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Modulations in PLC systems
Procházka, Vít ; Kouřil, Jiří (referee) ; Krajsa, Ondřej (advisor)
The bachelor thesis describes principles and methods of Powerline Communications, practical usage possibilities both in industrial applications but mainly in broadband systems that may represent promising competition to conventional broadband access, e. g. xDSL connections without the need of new wiring, WIFI etc. The thesis also focuses on problems that can occur in the communication channel from the view of electromagnetic compatibility and assorted interferences. The 50 Hz frequency electric network (60 Hz in the USA) was not designed for data signal transmission, problems may arise mainly at higher frequencies and broadband communication. It is necessary to implement methods which enable transfer of information signal through a communication channel with minimalization of problems such as interference, cable attenuation, electromagnetic compatibility, bit error rate (BER), etc. Furthermore, currently used modulation principles and their characteristics are described, such as spread spectrum modulation DSSS, FHSS, traditional OFDM, alternative modulations FMT and DWMT with filter banks. The last chapter of the bachelor thesis features models of particular modulations created in the Matlab-Simulink program and the conclusion presents advantages and disadvantages of their implementation in PLC systems.
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Wireless PC controll
Macháček, Jiří ; Burian, František (referee) ; Macho, Tomáš (advisor)
This work deals with design of PC remote control, which is able to control computer with operating system Windows and Linux using Wifi connection. There was also created necessary support software for both operating systems. Communication was secured by ciphering algorithm.
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Analysis of security and authentication of wireless networks
Kulíř, Tomáš ; Jeřábek, Jan (referee) ; Szőcs, Juraj (advisor)
This master's thesis deals with wireless networks, mainly about the WiFi. It deals with summary of individual security mechanism both theoretically and using them in real hardware. Mainly it is interested in the security of the individual mechanisms and their weaknesses, which cause rupture of security. At each chapter the ideas and methods, that the attackers are trying for infiltration of wireless networks and decrypt encryption WEP, WPA or WPA2, are outlined. The principle of the authentication of the WiFi by the authentication server and its options, which is connected with directory service LDAP, is also explained in this thesis. The penultimate chapter deals with the summary of security mechanisms and references that should be adhered by design of the WiFi for the provision of the high security. The ending of the master's thesis is devoted to social engineering and its most famous representatives.
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Wireless network attacks
Brusnický, Pavel ; Martinásek, Zdeněk (referee) ; Stančík, Peter (advisor)
Objective of this thesis is to point out to almost everywhere present flaw in realization of second level network security access to WiFi networks with using traffic tunneling over DNS protocol. Realization has been accomplished by existing utilities OzymanDNS, DNS2TCP, NSTX, Iodine, Heyoka. Measurements were done on realistic traffic on the network. The effort was to show outline of these implementations. Transfer speeds in some implementations can be marked as applicable thanks to high speeds, which are on the same level as broadband internet. Functionality was tested on WiFi network, where was also compromised PPTP VPN tunnel, its function was to provide security of the communication on wireless network due to absence of first level security mechanisms such as WPA, WPA 2 and so on, with the help of Asleap, which comes out of Cisco LEAP attack. At the end of the work are suggested possible countermeasures for securing network by the topology change of the network infrastructure or by implementing IDS.
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Multiparameter circulating pump driver
Pazour, Zbyněk ; Frýza, Tomáš (referee) ; Kratochvíl, Tomáš (advisor)
This master’s thesis deals with design of the regulation of a circulating pump in a solar system for heating of supply water and design of the regulator for this system. It describes a fundamental principle and layout of a regulated circuit of a heating system. Description of regulation, basic terms, properties and differences between different types of regulation are described in first part of the master’s project. Especially continuous (PID regulator) and discrete (PSD regulator) regulation are presented. Second part of the master’s project is focused on a conceptual design of the circulating pump regulator. The connection system of each part, selection conditions of components and connection scheme of regulator are described. The third section deals with design of controlling algorithm of the regulator. There is a detailed description of libraries and functions in each chapter which were used in programming of PSD regulator algorithm. The regulated system of a solar collector is described at the end of the work. This system is being developed for real testing and setting of regulator.
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Efficiency of Wireless Networks from Services View
Buchta, Marek ; Vymazal, Michal (referee) ; Škorpil, Vladislav (advisor)
Subject of this thesis was the issue of effectiveness of wireless networks from the perspective of services. Become acquainted with WiFi network standard IEEE 802.11 with protocols and principles of WiFi networks and services. It should be focused on the quality of service QoS. In teoretical part of this thesis are described problems considering wireless networks, layer model and types of nets used in WiFi. Standard IEEE 802.11 is analysed in details including supplements and used packets. Special attention is paid to the quality of service QoS. Next are discussed the principles and application services as VoIP, videoconferencing, video streaming and others in WiFi network. On the basis of obtained knowledge is designed extensive WiFi network with assured supply of services. For modelling and simulation of wireless network is used software development environment Opnet Modeler. Model of wireless network is used to optimize and analyse this wireless communication network. In thesis are also simulated properties of data which are sensitive to delay. In last part of thesis is created a laboratory work, which contains a submission of task, detailed theory, wiring diagram, instructions for elaboration, guidelines for simulation and example of elaboration of task. Work is about comparison of network with used 802.11b and 802.11e standard, and support of quality of service QoS.
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Home Security System
Herold, Radek ; Fiedler, Petr (referee) ; Bradáč, Zdeněk (advisor)
In the opening part of this thesis, the reader is briefly introduced into safety technique devices. There are basic types of security sensors discussed together with the most common methods of their connection with the security central. Further text focuses on elaborating the main topic of this thesis - the design of home security central equipped with a WiFi interface.
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Wireless Network Security
Sedlák, Břetislav ; Krajsa, Ondřej (referee) ; Lambertová, Petra (advisor)
Master thesis focuses on wireless network security. The thesis is divided in two parts. First part describes today’s used standards and their components, topology and security methods as stealth SSID, MAC addresses filtration, WEP, WPA and WPA2. The last three methods are described in detail. In second part there are realized attacks on above described methods of security. There are described attacks on WEP as KoreK chopchop attack, fragment attack, attack FMS, KoreK and attack PTW. Then is described the dictionary attack on passphrase by WPA/WPA2 with PreShared Key authentication obtaining, precomputed hash tables for faster passphrase finding and for using more core procesors during dictionary browsing. The last attack describes obtaining of keystream used for encrypting of frames by WPATKIP and then sending custom data to client. It is described how to carry out each attack and how to protect against them.
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Analysis of the wireless network security
Bencel, Jozef ; Koutný, Martin (referee) ; Jeřábek, Jan (advisor)
This master's thesis deals with security of wireless network standard 802.11. There are described security mechanisms as hide SSID, MAC address filtering, WEP, WPA, WPA2 protocols. There are described also the most often kinds of attacks (Denial of Service, disclosure WEP key, Man-in-the-Middle). The work contains investigation of used security mechanisms in wireless networks in parts of Brno. There were used NetStumbler and inSSIDer applications for this measurement. The last part of work contains measurement of security mechanisms (WEP, WPA, WPA2) effect to transfer rate from the point of view of the end user. The measurement was realized with Iperf application.
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Infrastructure of public keys
Bědajánek, Ondřej ; Malý, Jan (referee) ; Pust, Radim (advisor)
The subject of my thesis dscribes function and principles of the public key infrastructure as well as certificate authority. Under the operation system Linux was created self signed certificate authority. Web interface was devoloped in PHP for the purpose of the generation, distribution and rejection certificates. Configuration files for OpenVPN are included in the thesis and wireless security is achived by OpenVPN.
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