimic this behavior with\nrespect to the di
scretization parameter. Recent results on the application of a filtering t
echnique and the\nissues due to the non-compact coupling between the syste
m equations and different wave speeds through the\nlayers will be discusse
d. Finally\, if the time allows\, recently published Wolfram's Demonstrati
on Projects\nwill be shown briefly and related future directions will be a
ddressed.\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/17/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Julie Valein (Université Lorraine)
DTSTART:20201215T160000Z
DTEND:20201215T171500Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/18
DESCRIPTION:Title: Some results about the stability and the controllability of the
KdV equation\nby Julie Valein (Université Lorraine) as part of Contr
ol in Times of Crisis. Online seminar.\n\n\nAbstract\nIn this talk\, I pre
sent some recent results about the Korteweg-de Vries equation obtained wit
h Lucie Baudouin (LAAS\, Toulouse)\, Eduardo Cerpa (Pontificia Univ. Catol
ica de Chile) and Emmanuelle Crépeau (Univ. Grenoble Alpes). First\, we s
how the robustness of the exponential stability of the KdV equation with r
espect to the delay in the boundary or the internal feedbacks\, and we sho
w that the behavior is not the same in the two situations. Then we study t
he boundary controllability of the KdV equation on a tree network.\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/18/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cristina Urbani (Gran Sasso Science Institute)
DTSTART:20201124T160000Z
DTEND:20201124T163000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/19
DESCRIPTION:Title: A constructive algorithm for building mixing coupling potential
s. Application to bilinear control.\nby Cristina Urbani (Gran Sasso Sc
ience Institute) as part of Control in Times of Crisis. Online seminar.\n\
n\nAbstract\nDespite the importance of control systems governed by a bilin
ear control for the description of phenomena that could not be modeled by
additive controls\, stabilization and\ncontrollability problems for such k
ind of systems have not been so widely studied in the\nliterature as it ha
ppens for boundary and locally distributed controls. The main reasons of\n
this fact might be found in the intrinsic nonlinear nature of such problem
s and furthermore\,\nfor controls that are scalar functions of time\, in a
n ineluctable obstruction for exact controllability under very general ass
umptions presented in the celebrated work of Ball\, Marsden\nand Slemrod [
3].\nBy violating one of the hypotheses of [3]\, Beauchard and collaborato
rs have succeeded in\nproving exact controllability for hyperbolic systems
in a topology stronger than the natural\none for such problems [4\, 5]. W
hereas\, for evolution equations of parabolic type\, results\nof rapid sta
bilization and exact controllability to a trajectory have been demonstrate
d by\nAlabau-Boussouira\, Cannarsa and Urbani [1\, 2]. A common step that
can be found in all\nthe aforementioned works is the proof of the exact co
ntrollability of the system obtained\nby linearization of the nonlinear pr
oblem along the reference trajectory. It turns out that\na necessary condi
tion on the rank of the potential must be satisfied. However\, even if the
\ngenericity of such assumption has been proved for instance in [5]\, it i
s in practice difficult to\nexhibit examples of suitable potentials.\nThe
aim of this talk is to present a constructive algorithm that provides a in
finite class\nof functions that fulfill the required property.\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/19/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Wencel Valega Mackenzie (University Tennessee Knoxville)
DTSTART:20201124T163000Z
DTEND:20201124T170000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/20
DESCRIPTION:Title: Resource Allocation in an Open Ecosystem\nby Wencel Valega
Mackenzie (University Tennessee Knoxville) as part of Control in Times of
Crisis. Online seminar.\n\n\nAbstract\nIn this talk\, we propose a reactio
n-diffusion population model to study the effect of resource\nallocation i
n an ecosystem where resources are allowed to have their own dynamics in s
pace and time.\nWe also formulate and solve an optimal control problem app
lied to the resource allocation model where\nthe inflow of resources is th
e control. The goal is to maximize the abundance of the population while\n
minimizing the cost of inflow resource allocation. Our model can capture h
abitat heterogeneity to represent\nchanges in the population instead of as
suming the resource level remains homogeneous in the habitat. Some\nnumeri
cal simulations will be shown to illustrate the dynamics of the model.\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/20/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jorge Zavaleta (Universidad Nacional Autónoma de México)
DTSTART:20201208T160000Z
DTEND:20201208T163000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/21
DESCRIPTION:Title: Radial basis function methods with hybrid kernels applied to so
lve control problems.\nby Jorge Zavaleta (Universidad Nacional Autóno
ma de México) as part of Control in Times of Crisis. Online seminar.\n\n\
nAbstract\nRadial basis functions (RBFs) methods have been widely applied
to several fields in science and engineering in recent years. These method
s are well known for attaining an exponential rate of convergence for some
kernels and are flexible in dealing with complex boundaries in several di
mensions. Hybrid kernels presented by Mishra et al. (2018) have\, among al
l the available ones used in RBFs methods\, the advantage of simultaneousl
y maintaining a good condition number of the Gram matrices while preservin
g the exponential rate of convergence for the error. Also\, they have been
successfully applied to obtain the numerical solution of stationary and e
volutionary partial differential equations using radial basis-finite diffe
rences (RBF-FD) (Mishra et al. 2019). Although the numerical stability of
these methods has been studied\, there are still theoretical and practical
aspects to explain. In this talk\, we present an overview of radial basis
function methods with hybrid kernels and how they are applied to solve co
ntrol problems numerically. We will show some recent results which have be
en obtained for solving distributed optimal control problems and null cont
rollability of the Stokes equation via local RBF methods.\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/21/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lucas Machado
DTSTART:20201208T163000Z
DTEND:20201208T170000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/22
DESCRIPTION:Title: Some control results for Stokes equations with memory.\nby
Lucas Machado as part of Control in Times of Crisis. Online seminar.\n\n\n
Abstract\nStokes equations have been studied since many years and its unde
rstanding is very relevant from the mathe- matical and physical viewpoint.
