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Wyszukujesz frazę "Differential equation" wg kryterium: Temat


Tytuł:
A criterion for convergence of solutions of homogeneous delay linear differential equations
Autorzy:
Diblík, Josef
Powiązania:
https://bibliotekanauki.pl/articles/1293891.pdf
Data publikacji:
1999
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
topological principle of Ważewski (Rybakowski's approach)
asymptotic convergence of solutions
linear homogeneous delay differential equation
Opis:
The linear homogeneous differential equation with variable delays
$ ẏ(t) = ∑_{j=1}^n α_j(t)[y(t) - y(t-τ_j(t))]$
is considered, where $α_j ∈ C(I,ℝ͞͞⁺)$, I = [t₀,∞), ℝ⁺ = (0,∞), $∑_{j=1}^n α _j(t) > 0$ on I, $τ_j ∈ C(I,ℝ⁺),$ the functions $t - τ_j(t)$, j=1,...,n, are increasing and the delays $τ_j$ are bounded. A criterion and some sufficient conditions for convergence of all solutions of this equation are proved. The related problem of nonconvergence is also discussed. Some comparisons to known results are given.
Źródło:
Annales Polonici Mathematici; 1999, 72, 2; 115-130
0066-2216
Pojawia się w:
Annales Polonici Mathematici
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A dynamic bi-orthogonal field equation approach to efficient Bayesian inversion
Autorzy:
Tagade, P. M.
Choi, H. L.
Powiązania:
https://bibliotekanauki.pl/articles/330516.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
Bayesian framework
stochastic partial differential equation
Karhunen–Loève expansion
generalized polynomial chaos
dynamically biorthogonal field equations
ramy Bayesa
stochastyczne równanie różniczkowe
przekształcenie Karhunena-Loeve'a
chaos wielomianowy
Opis:
This paper proposes a novel computationally efficient stochastic spectral projection based approach to Bayesian inversion of a computer simulator with high dimensional parametric and model structure uncertainty. The proposed method is based on the decomposition of the solution into its mean and a random field using a generic Karhunen–Loève expansion. The random field is represented as a convolution of separable Hilbert spaces in stochastic and spatial dimensions that are spectrally represented using respective orthogonal bases. In particular, the present paper investigates generalized polynomial chaos bases for the stochastic dimension and eigenfunction bases for the spatial dimension. Dynamic orthogonality is used to derive closed-form equations for the time evolution of mean, spatial and the stochastic fields. The resultant system of equations consists of a partial differential equation (PDE) that defines the dynamic evolution of the mean, a set of PDEs to define the time evolution of eigenfunction bases, while a set of ordinary differential equations (ODEs) define dynamics of the stochastic field. This system of dynamic evolution equations efficiently propagates the prior parametric uncertainty to the system response. The resulting bi-orthogonal expansion of the system response is used to reformulate the Bayesian inference for efficient exploration of the posterior distribution. The efficacy of the proposed method is investigated for calibration of a 2D transient diffusion simulator with an uncertain source location and diffusivity. The computational efficiency of the method is demonstrated against a Monte Carlo method and a generalized polynomial chaos approach.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2017, 27, 2; 229-243
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A finite difference method for nonlinear parabolic-elliptic systems of second-order partial differential equations
Autorzy:
Malec, M.
Sapa, L.
Powiązania:
https://bibliotekanauki.pl/articles/255499.pdf
Data publikacji:
2007
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
partial differential equation
parabolic-elliptic system
finite difference method
finite difference scheme
consistence
convergence
stability
error estimate
uniqueness
Opis:
This paper deals with a finite difference method for a wide class of weakly coupled nonlinear second-order partial differential systems with initial condition and weakly coupled nonlinear implicit boundary conditions. One part of each system is of the parabolic type (degenerated parabolic equations) and the other of the elliptic type (equations with a parameter) in a cube in R1+n. A suitable finite difference scheme is constructed. It is proved that the scheme has a unique solution, and the numerical method is consistent, convergent and stable. The error estimate is given. Moreover, by the method, the differential problem has at most one classical solution. The proof is based on the Banach fixed-point theorem, the maximum principle for difference functional systems of the parabolic type and some new difference inequalities. It is a new technique of studying the mixed-type systems. Examples of physical applications and numerical experiments are presented.
