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BEGIN:VEVENT
SUMMARY:Jean-Michel Coron (Université Pierre et Marie Curie)
DTSTART:20200908T150000Z
DTEND:20200908T161500Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/1
DESCRIPTION:Title: Rapid and finite-time stabilization\nby Jean-Michel Coron (Universi
té Pierre et Marie Curie) as part of Control in Times of Crisis. Online s
eminar.\n\n\nAbstract\nWe present various results on the rapid and the fin
ite-time stabilization of control systems.\nThis includes control systems
in finite dimension (with an application to a quadcopter\nsliding on a pla
ne) as well as control systems modeled by means of partial differential eq
uations (1-D linear hyperbolic systems\, 1-D linear parabolic equations an
d KdV equations).\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Claudia Moreno (Université Paris-Saclay (UVSQ))
DTSTART:20200915T150000Z
DTEND:20200915T153000Z
DTSTAMP:20260422T225754Z
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 Control
in Times of Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Irene Marín-Gayte (Universidad de Sevilla)
DTSTART:20200915T153000Z
DTEND:20200915T160000Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/3
DESCRIPTION:Title: Theoretical and numerical bi-objective optimal control: Nash equilibria
\nby Irene Marín-Gayte (Universidad de Sevilla) as part of Control in
Times of Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marius Tucsnak (Université de Bordeaux)
DTSTART:20200922T150000Z
DTEND:20200922T160000Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/4
DESCRIPTION:Title: Does the boundary controlled heat equation define an exactly controllab
le system?\nby Marius Tucsnak (Université de Bordeaux) as part of Con
trol in Times of Crisis. Online seminar.\n\n\nAbstract\nIt is commonly acc
epted in the control theory of PDEs that parabolic equations\, due to the
smoothing effect\,\ndo not determine exactly controllable systems when con
trolled from the boundary. The aim of this presentation\nis to explain how
the heat semigroup can be restricted to an appropriate function space on
which\, when\ncontrolled from the boundary\, it could determine an exactly
controllable systems. To this aim\, we first recall\nsome abstract concep
ts concerning reachability in an infinite dimensional context\, insisting
on the general\nrelevance of the concept of reachable space. We next descr
ibe some recent advances on the reachable space of\nthe boundary controlle
d heat equation in one space dimension. We next discuss the exact controll
ability of this\nsystem in appropriate spaces of analytic functions. We gi
ve applications in determining the reachable space\nwith smooth inputs\, w
ith possible application to nonlinear problems. Finally\, we discuss the p
ossible\nimplications of our methods to improve the existing estimates of
the control constant in small time.\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jose A. Villa ((UNAM\, Mexico))
DTSTART:20200929T150000Z
DTEND:20200929T153000Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/5
DESCRIPTION:Title: Hierarchical control for the semilinear heat equation.\nby Jose A.
Villa ((UNAM\, Mexico)) as part of Control in Times of Crisis. Online semi
nar.\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gilcenio Rodrigues ((U F di Piaui\, Brazil))
DTSTART:20200929T153000Z
DTEND:20200929T160000Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/6
DESCRIPTION:Title: Boundary controllability of a one-dimensional phase-field system with o
ne control force\nby Gilcenio Rodrigues ((U F di Piaui\, Brazil)) as p
art of Control in Times of Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Piermarco Cannarsa (Università degli Studi di Roma "Tor Vergata")
DTSTART:20201006T150000Z
DTEND:20201006T160000Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/7
DESCRIPTION:Title: Bilinear control for evolution equations\nby Piermarco Cannarsa (Un
iversità degli Studi di Roma "Tor Vergata") as part of Control in Times o
f Crisis. Online seminar.\n\n\nAbstract\nThe observability for the classic
al Schrödinger equation usually holds for very short\ntime\, under suitab
le geometric conditions. However\, it is not the case when the underlying
geometry\nis sub-elliptic. In this talk we consider the Schrodinger equati
on associated with the Bouendi-\nGrushin operator. The Bouendi-Grushin ope
rator is a subelliptic operator which is degenerate\nalong a line. In the
Bouendi case\, the associated Schrödinger equation exhibits a transport e
ffect\nwhich leads to a "sub-elliptic" geometric control condition and a m
inimal time to ensure the\nobservability. For general Bouendi-Grushin with
stronger sub-elliptic effect\, the observability for\nthe Schrödinger eq
uation is never true. These observability results can be seen from a semi-
\nclassical point of view\, through a optimal resolvent esti- mate. Conseq
uently\, our resolvent\nestimate leads to an energy decay rate for the ass
ociated damped wave equation. This talk is\nbased on a joint work with Nic
olas Burq and another with Cyril Letrouit.\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Chenmin Sun (U. Cergy)
DTSTART:20201013T153000Z
DTEND:20201013T160000Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/8
DESCRIPTION:Title: Classical and semi-classical observability for the Bouendi-Grushin oper
ator\nby Chenmin Sun (U. Cergy) as part of Control in Times of Crisis.
