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Implementation of quality of service in a converged network
Zvolenský, Daniel ; Kovář, Petr (referee) ; Škorpil, Vladislav (advisor)
The point of this work is the creation of IP network with a proper topology, in Network Simulator version 2, where voice packet stream with recommended compresion by G.723 standard and real-time video by H.263 standard will be simulated. Theoretical part of this work consists of convergence of nets with an implementation of Quality of Services description. In practical part of this work is identification with bacis commands in program Network Simulator 2, which make possible simulation of network behaviour.
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Design of a laboratory exercise with frequency hops
Novák, David ; Číž, Radim (referee) ; Škorpil, Vladislav (advisor)
Novák, D. Brno: Department of Telecommunications, The Faculty of Electrical Engineering and Communication, Brno University of Technology, 2008, Design of a laboratory exercise with frequency hops. Bachelor’s thesis, supervisor: Doc. Ing. Vladislav Škorpil, CSc., 35 pages. Bachelor’s thesis consider about Design of a laboratory exercise with frequency hops. Theoretical part treat about technology of frequency hops. Below about types, properties, method about transfer and practical use of this technology. This event is maked from information acquired from practical part and from literature. Practical part serves such as extended manual to laboratory exercises into simulator system Emona TIMS. Exercises are concerned about measuring connection establishment between transmitter and receiver technology of frequency hops, speed and quality connection. Accent is set to detailed explanation objectives measuring. Bachelor’s thesis is complemented about measured out findings, these measurements.
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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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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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Optimisation of a Voice Transmission in Communication Networks
Novák, David ; Polívka, Michal (referee) ; Škorpil, Vladislav (advisor)
This master’s thesis deals abou the transmission of voice in communications networks. The theoretical part describes criteria for optimizing voice, such as quality of service, type of service, level of service, service type, and mean opinion score. Next I describe the Internet Protocol, comparing IPv4 and IPv6, VoIP, including security, protocols and parameters necessary for transmission. Other part is about neural networks. There are basically described the neural network, Hopfield neural network and Kohenen neural network. The research is based on a comparison of the network without ensuring the quality of service and with ensuring quality of service. Then, there are compared two types of switches. Classical switch-controlled sequentially, and switch controlled by neural networks. The overall simulation program is implemented in Opnet Modeler. The conclusion deals with the creation of laboratory tasks in this program to compare the different systems of ensuring quality of service.
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Network Element with Advanced Control
Zedníček, Petr ; Kacálek, Jan (referee) ; Škorpil, Vladislav (advisor)
The diploma thesis deal with finding and testing neural networks, whose characteristics and parameters suitable for the active management of network element. Solves optimization task priority switching of data units from input to output. Work is focused largely on the use of Hopfield and Kohonen networks and their optimization. Result of this work are two models. The first theory is solved in Matlab, where each comparing the theoretical results of neural networks. The second model is a realistic model of the active element designed in Simulink
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Optimization of Active Network Element Control
Přecechtěl, Roman ; Kacálek, Jan (referee) ; Škorpil, Vladislav (advisor)
The thesis deals with the use of neuronal networks for the control of telecommunication network elements. The aim of the thesis is to create a simulation model of network element with switching array with memory, in which the optimization kontrol switching array is solved by means of the neural network. All source code is created in integrated environment MATLAB. To training are used feed-forward backpropagation network. Miss achieve satisfactory result mistakes. Work apposite decision procedure given to problem and it is possible on ni tie up in an effort to find optimum solving.
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Education application for Internet environment
Kratochvíl, Peter ; Škorpil, Vladislav (referee) ; Zeman, Václav (advisor)
This Master‘s thesis is dealing with the usage possibility of education application for internet environment in learning process. Nowadays, this kind of applications is called the E-learning system. Theoretical part is focused on basic principles, describes the reasons why are these systems so popular and used world wide. Negatives and positives of both, the e-learning system as well as the classic form of studying are described. Content of this part also shows the usual usage cases. Practical part deals with construction of the particular system, based on requested features. The main system was divided into the two main logical parts. Their functionality is well described. In this part also all used programming languages as well as tools and server operation systems are mentioned. Practical part is also used to show information about database system and description of the particular database which was created. In the conclusion can reader find the summary of all practical and theoretical results achieved during the work on the project.
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Security Protection efficiency improvement for Wireless Networks
Marušek, Michal ; Burda, Karel (referee) ; Škorpil, Vladislav (advisor)
Nowadays every wireless radio-communication services encompass huge type of technology used for transfer video, voice or data. Wireless communication is the most expanded branch and many companies are using this technology because of low cost and simply management. The biggest advantage is easy connection to shared wireless medium and allows users of network to move around whole covered area. The most expanded types of wireless networks are called Wireless LAN (WLAN). With rising number of WLANs is rising chance to attack shared wireless medium by hacker and many sensitive information can be stolen or modified. To avoid this chance was created the first security protocol used in WLAN called WEP. Its goal was protect data transmitted trough WLAN as strong as were protected in wired networks. Unfortunately WEP was hiding a big weakness which can be used in a crack of WLAN in a minute with the aid of special software. Example of this kid of software can be Airsnort constructed to monitor shared medium and captured every packet transferred trough this medium. Based on statistical method Airsnort can obtain hidden password in a few minutes. The second type of this software can be Aircrack-ng, which can crack hidden password without any user connected to WLAN. Aircrack-ng uses active techniques to generate network load and can obtain password more effectively and faster. The result of both cases was successful and protection of WLAN was completely cracked. Later was created new security protocol called WPA, which had to fix the cryptography weakness of previous WEP. WPA was only temporary security protocol, during standard 802.11 was developing which had to offer highest security and integrity protection of transferred data trough WLAN. For this reasons was created new version of WPA called WPA2 which satisfy requirements of standard 802.11i. Both protocols WPA/WPA2 contain weakness, which can crash security of WLAN. This crack is based on authentication PSK. Attacker during authentication is using information from four-way handshake between user of WLAN and access point. Based on this information attacker can crack password with the aid of password list attack which took approximately 30 minutes. Based on previous result is important to chose strong password contains alphanumeric string or special strings with satisfy length.
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Implementation of Quality of Service into Wireless Networks
Kaman, Štěpán ; Růčka, Lukáš (referee) ; Škorpil, Vladislav (advisor)
Wireless networks are currently the frequent access connection to the local network or the Internet. Until 2005 there was no support in the 802.11 standard priority data and the use of multimedia services in these networks is problematic. Thesis deals with the standard IEEE 802.11 standard and quality of service support including IEEE 802.11e. They discussed methods of access to transmission medium, differences in the MAC sublayer, the reader issues in the transmission of priority data and the requirements for these data. In Opnet Modeler was created wireless network with access points and stations on which they are carried out simulations at different strain of transmitted data. It studied the difference in the use of DCF and EDCF method, used in the network with QoS support. In particular, it examined the behavior of priority voice and video data in both networks. The focus is on key parameters such as throughput, dropping data, packet loss, delay, jitter and the size of broadcasting front. The measured data are analyzed, and differences in the network without the support and promoting the quality of services are compared and evaluated. Part of this work is the role of laboratory in the Opnet Modeler.
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