Boundary null controllability of degenerate wave equation as the limit of internal controllability
Unidade Acadêmica de Matemática, Universidade Federal de Campina Grande（坎皮纳格兰德联邦大学数学学术单位）；Departamento de Ciências da Natureza, Universidade Federal Fluminense（弗鲁米嫩塞联邦大学自然科学系）；Departamento de Análise, Universidade Federal Fluminense（弗鲁米嫩塞联邦大学分析系）
Bruno S. V. Araújo, Reginaldo Demarque, Luiz Viana
This work is concerned with the possibility of proving the boundary null controllability for the degenerate wave equation, developing the asymptotic analysis of a suitable family of state-control pairs $((u_\varepsilon , v_\varepsilon))_{\varepsilon>0}$, solving related internal null controllability problems. The passage to the limit argument will be rigorously performed through the obtainment of a refined observability type inequality, with a constant explicitly given in terms of $\varepsilon >0$. This represents an essential point, since will allow us to achieve our required weak convergence results.
In this paper, we recover the boundary null controllability for the degenerate heat equation by analyzing the asymptotic behavior of an eligible family of state-control pairs $((u_{\varepsilon}, h_{\varepsilon}))_{\varepsilon >0}$ solving corresponding singularly perturbed internal null controllability problems. As in other situations studied in the literature, our approach relies on Carleman estimates and meticulous weak convergence results. However, for the degenerate parabolic case, some specific trace operator inequalities must be obtained, in order to justify correctly the passage to the …
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Existence and uniqueness of mild solutions and evolution operators for a class of non-autonomous conformable fractional semi-linear systems and Their Exact Null Controllability
We establish the null controllability for linear stochastic fourth order parabolic equations. Utilizing the duality argument, the null controllability is reduced to the observability for backward fourth order stochastic parabolic equations, and the desired observability estimate is obtained by a new global Carleman estimate. Our Carleman estimate is based on a new fundamental identity for a stochastic fourth order parabolic operator.
For a class of linear time-delay control systems satisfying the property of completability of the generalized eigenvectors we prove that the problems of complete stabilizability and exact null controllability are equivalent.
This paper is devoted to the controllability of a general linear hyperbolic system in one space dimension using boundary controls on one side. Under precise and generic assumptions on the boundary conditions on the other side, we previously established the optimal time for the null and the exact controllability for this system for a generic source term. In this work, we prove the null-controllability for any time greater than the optimal time and for any source term. Similar results for the exact controllability are also discussed.
