Approximate controllability and its well-posedness for the semilinear reaction-diffusion equation with internal lumped controls
The well-posedness of a swimming model in the 3-D incompressible fluid governed by the nonstationary Stokes equation
We introduce and investigate the well-posedness of a model describing the self-propelled motion of a small abstract swimmer in the 3-D incompressible fluid governed by the nonstationary Stokes equation, typically associated with low Reynolds numbers. It is assumed that the swimmer's body consists of finitely many subsequently connected parts, identified with the fluid they occupy, linked by rotational and elastic Hooke forces. Models like this are of interest in biological and engineering applications...
Addendum to "The well-posedness of a swimming model in the 3-D incompressible fluid governed by the nonstationary Stokes equation"
In this addendum we address some unintentional omission in the description of the swimming model in our recent paper (Khapalov, 2013).
Source localization and sensor placement in environmental monitoring
In this paper we discuss two closely related problems arising in environmental monitoring. The first is the source localization problem linked to the question How can one find an unknown "contamination source"? The second is an associated sensor placement problem: Where should we place sensors that are capable of providing the necessary "adequate data" for that? Our approach is based on some concepts and ideas developed in mathematical control theory of partial differential equations.
Approximate controllability and its well-posedness for the semilinear reaction-diffusion equation with internal lumped controls
We consider the one dimensional semilinear reaction-diffusion equation, governed in Ω = (0,1) by controls, supported on any subinterval of , which are the functions of time only. Using an asymptotic approach that we have previously introduced in [9], we show that such a system is approximately controllable at any time in both (0,1)( and [0,1], provided the nonlinear term grows at infinity no faster than certain power of . The latter depends on the regularity...
Global non-negative controllability of the semilinear parabolic equation governed by bilinear control
We study the global approximate controllability of the one dimensional semilinear convection-diffusion-reaction equation governed in a bounded domain via the coefficient (bilinear control) in the additive reaction term. Clearly, even in the linear case, due to the maximum principle, such system is not globally or locally controllable in any reasonable linear space. It is also well known that for the superlinear terms admitting a power growth at infinity the global approximate controllability by...
Global non-negative controllability of the semilinear parabolic equation governed by bilinear control
We study the global approximate controllability of the one dimensional semilinear convection-diffusion-reaction equation governed in a bounded domain the coefficient () in the additive reaction term. Clearly, even in the linear case, due to the maximum principle, such system is not globally or locally controllable in any reasonable linear space. It is also well known that for the superlinear terms admitting a power growth at infinity the global approximate controllability by traditional additive...
Reachability of nonnegative equilibrium states for the semilinear vibrating string by varying its axial load and the gain of damping
We show that the set of nonnegative equilibrium-like states, namely, like of the semilinear vibrating string that can be reached from any non-zero initial state , by varying its axial load and the gain of damping, is dense in the “nonnegative” part of the subspace of . Our main results deal with nonlinear terms which admit at most the linear growth at infinity in and satisfy certain restriction on their total impact on (0,∞) with respect to the time-variable.
Controllability properties for the one-dimensional Heat equation under multiplicative or nonnegative additive controls with local mobile support
We discuss several new results on nonnegative approximate controllability for the one-dimensional Heat equation governed by either multiplicative or nonnegative additive control, acting within a proper subset of the space domain at every moment of time. Our methods allow us to link these two types of controls to some extend. The main results include approximate controllability properties both for the static and mobile control supports.
Energy decay estimates for Lienard's equation with quadratic viscous feedback.
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