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Atmospheric flow equations govern the time evolution of chemical concentrations in the
atmosphere. When considering gas and particle phases, the underlying partial differential
equations involve advection and diffusion operators, coagulation effects, and evaporation
and condensation phenomena between the aerosol particles and the gas phase. Operator
splitting techniques are generally used in global air quality models. When considering
organic aerosol...
The paper deals with approximations and the numerical realization of a class of hemivariational inequalities used for modeling of delamination and nonmonotone friction problems. Assumptions guaranteeing convergence of discrete models are verified and numerical results of several model examples computed by a nonsmooth variant of Newton method are presented.
In this article, a technique called Meta-Optimization is used to enhance the effectiveness of bio-inspired algorithms that solve antenna array synthesis problems. This technique consists on a second optimization layer that finds the best behavioral parameters for a given algorithm, which allows to achieve better results. Bio-inspired computational methods are useful to solve complex multidimensional problems such as the design of antenna arrays. However, their performance depends heavily on the...
In this work, the least pointwise upper and/or lower bounds on the state variable on a specified subdomain of a control system under piecewise constant control action are sought. This results in a non-smooth optimization problem in function spaces. Introducing a Moreau-Yosida regularization of the state constraints, the problem can be solved using a superlinearly convergent semi-smooth Newton method. Optimality conditions are derived, convergence of the Moreau-Yosida regularization is proved, and...
In this work, the least pointwise upper and/or lower bounds on the state variable
on a specified subdomain of a control system under piecewise constant control action are sought.
This results in a non-smooth optimization problem in function spaces. Introducing a Moreau-Yosida
regularization of the state constraints, the problem can be solved
using a superlinearly convergent semi-smooth Newton method.
Optimality conditions are derived, convergence of the Moreau-Yosida
regularization is proved, and...
In this paper we consider the numerical computation of the optimal cost
function associated to the problem that consists in finding the minimum of
the maximum of a scalar functional on a trajectory. We present an
approximation method for the numerical solution which employs both
discretization on time and on spatial variables. In this way, we obtain a
fully discrete problem that has unique solution. We give an optimal estimate
for the error between the approximated solution and the optimal cost
function...
The approximation of a mixed formulation of elliptic variational inequalities is studied. Mixed formulation is defined as the problem of finding a saddle-point of a properly chosen Lagrangian on a certain convex set . Sufficient conditions, guaranteeing the convergence of approximate solutions are studied. Abstract results are applied to concrete examples.
A general setting is proposed for the mixed finite element approximations of elliptic differential problems involving a unilateral boundary condition. The treatment covers the Signorini problem as well as the unilateral contact problem with or without friction. Existence, uniqueness for both the continuous and the discrete problem as well as error estimates are established in a general framework. As an application, the approximation of the Signorini problem by the lowest order mixed finite element...
A general setting is proposed for the mixed finite element approximations of
elliptic differential problems involving a unilateral boundary condition. The
treatment covers the Signorini problem as well as the unilateral contact
problem with or without friction. Existence, uniqueness for both the
continuous and the discrete problem as well as error estimates are established
in a general framework. As an application, the approximation of the Signorini
problem by the lowest order mixed finite element...
We propose a modification of the golden ratio algorithm for solving pseudomonotone equilibrium problems with a Lipschitz-type condition in Hilbert spaces. A new non-monotone stepsize rule is used in the method. Without such an additional condition, the theorem of weak convergence is proved. Furthermore, with strongly pseudomonotone condition, the $R$-linear convergence rate of the method is established. The results obtained are applied to a variational inequality problem, and the convergence rate...
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