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Wyszukujesz frazę "local error" wg kryterium: Temat


Tytuł:
Local error structures and order conditions in terms of Lie elements for exponential splitting schemes
Autorzy:
Auzinger, W.
Herfort, W.
Powiązania:
https://bibliotekanauki.pl/articles/255869.pdf
Data publikacji:
2014
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
exponential splitting schemes
local error
defect
order conditions
free Lie algebra
Opis:
We discuss the structure of the local error of exponential operator splitting methods. In particular, it is shown that the leading error term is a Lie element, i.e., a linear combination of higher-degree commutators of the given operators. This structural assertion can be used to formulate a simple algorithm for the automatic generation of a minimal set of polynomial equations representing the order conditions, for the general case as well as in symmetric settings.
Źródło:
Opuscula Mathematica; 2014, 34, 2; 243-256
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Methods of Step-Size Distribution Optimization Used in S-SSFM Simulations of WDM Systems
Autorzy:
Jaworski, M.
Powiązania:
https://bibliotekanauki.pl/articles/308958.pdf
Data publikacji:
2009
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
local error method
logarithmic step
simulation
split-step Fourier method
WDM
Opis:
Brief review of methods used for simulation of signal propagation in wavelength division multiplexed (WDM)links is presented. We propose two novel methods of stepsize distribution optimization used to improve symmetrized split step Fourier method (S-SSFM) numerical efficiency: presimulated local error S-SSFM (PsLE S-SSFM) and modified logarithmic (ML S-SSFM). The PsLE S-SSFM contains two stages: in the initial stage step-size distribution optimization is carried out by combining local error method and presimulation with signal spectrum averaging; in the second stage conventional SSFM is used by applying optimal step-size distribution obtained in the initial stage. The ML S-SSFMis generalization of logarithmic method proposed to suppress spurious FWM tones, in which a slope of logarithmic step-size distribution is optimized. Overall time savings exceed 50%, depending of a simulated system scenario.
Źródło:
Journal of Telecommunications and Information Technology; 2009, 1; 44-50
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new nonlinear L-stable scheme with constant and adaptive step-size strategy
Autorzy:
Arain, Sadia
Qureshi, Sania
Shaikh, Asif Ali
Powiązania:
https://bibliotekanauki.pl/articles/2175496.pdf
Data publikacji:
2021
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
stiff systems
singular systems
L-stability
local error
order stars
systemy sztywne
układ singularny
stabilność L
błąd lokalny
Opis:
The present study proposes a new explicit nonlinear scheme that solves stiff and nonlinear initial value problems in ordinary differential equations. One of the promising features of this scheme is its fourth-order convergence with strong stability having an unbounded region. A modern approach for relative stability growth analysis is also presented under order stars conditions. The scheme is also good in dealing with singular and stiff type of models. Comparing numerical experiments using various errors, including maximum absolute global error over the integration interval, absolute error at the endpoint, average error, norm of errors, and the CPU times (seconds), shows better performance. An adaptive step-size approach seems to increase the performance of the proposed scheme. The numerical simulations assure us of L -stability, consistency, order, and rapid convergence.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2021, 20, 4; 7--18
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A local truncation error estimation for a SubIval solver
Autorzy:
Sowa, M.
