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Wyszukujesz frazę "nonlinear function" wg kryterium: Temat


Tytuł:
Existence of positive continuous weak solutions for some semilinear elliptic eigenvalue problems
Autorzy:
Zeddini, Noureddine
Sari, Rehab Saeed
Powiązania:
https://bibliotekanauki.pl/articles/2216186.pdf
Data publikacji:
2022
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
Green function
Kato class
nonlinear elliptic systems
positive solution
maximum principle
Schauder fixed point theorem
Opis:
Let D be a bounded $C^(1,1)$ -domain in $R^d$, d ≥ 2. The aim of this article is twofold. The first goal is to give a new characterization of the Kato class of functions $K(D)$ that was defined by $N$. Zeddini for $d = 2$ and by $H$. Mâagli and M. Zribi for $d ≥ 3$ and adapted to study some nonlinear elliptic problems in $D$. The second goal is to prove the existence of positive continuous weak solutions, having the global behavior of the associated homogeneous problem, for sufficiently small values of the nonnegative constants $λ$ and $μ$ to the following system $Δu = λf(x, u, v)$, $Δv = μg(x, u, v)$ in D, $u = ϕ_1$ and $v = ϕ_2$ on $∂D$, where $ϕ_1$ and $ϕ_2$ are nontrivial nonnegative continuous functions on $∂D$. The functions $f$ and g are nonnegative and belong to a class of functions containing in particular all functions of the type $f(x, u, v) = p(x)u^(α) h_1 (v)$ and $g(x, u, v) = q(x)h_2 (u)v^β$ with $α ≥ 1$, $β ≥ 1$, $h_1$, $h_2$ are continuous on $[0,∞)$ and $p$, $q$ are nonnegative functions in $K(D)$.
Źródło:
Opuscula Mathematica; 2022, 42, 3; 489-519
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Note on describing function analysis of fractional order nonlinear control systems
Autorzy:
Yeroglu, C.
Tan, N.
Powiązania:
https://bibliotekanauki.pl/articles/206045.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
describing function
fractional order control
limit cycle
nonlinear systems
relay auto-tuning
stability margin
Opis:
This paper presents extensions of some results, obtained for the analysis of classical nonlinear control systems, to the nonlinear fractional order systems. It is shown that the results related to limit cycle prediction using describing function method can be applied to the fractional order plants. The frequency and the amplitude of the limit cycle are used for auto-tuning of the PID controller for nonlinear control systems with fractional order transfer functions. Fractional order control system with parametric uncertainty is also considered for the nonlinear case. On the other hand, a New method is provided for stability margin computation for fractional order nonlinear control system with parametric uncertainty structure using the Nyquist envelopes of the fractional order uncertain plant and the describing function that represents the nonlinearity of the system. Maximum perturbation bounds of the parameters of the fractional order plant are computed. Numerical examples are included to illustrate the methods presented.
Źródło:
Control and Cybernetics; 2015, 44, 2; 233-255
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A backstepping approach to ship course control
Autorzy:
Witkowska, A.
Tomera, M.
Śmierzchalski, R.
Powiązania:
https://bibliotekanauki.pl/articles/911245.pdf
Data publikacji:
2007
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
sterowanie nieliniowe
algorytm genetyczny
sterowanie statkiem
funkcja Lapunowa
backstepping
nonlinear control
genetic algorithms
ship control
Lyapunov function
Opis:
As an object of course control, the ship is characterised by a nonlinear function describing static manoeuvring characteristics that reflect the steady-state relation between the rudder deflection and the rate of turn of the hull. One of the methods which can be used for designing a nonlinear ship course controller is the backstepping method. It is used here for designing two configurations of nonlinear controllers, which are then applied to ship course control. The parameters of the obtained nonlinear control structures are tuned to optimise the operation of the control system. The optimisation is performed using genetic algorithms. The quality of operation of the designed control algorithms is checked in simulation tests performed on the mathematical model of a tanker. In order to obtain reference results to be used for comparison with those recorded for nonlinear controllers designed using the backstepping method, a control system with the PD controller is examined as well.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2007, 17, 1; 73-85
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An energy-based method in phenomenological description of mechanical properties of nonlinear materials under plane stress
Autorzy:
Wegner, T.