Online seminar.\n\n\nAbstract\nThe observability for the classical Schrö
dinger equation usually holds for very short\ntime\, under suitable geomet
ric conditions. However\, it is not the case when the underlying geometry\
nis sub-elliptic. In this talk we consider the Schrodinger equation associ
ated with the Bouendi-\nGrushin operator. The Bouendi-Grushin operator is
a subelliptic operator which is degenerate\nalong a line. In the Bouendi c
ase\, the associated Schrödinger equation exhibits a transport effect\nwh
ich leads to a "sub-elliptic" geometric control condition and a minimal ti
me to ensure the\nobservability. For general Bouendi-Grushin with stronger
sub-elliptic effect\, the observability for\nthe Schrödinger equation is
never true. These observability results can be seen from a semi-\nclassic
al point of view\, through a optimal resolvent esti- mate. Consequently\,
our resolvent\nestimate leads to an energy decay rate for the associated d
amped wave equation. This talk is\nbased on a joint work with Nicolas Burq
and another with Cyril Letrouit.\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Amaury Hayat (Ecole des Ponts Paristech)
DTSTART:20201013T150000Z
DTEND:20201013T153000Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/9
DESCRIPTION:Title: Stabilization of some nonlinear hyperbolic PDEs\nby Amaury Hayat (E
cole des Ponts Paristech) as part of Control in Times of Crisis. Online se
minar.\n\n\nAbstract\nAbstract: We consider two types of systems : density
-velocity systems and traffic flows.\nDensity-velocity systems encompass m
any physical equations: isentropic Euler equations\,\nSaint-Venant equatio
ns\, osmosis model\, etc. We show that these equations have a local\ndissi
pative property that allows to stabilize any steady-state with boundary fe
edback\ncontrols\, provided some physical assumption. Moreover\, this hold
s even if we have no\nknowledge of some the system parameters or with a si
ngle control.\nTraffic flows are very interesting from a control perspecti
ve. In many situations the\nsteady-states are unstable\, leading to travel
ling waves\, known as stop-and-go waves by\nengineers or simply jam. From
a mathematical point of view they can be represented by\ncoupled hyperboli
c PDEs with solutions of class BV. We will present on-going work showing\n
how one can try to stabilize the steady-states using autonomous vehicles\,
i.e. pointwise\ncontrols. This leads to a system of ODEs and PDEs coupled
by a flux relation\, which provoke\nnon-classical shocks. The solutions a
re then at most BV and the control is contained in the\ndynamics of the OD
Es.\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/9/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Karl Kunisch (U Grass\, Austria)
DTSTART:20201020T150000Z
DTEND:20201020T161500Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/10
DESCRIPTION:Title: Solution Concepts for Optimal Feedback Control of Nonlinear Partial Di
fferential Equations\nby Karl Kunisch (U Grass\, Austria) as part of C
ontrol in Times of Crisis. Online seminar.\n\n\nAbstract\nFeedback control
of nonlinear systems in practice is still frequently based on linearisati
on\nand subsequent treatment by efficient Riccati solvers. Here we want to
follow different directions.\n\nI concentrate on three solution strategie
s which aim at the nonlinear control system directly. The\nfirst one is ba
sed on higher order Taylor expansions of the value function and leads to c
ontrols\nwhich rely on generalized Ljapunov equations.\n\nThe second appro
ach is based on Newton steps applied to the HJB equation. Combined with sp
ectral\ntechniques and tensor calculus this allows to solve HJB equations
up to dimension 100. The results\nare demonstrated for the control of disc
retized Fokker Planck equations.\n\nThe third technique circumvents the di
rect solution of the HJB equation. Rather a neural network\nis trained by
means of a succinctly chosen ansatz and it is proven that it approximates
the solution\nto the HJB equation as the dimension of the network is incre
ased.\n\nThis work relies on collaborations with T.Breiten\, S.Dolgov\, D.
Kalise\, L.Pfeiffer\, and D.Walter.\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Belhassen Dehman (Fac. des Sciences de Tunis\, Tunisia)
DTSTART:20201103T160000Z
DTEND:20201103T171500Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/11
DESCRIPTION:Title: Controllability of the Wave Equation on a rough compact manifold.\
nby Belhassen Dehman (Fac. des Sciences de Tunis\, Tunisia) as part of Con
trol in Times of Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Suzanne Lenhart (University of Tennessee\, USA)
DTSTART:20201117T160000Z
DTEND:20201117T171500Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/12
DESCRIPTION:Title: Optimal control for management of aquatic population models\nby Su
zanne Lenhart (University of Tennessee\, USA) as part of Control in Times
of Crisis. Online seminar.\n\n\nAbstract\nOptimal control techniques of or
dinary and partial differential equations will be introduced\nto consider
management strategies for two different aquatic populations. In the first
example\,\nmanaging invasive species in rivers can be assisted by adjustme
nt of flow rates. Control of a flow\nrate in a partial differential equati
on model for a population in a river will be used to keep the\npopulation
from moving upstream. The second example represents a food chain on the Tu
rkish coast of\nthe Black Sea. Using data from the anchovy landings in Tur
key\, optimal control of the harvesting\nrate of the anchovy population in
a system of three ordinary differential equations (anchovy\,\njellyfish a
nd zooplankton) will give management strategies.\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/12/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yuri Thamsten (Universidade Fluminense)
DTSTART:20201027T160000Z
DTEND:20201027T163000Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/13
DESCRIPTION:Title: Local null controllability of a class of non-Newtonian incompressible
viscous fluids\nby Yuri Thamsten (Universidade Fluminense) as part of
Control in Times of Crisis. Online seminar.\n\n\nAbstract\nWe investigate
the null controllability property of systems that\nmathematically describe
the dynamics of some non-Newtonian incompressible\nviscous flows. The pri
ncipal model we study was proposed by O. A. Ladyzhenskaya\, although the t
echniques we develop here apply to other fluids having\na shear dependent
(or gradient dependent) viscosity. Taking advantage of the\nPontryagin Min
imum Principle\, we utilize a bootstrapping argument to prove\nthat regula
r controls to the forced linearized Stokes problem exist\, as long\nas the
initial data in turn has enough regularity. From there\, we extend the\nr
esult to the nonlinear problem. As a byproduct\, we devise a quasi-Newton\
nalgorithm to compute the states and a control\, which we prove to converg
e in\nan appropriate sense. We finish the work with some numerical experim
ents.\nThis is a joint work with P. de Carvalho\, J. Límaco and D. Meneze
s.\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/13/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jeffrey Park (University Alaska Fairbanks)
DTSTART:20201027T163000Z
DTEND:20201027T170000Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/14
DESCRIPTION:Title: Inverse Problem for the Schrödinger Equation with Non-self-adjoint Ma
trix Potential\nby Jeffrey Park (University Alaska Fairbanks) as part
of Control in Times of Crisis. Online seminar.\n\n\nAbstract\nWe consider
the dynamical system with boundary control for the vector Schrödinger equ
ation on\nthe interval with a non-self-adjoint matrix potential. For this
