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Axial magnetic bearing as a passive vibration damper
Polák, Robert ; Marada, Tomáš (referee) ; Pruša, Radomír (advisor)
The aim of the bachelor thesis is to design a mathematical model describing the damping effects of a prototype passive axial magnetic bearing. The prototype consists of three permanent axial magnets, the two outer ones are stators and are connected to the base, the middle magnet works as a rotor. Part of the work was a research on the topic of vibration dampers and their mathematical models. An experimental measurement of the dependence of the response of the axial deflection of the rotor on the axial load of the shaft was performed on a prototype bearing. The approach to creating a mathematical model was divided into two parts. First, the geometry of the bearing was simulated using the finite element method programme FEMM and the dependence of the force acting on the rotor magnet as a function of its deflection was determined. In the second part, the permanent magnets were replaced by conductive loops, for which the dependence of the magnitude of the power dissipation on their mutual deflection was compiled by the gradual derivation from the known equations. By connecting these two parts, an equation of motion was created for the middle loop or magnet. Using the Matlab and Simulink programs, this equation was simulated and then the results were compared with experimental measurements. Finally, the measurement and suitability of the mathematical model were evaluated.
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Any-angle path planning
Polák, Robert ; Šoustek, Petr (referee) ; Dvořák, Jiří (advisor)
The final thesis deals with the issue of any-angle path planning. The theoretical part of the thesis is focused on the description of the general issue of path planning, on the description of existing methods of its search, and above all on the characteristics of any-angle planning methods. In addition to the assignment, a new algorithm for any-angle search was created. In the practical part, selected algorithms were implemented and then comparative experiments were performed.
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Comparison of advantages and disadvantages OOP databases against relational databases
Polák, Robert ; Jirků, Petr (advisor) ; Duží, Marie (referee)
There exists different approaches on database modeling. This work tries to identify strengths and weaknesses of nowadays technologies. Besides relational databases, object oriented databases, and methods to combine the world of objects with the world of tables of relational databases. Last part gives attention to design of methodology of process of development of information systems using technology that implements object access to the data throw build on relational database facilities .
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Axial magnetic bearing as a passive vibration damper
Polák, Robert ; Marada, Tomáš (referee) ; Pruša, Radomír (advisor)
The aim of the bachelor thesis is to design a mathematical model describing the damping effects of a prototype passive axial magnetic bearing. The prototype consists of three permanent axial magnets, the two outer ones are stators and are connected to the base, the middle magnet works as a rotor. Part of the work was a research on the topic of vibration dampers and their mathematical models. An experimental measurement of the dependence of the response of the axial deflection of the rotor on the axial load of the shaft was performed on a prototype bearing. The approach to creating a mathematical model was divided into two parts. First, the geometry of the bearing was simulated using the finite element method programme FEMM and the dependence of the force acting on the rotor magnet as a function of its deflection was determined. In the second part, the permanent magnets were replaced by conductive loops, for which the dependence of the magnitude of the power dissipation on their mutual deflection was compiled by the gradual derivation from the known equations. By connecting these two parts, an equation of motion was created for the middle loop or magnet. Using the Matlab and Simulink programs, this equation was simulated and then the results were compared with experimental measurements. Finally, the measurement and suitability of the mathematical model were evaluated.
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Comparison of advantages and disadvantages OOP databases against relational databases
Polák, Robert ; Duží, Marie (referee) ; Jirků, Petr (advisor)
There exists different approaches on database modeling. This work tries to identify strengths and weaknesses of nowadays technologies. Besides relational databases, object oriented databases, and methods to combine the world of objects with the world of tables of relational databases. Last part gives attention to design of methodology of process of development of information systems using technology that implements object access to the data throw build on relational database facilities .
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Abuse of ecstasy in South Bohemia region and possibilities of prevention
POLÁK, Robert
Ecstasy, MDMA (3,4-methylendioxymetamfetamin) is a synthetic, psychoactive substance, chemically similar to stimulant methamphetamine and hallucinogenic mescaline. MDMA is active primarily on neurons in the brain. For the communication with other neurons, neurons are using serotonin. Serotonin system plays a significant role in regulation of mood, aggressiveness, sleep and pain sensitivity. In high dosage MDMA disturbs the ability of the body to regulate body temperature. This may lead to fast increase in body temperature (hyperthermia). Ecstasy is generally considered to be a rather safe drug, although a number of physical as well as psychiatrical consecutive health problems have occurred. Specific mechanisms of MDMA toxicity have still not been fully clarified; however, it is obvious that these cannot be attributed only to MDMA over dosage or the use of impure tablets (i.e. e. toxicity cannot be ascribed plainly to admixture in tablets).
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Nové technologie firmy Microsoft pro vytváření uživatelského rozhraní
Kovařík, Milan ; Buchalcevová, Alena (advisor) ; Polák, Robert (referee)
V této práci je představena technologie pro tvorbu moderního grafického uživatelského rozhraní Windows Presentation Foundation (WPF) z dílny firmy Microsoft. V prvních kapitolách práce je vysvětlen pojem uživatelského rozhraní a jeho historie na platformě Microsoft Windows, dále pak technologie, které jsou součástí rodiny .NET frameworku 3.0 a teoretická koncepce WPF. Cílem práce je poskytnout ucelený návod jak vytvářet aplikace ve WPF. Návod by měl umožnit zájemcům snadný vstup do WPF problematiky.Jednotlivé kroky návodu jsou vysvětleny na praktickém příkladu.
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