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Relační přístup k indexaci
Prukl, Antonín ; Pokorný, Jaroslav (advisor) ; Skopal, Tomáš (referee)
In order to achieve efficient evaluation of SQL queries, database systems provide its users with set of integrated index access methods. When a new access method is required for various reasons, one of the possibilities to implement such method in a relational DBMS is the way of exploiting relational tables of given database system. This approach does not involve any internal changes of database system kernel and thus it is available to all developers even when the target DBMS is not distributed as an open source. In the terms of extensible database architecture, only the availability to extend existing DBMS with a new data type is required. In this work, UB-Tree index has been integrated into Oracle DBMS in such way. Index related tables have been designed in two different ways and four alternatives to evaluate relevant queries have been proposed and studied. Finally, several experiments have been done to compare performance of an access method implemented via the relational approach and a native kernel integration of the same method.
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Webmining
Ljubopytnov, Vladimír ; Pokorný, Jaroslav (advisor) ; Húsek, Dušan (referee)
This thesis focuses on mapping latest knowledge in the area of web mining with emphasis on document clustering. Most attention is given to the DOC projective clustering algorithm, a modification is presented for data with weighted dimensions. Algorithm is used for web search engine result clustering. Also, a clustering package with Google interface and phrase evaluation tool is implemented.
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Abilities and importance long-term cultivation embryonic cells from different species of animals
Houdek, Zbyněk ; Vožeh, František (advisor) ; Bártová, Eva (referee) ; Pokorný, Jaroslav (referee)
Embryonic cells inside the blastocyst, which divide and differentiate into cells of all tissues of organism, are called embryonic stem (ES) cells. Using the ES cells for transplantations is one the potential ways in regenerative medicine. The present study deals with two different lines of mouse pluripotent cells: embryonic carcinoma (EC) cells line P19 and ES cells line D3. The in vitro cultivation was performed in basal cultivation medium with fetal bovine serum (FBS) and in addition of leukemia inhibitory factor (LIF) in case of ES cells. The neurodifferentiation was induced by medium without FBS and without LIF in case of ES cells and supported by retinoic acid in case of P19 cells and embryoid bodies cultivation in case of ES cells. Pluripotency and neurodifferentiation of the cells were confirmed by presence of molecular markers of pluripotency and neurodifferentiation in both lines in nondifferentiated and differentiated states. Mouse EC P19 cells were transfected by gene for green fluorescent protein (GFP) and used for transplantation in cerebellum of wild type (WT) and Lurcher (Lc) mutant mice. Nondifferentiated cells (P19) and neuroprogenitors (NPG) derived from these cells were used. The study followed the survival, morphology and localization of the grafts. The survival of both types of GFP...
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Methods for effective querying of RDF data
Dokulil, Jiří ; Pokorný, Jaroslav (advisor) ; Svátek, Vojtěch (referee) ; Benczúr, András (referee)
The RDF is one of the basic building blocks of the Semantic Web. It is a low-level data format intended to be used by software developers to create semantic-enabled applications. The ability to place and efficiently evaluate queries is key in this scenario. In this thesis, we approach the problem of RDF querying from three different angles. First, we present an RDF visualization tool, that the developer can use to get an idea about the structure and contents of the data. Second, we have designed extensions of the XQuery language that allow us to give it RDF handling capabilities. The main contribution is introduction of records into the language. Third, to cover query evaluation, we have designed the Bobox parallel framework, which can be used to simplify development of parallel data processing applications. It provides both task and data parallelism.
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Methods for finding best answer with different user preferences
Eckhardt, Alan ; Vojtáš, Peter (advisor) ; Pokorný, Jaroslav (referee)
User preferences are one of new aspects in informatics, e.g. in domain of semantic web. This work tries to cover the whole problematic of user preferences, their modeling, various aspects of generating user preferences and their evaluation. It also studies the area of group decision and finding answer that suits all members of group. Next part follows the paper of Ronald Fagin, Amnon Lotem, Moni Naor about the top-k algorithm. The new independent system for the top-k algorithm is presented, some implementations of this algorithm are tested and the influence of modules of algorithm on the speed and the number of rows are studied.
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XSLT Implementation in Relational Database Environment
Kmoch, Ondřej ; Pokorný, Jaroslav (advisor) ; Holubová, Irena (referee)
XML is widely used format for storing all kinds of data and XSLT standard represents a standardized way, how to transform a XML document to a di fferent structure. Many XSLT implementation has been introduced, but the most of them uses an in-memory representation of the transformed XML document. The implementation done in this thesis uses the relational database engine to store processed document and takes advantages of SQL to evaluate XPath expressions used by XSLT. First, importing source XML document into the generic relational mapping is described. For processing XPath expressions, the XPath to SQL convertor is introduced. Lastly, the processing of XSLT stylesheets by relational database engine is shown.
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Conceptual Modeling for XML
Nečaský, Martin ; Pokorný, Jaroslav (advisor) ; Krátký, Michal (referee) ; Thalheim, Bernhardt (referee)
XML is a popular format for data representation. As the amount of data represented in XML grows, it is necessary to concentrate on the process of modeling XML schemes of the XML representations. However, modeling the XML schemes on the level f XML schema languages, such as XML Schema, has some drawbacks. A natural idea to improve this situation is to model the XML schemes rst on the conceptual level. It is motivated by the world of relational databases where we also start modeling the data fi rst on the conceptual level. In this thesis we focus on conceptual modeling for XML. We start with a motivating example to point out to several problems that can arise when using only XML schema languages for modeling XML schemes. We discuss how modeling the data rst on the conceptual level can help. We also show that conceptual modeling for XML has some speci cs that should be taken into account by a conceptual model for XML. Mainly, we show that it is necessary to separate the conceptual modeling process to two parts. First, we need to model the data independently of its representation in XML. Second, we need to model how the data is represented in di erent types of XML documents. In the next step, we analyze in detail existing approaches to conceptual modeling for XML and show their limitations. In the main part of...
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C-store: storing relational data by columns
Částek, Petr ; Pokorný, Jaroslav (advisor) ; Žemlička, Michal (referee)
Non standard approach to the implementation of relational databases this work implements a database system storing the data by columns instead of rows. It is based on the C Store system design and is limited only to the fundamental solution issues. Two areas are being solved: the initial creation of the database, including import of static database data from another source, and querying. The database does not store the data in tables but in projections groups of columns of the same length. By using this database layout it is possible to evaluate queries faster than with database storing by rows as the database engine does not have to read irrelevant columns. Querying is allowed by providing an execution plan consisting of the C Store query operators that work with columns or projections. Composition of these operators can replace queries in SQL notation. This work sets the rules of behavior of various operators, implements these operators and also mentions the optimization of the execution plan. The optimization also includes a C Store system extension providing direct access to data items, which in some cases radically reduce the amount of IO operations. The practical output of the work is a library that provides a programming interface for database access and manipulation.
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