system\, we study the inverse problem\nof recovering the matrix potential
from the dynamical Neumann-to-Dirichlet operator. We first provide\na meth
od to recover spectral data for the Schrödinger system. We then develop a
strategy for solving\nthe inverse problem using this method with other te
chniques of the Boundary Control method. This talk\nis based on joint work
with Sergei Avdonin\, Alexander Mikhaylov\, and Victor Mikhaylov.\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/14/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kevin Le Balc'h (Université Bordeaux)
DTSTART:20201110T160000Z
DTEND:20201110T163000Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/15
DESCRIPTION:Title: Exponential bounds for gradient of solutions to linear elliptic and pa
rabolic equations.\nby Kevin Le Balc'h (Université Bordeaux) as part
of Control in Times of Crisis. Online seminar.\n\n\nAbstract\nIn this talk
\, I begin by introducing the Landis conjecture on exponential decay of so
lutions to\nelliptic equations. I recall the (ongoing) story of this conje
cture and its link with sharp observability\nestimates for solutions to el
liptic and parabolic equations. Motivated by "a dual version of the Landis
\nconjecture"\, I present new exponential bounds for gradient of solutions
to elliptic and parabolic equations.\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/15/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jon Asier Barcena-Petisco (Universidad Autonoma de Madrid)
DTSTART:20201110T163000Z
DTEND:20201110T170000Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/16
DESCRIPTION:Title: Averaged dynamics and control for heat equations with random diffusion
\nby Jon Asier Barcena-Petisco (Universidad Autonoma de Madrid) as par
t of Control in Times of Crisis. Online seminar.\n\n\nAbstract\nIn this ta
lk we deal with the averaged dynamics for heat equations in the degenerate
case\nwhere the diffusivity coefficient\, assumed to be constant\, is all
owed to take the null value. First we\nprove that the averaged dynamics is
analytic. This allows to show that\, most often\, the averaged\ndynamics
enjoys the property of unique continuation and is approximately controllab
le. We then\ndetermine if the averaged dynamics is actually null controlla
ble or not depending on how the density\nof averaging behaves when the dif
fusivity vanishes. In the critical density threshold the dynamics\nof the
average is similar to the 1/2-fractional Laplacian\, which is well-known t
o be critical in the\ncontext of the controllability of fractional diffusi
on processes. Null controllability then fails (resp.\nholds) when the dens
ity weights more (resp. less) in the null diffusivity regime than in this
critical\nregime.\nThis talk is based on joint work with Enrique Zuazua.\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/16/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ozkan Ozer (Western Kentucky University)
DTSTART:20201201T160000Z
DTEND:20201201T171500Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/17
DESCRIPTION:Title: Introduction of Novel PDE Models of Certain Smart Material Systems and
Diving into Related Controllability Issues\nby Ozkan Ozer (Western Ke
ntucky University) as part of Control in Times of Crisis. Online seminar.\
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 with\nthe
electro-magnetism due to Maxwell's equations and/or thermal effects. Recen
t results on the exact\nboundary observability and controllability\, stabi
lizability will be discussed and certain mathematical\nhurdles will be add
ressed. Even though some of these PDE models are known to be exactly obser
vable\, their\napproximations by the Finite-Element and Finite-Difference
methods are not able to mimic this behavior with\nrespect to the discretiz
ation parameter. Recent results on the application of a filtering techniqu
e and the\nissues due to the non-compact coupling between the system equat
ions and different wave speeds through the\nlayers will be discussed. Fina
lly\, if the time allows\, recently published Wolfram's Demonstration Proj
ects\nwill be shown briefly and related future directions will be addresse
d.\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/17/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Julie Valein (Université Lorraine)
DTSTART:20201215T160000Z
DTEND:20201215T171500Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/18
DESCRIPTION:Title: Some results about the stability and the controllability of the KdV eq
uation\nby Julie Valein (Université Lorraine) as part of Control in T
imes of Crisis. Online seminar.\n\n\nAbstract\nIn this talk\, I present so
me recent results about the Korteweg-de Vries equation obtained with Lucie
Baudouin (LAAS\, Toulouse)\, Eduardo Cerpa (Pontificia Univ. Catolica de
Chile) and Emmanuelle Crépeau (Univ. Grenoble Alpes). First\, we show the
robustness of the exponential stability of the KdV equation with respect
to the delay in the boundary or the internal feedbacks\, and we show that
the behavior is not the same in the two situations. Then we study the boun
dary controllability of the KdV equation on a tree network.\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/18/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cristina Urbani (Gran Sasso Science Institute)
DTSTART:20201124T160000Z
DTEND:20201124T163000Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/19
DESCRIPTION:Title: A constructive algorithm for building mixing coupling potentials. Appl
ication to bilinear control.\nby Cristina Urbani (Gran Sasso Science I
nstitute) as part of Control in Times of Crisis. Online seminar.\n\n\nAbst
ract\nDespite the importance of control systems governed by a bilinear con
trol for the description of phenomena that could not be modeled by additiv
e controls\, stabilization and\ncontrollability problems for such kind of
systems have not been so widely studied in the\nliterature as it happens f
or boundary and locally distributed controls. The main reasons of\nthis fa
ct might be found in the intrinsic nonlinear nature of such problems and f
urthermore\,\nfor controls that are scalar functions of time\, in an inelu
ctable obstruction for exact controllability under very general assumption
s presented in the celebrated work of Ball\, Marsden\nand Slemrod [3].\nBy
violating one of the hypotheses of [3]\, Beauchard and collaborators have
succeeded in\nproving exact controllability for hyperbolic systems in a t
opology stronger than the natural\none for such problems [4\, 5]. Whereas\
, for evolution equations of parabolic type\, results\nof rapid stabilizat
ion and exact controllability to a trajectory have been demonstrated by\nA
labau-Boussouira\, Cannarsa and Urbani [1\, 2]. A common step that can be
found in all\nthe aforementioned works is the proof of the exact controlla
bility of the system obtained\nby linearization of the nonlinear problem a
long the reference trajectory. It turns out that\na necessary condition on
the rank of the potential must be satisfied. However\, even if the\ngener
icity of such assumption has been proved for instance in [5]\, it is in pr
actice difficult to\nexhibit examples of suitable potentials.\nThe aim of
this talk is to present a constructive algorithm that provides a infinite
class\nof functions that fulfill the required property.\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/19/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Wencel Valega Mackenzie (University Tennessee Knoxville)
DTSTART:20201124T163000Z
DTEND:20201124T170000Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/20
DESCRIPTION:Title: Resource Allocation in an Open Ecosystem\nby Wencel Valega Mackenz
ie (University Tennessee Knoxville) as part of Control in Times of Crisis.