In this talk\, we will consider the Stokes equations in the presence of a
n integro- differential term (integral in time and differential in space)
called memory term. We will study the boundary null controllability proble
m (to steer the flow to the rest at an arbitrarily small time) for the Sto
kes equations with memory in the two and three dimensional cases. Precisel
y\, we will construct explicitly initial conditions such that the null con
trollability does not hold even if the controls act on the whole boundary.
Moreover\, we also prove that this negative result holds for distributed
controls. Finally\, we will present some issues which remain open.\nJoint
work with Enrique Fernández-Cara (University of Sevilla) and Diego A. Sou
za (University of Sevilla).\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/22/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nicolas Burq (U Paris Sud\, France)
DTSTART:20210114T160000Z
DTEND:20210114T171500Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/23
DESCRIPTION:Title: Propagation of smallness and control for heat equations.\nb
y Nicolas Burq (U Paris Sud\, France) as part of Control in Times of Crisi
s. Online seminar.\n\n\nAbstract\nIn this talk I will present some results
on the propagation of smallness properties for solutions to heat equation
s. I will consider spectral projector estimates for the Laplace operator w
ith Dirichlet or Neumann boundary conditions on a Riemanian manifold with
or without boundary and on $R^d$. I will show that using as a black box th
e new approach for the propagation of smallness from Logunov-Malinnikova a
llows to extend the spectral projector type estimates from Jerison-Lebeau
from localisation on open set to localisation on arbitrary sets of non zer
o Lebesgue measure\; I will actually go beyond and consider sets of non va
nishing $d- \\delta$\, ($ \\delta >0$ small enough) Hausdorf measure. I wi
ll show that these new spectral projector estimates allow to extend the Lo
gunov-Malinnikova's propagation of smallness results to solutions to heat
equations. Finally I will apply these results to the null controlability o
f heat equations with controls localised on sets of positive Lebesgue meas
ure. A main novelty here with respect to previous results is that we can d
rop previous the constant coefficient assumptions of the Laplace operator
(or analyticity assumption) and deal with Lipschitz coefficients. Another
important novelty is that we get the first (non one dimensional) exact con
trolability results with controls supported on zero measure sets and at di
screte times.\nThis is a joint work with I. Moyano (université de Nice).\
n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/23/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Denilson Menezes (U.F. Fluminense\, Brazil)
DTSTART:20210121T160000Z
DTEND:20210121T163000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/24
DESCRIPTION:Title: On equilibria for generalized Boussinesq fluid-chemical models
with multiplicative controls\nby Denilson Menezes (U.F. Fluminense\, B
razil) as part of Control in Times of Crisis. Online seminar.\n\n\nAbstrac
t\nWe investigate equilibria for multi-objective optimal control problems
in a model of\nfluid-chemical interactions. The action of the controls occ
urs multiplicatively\, a pertinent\nassumption for certain practical circu
mstances\, e.g.\, the study of ocean pollution control.\nFor a single agen
t\, we provide a characterization of the Pareto front in terms of a suitab
le\nclass of minimization problems\, each of which being equivalent to sol
ving an optimality system.\nIn the multi-agent competitive setting\, each
agent seeks to minimize her performance criteria\nto attain Pareto optimal
ity\, and we investigate Nash equilibria in this context. We derive and\na
nalyze the resulting optimality system in the latter framework.\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/24/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mihai Nechita (INRIA Paris)
DTSTART:20210121T163000Z
DTEND:20210121T170000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/25
DESCRIPTION:Title: Unique continuation problems and stabilized finite element meth
ods\nby Mihai Nechita (INRIA Paris) as part of Control in Times of Cri
sis. Online seminar.\n\n\nAbstract\nWe consider the unique continuation pr
oblem for elliptic PDEs with data given in an interior subset of the domai
n. This is an ill-posed problem that arises often in inverse problems and
control theory.\nWe focus on the Helmholtz and the convection-diffusion eq
uations and present first conditional stability estimates that are explici
t in the physical parameters. Under a geometric convexity assumption\, we
show that for the Helmholtz equation the stability constants grow at most
linearly in the wave number.\nWe then discuss a finite element method base
d on a discretise-then-regularise approach. We cast the problem into PDE-c
onstrained optimisation with discrete regularisation inspired from stabili
sed FEM. Our focus is on the interior penalty stabilisation. Convergence r
ates are obtained by applying the continuum stability estimates to the app
roximation error and controlling the residual through stabilisation. For c
onvection-dominated problems\, we obtain sharper weighted error estimates
along the characteristics of the convective field through the data region.
