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QT interval measurement in electrograms
Ondráček, Vladimír ; Vítek, Martin (referee) ; Kolářová, Jana (advisor)
This diploma thesis focuses on determination of the QT interval in ECG. The thoretical part desribes physiology of the heart, electronic activity of the heart and possible methods of ECG measurement. The theoretical part also describes methods of signal processing, the processed signal is then used for determination of the QT interval. The practical part focuses on two chosen methods of QT interval determination and on implementation of the methods in a computer program. The results part is evaluation of measured QT intervals and a comparision of the results with reference values.
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Processing of electrocardiograms
Princ, Martin ; Vítek, Martin (referee) ; Kolářová, Jana (advisor)
This work concerns with problems of the QT sequences detection in ECG signal. The first part introduces electrophysiology of heart and his electrical manifestation. For main detection were used two algorithms, which were afterwards modified and programmed in Matlab. The work includes developed custom applications for measurement and evaluation of the length of QT interval. The final lengths of the QT interval, which we got from this two methods, were compared with reference length.
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Measurement and analysis of phonocardiographic signal
Všetula, Petr ; Kolářová, Jana (referee) ; Kolář, Radim (advisor)
This work is engaged in measurning and analysis of phonocardiographic signal. Effect of characteristics and parameters of used parts is examined due to quality of measurement of these signals. The emphasis is put especially on the amplifiers and microphones. The measurment is done by measure card PCI6221E. Data processing and analysis is proceeding by the help programmes, which are created in programmatic environmen LabView.
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Recognition methods for biosignals
Juračka, Zdeněk ; Vítek, Martin (referee) ; Kolářová, Jana (advisor)
The thesis is focused on the recognition methods study used in one-dimensional signal processing. A lot of recognition methods exist, this thesis briefly describes the principle of some of them, e.g. artificial neural networks, fuzzy systems, expert systems and decision trees. Dynamic time warping (DTW) method has been chosen for signal processing available from UBMI database. DTW can be used as a non-linear signal processing method. The result of this method is to determine the similarity of two compared signals on the basis of their distance calculation. One of the reasons for choosing this method was the possibility of various length signal processing. The principle of the method as well as the calculation of the distance between two input data sequences is described in the thesis. DTW path finding method is also mentioned. The method was applied on randomly selected numbers and a set of simulated signals. The method was applied to ECG and action potential signals recorded on the isolated rabbit heart. DTW was used to evaluate shape changes of these signals in repeated phases of the experiment known as ischemia and reperfusion. Selected cardiac cycles were detected and included into different experiment phases on the basis of calculated distance results using DTW. Sensitivity was selected as an evaluative criterion of this classification method. It reached a value of 65%. DTW algorithm was further tested on the selected cardiac cycle mapping to the corresponding minute record in the selected experiment phase. It reached a sensitivity of 68.3%. The motion artifact appearance was monitored using DTW on AP signals. The method functioned more precisely on signals measured in ischemia phases. Along with the above mentioned, the thesis discusses all aspects of heart electrical manifestation activities called as ECG signals and action potentials, such as origin, propagation, recording, post-processing and measuring out.
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Analysis of Heart Rate Variability
Škrtel, Karol ; Kolářová, Jana (referee) ; Provazník, Ivo (advisor)
The project describes the methods useful for observe changes of heart rate in ECG signal. Heart rate variability become (HRV) the conventionally accepted term to describe variations of NN intervals between consecutive heart beats and generally it is function of instantaneous heart rate or NN interval on time. HRV may be evaluated by time domain or frequency domain measures. In Matlab was developed algorithm, realized like function, which counts HRV parameters from ECG signal series. Analysis in time domain adverts to high correlation between statistic and geometric parameters and similarly with signal HRV. Results of frequency domain analysis shows similarity of power spectral density, which was calculated by two different ways (from interpolated and no interpolated signal HRV). Functionality of developed algorithm was verified on each signal. Project results have signification in progress of analysis ECG signal methods with a view to observe pathological changes in heart rate.
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Recognition of isolated words
Ondruška, Jiří ; Švrček, Martin (referee) ; Kolářová, Jana (advisor)
Human speech recognition in biometric systems is an actual problem, which science intensively deals with. One of most used methods is the method of hidden Markovov’s models. Attention in isolated words recognition is focused on characteristic speech signal parameters obtaining, enabling most clear identification due to hiddem Markov model application. This work concentrates on biometric systems, its methods, and then is focused on isolated words recognition problems. The hidden Markov model recognition system with usage of some Matlab functions is designed. Concept focuses on characteristic speech signal parameters obtaining, code book making through vector quantization, words model training and finally probability of concrete model and obtained word similarity evaluation. Ratio for one speaker's spoken words recognition reaches 40%.
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Measurement of cardiovascular parameters
Szpyrc, Bogdan ; Rychtárik, Milan (referee) ; Kolářová, Jana (advisor)
This bachelor thesis deals with the questions of anatomy and physiology of the heart. The diagnostic system BIOPAC is used in order to measure the electrical activity of the heart by a 12-lead electrocardiogram (ECG) and to evaluate the heart rate. The ECG signal is transformed into a vectorcardiogram (VCG) from which the direction of the electrical axis of the heart is deducted. Own experiment will be suggested in order to detect a load reaction and cessation of breath on the heart rate and a load reaction on an inclination of the electrical axis of the heart. A programme application will be designed so as to simplify the analysis of values. The application will allow reconstruction of the ECG signal into a VCG scheme and an automatic calculation of the heart rate and the inclination of the electrical axis of the heart. By means of a statistical analysis the results of measurements will be evaluated.
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Electromyography, measurement of muscle electric activity
Kořínek, Peter ; Provazník, Ivo (referee) ; Kolářová, Jana (advisor)
The task of this thesis was to become acquainted with the issue of measuring of muscle electric activity.In the theoretical part we became familiar with the computer measuringsystem BIOPAC and its options to measure monitored magnitudes. This continue with practical part, in which we watch the problematic according to a theory in a group of people. We learned data with BIOPAC according to protocol of the result of physicaleffort influence on EMG. In the end the results were statistically analysed. The data as a product offallowing research were verified by hypothesis. In thelast step, the data are presented in graphical user interface development environment. After loading of the EMG of measured person, the process are displayed-without, with and after the power with onus. It is possible to choose from different analyses.
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Evaluation of patient dose in mammography
Polášková, Markéta ; Sekora, Jiří (referee) ; Kolářová, Jana (advisor)
Breast cancer presents serious epidemiological problem, in result of which die more than 2 000 czech women every year. Screening mammography is one of the most expanded and most effective examinations for early detection of this desease but one has to take into account an inconsiderable risk connected with the procedure based on X-ray ionizing radiation. This diploma thesis deals with evaluation of the dose absorbed by the tissue. It contains the description of evaluation of the average dose in glandular tissue on PMMA phantom, as well as results of the measurements on conventional and digital mammograph. A data file with exposure parameters from mammography screening is included and interpreted. Also the Monte Carlo method was used for the dose evaluation, the thesis contains the brief description of the method, concept of analysis model in mammography and results of simulations.
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