Źródło:
Opuscula Mathematica; 2007, 27, 2; 259-289
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A general class of McKean-Vlasov stochastic evolution equations driven by Brownian motion and Lèvy process and controlled by Lèvy measure
Autorzy:
Ahmed, N.
Powiązania:
https://bibliotekanauki.pl/articles/729570.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
McKean-Vlasov stochastic differential equation
Hilbert spaces
existence of optimal controls
Opis:
In this paper we consider McKean-Vlasov stochastic evolution equations on Hilbert spaces driven by Brownian motion and L`evy process and controlled by L`evy measures. We prove existence and uniqueness of solutions and regularity properties thereof. We consider weak topology on the space of bounded Le´vy measures on infinite dimensional Hilbert space and prove continuous dependence of solutions with respect to the Le´vy measure. Then considering a certain class of Le´vy measures on infinite as well as finite dimensional Hilbert spaces, as relaxed controls, we prove existence of optimal controls for Bolza problem and some simple mass transport problems
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2016, 36, 2; 181-206
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A general transfer function representation for a class of hyperbolic distributed parameter systems
Autorzy:
Bartecki, K.
Powiązania:
https://bibliotekanauki.pl/articles/330308.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
distributed parameter system
hyperbolic system
partial differential equation
transfer function
heat exchanger
układ o parametrach rozłożonych
system hiperboliczny
równanie różniczkowe cząstkowe
funkcja przeniesienia
wymiennik ciepła
Opis:
Results of transfer function analysis for a class of distributed parameter systems described by dissipative hyperbolic partial differential equations defined on a one-dimensional spatial domain are presented. For the case of two boundary inputs, the closed-form expressions for the individual elements of the 2×2 transfer function matrix are derived both in the exponential and in the hyperbolic form, based on the decoupled canonical representation of the system. Some important properties of the transfer functions considered are pointed out based on the existing results of semigroup theory. The influence of the location of the boundary inputs on the transfer function representation is demonstrated. The pole-zero as well as frequency response analyses are also performed. The discussion is illustrated with a practical example of a shell and tube heat exchanger operating in parallel- and countercurrent-flow modes.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2013, 23, 2; 291-307
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Jurdjevic-Quinn theorem for stochastic differential systems under weak conditions
Autorzy:
Florchinger, Patrick
Powiązania:
https://bibliotekanauki.pl/articles/2183489.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
stochastic differential system
weak solution of stochastic differential equation
asymptotic stability in probability
Barbashin–Krasovskii theorem
stabilizing state feedback law
Opis:
The purpose of this paper is to provide sufficient conditions for the stabilizability of weak solutions of stochastic dif- ferential systems when both the drift and diffusion are affine in the control. This result extends the well–known theorem of Jurdjevic–Quinn (Jurdjevic and Quinn, 1978) to stochastic differential systems under weaker conditions on the system coefficients than those assumed in Florchinger (2002).
Źródło:
Control and Cybernetics; 2022, 51, 1; 21--29
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A mathematical model for fluid-glucose-albumin transport in peritoneal dialysis
Autorzy:
Cherniha, R.
Stachowska-Piętka, J.
Waniewski, J.
Powiązania:
https://bibliotekanauki.pl/articles/907934.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
fluid transport
transport in peritoneal dialysis
nonlinear partial differential equations
ordinary differential equation
steady-state solution
transport płynu
dializa otrzewnowa
nieliniowe równanie różniczkowe
równanie różniczkowe zwyczajne
Opis:
A mathematical model for fluid and solute transport in peritoneal dialysis is constructed. The model is based on a three-component nonlinear system of two-dimensional partial differential equations for fluid, glucose and albumin transport with the relevant boundary and initial conditions. Our aim is to model ultrafiltration of water combined with inflow of glucose to the tissue and removal of albumin from the body during dialysis, by finding the spatial distributions of glucose and albumin concentrations as well as hydrostatic pressure. The model is developed in one spatial dimension approximation, and a governing equation for each of the variables is derived from physical principles. Under some assumptions the model can be simplified to obtain exact formulae for spatially non-uniform steady-state solutions. As a result, the exact formulae for fluid fluxes from blood to the tissue and across the tissue are constructed, together with two linear autonomous ODEs for glucose and albumin concentrations in the tissue. The obtained analytical results are checked for their applicability for the description of fluid-glucose-albumin transport during peritoneal dialysis.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2014, 24, 4; 837-851
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A mode-III crack with variable surface effects
Autorzy:
Wang, X.