\nThe results are illustrated by numerical examples. This is joint work wi
th Erik Burman and Lauri Oksanen.\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/25/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lauri Oksanen (UC London\, UK)
DTSTART:20210128T160000Z
DTEND:20210128T171500Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/26
DESCRIPTION:Title: Spacetime finite element methods for control problems subject t
o the wave equation\nby Lauri Oksanen (UC London\, UK) as part of Cont
rol in Times of Crisis. Online seminar.\n\n\nAbstract\nWe consider the nul
l controllability problem for the wave equation\, and analyse a stabilized
finite element method formulated on a global\, unstructured spacetime mes
h. We prove error estimates for the control function given by the computat
ional method. The proofs are based on the regularity properties of the con
trol function given by the Hilbert Uniqueness Method\, together with the s
tability properties of the numerical scheme. The talk is based on joint wo
rk with Erik Burman\, Ali Feizmohammadi and Arnaud Münch.\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/26/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cristobal Merono (Madrid\, Spain)
DTSTART:20210204T160000Z
DTEND:20210204T163000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/27
DESCRIPTION:Title: The fixed angle scattering problem with a first order perturbat
ion\nby Cristobal Merono (Madrid\, Spain) as part of Control in Times
of Crisis. Online seminar.\n\n\nAbstract\nIn this talk we present recent r
esults on the inverse scattering problem for the Schrödinger equation tha
t consists in determining a magnetic field and electric potential from sca
ttering measurements corresponding to finitely many plane waves. The main
result shows that the coefficients are uniquely determined by 2n measureme
nts up to a natural gauge. We also show that one can recover the full firs
t order term for a related equation having no gauge invariance\, and that
it is possible to reduce the number of measurements if the coefficients ha
ve certain symmetries. This work extends the fixed angle scattering result
s of Rakesh and M. Salo to Hamiltonians with first order perturbations\, a
nd it is based on wave equation methods and Carleman estimates.\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/27/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Shengquan Xiang (EPFL\, Switzerland)
DTSTART:20210204T163000Z
DTEND:20210204T170000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/28
DESCRIPTION:Title: Quantitative rapid and finite time stabilization of the heat eq
uation\nby Shengquan Xiang (EPFL\, Switzerland) as part of Control in
Times of Crisis. Online seminar.\n\n\nAbstract\nThe finite time stabilizat
ion of the 1D heat equation was proved by Coron-Nguyen (2015) via backstep
ping\, while the multidimensional cases remained open. Inspired by Coron-T
rélat's Lyapunov approach (2004) we construct explicit stationary feedbac
k laws that quantitatively rapidly stabilize the heat equation\, where the
spectral inequality of Lebeau-Robbiano type (1995) is naturally adapted.
