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Wyszukujesz frazę "dynamical system" wg kryterium: Temat


Wyświetlanie 1-7 z 7
Tytuł:
Model based analysis of signaling pathways
Autorzy:
Śmieja, J.
Powiązania:
https://bibliotekanauki.pl/articles/907948.pdf
Data publikacji:
2008
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
ścieżka sygnalizacyjna
układ dynamiczny
biologia systemów
interferon-beta
signaling pathways
dynamical system
systems biology
Opis:
The paper is concerned with application of mathematical modeling to the analysis of signaling pathways. Two issues, deterministic modeling of gene transcription and model-driven discovery of regulatory elements, are dealt with. First, the biological background is given and the importance of the stochastic nature of biological processes is addressed. The assumptions underlying deterministic modeling are presented. Special emphasis is put on describing gene transcription. A framework for including unknown processes activating gene transcription by means of first-order lag elements is introduced and discussed. Then, a particular interferon-ß induced pathway is introduced, limited to early events that precede activation of gene transcription. It is shown how to simplify the system description based on the goals of modeling. Further, a computational analysis is presented, facilitating better understanding of the mechanisms underlying regulation of key components in the pathway. The analysis is illustrated by a comparison of simulation and experimental data.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2008, 18, 2; 139-145
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Time to the convergence of evolution in the space of population states
Autorzy:
Karcz-Dulęba, I.
Powiązania:
https://bibliotekanauki.pl/articles/907643.pdf
Data publikacji:
2004
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
ewolucja fenotypowa
układ dynamiczny
punkt stały
phenotypic evolution
dynamical system
time to convergence
fixed points
Opis:
Phenotypic evolution of two-element populations with proportional selection and normally distributed mutation is considered. Trajectories of the expected location of the population in the space of population states are investigated. The expected location of the population generates a discrete dynamical system. The study of its fixed points, their stability and time to convergence is presented. Fixed points are located in the vicinity of optima and saddles. For large values of the standard deviation of mutation, fixed points become unstable and periodical orbits arise. In this case, fixed points are also moved away from optima. The time to convergence to fixed points depends not only on the mutation rate, but also on the distance of the points from unstability. Results show that a population spends most time wandering slowly towards the optimum with mutation as the main evolution factor.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2004, 14, 3; 279-287
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Procedural generation of aesthetic patterns from dynamics and iteration processes
Autorzy:
Gdawiec, K.
Powiązania:
https://bibliotekanauki.pl/articles/329905.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
dynamical system
dynamics process
iteration process
aesthetic pattern
układ dynamiczny
proces dynamiczny
proces iteracji
wzorzec estetyczny
Opis:
Aesthetic patterns are widely used nowadays, e.g., in jewellery design, carpet design, as textures and patterns on wallpapers, etc. Most of the work during the design stage is carried out by a designer manually. Therefore, it is highly useful to develop methods for aesthetic pattern generation. In this paper, we present methods for generating aesthetic patterns using the dynamics of a discrete dynamical system. The presented methods are based on the use of various iteration processes from fixed point theory (Mann, S, Noor, etc.) and the application of an affine combination of these iterations. Moreover, we propose new convergence tests that enrich the obtained patterns. The proposed methods generate patterns in a procedural way and can be easily implemented on the GPU. The presented examples show that using the proposed methods we are able to obtain a variety of interesting patterns. Moreover, the numerical examples show that the use of the GPU implementation with shaders allows the generation of patterns in real time and the speed-up (compared with a CPU implementation) ranges from about 1000 to 2500 times.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2017, 27, 4; 827-837
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An unconditionally stable nonstandard finite difference method applied to a mathematical model of HIV infection
Autorzy:
Obaid, H. A.
Ouifki, R.
Patidar, K. C.
