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Dictionary Methods of Data Compression
Černičko, Sergij ; Polok, Lukáš (referee) ; Bařina, David (advisor)
The aim of this thesis is to analyse dictionary methods of data compression and their characteristics. The work is focused on and hands out detail overview of dictionary methods LZ77, LZ78, LZSS, LZW, DEFLATE and LZX. Principles of these methods and also general theory of compression is described. In conclusion all methods are tested and results analyzed.
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Implementation of Statistical Compression Methods
Ftorek, Peter ; Polok, Lukáš (referee) ; Bařina, David (advisor)
The aim of this thesis is to describe statistical methods for data compression. Introduction covers theoretical minimum of data compression. Center of the work is about description of each method and implementation of Burrows-Wheeler compression algorithm in C programming language. It contains test results of each method and their evaluation.
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Lossless Data Compression for IP Networks
Pánek, Richard ; Kajan, Michal (referee) ; Korček, Pavol (advisor)
This bachelor's thesis deals with data compression methods in IP networks. The LZW compression algorithm and its history is described more in detail. This algorithm is tested on the di erent types of IP tracffic. It is shown that depending on the traffic type it is possible to reduce data to 70% of its original size. As the final implementation of the LZW algorithm is intented for use in the FPGA the results from high level synthesis (from C to VHDL language) are fi nally described.
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Compression Methods Based on Context Modelling
Krupička, Matúš ; Drábek, Vladimír (referee) ; Bařina, David (advisor)
This thesis is dedicated to analysis of context-based compression methods, their characteristics and possibilities of their usage. Thesis focuses on and hands out detail overview of statistical method PPM (prediction by partial matching). Program design of this method is described as well as the implementation. Lastly, also the outcomes of this program are compared with already existing implementations of data compression.
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Compression Methods Based on Context Modelling
Kozák, Filip ; Drábek, Vladimír (referee) ; Bařina, David (advisor)
Purpose of this thesis is to describe the context-based compression methods and their application to multimedia data. There is described the principle of arithmetic coding and prediction by partial matching method, including creation of the probability model. There are also described multimedia data and the basic principles of their compression. The next section presents compression methods, that I implemented at work and their results.
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Implementation of Statistical Compression Methods
Beněk, Tomáš ; Polok, Lukáš (referee) ; Bařina, David (advisor)
This thesis deals with the statistical compression methods. This work describes basic theoretical introduction to the data compression and the most important representatives of statistical methods. There is also described compression process based on the Burrows-Wheeler algorithm, which is implemented in the form of portable library in C++ programming language. This work compares effectiveness of each method on suitable data corpus, which contains various data types and according to achieved results discusses suitability of usage of methods and possible improvements.
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ECG Signal Transmission via Ethernet
Bayerová, Zuzana ; Provazník, Ivo (referee) ; Sekora, Jiří (advisor)
The semestral thesis describes ECG signal compression methods designed to modify the data for transmission via communication channels. The thesis contains an introduction to Ethernet and explanation of communication in the network. The transport protocols TCP and UDP are discussed in more detail. In the practical part of the thesis was created two separate applications. The first application in the sender's computer opens a text file with the ECG signal. Loaded ECG signal is filtered by cascade of filters to eliminate interference. The resulting signal is displayed. A part of the application is the R wave detection, calculating the length of RR interval and heart rate. The application also allows to compress an ECG signal. ECG signal is sent via Ethernet network via UDP protocol for individual samples. Applications in the recipient's computer receives signal samples from the network. Recieved compressed data is reconstructed. The resulting ECG signal is displayed and there are again detected R waves, the length of RR intervals and sampling frequency are calculated.
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Uplatnění fraktálů v kompresi dat
Dušák, Petr ; Ivánek, Jiří (advisor) ; Palovský, Radomír (referee)
The mission of the Technology Transfer Programme Office is to increase impact on a society by transferring technologies developed by the European Space Agency. Method and Apparatus for compressing time series is a patented compression algorithm designed to be efficient as its purpose is to run on deep space probes or satellites. The algorithm is inspired by a method for fractal terrain generation, namely the midpoint displacement algorithm. This work introduces fractals, their application and modifying the patented algorithm, in order to achieve greater compression. The modification lies in modifying the displacement mechanism. The modified algorithm is capable of reducing data up to 25 %, compared to the patented algorithm. The modification made the algorithm less efficient. In large-scale test, performed on Rosetta spacecraft telemetry, the modified algorithm achieved around 5 % higher compression.
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