Next we construct explicit controls leading to the null controllability sh
aring optimal costs $e^{C/T}$\, and further prove the finite time stabiliz
ation. We also talk about the stabilization of Navier-Stokes equations.\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/28/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Rafael Vazquez (U Sevilla\, Spain)
DTSTART:20210211T160000Z
DTEND:20210211T171500Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/29
DESCRIPTION:Title: Backstepping for PDEs: fundamentals and some recent results
\nby Rafael Vazquez (U Sevilla\, Spain) as part of Control in Times of Cri
sis. Online seminar.\n\n\nAbstract\nIn this talk\, I will start by reviewi
ng the backstepping method for boundary control of Partial Differential Eq
uations (PDEs)\, its main ingredients (selection of a judicious target sys
tem\, use of an invertible integral transformation\, solution of the corre
sponding kernel equations) and in particular its usefulness for coupled pa
rabolic and hyperbolic systems. The rest of the talk is then devoted to so
me recent results on a few topics: the Rijke tube\, modelled by coupled hy
perbolic PDEs and ODEs\, where some preliminary experimental results are a
vailable\; extensions to n-dimensional parabolic systems\, which present c
hallenges for backstepping since it is not clear how to pose the system tr
ansformation\; and coupled parabolic-hyperbolic systems\, for which few re
sults are available due to the difficulty in finding the right target syst
em and transformation. These results have been obtained in collaborations
with several authors\, including M. Krstic\, G. A. de Andrade\, J. Zang\,
G. Chen\, and others\, which will be credited during the talk.\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/29/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Irena Lasiecka (U Memphis\, US)
DTSTART:20210225T160000Z
DTEND:20210225T171500Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/30
DESCRIPTION:Title: Control of a third order in time dynamics governing nonlinear a
coustic waves - a view from the boundary\nby Irena Lasiecka (U Memphis
\, US) as part of Control in Times of Crisis. Online seminar.\n\nAbstract:
TBA\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/30/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Fredi Tröltzsch (TU Berlin\, Germany)
DTSTART:20210311T160000Z
DTEND:20210311T171500Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/31
DESCRIPTION:Title: On Optimal Control Problems with Controls Appearing Nonlinearly
in an Elliptic State Equation\nby Fredi Tröltzsch (TU Berlin\, Germa
ny) as part of Control in Times of Crisis. Online seminar.\n\nAbstract: TB
A\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/31/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Assia Benabdallah (U Marseille\, France)
DTSTART:20210325T160000Z
DTEND:20210325T171500Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/32
DESCRIPTION:Title: Control of parabolic equations\nby Assia Benabdallah (U Mar
seille\, France) as part of Control in Times of Crisis. Online seminar.\n\
n\nAbstract\nhttp://ctcseminar.mat.utfsm.cl/AbstractBenabdallah.pdf\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/32/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Armand Koenig (U Paris-Dauphine\, France)
DTSTART:20210408T150000Z
DTEND:20210408T161500Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/33
DESCRIPTION:by Armand Koenig (U Paris-Dauphine\, France) as part of Contro
l in Times of Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/33/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mohammad Akil
DTSTART:20210422T150000Z
DTEND:20210422T153000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/34
DESCRIPTION:Title: (CANCELED) Stability results of some coupled wave systems with
different kinds of localized damping.\nby Mohammad Akil as part of Con
trol in Times of Crisis. Online seminar.\n\n\nAbstract\nFirst\, we conside
r a system of two wave equations coupled by velocities in one-dimensional
space with one boundary fractional damping and we prove that the energy of
our system decays polynomially with different rates. Second\, we investig
ate the stabilization of a locally coupled wave equations with only one in
ternal viscoelastic damping of Kelvin-Voigt type and we prove that the ene
rgy of our system decays polynomially with rate 1/t. Finally\, we investig
ate the stabilization of a locally coupled wave equations with local visco
elastic damping of past history type acting only in one equation via non s
mooth coefficients and we establish the exponential stability of the solut
ion if and only if the two waves have the same speed of propagation. In ca
se of different speed propagation\, we prove that the energy of our system
decays polynomially with rate 1/t.\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/34/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dante Kalise (School of Mathematical Sciences\, University of Nott
ingham)
DTSTART:20210429T150000Z
DTEND:20210429T161500Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/35
DESCRIPTION:Title: High-dimensional Hamilton-Jacobi PDEs: Approximation\, Represen
tation\, and Learning.\nby Dante Kalise (School of Mathematical Scienc
es\, University of Nottingham) as part of Control in Times of Crisis. Onli
ne seminar.\n\n\nAbstract\nHamilton-Jacobi PDEs are a central object in op
timal control and differential games\, enabling the computation of robust
controls in feedback form. High-dimensional HJ PDEs naturally arise in the
