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Driver design for custom analog user module in Linux OS
Brejcha, Martin ; Sysel, Petr (referee) ; Molnár, Karol (advisor)
This master's thesis describes how to develop loable kernel module for operating system Linux. Module can be use like driver for concrete hardware device. In this case for telecommunication hardware. The second part of this thesis describes how to implement support for this hardware in Asterisk PBX. Support in Asterisk is realized by channel module. In that channel module are implemented functions for process incoming and dialed calls.
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Administration of development documetation over WWW II
Gregárek, Ondřej ; Sysel, Petr (referee) ; Balík, Miroslav (advisor)
Document server is a web application controllable by way of web browser. It is meant to serve for the management of development documentation. The application is divided to the four basic parts: Requirements, Products, Tests and Test Run. The section Requirements serves for inserting requirements for products. Product is produced on the basis of these needs and registered in part Products. Test setting is created in the part Tests according to requirements from the part Requirements. Particular products are then tested. The part Test Run registers records of these tests. These are parts of the application: management of users, connecting supplements to records, printing and exportation of data to different formats, saving history of records, filtration and sorting of entries, etc. All the data is saved in the database MySQL. The application is written in scripting language PHP. Data is presented by template system Smarty. The output is in language XHTML. Cascading style CSS is used to formatting. This work describes development of the application. First it is dealing with the proposal of the database, connection and structure of particular tables. The function of the programme is explained in detail at the same time, which is essential for the correct proposal of the database. The application is based on the database. The selected structure of files and relations of scripts to library functions are shown. The template system and the interface for access of the programme to the database are explained. The most attention is paid to the description of solving important functions of the application, i.e. listing of records, their pagination, filtration, sorting and operation with them: saving, browsing, copying, confirmation and work with history, category and problems by upkeep of consistent tree and export of data to various formats. It is always outlined the problem, the idea of solving and the description of appropriate scripts. Samples of source code are also included for better understanding of complicated algorithms.
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Isolated word recognition
Vodička, Radek ; Křupka, Aleš (referee) ; Sysel, Petr (advisor)
Main purpose of the thesis is to study the processes and methods of isolated words recognition. In the theoretical part a basic principals are explained. The practical part is about the program creating using these principles in practice. For isolated words recognition Hidden Markov Models (HMM) are used, for obtaining decision symptoms cepstral analysis is chosen.
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Protection of VoIP networks and their testing
Ulický, Ivan ; Sysel, Petr (referee) ; Krajsa, Ondřej (advisor)
Main goal of creating this diploma thesis is existence of increasingly amount of potential threats against IP voice networks (VoIP). The thesis is devoted to testing of various types of attacks and provides some possible solutions for this systems as well. The work points out to a various types of current attacks against either insecure or very little secure structures. The theoretical part is dedicated to analyse and description of wide spectrum of VoIP protocols including signaling protocols (SIP, IAX2), transport protocols (RTP, RTCP) and security protocols (SRTP, ZRTP, IPsec, SDES). Further attention is dedicated to the one of possible open source IP PBX solutions called Asterisk. There is shown a variety of possible attacks against this system due to its openness, because open systems always tend to be more susceptible for various attacks as they need an advanced administration and endless need for searching of new trends in area of security. The last block of the theoretical part is focused on common threats and types of attacks against VoIP networks. The practical part is about design and creation of web application called ,,VoIP Hacks using PHP” written in PHP scripting language and ist main task is to execute three basic attacks: eavesdropping, call drop and call flood. There is also a possibility of port scanning of selected network which is added as supplementary part of this application. The application can be comfortably managed from web browser user interface. All captured data can be displayed directly into the web browser. Tests of the application were performed on Google Chrome and Mozzila Firefox browsers. There is an accent placed on cooperation between the application and terminal linux programmes such as Tshark, BYE Teardown, INVITE flooder or Nmap, which all accept commands from web interface and interpret gained output values back to the web browser.
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Digital Audio Signal Feature Extraction and Modification in Dynamic Plane
Kramoliš, Ondřej ; Sysel, Petr (referee) ; Schimmel, Jiří (advisor)
This thesis deals with basic methods of root mean square and peak value measurement of a digital acoustic signal, algotithms to measure audio programme loudness and true-peak audio level according to recommendation ITU-R BS.1770-1 and digital systems for control of signal dynamic range. It shows achieved results of root mean square and peak value measurement and results of implementation of dynamic processor with general piecewise linear non-decreasing static curve and algorithms according to recommendation ITU-R BS.1770-1.
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Classification of transmission channels based on speech signal analysis
Báňa, Josef ; Sysel, Petr (referee) ; Atassi, Hicham (advisor)
The thesis examines the impact of VoIP transmission channel characteristics on speech parameters. It seeks ways of emulating properties of a selected VoIP transmission channel and creating a network emulation environment. Several scripts have been created in the Matlab development environment and used to modify and divide a continuous recording into parts identical to the original speeches, before passing through the transmission channel. Subsequently a database of speech recordings is created, as affected by selected characteristics - jitter, bandwidth, loss. Within these databases, symptoms are sought as the most evident characteristics of the transmission channel. Using correlation, symptoms are selected that are best suited for automated determination of the properties of transmission channel characteristics such as jitter, loss and bandwidth.
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Modeling of Linear Distortion of Audio Devices
Vrbík, Matouš ; Sysel, Petr (referee) ; Schimmel, Jiří (advisor)
Methods used for correction and modeling of frequency response of sound devices are discussed in this paper. Besides classic methods of digital filter design, more advanced and complex numerial methods are reviewed, Prony and Steiglitz-McBride in particular. This paper focuses on structure utilizing parallel sections of second-order IIR filters. Methods for calculating coefficients of this structure are presented and later implemented. For selected method, utilizing dual frequency warping, an interative algorithm for automatic calculation of parameters necessary to filter design is implemented - so called Particle Swarm Optimization. Six ways of evaluation filter design precision are presented and the results are compared. Functions realizing filter design are implemented in C++, MATLAB and Python. A VST module simulating the filter in real time is also provided.
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Multiplatform audio player
Malár, Ladislav ; Mach, Václav (referee) ; Sysel, Petr (advisor)
This master thesis deals with creating of the cross-platform audio player with the possibility of its use in the speech-language pathology clinic. The theoretical part is focused on the comparison of two multi-platform libraries, of which was one chosen for creating of the player. Subsequently on functionality SQLite database, which was also used as part of the final application. The basis of the practical part is the creation of the cross-platform audio player which is extended about database of patients and also extended about speech signal analysis with the help of VST plugin.
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