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Wyszukujesz frazę "regularization" wg kryterium: Wszystkie pola


Tytuł:
Regularization and discretization of linear-quadratic control problems
Autorzy:
Alt, W.
Seydenschwanz, M.
Powiązania:
https://bibliotekanauki.pl/articles/206162.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
optimal control
bang-bang control
regularization
discretization
Opis:
We analyze regularizations of a class of linear-quadratic optimal control problems with control appearing linearly. It is shown that if the optimal control is bang-bang or if a coercivity condition for the state variables is satisfied, the solutions are continuous functions of the regularization parameter. Combining error estimates for Euler discretizations of the regularized problems with those for the regularization error, we choose the regularization parameter in dependence of the meshsize to obtain optimal convergence rates for the discrete solutions. Numerical experiments confirm the theoretical findings.
Źródło:
Control and Cybernetics; 2011, 40, 4; 903-920
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A mixed integer nonlinear programming formulation for the problem of fitting positive exponential sums to empirical data
Autorzy:
Alvarez, A.
Lara, H.
Powiązania:
https://bibliotekanauki.pl/articles/254845.pdf
Data publikacji:
2011
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
mixed integer nonlinear programming
regularization
nonlinear least squares
Opis:
In this work we deal with exponential sum models coming from data acquisition in the empirical sciences. We present a two step approach based on Tikhonov regularization and combinatorial optimization, to obtain stable parameter estimations, which fit the data. We develop properties of the solutions, based on their optimality conditions. Some numerical experiments are shown to illustrate our approach.
Źródło:
Opuscula Mathematica; 2011, 31, 4; 481-499
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An inverse backward problem for degenerate two-dimensional parabolic equation
Autorzy:
Atifi, Khalid
Essoufi, El-Hassan
Khouiti, Bouchra
Powiązania:
https://bibliotekanauki.pl/articles/255085.pdf
Data publikacji:
2020
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
data assimilation
adjoint method
regularization
heat equation
inverse problem
degenerate equations
optimization
Opis:
This paper deals with the determination of an initial condition in the degenerate two-dimensional parabolic equation [formula], where Ω is an open, bounded subset of R2, a [formula] with a ≥0 everywhere, and [formula], with initial and boundary conditions [formula] from final observations. This inverse problem is formulated as a minimization problem using the output least squares approach with the Tikhonov regularization. To show the convergence of the descent method, we prove the Lipschitz continuity of the gradient of the Tikhonov functional. Also we present some numerical experiments to show the performance and stability of the proposed approach.
Źródło:
Opuscula Mathematica; 2020, 40, 4; 427-449
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimizing properties of an inertial dynamical system with geometric damping : link with proximal methods
Autorzy:
Attouch, H.
Bolte, J.
Redont, P.
Powiązania:
https://bibliotekanauki.pl/articles/205719.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
dynamical systems in optimization
entropic methods in optimization
proximal regularization method
steepest descent method
Opis:
The second-order dynamical system x + [alpha]x + Beta[...] = 0, alpha > 0, Beta > 0, where the Hessian [...]Phi(x) acts as a geometric damping, is introduced, mainly in view of the minimization of [Phi]. Minimizing [Phi] is a problem equivalent to the minimization of the functional [Psi]a,b(x, y) = 1/b^2Phi(x) + 1/2|ax + by|^2, a > 0, b > 0. The latter naturallv appears in the proximal regularization of Phi ; it may also be viewed as an energy. The continuous steepest descent method applied to [Psi]a,b yields a first-order system, which proves to he equivalent to the above-mentioned second-order system, when [Phi] is of class [C^2].
Źródło:
Control and Cybernetics; 2002, 31, 3; 643-657
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Conditional stability estimate for an ill-posed elliptic equation by using nonlocal conditions
Autorzy:
Benrabah, Abderafik
Powiązania:
https://bibliotekanauki.pl/articles/2202023.pdf
Data publikacji:
2022
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
ill-posed problem
biharmonic equation
regularization methods
nonlocal conditions
a priori estimate
problem źle postawiony
równanie biharmoniczne
metoda regularyzacji
warunki nielokalne
szacowanie a priori
Opis:
We consider an ill-posed linear homogeneous fourth-order elliptic equation. We show that the problem is ill-posed in the sense of Hadamard, i.e., the solution does not depend continuously on the given data. We propose a regularization method via nonlocal conditions and under some a priori bound assumptions different estimates for the regularized solution are obtained. Numerical examples for a rectangle domain show the effectiveness of the new method in providing highly accurate numerical solutions as the noise level tends to zero.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2022, 21, 3; 5--17
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Near fields of elliptic dielectric lenses
Autorzy:
Boriskin, A.V.