Online seminar.\n\n\nAbstract\nIn this talk\, we propose a reaction-diffu
sion population model to study the effect of resource\nallocation in an ec
osystem where resources are allowed to have their own dynamics in space an
d time.\nWe also formulate and solve an optimal control problem applied to
the resource allocation model where\nthe inflow of resources is the contr
ol. The goal is to maximize the abundance of the population while\nminimiz
ing the cost of inflow resource allocation. Our model can capture habitat
heterogeneity to represent\nchanges in the population instead of assuming
the resource level remains homogeneous in the habitat. Some\nnumerical sim
ulations will be shown to illustrate the dynamics of the model.\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/20/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jorge Zavaleta (Universidad Nacional Autónoma de México)
DTSTART:20201208T160000Z
DTEND:20201208T163000Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/21
DESCRIPTION:Title: Radial basis function methods with hybrid kernels applied to solve con
trol problems.\nby Jorge Zavaleta (Universidad Nacional Autónoma de M
éxico) as part of Control in Times of Crisis. Online seminar.\n\n\nAbstra
ct\nRadial basis functions (RBFs) methods have been widely applied to seve
ral fields in science and engineering in recent years. These methods are w
ell known for attaining an exponential rate of convergence for some kernel
s and are flexible in dealing with complex boundaries in several dimension
s. Hybrid kernels presented by Mishra et al. (2018) have\, among all the a
vailable ones used in RBFs methods\, the advantage of simultaneously maint
aining a good condition number of the Gram matrices while preserving the e
xponential rate of convergence for the error. Also\, they have been succes
sfully applied to obtain the numerical solution of stationary and evolutio
nary partial differential equations using radial basis-finite differences
(RBF-FD) (Mishra et al. 2019). Although the numerical stability of these m
ethods has been studied\, there are still theoretical and practical aspect
s to explain. In this talk\, we present an overview of radial basis functi
on methods with hybrid kernels and how they are applied to solve control p
roblems numerically. We will show some recent results which have been obta
ined for solving distributed optimal control problems and null controllabi
lity of the Stokes equation via local RBF methods.\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/21/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lucas Machado
DTSTART:20201208T163000Z
DTEND:20201208T170000Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/22
DESCRIPTION:Title: Some control results for Stokes equations with memory.\nby Lucas M
achado as part of Control in Times of Crisis. Online seminar.\n\n\nAbstrac
t\nStokes equations have been studied since many years and its understandi
ng is very relevant from the mathe- matical and physical viewpoint. In thi
s talk\, we will consider the Stokes equations in the presence of an integ
ro- differential term (integral in time and differential in space) called
memory term. We will study the boundary null controllability problem (to s
teer the flow to the rest at an arbitrarily small time) for the Stokes equ
ations with memory in the two and three dimensional cases. Precisely\, we
will construct explicitly initial conditions such that the null controllab
ility does not hold even if the controls act on the whole boundary. Moreov
er\, we also prove that this negative result holds for distributed control
s. Finally\, we will present some issues which remain open.\nJoint work wi
th Enrique Fernández-Cara (University of Sevilla) and Diego A. Souza (Uni
versity of Sevilla).\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/22/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nicolas Burq (U Paris Sud\, France)
DTSTART:20210114T160000Z
DTEND:20210114T171500Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/23
DESCRIPTION:Title: Propagation of smallness and control for heat equations.\nby Nicol
as Burq (U Paris Sud\, France) as part of Control in Times of Crisis. Onli
ne seminar.\n\n\nAbstract\nIn this talk I will present some results on the
propagation of smallness properties for solutions to heat equations. I wi
ll consider spectral projector estimates for the Laplace operator with Dir
ichlet or Neumann boundary conditions on a Riemanian manifold with or with
out boundary and on $R^d$. I will show that using as a black box the new a
pproach for the propagation of smallness from Logunov-Malinnikova allows t
o extend the spectral projector type estimates from Jerison-Lebeau from lo
calisation on open set to localisation on arbitrary sets of non zero Lebes
gue measure\; I will actually go beyond and consider sets of non vanishing
$d- \\delta$\, ($ \\delta >0$ small enough) Hausdorf measure. I will show
that these new spectral projector estimates allow to extend the Logunov-M
alinnikova's propagation of smallness results to solutions to heat equatio
ns. Finally I will apply these results to the null controlability of heat
equations with controls localised on sets of positive Lebesgue measure. A
main novelty here with respect to previous results is that we can drop pre
vious the constant coefficient assumptions of the Laplace operator (or ana
lyticity assumption) and deal with Lipschitz coefficients. Another importa
nt novelty is that we get the first (non one dimensional) exact controlabi
lity results with controls supported on zero measure sets and at discrete
times.\nThis is a joint work with I. Moyano (université de Nice).\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/23/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Denilson Menezes (U.F. Fluminense\, Brazil)
DTSTART:20210121T160000Z
DTEND:20210121T163000Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/24
DESCRIPTION:Title: On equilibria for generalized Boussinesq fluid-chemical models with mu
ltiplicative controls\nby Denilson Menezes (U.F. Fluminense\, Brazil)
as part of Control in Times of Crisis. Online seminar.\n\n\nAbstract\nWe i
nvestigate equilibria for multi-objective optimal control problems in a mo
del of\nfluid-chemical interactions. The action of the controls occurs mul
tiplicatively\, a pertinent\nassumption for certain practical circumstance
s\, e.g.\, the study of ocean pollution control.\nFor a single agent\, we
provide a characterization of the Pareto front in terms of a suitable\ncla
ss of minimization problems\, each of which being equivalent to solving an
optimality system.\nIn the multi-agent competitive setting\, each agent s
eeks to minimize her performance criteria\nto attain Pareto optimality\, a
nd we investigate Nash equilibria in this context. We derive and\nanalyze
the resulting optimality system in the latter framework.\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/24/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mihai Nechita (INRIA Paris)
DTSTART:20210121T163000Z
DTEND:20210121T170000Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/25
DESCRIPTION:Title: Unique continuation problems and stabilized finite element methods
\nby Mihai Nechita (INRIA Paris) as part of Control in Times of Crisis. On
line seminar.\n\n\nAbstract\nWe consider the unique continuation problem f
or elliptic PDEs with data given in an interior subset of the domain. This
is an ill-posed problem that arises often in inverse problems and control
theory.\nWe focus on the Helmholtz and the convection-diffusion equations
and present first conditional stability estimates that are explicit in th
e physical parameters. Under a geometric convexity assumption\, we show th
at for the Helmholtz equation the stability constants grow at most linearl
y in the wave number.\nWe then discuss a finite element method based on a
discretise-then-regularise approach. We cast the problem into PDE-constrai
ned optimisation with discrete regularisation inspired from stabilised FEM
. Our focus is on the interior penalty stabilisation. Convergence rates ar
