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Wyszukujesz frazę "optimal method" wg kryterium: Temat


Tytuł:
A conservative scheme with optimal error estimates for a multidimensional space-fractional Gross–Pitaevskii equation
Autorzy:
Hendy, Ahmed S.
Macías-Díaz, Jorge E.
Powiązania:
https://bibliotekanauki.pl/articles/330834.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
generalized Gross–Pitaevskii system
Riesz fractional diffusion
Sobolev inequality
conservative method
optimal error bounds
równanie Grossa-Pitaevskiego
nierówność Sobolewa
metoda konserwatywna
optymalna granica błędu
Opis:
The present work departs from an extended form of the classical multi-dimensional Gross–Pitaevskii equation, which considers fractional derivatives of the Riesz type in space, a generalized potential function and angular momentum rotation. It is well known that the classical system possesses functionals which are preserved throughout time. It is easy to check that the generalized fractional model considered in this work also possesses conserved quantities, whence the development of conservative and efficient numerical schemes is pragmatically justified. Motivated by these facts, we propose a finite-difference method based on weighted-shifted Grünwald differences to approximate the solutions of the generalized Gross–Pitaevskii system. We provide here a discrete extension of the uniform Sobolev inequality to multiple dimensions, and show that the proposed method is capable of preserving discrete forms of the mass and the energy of the model. Moreover, we establish thoroughly the stability and the convergence of the technique, and provide some illustrative simulations to show that the method is capable of preserving the total mass and the total energy of the generalized system.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2019, 29, 4; 713-723
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A direct and accurate adaptive semi-Lagrangian scheme for the Vlasov-Poisson equation
Autorzy:
Campos Pinto, M.
Powiązania:
https://bibliotekanauki.pl/articles/929689.pdf
Data publikacji:
2007
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
metoda Lagrangiana
oszacowanie błędu
szybkość zbieżności
fully adaptive scheme
semi-Lagrangian method
Vlasov-Poisson equation
error estimate
convergence rates
optimal transport of adaptive multiscale meshes
Opis:
This article aims at giving a simplified presentation of a new adaptive semi-Lagrangian scheme for solving the (1 + 1)- dimensional Vlasov-Poisson system, which was developed in 2005 with Michel Mehrenberger and first described in (Campos Pinto and Mehrenberger, 2007). The main steps of the analysis are also given, which yield the first error estimate for an adaptive scheme in the context of the Vlasov equation. This article focuses on a key feature of our method, which is a new algorithm to transport multiscale meshes along a smooth flow, in a way that can be said optimal in the sense that it satisfies both accuracy and complexity estimates which are likely to lead to optimal convergence rates for the whole numerical scheme. From the regularity analysis of the numerical solution and how it gets transported by the numerical flow, it is shown that the accuracy of our scheme is monitored by a prescribed tolerance parameter \epsilon which represents the local interpolation error at each time step. As a consequence, the numerical solutions are proved to converge in L\infty towards the exact ones as \epsilon and \delta t tend to zero, and in addition to the numerical tests presented in (Campos Pinto and Mehrenberger, 2007), some complexity bounds are established which are likely to prove the optimality of the meshes.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2007, 17, 3; 351-359
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A hybrid method for the optimal reactive power dispatch and the control of voltagesin an electrical energy network
Autorzy:
Benchabira, Aissa
Khiat, Mounir
Powiązania:
https://bibliotekanauki.pl/articles/140740.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
electrical energy network
interior point method (IPM)
optimal reactive power dispatch (ORPD)
particle swarm optimization (PSO)
Opis:
This paper presents the resolution of the optimal reactive power dispatch (ORPD) problem and the control of voltages in an electrical energy system by using a hybrid algorithm based on the particle swarmoptimization (PSO) method and interior point method (IPM). The IPM is based on the logarithmic barrier (LB-IPM) technique while respecting the non-linear equality and inequality constraints. The particle swarmoptimization-logarithmic barrier-interior point method (PSO-LB-IPM) is used to adjust the control variables, namely the reactive powers, the generator voltages and the load controllers of the transformers, in order to ensure convergence towards a better solution with the probability of reaching the global optimum. The proposed method was first tested and validated on a two-variable mathematical function using MATLAB as a calculation and execution tool, and then it is applied to the ORPD problem to minimize the total active losses in an electrical energy network. To validate the method a testwas carried out on the IEEE electrical energy network of 57 buses.
