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Laboratory current source with direct digital synthesis
Pěčonka, David ; Hejtmánek, Tomáš (referee) ; Mikulka, Jan (advisor)
The work deals with the design of a laboratory generator with a current output for supplying elements with a maximum impedance in units of k. The text itself discusses the designs of individual parts of the device and the choice of suitable components for their implementation. The sub-chapters deal with the design process of the power supply and digital parts are followed by the mechanical construction of the source, which ends with the verification of the expected properties of the designed and constructed source. The result of the work is a source with a current output of up to ±10 mA with the possibility of parameterization of the frequency, amplitude and shape of the signal using control elements and also digitally using the universal serial bus. The signal is generated using a direct digital synthesis (DDS) system. The generator itself is supplied by a rechargeable battery.
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Communication infrastructure for drone swarm
Kubant, Michal ; Mikulka, Jan (referee) ; Janoušek, Jiří (advisor)
This thesis deals with creation and testing of wireless communication network used for transmission of multimedia and telemetry data in swarm of unmanned aerial vehicles. In the first part of this work are presented functions of the IEEE 802.11ax and their possible usage. The second part if thesis describes configuration of network elements in the wireless network, and discusses maximum transmission speed. The third part presents testing of the assembled network, designs and use of protocols for multimedia streams in a swarm of drones. Also the results are briefly evaluated and illustrated. The fourth part analyzes the methodology of testing the network in the outdoor environment, it discusses the results obtained by using this methodology in different outdoor spaces, and further proposes suitable solutions for improving the efficiency and range of the wireless network.
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High-order stochastic dominance
Mikulka, Jakub ; Kopa, Miloš (advisor) ; Branda, Martin (referee)
The thesis deals with high-order stochastic dominance of random variables and portfolios. The summary of findings about high-order stochastic dominance and portfolio efficiency is presented. As a main part of the thesis it is proven that under assumption of both normal and gamma distribution the infinite-order stochastic dominance is equivalent to the second-order stochastic dominance. The necessary and sufficient condition for the infinite-order stochastic dominance portfolio efficiency is derived under the assumption of normality. The condition is used in the empirical part of the thesis where parametrical approach to the portfolio efficiency is compared to the nonparametric scenario approach. The derived necessary and sufficient condition is based on the assumption of normality; therefore we use two sets of data, one with fulfilled assumption of normality and the other for which the assumption of normality was unambigously rejected. Consequently, the influence of fulfillment of the normality assumption on the results of the necessary and sufficient condition for portfolio efficiency is estimated.
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Exponential smoothing
Mikulka, Jakub ; Hanzák, Tomáš (advisor) ; Cipra, Tomáš (referee)
Nazev prace: Exponencialnivyrovnavani Autor: Jakub Mikulka Katedra: Katedra pravdepodobnosti a matematicke statistiky Vedouci bakalarske prace: Mgr. Tomas Hanzak e-mail vedouciho:hanzak@karlin.mff.cuni.cz Abstrakt: Prace se zabyva dvema metodami exponencialniho vyrovnavani pro nesezonni casove rady s lokalne linearnim trendem: Holtove metode a dvojitemu exponencialmmu vyrovnani (Brownove metode). Je ukazano, ze Brownova metoda je specialnim pnpadem Holtovy metody. Dale je uveden vztah procesu ARIMA(0, 2, 2) a Holtovy metody. Hlavni casti prace je teoreticke odvozeni hodnoty MSE a autokorelacniho koeficientu pfedpovedmch chyb Q pri pouziti Holtovy metody pro vsechny kombinace jejfch vyrovnavacich konstant za predpokladu generovani rady procesem ARIMA(0, 2, 2} pro vsechny hodnoty jeho parametru. Odvozene teoreticke vzorce jsou aplikovany tez na Brownovu metodu. Odvozene vzorce jsou pomoci simulaci overeny a vyzkouseny na realnych casovych radach. Jsou formulovany prakticke zavery tykajici se obou metod. Klicova slova: autokorelacni koeficient predpovednich chyb, Holtova metoda, dvojite exponencialni vyrovnavani,MSE, vyrovnavaci konstanty Abstract Title: Exponential smoothing Author: Jakub Mikulka Department: Department of Probability and Mathematical Statistics Supervisor: Mgr. Tomas Hanzak...
