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Design and implementation of the plasma control system for the COMPASS tokamak
Janky, Filip ; Horáček, Jan (advisor) ; Kudrna, Pavel (referee) ; Svoboda, Vojtěch (referee)
Design and implementation of the plasma control system Mgr. Filip Janky The COMPASS tokamak was recommissioned in 2007 and it needed new digital controllers for its experimental research. This thesis presents the design and imple- mentation of control of main plasma parameters such as plasma current, plasma position, plasma shape and electron density. Improved plasma current control with resetting set points suppresses overshooting and thus increases the length of the flat top phase. A method for estimating the plasma position, gain tuning for the controller and decreasing latencies and delays to obtain robust position control are presented. Lower delays improve plasma stability and decrease the frequency of disruptions. The plasma shape controller is a feedforward controller with a method to suppress oscillations which are coming from mutual inductance between power supplies controlling plasma horizontal position, plasma shape and plasma current, which all use the same coil. Averaged electron density is corrected in real-time according to the interferometer line of sight and a non-linearity of measurement. Controllers and their improvements described here, played a major role in achiev- ing H-mode scenario and fulfilling the experimental program. Keywords: tokamak, plasma current control, plasma position...
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Arithmetic coding on GPU
Buneev, Leonid ; Horáček, Jan (advisor) ; Kruliš, Martin (referee)
The aim of this thesis is to investigate possibilities for creating parallel arithmetic coding implementation and measure performance improvements. In the first part, short overview of Arithmetic coding with its serial implementation (FastAC by Amir Said) is presented. The thesis then describes principles of work with GPUs and identifies possibilities of algorithm improvement and parallelization. Several parallel implementations are given, with varying performance improvements and occasional drawbacks. In conclusion, thesis provides results of performance tests of our implementation, as well as discussion about feasibility of applying GPU-oriented version of algorithm instead of serial one in real-world applications. Powered by TCPDF (www.tcpdf.org)
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Codes, rings and modules
Horáček, Jan ; Žemlička, Jan (advisor) ; Šťovíček, Jan (referee)
This work is focused on linear error-correcting codes over chain rings. By a linear code over a chain ring R of length n, we mean a R-submodule of the module Rn . The basic introduction to the theory of finite commutative chain rings and linear codes over them is given. We especially emphasize here their al- gebraic description. Minimal homogenous and Hamming distances of these codes are extensively studied. We explain, how the generalized Gray map can transform linear codes over a chain ring into general non-linear codes over a field. We deal with the construction of linear codes over a chain ring and the construction of generator matrices based on random generation is described. Obtained codes are compared with known results.
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Experimental and theoretical study of utilization of probe methods for plasma diagnostics
Peterka, Matěj ; Tichý, Milan (advisor) ; Horáček, Jan (referee)
The ball-pen probe is a unique probe recently developed at the Institite of Plasma Physics in Prague. It has been designed for direct measurement of plasma potential at the CASTOR tokamak. Nowadays, it is used routinely at several tokamaks in Europe, and the first tests in low-temperature plasma have also already been performed. The aims of the thesis are primarily experimental. A ball-pen probe has been constructed from available materials, which is suitable for systematic measurements of radial profiles in the low-temperature plasma of a cylindrical magnetron. By means of comparison to other diagnostics, it was proved that ball- pen probe is able to directly measure plasma potential in a certain range of plasma parameters even though its current-voltage characteristic is not symmetric, which is in contradiction with the simplified theory for ball-pen probe. Powered by TCPDF (www.tcpdf.org)
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Studium turbulence plazmatu tokamaku pomocí reciprokých sond
Ondáč, Peter ; Horáček, Jan (advisor) ; Komm, Michael (referee)
This thesis deals with the study of turbulence in tokamak plasma and im- provement of an computer model ESEL. The first chapter deals with the theory related to the study of turbulence in the plasma. For the study of these tur- bulences the results of the probe measurements on the ASDEX Upgrade and COMPASS tokamak and model results from a computer model of the turbulent ESEL are used. The second chapter describes the used probes and the third chapter describes the model ESEL. Contribution of the work is mainly in the fourth and fifth chapter, which summarize the results of the comparisons be- tween the experimental data and model ESEL. The sixth chapter summarizes the most important conclusions from these comparisons. Some agreements and discrepancies were shown. One of the main results of the thesis is the impor- tance of one extra term in one governing equation of the ESEL, which means its improvement. However at present the ESEL is still not able to fully describe the tokamak plasma boundary. 1
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Automatic analysis of videokymographic images by means of higher-level features
Zita, Aleš ; Zitová, Barbara (advisor) ; Horáček, Jan (referee)
Human voice diagnosis is a complicated problem, even nowadays. The reason is poor access to the body itself and the high frequencies of vocal fold vibrations. One of the clinically available imaging methods to address these problems is Videokymography - a technology for capturing the vocal fold vibrations using a special line CCD camera. Individual lines stacked on top of each other form videokymographic recording. Videokymographic images are suitable for automatic characteristics extraction, therefore helping to reduce the laryngologist workload. For this purpose, the set of such methods is being developed in the Department of Image Processing in the Institute of Information Theory and Automation of the Academy of Science of Czech Republic. The ventricular band position and shape determination is one of the important, but difficult, tasks. The aim of this thesis is to propose new method of automatic detection of ventricular band on videokymographic recording using digital image processing techniques.
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Realtime library for procedural generation and rendering of terrains
Kahoun, Martin ; Horáček, Jan (advisor) ; Šik, Martin (referee)
Techniques for procedural generation of the graphics content have seen widespread use in multimedia over the past thirty years. It is still an active area of research with many applications in 3D modeling software, video games, and films. This thesis focuses on algorithmic generation of virtual terrains in real-time and their real-time visualization. We provide an overview of available approaches and present an extendable library for procedural terrain synthesis. Powered by TCPDF (www.tcpdf.org)
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CCTV system controller including motion-detection feature
Wirth, Michal ; Horáček, Jan (advisor) ; Dupej, Ján (referee)
The object of this work is to design and implement an application for managing a smaller surveillance system. There are analyzed several ways of it's possible arrangement. After then an appropriate application's architecture is designed based on discovered facts. Implemented system is introduced from user's point of view and also in a more technical sense. There is also a research of algorithms for real-time detection of moving objects within static scenes. Introduced ones are implemented, measured for their efficiency and compared with each other.
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