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Influence of optical connectors and of other effects on optical link attenuation
Winkler, Aleš ; Křepelka, Václav (referee) ; Filka, Miloslav (advisor)
In this time the metalic wires meet not the requirements of high capacitance and rate wire and so the new, modern fiber wires are more and more being used. This bachelor`s thesis deals with three basic kinds of connections of fiber wires, optical connector, mechanical coupling a optical weld, and their effect on optical link attenuation realized by fiber optics. The optical link is possible realized number of kinds fiber optics. In this thesis are most often used multimod and a little multimod fiber optics. By mechanical coupling are explored their effects of attenuation on optical link a their detrition after disconnection and next connection back to the optical line. For optical weld is explored quality assignet optic welder. For optical connectors is explored their quality of cleanness through apparatus OTDR( Optical Time Domain Reflectometer) and geometrical properties through apparatus FIBO 250.
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"Triple Pley" - FTTH
Bobkovič, Peter ; Křepelka, Václav (referee) ; Filka, Miloslav (advisor)
This project is zaobíra possible implementation of the last mile connection to užívateli through FTTH, what is optics to the home. The whole work is divided into 2 parts, and to a general overview of FTTH and its own measurements. In general overview of the listed species gradually FTTH networks, problems associated with FTTH, zmapovaná situation in the world and Triple game (Pricelist, ponuka TV and under.). In the second part of the developed progressive measure, and the results of the three carried out measurements (PPM, OTDR, directly method) as well as the appearance of purity connector.
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Methods for searching and documenting optical cables
Havliš, Ondřej ; Křepelka, Václav (referee) ; Filka, Miloslav (advisor)
The purpose of this bachelor thesis is a description of searching for optical cables with metallic elements and EMS markers below the earth surface by suitable method and the possibility of recording and documentation of optical cables in a geographic information system ArcGIS. In the beginning there is a mention of an optical cable in particular of its the most important part, which is an optical fiber. Further there is the purpose what the optical fiber in the telecommunications world of techniques was developed for. Then there are the various advantages of the optical fiber described. This project also deals with the various methods of searching the optical cables using metallic elements. It is a called Galvanic and Inductive method, which are used to search for the optical cable by using the enclosed metallic lines, which, with the proper connection to a receiver, generates electromagnetic fields around. Another way to search the fiber optic cable is realized by the EMS markers. There are various types of passive electronic tags described. These electronic passive tags are manufactured in different color, which is used for marking the various branches of networks. There is the possibility of documentation of the optical cables by using ArcGIS geographic system from ERSI mentioned in the project. There is its structure and func-tion of individual subprograms in detail described. In the chapter GSM there is an analysis of operating principle of the system. At the end of this thesis the laboratory task is suggested. It describes the searching for fiber optic cable and the other metallic circuits by passive markers and iD markers.
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Simulation of optical route monitoring
Mlejnek, Zbyněk ; Křepelka, Václav (referee) ; Filka, Miloslav (advisor)
Monitoring optical line for a long term monitoring and evaluating both transfer quality and running reliability of optical line links' physical layer (optical cable routes) fiber optical transfer systems. Monitoring indicates any kind of security erosion of transmission medium incited by either "natural" climatic and mechanical environmental effects, indeliberated cable violation (building operation) or by intended intervention into transfer path.
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Optical cableless transmission
Němec, Filip ; Křepelka, Václav (referee) ; Filka, Miloslav (advisor)
This diploma thesis first handles the general issues concerning free space optics in the~atmosphere. The aim is to design and implementation of optical wireless equipment, which would serve in the laboratories of optical networks. Ronja was used as the basis for a~wireless link, which is already widespread in the world. Students will work with the device, which they may come into contact in the future. It consists several separate modules: transmitter, receiver and inteface. Each module have a separate chapter describing the~functional blocks and circuit realization. Ronja was adjusted for the needs of~laboratory tasks, where additional voltmeters measures received signal strength (RSSI) at~both ends of the link. Measuring device provides adjustment of power the transmitting LED via~computer, measures and sends RSSI values to a PC via~USB or RS232, turn off Ronja with computer. For targeting the pipes of Ronja was developed the mechanical design. In the last part of thesis the device was undergone a series of tests.
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Assembly of optical cables - effect on fiber parameters
Zelinková, Vlasta ; Křepelka, Václav (referee) ; Filka, Miloslav (advisor)
The aim of this paper is to describe the optical fiber manufacture, installation, utilization in practice and the parameters that affect its properties. The practical part was devoted to the creation of optical paths, the implementation of separate and subsequent measurement and evalution of the resulting values. Finally, the comparison is to measure fair values of laboratory measurements and tracks how much influence can have errors in the construction of optical lines to fiber parameters.
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Quality of Service in Converged Systems with Elements Controlled by Neural Network
Polívka, Michal ; Sýkora, Jiří (referee) ; Křepelka, Václav (referee) ; Škorpil, Vladislav (advisor)
The Quality of Service (QoS) is in converged systems an important parameter. The dissertation thesis deals with research of QoS implementation into a newly developed network element. There was designed and implemented new protocol, based on the IP. The dissertation thesis deals with proposal of a new network element – the switch controlled by a neural network. During the research have been measured switches cross a performance classes. On the base of the measurement was designed the new four-port switch with switch fabric build on crossbar switch with an external control. The switch was designed with maximum QoS support. The switch fabric is controlled by the feedforward backpropagation neural network. The designed switch was modeled in the MATLAB and Simulink. The simulations prove that developed solution is functional.
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Mitigation of Volumetric DDoS Attacks in SDN Environment
Hodes, Vojtěch ; Křepelka, Václav (referee) ; Škorpil, Vladislav (advisor)
The aim of this Master's thesis is to explore different attitudes and to design various monitoring and detection concepts of volumetric DDoS attacks in core networks. The thesis deals with data flow control protocols with an emphasis on a modern technology of Software Defined Networks. The last part of the thesis describes verification of the theory by setting up a laboratory environment for volumetric DDoS UDP Flood simulation, detection and automated mitigation.
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Connecting the TV studios
Flimel, Peter ; Křepelka, Václav (referee) ; Filka, Miloslav (advisor)
In this bachelor thesis work is done TV link study in 2020, for the purpose of mediation football matches between studies in Prague and Bratislava. This work deals with optical connections and technology matters to revel in the transmission of large amounts of data.
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Critical Parameters for Wireless Networks WiFi and WiMAX
Grenar, Milan ; Křepelka, Václav (referee) ; Baroňák, Ivan (referee) ; Filka, Miloslav (advisor)
My thesis will be aimed at problems of wireless networks WiFi and WiMAX. A modelling of network will be put into effect onto which the measurement will be implemented and the impacts of network load on the data transfer Quality of Service (QoS) will be examined with aiming at VoIP. On this network model a power failure will be simulated and the impacts of this failure after restoring the power supply will be monitored. The aim of this thesis is to check the rate of network throughput while preserving a providing service quality and to suggest an economica1ly acceptable solution of the problems relating to feeding tension outage of the access point (AP) for a practical usage in these networks.
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