Kurpisz, D.
Powiązania:
https://bibliotekanauki.pl/articles/279443.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
energy-based method
nonlinear material
phenomenological description
strain energy density function
Sylvester’s theorem
Opis:
A method based on energy is a very useful tool for description of mechanical properties of materials. In the current paper, on the base of geometrical interpretation of a deformation process, the strain energy density function for isotropic nonlinear materials has been constructed. On account of hydrostatic interpretation of the volumetric deformation, the elastic part of energy has been extracted. The initiation of the damage process due to plastic flow of the material under plane stress has been determined and the stability conditions have been formulated by using in the stability analysis the strain energy density function in addition to Sylvester’s theorem and assumption of zero volume change during pure plastic deformations. This concept is an original part of the work and continuation of the investigations previously carried out by Wegner and Kurpisz. The theoretical investigations have been illustrated on the example of aluminium.
Źródło:
Journal of Theoretical and Applied Mechanics; 2017, 55, 1; 129-139
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A simplified elliptical function solution for coupled nonlinear vibration of multilayer graphene sheets
Autorzy:
Venkatraman, G.
Suji, D.
Powiązania:
https://bibliotekanauki.pl/articles/2086951.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
nonlinear coupled vibration
nonlinear van der Waals force
Multilayer Graphene Sheets
elliptical function
exact solution
Opis:
This paper presents a simple exact solution for coupled nonlinear free vibration analysis of Multilayer Graphene Sheets (MLGS) using elliptical functions. Though elliptical functions are used in nonlinear dynamics, they are employed to find the exact solution of a coupled system for the first time. The nonlinear dynamic equation including geometric nonlinearity and Eringen nonlocal theory is uncoupled by elliptical functions, and exact solutions for simply supported boundary conditions are obtained. The results are compared with the harmonic balance method. The nonlinear frequency of MLGS is studied for its effects with a small scale parameter, and the linear and nonlinear van der Waals force.
Źródło:
Journal of Theoretical and Applied Mechanics; 2022, 60, 1; 3--16
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Digital volume correlation in an environment with intensive salt-and-pepper noise and strong monotonic nonlinear distortion of light intensity
Autorzy:
Tu, P.
Bai, Y.
Xu, W.
Dong, B.
Ye, S.
Yang, Q.
Zhou, Y.
Powiązania:
https://bibliotekanauki.pl/articles/173712.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
digital volume correlation
correlation function
salt-and-pepper noise
nonlinear effects
Opis:
Digital volume correlation is an image-based technique for internal 3D displacement and strain fields measurement or analysis widely used in the field of experimental mechanics. A widely used correlation function (criterion) of digital volume correlation is Pearson correlation function, which suffers from the problem of the acquired data being contaminated by salt-and-pepper noise and monotonic nonlinear distortion of the light intensity. In this work, a 3D correlation function called the Spearman correlation function is used to deal with those interferences. A numerical experiment shows that the performance of Spearman correlation function using integer-pixel registration in an environment with 10% salt-and-pepper noise is better than that of Spearman and Pearson correlation functions using sub-pixel registration in an environment with 1% salt-and-pepper noise. As the light intensity distortion is significant, the error of Pearson correlation function is considerable; meanwhile, the error of Spearman correlation function is small. In conclusion, Spearman correlation function is, in particular, practical and useful in digital volume correlation.
Źródło:
Optica Applicata; 2017, 47, 2; 209-223
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ruch cieczy w zbiorniku poziomym
Motion of liquid at tank at horizontal motion
Autorzy:
Trębacki, K.
Królicka, A.