Marciniak, M.
Powiązania:
https://bibliotekanauki.pl/articles/307801.pdf
Data publikacji:
2003
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
elliptic dielectric lens
method of analytical regularization
antennas
Opis:
The focusing properties of an elliptic dielectric cylinder taken as a 2D model of dielectric lens are studied for the plane wave illumination. An algorithm based on the concept of analytical regularization is applied for the numerical solution of the corresponding wave scattering problem. Numerical results for the near-field patterns are presented.
Źródło:
Journal of Telecommunications and Information Technology; 2003, 3; 125-129
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Convolutions, integral transforms and integral equations by means of the theory of reproducing kernels
Autorzy:
Castro, L. P.
Saitoh, S.
Tuan, N. M.
Powiązania:
https://bibliotekanauki.pl/articles/256011.pdf
Data publikacji:
2012
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
Hilbert space
linear transform
reproducing kernel
linear mapping
convolution
norm inequality
integral equation
Tikhonov regularization
Opis:
This paper introduces a general concept of convolutions by means of the theory of reproducing kernels which turns out to be useful for several concrete examples and applications. Consequent properties are exposed (including, in particular, associated norm inequalities).
Źródło:
Opuscula Mathematica; 2012, 32, 4; 633-646
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On regularization in superreflexive Banach spaces by infimal convolution formulas
Autorzy:
Cepedello-Boiso, Manuel
Powiązania:
https://bibliotekanauki.pl/articles/1218460.pdf
Data publikacji:
1998
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
regularization in Banach spaces
convex functions
Opis:
We present here a new method for approximating functions defined on superreflexive Banach spaces by differentiable functions with α-Hölder derivatives (for some 0 < α≤ 1). The smooth approximation is given by means of an explicit formula enjoying good properties from the minimization point of view. For instance, for any function f which is bounded below and uniformly continuous on bounded sets this formula gives a sequence of Δ-convex $C^{1,α}$ functions converging to f uniformly on bounded sets and preserving the infimum and the set of minimizers of f. The techniques we develop are based on the use of extended inf-convolution formulas and convexity properties such as the preservation of smoothness for the convex envelope of certain differentiable functions.
Źródło:
Studia Mathematica; 1998, 129, 3; 265-284
0039-3223
Pojawia się w:
Studia Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On solvability of boundary value problems in elastoplasticity
Autorzy:
Chludnev, A.
Sokołowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/205983.pdf
Data publikacji:
1998
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
elastoplastyczność
pękanie
zagadnienie brzegowe
boundary problem
cracks
elastoplasticity
penalty
regularization
Opis:
In the paper the existence of a solution to the thress-dimensional elastoplastic problem with the Prandtl-Reuss constitutive law and the Neumann boundary conditions is established. The proof is based on a suitable combination of the parabolic regularization of equations and the penalty method for the elastoplastic yield condition. The method is applied in the case of the domain with smooth boundary as well as in the case of an interior crack. It is shown that the weak solutions to the elastoplastic problem satisfying the variational inequality meet all boundary conditions.
Źródło:
Control and Cybernetics; 1998, 27, 2; 311-330
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Uniformly continuous composition operators in the space of bounded Φ-variation functions in the Schramm sense
Autorzy:
Ereu, T.
Merentes, N.
Sanchez, J. L.
Wróbel, M.
Powiązania:
https://bibliotekanauki.pl/articles/255979.pdf
Data publikacji:
2012
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
Phi-variation in the sense of Schramm
uniformly continuous operator
regularization
composition operator
Jensen equation
locally defined operators
Opis:
We prove that any uniformly continuous Nemytskii composition operator in the space of functions of bounded generalized Φ-variation in the Schramm sense is affine. A composition operator is locally defined. We show that every locally defined operator mapping the space of continuous functions of bounded (in the sense of Jordan) variation into the space of continous monotonic functions is constant.
Źródło:
Opuscula Mathematica; 2012, 32, 2; 239-247
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Identification of nominal release policies implemented in a multi-purpose water reservoir
Autorzy:
Fadhil, Rasha M.