Schiavone, P.
Powiązania:
https://bibliotekanauki.pl/articles/282009.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
surface elasticity
variable surface moduli
mode-III crack
Cauchy singular integro-differential equation
Opis:
We study the contribution of variable surface effects to the antiplane deformation of a linearly elastic material with a mode-III crack. The surface elasticity is incorporated using a modified version of the continuum based surface/interface model of Gurtin and Murdoch. In our discussion, the surface moduli are not constant but vary along the crack surfaces. Using Green’s function method, the problem is reduced to a single first-order Cauchy singular integro-differential equation, which is solved numerically using Chebyshev polynomials and a collocation method. Our results indicate that the gradient of the surface shear modulus exerts a significant influence on the crack opening displacement and on the singular stress field at the crack tips.
Źródło:
Journal of Theoretical and Applied Mechanics; 2016, 54, 4; 1319-1327
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
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 new analytical procedure for solving the non-linear differential equation arising in the stretching sheet problem
Autorzy:
Siddheshwar, P. G.
Mahabaleswar, U. S.
Andersson, H. I.
Powiązania:
https://bibliotekanauki.pl/articles/266146.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
równania różniczkowe
ciecz Newtona
rozciąganie arkusza
differential equations
Clairaut equation
Newtonian liquid
stretching sheet
suction/injection
Opis:
The paper discusses a new analytical procedure for solving the non-linear boundary layer equation arising in a linear stretching sheet problem involving a Newtonian/non-Newtonian liquid. On using a technique akin to perturbation the problem gives rise to a system of non-linear governing differential equations that are solved exactly. An analytical expression is obtained for the stream function and velocity as a function of the stretching parameters. The Clairaut equation is obtained on consideration of consistency and its solution is shown to be that of the stretching sheet boundary layer equation. The present study throws light on the analytical solution of a class of boundary layer equations arising in the stretching sheet problem.
Źródło:
International Journal of Applied Mechanics and Engineering; 2013, 18, 3; 955-964
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new imaging algorithm for electric capacitance tomography
Nowy algorytm obrazowania w elektrycznej tomografii pojemnościowej
Autorzy:
Pańczyk, M.
Sikora, J.
Powiązania:
https://bibliotekanauki.pl/articles/158998.pdf
Data publikacji:
2016
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Elektrotechniki
Tematy:
electric capacitance tomography
partial differential equations
adjoint equation
inverse problem
elektryczna tomografia pojemnościowa
równania różniczkowe cząstkowe
równanie sprzężone
zagadnienie odwrotne
Opis:
A new imaging algorithm of permittivity for Electrical Capacitance Tomography (ECT) was proposed in this paper. Some aspects of sensitivity analysis and the application of adjoint variables were discussed. In the final section of this paper some advantages and disadvantages were shown.
W pracy przedstawiono „nowy” algorytm obrazowania przenikalności elektrycznej w Elektrycznej Tomografii Pojemnościowej. Omówiono aspekty związane z analizą wrażliwościową i zmienna sprzężoną. Przedstawiono jej interpretację fizyczną. Wskazano na zalety i wady zaproponowanej metody obrazowania.
Źródło:
Prace Instytutu Elektrotechniki; 2016, 274; 27-41
0032-6216
Pojawia się w:
Prace Instytutu Elektrotechniki
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A proposition of a torsional-bending vibrations modelling of combustion engines
Autorzy:
Dąbrowski, Z.
Chiliński, B.
Pankiewicz, J.