Powiązania:
https://bibliotekanauki.pl/articles/317332.pdf
Data publikacji:
2016
Wydawca:
Instytut Naukowo-Wydawniczy "SPATIUM"
Tematy:
zbiornik prostopadłościenny
ładunek płynny
ruch ładunku
ruch poziomy
ruchy cieczy w zbiorniku
ciśnienia na ścianach zbiornika
obliczenia matematyczne działania zbiornika
teoria liniowa
teoria nieliniowa
funkcja potencjału
rectangular tank
liquid cargo
movement of liquid cargo
horizontal motion
ship's motion
ship rolling
movement of liquid in vessel
pressure on walls of tank
linear theory
nonlinear theory
potential function
Opis:
W artykule omówiony został ruch poziomy zbiornika wypełnionego cieczą. Wymieniono przyczyny ruchu cieczy w zbiorniku. Dokonano analizy wg teorii liniowej i nieliniowej. Wyznaczono częstości drgań własnych. Na podstawie teorii liniowej i nieliniowej wyznaczono funkcję potencjału prędkości Φ i powierzchni swobodnej η. Podano rozkłady ciśnień hydrodynamicznych na ściankach zbiornika.
The article discussed a horizontal motion of tank filled with liquid. Discussed a causes of motion of liquid in the tank. Were made analysis by the theory of linear and nonlinear. In article the given of frequency of vibration. On the basis of theory of linear and nonlinear function are determined velocity potential and free surface. Given of distributions of hydrodynamic pressure on the walls of tank.
Źródło:
Autobusy : technika, eksploatacja, systemy transportowe; 2016, 17, 10; 97-102
1509-5878
2450-7725
Pojawia się w:
Autobusy : technika, eksploatacja, systemy transportowe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Water entry of a wedge into waves in three degrees of freedom
Autorzy:
Sun, Shi Yan
Chen, Hai Long
Xu, Gang
Powiązania:
https://bibliotekanauki.pl/articles/259045.pdf
Data publikacji:
2019
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
water entry
nonlinear waves
three degrees of freedom
boundary element method
auxiliary function method
Opis:
The hydrodynamic problem of a two-dimensional wedge entering into a nonlinear wave in three degrees of freedom is investigated based on the incompressible velocity potential theory. The problem is solved through the boundary element method in the time domain. To avoid numerical difficulties due to an extremely small contact area at the initial stage, a stretched coordinate system is used based on the ratio of the Cartesian system in the physical space to the distance travelled by the wedge in the vertical direction. The mutual dependence of body motion and wave loading is decoupled by using the auxiliary function method. Detailed results about body accelerations, velocities and displacements at different Froude numbers or different waves are provided, and the mutual effect between body motion and wave loading is analysed in depth.
Źródło:
Polish Maritime Research; 2019, 1; 117-124
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Antiplane deformation of a bimaterial with thin interfacial nonlinear elastic inclusion
Autorzy:
Sulym, H.
Piskozub, Y.
Polanski, J.
Powiązania:
https://bibliotekanauki.pl/articles/386464.pdf
Data publikacji:
2018
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
antiplane deformation
longitudinal shear
nonlinear elasticity
interfacial crack
thin inclusion
stress intensity factor
bimaterial
jump function
singular integral equation
Opis:
The problem of longitudinal shear of bimaterial with thin nonlinear elastic inclusion at the interface of matrix materials is considered. Solution of the problem is constructed using the boundary value problem of combining analytical functions and jump functions method. The model of the thin inclusion with nonlinear resilient parameters is built. Solution of the problem is reduced to a system of singular integral equations with variable coefficients. The convergent iterative method for solving such a system is offered for various nonlinear strain models, including Ramberg-Osgood law. Numerical calculations are carried out for different values of non-linearity characteristic parameters for the inclusion material. Their parameters are analysed for the tensely-deformed matrix under loading a uniformly distributed shear stresses and for a balanced system of the concentrated forces.
Źródło:
Acta Mechanica et Automatica; 2018, 12, 3; 190-195
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Two steps piecewise affine identification of nonlinear systems
Autorzy:
Stevek, J.
Szucs, A.
Kvasnica, M.
Fikar, M.
Kozak, S.
