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802.11 standard security techniques and their features
Endrle, Pavel ; Pust, Radim (referee) ; Pfeifer, Václav (advisor)
This master´s thesis is about 802.11 standard security techniques and their features. Particular types of this standard and its features are shown in the introduction. Wireless network security cypher alghoritm types, their features, weaknesses and principles of functions are closely described in next few chapters. Realized attacks on these security alghoritms with their principles are described and shown in the practical part of thesis. One chapter is about effectivity, accessibility and practicability valorization of these attacks in practice.
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Decoder for key word detection system
Krotký, Jan ; Míča, Ivan (referee) ; Pfeifer, Václav (advisor)
The essay presents the basic characteristics of human speech recognition, describes systems for the detection of key words and further deals with the proposal of each decoder blocks divided into three chapters. The first one describes the operations that are performed before the signal distribution of the framework and the segmentation. The second chapter describes the calculation of short-term energy, the number of zero passes and self-correlative, prediction and Mel-frequency cepstral coefficients. The third chapter, which describes the design of the block decoder, describes the method of dynamic time destruction and the method based on hidden Markov model. The final part of the essay describes decoders working with a speech and a proposal for a simple decoder working with isolated words, which was based issued and tested based on the preceding chapters.
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Analysis of noise characteristics of radioactive emission detectors
Šik, Ondřej ; Pfeifer, Václav (referee) ; Andreev, Alexey (advisor)
The main goal of this Master’s thesis is to describe relationship between low frequency noise spectral characteristics of Cadmium-Telluride radiation detectors depending on applied voltage and detectors reaction to illumination of various wavelengths. Also, the reaction and influence of higher operating temperatures were investigated. The noise measurements shown that the dominant noise type at low frequencies is the 1/f noise. Several samples with different resistivity were tested. By comparing results, we are able to estimate the quality of detectors and their sensibility to illumination and higher operating temperatures. We have found that all the studied CdTe detectors are sensitive to one particular wavelength of 548nm. Resulting data were processed by EasyPlot program that provided graphical representation of spectral noise characteristics. All measured characteristics of tested samples are compared and it’s estimated the similarity between the samples.
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Modern conception of virtual class system
Outěřický, Pavel ; Průša, Zdeněk (referee) ; Pfeifer, Václav (advisor)
This thesis is focused on problems of an interactive distant education with usage of virtual classroom as a software communication tool. The short analysis of types of human communication and education is followed by a description of virtual classroom systems in a very basic point of view like what the virtual classroom is and what its usage is and what advantages these systems have. Furthermore, potentialities and supported tools and functions of today’s commercial and also non-commercial products are described including illustrative examples and focus to potential types of network communication implementation. Next section of the thesis presents possibilities of virtual classroom software development as completely web-based application or as desktop application where usage of different programming languages is considered. After that, videoconference as a often used tool in virtual classroom is described and its demands on the ways and types of realization and implementation are stated. The second part of this thesis creates about three quarters of whole document and is dedicated to description of my own realization of virtual classroom system as a built-in-java desktop application communicating across a built-in-java server desktop application. The first section of this part introduces a basic design and concept of the system including its implemented tools for the distant education. The following chapters describe in details each implemented tool and function from the potential user point of view and also developer point of view.
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Application of system catalogue for database management
Nečas, Jaroslav ; Pfeifer, Václav (referee) ; Kacálek, Jan (advisor)
The purpose of this project is to create a design and subsequently the web application for a database management which uses the system catalogue of the Microsoft SQL database system. The introduction deals with the principle of the relational databases and includes the list of the most widespread database systems. The next chapter of the theoretical part describes the syntax of the SQL query language, and the next chapter deals with the properties of the system catalogue which were utilized. Finally, the last of the theoretical chapters is centred on the .NET platform and its technologies – particularly the ASP.NET and the ADO.NET technologies. The former is used for creating dynamical web pages, and the latter is an object library used for the data access. The practical part of this work comprises the web application scheme on which is the final web application based. The most emphasized issues in this part are the security and the supposed program design of the web application. The final part of the work contains a description of the finished web application, especially the configuration and the functions which the application provides to a user. And finally, the whole project is briefly evaluated in the conclusion.
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JAVA- and LABVIEW-based virtual laboratory
Bugla, Marek ; Malý, Jan (referee) ; Pfeifer, Václav (advisor)
Dielektrické materiály jsou použivány v elektronice i v elektrotechnice. Jako jejich základní vlastnost může považovat změnu jejich charakteristik během jejich životnosti. Změny jsou způsobeny namáhaním materiálu vyvolané elektrickými či teplotími vlivy. Možnost jak určit průběh jejich charakteristik v závislosti na čase je měření proudu během aplikování elektrického napětí na materiál. Tyto experimenty vědci z LEMD provaděli ručně, tento postup ale není přílíš učinný pro vysokofrekvenční signály nebo pro experimenty s dlouhou periodou. Hlavním cílem této práce bylo vytvořit aplikaci v LabVIEW k ovládaní měřícího přístroje Keithley (generátor napětí) a k automatickému získavání měřených hodnot v pikoampérech. Tato aplikace nabízí uživateli různé funkce: - Zadání vystupního napětí. - Vyběr typu průběhu. - Definování délky periody. - Ovládaní přístroje. - Měření proudu, ukládaní dat do souboru vhodného pro jiné aplikace (textový soubor). - Analýzu naměřených dat.
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Modern e-learning system on the JAVA platform
Hák, Tomáš ; Polívka, Michal (referee) ; Pfeifer, Václav (advisor)
This dissertation is studying e-learning – electronic form of education. At once it is analysing in details the advantages and disadvantages of this new form of education approach and is describing possibilities of some chosen e-learning systems and their basic structures. In the second part of this dissertation are said basic principles and possibilities of programming language Java in which language is designed it's own concept of system, that should make possible for users to manage and control the e-learning. In this part is described progress of communication between server and client, method of sending off the SQL (query) and receiving result too. In last part is viewed resulting application as a whole, is explained basic controlling, possibilities of administration and methods of entering data. Application itself is tested on local testing server.
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Optimization of network position prediction
Pospíšil, Petr ; Pfeifer, Václav (referee) ; Burget, Radim (advisor)
This work is about position prediction in network, it is focused to find Landmark closest to the Host in the network (with lowest distance vector). The algorithm is based on GNP system. In terms of GNP system simulation was selected method for mathematical part of position prediction. The method was Simplex Downhill. The designed algorithm was implemented in Java. In the first step chose Host continent by meassuring the distance vector. In next step is selected nearest part in the continent. In conclusion estimate Host its position and then closest Landmark. Results from this work is important for designing TTP protocol. The verdict is that the GNP can be used for TTP, but Landmarks must be located in uniform density.
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Security and architecture of IPTV content manager
Šimko, Daniel ; Pfeifer, Václav (referee) ; Burget, Radim (advisor)
The aim of my thesis is to analyze, propose and implement the application of IPTV Manager.The analysis probes the requirements for the application and its results are displayed in UML diagrams. The proposal is mainly focused on application's architecture and on the choice of modern technologies that faciliate its realisation.The security of the application is highly emphasized in the proposal and in the implementation itself.
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