Powiązania:
https://bibliotekanauki.pl/articles/331053.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
HIV infection
dynamical system
nonstandard finite difference methods
equilibria
stability
zakażenie HIV
układ dynamiczny
metoda różnic skończonych
równowaga
Opis:
We formulate and analyze an unconditionally stable nonstandard finite difference method for a mathematical model of HIV transmission dynamics. The dynamics of this model are studied using the qualitative theory of dynamical systems. These qualitative features of the continuous model are preserved by the numerical method that we propose in this paper. This method also preserves the positivity of the solution, which is one of the essential requirements when modeling epidemic diseases. Robust numerical results confirming theoretical investigations are provided. Comparisons are also made with the other conventional approaches that are routinely used for such problems.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2013, 23, 2; 357-372
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Generalized practical stability analysis of discontinuous dynamical systems
Autorzy:
Zhai, G.
Michel, A. N.
Powiązania:
https://bibliotekanauki.pl/articles/907305.pdf
Data publikacji:
2004
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
układ dynamiczny nieciągły
analiza ilościowa
funkcja Lyapunova
discontinuous dynamical system
quantitative analysis
generalized practical stability
Lyapunov-like function
Opis:
In practice, one is not only interested in the qualitative characterizations provided by the Lyapunov stability, but also in quantitative information concerning the system behavior, including estimates of trajectory bounds, possibly over finite time intervals. This type of information has been ascertained in the past in a systematic manner using the concept of practical stability. In the present paper, we give a new definition of generalized practical stability (abbreviated as GP-stability) and establish some sufficient conditions concerning GP-stability for a wide class of discontinuous dynamical systems. As in the classical Lyapunov theory, our results constitute a Direct Method, making use of auxiliary scalar-valued Lyapunov-like functions. These functions, however, have properties that differ significantly from the usual Lyapunov functions. We demonstrate the applicability of our results by means of several specific examples.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2004, 14, 1; 5-12
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On a stable solution of the problem of disturbance reduction
Autorzy:
Maksimov, Vyacheslav I.
Powiązania:
https://bibliotekanauki.pl/articles/1838215.pdf
Data publikacji:
2021
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
disturbance reduction
dynamical controlled system
guaranteed control theory
redukcja zakłóceń
system sterowany dynamicznie
teoria sterowania
Opis:
We study the problem of active reduction of the influence of a disturbance on the output of a linear control system. We consider a system of linear differential equations under the action of an unknown disturbance and a control to be formed. Our goal is to design an algorithm for reducing the disturbance by means of an appropriate control on the basis of inaccurate measurements of the system phase coordinates. This algorithm should form a feedback control that would guarantee that the trajectory of a given system tracks the trajectory of the reference system, i.e., the system described by the same differential equations but with zero control and disturbance. We present an algorithm for solving this problem. The algorithm, based on the constructions of guaranteed control theory, is stable with respect to informational noises and computational errors.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2021, 31, 2; 187-194
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Derivation of physically motivated constraints for efficient interval simulations applied to the analysis of uncertain dynamical systems
Autorzy:
Freihold, M.
Hofer, E. P.
Powiązania:
https://bibliotekanauki.pl/articles/930126.pdf
Data publikacji:
2009
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
system Hamiltona
algorytm rozgałęzienia
system dynamiczny
VALENCIA-IVP
consistency tests for the reduction of overestimation
identification of dynamical constraints
Hamiltonian systems
branch algorithm
prune algorithm
Opis:
Interval arithmetic techniques such as VALENCIA-IVP allow calculating guaranteed enclosures of all reachable states of continuous-time dynamical systems with bounded uncertainties of both initial conditions and system parameters. Considering the fact that, in naive implementations of interval algorithms, overestimation might lead to unnecessarily conservative results, suitable consistency tests are essential to obtain the tightest possible enclosures. In this contribution, a general framework for the use of constraints based on physically motivated conservation properties is presented. The use of these constraints in verified simulations of dynamical systems provides a computationally efficient procedure which restricts the state enclosures to regions that are physically eaningful. A branch and prune algorithm is modified to a consistency test, which is based on these constraints. Two application scenarios are studied in detail. First, the total energy is employed as a conservation property for the analysis of mechanical systems. It is shown that conservation properties, such as the energy, are applicable to any Hamiltonian system. The second scenario is based on constraints that are derived from decoupling properties, which are considered for a high-dimensional compartment model of granulopoiesis in human blood cell dynamics.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2009, 19, 3; 485-499
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-7 z 7

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