e obtained by applying the continuum stability estimates to the approximat
ion error and controlling the residual through stabilisation. For convecti
on-dominated problems\, we obtain sharper weighted error estimates along t
he characteristics of the convective field through the data region.\nThe r
esults are illustrated by numerical examples. This is joint work with Erik
Burman and Lauri Oksanen.\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/25/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lauri Oksanen (UC London\, UK)
DTSTART:20210128T160000Z
DTEND:20210128T171500Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/26
DESCRIPTION:Title: Spacetime finite element methods for control problems subject to the w
ave equation\nby Lauri Oksanen (UC London\, UK) as part of Control in
Times of Crisis. Online seminar.\n\n\nAbstract\nWe consider the null contr
ollability problem for the wave equation\, and analyse a stabilized finite
element method formulated on a global\, unstructured spacetime mesh. We p
rove error estimates for the control function given by the computational m
ethod. The proofs are based on the regularity properties of the control fu
nction given by the Hilbert Uniqueness Method\, together with the stabilit
y properties of the numerical scheme. The talk is based on joint work with
Erik Burman\, Ali Feizmohammadi and Arnaud Münch.\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/26/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cristobal Merono (Madrid\, Spain)
DTSTART:20210204T160000Z
DTEND:20210204T163000Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/27
DESCRIPTION:Title: The fixed angle scattering problem with a first order perturbation
\nby Cristobal Merono (Madrid\, Spain) as part of Control in Times of Cris
is. Online seminar.\n\n\nAbstract\nIn this talk we present recent results
on the inverse scattering problem for the Schrödinger equation that consi
sts in determining a magnetic field and electric potential from scattering
measurements corresponding to finitely many plane waves. The main result
shows that the coefficients are uniquely determined by 2n measurements up
to a natural gauge. We also show that one can recover the full first order
term for a related equation having no gauge invariance\, and that it is p
ossible to reduce the number of measurements if the coefficients have cert
ain symmetries. This work extends the fixed angle scattering results of Ra
kesh and M. Salo to Hamiltonians with first order perturbations\, and it i
s based on wave equation methods and Carleman estimates.\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/27/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Shengquan Xiang (EPFL\, Switzerland)
DTSTART:20210204T163000Z
DTEND:20210204T170000Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/28
DESCRIPTION:Title: Quantitative rapid and finite time stabilization of the heat equation<
/a>\nby Shengquan Xiang (EPFL\, Switzerland) as part of Control in Times o
f Crisis. Online seminar.\n\n\nAbstract\nThe finite time stabilization of
the 1D heat equation was proved by Coron-Nguyen (2015) via backstepping\,
while the multidimensional cases remained open. Inspired by Coron-Trélat'
s Lyapunov approach (2004) we construct explicit stationary feedback laws
that quantitatively rapidly stabilize the heat equation\, where the spectr
al inequality of Lebeau-Robbiano type (1995) is naturally adapted. Next we
construct explicit controls leading to the null controllability sharing o
ptimal costs $e^{C/T}$\, and further prove the finite time stabilization.
We also talk about the stabilization of Navier-Stokes equations.\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/28/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Rafael Vazquez (U Sevilla\, Spain)
DTSTART:20210211T160000Z
DTEND:20210211T171500Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/29
DESCRIPTION:Title: Backstepping for PDEs: fundamentals and some recent results\nby Ra
fael Vazquez (U Sevilla\, Spain) as part of Control in Times of Crisis. On
line seminar.\n\n\nAbstract\nIn this talk\, I will start by reviewing the
backstepping method for boundary control of Partial Differential Equations
(PDEs)\, its main ingredients (selection of a judicious target system\, u
se of an invertible integral transformation\, solution of the correspondin
g kernel equations) and in particular its usefulness for coupled parabolic
and hyperbolic systems. The rest of the talk is then devoted to some rece
nt results on a few topics: the Rijke tube\, modelled by coupled hyperboli
c PDEs and ODEs\, where some preliminary experimental results are availabl
e\; extensions to n-dimensional parabolic systems\, which present challeng
es for backstepping since it is not clear how to pose the system transform
ation\; and coupled parabolic-hyperbolic systems\, for which few results a
re available due to the difficulty in finding the right target system and
transformation. These results have been obtained in collaborations with se
veral authors\, including M. Krstic\, G. A. de Andrade\, J. Zang\, G. Chen
\, and others\, which will be credited during the talk.\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/29/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Irena Lasiecka (U Memphis\, US)
DTSTART:20210225T160000Z
DTEND:20210225T171500Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/30
DESCRIPTION:Title: Control of a third order in time dynamics governing nonlinear acoustic
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://researchseminars.org/talk/CTCSeminar/30/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Fredi Tröltzsch (TU Berlin\, Germany)
DTSTART:20210311T160000Z
DTEND:20210311T171500Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/31
DESCRIPTION:Title: On Optimal Control Problems with Controls Appearing Nonlinearly in an
Elliptic State Equation\nby Fredi Tröltzsch (TU Berlin\, Germany) as
part of Control in Times of Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/31/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Assia Benabdallah (U Marseille\, France)
DTSTART:20210325T160000Z
DTEND:20210325T171500Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/32
DESCRIPTION:Title: Control of parabolic equations\nby Assia Benabdallah (U Marseille\
, France) as part of Control in Times of Crisis. Online seminar.\n\n\nAbst
ract\nhttp://ctcseminar.mat.utfsm.cl/AbstractBenabdallah.pdf\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/32/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Armand Koenig (U Paris-Dauphine\, France)
DTSTART:20210408T150000Z
DTEND:20210408T161500Z
DTSTAMP:20260422T225754Z
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://researchseminars.org/talk/CTCSeminar/33/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mohammad Akil
DTSTART:20210422T150000Z
DTEND:20210422T153000Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/34
DESCRIPTION:Title: (CANCELED) Stability results of some coupled wave systems with differe
nt kinds of localized damping.\nby Mohammad Akil as part of Control in
Times of Crisis. Online seminar.\n\n\nAbstract\nFirst\, we consider a sys
tem of two wave equations coupled by velocities in one-dimensional space w
ith one boundary fractional damping and we prove that the energy of our sy
stem decays polynomially with different rates. Second\, we investigate the
stabilization of a locally coupled wave equations with only one internal
viscoelastic damping of Kelvin-Voigt type and we prove that the energy of
our system decays polynomially with rate 1/t. Finally\, we investigate the
stabilization of a locally coupled wave equations with local viscoelastic
damping of past history type acting only in one equation via non smooth c
oefficients and we establish the exponential stability of the solution if
and only if the two waves have the same speed of propagation. In case of d
ifferent speed propagation\, we prove that the energy of our system decays
polynomially with rate 1/t.\n
LOCATION:https://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:20260422T225754Z
UID:CTCSeminar/35
