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Detection of QRS complexes in ECG signals
Zhorný, Lukáš ; Ronzhina, Marina (referee) ; Kozumplík, Jiří (advisor)
This thesis deals with the detection of QRS complexes from electrocardiograms using time-frequency analysis. Detection procedures are based on wavelet and Stockwell transform. The theoretical part describes the basics of electrocardiography, then introduces common approaches to time-frequency analysis, such as short-time Fourier transform (STFT), wavelet transform and Stockwell transform. These algorithms were tested on a set of electrograms from the MIT-BIH and CSE-MO1 arrhythmia database. For the CSE database worked best the method based on the wavelet transform with the filter bank Symlet4, with the resulting value of sensitivity 100 % and positive predictivity 99.86%. For the MIT database had the best performance the detector using the Stockwell transform with values of sensitivity 99.54% and positive predictivity 99.68%. The results were compared with the values of other authors mentioned in the text.
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Spectrophotometry of ROS species with focus on hydrogen peroxide
Zhorný, Lukáš ; Hořavová, Lenka (referee) ; Provazník, Ivo (advisor)
The main theme of this work is spectrophotometry. The first chapter describes the theoretical problems of the topic, relevant units and formulas for calculating the absorbance of the solutions of given concentrations. Further disclosed herein is a spectrophotometer, its individual parts, and the principle on which the unit is based. The last chapter of the theoretical introduction to this work is focused on the production of ROS in living organisms and especially in plants, and then there are some spectrophotometric methods for determining the concentration of ROS. The practical part describes the method using TiCl4 and method using KI. Both methods were used to determine the hydrogen peroxide concentration and subsequent measurement of absorbance of solutions of standard hydrogen peroxide added interfering substances. Then, the statistical analysis of the measured data and the assessment of the impact of these interferents to measure absorbance. The first of these methods proved to be suitable for a given measurement.
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Detection of QRS complexes in ECG signals
Zhorný, Lukáš ; Ronzhina, Marina (referee) ; Kozumplík, Jiří (advisor)
This thesis deals with the detection of QRS complexes from electrocardiograms using time-frequency analysis. Detection procedures are based on wavelet and Stockwell transform. The theoretical part describes the basics of electrocardiography, then introduces common approaches to time-frequency analysis, such as short-time Fourier transform (STFT), wavelet transform and Stockwell transform. These algorithms were tested on a set of electrograms from the MIT-BIH and CSE-MO1 arrhythmia database. For the CSE database worked best the method based on the wavelet transform with the filter bank Symlet4, with the resulting value of sensitivity 100 % and positive predictivity 99.86%. For the MIT database had the best performance the detector using the Stockwell transform with values of sensitivity 99.54% and positive predictivity 99.68%. The results were compared with the values of other authors mentioned in the text.
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|
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Spectrophotometry of ROS species with focus on hydrogen peroxide
Zhorný, Lukáš ; Hořavová, Lenka (referee) ; Provazník, Ivo (advisor)
The main theme of this work is spectrophotometry. The first chapter describes the theoretical problems of the topic, relevant units and formulas for calculating the absorbance of the solutions of given concentrations. Further disclosed herein is a spectrophotometer, its individual parts, and the principle on which the unit is based. The last chapter of the theoretical introduction to this work is focused on the production of ROS in living organisms and especially in plants, and then there are some spectrophotometric methods for determining the concentration of ROS. The practical part describes the method using TiCl4 and method using KI. Both methods were used to determine the hydrogen peroxide concentration and subsequent measurement of absorbance of solutions of standard hydrogen peroxide added interfering substances. Then, the statistical analysis of the measured data and the assessment of the impact of these interferents to measure absorbance. The first of these methods proved to be suitable for a given measurement.
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