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Papers by Irena Lasiecka
Mathematics of Computation, 1991
This paper studies a wave equation on a bounded domain in with nonlinear dissipation which is loc... more This paper studies a wave equation on a bounded domain in with nonlinear dissipation which is localized on a subset of the boundary. The damping is modeled by a continuous monotone function without the usual growth restrictions imposed at the origin and infinity. Under the assumption that the observability inequality is satisfied by the solution of the associated linear problem, the asymptotic decay rates of the energy functional are obtained by reducing the nonlinear PDE problem to a linear PDE and a nonlinear ODE. This approach offers a generalized framework which incorporates the results on energy decay that appeared previously in the literature; the method accommodates systems with variable coefficients in the principal elliptic part, and allows to dispense with linear restrictions on the growth of the dissipative feedback map.
Siam J Contr Optimizat, 1991
Appl Math Opt, 1980
Quadratic control problems for parabolic equations withstate constraints are considered. Regulari... more Quadratic control problems for parabolic equations withstate constraints are considered. Regularity (smoothness) of the optimal solution is investigated. It is shown that the optimal control is continuous in time with the values inL2(O) and its time derivative belongs toL2[OT×O].
Siam J Numer Anal, 1984
... i(A)= {fEL2(r IAfEL2(f);fIr=Oor (af-) o 0} where af/an stands for the normal derivative. It i... more ... i(A)= {fEL2(r IAfEL2(f);fIr=Oor (af-) o 0} where af/an stands for the normal derivative. It is a well-known fact that -A generates on L2(fl) a strongly continuous, analytic semigroup S(t) = eAt such that (2.1) IS (t)l C e wt. ... Page 3. 896 IRENA LASIECKA (see [P1]) ...
Annali Di Matematica Pura Ed Applicata, 1986
Nonlinear Analysis Theory Methods Applications, Feb 29, 1992
International Journal of Applied Mathematics and Computer Science, 2001
Journal of Differential Equations, 2015
Computers Mathematics With Applications, Feb 28, 1994
Http Dx Doi Org 10 1080 01630569108816443, May 15, 2007
ABSTRACT
ABSTRACT We consider the Moore-Gibson-Thompson equation which arises, e.g., as a linearization of... more ABSTRACT We consider the Moore-Gibson-Thompson equation which arises, e.g., as a linearization of a model for wave propagation in viscous thermally relaxing fluids. This third order in time equation displays, even in the linear version, a variety of dynamical behaviors for their solutions that depend on the physical parameters in the equation. These range from non-existence and instability to exponential stability (in time). By neglecting diffusivity of the sound coefficient there is a lack of generation of a semigroup associated with the linear dynamics. When diffusivity of the sound is positive, the linear dynamics is described by a strongly continuous evolution. We shall show that this evolution is exponentially stable provided sufficiently large viscous damping is accounted for in the model. The viscosity considered is time and space dependent which then leads to evolution rather then semigroup generators. Decay rates for both natural and higher level energies are derived.
Appl Math Opt, 1977
... Irena Lasiecka Department of System Science, University of California at Los Angeles, Los Ang... more ... Irena Lasiecka Department of System Science, University of California at Los Angeles, Los Angeles, California ... coefficients in 9. Since T is assumed to be strongly elliptic, then there exists a constant a >0 such that the quadratic form N X aij~i~j > ot X ~i 2 for all ¢ E fL i=l i=l ...
Siam Journal on Mathematical Analysis, Jul 17, 2006
Lecture Notes in Control and Information Sciences, 1988
Mathematics of Computation, 1991
This paper studies a wave equation on a bounded domain in with nonlinear dissipation which is loc... more This paper studies a wave equation on a bounded domain in with nonlinear dissipation which is localized on a subset of the boundary. The damping is modeled by a continuous monotone function without the usual growth restrictions imposed at the origin and infinity. Under the assumption that the observability inequality is satisfied by the solution of the associated linear problem, the asymptotic decay rates of the energy functional are obtained by reducing the nonlinear PDE problem to a linear PDE and a nonlinear ODE. This approach offers a generalized framework which incorporates the results on energy decay that appeared previously in the literature; the method accommodates systems with variable coefficients in the principal elliptic part, and allows to dispense with linear restrictions on the growth of the dissipative feedback map.
Siam J Contr Optimizat, 1991
Appl Math Opt, 1980
Quadratic control problems for parabolic equations withstate constraints are considered. Regulari... more Quadratic control problems for parabolic equations withstate constraints are considered. Regularity (smoothness) of the optimal solution is investigated. It is shown that the optimal control is continuous in time with the values inL2(O) and its time derivative belongs toL2[OT×O].
Siam J Numer Anal, 1984
... i(A)= {fEL2(r IAfEL2(f);fIr=Oor (af-) o 0} where af/an stands for the normal derivative. It i... more ... i(A)= {fEL2(r IAfEL2(f);fIr=Oor (af-) o 0} where af/an stands for the normal derivative. It is a well-known fact that -A generates on L2(fl) a strongly continuous, analytic semigroup S(t) = eAt such that (2.1) IS (t)l C e wt. ... Page 3. 896 IRENA LASIECKA (see [P1]) ...
Annali Di Matematica Pura Ed Applicata, 1986
Nonlinear Analysis Theory Methods Applications, Feb 29, 1992
International Journal of Applied Mathematics and Computer Science, 2001
Journal of Differential Equations, 2015
Computers Mathematics With Applications, Feb 28, 1994
Http Dx Doi Org 10 1080 01630569108816443, May 15, 2007
ABSTRACT
ABSTRACT We consider the Moore-Gibson-Thompson equation which arises, e.g., as a linearization of... more ABSTRACT We consider the Moore-Gibson-Thompson equation which arises, e.g., as a linearization of a model for wave propagation in viscous thermally relaxing fluids. This third order in time equation displays, even in the linear version, a variety of dynamical behaviors for their solutions that depend on the physical parameters in the equation. These range from non-existence and instability to exponential stability (in time). By neglecting diffusivity of the sound coefficient there is a lack of generation of a semigroup associated with the linear dynamics. When diffusivity of the sound is positive, the linear dynamics is described by a strongly continuous evolution. We shall show that this evolution is exponentially stable provided sufficiently large viscous damping is accounted for in the model. The viscosity considered is time and space dependent which then leads to evolution rather then semigroup generators. Decay rates for both natural and higher level energies are derived.
Appl Math Opt, 1977
... Irena Lasiecka Department of System Science, University of California at Los Angeles, Los Ang... more ... Irena Lasiecka Department of System Science, University of California at Los Angeles, Los Angeles, California ... coefficients in 9. Since T is assumed to be strongly elliptic, then there exists a constant a >0 such that the quadratic form N X aij~i~j > ot X ~i 2 for all ¢ E fL i=l i=l ...
Siam Journal on Mathematical Analysis, Jul 17, 2006
Lecture Notes in Control and Information Sciences, 1988