DESCRIPTION:Title: High-dimensional Hamilton-Jacobi PDEs: Approximation\, Representation\
, and Learning.\nby Dante Kalise (School of Mathematical Sciences\, Un
iversity of Nottingham) as part of Control in Times of Crisis. Online semi
nar.\n\n\nAbstract\nHamilton-Jacobi PDEs are a central object in optimal c
ontrol and differential games\, enabling the computation of robust control
s in feedback form. High-dimensional HJ PDEs naturally arise in the feedba
ck synthesis for high-dimensional control systems\, and their numerical so
lution must be sought outside the framework provided by standard grid-base
d discretizations. In this talk\, I will discuss the construction novel co
mputational methods for approximating high-dimensional HJ PDEs. In the fir
st part of the talk\, I will present a numerical method based on tensor de
compositions. Such a compressed representation of the value function has a
complexity that scales linearly with respect to the dimension of the cont
rol system\, allowing the solution of control problems over very high-dime
nsional states. In the second part of the talk\, I will discuss the constr
uction of a class of causality-free\, data-driven methods which circumvent
the numerical solution of the HJ PDE. I will address the generation 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 represe
ntation formulas providing gradient information is fundamental to increase
the data efficiency of the method. I will present applications in control
of nonlinear PDEs and agent-based models.\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/35/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christophe Zhang (U Erlangen\, Germany)
DTSTART:20210218T160000Z
DTEND:20210218T163000Z
DTSTAMP:20260422T225754Z
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://researchseminars.org/talk/CTCSeminar/36/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cyril Letrouit (ENS Paris)
DTSTART:20210218T163000Z
DTEND:20210218T170000Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/37
DESCRIPTION:Title: Exact controllability properties of subelliptic wave and Schrödinger
equations\nby Cyril Letrouit (ENS Paris) as part of Control in Times o
f Crisis. Online seminar.\n\n\nAbstract\nWe present several results concer
ning exact controllability and observability properties of subelliptic PDE
s\, i.e.\, PDEs driven by a subelliptic Laplacian. Our first result is tha
t subelliptic wave equations are never controllable/observable. Then\, con
sidering various families of subelliptic operators\, we explain that subel
liptic Schrödinger-type equations can be controllable in any time\, or ne
ver controllable\, or controllable only for sufficiently large time. This
last part was done in collaboration with Chenmin Sun and Clotilde Fermania
n Kammerer. The tools used in this presentation come from various fields:
sub-Riemannian geometry\, semi-classical analysis\, spectral theory and no
n-commutative harmonic analysis\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/37/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yacine Mokhtari (Besancon\, France)
DTSTART:20210304T160000Z
DTEND:20210304T163000Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/38
DESCRIPTION:Title: Boundary stabilization of the 1-D wave equation on non-cylindrical dom
ains\nby Yacine Mokhtari (Besancon\, France) as part of Control in Tim
es of Crisis. Online seminar.\n\n\nAbstract\nBoundary stabilization of the
1-D wave equation on non-cylindrical domains (or domains with moving boun
daries) is discussed. By using a time-varying feedback law acting on one s
ide of the boundary\, we provide a necessary and sufficient condition for
the stabilization at any desired decay rate. Furthermore\, the influence o
f the boundary shape on the decay rate is clarified. Some particular examp
les are discussed.\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/38/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Thomas Ian Ashley (Sevilla\, Spain)
DTSTART:20210304T163000Z
DTEND:20210304T170000Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/39
DESCRIPTION:Title: New methods and results for the optimisation of solar power tower plan
ts\nby Thomas Ian Ashley (Sevilla\, Spain) as part of Control in Times
of Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/39/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lina Guan (Grenoble\, France)
DTSTART:20210506T150000Z
DTEND:20210506T153000Z
DTSTAMP:20260422T225754Z
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://researchseminars.org/talk/CTCSeminar/40/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Constantinos Kitsos (Université de Toulouse\, France)
DTSTART:20210318T160000Z
DTEND:20210318T163000Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/41
DESCRIPTION:Title: Output feedback control of an under-actuated and under-observed cascad
e system of linear Korteweg-de Vries equations.\nby Constantinos Kitso
s (Université de Toulouse\, France) as part of Control in Times of Crisis
. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/41/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Exequiel Mallea Zepeda (Universidad de Tarapacá)
DTSTART:20210318T163500Z
DTEND:20210318T170500Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/42
DESCRIPTION:Title: Optimal control problems related to chemo-repulsion systems.\nby E
xequiel Mallea Zepeda (Universidad de Tarapacá) as part of Control in Tim
es of Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/42/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Daniel Faraco (UA Madrid\, Spain)
DTSTART:20210415T150000Z
DTEND:20210415T160000Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/43
DESCRIPTION:Title: Homogenization and Inverse Problems\nby Daniel Faraco (UA Madrid\,
Spain) as part of Control in Times of Crisis. Online seminar.\n\nAbstract
: TBA\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/43/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Swann Marx (Nantes\, France)
DTSTART:20210422T150000Z
DTEND:20210422T160000Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/44
DESCRIPTION:Title: One-dimensional wave equation with set-valued damping: well-posedness\
, asymptotic stability\, and decay rates.\nby Swann Marx (Nantes\, Fra
nce) as part of Control in Times of Crisis. Online seminar.\n\n\nAbstract\
nIn this presentation\, the focus will be on a one-dimensional wave equati
on with a set-valued boundary damping. This (general) framework allows to
consider nonlinear dampings such as saturations (i.e. nonlinearities model
ing amplitude constraints) or dry dampings (a nonlinearity given by a sign
function). The approach that will be presented consists in transforming t
he one-dimensional wave equation as a scalar discrete nonlinear differenti
al inclusion. It is a general approach that could be applied on more gener
al systems. It allows to obtain several results: a necessary and sufficien
t condition for the well-posedness\; asymptotic stability in L^p type func
tional spaces\; optimality of decay rates. The well-posedness result and s
ome asymptotic stability results will be presented during the presentation
. It is a joint work with Yacine Chitour and Guilherme Mazanti.\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/44/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alessandro Alla (PUC\, Rio\, Brazil)
DTSTART:20210513T150000Z
DTEND:20210513T161500Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/45
DESCRIPTION:Title: HJB-RBF based approach for the control of PDEs\nby Alessandro Alla
(PUC\, Rio\, Brazil) as part of Control in Times of Crisis. Online semina
r.\n\n\nAbstract\nSemi-Lagranian schemes for discretization of the dynamic
programming principle are based on a time discretization projected on a s
tate-space grid. The use of a structured grid makes this approach not feas
ible for high-dimensional problems due to the curse of dimensionality. Her
e\, we present a new approach for infinite horizon optimal control problem
s where the value function is computed using Radial Basis Functions (RBF)
and Shepard’s moving least squares approximation method on scattere