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Optimizing Image Reconstruction in Electrical Impedance Tomography
Dušek, Jan ; Brančík, Lubomír (referee) ; Sikora, inž Jan (referee) ; Mikulka, Jan (advisor)
Tato disertační práce pojednává o optimalizaci algoritmů pro rekonstrukci obrazu neznámé měrné vodivosti z měřených dat pořízených elektrickou impedanční tomografií. Danou problematiku zde věcně vymezuje několik různých prvků, zejména pak stručný matematický popis dopředné a inverzní úlohy řešené různými přístupy, metodika měření a pořizování dat pro rekonstrukci a přehled dostupných numerických nástrojů. Uvedenou charakteristiku rozšiřuje rozbor optimalizací parametrů modelu ovlivňujících přesnost rekonstrukce, způsoby paralelního zpracování algoritmů a souhrn dostupných zařízení pro měření tomografických dat. Na základě získaných poznatků byla navržena optimalizace parametrů matematického modelu, která umožňuje jeho velmi přesný návrh dle měřených dat. V této souvislosti dochází ke snížení nejistoty rekonstrukce rozložení konduktivity. Pro zefektivnění procesu získávání dat bylo navrženo zařízení k automatizaci tomografie s důrazem na cenovou dostupnost a snížení nejistoty měření. V oblasti tvorby numerického modelu byly dále zkoumány možnosti užití otevřených a uzavřených domén pro různé metody regularizace a hrubost sítě, a to s ohledem na velikost chyby rekonstruované konduktivity a výpočetní náročnost. Součástí práce je také paralelizace subalgoritmů rekonstrukce s využitím vícejádrové grafické karty. Předložené výsledky mají přímý vliv na snížení nejistoty rekonstrukce (optimalizací počáteční hodnoty konduktivity, rozmístění elektrod a tvarové deformace domény, regularizačních metod a typu domén) a urychlení výpočtů paralelizací algoritmů, přičemž výzkum byl podpořen vlastním návrhem jednotky pro automatizaci tomografie.
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Virtual measuring instruments to support the education
Bilík, Petr ; Marcoň, Petr (referee) ; Mikulka, Jan (advisor)
This diploma thesis deals with the creation of the Virtual Measuring Instruments web application. This tool mainly enables us to simulate the real measuring instruments widely used in the laboratories of FEEC BUT. It is intended to serve students for initial acquaintance with specific devices. The theoretical part is focused on the research into the web applications programming and suitable programming languages to implement the proposed application are selected. Furthermore, the specific virtualized devices are described. The result of the experimental part consists in creating a universal application interface to extend the proposed application with other devices. Finally, the specific tests of the developed platform are presented.
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Precise segmentation of image data
Svoboda, Jan ; Marcoň, Petr (referee) ; Mikulka, Jan (advisor)
The concern of this thesis is a development of an extension module for 3D Slicer platform. The core of the module is an implementation of a Support Vector Machines classifier, which is used for segmentation of the vertebral column image data provided by the University Hospital Brno. One of the goals of the thesis was resampling and registration of these image sequences. CT volumes provided solid contrast and were used as a reference for gaining properly segmented groups of vertebrae. Due to the low quality of the MRI volumes image data, segmentation of MRI images was not completely succesful. The extension module scripted in Python language can be seen as a tool and can be used in the future for different datasets.
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Portable digitally controlled stabilized source of symmetrical voltage
Hynek, David ; Drexler, Petr (referee) ; Mikulka, Jan (advisor)
This thesis deals with a design of a power supply for a measuring equipment for a geophysical mapping intended to do a reconstruction of an electrical impedance of a ground environment of water reservoirs. The power source is going to be used for laboratory measurements and for outdoor experiments. The thesis describes the selection of suitable components, equipment design and testing. The theoretical part explains the functions of used components and the principle of an electrical impedance tomography. The conclusion summarizes the properties of the proposed solution and evaluates the final product.
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DESIGN OF FIBER-OPTIC BIOSENSOR WITH NEAR-INFRARED SPECTRAL ANALYSIS
Křepelka, Pavel ; Jakubec,, Martin (referee) ; Skládal, Petr (referee) ; Mikulka, Jan (advisor)
This thesis deals with a measurement and interpretation of NIR spectra of bacterial cells and design of biosensor using this analytical technique. In the first chapter, there is introduction of current state of knowledge in the field of NIR spectroscopy in microbiology and technology of fiber optic biosensors. The summary of this chapter shows that NIR is a suitable technique for direct molecular analysis of bacteria, but it suffers from low sensitivity and insufficient interpretation of bacterial spectra. In the next part of the thesis, there is a theoretical background of spectral analysis techniques and technology of fiber optic sensors. In the practical part of this work, there is suggested the elimination of disadvantages of NIR spectroscopy in microbiology by a series of experiments used for interpretation of NIR spectra of bacteria and design of fiber optic sensor to increase sensitivity of this technique. In this work, spectral regions important for the identification of bacterial strains were determined and partially interpreted and the sensor for bacterial analysis capable of classifying strains based on 105 captured cells was designed. Therefore, the objectives of this work were fulfilled.
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Laser source with fiber-optic output
Roupec, Tomáš ; Mikulka, Jan (referee) ; Drexler, Petr (advisor)
This term project deals with the semiconductor laser components, and how it works. Additionally, there is an optical fiber ant networking with laser. It is written of power and cooling laser diodes and such information suggested the possible involvement of the laser diode. At the end of this work is designed laser´s exciter with charging and adjacent circuits.
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