Powiązania:
https://bibliotekanauki.pl/articles/202058.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
fractional calculus
numerical method
adaptive step size
local truncation error
circuit analysis
rachunek różniczkowy
metoda numeryczna
analiza obwodów
Opis:
The paper concerns an analysis for SubIval (the subinterval-based method for fractional derivative computations in initial value problems). A time step size adaptive solver is discussed, for which the formula of a local truncation error is derived. A general form for a system of linear equations is given for the considered class of problems (for which the analysis is performed in the paper). Two circuit examples are introduced to display the usefulness of the SubIval solver. For the examples that have been chosen it is possible to obtain referential solutions through completely different methods. The results obtained through the numerical solver are compared with evaluations of the referential solutions. The error estimation results obtained for the time steps of the SubIval solver are compared with the actual errors, being the differences between the numerical solutions and the referential solutions. The paper also contains a comparison of the accuracy of results obtained through the SubIval solver with the accuracies of other solvers.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2018, 66, 4; 475-484
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Use of partial derivatives to derive a convergent numerical scheme with its error estimates
Autorzy:
Qureshi, Sania
Adeyeye, Oluwaseun
Shaikh, Asif Ali
Powiązania:
https://bibliotekanauki.pl/articles/122734.pdf
Data publikacji:
2019
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
multi-derivative
local truncation error
stability
absolute relative errors
consistency
principal term
wielopochodna
pochodna cząstkowa
schemat numeryczny
błąd względny
błąd bezwzględny
Opis:
Using the idea of the partial derivative with respect to the ordinate of a given mathematical function, a new numerical scheme having third order convergence has been devised for solving initial value problems in ordinary differential equations. Such problems are deemed to be indispensable in diverse fields of science, medical and engineering and are most often required to be solved by the numerical schemes. In view of this, the proposed numerical scheme is found to be efficient in solving both autonomous and non-autonomous type of problems as supported by some numerical experiments in the present study. Using the Taylor expansion for the slopes involved in the scheme, the leading term of the local truncation error is shown to have contained Ϭ(h4) which proves third order accuracy of the scheme. In addition to this, consistency and linear stability analysis of the proposed scheme has extensively been discussed. Numerical experiments show better performance of the proposed numerical scheme when compared with existing numerical schemes of the same order as that of the scheme proposed. CPU time (seconds), maximum absolute relative error and the absolute relative error, computed at the last grid point of the integration interval for the associated initial value problem, are the parameters to test the performance of the proposed numerical scheme. MATLAB Version: 9.4.0.813654 (R2018a) in double-precision on a personal computer equipped with a Processor Intel (R) Core(TM) i3-4500U CPU@ 1.70 GHz running under the Windows 10 operating system has been employed in order to carry out all the required numerical computations.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2019, 18, 4; 73-83
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimation of Measurement Error Using Local Sampling and Joint Nonparametric Linearisation
Estymowanie błędu pomiarowego z zastosowaniem łącznej nieparametrycznej linearyzacji prób lokalnych
Autorzy:
Górkiewicz, Maciej
Powiązania:
https://bibliotekanauki.pl/articles/906540.pdf
Data publikacji:
2002
Wydawca:
Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego
Tematy:
local sampling
linearisation
measurement error
neear neighbours
Opis:
This paper presents how to use the near neighbours technique in aim to transform a given data set (Z, X, YT) of size N into a set of J ~ N local samples (Z, X), with restrictions on minimal number К of members in each local sample and on maximal difference of Y inside each local sample, where Z plays role of an outcome, X is an independent variable, and Y1 - (Y ..., YL) is a vector of L supplementary continuous variables. Then the procedure for non-parametric joint linearisation of an obtained set of local samples was proposed. The whole proposed method was applied to estimation of models with standard deviation of measurements as outcome Z and measured value as independent variable X. The paper was inspired by difficulties with estimation of the measurement error, which often occur in medicine, if accuracy of a measurement procedure depends on some properties of patient. Nevertheless, the proposed approach seems to be more general. It can be useful in many analyses of observational studies, which aim to estimate a family of the functions, preferable the linear ones, instead a single multivariate model.
Praca prezentuje zastosowanie techniki najbliższych sąsiadów w celu przekształcenia zbioru N danych postaci (Z, X, YT) w zbiór J ~ N prób lokalnych (Z, X), przy ograniczeniach dotyczących minimalnej liczby danych К oraz różnic wartości YT w każdej próbie lokalnej, gdzie Z pełni rolę zmiennej zależnej, X - zmiennej niezależnej, a Y1 = (Y, ..., YL) jest L-wymiarową zmienną dodatkową. Następnie proponuje się procedurę nieparametrycznej łącznej linearyzacji zbioru prób lokalnych. Obie procedury proponuje się stosować do oceny dokładności metod pomiarowych, z odchyleniem standardowym błędu pomiarów jako zmienną Z i wielkością mierzoną jako zmienną X. Proponowane podejście może być użyteczne w innych zastosowaniach, kiedy zamiast modelu regresji wielowymiarowej estymuje się rodzinę zależności regresyjnych.
Źródło:
Acta Universitatis Lodziensis. Folia Oeconomica; 2002, 162
0208-6018
2353-7663
Pojawia się w:
Acta Universitatis Lodziensis. Folia Oeconomica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of mesh refinement on results of elastic-plastic FEM analysis
Autorzy:
Szabracki, P.
Lipiński, T.
