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Wyszukujesz frazę "asymptotic expansion" wg kryterium: Temat


Wyświetlanie 1-8 z 8
Tytuł:
Adaptive finite elements based on sensitivities fortopological mesh changes
Autorzy:
Friederich, J.
Leugering, G.
Steinmann, P.
Powiązania:
https://bibliotekanauki.pl/articles/205694.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
adaptive mesh refinement
sensitivity-based refinement
topological sensitivity
asymptotic expansion
Opis:
We propose a novel approach to adaptive refinement in FEM based on local sensitivities for node insertion. To this end, we consider refinement as a continuous graph operation, for instance by splitting nodes along edges. Thereby, we introduce the concept of the topological mesh derivative for a given objective function. For its calculation, we rely on the first-order asymptotic expansion of the Galerkin solution of a symmetric linear second-order elliptic PDE. In this work, we apply this concept to the total potential energy, which is related to the approximation error in the energy norm. In fact, our approach yields local sensitivities for minimization of the energy error by refinement. Moreover, we prove that our indicator is equivalent to the classical explicit a posteriori error estimator in a certain sense. Numerical results suggest that our method leads to efficient and competitive adaptive refinement.
Źródło:
Control and Cybernetics; 2014, 43, 2; 279-306
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Topological derivative for optimal control problems
Autorzy:
Sokołowski, J.
Żochowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/206790.pdf
Data publikacji:
1999
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
sterowanie optymalne
asymptotic expansion
control problems
shape derivative
shape optimization
topological derivative
Opis:
The topological derivative is introduced for the extremal values of cost functionals for control problems. The optimal control problem considered in the paper is defined for the elliptic equation which models the deflection of an elastic membrane. The derivative measures the sensitivity of the optimal value of the cost with respect to changes in topology. A change in topology means removing a small ball from the interior of the domain of integration. The topological derivative can be used for obtaining the numerical solutions of the shape optimization problems.
Źródło:
Control and Cybernetics; 1999, 28, 3; 611-625
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Shape and topology optimization of distributed parameter systems
Autorzy:
Sokołowski, J.
Żochowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/206802.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
shape optimization
topological derivative
asymptotic analysis
singularly perturbed geometrical domains
asymptotic expansion of energ functional
Opis:
The energy functional for an elliptic boundary value problem in two spatial dimensions is considered. The variations of shape functional resulting from the small shape-topological domain perturbations with the holes and inclusions in elastic body are determined. The exact representation of solutions to the boundary value problem is exploited for the purposes of asymptotic analysis. To this end the perturbed solutions of the boundary value problem are Expressem as the minimizers of perturbed energy functionals. The proposed method of asymptotic analysis results in the double asymptotic expansions, with respect to the size of a hole and to the contrast parameter of an inclusion with respect to the matrix, of solutions to the boundary value problems as well as of the associated energy functional. The shape sensitivity analysis of the energy functional with respekt of the boundary variations of an inclusion is performed. The further asymptotic analysis allows for the limit passage with the size of inclusion to zero. In this way the topological derivative of the energy functional is obtained. The proposed analysis can be used in the shape and topology optimum design for elastic bodies governed by the stationary as well as by the time dependent elasticity boundary value problems in the framework of selfadjoint extensions of elliptic operators.
Źródło:
Control and Cybernetics; 2013, 42, 1; 217-226
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Asymptotic expansions for the first hitting times of bessel processes
Autorzy:
Hamana, Yuji
Kaikura, Ryo
Shinozaki, Kosuke
Powiązania:
https://bibliotekanauki.pl/articles/2052013.pdf
Data publikacji:
2021
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
Bessel process
hitting time
tail probability
modified Bessel function
asymptotic expansion
Laplace transform
Opis:
We study a precise asymptotic behavior of the tail probability of the first hitting time of the Bessel process. We deduce the order of the third term and decide the explicit form of its coefficient.