Unami, Koichi
Rowshon, Md Kamal
Fikri, Ahmad
Aimrun, Wayayok
Powiązania:
https://bibliotekanauki.pl/articles/2142341.pdf
Data publikacji:
2022
Wydawca:
Instytut Meteorologii i Gospodarki Wodnej - Państwowy Instytut Badawczy
Tematy:
reservoir operation
policy identification
generalized additive model
total variation regularization
Bukit Merah Reservoir
Opis:
A water reservoir’s operation should follow a rational policy to ensure adequate water provision for different purposes without adverse effects. However, it is not well-studied how to identify operational policies currently being implemented. This study establishes a new approach to identifying nominal release policies as implemented in a multi-purpose water reservoir. We chose Bukit Merah Reservoir (BMR), located in Perak State, Malaysia, as a study site to examine its release policies for meeting irrigation, municipal, and industrial water demands and for mitigating floods and environmental hazards. The operator of BMR releases the reservoir’s water into two primary irrigation canals, the Main Canal and the Selinsing Canal. Generalized additive models (GAMs) are applied to time series data observed at BMR to identify the annual dynamics of its water management. Operational policies for the release discharges into the two primary irrigation canals are assumed to be based on information on the time-of-year and the reservoir water level. First, a backfitting algorithm identifies each contributing function of the GAMs representing the release policies. Then, spurious oscillations in the functions are removed by total variation (TV) regularization (TVR) to obtain nominal release policies, which are quite reasonable in the sense of conventional reservoir management practice. Finally, the identified nominal release policies are utilized to examine shifts in the operation of BMR during the period from 2000 through 2011. The decomposition of release policies illustrates the two aspects of the irrigation demand’s annual patterns and the hydraulic structures’ functions. The spurious oscillations removed by TVR are considered to represent indecision by the reservoir operator.
Źródło:
Meteorology Hydrology and Water Management. Research and Operational Applications; 2022, 10, 2; 1--18
2299-3835
2353-5652
Pojawia się w:
Meteorology Hydrology and Water Management. Research and Operational Applications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some remarks on best regularization
Autorzy:
Friedrich, V.
Powiązania:
https://bibliotekanauki.pl/articles/720916.pdf
Data publikacji:
1984
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Źródło:
Banach Center Publications; 1984, 13, 1; 719-724
0137-6934
Pojawia się w:
Banach Center Publications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tikhonov regularization and constrained quadratic programming for magnetic coil design problems
Autorzy:
Garda, B.
Galias, Z.
Powiązania:
https://bibliotekanauki.pl/articles/330150.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
coil design problem
constrained quadratic programming
Tikhonov regularization
projektowanie cewki
programowanie kwadratowe
regularyzacja Tikhonova
Opis:
In this work, the problem of coil design is studied. It is assumed that the structure of the coil is known (i.e., the positions of simple circular coils are fixed) and the problem is to find current distribution to obtain the required magnetic field in a given region. The unconstrained version of the problem (arbitrary currents are allowed) can be formulated as a Least-SQuares (LSQ) problem. However, the results obtained by solving the LSQ problem are usually useless from the application point of view. Moreover, for higher dimensions the problem is ill-conditioned. To overcome these difficulties, a regularization term is sometimes added to the cost function, in order to make the solution smoother. The regularization technique, however, produces suboptimal solutions. In this work, we propose to solve the problem under study using the constrained Quadratic Programming (QP) method. The methods are compared in terms of the quality of the magnetic field obtained, and the power of the designed coil. Several 1D and 2D examples are considered. It is shown that for the same value of the maximum current the QP method provides solutions with a higher quality magnetic field than the regularization method.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2014, 24, 2; 249-257
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Regularization of non-coercive quasi variational inequalities
Autorzy:
Giannessi, F.
Khan, A.
Powiązania:
https://bibliotekanauki.pl/articles/205586.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
operator monotoniczny i pseudomonotoniczny
zbieżność
convergence
monotone and pseudo-monotone operators
non-coercive
quasi-variational inequalities
regularization
Opis:
This paper is devoted to the regularization of quasi-variational inequalities. The quasi-variational inequality is considered with multivalued operator. The operator involved is taken to be non-coercive and the data are assumed to be known approximately only. Under the assumption that the quasi-variational inequality be solvable, a weakly convergent approximation procedure is designed by means of the so-called Browder-Tikhonov regularization method.
Źródło:
Control and Cybernetics; 2000, 29, 1; 91-110
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adaptation of the Regularization Parameters in the Nm-Delta Networks
Autorzy:
Gołąbek, P.
Kosiński, W.
Powiązania:
https://bibliotekanauki.pl/articles/911150.pdf
Data publikacji:
2000
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
regularyzacja
Levenberg-Marquardt
NM-Delta
M-Delta
regularization
quasi-Newton
Opis:
The paper describes an application of regularization techniques to an automatic choice of parameters driving the learning process in the NM-Delta neural network architecture. The heterogeneous learning algorithm is identified as very similar to the Levenberg-Marquardt method but with a considerably smaller computational cost and different justification of parameter selection. The performance of the modified algorithm proves to be comparable with that of the Levenberg-Marquardt.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2000, 10, 4; 779-790
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł

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