Powiązania:
https://bibliotekanauki.pl/articles/297864.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Warmińsko-Mazurski w Olsztynie
Tematy:
FEM analysis
local mesh refinement
elastic-plastic deformation
error optimization
Opis:
To improve fitting of numerical results to experimental data, in the past, distances between nodes were decreased for whole mesh. A typical mesh generator for Finite Element Method (FEM) analysis ensures possibility to decrease distances between nodes for edges or surfaces of described geometries. Influence of local mesh refinement for a flat and round tensile specimen on fitting of numerical tensile simulation results to experimental data was presented in the paper. Local mesh refinement was performed for areas with the error values higher than threshold value. First iteration of flat and round mesh refinement has to improved correlation of numerical and experimental data with acceptable increase of mesh file size. Similar observations have been made for the second iteration of the flat specimen mesh. On the basis of analysis, shown that second iteration of round mesh refinement caused crucial increase of mesh file size and computation time with negligible fitting improvement.
Źródło:
Technical Sciences / University of Warmia and Mazury in Olsztyn; 2014, 17(2); 149-163
1505-4675
2083-4527
Pojawia się w:
Technical Sciences / University of Warmia and Mazury in Olsztyn
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of the gear local damage and profile error of the gear on the drivetrain dynamic response
Autorzy:
Ghorbel, A.
Zghal, B.
Abdennadher, M.
Walha, L.
Haddar, M.
Powiązania:
https://bibliotekanauki.pl/articles/280233.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
dynamic behaviour
clutch
gear
brake disc
gear local damage
gear profile error
Opis:
The dynamic modeling of vibration of a drivetrain is used for increasing our information about vibration generating mechanisms, especially in the presence of some kind of gear faults. This paper describes a research work on the automotive driveline modeling, vibration analysis, and the effect of gear defects on the dynamic behavior of the system. Firstly, main drivetrain components including the engine, clutch, single stage spur gearbox and disc brake are modeled, respectively. The nonlinear dynamic model is simulated by a thirteen degrees of freedom (DOF) system and the nonlinear function is due to the dry friction path. Secondly, two types of defects are modeled and introduced into the spur gear system; local damage and profile error. Then, the nonlinear equations of motion are solved by the numerical Runge Kutta method and a comparative study of the dynamic behavior of the system in healthy and defected cases is discussed for each fault type. The influence of the defects on the vibration response is presented in the time and frequency domain. Finally, analysis of the two defects together is presented.
Źródło:
Journal of Theoretical and Applied Mechanics; 2018, 56, 3; 765-779
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Strong consistency of the local linear relative regression estimator for censored data
Autorzy:
Bouhadjera, Feriel
Saïd, Elias Ould
Powiązania:
https://bibliotekanauki.pl/articles/29519178.pdf
Data publikacji:
2022
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
censored data
local linear approach
relative error
regression function
uniform almost sure convergence
Opis:
In this paper, we combine the local linear approach to the relative error regression estimation method to build a new estimator of the regression operator when the response variable is subject to random right censoring. We establish the uniform almost sure consistency with rate over a compact set of the proposed estimator. Numerical studies, firstly on simulated data, then on a real data set concerning the death times of kidney transplant patients, were conducted. These practical studies clearly show the superiority of the new estimator compared to competitive estimators.
Źródło:
Opuscula Mathematica; 2022, 42, 6; 805-832
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Performance of variance function estimators for autoregressive time series of order one: asymptotic normality and numerical study
Autorzy:
Borkowski, P.
Mielniczuk, J.
Powiązania:
https://bibliotekanauki.pl/articles/206217.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
autoregressive process
bandwidth
heteroscedasticity
integrated squared error
local linear and local maximum likelihood estimator
difference-based estimator
geometric moment contraction
variance function
volatility
Opis:
We study performance of several conditional variance estimators for an autoregressive time series which include local linear smoothers with various bandwidths, local likelihood and difference-based estimators. In the theoretical part, asymptotic normality of the local linear estimator of variance with no mixing assumptions imposed on the underlying process is proved. Moreover, numerical examples performed reveal that a two-stage local linear smoother with a bandwidth, proposed by Ruppert, Sheather and Wand, used to estimate the regression function and a simple rule of thumb bandwidth for variance estimation performs best for variances without much structure, whereas the bandwidth considered by Fan and Yao works very well for much more variable variances.
Źródło:
Control and Cybernetics; 2012, 41, 2; 415-441
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł

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