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Preprocessing of ECG signals for detection of significant points
Strouhal, Martin ; Smital, Lukáš (referee) ; Vítek, Martin (advisor)
This work aims to find out the best filter design method for getting out parasitic elements in ECG signal. There are defined origin and frequency qualities of these elements. Individua filter design methods are compared according to number of filter coefficients, effectivity and influenc to useful signal. I created several digital filters by various design methods and tested them on ten ECG signals. From the experiment ensued: all filters were able to get out brum, but filters designed by distribution of zeros and poles had the lowest number of coefficients. On the other hand same filters were disable to get out drift with very sheer course.
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Statistical Analysis of Wiener Process Based on Partial Observations
Hrochová, Magdalena ; Hlubinka, Daniel (advisor) ; Omelka, Marek (referee)
Wiener process-a random process with continuous time-plays an important role in mathematics, physics or economy. It is often good to know whether it contains any deterministic part, e.g. drift or scale. However, it is nearly impossible either observe the whole trajectory of the process or preserve its full history. This thesis deals with a statistical analysis based on partial observations, namely passage times through some given barriers. We propose several statistical methods for testing hypotheses about drift or scale using these observations. As supporting methods, we consider the maximum likelihood theory, non-parametric test against a trend, and binomial test. For testing the value of scale in the model with no drift and constant scale we recommend maximum likelihood theory. We derive the estimate and related tests in the case of observing only three barriers. The simulation study suggested observing more barriers for testing monotony of scale in a model with linear drift, or testing monotone and convex/concave drift in a model with constant scale. 1
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Electromigration of defects in (CdZn)Te single crystals.
Pekárek, Jakub ; Belas, Eduard (advisor) ; Grill, Roman (referee)
In the present work we study effect of electromigration of defects in CdTe material in external electric field at various temperatures and biases. The aim was to verify this effect using a set of electric contacts arranged linearly along the sample. These contacts as a potential probes was used for the detection of the drift of the local resistance modulation. We try to determine under what conditions and why it happens and then decide how this effect can be used for purification of semi-conducting samples and for preparation of semi-insulating material.
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Precise voltage references
Budáč, Peter ; Ing. Miroslav Horáček, Ph.D., ÚPT AVČR Brno (referee) ; Zobač,, Martin (advisor)
The aim of this thesis is the realization of the workplace to measure long-term stability and temperature coefficient of precision voltage references. It analyses individual solutions precision voltage references and their important parameters for the stability of the reference voltage. It deals with the influence of thermoelectric voltages and methods how to minizme their effect on measurement error . In conclusion it proposes a solution of this measuring workplace, and evaluate the results measuring of long-term stability and temperature coefficient on selected precision voltage references.
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Narrow Band Filtering of ECG Signals
Němeček, Tomáš ; Walek, Petr (referee) ; Kozumplík, Jiří (advisor)
Main objective of this bachelors thesis, was to learn about issues and possibilities of ECG filtration. This thesis is focused on narrowband filtration by Lynn’s filters. The objective for this thesis was to design filters for filtration of interferences called drift and brum. Both of them should not affect the relevant part of signal.
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Simulation of charged particles motion in electrical and magnetic fields
Zavřel, Marek ; Kloc, Petr (referee) ; Aubrecht, Vladimír (advisor)
In the first part of this bachelor thesis has been explained a basic idea of plasma state. In the second part have been described charged particle motions in various configurations of electric and magnetic fields. These motions are: accelerating and deflection of charged particle by electric field, gyration in magnetic field and drift motion in crossed electric and magnetic fields. Principles of magnetic mirror and magnetic trap were described as well. In the third part have been described operating principles and manipulation with simulation program, which is the main outcome of this thesis. Simulation program draws trajectories of mentioned charged particle motions in homogenous electric and magnetic fields.
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An Extended Model of a MEMS Gyroscope: Design and Identification
Vágner, Martin ; Sopata,, Milan (referee) ; Tůma, Jiří (referee) ; Beneš, Petr (advisor)
The thesis is aimed on measurement and modeling of MEMS gyroscopes based on input-output characteristics. The first part briefs the state of the art. The second part is dedicated to measurement methodology. Critical points and sources of uncertainty are discussed and evaluated using measurements or simulations. The last part shows key characteristics of MEMS gyroscopes based on the survey of a group of different sensor types. The results have revealed significant influence of supply voltage that causes bias drift of the gyroscope and bias drift of the internal temperature sensor. The error can be comparable to temperature drift; however, this effect is not addressed in the literature. The second observed effect is temperature dependency of angle random walk. In the last part, a general model of a MEMS gyroscope is rewritten to reflect observed effects. Moreover, the structure is selected to be easily extendable and the coefficients are expressed to allow a comparison of nominal parameters of different sensors.
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ECG noise generator
Mikuláš, Karol ; Kozumplík, Jiří (referee) ; Hrubeš, Jan (advisor)
Real ECG signal contains undesirable artifacts arising from its capture. Due to loss of diagnostically useful information in the noise signal and followed by the filtering the signal is important to know the characteristics, the most common symptoms and causes, to avoid or minimize the noise ECG signal. ECG noise generator is an educational program designed to serve the learning methods of filtering the noise signal. The user program can verify the effectiveness of the chosen method and the extent of deformation of the useful signal. The program includes basic types of artifacts, such as powerline interference, baseline wander, drift, impulse noise, myopotentials and change of baseline wander of ECG signal, which can be prepared noise signal from a database or other signal selected by the user.
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Time Varying Filters for ECG Signals
Peterek, Jan ; Vítek, Martin (referee) ; Kozumplík, Jiří (advisor)
The aim of this master’s thesis is to create a multiband stop derived from Lynn filters for suppressing mains hum and baseline variation (drift). The first part of the thesis is focused on brief theoretical introduction to the distortion types affecting ECG signal and twelve lead connection. The following practical part describes free realizations of ECG filter and ECG signal filtration. The filter has been tested both on distorted and on non-distorted signal. Finally filters’ error rate was computed from CSE database signals.
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Computer modeling of MOSFET transistor
Major, Jan ; Harwot, Ondřej (referee) ; Pokorný, Michal (advisor)
Work is focused on computer modeling of PN junction and MOSFET transistor in the program COMSOL Multiphysics and in program TiberCAD. The text is discussed on the drift and diffusion in semiconductors. Also shown is a method of modeling the PN junction and MOSFET transistor in the programs and compare models.
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