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Digital Transducer Array Loudspeakers System
Ležák, Petr ; Káňa, Ladislav (referee) ; Schimmel, Jiří (advisor)
This thesis discusses loudspeakers with a direct D/A conversion, possibilities of their technical solution and construction. It analyses classic conversion of digital signal to analog with D/A converters, amplifiers and loudspeakers and possibilities of its replacement by loudspeakers with a direct D/A conversion. The main part of thesis is devoted to design of a loudspeaker with a direct D/A conversion and a proper exciter for it. The exciter is designed from a block diagram to a specific electric circuit and printed circuit boards. The loudspeaker system is designed as well and the results of its simulations are included in this thesis. The device was constructed and tested. The program which generates digital harmonic signal on parallel port was written and electric and acoustic properties of the device was measured and discussed.
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Signal processing using parallel mathematical operations
Polášek, Jaromír ; Ležák, Petr (referee) ; Mžourek, Zdeněk (advisor)
This Bachelor thesis deals with the acceleration of function calculations, using parallel computing mediated by NVDIA graphics cards via CUDA technology. The theoretical part describes the general principles of parallel computing and the basic characteristics and parameters of graphics cards NVDIA. The theoretical part also deals with basic principles of CUDA technology. End of the theoretical part focuses on FFTW and cuFFT libraries. The practical part deals with the comparison of the performance between GPU and CPU functions filter2D and Canny and practical possibilities of accelerating fast convolution calculation. The practical part also describes sample code that was used to compare the performance between GPU and CPU. The results of this program are then plotted and evaluated.
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Random number generator
Križan, Viliam ; Burda, Karel (referee) ; Ležák, Petr (advisor)
This master thesis deals with a generation of random numbers and Fortuna generator implementation in Java language. In the first part the theoretical familiarization to the issues is introduced. Various entropy sources like mouse movement, keyboard typing, microphone and web camera noise are described and analysed. The analysis focuses on randomness, usability and volume of gathered data. Also the Fortuna random number generator is described from the theoretical view. Object analysis and implementation details are described in the last chapter of the document.
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Signal processing using parallel mathematical operations
Polášek, Jaromír ; Ležák, Petr (referee) ; Mžourek, Zdeněk (advisor)
This Bachelor thesis deals with the acceleration of function calculations, using parallel computing mediated by NVDIA graphics cards via CUDA technology. The theoretical part describes the general principles of parallel computing and the basic characteristics and parameters of graphics cards NVDIA. The theoretical part also deals with basic principles of CUDA technology. End of the theoretical part focuses on FFTW and cuFFT libraries. The practical part deals with the comparison of the performance between GPU and CPU functions filter2D and Canny and practical possibilities of accelerating fast convolution calculation. The practical part also describes sample code that was used to compare the performance between GPU and CPU. The results of this program are then plotted and evaluated.
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Low-level data reading from computer data storages
Šalko, Jaroslav ; Ležák, Petr (referee) ; Burda, Karel (advisor)
The following work is topically focusing on data restore of selected memory devices. It could be divided into two theoretical parts and one practical. The first part consist explanation of these memory media’s structure, the mechanism of their storage and also how operating system approaches these data. This relates also to a file system, which is among with its most commonly used types described there as well. In the second theoretical part the study focuses on the storage damage problematics. Various types of damage are shown and I examine how we could approach them. The work concentrates on possibilities which owners of the damaged storage media have with an emphasis on specialized companies. Therefore the study contains brief information of four selected domestic companies which are offering data restore on the Czech market. The complete list of services, which these companies offer to their customers, is shown in the chart found by the end of chapter. The second option in order of solving media damage problems are freeware programmes. On the basis of an internet poll dealing with the topic „best programmes for data restore“, I have chosen three programmes to be examined. The examination consisted of uploading certain files on the media storage which was formated by high level method afterwards. Through these three programmes I tried to restore the lost data. The results are included in a chart found by the end of each sub-chapter. The practical part of my work deals with linux program for data restore DDrescue. My effort consists of developing and creating an user friendly interface with intuitive manipulation of this helpful tool. My goal is thus spreading this program into the public and providing them simple tool for efficient low-level data restore.
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Client-server password manager
Myška, Vojtěch ; Burda, Karel (referee) ; Ležák, Petr (advisor)
This bachelor thesis deals with implementation password manager with client-server architecture. Basis of thesis is proposal of graphical user interface, used keys, remote methods, server and its database, choise of used technology and programming language. The next part delas with implementation proposal of password manager.
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Effectivity of strategies for data backup
Šindler, Martin ; Ležák, Petr (referee) ; Burda, Karel (advisor)
This bachelor´s project is focused on efficiency of backups using mathematical models, which calculates overall capacity needed for backup and capacity required for complete recovery, it also compares availability of rotation schemes. Models are based on propability of data change in certain time interval specified as backup cycle. Models are implemented to the application, which can be used for choosing the best rotation scheme.
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Visualisation of asymetric cryptography
Kužela, Jan ; Rosenberg, Martin (referee) ; Ležák, Petr (advisor)
Bachelor thesis is considered in cryptographic protocols, especially asymetrical. The purpose of the thesis is to create an aplication for visualisation of mathematical operations in asymetrical cryptosystems. The emphasis is put on the asymetrical cryptosystems Diffie-Hellman, DSA and RSA. There is a summary of history of cryptography in the theoretical part as well as modern cryphographical systems used for protection of digital data. Practical part shows the design and creation of the application and implementation in the programming language Java and JavaFX. The output is the application, which visualizes protocols DH, DSA and RSA. Systems are visualized with the input data from the user or with randomly generated data. Application shows the calculations made by protocols step by step.
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Authentication of web service users
Plašil, Matouš ; Ležák, Petr (referee) ; Burda, Karel (advisor)
In this bachelor thesis are presented methods for Single Sign-On from perspective of client application. It takes a closer look at protocols OpenID and OAuth and explains the main differencies. Next part of the thesis is focused on registration of application and communication between server and client application. This is realized by OAuth protocol. In the practical part is described a created web application and used methods are explained.
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