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Transmission Diagnostic Tool
Škvarka, Jakub ; Řehák, Kamil (referee) ; Prokop, Aleš (advisor)
This master's thesis focuses on the development of a tool for diagnosing transmission systems in programming language Python. The aim of this work is to create a flexible software solution that enables data acquisition and analysis primarily from gearboxes using the LAN-XI analyser, which is adaptable to the individual needs of the user and allows for process automation. The developed tool fully replaces conventional software, providing opportunities for automation and customization of the data acquisition process. The thesis also presents a specific example of the tool's application on real data from a technical experiment, demonstrating its functionality and practical use.
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Fourier transformation for exon prediction
Rusina, Michal ; Škutková, Helena (referee) ; Maděránková, Denisa (advisor)
In this bachelor thesis there are described the methods of the prediction of exon. The first part is aimed at the difference between the prokaryotic and eukaryotic organisms, the description of the DNA structure and the explanation of the terms exon and intron. The second section of the theoretic part includes four methods of the prediction of exons namely dynamic programming, neural networks, hidden Markov models and discrete Fourier transform. In the practical part there was created the program called Predikce_exonu that searches exons in nucleotide sequences and works on the principle of the Fourier transform. This algorithm together with 3 freely available programs was tested on 25 sequences and the success of their prediction was described by sensitivity and specificity.
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Monitoring of hydraulic machines using acoustic emissions
Závorka, Dalibor ; Pochylý, František (referee) ; Habán, Vladimír (advisor)
The goal of this diploma thesis is to clarify possibilities of usage of acoustic emission as a hydraulic machinery diagnostics tool. Especially for exposing presence of ruptures or cracks in the parts of machine, assuming changes in acoustic exposure of the part during operation. This clarification is based on series of simple measured experiments, which consist of monitoring the bolt placed in fluid stream inside of a pipe. This bolt was preloaded against inner wall of pipe by appropriate tightening torque. This preload is supposed to simulate effects of the size of rupture. High preload simulates small rupture or none in object and respectively small preload is supposed to simulate big rupture. A group of pressure sensors and accelerometers measures experiments and their evaluations are processed by script created in software MATLAB. Outputs of this script are charts with effective values of respective sensors from the entire record split into individual frequency spectrums. These charts compare spectrums of each configuration to judge effects of parameters changes.
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Diagnosis of electromagnetic origin vibrations in asynchronous motor
Koníček, Pavel ; Dostál, Lukáš (referee) ; Janda, Marcel (advisor)
The aim of this master´s thesis is to introduce methods of diagnostics of vibrations in electrical machines. Describe the various vibration sources located inside and outside of the electric machine. Description of the sources of vibration is then preferably dedicated to vibration of electromagnetic origin. There is a description of the construction of an asynchronous motor and the magnetic circuit, the theory of vibrations and their origin. Described are also vibration sensor enables measurement and mathematical tools for their evaluation. In this work also practical vibration measurements on an asynchronous motor, data processing, their subsequent analysis and computer simulation of electromagnetic vibration origin. The conclusion of this work is devoted to the evaluation of the data obtained.
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Thresholding rules for noise reduction in sound signals
Ráček, Tomáš ; Schimmel, Jiří (referee) ; Balík, Miroslav (advisor)
The master's thesis focuses on the study of algorithms dealing with noise separation from musical signal. The first chapter is an introduction into methods which are used for noise removal of the musical signal. Furthermore, this chapter describes theory to the issue, specifically a description of transformations for converting from time to frequency domain, and finally thresholding method of spectral coefficients is explained in detail. The aim of the second chapter is an analysis of the proposed algorithm, which is engaged in testing. From the beginning fast algorithms of gradual transformation are described and then a detailed description of the algorithm as a whole. Later, this chapter deals with the selection of audio recordings and with preparation of these recordings for the actual testing. Finally, testing of audio samples is presented in the third chapter of this thesis. This chapter also concludes comparison of individual transformations, achieved results and review of algorithm.
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Detection of the retinal nerve fibre layer
Kunc, Martin ; Szabó, Zoltán (referee) ; Kolář, Radim (advisor)
This thesis is deals with the nerve fibre layer in the colour ophthalmology images of retina. The thesis describes how can we use finding of nerve fibre layer and how was it solved in the past. In the thesis are proposed the methods that are based on processing and scoring frequency spectrums of individual sample of retina. At first here are described the methods of detection on the artificial generated samples that just simulate the nerve fibre layer. Then the thesis concentrates on processing of real images of retina. Because of the bloodstream, that depreciates processing at real images, are all surveyed samples are chosen manually. Except detection the nerve fibre layer itself, the thesis also deals with determination of direction their dissemination.
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Cavitation assessment from flow rate drop and high-frequency pressure pulsations.
Šebek, Miloš ; Hudec, Martin (referee) ; Habán, Vladimír (advisor)
Main issue of this master´s thesis deals with high-frequency pulsations caused by cavitating hydraulic components (in this case nozzle and throttle valve). In first measurement on the nozzle was not a high-frequency sensor set in the way, so the evaluation was incorrect. After re-setting of the way was the nozzle measured again and the pulsations were evaluated correct this time. During the last measurement was the sensor located behind the throttle valve, which was with gradual opening and cavitation treatment measured. Resulting dependencies worked out on time dependence. A special mathematical method, Fourier transformation, was used. It transformed pressure amplitudes into frequency dependence. Evaluation of dependecies is the basic step for frequency band assesment, in which the cavitation on particular components happens.
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Venturi nozzle shape influence on hydrodynamic cavitation
Mračko, Patrik ; Balko, Marek (referee) ; Rudolf, Pavel (advisor)
Thesis focuses on the influence of various differently shaped diffusers of Venturi nozzle on the cavitation, which occurs during flow of liquid through said nozzle. Several models with different shapes of diffuser's wall were designed. Cavitation in these models was then investigated with numerical calculation. Two physical nozzles were made according to designed models and tested on experimental circuit. As part of the experiment, the cavitation inside the nozzles was measured with flow of liquid corresponding to a large range of cavitation numbers. Results of this experiment were used to determine which model of the nozzle is more effective in creation of a cavitating flow.
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Study of electrical and dielectric properties of thin polymer films
Miklíková, Zdeňka ; Novák, Vítězslav (referee) ; Zmeškal, Oldřich (advisor)
The thesis is focused on the study of electric and dielectric properties of thin-film organic materials that can be used as an active layer of photovoltaic cells. Primarily were studied the properties of the layers on the glass substrate, which consist of a thin active layer of mixture ZnPc/PCBM with Al or Au contact. On the selected samples were first measured current-voltage characteristics in the dark and during the exposure then on the selected samples were measured frequency dependences (impedance spectra) in the dark and finally on the selected samples were measured relaxation characteristics (transient response analysis – current dependences on time at constant voltage) in the dark. The measured data for transient measurement were evaluated using the methods of fractal analysis in HarFA. The results will be used to optimize the properties of photovoltaic cells.
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