d grids. We propose a new method to generate a scattered mesh driven by th
e dynamics and the selection of the shape parameter in the RBF using an op
timization routine. Numerical tests for high dimensional problems will sho
w the effectiveness of the proposed method. Joint work with H. Oliveira (P
UC-Rio\, Brazil) and G. Santin (FBK\, Italy).\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/45/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Imene Djebour (U. Lorraine\, France)
DTSTART:20210520T150000Z
DTEND:20210520T153000Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/46
DESCRIPTION:Title: Local null controllability of a fluid-rigid body interaction problem w
ith Navier slip boundary conditions\nby Imene Djebour (U. Lorraine\, F
rance) as part of Control in Times of Crisis. Online seminar.\n\nAbstract:
TBA\n
LOCATION:https://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:20260422T225754Z
UID:CTCSeminar/47
DESCRIPTION:Title: Rapid stabilization of a unstable heat equation under boundary disturb
ance\nby Esteban Hernández (Universidad Técnica Federico Santa Marí
a Valparaíso\, Chile) as part of Control in Times of Crisis. Online semin
ar.\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/47/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Delphine Bresch-Pietri (Mines Paristech\, Paris)
DTSTART:20210527T150000Z
DTEND:20210527T161500Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/48
DESCRIPTION:Title: Control of linear and nonlinear systems subject to a random input dela
y\nby Delphine Bresch-Pietri (Mines Paristech\, Paris) as part of Cont
rol in Times of Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/48/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Larisa Beilina (Chalmers\, Sweden)
DTSTART:20210610T150000Z
DTEND:20210610T161500Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/49
DESCRIPTION:Title: Finite element analysis of an inverse problem for Maxwell's equations
with application to microwave thermometry\nby Larisa Beilina (Chalmers
\, Sweden) as part of Control in Times of Crisis. Online seminar.\n\nAbstr
act: TBA\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/49/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Stephen Guffey (U. Memphis\, US)
DTSTART:20210603T150000Z
DTEND:20210603T153000Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/50
DESCRIPTION:Title: Local Null Controllability for a Chemotactic Model for Bacterial Infec
tion in a Chronic Wound\nby Stephen Guffey (U. Memphis\, US) as part o
f Control in Times of Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/50/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jehan Alswaihli
DTSTART:20210603T153000Z
DTEND:20210603T160000Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/51
DESCRIPTION:Title: Iteration of inverse problems and data assimilation techniques for neu
ral field equations.\nby Jehan Alswaihli as part of Control in Times o
f Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/51/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Frédéric Marbach (U Rennes\, France)
DTSTART:20210624T150000Z
DTEND:20210624T161500Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/52
DESCRIPTION:Title: Expansion for nonlinear systems\, error estimates and convergence issu
es\nby Frédéric Marbach (U Rennes\, France) as part of Control in Ti
mes of Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/52/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Franck Boyer (U Toulouse\, France)
DTSTART:20210708T150000Z
DTEND:20210708T161500Z
DTSTAMP:20260422T225754Z
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://researchseminars.org/talk/CTCSeminar/53/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hugo Parada
DTSTART:20210617T150000Z
DTEND:20210617T153000Z
DTSTAMP:20260422T225754Z
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 Cont
rol in Times of Crisis. Online seminar.\n\n\nAbstract\nIn this talk we dea
l with the global well-posedness and stability of the nonlinear and linear
Korteweg-de Vries (KdV) equation on a finite star-shaped network by actin
g with saturated controls. We obtain the global well-posedness by using th
e a Sharp Kato smoothing property for the linear case and then using somes
estimates and a fixed point argument we deal with the nonlinear system. F
inally we obtain the semi-global exponential stability of two different ki
nds of saturation using a contradiction argument to prove appropriated obs
ervability inequalities.\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/54/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Luca Saluzzi (GSSI\, Italy)
DTSTART:20210617T153000Z
DTEND:20210617T160000Z
DTSTAMP:20260422T225754Z
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://researchseminars.org/talk/CTCSeminar/55/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jose Henrique Rodrigues (U. Memphis\, USA)
DTSTART:20210701T150000Z
DTEND:20210701T153000Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/56
DESCRIPTION:Title: On the well-posedness and stabilization of a nonlinear structural-acou
stic interaction problem\nby Jose Henrique Rodrigues (U. Memphis\, USA
) as part of Control in Times of Crisis. Online seminar.\n\nAbstract: TBA\
n
LOCATION:https://researchseminars.org/talk/CTCSeminar/56/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christian Montoya (U. of Dubrovnik\, Croatia)
DTSTART:20210701T153000Z
DTEND:20210701T160000Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/57
DESCRIPTION:Title: Robust Stackelberg controllability for the Kuramoto-Sivashinsky equati
on\nby Christian Montoya (U. of Dubrovnik\, Croatia) as part of Contro
l in Times of Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/57/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Rodrigo Lecaros (UTFSM\, Chile)
DTSTART:20210715T150000Z
DTEND:20210715T153000Z
DTSTAMP:20260422T225754Z
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://researchseminars.org/talk/CTCSeminar/58/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Andrew Wallon Green (Washington U\, St Louis\, USA)
DTSTART:20210715T153000Z
DTEND:20210715T160000Z
DTSTAMP:20260422T225754Z
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://researchseminars.org/talk/CTCSeminar/59/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mikko Salo (U Jyväskylä\, Finland)
DTSTART:20211007T150000Z
DTEND:20211007T161500Z
DTSTAMP:20260422T225754Z
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://researchseminars.org/talk/CTCSeminar/60/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mariano Mateos (U. de Oviedo\, Spain)
DTSTART:20211209T160000Z
DTEND:20211209T171500Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/61
DESCRIPTION:Title: Optimal control problems with non-smooth integral constraints in space
.\nby Mariano Mateos (U. de Oviedo\, Spain) as part of Control in Time
s of Crisis. Online seminar.\n\n\nAbstract\nSparsity is often a desirable
property for the solution of least squares problems that may appear\, for
instance\, in image processing or optimal control problems. Two possible t
echniques to obtain sparse solutions are the following: we can either pena
lize the functional with an $L^1$-type term or impose an upper bound on th
e norm of the control variable in $L^1$. There are several examples in the
literature about optimal control problems where the usual Tikhonov-regula
rized tracking type cost functional is penalized\, by instance\, with the
norm of the control variable in $L^1(\\Omega)$ --for problems governed by
elliptic equations-- or in $L^2(0\,T\;L^1(\\Omega))$ --in the case of prob
lems governed by parabolic equations--. In this talk\, we discuss the seco
nd technique: we impose an upper bound on the norm of the control variable
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 parabol
ic equations--. Notice that this is a quite natural condition: the ``amoun
t of control'' that you can feed into the system at each instant of time i
s usually limited by technological or economic reasons. On the other hand\
, the lack of differentiability of the constraint leads to special difficu
lties in the analysis of the problem that require new techniques of proof.
