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Lossless JPEG compression
Ondruš, Jan ; Lánský, Jan (advisor) ; Žemlička, Michal (referee)
JPEG is a commonly used method of compression for photographic images. It consists of lossy and lossless part. Static Huffman coding is a last step. We can replace this step using advanced techniques and arithmetic coding. In this work we introduce method used for additional compression JPEG files (files in JFIF format) saved in baseline mode. Partial decompression is a general way we can use in this case. We invert only last lossless steps of JPEG compression algorithm. Compressed file is transformed into array of quantized DCT coefficients. We designed algorithm for prediction of the DCT coefficients. It returns particular linear combination of previous coded coefficients in current and neighbouring blocks for each from 64 coefficients in block matrix. We show how this prediction can improve efficiency of compression of JPEG files using Context Mixing algorithm implemented in PAQ8 by Matt Mahoney. Specific implementation is described and its compression ratio is compared with existing methods and applications for further lossless JPEG images compression.
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LZPXj - improvement of LZP algorithm
Ondruš, Jan ; Lánský, Jan (advisor) ; Dvořák, Tomáš (referee)
LZP algorithm is one of algorithms designed for text compression. It is based on ideas published in paper "A Universal Algorithm for Sequential Data Compression" by Ziv and Lempel. The author of method LZP itself is Charles Bloom who proposed general scheme and his implementations. The aim of present work is continue progress of existing implementations of LZP algorithm and designing software for file compression. Some original ideas are proposed and included helping achieve e®ecient compression for various kind of data. LZPXj compressor is better for common files containing text, multimedia or executables. Part of this work is apart from description of improved algorithm also tests and comprehensions with some existing compression programs.
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Exhaustion of Copyright in Computer Programs
Ondruš, Jan ; Dobřichovský, Tomáš (advisor) ; Holcová, Irena (referee)
(EN) The aim of this thesis is to provide an analysis of the principle of exhaustion of rights especially to computer programs in the comparative context of the legal regulation in the EU and US. The issue of exhaustion of rights to computer programs became a topical problem after the decision of the Court of Justice of the European Union (CJEU) in case UsedSoft v. Oracle, when the CJEU ruled that the principle of exhaustion of rights is applicable not only for sale of computer programs on tangible media such as CD/DVD, but also for distribution of computer programs in digital form via Internet. This decision, however, became widely criticized by legal experts, since CJEU accented rather economic arguments in favor of this principle than the European legal regulations and international conventions. Certain problematic aspects were also demonstrated in the decision of US court in case Capitol Records v. ReDigi, in which the court persuasively summarized legal and technical reasons why the principle of exhaustion of rights cannot be applicable for the sale of digital files distributed via Internet in the context of current legal regulation. In the first part of my theses, I deal with the term "computer program" as a subject matter of law, and as a subject of protection by copyright law. The second...
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The function of an arbitrator in international arbitration
Ondruš, Jan ; Pauknerová, Monika (advisor) ; Kučera, Zdeněk (referee)
The Function of an Arbitrator in International Arbitration (abstract) Jan Ondruš With increasing importance of the international arbitration as a resolution mechanism for disputes arising from international commerce, the role of international arbitrators becomes also more important. The trials to find uniform theoretic explanation of all issues related to the function of arbitrator are however unsuccessful, due to theoretical differences between different legal cultures. The author of this thesis tries to analyze these different approaches and focus more on the function of arbitrator in international arbitration, where on one side there is a clash between the above mentioned different approaches, but on the other hand the established system facilitates mutual recognition of arbitral awards from a state with different legal regulation of arbitration. The author focuses primarily on the explanation of the term international arbitration as mechanism of dispute resolution. Secondly, the author analyzed requirements, the mostly often imposed on potential arbitrators by state law, by arbitral institutions and by parties and also different mechanisms of establishing the function of arbitrators. After this analysis the author elaborates on the relationship, established between the parties and the arbitrator in the...
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Lossless JPEG compression
Ondruš, Jan ; Žemlička, Michal (referee) ; Lánský, Jan (advisor)
JPEG is a commonly used method of compression for photographic images. It consists of lossy and lossless part. Static Huffman coding is a last step. We can replace this step using advanced techniques and arithmetic coding. In this work we introduce method used for additional compression JPEG files (files in JFIF format) saved in baseline mode. Partial decompression is a general way we can use in this case. We invert only last lossless steps of JPEG compression algorithm. Compressed file is transformed into array of quantized DCT coefficients. We designed algorithm for prediction of the DCT coefficients. It returns particular linear combination of previous coded coefficients in current and neighbouring blocks for each from 64 coefficients in block matrix. We show how this prediction can improve efficiency of compression of JPEG files using Context Mixing algorithm implemented in PAQ8 by Matt Mahoney. Specific implementation is described and its compression ratio is compared with existing methods and applications for further lossless JPEG images compression.
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LZPXj - improvement of LZP algorithm
Ondruš, Jan ; Dvořák, Tomáš (referee) ; Lánský, Jan (advisor)
LZP algorithm is one of algorithms designed for text compression. It is based on ideas published in paper "A Universal Algorithm for Sequential Data Compression" by Ziv and Lempel. The author of method LZP itself is Charles Bloom who proposed general scheme and his implementations. The aim of present work is continue progress of existing implementations of LZP algorithm and designing software for file compression. Some original ideas are proposed and included helping achieve e®ecient compression for various kind of data. LZPXj compressor is better for common files containing text, multimedia or executables. Part of this work is apart from description of improved algorithm also tests and comprehensions with some existing compression programs.
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