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Existence and Properties of Global Solutions of Mixed-Type Functional Differential Equations
Vážanová, Gabriela ; Růžičková, Miroslava (oponent) ; Fečkan,, Michal (oponent) ; Diblík, Josef (vedoucí práce)
This thesis focuses on functional differential equations of mixed type also referred to as advance-delay equations. It gives sufficient conditions for the existence of global and semi-global solutions to nonlinear mixed differential systems. The methods used in this thesis consist of building suitable operators for differential equations and proving the existence of their fixed points. These fixed points are then used to construct the solutions of advance-delay equations. The monotone iterative method and Schauder-Tychonoff fixed point theorems are used in the proofs. In both cases, we also provide solution estimates. Moreover, with the monotone iterative method, these estimates may be improved by iterations. In addition, criteria for linear equations and systems are derived and series of examples are provided. The results obtained are also applicable to ordinary, delayed or advanced differential equations.
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Stochastic Calculus and Its Applications in Biomedical Practice
Klimešová, Marie ; Růžičková, Miroslava (oponent) ; Dzhalladova, Irada (oponent) ; Baštinec, Jaromír (vedoucí práce)
In the presented dissertation is defined the stochastic differential equation and its basic properties are listed. Stochastic differential equations are used to describe physical phenomena, which are also influenced by random effects. Solution of the stochastic model is a random process. Objective of the analysis of random processes is the construction of an appropriate model, which allows understanding the mechanisms. On their basis observed data are generated. Knowledge of the model also allows forecasting the future and it is possible to control and optimize the activity of the applicable system. In this dissertation is at first defined probability space and Wiener process. On this basis is defined the stochastic differential equation and the basic properties are indicated. The final part contains biology model illustrating the use of the stochastic differential equations in practice.
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Optimization of Delayed Differential Systems by Lyapunov's Direct Method
Demchenko, Hanna ; Růžičková, Miroslava (oponent) ; Shatyrko,, Andriy (oponent) ; Diblík, Josef (vedoucí práce)
The present thesis deals with processes controlled by systems of delayed differential equations $$x'(t) =f(t,x_t,u),\,\,\,\, t\ge t_{0}$$ where $t_0 \in \mathbb{R}$, $f$ is defined on a subspace of $[t_0,\infty)\times {C}_{\tau}^{m}\times {\mathbb{R}}^r$, $m,r \in \mathbb{N}$, ${C}_{\tau}^{m}=C([-\tau,0],{\mathbb{R}}^{m})$, $\tau>0$, $x_t(\theta):=x(t+\theta)$, $\theta\in[-\tau,0]$, $x\colon [t_0-\tau,\infty)\to \mathbb{R}^{m}$. Under the assumption $f(t,\theta_m^*,\theta_r)=\theta_m$, where ${\theta}_m^*\in {C}_{\tau}^{m}$ is a zero vector-function, $\theta_r$ and $\theta_m$ are $r$ and $m$-dimensional zero vectors, a control function $u=u(t,x_t)$, $u\colon[t_0,\infty)\times {C}_{\tau}^{m}\to \mathbb{R}^{r}$, $u(t,{\theta}_m^*)=\theta_r$ is determined such that the zero solution $x(t)=\theta_m$, $t\ge t_{0}-\tau$ of the system is asymptotically stable and, for an arbitrary solution $x=x(t)$, the integral $$\int _{t_{0}}^{\infty}\omega \left(t,x_t,u(t,x_t)\right)\diff t,$$ where $\omega$ is a positive-definite functional, exists and attains its minimum value in a given sense. To solve this problem, Malkin's approach to ordinary differential systems is extended to delayed functional differential equations and Lyapunov's second method is applied. The results are illustrated by examples and applied to some classes of delayed linear differential equations.
