National Repository of Grey Literature 258 records found  beginprevious159 - 168nextend  jump to record: Search took 0.00 seconds. 
Compression of biological sequences
Šurín, Tomáš ; Mráz, František (advisor) ; Dvořák, Tomáš (referee)
Volumes of data obtained from the next generation sequencing platforms is growing faster than the available capacity of storage media. Sequencers mainly produce short reads of DNA. However, output of the sequencing machines also contains other information, for example information about read reliability/quality. This data must be archived even after successful complete genome assembly. Standard file format used for this type of data is format SAM (Sequence Alignment/Mapping Format) and its binary compressed version BAM. In this thesis we describe the construction of a better lossless compression scheme for compression of files in the SAM/BAM format. This compression scheme provides better compression ratios than the BAM format. In addition, random access to data in the compressed file is retained. Implementation of this compression scheme is platform independent and allows simple configuration of the compression process. Implementation also offers easy extensibility. Thanks to this, we will be able to respond to changes in current sequencing platforms as well as to changes in the SAM format.
The Screen of Laughter and Remembering: Cinematography and Post-Socialist Memory
Hladík, Radim ; Dvořák, Tomáš (advisor) ; Kusá, Zuzana (referee) ; Hanáková, Petra (referee)
THE SCREEN OF LAUGHTER AND REMEMBERING Collective Memory and Representations of State Socialism in Czech Cinematography This dissertation has very little to say about state socialism. Rather, it is a work about the memory of state socialism in the post-socialist Czech Republic, about the ways in which state socialism can be remembered in the present. From the perspective of collective memory, "it is not only the ancien regime that produced revolution, but in some respect the revolution produced the ancient regime, giving it a shape, a sense of closure" (Boym 2001, xvi). And there are indeed many, often conflicted modes of remembering this particular past. Françoise Mayer, for example, has identified several distinct types of remembering the "communism" in Czech society (Mayer, 2009). And her list is by no means exhaustive. At the centre of this treatise is the Czech post-socialist cinema. My dissertation thesis was prompted by the question of how cinematic representations bear on the collective memory of state socialism in the Czech Republic. . In the first chapter, I explore how cinema represents the past in comparison to historiography. In my work, it is evident that Czech cinema does not follow the epistemological criterion of referentiality that binds historians. A more important observation - and one...
Suffix tree construction with minimized branching
Bašista, Peter ; Dvořák, Tomáš (advisor) ; Kadlec, Rudolf (referee)
Suffix tree is a data structure which enables the performing of fast search-like operations on the text. In order to be used efficiently, it must be created quickly. In this thesis, we focus on the new kind of suffix link simulation called "minimized branching", which aims to increase the speed of suffix tree construction by reducing the number of branching operations. Our main goal is to present a comparison of the currently used methods for the suffix tree construction and to point out some advantages and disadvantages of the individual approaches. We introduce, implement and practically evaluate multiple variations of the standard McCreight's and Ukkonen's algorithms, as well as Partition and Write Only Top Down (PWOTD) algorithm, originally developed for disk-based construction. Our main result is the integrated description and implementation of these algorithms, which are both well-suited to be further built upon. We also present a simple recommendations on when it is advisable to use a particular algorithm's variation and why.
Gray code based bitmap compression
Škorvaga, David ; Dvořák, Tomáš (advisor) ; Gregor, Petr (referee)
This thesis deals with a compression of bitmap indexes. Bitmap indexes may be reduced through specialized algorithms which look for long runs of identical bits. To improve the compression ratio, it is useful to reorder the rows of the index. Even though the problem of optimal reordering is NP-hard, there are efficient heuristics which reorder the index in polynominal time. Recent results suggest that Gray code based sorting provides an effective alternative to the classical lexicographical sorting. In this thesis, we replace the classical Gray code with a novel construction which generates a compressed Gray code. We describe this construction in detail and use both real-life and randomly generated datasets to test whether the novel construction is more efficient than the classical one when used in the WAH compression scheme.
