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Optimization of Basic Magnetic Field Homogeneity in MR Tomography
Hadinec, Michal ; Brančík, Lubomír (referee) ; Frollo, Ivan (referee) ; Bartušek, Karel (advisor)
This thesis is concerned with problems of measuring and mapping of magnetic field in MR tomograph, for purpose of magnetic flux density homogeneity optimization. Attention is paid to mapping techniques on rotary symmetric volume and to ways of magnetic fields optimization with utilization of passive and active correction systems. Theoretical analysis of magnetic field decomposition with utilization of spherical harmonics and numerical decomposition is made. Mapping and approximation techniques of basic magnetic field are verified by experiments in the laboratory at the Institute of Scientific Instruments AS CR in Brno.
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Image composition
Smital, Petr ; Petyovský, Petr (referee) ; Richter, Miloslav (advisor)
This thesis deals with methods of improving the quality of image output of an electron microscope by composing consecutive frames. The thesis contains a brief description of an electron microscope and the problems that deteriorate its image quality, and three basic mathematical algorithms that can be used to remove them. These are the simple averaging method, the method of least squares and the method of vector space. For all of the methods, the thesis describes ways of their implementation, the possibilities of their use and their mutual comparison. This thesis also deals with the problem of so-called superresolution, i.e. exceeding the physical resolution of a sensor using the methods mentioned above, and the problem of electron beam centring.
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Least-Squares Method in System Identification
Matějka, Jiří ; Bělohradský, Petr (referee) ; Máša, Vítězslav (advisor)
This bachelor thesis deals with the description of the least squares method and its application in system identification of dynamic processes. It contains mathematical derivation of least squares method and basic principles of system identification. It describes parametrization of an mathematical model of experimental unit for biomass combustion.
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Identification of DC motor parameters
Kabelka, Ondřej ; Veselý, Libor (referee) ; Pohl, Lukáš (advisor)
This bachelor´s thesis deals with identification of parameters of the DC motor. An identification program in LabVIEW with data processing in Matlab has been created. After the identification of electrical and mechanical parameters of the motor there are current regulators and velocity regulators designed and implemented in the LabVIEW enviroment as a verification of the correctness of the identification.
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Hydraulic roughness of water supply pipes
Náplavová, Eva ; Hofmannová, Lenka (referee) ; Ručka, Jan (advisor)
This bachelor’s thesis deals with hydraulic roughness of water pipelines, its consideration while making a hydraulic model and subsequent calibration of hydraulic simulation model. In the theoretical part literary review about current approach to hydraulic modeling of water mains and its possible future direction is carried out, as well as an overview of used roughness coefficients, computational formulas and possible approaches to calibration of the hydraulic model. In the practical part of the thesis, a matematical model of the supply main of the water mains network of Hvozdná is compiled and is followed by its calibration. The method of weighted least squares is used as an objective function. Optimization methods are used to minimize the value of the objective function and thus to determine the hydraulic roughness of supply main.
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Kinetics of Inkjet Dyes Degradation
Buteková, Silvia ; Mikula, Milan (referee) ; Klusoň, Petr (referee) ; Veselý, Michal (advisor)
The stability of inkjet print is influenced by a lot of factors. Mutual effects of these factors accelerate the print degradation. The surrounding environment in image stability plays an important role, when the prints degrade especially by the light. The degradation of inkjet prints is presented as a decrease of dye or multiple dyes. It is necessary to know the dye concentration for the dye decrease prediction in the time. This dissertation thesis deals with the study of kinetics and changes in electron and molecular structure of digital photography prints after accelerated ageing tests. The study of resistance of inkjet prints was realized on one type of media using three different sets of inks. Changes in printed colours were measured and evaluated in calibration (by PLS calibration and least squares method). On the basis of calibration the dye decrease prediction of real samples in receiving layer was evaluated. Changes in electron and molecular structure were analysed on KBr pellets by FTIR an UV-Vis spectroscopy.
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Calibration of hydraulic model of water supply network
Náplavová, Eva ; Tureček,, Jan (referee) ; Ručka, Jan (advisor)
This diploma thesis deals with calibration of hydraulic simulation models, especially with methods used for calibration and parameters that are modified during calibration. The literature review in the field of mathematical modeling, basic principles applied in hydraulic modeling and the current approach to calibration and data collection is done in theoretical part. In the practical part of the thesis, a hydraulic model of the group water supply system Horní Dunajovice is built and subsequently calibrated. The calibration is first performed manually for the normal operational status and then using a calibration software created for this purpose for a load case with high velocity.
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Adaptive controllers with principles of artificial intelligence
Pitra, Michal ; Malounek, Petr (referee) ; Pivoňka, Petr (advisor)
The diploma thesis is focused on an adaptive control, especially in a self-tuning controller area. The thesis is divided into two main parts. The first part deals with identification methods of the adaptive control. The recursive least squares algorithm and the neural network method are the most popular identification methods. These methods are contrasted and the identification quality evaluation is done. The second part compares various types of the adaptive controllers with a non-adjustable PSD controller. The adaptive controllers are investigated from the various identification method point of view. The user graphic interface was realized for the identification and regulatory part. The time behavior of system responses after incoming disturbance and dynamic process changes during simulation systems control is compared with a physical model connected to B&R PLC. The comparison is done with the application of Matlab/Simulink program.
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