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Weakly Delayed Systems of Linear Discrete Equations in R^3
Šafařík, Jan ; Khusainov, Denys (oponent) ; Růžičková, Miroslava (oponent) ; Diblík, Josef (vedoucí práce)
The present thesis deals with the construction of a general solution of weakly delayed systems of linear discrete equations in ${\mathbb R}^3$ of the form \begin{equation*} x(k+1)=Ax(k)+Bx(k-m) \end{equation*} where $m>0$ is a positive integer, $x\colon \bZ_{-m}^{\infty}\to\bR^3$, $\bZ_{-m}^{\infty} := \{-m, -m+1, \dots, \infty\}$, $k\in\bZ_0^{\infty}$, $A=(a_{ij})$ and $B=(b_{ij})$ are constant $3\times 3$ matrices. The characteristic equations of weakly delayed systems are identical with those of the same systems but without delayed terms. The criteria ensuring that a system is weakly delayed are developed and then specified for every possible case of the Jordan form of matrix $A$. The system is solved by transforming it into a higher-dimensional system but without delays \begin{equation*} y(k+1)=\mathcal{A}y(k), \end{equation*} where ${\mathrm{dim}}\ y = 3(m+1)$. Using methods of linear algebra, it is possible to find the Jordan forms of $\mathcal{A}$ depending on the eigenvalues of matrices $A$ and $B$. Therefore, general the solution of the new system can be found and, consequently, the general solution of the initial system deduced.
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Porovnání institutů náhradní rodinné péče z hlediska potřeb dítěte a pečujících osob
Růžičková, Miroslava ; Křížová, Eva (vedoucí práce) ; Janečková, Hana (oponent)
Diplomová práce s názvem: "Porovnání institutů náhradní rodinné péče z hlediska potřeb dítěte i pečujících osob" se zaměřuje především na problematiku pěstounské péče a péče jiné fyzické osoby než rodiče z pohledu potřeb dětí i pečujících osob. V praxi se jedná o dva nápadně podobné instituty, které mají má specifika. Cílem mé diplomové práce je popsat, vysvětlit a konkretizovat rozdílnosti těchto institutů a přiblížit, jak je nahlížejí pečující osoby. Za specifika dlouhodobé pěstounské péče a péče jiné fyzické osoby je v diplomové práci považován zejména způsob hmotného zabezpečení státu, způsob spolupráce s neziskovým sektorem, právní úprava institutů, zkušenosti pečující osoby a problematika spolupráce s původní rodinou. V empirické části byl proveden kvantitativní výzkum prostřednictvím dotazníkového šetření, který se zaměřil na zkušenosti a znalosti pečujících osob. Práce se rovněž zabývá kvantitativním výzkumem, kdy pečující osoby sdělují své názory a zkušenosti. Hlavním zjištěním je, že osoby, pečující v institutu pěstounské péče, mají větší znalosti o nových právech a povinnostech vyplývajících z novely Zákona o sociálně-právní ochraně dětí. Zároveň pečující osoby z institutu pěstounské péče nejsou seznámeny s rozdíly institutů náhradní rodinné péče častěji, než v institutu jiné fyzické osoby než...
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Representation of Solutions of Linear Discrete Systems with Delay
Morávková, Blanka ; Růžičková, Miroslava (oponent) ; Khusainov, Denys (oponent) ; Diblík, Josef (vedoucí práce)
The dissertation thesis is concerned with linear discrete systems with constant matrices of linear terms with a single or two delays. The main objective is to obtain formulas analytically describing exact solutions of initial Cauchy problems. To this end, some matrix special functions called discrete matrix delayed exponentials are defined and used. Their basic properties are proved. Such special matrix functions are used to derive analytical formulas representing the solutions of initial Cauchy problems. First is discussed the initial problem with impulses are acting at some prescribed points and formulas describing the solutions of this problem are derived. In the next part of the dissertation, two definitions of discrete matrix delayed exponentials for two delays are given and their basic properties are proved. Such discrete special matrix functions make it possible to find representations of solutions of linear systems with two delays. This is done in the last part of dissertation thesis where two different formulas giving the analytical solution of this problem are derived.
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