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Distributed P2P Data Backup System
Mészáros, István ; Herout, Adam (referee) ; Szőke, Igor (advisor)
Tato diplomová práce představuje model a prototyp kooperativního distributivního systému zálohování dat založeném na P2P komunikační síti. Návrh systému umožňuje uživatelům přispět svým lokálním volným místem na disku do systému výměnou za spolehlivé úložiště jejich dat u jiných uživatelů. Představené řešení se snaží splnit požadavky uživatelů na ukládání dat, zároveň však také řeší, jak se vypořádat s mírou nepředvídatelnosti uživatelů ohledně poskytování volného místa. To je prováděno dvěma způsoby - využitím Reed - Solomon kódů a zároveň také tím, že poskytuje možnost nastavení parametrů dostupnosti. Jedním z těchto parametrů je časový rozvrh, který značí, kdy uživatel může nabídnout předvídatelný přínos do systému. Druhý parametr se týká spolehlivosti konkrétního uživatele v rámci jeho slíbeného časového úseku. Systém je schopen najít synchronizaci ukládaných dat na základě těchto parametrů. Práce se zaměřuje rovněž na řešení zabezpečení systému proti širšímu spektru možných útoků. Hlavním cílem je publikovat koncept a prototyp. Jelikož se jedná o relativně nové řešení, je důležitá také zpětná vazba od široké veřejnosti, která může produkt používat. Právě jejich komentáře a připomínky jsou podnětem pro další vývoj systému.
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FM Transmitter of APRS Telemetry in 144 MHz Band
Bohátka, Jan ; Šádek, Václav (referee) ; Urbanec, Tomáš (advisor)
APRS system is described are sent toin my essay, which is used for sending and receiving text messages. The text messages frequenc 144 MHz by using the modulation scheme AFSK. APRS communicate by using the protocol AX 25, which sends and receives the text messages in the area where are carried despatches and control bits as well. The whole area of high frequency part is in one integrated circuit. The control, coding and decoding of the area is the microcontroller’s job.
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Advanced speech coding methods using digital signal processor
Zajíček, Marek ; Sysel, Petr (referee) ; Smékal, Zdeněk (advisor)
This master thesis describes the practical usage of AMR-WB (Adaptive Multi Rate - Wide Band) codec and its implementation on a digital signal processor which is integrated in functional voice communication system Siemens HiPath 4000. The first part is focused on the complete codec description, especially on an encoder and decoder. The second part partly describes signal processors and then is followed by the practical part of the implementation which is solved from the preliminary activities up to the optimalization of the final functional solution.
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Methods Decoding Convolucional Code
Vlček, Peter ; Zezula, Radek (referee) ; Křivánek, Vítězslav (advisor)
Convolutional codes belongs to among linear tree codes. There are codes used for channel coding. At build - up project, then comparison separate algorithms were gateway into the account Viterbiho algorithm, Stack algorithm, Stack- bucket algorithm, Fano algorithm and Feedback decoding. Was built-up suggestion convolutional encoder and decoder, which at his activities make use of Viterbiho algorithm and Stack algorithm, what serves for contrast of both methods. It turned out, that the Viterbiho algorithm get past in the main for codes with smaller compulsory longitude, because has stand-by cost quantity calculated effect. At Stack algorithms is quantity calculated effect dependent on longitude received sequence, what may result in much smaller number calculated effect, however at very noisy channel is able to state, that the calculated effect will much more as with Viterbiho algorithm. Nothing less is Stack algorithm or his variation Stack- bucket algorithm used primarily on codes with bigger compulsory longitude. Feedback decoding is gainst for simple construction decoder acceptable alternative toward decoding most likely and to sequential decoding.
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Modern coding of speech signals using overcomplete models
Zapletal, Ondřej ; Průša, Zdeněk (referee) ; Rajmic, Pavel (advisor)
The theoretical contents of this thesis are studies of overcomplete models. Those are the models of signals, on which is set for their parametrization more variables, than it's necessary and consequently there's computed so-called sparse solution via iteration algorithms. A goal of this analysis is a selection just of the considerable (sparse) parameters. The theory is based on a linear algebra, vector spaces, bases and so-called frames. The task of the individual project of this thesis is a description and simulation of two speech coders: a classical coder based on linear predictive speech coding and a coder, that's making use of overcomplete stochastic ARMA processes models. A part of their realization is to simulate their decoders and a analyze their reconstruction quality. For their realization there is used MATLAB and an overcomplete models' library (toolbox frames).
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Tree Code Decoding Methods
Zamazal, Zdeněk ; Lambertová, Petra (referee) ; Němec, Karel (advisor)
This thesis deals with applying knowledge of data channel coding and concerns about possibilities of tree codes decoding. It describes several decoding methods and inquires their ins and outs. Basic knowledge of theory of information is necessary, it is presumed that reader is familiar with convolutional codes and coder definitions. Criterions for choosing decoding method are introduced and lightely described. A decoder is designed using method choosed by denoted criterions. Implementation of the decoder, using Matlab Simulink enviroment, has taken part in the thesis. Function of the decoder is verified in simulation.
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Anti-Error Coding Systems with Block Codes
Pacher, Jakub ; Zezula, Radek (referee) ; Němec, Karel (advisor)
This work deals with selection and proven suitable error-correcting code securing aggregating errors. First we give analysis anti-error coding system and requirements rapid/fire at them. The next text is focusing on survey and characteristics often used codes, mainly Fire, Hamming and two BCHs codes. After an explanation of Hamming code use, the text describes verification of proper function anti-error system in the MathCad enviroment.
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Navigation systems
Jirkovská, Šárka ; Stejskal, Vojtěch (referee) ; Pust, Radim (advisor)
This bachelor´s thesis is focused on the navigation systems GPS, Galileo and their development. The work describes the functions and parameters of mentioned navigation systems including individual modulation techniques, used frequencies and signal securing by encoding. Segments of navigation systems GPS and Galileo, which divide into control and space parts, are mentioned next. The principle of signals generation by GPS system satellites, where the navigation message is the basis of user´s data transfer, is introduced. The principle of generation of the navigation message is described as well as its structure and characteristics of used CA-code and P-code. Next part of the work presents the components of the Galileo navigation system satellites and conspectus of planned services of this system. The summary of used receivers’ characteristics and summary of selected producers of digital geographical data for navigation devices follow next. The last part mentions the simulation of signal generation of GPS satellite. The simulation includes encoding and decoding of navigation message. This simulation is created in Matlab version 7.4 environment.
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Effective usage of telecommunication education environment
Buchta, Marek ; Polívka, Michal (referee) ; Škorpil, Vladislav (advisor)
The topic of this bachelor´s thesis was effective usage of telecommunication‘s educational interface. The main aim of my thesis was to teach software and hardware versions of telecommunication‘s educational environment TIMS from Emona Instruments company. Also the goal of this paper was to design effective usage of educational environment in laboratories in the subject called Access and transport nets. There was a selection of three exercises suitable for these laboratories. These exercises were designed and implemented. Each of these exercises contains extensive theoretical introduction to solve problems, exercise assignment, block diagrams for visual understanding and for insight into measurement and detailed instructions to measurements. After all exercises have been completed exemplary protocols were created. The first exercise carried out was PCM coding and encoding in which students would be introduced with pulse code modulation, its advantages and disadvantages in way of acquiring high-quality broadcast. Second exercise was to focus on the introduction of quadrature amplitude modulation and phase shift keying. Target of the last exercise is to introduce students with binary data transmission via voiceband and factors affecting this transmission.
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