
WE43 BIOCOMPATIBLE ALLOY AFTER SEVERE PLASTIC DEFORMATION: STRUCTURE CHARACTERIZATION
Kunčická, Lenka ; Král, Petr ; Dvořák, Jiří ; Kocich, R.
The report presents results of the analyses of biocompatible WE 43 Mgbased alloy processed by friction stir processing (FSP) at two different rotational speeds of 400 RPM, and 1200 RPM. The structures were observed by scanning electron microscopy (SEM), electron backscattered diffraction (EBSD). Observations were primarily focused on characterizations of grains and textures, supplementary testing of mechanical properties was performed via tensile tests. The results of low angle grain boundaries fractions and grain sizes showed that both the processing methods led to significant grain refinement and recrystallization, the average grain diameter within the 1200 RPM sample was less than 2 μm. Texture observations showed slight tendencies of the grains to align in the {0001}〈101̅0〉 and {0001}〈112̅0〉 preferential orientations, however, the maximum intensities were only about two times random. Supplementary tensile tests confirmed the positive effects of FSP on structures and properties of both the samples.


Estimation of the pair correlation function of a point process
Vondráček, Jakub ; Dvořák, Jiří (advisor) ; Beneš, Viktor (referee)
This thesis deals with kernel estimation of the pair correlation function of a stationary and isotropic point process. Firstly, the basics of the theory of point processes are built up. Then, the derivation of formulas for expectation and variance of a kernel estimator is provided. Also, an extension of a simple Poisson approximation of variance to the case of an estimator with more complicated edge correction compared to what is usually used in the literature is given. These formulas depend on a parameter called bandwidth. The recommendations for selecting the bandwidth that can be found in the literature are summarised and simulation experiments are performed to assess the correctness of the derived formulas. These experiments also prove that a variance approximation obtained by ignoring so called "higher order correlations" is unjustified. Lastly, bandwidth selection and the advantages and disadvantages of several approaches for bandwidth selection are discussed. 1


Measures of dependence
Matoušková, Monika ; Pawlas, Zbyněk (advisor) ; Dvořák, Jiří (referee)
The most common measure of dependence is the correlation coefficient. Its problem is that it can be zero for two dependent random variables. We will discuss two measures of dependence, which are equal to zero if and only if the two random variables are inde pendent. We will compare them with Pearson's correlation coefficient. The first one will be the maximal correlation, which is often difficult to calculate. That is why we define the maximal polynomial correlation, which is easier to calculate and is nondecreasing in a degree of a polynomial. We also define the distance correlation and we discuss other ways of the expression of distance correlation, which can be used in the calculation. We deal with the case of normal distribution and we show some calculations of these measures of dependence. 1


Separability of the intensity function of a Poisson point process
Petráková, Martina ; Dvořák, Jiří (advisor) ; Prokešová, Michaela (referee)
Our main interest in the thesis is Poisson point process and one of its charac teristics  intensity function. Whenever Poisson process has intensity function, its distribution is uniquely determined by it. Our main goal is to determine how to deduce from observed data whether intensity function is separable. We present a formal test of this hypothesis assuming exponential model of the in tensity function depending on finite number of parameters. Properties of this test are then examined in a simulation study. 1


Synthetic Fingerprint Generation Using GAN
Dvořák, Jiří ; Drahanský, Martin (referee) ; Kanich, Ondřej (advisor)
Tato bakalářská práce se zabývá generováním syntetických otisků prstů za pomoci modelu založeném na principu generativních soupeřících sítí. Práce shrnuje základní teoretické informace z biometrie se zaměřením na otisky prstů. Zaobírá se také principem jednoho z populárních generátorů syntetických otisků prstů  nástrojem SFinGe. Práce představuje model postavený na hluboké konvoluční generativní soupeřící síti a představuje několik metod, které vedly ke zlepšení jeho výkonu. Vyhodnocení výsledků bylo provedeno výpočtem "Fréchet Inception Distance mezi vygenerovanými a existujími otisky. Dále byl vygenerován dataset obsahující 100 snímků. Ten byl vyhodnocen nástrojem NFIQ 2.0, který ukázal, že model je schopný generovat otisky prstů kvality srovnatelné s reálnými trénovacími daty.

 

Path planning for multiple robots
Sekáč, Ondřej ; Šoustek, Petr (referee) ; Dvořák, Jiří (advisor)
This master thesis deals with path planning for multiple mobile robots. The theoretical part describes robot navigation  mapping and path planning. Selected methods of artificial intelligence used in multirobot path planning are described. In practical part simulator is implemented, in which selected algorithms were compared using experiments.


Advanced methods of mobile robot path planning
Maňáková, Lenka ; Šoustek, Petr (referee) ; Dvořák, Jiří (advisor)
This work is focused on advanced methods of mobile robot's path planning. The theoretical part describes selected graphical methods, which are useful for speeding up the process of finding the shortest paths, for example through reduction of explored nodes of the state space. In the practical part was created simulate environment in the Python language and in this environment, selected algorithms was implemented.

 

Mobile robot path planning by means of cellular automata
Holoubek, Tomáš ; Šoustek, Petr (referee) ; Dvořák, Jiří (advisor)
This thesis deals with a path planning using cellular automata algorithms in a rectangular grid environment. Theoretical part starts with an overview of commonly used approaches for path planning and later on focuses on existing cellular automata solutions and capabilities in detail. Implemented cellular automata algorithms and the commonly used path planning algorithms are together with a map generator described in the practical part. Conclusion of this thesis contains results completed in a special application.
