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Wyszukujesz frazę "optimal method" wg kryterium: Temat


Wyświetlanie 1-10 z 10
Tytuł:
Shape optimization for stationary Navier-Stokes equations
Autorzy:
Halanay, A.
Tiba, D.
Powiązania:
https://bibliotekanauki.pl/articles/970751.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
optimal design
optimal control method
fluid mechanics
penalization
gradient method
Opis:
This work discusses geometric optimization problems governed by stationary Navier-Stokes equations. Optimal domains are proved to exist under the assumption that the family of admissible domains is bounded and satisfies the Lipschitz condition with a uniform constant, and in the absence of the uniqueness property for the state system. Through the parametrization of the admissible shapes by continuous functions defined on a larger universal domain, the optimization parameter becomes a control, i.e. an element of that family of continuous functions. The approximating extension technique via the penalization of the Navier-Stokes equation enables the approximation of the associated shape optimization problem by an optimal control problem. Results on existence and uniqueness are proved for the approximating problem and a gradient-type algorithm is indicated.
Źródło:
Control and Cybernetics; 2009, 38, 4B; 1359-1374
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Metric regularity under approximations
Autorzy:
Dontchev, A. L.
Veliov, V. M.
Powiązania:
https://bibliotekanauki.pl/articles/970750.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
metric regularity
inexact iterative methods
Newton method
proximal point method
discrete approximation
optimal control
Opis:
In this paper we show that metric regularity and strong metric regularity of a set-valued mapping imply convergence of inexact iterative methods for solving a generalized equation associated with this mapping. To accomplish this, we first focus on the question how these properties are preserved under changes of the mapping and the reference point. As an application, we consider discrete approximations in optimal control.
Źródło:
Control and Cybernetics; 2009, 38, 4B; 1283-1303
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Approximate relaxed descent method for optimal control problems
Autorzy:
Chryssoverghi, I.
Coletsos, J.
Kokkinis, B.
Powiązania:
https://bibliotekanauki.pl/articles/206679.pdf
Data publikacji:
2001
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
dyskretyzacja
kontrola relaksacyjna
sterowanie optymalne
descent method
discretization
optimal control
relaxed controls
Opis:
We consider an optimal control problem for systems governed by ordinary differential equations with control constraints. Since no convexity assumptions are made on the data, the problem is reformulated in relaxed form. The relaxed state equation is discretized by the implicit trapezoidal scheme and the relaxed controls are approximated by piecewise constant relaxed controls. We then propose a combined descent and discretization method that generates sequences of discrete relaxed controls and progressively refines the discretization. Since here the adjoint of the discrete state equation is not defined, we use, at each iteration, an approximate derivative of the cost functional defined by discretizing the continuous adjoint equation and the integral involved by appropriate trapezoidal schemes. It is proved that accumulation points of sequences constructed by this method satisfy the strong relaxed necessary conditions for optimality for the continuous problem. Finally, the computed relaxed controls can be easily approximated by piecewise constant classical controls.
Źródło:
Control and Cybernetics; 2001, 30, 4; 385-404
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimal stopping model with unknown transition probabilities
Autorzy:
Horiguchi, M.
Piunovskiy, A. B.
Powiązania:
https://bibliotekanauki.pl/articles/205727.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
Markov Decision Process (MDP) unknown transition matrices
dynamic programming
Bayesian method
optimal stopping
Opis:
This article concerns the optimal stopping problem for a discrete-time Markov chain with observable states, but with unknown transition probabilities. A stopping policy is graded via the expected total-cost criterion resulting from the non-negative running and terminal costs. The Dynamic Programming method, combined with the Bayesian approach, is developed. A series of explicitly solved meaningful examples illustrates all the theoretical issues.
Źródło:
Control and Cybernetics; 2013, 42, 3; 593-612
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Approximation of optimal control problems with bound constraints by control parameterization
Autorzy:
Alt, W.
Powiązania:
https://bibliotekanauki.pl/articles/970516.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
sterowanie optymalne nieliniowe
metoda Newtona
nonlinear optimal control
bound constraints
Newton's method
control parameterization
Opis:
We consider nonlinear optimal control problems with bound constraints for the controls. Under the assumption that the optimal control is continuous and has finitely many smooth boundary arcs, we show that the system of optimahty conditions can be reduced to a system of operator equations. Based on this system we investigate convergence of approximations by control parameterization.
Źródło:
Control and Cybernetics; 2003, 32, 3; 451-472
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of the Lagrange-SQP-Newton method for the control of a phase field equation
Autorzy:
Heinkenschloss, M.
Troeltzsch, F.
Powiązania:
https://bibliotekanauki.pl/articles/206519.pdf
Data publikacji:
1999
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
równania paraboliczne
równania różniczkowe
stabilność
sterowanie optymalne
control constraints
Lagrange-SQP-Newton method
optimal control
phase field equation
programming method
sequential quadratic
Opis:
This paper investigates the local convergence of the Lagrange-SQP-Newton method applied to an optimal control problem governed by a phase field equation with distributed control. The phase field equation is a system of two semilinear parabolic differential equations. Stability analysis of optimization problems and regularity results for parabolic differential equations are used to proof convergence of the controls with respect to the L[sup 2](Q) norm and with respect to the L[sup infinity](Q) norm.
