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Management of Undo/Redo Operations in Complex Environments
Jakubec, Karel ; Holubová, Irena (advisor) ; Lokoč, Jakub (referee)
During past thirty years, several models for non-linear undo models have been presented, but almost none solves undoing and redoing actions in environments, where multiple history buffers are involved and when there are causal dependencies among separate actions. This thesis focuses on developing a new model, which allows a user to select any action from any history buffer. The key part of the model is a smart command design and undo manager, which searches for dependencies and offers possible solutions to the user. The results are presented in the context of the DaemonX framework.
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The Support of XML Technologies in Oracle DB, IBM DB2 and Microsoft SQL Server
Hazaran, Elina ; Holubová, Irena (advisor) ; Lokoč, Jakub (referee)
The aim of this thesis is to perform an all-round comparison analysis of XML technologies support in three database systems: Oracle DB, IBM DB2 and SQL Server. It includes a theoretical technologies description and their comparison analysis, along with implemented software which is designed to run experiments by querying XML data using XQuery, SQL/XML technologies and XMark benchmark. It provides the comparison of database performances based on different storage methods, create time comparison statistics, export results to a text file and store the history of previous results. The main part of the work is the demonstration of several experiments run and a detailed analysis of the database performances based on the obtained results.
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Tree-based indexing methods for similarity search in metric and nonmetric spaces
Lokoč, Jakub ; Skopal, Tomáš (advisor) ; Dohnal, Vlastislav (referee) ; Patella, Marco (referee)
The M-tree is a well-known indexing method enabling efficient similarity search in metric spaces. Although the M-tree is an aging method nowadays, we believe it still offers an undiscovered potential. We present several approaches and directions that show how the original M-tree algorithms and structure can be improved. To allow more efficient query processing by the M-tree, we propose several new methods of (parallel) M-tree construction that achieve more compact M-tree hierarchies and preserve acceptable construction cost. We also demonstrate that the M-tree can be simply extended to a new indexing method - the NM-tree, which allows efficient nonmetric similarity search by use of the TriGen algorithm. All these experimentally verified improvements show that the M-tree can still be regarded as an important dynamic metric access method suitable for management of large collections of unstructured data. Moreover, all the improvements can be further adopted by M-tree descendants (e.g. the PM-tree), so that the results presented in this thesis open the door for future research in this area.
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Tree-based indexing methods for similarity search in metric and nonmetric spaces
Lokoč, Jakub
Title: Tree-based Indexing Methods for Similarity Search in Metric and Nonmetric Spaces Author: Mgr. Jakub Lokoč Department: Department of Software Engineering Faculty of Mathematics and Physics Charles University in Prague Supervisor: Doc. RNDr. Tomáš Skopal, Ph.D. Author's e-mail address: lokoc@ksi.mff.cuni.cz Supervisor's e-mail address: skopal@ksi.mff.cuni.cz Abstract: The M-tree is a well-known indexing method enabling efficient similarity search in metric spaces. Although the M-tree is an aging method nowadays, we believe it still offers an undiscovered potential. We present sev- eral approaches and directions that show how the original M-tree algorithms and structure can be improved. To allow more efficient query processing by the M-tree, we propose several new methods of (parallel) M-tree construction that achieve more compact M-tree hierarchies and preserve acceptable con- struction cost. We also demonstrate that the M-tree can be simply extended to a new indexing method - the NM-tree, which allows efficient nonmetric similarity search by use of the TriGen algorithm. All these experimentally verified improvements show that the M-tree can still be regarded as an im- portant dynamic metric access method suitable for management of large collections of unstructured data. Moreover, all the improvements can be...
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External Metric Hashing using the D-index
Jakl, Jiří ; Lokoč, Jakub (referee) ; Skopal, Tomáš (advisor)
The goal of this work was to implement recently presented data structure D-Index, to investigate behaviour of this metric access method and to compare its eciency with other indexing methods. As reference, M-Tree, PM-Tree and LAESA (approximated as PM-Tree with leaf pivots only) indexing methods were chosen. Performance measurements and comparison were done on various types of data with dierent distribution of distances.In this work, the D-Index structure was designed to support automatic build up of the index according to initial parameter setup and to allow dynamic insertion as well. Beside implementation of D-Index, an investigation of features of this indexing method was done. To achieve exibility and sucient performance of the solution, great eort was put on optimization and object realization. This allowed testing new ideas for choosing internal parameters and obtaining relevant results from measuring of investigated methods. The common principles (based on properties of metric spaces) of metric access methods were presented as part of their description. This work covered selected metric functions, several pivot selections and some aws of metric access methods.
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Modular system for managing web contents
Kulman, Igor ; Lokoč, Jakub (referee) ; Chrpa, Lukáš (advisor)
Modular web content management system (thereinafter ModularCMS) offers the users an easy and simple way to create an manage their own website, from a simple personal presentation to complex and extensive company web. ModularCMS puts the main afford on the simplicity of user and programming interface, separating itself from other existing CMSs. The simplicity of user inteface maens, taht if an end user orderes an web presentation based on this CMS, atfer its deployment, he will be able to manage the content and do all the other actions he may need very easy and quickly. The architecture of MudularCMS is modular, it could be extended with other functions a project may need by programming new moduls.
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Programming of drivers of external devices and data evaluation in C++
Kaščák, Kamil ; Lokoč, Jakub (referee) ; Kodyš, Peter (advisor)
In the present work we study current status of drivers for external devices in clean room in Institute of Particle and Nuclear Physics. In this work we analyse existing software and create a new driver for communication through RS232 port. Work studies various possibilities of serial communication in Windows and Linux and creates possible design for driver, which is based on creating universal layer for supplying communication between user programs and external devices. Work describes important steps of implementation in both operating systems. Next part consists of user documentation for created software. This documentation focuses on di erences of usage in Windows and Linux. At the end work shows report from testing software with real devices and gives advices, which should programmer follows when creating similar software solution.
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Communication with external devices in laboratory
Vachna, Michal ; Lokoč, Jakub (referee) ; Kodyš, Peter (advisor)
In the present work the goal is to map present circumstances of computer infrastructure in the physical laboratory, examine the demands and problems at work in the laboratory such as data backup, remote control, disk space sharing, access organization of processes to external devices, version control of measuring application development, running processes on remote hosts. Assess existing solutions, consider the possibility of improvements and propose new solutions appropriate to the needs of the laboratory. As far as possible, in regard to the current operations of the laboratory, implement solutions to selected problems and requirements. The work has to be methodical material and guide for further development of the laboratory in the coming years.
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Using Neural Networks in the Hierachical Routing
Straka, Martin ; Lokoč, Jakub (referee) ; Štanclová, Jana (advisor)
The objective of the diploma thesis is to show possible utilization of the neural networks for the partitioning needs of the hierarchical routing algorithm. The work proposes a hierarchical approach, which can be useful for the optimal path searching process. We focus on the application of several neural network models to extract hierarchical information from the transportation network data. Introduced models are based on the energy minimization principle and we demonstrate an employment of the deterministic annealing methods (MFA) as quite ambitious in the partitioning process. The experimental part of this work makes use of our findings and propose several suggestions on the proper parametrization of employed neural network models. In the experimental tests, we demonstrate capabilities of the MFA to provide a partitioning task also in case of lack of the global information.
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