National Repository of Grey Literature 366 records found  previous11 - 20nextend  jump to record: Search took 0.00 seconds. 
Inference of an XML Schema with the Knowledge of XML Operations
Mikula, Mário ; Holubová, Irena (advisor) ; Svoboda, Martin (referee)
Recently, plenty of methods dealing with automatic inference of XML schema have been developed, however, most of them utilize XML documents as their only input. In this thesis we focus on extending inference by incorporating XML operations, in particular XQuery queries. We discuss how can XQuery queries help in improving the inference process and we propose an algorithm based on chosen improvements, extending an existing method of a key discovery, that can be integrated to methods inferring so-called initial grammar. By implementing it, we created the first solution of XML schema inference using XML documents along with XML operations.
Processing of Incorrect XML Data
Svoboda, Martin ; Holubová, Irena (advisor) ; Nečaský, Martin (referee)
XML documents and related technologies represent widely accepted standard for managing and exchanging semi-structured data. However, surprisingly high number of XML documents is affected by well-formedness errors, structural invalidity or data inconsistencies. The aim of this thesis is the analysis of existing approaches resulting to the proposal of a new correction framework. The introduced model involves repairs of elements and attributes with respect to single type tree grammars. Via the inspection of the state space of an automaton recognising regular expressions, we are always able to find all minimal repairs. These repairs are compactly represented by recursively nested multigraphs, which can be translated to particular sequences of edit operations altering data trees. We have proposed four particular algorithms and provided the prototype implementation supplemented with experimental results. The most efficient algorithm heuristically follows only perspective repair directions and avoids repeated computations using the caching mechanism.
Efficient Detection of XML Integrity Constraints
Švirec, Michal ; Holubová, Irena (advisor) ; Svoboda, Martin (referee)
Title: Efficient Detection of XML Integrity Constraints Author: Michal Švirec Department: Department of Software Engineering Supervisor: RNDr. Irena Mlýnková, Ph.D. Abstract: Knowledge of integrity constraints covered in XML data is an impor- tant aspect of efficient data processing. However, although integrity constraints are defined for the given data, it is a common phenomenon that data violate the predefined set of constraints. Therefore detection of these inconsistencies and consecutive repair has emerged. This work extends and refines recent approaches to repairing XML documents violating defined set of integrity constraints, specif- ically so-called functional dependencies. The work proposes the repair algorithm incorporating the weight model and also involve a user into the process of de- tection and subsequent application of appropriate repair of inconsistent XML documents. Experimental results are part of the work. Keywords: XML, functional dependency, functional dependencies violations, vi- olations repair
XML Query Adaptation
Polák, Marek ; Holubová, Irena (advisor) ; Malý, Jakub (referee)
In the presented work we study XML schema evolution, its types and impact on queries which are related on the particular schema. The thesis contains a review of existing approaches of this problem. The approach presented in this work shows a possible solution how to adapt related queries while schema evolves. The thesis contains a description of an algorithm which modies queries related to the evolved schema. Finally the work contains a number of exper- iments that verify proposal of the algorithms and show their advantages and disadvantages. 1
Vzájemný převod mezi XSEM PSM diagramy a jazykem Schematron
Benda, Soběslav ; Klímek, Jakub (advisor) ; Nečaský, Martin (referee)
In the present work we study possibilities in the area of automatic construction of Schematron schemas from a conceptual model for XML and possibilities in reverse-engineering of Schematron schemas. The work introduces the reader to conceptual schemas for XML and to rule-based validation of XML documents. Existing techniques for mutual conversions between XML schema languages and conceptual model are also included. The main part of the work is a design and implementation of a new method for deriving Schematron schemas from conceptual schemas for XML. This method allows to get XML schemas, which in some respects outperforms the possibilities of other popular schema languages.The work also discusses the issue of Schematron schema reverse-engineering and shows possibilities in the area and establishing basis for further research.