Źródło:
Control and Cybernetics; 1999, 28, 2; 177-211
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Approximate gradient projection method with general Runge-Kutta schemes and piecewise polynomial controls for optimal control problems
Autorzy:
Chryssoverghi, I.
Powiązania:
https://bibliotekanauki.pl/articles/970094.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
dyskretyzacja
sterowanie optymalne
optimal control
gradient projection method
discretization
non-matching Runge-Kutta schemes
piecewise polynomial controls
Opis:
This paper addresses the numerical solution of optimal control problems for systems described by ordinary differential equations with control constraints. The state equation is discretized by a general explicit Runge-Kutta scheme and the controls are approximated by functions that are piecewise polynomial, but not necessarily continuous. We then propose an approximate gradient projection method that constructs sequences of discrete controls and progressively refines the discretization. Instead of using the exact discrete cost derivative, which usually requires tedious calculations, we use here an approximate derivative of the cost functional denned by discretizing the continuous adjoint equation by the same Runge-Kutta scheme backward and the integral involved by a Newton-Cotes integration rule, both involving maximal order intermediate approximations. The main result is that strong accumulation points in L2, if they exist, of sequences generated by this method satisfy the weak necessary conditions for optimality for the continuous problem. In the unconstrained case and under additional assumptions, we prove strong convergence in L2 and derive an a posteriori error estimate. Finally, numerical examples are given.
Źródło:
Control and Cybernetics; 2005, 34, 2; 425-451
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Nash equilibrium approach for multiobjective optimal control problems with elliptic partial differential equations
Autorzy:
Dreves, A.
Powiązania:
https://bibliotekanauki.pl/articles/206122.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
multiobjective optimization
generalized Nash equilibrium
optimal control problem
elliptic partial differential equation
finite elements
interior point method
Opis:
We consider the generalized Nash equilibrium as a solution concept for multiobjective optimal control problems governed by elliptic partial differential equations with constraints not only for the control but also for the state variables. In the first part, we present a constructive proof of the existence of a generalized Nash equilibrium via an approximating sequence of suitable finite dimensional discretizations. In the second part, we propose a variant of a potential reduction algorithm for the numerical solution of these discretized problems. In contrast to the existing numerical approaches ours does not require the computation of the control–to–state mapping. Instead we introduce different state variables and guarantee that they become equal at a solution. We prove sufficient conditions for the convergence of our algorithm to a solution. Furthermore, some numerical results showing the applicability are provided.
Źródło:
Control and Cybernetics; 2016, 45, 4; 457-482
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Discrete relaxed method for semilinear parabolic optimal control problem
Autorzy:
Chryssoverghi, I.
Coletsos, J.
Kokkinis, B.
Powiązania:
https://bibliotekanauki.pl/articles/205973.pdf
Data publikacji:
1999
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
sterowanie optymalne
accumulation points
discrete optimisation method
discretization
distributed control
minimum principle
optimal control
parabolic equations
partial differential equations
penalty method
relaxed control
semilinear parabolic system
Opis:
We consider an optimal control problem for systems governed by semilinear parabolic partial differential equations with control and state constraints, without any convexity assumptions. A discrete optimization method is proposed to solve this problem in its relaxed form which combines a penalized Armijo type method with a finite element discretization and constructs sequences of discrete Gamkrelidze relaxed controls. Under appropriate assumptions, we prove that accumulation points of these sequences satisfy the relaxed Pontryagin necessary conditions for optimality. Moreover, we show that the Gamkrelidze controls thus generated can be replaced by simulating piecewise constant classical controls.
Źródło:
Control and Cybernetics; 1999, 28, 2; 157-176
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Boundary optimal control problem for the phase-field transition system using fractional steps method
Zadanie sterowania optymalnego brzegiem dla układu pola ze zmianą fazy z wykorzystaniem metody kroków ułamkowych
Autorzy:
Moroşanu, C.
Powiązania:
https://bibliotekanauki.pl/articles/206721.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
zagadnienie ze swobodnym brzegiem
sterowanie optymalne
metoda kroków ułamkowych
warunki optymalności
metoda elementu skończonego
metoda gradientowa
układ ze zmianą fazy
phase-field transition system
free boundary problem
optimal control
fractional steps method
optimality conditions
finite element method
gradient method
Opis:
In this paper we prove the convergence of an iterative scheme of fractional steps type for boundary optimal control problem which is governed by the phase-field transition system. The existence of an optimal control and necessary optimality conditions are given for approximating problem. A gradient type algorithm and numerical implementation of this algorithm are discussed.
W artykule dowodzi się zbieżności procedury iteracyjnej typu kroków ułamkowych dla zagadnienia sterowania optymalnego brzegiem w układzie pola ze zmianą fazy. Wykazano istnienie sterowania optymalnego i podano warunki konieczne optymalności dla zagadnienia aproksymującego. Rozpatrzono odpowiedni algorytm gradientowy oraz realizację numeryczną tego algorytmu.
Źródło:
Control and Cybernetics; 2003, 32, 1; 5-32
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-10 z 10

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