Powiązania:
https://bibliotekanauki.pl/articles/229499.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
piecewise affine systems
piecewise linear
approximation
nonlinear systems
orthogonal polynomials
basis function expansion
Opis:
Given a set of input-output measurements, the paper proposes a method for approximation of a nonlinear system by a piecewise affine model (PWA). First step of the two-stage procedure is identification from input-output data, in order to obtain an appropriate nonlinear function in analytic form. The analytic expression of the model can be represented either by a static nonlinear function or by a dynamic system and can be obtained using a basis function expansion modeling approach. Subsequently we employ nonlinear programming to derive optimal PWA approximation of the identified model such that the approximation error is minimized. Moreover, we show that approximation of multivariate systems can be transformed into a series of one-dimensional approximations, which can be solved efficiently using standard optimization techniques.
Źródło:
Archives of Control Sciences; 2012, 22, 4; 371-388
1230-2384
Pojawia się w:
Archives of Control Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Aproksymacja nieliniowych charakterystyk maszyn elektrycznych prądu przemiennego wielomianami potęgowymi wielu zmiennych
Approximation of Nonlinear Characteristics of AC Machines by Multivariable Power Polynomials
Autorzy:
Sobczyk, T. J.
Warzecha, A.
Mazgaj, W.
Powiązania:
https://bibliotekanauki.pl/articles/1368195.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Napędów i Maszyn Elektrycznych Komel
Tematy:
maszyny elektryczne
nieliniowość magnetyczna
nieliniowe charakterystyki uzwojeń
aproksymacja funkcji ko-energii magnetycznej
electrical machines
magnetic nonlinearity
nonlinear winding characteristics
approximation of magnetic co-energy function
Opis:
To model non-linearity of magnetic circuit of alternating current machines at circuit approach it is necessary to know, so called, characteristic of windings determining leakage fluxes as of each winding as a function of currents of all machine windings. Such functions can be approximated by multivariable Power series of currents. However, it leads to rather complicated relationships between a set of such functions. The paper presents a methodology for computation of the coefficients of those multivariable power series bases on values of the co-energy and the winding leakage fluxes, or eventually dynamic inductances, using the linear regression method. Combining those values reduces time and costs of numerical computations necessary for its calculations.
W celu uwzględnienia nieliniowości obwodu magnetycznego maszyny elektrycznej w modelach obwodowych należy wyznaczyć tzw. charakterystyki uzwojeń maszyny określające strumienie skojarzone każdego z uzwojeń jako funkcje prądów wszystkich uzwojeń. Ich aproksymacja jest - w zasadzie - możliwa tylko za pomocą wielomianów potęgowych wielu zmiennych. Prowadzi to do bardzo złożonych relacji między funkcjami aproksymującymi. W pracy zaproponowano modyfikację metodyki określania współczynników występujących w tych wielomianach na podstawie zbioru wartości ko-energii magnetycznej oraz strumieni skojarzonych lub dodatkowo indukcyjności dynamicznych przy wykorzystaniu metody regresji liniowej. Jednoczesne wykorzystanie wartości ko-energii magnetycznej oraz strumieni skojarzonych ma na celu ograniczenie czasu i kosztów obliczeń numerycznych potrzebnych dla ich obliczania.
Źródło:
Maszyny Elektryczne: zeszyty problemowe; 2013, 3, 100/1; 101-105
0239-3646
2084-5618
Pojawia się w:
Maszyny Elektryczne: zeszyty problemowe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of shock absorber characteristics’ nonlinearities on suspension Frequency Response Function estimation and possibilities of simplified characteristics modelling
Autorzy:
Ślaski, Grzegorz
Klockiewicz, Zbyszko
Powiązania:
https://bibliotekanauki.pl/articles/2124767.pdf
Data publikacji:
2022
Wydawca:
Sieć Badawcza Łukasiewicz. Przemysłowy Instytut Motoryzacji
Tematy:
shock absorber
damper
frequency response function
estimation
nonlinear
damper model
bilinear
Opis:
The paper shortly presents shock absorber design evolution and resulting achieved characteristics. The way in which suspension performance is evaluated is described giving information about models used for suspension parameter tuning during simulation testing of suspension transmissibility (FRF - Frequency Response Function) for most important suspension assessment criteria. More detailed information about models of shock absorber (damper) nonlinearities of characteristics allows for description of methods of linear and nonlinear suspension models FRF estimation. Testing linear suspension model is possible with the use of analytical transfer function formulas which were used to verify methods for estimation FRF using estimated power spectral density functions of excitation and response signals. Designing appropriate input signal allowing to get useful response signals was necessary to for the success of this research. Proposed FRF estimation method was used for linear estimation of nonlinear suspension for a given range of working condition. It was demonstrated that there is no single value of a damping coefficient which would make the linear model responses similar to the responses of the nonlinear one. Then the bilinear model was proposed, giving good damper static nonlinear characteristic.
