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Dynamic model of nonlinear oscillator with piezoelectric layer
Sosna, Petr ; Lošák, Petr (referee) ; Hadaš, Zdeněk (advisor)
Tato diplomová práce je zaměřena na analýzu chování magnetopiezoelastického kmitajícího nosníku. V teoretické části jsou odvozeny diskretizované parametry, které popisují reálnou soustavu jako model s jedním stupněm volnosti. Tento model je následně použit pro kvalitativní i kvantitativní analýzu chování tohoto harvesteru. Frekvenční odezva harmonicky buzeného systému je zkoumána v dvouparametrické nebo tříparametrické analýze v závislosti na amplitudě buzení, elektrické zátěži a vzdálenosti mezi magnety. Posledně zmíněný parametr je v práci tím hlavním, proto je vliv vzdálenosti magnetů zkoumán také s pomocí bifurkačních diagramů. Tyto diagramy byly navíc použity k vytvoření oscilační "mapy", která pro každé zatěžovací podmínky ukazuje, jakou vzdálenost magnetů je třeba nastavit, aby bylo generováno nejvíce energie. Práce je doplněna o ukázky několika jevů, které mohou značně ovlivnit chování systému, pokud se nejdená o čistě harmonické buzení.
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Bifurcations in a chaotic dynamical system
Kateregga, George William ; Tomášek, Petr (referee) ; Nechvátal, Luděk (advisor)
Dynamical systems possess an interesting and complex behaviour that have attracted a number of researchers across different fields, such as Biology, Economics and most importantly in Engineering. The complex and unpredictability of nonlinear customary behaviour or the chaotic behaviour, makes it strange to analyse them. This thesis presents the analysis of the system of nonlinear differential equations of the so--called Lu--Chen--Cheng system. The system has similar dynamical behaviour with the famous Lorenz system. The nature of equilibrium points and stability of the system is presented in the thesis. Examples of chaotic dynamical systems are presented in the theory. The thesis shows the dynamical structure of the Lu--Chen--Cheng system depending on the particular values of the system parameters and routes to chaos. This is done by both the qualitative and numerical techniques. The bifurcation diagrams of the Lu--Chen--Cheng system that indicate limit cycles and chaos as one parameter is varied are shown with the help of the largest Lyapunov exponent, which also confirms chaos in the system. It is found out that most of the system's equilibria are unstable especially for positive values of the parameters $a, b$. It is observed that the system is highly sensitive to initial conditions. This study is very important because, it supports the previous findings on chaotic behaviours of different dynamical systems.
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Fractals in Computer Graphics
Šelepa, Jan ; Venera, Jiří (referee) ; Sumec, Stanislav (advisor)
The goal of this work is to give introduction and specification of fractals. The first chapter presents the basics of fractal geometry. The second chapter maps the history of fractals and points out the most important people of fractal science. The third chapter presents fractal classification based on several criteria and gives basic examples. The fourth chapter is a summary of widely used applications for fractal creation. The last chapter describes the application that was made to demonstrate given algorithms and fractals mentioned in this thesis.
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Automatic Photo Sorting
Weiser, Michal ; Španěl, Michal (referee) ; Beran, Vítězslav (advisor)
The purpose of this article is to show how intuitive can be work with pictures sorting. Drag&drop technology in combination with interactive picture moving makes this application easy to use. To sort pictures with some feature you just must drag magnetic attractor into some place in workspace and choose attracting feature with specific value. Pictures with alike value are attracted. Difference in values determines the distance between picture and attractor. Combination of many attractors can help you sort pictures in short time with just couple of clicks.
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Equivalent circuit realizations of the simple chaotic oscillators
Kobza, Jaromír ; Dostál, Tomáš (referee) ; Petržela, Jiří (advisor)
The aim of this paper is to introduce with basic theory the problems encountered when considering the circuit implementation of autonomous RC chaotic oscillator with nonlinearity. All oscillator prototypes are based on one type of universal oscillator circuit. This circuit is able to generate a lot of attractors on condition of different entrance parameters. The design is based on a mathematical simulation, which includes the generation of electronic circuit values. The work is focused the transformation of these values to operational circuit configuration and simulation in a circuit simulator. The final task is to acquire chaotic attractors. Oscilloscope and spectrum analyser photos will verify the operation.
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Attractors in the complex dynamics of turbulent convection
Kašný, Jakub ; Nechvátal, Luděk (referee) ; Macek, Michal (advisor)
This Bachelor's thesis deals with an application of the HAVOK (Hankel Alternative View of Koopman) numerical method, which seeks attractors and predicts intermittent phenomena in dynamical systems, to data from Rayleigh-Bénard convection (RBC), which are measured at Brno Institute of Scientific Instruments in the group of Cryogenics and Superconductivity. This thesis discusses the theory on which the HAVOK is built and further deepens it compared to the article [2]. Furthermore, it enlightens some issues as the best selection of the embedding dimension r, which we selected based on the quality of regression that HAVOK creates, or the use of the Koopman operator and Taken's embedding theorem, that weren't explicitly explained in the article [2]. We discovered three different methods to compute HAVOK regressions based on and using the codes attached to the article. In the thesis, we inspect the matrices of ordinary differential equations, their behaviour when the initial values are changed and their stability for the different regression models and embedding dimensions. The solution with different initial conditions is plotted so that the attractivity can be seen. Part of the thesis contains description of RBC, its equations of motion and characteristic dimensionless numbers that describe the convection. Moreover, the thesis describes how the data are obtained and processed normally and how are processed in new ways based on the HAVOK method.
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The Control of Chaos: Methods and Applications
Hůlka, Tomáš ; Dvořák, Jiří (referee) ; Matoušek, Radomil (advisor)
This thesis focuses on deterministic chaos and selected methods of chaos control. It briefly describes the matter of deterministic chaos and presents commonly used tools of analysis of dynamical systems exhibiting chaotic behavior. A list of frequently studied chaotic systems is presented and followed by a description of methods of chaos control and the optimization of these methods. The practical part is dedicated to the stabilization of two model systems and one real system with described methods.
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