149 research outputs found
Convergence of optimal control problems governed by second kind parabolic variational inequalities
We consider a family of optimal control problems where the control variable
is given by a boundary condition of Neumann type. This family is governed by
parabolic variational inequalities of the second kind. We prove the strong
convergence of the optimal controls and state systems associated to this family
to a similar optimal control problem. This work solves the open problem left by
the authors in IFIP TC7 CSMO2011
Unsteady 3D-Navier-Stokes System with Tresca's Friction Law
Motivated by extrusion problems, we consider a non-stationary incompress-ible
3D fluid flow with a non-constant (temperature dependent) viscosity, subjected
to mixed boundary conditions with a given time dependent velocity on a part of
the boundary and Tresca's friction law on the other part. We construct a
sequence of approximate solutions by using a regularization of the free
boundary condition due to friction combined with a particular penalty method,
reminiscent of the " incompressibility limit " of compressible fluids, allowing
to get better insights into the links between the fluid velocity and pressure
fields. Then we pass to the limit with compactness arguments to obtain a
solution to our original problem
Existence result for a strongly coupled problem with heat convection term and Tresca's law.
International audienceWe study a problem describing the motion of an incompressible, nonisothermal and non-Newtonian uid, taking into account the heat convection term. The novelty here is that uid viscosity depends on the temperature, the velocity of the uid, and also of the deformation tensor, but not explicitly. The boundary conditions take into account the slip phenomenon on a part of the boundary of the domain. By using the notion of pseudo-monotone operators and xed point Theorem we prove an existence result of its weak solution
The Neumann problem in thin domains with very highly oscillatory boundaries
In this paper we analyze the behavior of solutions of the Neumann problem
posed in a thin domain of the type with and , defined by smooth
functions and , where the function is supposed to be
-periodic in the second variable . The condition implies
that the upper boundary of this thin domain presents a very high oscillatory
behavior. Indeed, we have that the order of its oscillations is larger than the
order of the amplitude and height of given by the small parameter
. We also consider more general and complicated geometries for thin
domains which are not given as the graph of certain smooth functions, but
rather more comb-like domains.Comment: 20 pages, 4 figure
TDAE Strategy in the Benzoxazolone Series: Synthesis and Reactivity of a New Benzoxazolinonic Anion
International audienceWe describe an original pathway to produce new 5-substituted 3-methyl-6-nitro-benzoxazolones by the reaction of aromatic carbonyl and α-carbonyl ester derivatives with a benzoxazolinonic anion formed exclusively via the TDAE strategy
A Heat Conduction Problem with Sources Depending on the Average of the Heat Flux on the Boundary
Motivated by the modeling of temperature regulation in some mediums, we
consider the non-classical heat conduction equation in the domain
D=\mathbb{R}^{n-1}\times\br^{+} for which the internal energy supply depends
on an average in the time variable of the heat flux on the boundary . The solution to the problem
is found for an integral representation depending on the heat flux on which
is an additional unknown of the considered problem. We obtain that the heat
flux must satisfy a Volterra integral equation of second kind in the time
variable with a parameter in . Under some conditions on
data, we show that a unique local solution exists, which can be extended
globally in time. Finally in the one-dimensional case, we obtain the explicit
solution by using the Laplace transform and the Adomian decomposition method.Comment: Accepted by Revista UMA, April 30 2019, in press. arXiv admin note:
substantial text overlap with arXiv:1610.0168
A Robust Approach to Characterize the Human Ear: Application to Biometric Identification
The Human ear is a new technology of biometrics which is not yet used in a real context or in commercial applications. For this purpose of biometric system, we present an improvement for ear recognition methods that use Elliptical Local Binary Pattern operator as a robust descriptor for characterizing the fine details of the two dimensional ear imaging. The improvements are focused on features extractions and dimensionalities reductions steps. The realized system is mainly appropriate for identification mode; it starts by decomposing the normalized ear image into several blocks with different resolutions. Next, the local textural descriptor is applied on each decomposed block. A problem of information redundancies is appeared due to the important size of the concatenated histograms of all blocks, which has been resolved by reducing of the histogram’s dimensionalities and by selecting the pertinent information using Haar Wavelets. Finally, the system is evaluated on the IIT Delhi Database containing two dimensional ear images and we have obtained a success rate about 97% for 493 images from 125 persons and about 96% for 793 images from 221 persons
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