Źródło:
Archiwum Motoryzacji; 2022, 96, 2; 77--95
1234-754X
2084-476X
Pojawia się w:
Archiwum Motoryzacji
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fundamental limitations of the decay of generalized energy in controlled (discrete-time) nonlinear systems subject to state and input constraints
Autorzy:
Selek, István
Ikonen, Enso
Powiązania:
https://bibliotekanauki.pl/articles/330074.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
decay rate maximization
Lyapunov function
nonlinear control system
rozkład wykładniczy
funkcja Lapunowa
układ sterowania nieliniowy
Opis:
This paper is devoted to the analysis of fundamental limitations regarding closed-loop control performance of discrete-time nonlinear systems subject to hard constraints (which are nonlinear in state and manipulated input variables). The control performance for the problem of interest is quantified by the decline (decay) of the generalized energy of the controlled system. The paper develops (upper and lower) barriers bounding the decay of the system’s generalized energy, which can be achieved over a set of asymptotically stabilizing feedback laws. The corresponding problem is treated without the loss of generality, resulting in a theoretical framework that provides a solid basis for practical implementations. To enhance understanding, the main results are illustrated in a simple example.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2019, 29, 4; 629-639
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Method for Constructing ε-value Functions for The Bolza Problem of Optimal Control
Autorzy:
Pustelnik, J.
Powiązania:
https://bibliotekanauki.pl/articles/911140.pdf
Data publikacji:
2005
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
optymalizacja nieliniowa
sterowanie optymalne
równanie Hamiltona-Jacobiego
programowanie dynamiczne
wartość funkcji
nonlinear optimization
Bolza problem
optimal control
Hamilton-Jacobi equation
dynamic programming
value function
approximate minimum
Opis:
The problem considered is that of approximate minimisation of the Bolza problem of optimal control. Starting from Bellman's method of dynamic programming, we define the ε-value function to be an approximation to the value function being a solution to the Hamilton-Jacobi equation. The paper shows an approach that can be used to construct an algorithm for calculating the values of an ε-value function at given points, thus approximating the respective values of the value function.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2005, 15, 2; 177-186
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling nonlinear road traffic networks for junction control
Autorzy:
Péter, T.
Powiązania:
https://bibliotekanauki.pl/articles/330975.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
modelowanie matematyczne
układ dodatni nieliniowy
liniowa funkcja Lapunowa
mathematical modeling
mathematical control
traffic networks
nonlinear positive system
linear Lyapunov function
Opis:
The paper introduces a method of mathematical modeling of high scale road traffic networks, where a new special hypermatrix structure is intended to be used. The structure describes the inner-inner, inner-outer and outer-outer relations, and laws of a network area. The research examines the nonlinear equation system. The analysed model can be applied to the testing and planning of large-scale road traffic networks and the regulation of traffic systems. The elaborated model is in state space form, where the states are vehicle densities on a particular lane and the dynamics are described by a nonlinear state constrained positive system. This model can be used directly for simulation and analysis and as a starting point for investigating various control strategies. The stability of the traffic over the network can be analyzed by constructing a linear Lyapunov function and the associated theory. The model points out that in intersection control one must take the traffic density values of both the input and the output sections into account. Generally, the control of any domain has to take the density of input and output sections into consideration.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2012, 22, 3; 723-732
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł

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