We first prove existence of solution\, and obtain necessary first order o
ptimality conditions\, from which we deduce the sparsity properties of loc
al solutions. Second order necessary and sufficient optimality conditions
with a minimal gap are also obtained. In the second part of the talk\, we
show the correct way to discretize the problem\, so that the discrete solu
tions still satisfy the sparsity properties\, prove convergence and obtain
error estimates. Finally\, we discuss optimization methods and present se
veral examples. In order to avoid some of the most technical details\, we
will focus on a problem governed by a semilinear elliptic equation\, and w
ill comment on the differences and extra difficulties that appear when the
governing equation is parabolic. This presentation is based on a collabor
ation with E. Casas (U. de Cantabria\, Spain) and K. Kunisch (U. Graz\, Au
stria).\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/61/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Emilia Fridman (Tel-Aviv University)
DTSTART:20220113T160000Z
DTEND:20220113T171500Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/62
DESCRIPTION:Title: Finite-dimensional observer-based control of parabolic PDEs\nby Em
ilia Fridman (Tel-Aviv University) as part of Control in Times of Crisis.
Online seminar.\n\n\nAbstract\nFinite-dimensional observer-based controlle
r design for PDEs is a challenging problem. In this talk\, construction of
such controllers via modal decomposition method for parabolic $1D$ PDEs w
ill be presented. We will start with a linear heat equation\, where at lea
st one of the control or observation operators is bounded. We will proceed
with the case of both unbounded operators\, where dynamic extension is he
lpful. Here the results for Kuramoto-Sivashinskii and heat equations will
be discussed. For both equations we use eigenvalues and eigenfunctions of
a Sturm-Liouville operator. The controller design is based on $N_0$ unstab
le modes\, whereas the observer dimension $N$ is not smaller than $N_0$. W
e suggest a direct Lyapunov approach to the closed-loop system\, which res
ults in an LMI whose elements depend on $N$. The value of $N$ and the deca
y rate are obtained from the LMI. We prove that the LMIs are always feasib
le for large enough $N$. Delayed and sampled-data implementations of the c
ontrollers and extensions to semilinear PDEs will be discussed. This is jo
int work with my PhD student Rami Katz.\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/62/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Pierre Lissy (U. Paris Dauphine\, France)
DTSTART:20211118T160000Z
DTEND:20211118T171500Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/63
DESCRIPTION:Title: Insensitizing controls for the heat equation with respect to boundary
variations\nby Pierre Lissy (U. Paris Dauphine\, France) as part of Co
ntrol in Times of Crisis. Online seminar.\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/63/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Otared Kavian (U. Versailles\, France)
DTSTART:20220303T160000Z
DTEND:20220303T171500Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/64
DESCRIPTION:Title: Remarks on the Cauchy problem for the Laplacian and the Approximate La
grangian controllability of the Euler Equation\nby Otared Kavian (U. V
ersailles\, France) as part of Control in Times of Crisis. Online seminar.
\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/64/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jérôme Le Rousseau (U. Sorbonne Paris Nord\, France)
DTSTART:20220407T150000Z
DTEND:20220407T161500Z
DTSTAMP:20260422T225754Z
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://researchseminars.org/talk/CTCSeminar/65/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ana Leonor Silvestre (Universidade de Lisboa)
DTSTART:20220210T160000Z
DTEND:20220210T171500Z
DTSTAMP:20260422T225754Z
UID:CTCSeminar/66
DESCRIPTION:Title: Optimal boundary control for drag minimization in a fluid-rigid body i
nteraction\nby Ana Leonor Silvestre (Universidade de Lisboa) as part o
f Control in Times of Crisis. Online seminar.\n\n\nAbstract\nConsider a ri
gid body ${\\mathcal S} \\subset {\\mathbb R}^3$ immersed in a Navier-Stok
es liquid and the motion of the body-fluid interaction system described fr
om 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 $\\Omega = {\\mathbb R}^3 \\setminus {\\mathc
al S}$. \nWe are interested in the following problem: how to use boundary
controls\, acting on the whole $\\partial\\Omega$ or just on a portion $\\
Gamma$ of $\\partial\\Omega$\, to generate a self-propelled motion of ${\\
mathcal S}$ with a target velocity $V(x):=\\xi+\\omega \\times x$ and mini
mize the drag about ${\\mathcal S}$.\nThis is joint work with Toshiaki His
hida (Nagoya University\, Japan) and Tak\\'eo Takahashi (INRIA Nancy-Grand
Est\, France).\n
LOCATION:https://researchseminars.org/talk/CTCSeminar/66/
END:VEVENT
END:VCALENDAR