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Time-frequency analysis of electrograms
Doležal, Petr ; Ronzhina, Marina (referee) ; Kolářová, Jana (advisor)
This thesis deals with time-frequency analysis of electrograms measured on isolated guinea pig hearts perfused according to Langendorff. Time-frequency analysis is based on algorithms Matching Pursuit and Wigner-Ville Distribution. The theoretical part describes the basics of electrocardiography, measurement on isolated hearts, the theory of approximation method Matching Pursuit and its combination with the Wigner-Ville distribution spectrum showing the energy density of the signal. Also other common approaches of time-frequency analysis are presented including the theory of continuous wavelet transform. The presented algorithms were tested on a set of electrograms, on which were induced ischemia within measurement followed by reperfusion. The proposed method allows for the fast detection of ischemia without any a priori knowledge of the signal, and also serves as a tool for measurement of EG important points and intervals. In the conclusion efficacy of the method was presented and its possible uses has been discussed.
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Establishing Mutual Links among Brain Structures
Klimeš, Petr ; Hlinka,, Jaroslav (referee) ; Krajča,, Vladimír (referee) ; Halámek, Josef (advisor)
The Human brain consists of mutually connected neuronal populations that build anatomically and functionally separated structures. To understand human brain activity and connectivity, it is crucial to describe how these structures are connected and how information is spread. Commonly used methods often work with data from scalp EEG, with a limited number of contacts, and are incapable of observing dynamic changes during cognitive processes or different behavioural states. In addition, connectivity studies almost never analyse pathological parts of the brain, which can have a crucial impact on pathology research and treatment. The aim of this work is connectivity analysis and its evolution in time during cognitive tasks using data from intracranial EEG. Physiological processes in cognitive stimulation and the local connectivity of pathology in the epileptic brain during wake and sleep were analysed. The results provide new insight into human brain physiology research. This was achieved by an innovative approach which combines connectivity methods with EEG spectral power calculation. The second part of this work focuses on seizure onset zone (SOZ) connectivity in the epileptic brain. The results describe the functional isolation of the SOZ from the surrounding tissue, which may contribute to clinical research and epilepsy treatment.
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Time-frequency analysis
Tráge, David ; Hadinec, Michal (referee) ; Kubásek, Radek (advisor)
The aim of this bachelor`s thesis is to explore possibilities of solving time-, frequency analysis a their combination time-frequency analysis by different methods for example Fourier transform a Wavelet transform. Going through this project we will get know each transformation and we will make clear procedure of their solving and first of all their advantages and disadvantages in view of accuracy of frequention`s mark in time.
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Classification of microsleep by means of analysis EEG signal
Ronzhina, Marina ; Smital, Lukáš (referee) ; Čmiel, Vratislav (advisor)
This master thesis deals with detection of microsleep on the basis of the changes in power spectrum of EEG signal. The results of time-frequency analysis are input values for the classifikation. Proposed classification method uses fuzzy logic. Four classifiers were designed, which are based on a fuzzy inference systems, that are differ in rule base. The results of fuzzy clustering are used for the design of rule premises membership functions. The two classifiers microsleep detection use only alpha band of the EEG signal’s spectrogram then allows the detection of the relaxation state of a person. Unlike to first and second classifiers, the third classifier is supplemented with rules for the delta band, which makes it possible to distinguish the 3 states: vigilance, relaxation and somnolence. The fourth classifier inference system includes the rules for the whole spectrum band. The method was implemented by computer. The program with a graphical user interface was created.
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Analysis of stabilometric signals in frequency domain
Netopil, Ondřej ; Hejč, Jakub (referee) ; Kozumplík, Jiří (advisor)
This work deals with the metods frequency and time frequency analysis of stabilometric signal. In the introroduction is described theory about posturography and posturographic measurment. The work contains describtion of stabilometric parametrs in time domain (1D and 2D parametrs) and in frequency domain. The aim is create review of basic metods used to processing and preprocessing of stabilometric signals and comparing this methods . In work is realized ferquency analysis used Frourier transfrmation and Burg method and time-frequency analysis used Short time Frourier transformation and Wavelet transformation. One part of program is aimed on comparison of this methods.
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Removal of a Known Signal from a Recording
Hošek, Pavel ; Žmolíková, Kateřina (referee) ; Černocký, Jan (advisor)
The goal of this bachelor thesis is to design and implement method for removing known signal from recorded sound. The introductory part of the thesis summarizes the theory of sound properties, basics of signal processing, and system identification. Subsequently, the data are presented and the way of testing is stated. Afterwards, the development of a method for removing a known signal from a recording is described. Finally, experiments are performed, which include a comparison of selected methods. The best methods achieved relatively good results and they were mostly able to remove the known signal sufficiently.
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Time-frequency analysis of Czech republic gross domestic product
Tráge, David ; Poměnková, Jitka (referee) ; Maršálek, Roman (advisor)
The aim of this master's thesis is to get familier with problematic and concepts of econometrics (GDP, investment, usage and others). We see into used data mainly their characters and expectations and we discuss possibilities of frequention and time-frequention analysis of these data by Fourier and Wavelet transform. Data of quarter development of gross domestic product in Czech Republic, EU and USA will be analysed by the help of programm MATLAB. Data will be filtered by three ekonomic filters: Hodrick-Prescott, Baxter-King and Christiano-Fitzgerald filters. The aim is to find cyclic elements in developments of GDPs and to suggest an optimal type of analysis.
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Non-contact detection of physiological parameters from image sequences
Bršlicová, Tereza ; Janoušek, Oto (referee) ; Kolář, Radim (advisor)
This thesis deals with the study of contactless and non-invasive methods for estimating heart and respiratory rate. Non-contact measurement involves sensing persons by using camera and the values of the physiological parameters are then assessed from the sets of image sequences by using suitable approaches. The theoretical part is devoted to description of the various methods and their implementation. The practical part describes the design and realization of the experiment for contactless detection of heart and respiratory rate. The experiment was carried out on 10 volunteers with a known heart and respiratory rate, which was covered by using of a sophisticated system BIOPAC. Processing and analysis of the measured data was conducted in software environment Matlab. Finally, results from contactless detection were compared with the reference from measurement system BIOPAC. Experiment results are statistically evaluated and discussed.
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Removal of a Known Signal from a Recording
Hošek, Pavel ; Žmolíková, Kateřina (referee) ; Černocký, Jan (advisor)
The goal of this bachelor thesis is to design and implement method for removing known signal from recorded sound. The introductory part of the thesis summarizes the theory of sound properties, basics of signal processing, and system identification. Subsequently, the data are presented and the way of testing is stated. Afterwards, the development of a method for removing a known signal from a recording is described. Finally, experiments are performed, which include a comparison of selected methods. The best methods achieved relatively good results and they were mostly able to remove the known signal sufficiently.
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