feedback synthesis for high-dimensional control systems\, and their numer
ical solution must be sought outside the framework provided by standard gr
id-based discretizations. In this talk\, I will discuss the construction n
ovel computational methods for approximating high-dimensional HJ PDEs. In
the first part of the talk\, I will present a numerical method based on te
nsor decompositions. Such a compressed representation of the value functio
n has a complexity that scales linearly with respect to the dimension of t
he control system\, allowing the solution of control problems over very hi
gh-dimensional states. In the second part of the talk\, I will discuss the
construction of a class of causality-free\, data-driven methods which cir
cumvent the numerical solution of the HJ PDE. I will address the generatio
n of a synthetic dataset based on the use of representation formulas (such
as Lax-Hopf or Pontryagin’s Maximum Principle)\, which is then fed
into a high-dimensional sparse polynomial model for training. The use of
representation formulas providing gradient information is fundamental to i
ncrease the data efficiency of the method. I will present applications in
control of nonlinear PDEs and agent-based models.\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/35/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christophe Zhang (U Erlangen\, Germany)
DTSTART:20210218T160000Z
DTEND:20210218T163000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/36
DESCRIPTION:by Christophe Zhang (U Erlangen\, Germany) as part of Control
in Times of Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/36/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cyril Letrouit (ENS Paris)
DTSTART:20210218T163000Z
DTEND:20210218T170000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/37
DESCRIPTION:Title: Exact controllability properties of subelliptic wave and Schrö
dinger equations\nby Cyril Letrouit (ENS Paris) as part of Control in
Times of Crisis. Online seminar.\n\n\nAbstract\nWe present several results
concerning exact controllability and observability properties of subellip
tic PDEs\, i.e.\, PDEs driven by a subelliptic Laplacian. Our first result
is that subelliptic wave equations are never controllable/observable. The
n\, considering various families of subelliptic operators\, we explain tha
t subelliptic Schrödinger-type equations can be controllable in any time\
, or never controllable\, or controllable only for sufficiently large time
. This last part was done in collaboration with Chenmin Sun and Clotilde F
ermanian Kammerer. The tools used in this presentation come from various f
ields: sub-Riemannian geometry\, semi-classical analysis\, spectral theory
and non-commutative harmonic analysis\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/37/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yacine Mokhtari (Besancon\, France)
DTSTART:20210304T160000Z
DTEND:20210304T163000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/38
DESCRIPTION:Title: Boundary stabilization of the 1-D wave equation on non-cylindri
cal domains\nby Yacine Mokhtari (Besancon\, France) as part of Control
in Times of Crisis. Online seminar.\n\n\nAbstract\nBoundary stabilization
of the 1-D wave equation on non-cylindrical domains (or domains with movi
ng boundaries) is discussed. By using a time-varying feedback law acting o
n one side of the boundary\, we provide a necessary and sufficient conditi
on for the stabilization at any desired decay rate. Furthermore\, the infl
uence of the boundary shape on the decay rate is clarified. Some particula
r examples are discussed.\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/38/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Thomas Ian Ashley (Sevilla\, Spain)
DTSTART:20210304T163000Z
DTEND:20210304T170000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/39
DESCRIPTION:Title: New methods and results for the optimisation of solar power tow
er plants\nby Thomas Ian Ashley (Sevilla\, Spain) as part of Control i
n Times of Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/39/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lina Guan (Grenoble\, France)
DTSTART:20210506T150000Z
DTEND:20210506T153000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/40
DESCRIPTION:by Lina Guan (Grenoble\, France) as part of Control in Times o
f Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/40/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Constantinos Kitsos (Université de Toulouse\, France)
DTSTART:20210318T160000Z
DTEND:20210318T163000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/41
DESCRIPTION:Title: Output feedback control of an under-actuated and under-observed
cascade system of linear Korteweg-de Vries equations.\nby Constantino
s Kitsos (Université de Toulouse\, France) as part of Control in Times of
Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/41/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Exequiel Mallea Zepeda (Universidad de Tarapacá)
DTSTART:20210318T163500Z
DTEND:20210318T170500Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/42
DESCRIPTION:Title: Optimal control problems related to chemo-repulsion systems.\nby Exequiel Mallea Zepeda (Universidad de Tarapacá) as part of Control
in Times of Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/42/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Daniel Faraco (UA Madrid\, Spain)
DTSTART:20210415T150000Z
DTEND:20210415T160000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/43