Źródło:
Opuscula Mathematica; 2021, 41, 4; 509-537
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of a boundary perforation on the Dirichlet energy
Autorzy:
Dambrine, M.
Vial, G.
Powiązania:
https://bibliotekanauki.pl/articles/970142.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
pochodna kształtu
pochodna topologiczna
singular shape perturbation
shape derivatives
topological derivatives
multi-scale asymptotic expansion
Opis:
We consider some singular perturbations of the boundary of a smooth domain. Such domain variations are not differentiable within the classical theory of shape calculus. We mimic the topological asymptotic and we derive an asymptotic expansion of the shape function in terms of a size parameter. The two-dimensional case of the Dirichlet energy is treated in detail. We give a full theoretical proof as well as a numerical confirmation of the results.
Źródło:
Control and Cybernetics; 2005, 34, 1; 117-136
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the summability of divergent power series solutions for certain first-order linear PDES
Autorzy:
Hibino, M.
Powiązania:
https://bibliotekanauki.pl/articles/255352.pdf
Data publikacji:
2015
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
partial differential equation
divergent power series
summability
asymptotic expansion
analytic continuation
integro-differential equation
integral equation
Opis:
This article is concerned with the study of the Borel summability of divergent power series solutions for certain singular first-order linear partial differential equations of nilpotent type. Our main purpose is to obtain conditions which coefficients of equations should satisfy in order to ensure the Borel summability of divergent solutions. We will see that there is a close affinity between the Borel summability of divergent solutions and global analytic continuation properties for coefficients of equations.
Źródło:
Opuscula Mathematica; 2015, 35, 5; 595-624
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Asymptotic approximations to the non-isothermal distributed activation energy model for bio-mass pyrolysis
Autorzy:
Dhaundiyal, A.
Singh, S. B.
Powiązania:
https://bibliotekanauki.pl/articles/386522.pdf
Data publikacji:
2017
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
biomass pyrolysis
distributed activation energy model (DAEM)
DAEM
non-isothermal kinetics
gamma distribution
asymptotic expansion
erlang distribution
Opis:
This paper describes the influence of some parameters significant to biomass pyrolysis on the numerical solutions of the non-isothermal nth order distributed activation energy model (DAEM) using the Gamma distribution and discusses the special case for the positive integer value of the scale parameter (), i.e. the Erlang distribution. Investigated parameters are the integral upper limit, the frequency factor, the heating rate, the reaction order, and the shape and rate parameters of the Gamma distribution. Influence of these parameters has been considered for the determination of the kinetic parameters of the non-isothermal nth order Gamma distribution from the experimentally derived thermoanalytical data of biomass pyrolysis. Mathematically, the effect of parameters on numerical solution is also used for predicting the behaviour of the unpyrolysized fraction of biomass with respect to temperature. Analysis of the mathematical model is based upon asymptotic expansions, which leads to the systematic methods for efficient way to determine the accurate approximations. The proposed method, therefore, provides a rapid and highly effective way for estimating the kinetic parameters and the distribution of activation energies.
Źródło:
Acta Mechanica et Automatica; 2017, 11, 4; 293-301
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A robust computational technique for a system of singularly perturbed reaction–diffusion equations
Autorzy:
Kumar, V.
Bawa, R. K.
Lal, A. K.
Powiązania:
https://bibliotekanauki.pl/articles/330202.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
asymptotic expansion approximation
backward difference operator
trapezoidal method
piecewise uniform Shishkin mesh
rozwinięcie asymptotyczne
operator różnicowy
metoda trapezowa
Opis:
In this paper, a singularly perturbed system of reaction–diffusion Boundary Value Problems (BVPs) is examined. To solve such a type of problems, a Modified Initial Value Technique (MIVT) is proposed on an appropriate piecewise uniform Shishkin mesh. The MIVT is shown to be of second order convergent (up to a logarithmic factor). Numerical results are presented which are in agreement with the theoretical results.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2014, 24, 2; 387-395
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-8 z 8

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