Źródło:
Archives of Electrical Engineering; 2019, 68, 3; 535-551
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
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:
A Nearly Optimal Fractional Delay Filter Design Using an Asymmetric Window
Autorzy:
Sac, M.
Blok, M.
Powiązania:
https://bibliotekanauki.pl/articles/227063.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
asymmetric window
extracted window
fractional delay filter
nearly optimal filter
window method
Opis:
In this paper a numerically efficient filter design method suitable for variable fractional delay (VFD) filter implementation is investigated. We propose to use a well known window method with an asymmetric window extracted from optimal filter designed beforehand. As we will demonstrate, such an approach, if additional gain correction is applied, allows for nearly optimal VFD filter design. Thus, the proposed approach combines window method simplicity with performance comparable to that of optimal filters. Efficiency of the presented technique makes it suitable for designing filters with varying delay in real time
Źródło:
International Journal of Electronics and Telecommunications; 2011, 57, 4; 465-472
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A quadratic optimal control problem for a class of linear discrete distributed systems
Autorzy:
Rachik, M.
Lhous, M.
El Kahlaoui, O.
Labriji, E.
Jourhmane, H.
Powiązania:
https://bibliotekanauki.pl/articles/908382.pdf
Data publikacji:
2006
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
system dyskretny
rozproszony system komputerowy
system liniowy
sterowanie optymalne
discrete distributed system
Hilbert uniqueness method
linear system
optimal control
Opis:
A linear quadratic optimal control problem for a class of discrete distributed systems is analyzed. To solve this problem, we introduce an adequate topology and establish that optimal control can be determined though an inversion of the appropriate isomorphism. An example and a numerical approach are given.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2006, 16, 4; 431-440
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A sufficient condition for existence of constantly nondominated trajectories in linear time-invariant systems
Warunek wystarczający istnienia stale niezdominowanej trajektorii w liniowym stacjonarnym systemie dynamicznym
Autorzy:
Domka, M.
Powiązania:
https://bibliotekanauki.pl/articles/282140.pdf
Data publikacji:
2018
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
multi-criteria optimal control
attainable set
reachable set
supporting hyperplane method
wielokryterialne sterowania optymalne
zbiór osiągalny
metoda hiperpłaszczyzn podpierających
Opis:
This paper considers the multi-criteria optimal control problem in linear time-invariant systems with a single bounded input. It has been proven that, under certain assumptions, a state trajectory is non-dominated throughout the whole control process if and only if it is yielded by a control signal that belongs to a particular class of bang-bang functions. Furthermore, an explicit formula relating hyperplanes tangent to an attainable set and control switching times is presented.
W artykule rozważono problem wielokryterialnego sterowania optymalnego w liniowym stacjonarnym systemie dynamicznym z jednym wejściem przyjmującym wartości z ograniczonego przedziału. W szczególności udowodniono, że przy spełnieniu określonych założeń trajektoria stanu jest niezdominowana w trakcie całego procesu sterowania wtedy i tylko wtedy, gdy jest generowana przez sterowanie należące do pewnej klasy sygnałów typu bang-bang. Ponadto został przedstawiony wzór pozwalający wyrazić hiperpłaszczyznę styczną do zbioru osiągalnego w funkcji czasów przełączeń sygnału sterującego.