DESCRIPTION:Title: Homogenization and Inverse Problems\nby Daniel Faraco (UA M
adrid\, Spain) as part of Control in Times of Crisis. Online seminar.\n\nA
bstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/43/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Swann Marx (Nantes\, France)
DTSTART:20210422T150000Z
DTEND:20210422T160000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/44
DESCRIPTION:Title: One-dimensional wave equation with set-valued damping: well-pos
edness\, asymptotic stability\, and decay rates.\nby Swann Marx (Nante
s\, France) as part of Control in Times of Crisis. Online seminar.\n\n\nAb
stract\nIn this presentation\, the focus will be on a one-dimensional wave
equation with a set-valued boundary damping. This (general) framework all
ows to consider nonlinear dampings such as saturations (i.e. nonlinearitie
s modeling amplitude constraints) or dry dampings (a nonlinearity given by
a sign function). The approach that will be presented consists in transfo
rming the one-dimensional wave equation as a scalar discrete nonlinear dif
ferential inclusion. It is a general approach that could be applied on mor
e general systems. It allows to obtain several results: a necessary and su
fficient condition for the well-posedness\; asymptotic stability in L^p ty
pe functional spaces\; optimality of decay rates. The well-posedness resul
t and some asymptotic stability results will be presented during the prese
ntation. It is a joint work with Yacine Chitour and Guilherme Mazanti.\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/44/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alessandro Alla (PUC\, Rio\, Brazil)
DTSTART:20210513T150000Z
DTEND:20210513T161500Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/45
DESCRIPTION:Title: HJB-RBF based approach for the control of PDEs\nby Alessand
ro Alla (PUC\, Rio\, Brazil) as part of Control in Times of Crisis. Online
seminar.\n\n\nAbstract\nSemi-Lagranian schemes for discretization of the
dynamic programming principle are based on a time discretization projected
on a state-space grid. The use of a structured grid makes this approach n
ot feasible for high-dimensional problems due to the curse of dimensionali
ty. Here\, we present a new approach for infinite horizon optimal control
problems where the value function is computed using Radial Basis Functions
(RBF) and Shepard’s moving least squares approximation method on s
cattered grids. We propose a new method to generate a scattered mesh drive
n by the dynamics and the selection of the shape parameter in the RBF usin
g an optimization routine. Numerical tests for high dimensional problems w
ill show the effectiveness of the proposed method. Joint work with H. Oliv
eira (PUC-Rio\, Brazil) and G. Santin (FBK\, Italy).\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/45/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Imene Djebour (U. Lorraine\, France)
DTSTART:20210520T150000Z
DTEND:20210520T153000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/46
DESCRIPTION:Title: Local null controllability of a fluid-rigid body interaction pr
oblem with Navier slip boundary conditions\nby Imene Djebour (U. Lorra
ine\, France) as part of Control in Times of Crisis. Online seminar.\n\nAb
stract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/46/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Esteban Hernández (Universidad Técnica Federico Santa María Val
paraíso\, Chile)
DTSTART:20210520T153000Z
DTEND:20210520T160000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/47
DESCRIPTION:Title: Rapid stabilization of a unstable heat equation under boundary
disturbance\nby Esteban Hernández (Universidad Técnica Federico Sant
a María Valparaíso\, Chile) as part of Control in Times of Crisis. Onlin
e seminar.\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/47/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Delphine Bresch-Pietri (Mines Paristech\, Paris)
DTSTART:20210527T150000Z
DTEND:20210527T161500Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/48
DESCRIPTION:Title: Control of linear and nonlinear systems subject to a random inp
ut delay\nby Delphine Bresch-Pietri (Mines Paristech\, Paris) as part
of Control in Times of Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/48/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Larisa Beilina (Chalmers\, Sweden)
DTSTART:20210610T150000Z
DTEND:20210610T161500Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/49
DESCRIPTION:Title: Finite element analysis of an inverse problem for Maxwell's equ
ations with application to microwave thermometry\nby Larisa Beilina (C
halmers\, Sweden) as part of Control in Times of Crisis. Online seminar.\n
\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/49/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Stephen Guffey (U. Memphis\, US)
DTSTART:20210603T150000Z
DTEND:20210603T153000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/50
DESCRIPTION:Title: Local Null Controllability for a Chemotactic Model for Bacteria
l Infection in a Chronic Wound\nby Stephen Guffey (U. Memphis\, US) as
part of Control in Times of Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/50/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jehan Alswaihli
DTSTART:20210603T153000Z
DTEND:20210603T160000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/51
DESCRIPTION:Title: Iteration of inverse problems and data assimilation techniques
for neural field equations.\nby Jehan Alswaihli as part of Control in