Compact directed acyclic word graph in a sliding window
Filip, Ondřej ; Dvořák, Tomáš (advisor) ; Senft, Martin (referee)
Compact directed acyclic word graph (CDAWG) is the space-efficient version of a text-indexing data structure called suffix tree. The goal of this work is an implementation and comparison of algorithms constructing CDAWG for text in a sliding window. Sliding window is favorable in cases when the index structure cannot be kept in memory for the whole indexed data. One exact move of the sliding window may be performed in linear time with respect to the length of the window. An approximative algorithm requiring only amortized constant time per one move has been developed, too. However, in this thesis, the correctness of this algorithm has been disproved.
Word order reconstruction
Dvořák, Tomáš ; Vidová Hladká, Barbora (advisor) ; Mírovský, Jiří (referee)
A word order reconstruction is a re-arrangement of words to get a gramma- tically correct sentence. It is a very useful task for the applications of natural language processing, machine translation, speech recognition or construction artificial communication partners. We present a corpus-based approach to the task of word order reconstruction. We use two methods: morfological and syntactical method. Both methods use output from the external module. This approach is designed independently on the application where the word order reconstruction can help improve overall performance. Czech and English will be used as the object language. 1
Changes of children's status in society: disappearance of childhood or childhood innocence?
Papoušková, Kristina ; Balon, Jan (advisor) ; Dvořák, Tomáš (referee)
My bachelor work is focused on the topic of childhood, namely its development and change in society. I introduce here the discipline of sociology of childhood - range of its interest, background of its progress and notable authors. I'd like to prove that childhood isn't only a period of time in life. I research infancy as social entity, in this context it is possible to compare childhood to social construct such as gender or social class. I define possible forms of infancy including for example the topic of disappearance of childhood. I try to emphasize that infancy wasn't always included in the same way in society. Last but not least I try to deconstruct the myth of innocent childhood, which is typical for Western culture. Apart from the theoretically oriented part the work also includes empiric section, which analyses infancy of three generations of women, who lived their childhood in different periods of 20th century in Czechoslovakia. In this analysis I concentrate on infancy in context of social changes and in relation to effect of educational institutions or child collective on children. I aim to describe disappearing infancy and the myth of child innocence.
Unbound images: archeology of (Czech) virtual space
Svatoňová, Kateřina ; Hanáková, Petra (advisor) ; Vojvodík, Josef (referee) ; Dvořák, Tomáš (referee)
The thesis does not include an abstract in English. The thesis does not include an abstract in English. The thesis does not include an abstract in English. The thesis does not include an abstract in English. The thesis does not include an abstract in English. The thesis does not include an abstract in English.
DJ - postmodern phenomenon
Marcinovová, Ivana ; Tuček, Milan (advisor) ; Dvořák, Tomáš (referee)
The thesis concerns identity construction of DJs. It's goal is to find out, how DJs talk about the art of DJing, how they reflect the technical evolution and how they operate under the current conditions of informational chaos. The Qualitative research was led in the form of semi-structured interviews with notable Czech and British DJs. The initial theme frame is particularly formed by theoretical concepts of contemporary authors, dedicated to principals of the postmodern art. The main intention of this text is to introduce a significant cultural phenomenon which has not been identified by the Czech sociology yet.
Hierarchical compression
Kreibichová, Lenka ; Lánský, Jan (advisor) ; Dvořák, Tomáš (referee)
The most of existing text compression methods is based on the same base concept. First the Input text is divided into sequence of text units. These text units cat be single symbols, syllables or words. When compressing large text files, searching for redundancies over longer text units is usually more effective than searching over the shorter ones. But if we choose words as base units we cannot anymore catch redundancies over symbols and syllables. In this paper we propose a new text compression method called Hierarchical compresssion. It constructs hierarchical grammar to store redundancies over syllables, words and upper levels of text. The code of the text then consists of code of this grammer. We proposed a strategy for constructing hierarchical grammar for concrete input text and we proposed an effective way how to encode it. Above mentioned our proposed method is compared with some other common methods of text compression.

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