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Analysis of Wireless Signal Coverage
Šimek, Petr ; Šimek, Václav (referee) ; Očenášek, Pavel (advisor)
This master's thesis describes process of design and development of the system for calculating the coverage of wireless networks, it is implemented as a web portal and written in the Java programming language. The text of the thesis describes the work with the used platforms, a description of the ITU-R calculation method P.1812, which is used for calculation electric field strength and basic information about electromagnetic waves. The main function of the system is to calculate and display coverage of wireless networks and customer management information.
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Accuracy of non-contacting Temperature Measurement
Horák, Ladislav ; Janečka, Jan (referee) ; Vdoleček, František (advisor)
This master’s thesis is specialized on the influence of correct parameters of emissivity, which depends on the temperature, wavelength and ambient environment. The investigation the parameter was taken infrared non-contact thermometer MI3 from company Raytek. To improve the quality of measurement was designed and programmed measuring utility program. The program was developed in the LabView 8.5 programming environment. To obtain the true value of the measured temperature of the target was designed and constructed the touch thermometer with the resistance dependent sensor. The thermometer is connected to the communication box of infrared thermometer and contain the same program. Nowadays are the most advanced IR thermometer with fixed parameters emissivity, which is applicable just to the real body in the vicinity of the parameter emissivity 0,95. For those IR thermometers were designed correction function, which would have temperature measured at a fixed emissivity parameter 0,95 set close to the actual value of the object.
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A Brief Design of Optical Resonators
Hubík, Daniel ; Nešpor, Dušan (referee) ; Kadlec, Radim (advisor)
This bachelor thesis is focused on analysis of split-ring resonators in THz region. Simulations were made by finite elements method and by finite-difference time-domain method. At first we created a resonating structure that works in GHz region. Then we were observing a dependence of movement of resonant frequency on the size of resonator. In the final chapter we assigned frequency dependent values of permitivity to such structure. As the result we simulated working resonator at frequency 500THz. All simulations have been made in program HFSS ANSYS and Lumerical FDTD Solutions.
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Vectorial Kerr magnetometry
Flajšman, Lukáš ; Veis,, Martin (referee) ; Urbánek, Michal (advisor)
Increased complexity of novel magnetic materials in the last decade has placed high demands on the manufacturing process as well as on the characterization. One of the possibilities for characterization of magnetic samples is to exploit the magneto-optical effects. The presented work uses the magneto-optical Kerr effect as a major characterization technique to probe the magnetic properties of samples. We have developed a mathematical model describing the effect of the magnetization on the polarized light and present an apparatus capable of measuring the response given by the light-matter interaction. The experimental results show the performance of the apparatus on the various magnetic systems including meta-stable iron layers, Stoner-Wohlfarth particles and magnetic vortices. The scanning vectorial Kerr magnetometer allowed us to probe the vector of magnetization with diffraction limited resolution below 500 nm.
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Modeling of Signal Propagation in Wireless LTE and WiFi Networks in Indoor Deployment
Olbert, Jaroslav ; Mašek, Pavel (referee) ; Hošek, Jiří (advisor)
Masters thessis deals with the problematics of wireless signal propagation modeling inside buildings. The theoretical part of this thessis describes principles and methods of electromagnetic waves spreading in open areas and in indoor deployment. There are also described methods used for calculating the path of signal propagation ray-launching and ray-tracing. This part also includes description of an algorithm and equations used for simulating 5GHz WiFi signal propagation inside the Department of telecommunications corridors. Second part of this thessis includes a description of a NS-3 module mmWave, which was used for simulations of IEEE 802.11ad (WiGig) standard. There are also results of these simulations and their detailed description. At the end of this thessis comparison of these results with values gained by real environment measurements can be found.
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Whistler waves observed by the DEMETER spacecraft
Záhlava, Jan ; Němec, František (advisor) ; Macúšová, Eva (referee)
Although lightning-generated whistlers have been studied for nearly a century, there are still questions to be answered. It is clear that, at least in a certain frequency range, these waves significantly contribute to the overall wave intensity in the inner magnetosphere. They also influence distribution functions of energetic particles in the Van Allen radiation belts. Thanks to the on-board implemented neural network for automated whistler detection, we can relate electromagnetic wave and energetic particle flux measurements performed by the low-altitude DEMETER spacecraft with the number and dispersion of whistlers detected during a certain time interval. We distinguish the cases with high and low whistler occurrence and we use this information to determine the overall effect of lightning-generated whistlers. Powered by TCPDF (www.tcpdf.org)
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Dynamic elektromagnetic fields in the Kerr spacetime
Skoupý, Viktor ; Ledvinka, Tomáš (advisor) ; Kofroň, David (referee)
In this thesis we study a test electromagnetic field in the vicinity of Kerr black hole and with methods of extraction of its rotational energy. We are investigating a process in which a particle moves in an electromagnetic resonator around Kerr black hole. The energy of the particle is transferred to the electromagnetic field and the particle falls into the black hole with negative energy. We begin with the derivation of Maxwell's and Teukolsky equations and their numerical solutions. We derive a boundary condition for an electromagnetic field on a spherical mirror around the black hole, find the field that satisfies this condition, and describe the procedure for numerical calculation. Next, we calculate the trajectories of charged test particles in such a field and find particles that fall into the black hole with negative energy. We have found that it is possible for the particle to fall into the black hole with the energy of −124% of its rest mass, and the parameters of the electromagnetic field and trajectory of the particle need to be carefully selected.
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Analysis of Wireless Signal Coverage
Šimek, Petr ; Šimek, Václav (referee) ; Očenášek, Pavel (advisor)
This master's thesis describes process of design and development of the system for calculating the coverage of wireless networks, it is implemented as a web portal and written in the Java programming language. The text of the thesis describes the work with the used platforms, a description of the ITU-R calculation method P.1812, which is used for calculation electric field strength and basic information about electromagnetic waves. The main function of the system is to calculate and display coverage of wireless networks and customer management information.
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Whistler waves observed by the DEMETER spacecraft
Záhlava, Jan ; Němec, František (advisor) ; Macúšová, Eva (referee)
Although lightning-generated whistlers have been studied for nearly a century, there are still questions to be answered. It is clear that, at least in a certain frequency range, these waves significantly contribute to the overall wave intensity in the inner magnetosphere. They also influence distribution functions of energetic particles in the Van Allen radiation belts. Thanks to the on-board implemented neural network for automated whistler detection, we can relate electromagnetic wave and energetic particle flux measurements performed by the low-altitude DEMETER spacecraft with the number and dispersion of whistlers detected during a certain time interval. We distinguish the cases with high and low whistler occurrence and we use this information to determine the overall effect of lightning-generated whistlers. Powered by TCPDF (www.tcpdf.org)
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