Inference of XML Integrity Constraints
Vitásek, Matej ; Holubová, Irena (advisor) ; Knap, Tomáš (referee)
In this work we expand upon the previous efforts to infer schema information from existing XML documents. We find the inference of structure to be sufficiently researched and focus further on integrity constraints. After briefly introducing some of them we turn our attention to ID/IDREF/IDREFS attributes in DTD. Building on the research by Barbosa and Menelzon (2003) we introduce a heuristic approach to the problem of finding an optimal ID set. The approach is evaluated and tuned in a wide range of experiments.
Profiling translation of conceptual schemas to XML schemas
Berka, Lukáš ; Nečaský, Martin (advisor) ; Holubová, Irena (referee)
In the present work we analyze the algorithm that was introduced in [4]. The algorithm performs a translation of a conceptual schema to an XML schema expressed in the XML Schema language. We look for limitations of the algorithm and try to discover parameters that can be potentially used to influence its behavior. We propose solutions to the most serious limitations. Also, we introduce a concept of a translation profiling. The concept is based on a configuration that contains a set of parameters. We modify the algorithm to use the user requirements specified in the configuration. Thanks to the improvements, the new algorithm works with the concept of XML Namespaces, uses XML Schema designs and also, focuses on an elimination of redundancy. The elimination of redundancy in an output of the algorithm is an important part of this work and we create a formal model that helps us to solve this task.
Mining XML Integrity Constraints
Fajt, Stanislav ; Nečaský, Martin (advisor) ; Svoboda, Martin (referee)
The most important integrity constraints in XML are primary keys and foreign keys. In general, keys are essential in understanding both the structure and properties of data. They provide an instrument by which va- lues from a given set of attributes uniquely identify tuples in a database. As a result, keys are important to main database operations. Since XML beco- mes lingua franca for data exchange on the web, it is widely accepted as a model of real world data. Because XML documents in general can appear in any semi-structured form, structural constraints (including keys) are often imposed on the data that are to be modified or processed These constra- ints are formally defined in a schema.Unfortunately, in spite of the obvious advantages, the presence of a schema is not mandatory and many XML do- cuments are not joined with any. Consequently, no integrity constratins are specified in those documents, neither. This thesis is mainly focused on the inference of primary and foreign keys from XML documents. 1
Automatic Generation of Synthetic XML Documents
Betík, Roman ; Holubová, Irena (advisor) ; Svoboda, Martin (referee)
The aim of this thesis is to research the current possibilities and limitations of automatic generation of synthetic XML and JSON documents used in the area of Big Data. The first part of the work discusses the properties of the most used XML data generators, Big Data and JSON generators and compares them. The next part of the thesis proposes an algorithm for data generation of semistructured data. The main focus of the algorithm is on the parallel execution of the generation process while preserving the ability to control the contents of the generated documents. The data generator can also use samples of real data in the generation of the synthetic data and is also capable of automatic creation of simple references between JSON documents. The last part of the thesis provides the results of experiments with the data generator exploited for the purpose of testing database MongoDB, describes its added value and compares it to other solutions. Powered by TCPDF (www.tcpdf.org)
Comparison of Tree Edit Distance Algorithms
Ivkin, Egor ; Nečaský, Martin (advisor) ; Lokoč, Jakub (referee)
The aim of this thesis is the comparison of the Tree Edit Distance methods, in the context of detecting structural similarity between two XML Schema documents. The methods search the minimum number of edit operations leading from one tree to another. We have analysed and implemented a wide range of the existing tree edit distance approaches. It is important to understand that the distance computed by the algorithms is affected by the set of used edit operations, therefore the strength in detecting XML Schema similarity differs in each approach. The first part of this work contains the description of the used approaches and necessary notations. The second part provides implementation details and analysis of the described methods, which consists of theoretical comparison and empirical evaluation on real and synthetic xml data. The resulting implementation is available in the form of Java SE application.

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