Times of Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/51/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Frédéric Marbach (U Rennes\, France)
DTSTART:20210624T150000Z
DTEND:20210624T161500Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/52
DESCRIPTION:Title: Expansion for nonlinear systems\, error estimates and convergen
ce issues\nby Frédéric Marbach (U Rennes\, France) as part of Contro
l in Times of Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/52/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Franck Boyer (U Toulouse\, France)
DTSTART:20210708T150000Z
DTEND:20210708T161500Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/53
DESCRIPTION:by Franck Boyer (U Toulouse\, France) as part of Control in Ti
mes of Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/53/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hugo Parada
DTSTART:20210617T150000Z
DTEND:20210617T153000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/54
DESCRIPTION:Title: Global Well-posedness of KdV equation on a Star Shaped Network
and an application to saturated stabilization\nby Hugo Parada as part
of Control in Times of Crisis. Online seminar.\n\n\nAbstract\nIn this talk
we deal with the global well-posedness and stability of the nonlinear and
linear Korteweg-de Vries (KdV) equation on a finite star-shaped network b
y acting with saturated controls. We obtain the global well-posedness by u
sing the a Sharp Kato smoothing property for the linear case and then usin
g somes estimates and a fixed point argument we deal with the nonlinear sy
stem. Finally we obtain the semi-global exponential stability of two diffe
rent kinds of saturation using a contradiction argument to prove appropria
ted observability inequalities.\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/54/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Luca Saluzzi (GSSI\, Italy)
DTSTART:20210617T153000Z
DTEND:20210617T160000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/55
DESCRIPTION:by Luca Saluzzi (GSSI\, Italy) as part of Control in Times of
Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/55/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jose Henrique Rodrigues (U. Memphis\, USA)
DTSTART:20210701T150000Z
DTEND:20210701T153000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/56
DESCRIPTION:Title: On the well-posedness and stabilization of a nonlinear structur
al-acoustic interaction problem\nby Jose Henrique Rodrigues (U. Memphi
s\, USA) as part of Control in Times of Crisis. Online seminar.\n\nAbstrac
t: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/56/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christian Montoya (U. of Dubrovnik\, Croatia)
DTSTART:20210701T153000Z
DTEND:20210701T160000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/57
DESCRIPTION:Title: Robust Stackelberg controllability for the Kuramoto-Sivashinsky
equation\nby Christian Montoya (U. of Dubrovnik\, Croatia) as part of
Control in Times of Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/57/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Rodrigo Lecaros (UTFSM\, Chile)
DTSTART:20210715T150000Z
DTEND:20210715T153000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/58
DESCRIPTION:by Rodrigo Lecaros (UTFSM\, Chile) as part of Control in Times
of Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/58/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Andrew Wallon Green (Washington U\, St Louis\, USA)
DTSTART:20210715T153000Z
DTEND:20210715T160000Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/59
DESCRIPTION:by Andrew Wallon Green (Washington U\, St Louis\, USA) as part
of Control in Times of Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/59/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mikko Salo (U Jyväskylä\, Finland)
DTSTART:20211007T150000Z
DTEND:20211007T161500Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/60
DESCRIPTION:Title: Controlling elliptic PDE and applications to inverse problems\nby Mikko Salo (U Jyväskylä\, Finland) as part of Control in Times of
Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/60/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mariano Mateos (U. de Oviedo\, Spain)
DTSTART:20211209T160000Z
DTEND:20211209T171500Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/61
DESCRIPTION:Title: Optimal control problems with non-smooth integral constraints i
n space.\nby Mariano Mateos (U. de Oviedo\, Spain) as part of Control
in Times of Crisis. Online seminar.\n\n\nAbstract\nSparsity is often a des
irable property for the solution of least squares problems that may appear
\, for instance\, in image processing or optimal control problems. Two pos
sible techniques to obtain sparse solutions are the following: we can eith
er penalize the functional with an $L^1$-type term or impose an upper boun
d on the norm of the control variable in $L^1$. There are several examples
in the literature about optimal control problems where the usual Tikhonov
-regularized tracking type cost functional is penalized\, by instance\, wi
th the norm of the control variable in $L^1(\\Omega)$ --for problems gover
ned by elliptic equations-- or in $L^2(0\,T\;L^1(\\Omega))$ --in the case
of problems governed by parabolic equations--. In this talk\, we discuss t
he second technique: we impose an upper bound on the norm of the control v
ariable in $L^1(Omega)$ --for problems governed by elliptic equations-- or
in $L^\\infty(0\,T\;L^1(\\Omega))$ --in the case of problems governed by