Źródło:
Automatyka / Automatics; 2018, 22, 1; 7-22
1429-3447
2353-0952
Pojawia się w:
Automatyka / Automatics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An optimal shape design problem for a hyperbolic hemivariational inequality
Autorzy:
Gasiński, Leszek
Powiązania:
https://bibliotekanauki.pl/articles/729253.pdf
Data publikacji:
2000
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
optimal shape design
mapping method
hemivariational inequalities
Clarke subdifferential
Opis:
In this paper we consider hemivariational inequalities of hyperbolic type. The existence result for hemivariational inequality is given and the existence theorem for the optimal shape design problem is shown.
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2000, 20, 1; 41-50
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
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:
Analytical solution for magnetohydrodynamic stagnation point flow and heat transfer over a permeable stretching sheet with chemical reaction
Autorzy:
Rasekh, A.
Farzaneh-Gord, M.
Varedi, S. R.
Ganji, D. D.
Powiązania:
https://bibliotekanauki.pl/articles/279659.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
MHD stagnation point flow
permeable stretching sheet
heat and mass transfer
Optimal Homotopy Asymptotic Method (OHAM)
Opis:
This work deals with the problem of steady two-dimensional magnetohydrodynamic (MHD) stagnation point flow towards a permeable stretching sheet with chemical reaction. The fundamental equations of the boundary layer are transformed into ordinary differential equations, which are then solved analytically using the Optimal Homotopy Asymptotic Method (OHAM). Comparisons are made between the results of the proposed method and the numerical method (fourth-order Runge-Kutta) in solving this problem, and excellent agrement has been observed. Subsequently, effects of different involved parameters on the temperature profiles, concentration profiles, local Nusselt number, local Sherwood number and skin-friction coefficient are presented and discussed in detail.
Źródło:
Journal of Theoretical and Applied Mechanics; 2013, 51, 3; 675-686
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of multi-objective fruit fly optimisation algorithm based on population Manhattan distance in distribution network reconfiguration
Autorzy:
Tang, Minan
Zhang, Kaiyue
Wang, Qianqian
Cheng, Haipeng
Yang, Shangmei
Du, Hanxiao
Powiązania:
https://bibliotekanauki.pl/articles/1841286.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Chebyshev chaotic mapping
distributed generation
distribution network reconfiguration
fuzzy decision method
Pareto optimal
pmdMOFOA
population Manhattan distance
Opis:
In order to optimise the operation state of the distribution network in the presence of distributed generation (DG), to reduce network loss, balance load and improve power quality in the distribution system, a multi-objective fruit fly optimisation algorithm based on population Manhattan distance (pmdMOFOA) is presented. Firstly, the global and local exploration abilities of a fruit fly optimisation algorithm (FOA) are balanced by combining population Manhattan distance (PMD) and the dynamic step adjustment strategy to solve the problems of its weak local exploration ability and proneness to premature convergence. At the same time, Chebyshev chaotic mapping is introduced during position update of the fruit fly population to improve ability of fruit flies to escape the local optimum and avoid premature convergence. In addition, the external archive selection strategy is introduced to select the best individual in history to save in external archives according to the dominant relationship amongst individuals. The leader selection strategy, external archive update and maintenance strategy are proposed to generate a Pareto optimal solution set iteratively. Lastly, an optimal reconstruction scheme is determined by the fuzzy decision method. Compared with the standard FOA, the average convergence algebra of a pmdMOFOA is reduced by 44.58%. The distribution performance of non-dominated solutions of a pmdMOFOA, MOFOA, NSGA-III and MOPSO on the Pareto front is tested, and the results show that the pmdMOFOA has better diversity. Through the simulation and analysis of a typical IEEE 33-bus system with DG, load balance and voltage offset after reconfiguration are increased by 23.77% and 40.58%, respectively, and network loss is reduced by 57.22%, which verifies the effectiveness and efficiency of the proposed method.
Źródło:
Archives of Electrical Engineering; 2021, 70, 2; 307-323
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
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:
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:
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:
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

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