Powiązania:
https://bibliotekanauki.pl/articles/244766.pdf
Data publikacji:
2016
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
rotational system
system of differential equation
crankshaft system
numerical solutions
Opis:
The article presents the problem of modelling coupled bending-torsional vibrations in crank systems. Because during the design of modern drive systems a growing number of phenomena are taken into account, model description of such vibrations has a practical meaning. Commonly used models of dynamics of systems assume the independence of torsional and bending vibrations, which leads to simultaneous analysis of transverse and angular vibrations. Further analysis is carried out with the use of superposition principle. Such an approach is justified in the case of quite rigid drive shafts, where vibrations are relatively small. Current trends in the design of reducing weight, reduction of toxic emissions and reducing fuel consumption, lead to the situation where shafts in crank systems become less stiff. Therefore, phenomena neglected earlier may have significant meaning. Analysis of couplings of transverse and torsional vibrations is so important that the occurrence of these phenomena usually leads to new critical states, which may be especially dangerous for engine operation. Considerations on the reasons of the occurrence and kinds of vibration couplings were presented in the introduction of the article. Further part of the article proposes the linear-bending model of the crankshaft, where transverse and angular displacements are dependent. It was tantamount to the assumption of linear relation between the vector of generalized co-ordinates and generalized forces occurring in the system. The next chapter presents the system of equations describing the dynamics of the crankshaft together with a discussion of the co-ordinate system used in the considerations. In addition, there were presented the results of numerical simulations in frequency domain confirming the conclusions taken from the analysis. The whole paper is concluded with synthetic conclusions on the formulated system of equations, simulations and the influence of the coupling on the dynamics of the whole crank system.
Źródło:
Journal of KONES; 2016, 23, 4; 71-77
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A topological version of the Ambrosetti-Prodi theorem
Autorzy:
Przeradzki, Bogdan
Powiązania:
https://bibliotekanauki.pl/articles/1311053.pdf
Data publikacji:
1996
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
multiple solution
resonance
functional-differential equation
Opis:
The existence of at least two solutions for nonlinear equations close to semilinear equations at resonance is obtained by the degree theory methods. The same equations have no solutions if one slightly changes the right-hand side. The abstract result is applied to boundary value problems with specific nonlinearities.
Źródło:
Annales Polonici Mathematici; 1996, 64, 2; 121-130
0066-2216
Pojawia się w:
Annales Polonici Mathematici
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Alien derivatives of the WKB solutions of the gauss hypergeometric differential equation with a large parameter
Autorzy:
Tanda, M.
Powiązania:
https://bibliotekanauki.pl/articles/255675.pdf
Data publikacji:
2015
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
hypergeometric differential equation
WKB solution
Voros coefficient
alien derivative
Stokes curve
fixed singularity
Opis:
We compute alien derivatives of the WKB solutions of the Gauss hypergeometric differential equation with a large parameter and discuss the singularity structures of the Borel transforms of the WKB solution expressed in terms of its alien derivatives.
Źródło:
Opuscula Mathematica; 2015, 35, 5; 803-823
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An adaptive control scheme for hyperbolic partial differential equation system (drilling system) with unknown coefficient
Autorzy:
Farahani, H. S.
Telabi, H. A.
Baghermenhaj, M.
Powiązania:
https://bibliotekanauki.pl/articles/229317.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
drilling systems
adaptive control
hyperbolic partial differential equations
wave equation
boundary control
Opis:
The adaptive boundary stabilization is investigated for a class of systems described by second-order hyperbolic PDEs with unknown coefficient. The proposed control scheme only utilizes measurement on top boundary and assume anti-damping dynamics on the opposite boundary which is the main feature of our work. To cope with the lack of full state measurements, we introduce Riemann variables which allow us reformulate the second-order in time hyperbolic PDE as a system with linear input-delay dynamics. Then, the infinite-dimensional time-delay tools are employed to design the controller. Simulation results which applied on mathematical model of drilling system are given to demonstrate the effectiveness of the proposed control approach.
Źródło:
Archives of Control Sciences; 2017, 27, 1; 63-76
1230-2384
Pojawia się w:
Archives of Control Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł

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