parabolic equations--. Notice that this is a quite natural condition: the
``amount of control'' that you can feed into the system at each instant of
time is usually limited by technological or economic reasons. On the othe
r hand\, the lack of differentiability of the constraint leads to special
difficulties in the analysis of the problem that require new techniques of
proof. We first prove existence of solution\, and obtain necessary first
order optimality conditions\, from which we deduce the sparsity properties
of local solutions. Second order necessary and sufficient optimality cond
itions with a minimal gap are also obtained. In the second part of the tal
k\, we show the correct way to discretize the problem\, so that the discre
te solutions still satisfy the sparsity properties\, prove convergence and
obtain error estimates. Finally\, we discuss optimization methods and pre
sent several examples. In order to avoid some of the most technical detail
s\, we will focus on a problem governed by a semilinear elliptic equation\
, and will comment on the differences and extra difficulties that appear w
hen the governing equation is parabolic. This presentation is based on a c
ollaboration with E. Casas (U. de Cantabria\, Spain) and K. Kunisch (U. Gr
az\, Austria).\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/61/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Emilia Fridman (Tel-Aviv University)
DTSTART:20220113T160000Z
DTEND:20220113T171500Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/62
DESCRIPTION:Title: Finite-dimensional observer-based control of parabolic PDEs
\nby Emilia Fridman (Tel-Aviv University) as part of Control in Times of C
risis. Online seminar.\n\n\nAbstract\nFinite-dimensional observer-based co
ntroller design for PDEs is a challenging problem. In this talk\, construc
tion of such controllers via modal decomposition method for parabolic $1D$
PDEs will be presented. We will start with a linear heat equation\, where
at least one of the control or observation operators is bounded. We will
proceed with the case of both unbounded operators\, where dynamic extensio
n is helpful. Here the results for Kuramoto-Sivashinskii and heat equation
s will be discussed. For both equations we use eigenvalues and eigenfuncti
ons of a Sturm-Liouville operator. The controller design is based on $N_0$
unstable modes\, whereas the observer dimension $N$ is not smaller than $
N_0$. We suggest a direct Lyapunov approach to the closed-loop system\, wh
ich results in an LMI whose elements depend on $N$. The value of $N$ and t
he decay rate are obtained from the LMI. We prove that the LMIs are always
feasible for large enough $N$. Delayed and sampled-data implementations o
f the controllers and extensions to semilinear PDEs will be discussed. Thi
s is joint work with my PhD student Rami Katz.\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/62/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Pierre Lissy (U. Paris Dauphine\, France)
DTSTART:20211118T160000Z
DTEND:20211118T171500Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/63
DESCRIPTION:Title: Insensitizing controls for the heat equation with respect to bo
undary variations\nby Pierre Lissy (U. Paris Dauphine\, France) as par
t of Control in Times of Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/63/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Otared Kavian (U. Versailles\, France)
DTSTART:20220303T160000Z
DTEND:20220303T171500Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/64
DESCRIPTION:Title: Remarks on the Cauchy problem for the Laplacian and the Approxi
mate Lagrangian controllability of the Euler Equation\nby Otared Kavia
n (U. Versailles\, France) as part of Control in Times of Crisis. Online s
eminar.\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/64/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jérôme Le Rousseau (U. Sorbonne Paris Nord\, France)
DTSTART:20220407T150000Z
DTEND:20220407T161500Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/65
DESCRIPTION:by Jérôme Le Rousseau (U. Sorbonne Paris Nord\, France) as p
art of Control in Times of Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/65/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ana Leonor Silvestre (Universidade de Lisboa)
DTSTART:20220210T160000Z
DTEND:20220210T171500Z
DTSTAMP:20260404T111000Z
UID:CTCSeminar/66
DESCRIPTION:Title: Optimal boundary control for drag minimization in a fluid-rigid
body interaction\nby Ana Leonor Silvestre (Universidade de Lisboa) as
part of Control in Times of Crisis. Online seminar.\n\n\nAbstract\nConsid
er a rigid body ${\\mathcal S} \\subset {\\mathbb R}^3$ immersed in a Navi
er-Stokes liquid and the motion of the body-fluid interaction system descr
ibed from a reference frame attached to ${\\mathcal S}$. We are interested
in the steady motions of this coupled system\, where the region occupied
by the fluid is the exterior domain $\\Omega = {\\mathbb R}^3 \\setminus {
\\mathcal S}$. \nWe are interested in the following problem: how to use bo
undary controls\, acting on the whole $\\partial\\Omega$ or just on a port
ion $\\Gamma$ of $\\partial\\Omega$\, to generate a self-propelled motion
of ${\\mathcal S}$ with a target velocity $V(x):=\\xi+\\omega \\times x$ a
nd minimize the drag about ${\\mathcal S}$.\nThis is joint work with Toshi
aki Hishida (Nagoya University\, Japan) and Tak\\'eo Takahashi (INRIA Nanc
y-Grand Est\, France).\n
LOCATION:https://stable.researchseminars.org/talk/CTCSeminar/66/
END:VEVENT
END:VCALENDAR