National Repository of Grey Literature 34 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Multimedia transmissions in IP networks
Kejík, Tomáš ; Slavíček, Karel (referee) ; Grenar, David (advisor)
The topic of the master’s thesis is "Multimedia transmissions in IP networks". The goal of the thesis was to perform a theoretical analysis of multimedia transmissions in IP networks and to create a basic test set for generating and measuring network traffic. The theoretical part is devoted to the basic types of IP video transmission and the methods of transmitting in IP networks. Furthermore, protocols for controlling or distributing multimedia content are described. The practical part deals with creating the script written in the Bash language. The test script contains a set of functions that are created by different network tools. A Bash installation script has been created to install all the necessary tools automatically and conveniently. In order to generate multimedia and data traffic, the vlc and nc commands were used. The multimedia data editing was handled by the ffmpeg tool and to graphically display the measured data the smag and youplot tools were used. Additionally, the efficiency of the selected compression formats depending on the playback speed of the Raspberry Pi 4B single-board computer was also compared.
Utilization of open source tools for access network monitoring
Gmitter, Jakub ; Sládok, Ondřej (referee) ; Grenar, David (advisor)
The bachelor thesis deals with the issue of access network monitoring, which is necessary to ensure the stability of access networks. It contains a comparison of suitable monitoring tools for their selection. The work is focused on creating scripts in the Bash language, which analyze data on the access network and implement outputs from selected monitoring tools. In this work were analyzed the transmitted packets and the achieved transmission speeds during monitoring. The final output of this work are databases created in MySQL, which contains data about the analyzed parameters and visualization of data analysis using the Grafana program. Graphs of the transmission speeds of monitoring and basic transmission statistics were created on panels during visualization.
Multi-channel polarization optical fiber sensors in wave multiplex technique
Švehlík, Martin ; Grenar, David (referee) ; Filka, Miloslav (advisor)
The diploma thesis deals with the optical fiber sensor system assembly and its possibilities using 100 GHz wavelength multiplexing (DWDM), when using standard single-mode communication fibers. In the introduction, the necessary theoretical knowledge is discussed. The aim of the work is to design a temperature field violation sensor with remote excitation and detection. The practical part of the thesis contains the design and assembly of the measuring workplace. Also, the results of each measurement are presented, and at the end, they are compared and assessed.
Optical fiber polarization sensor optimalization for detection of fast and small temperature changes in military objects
Sergeev, Roman ; Grenar, David (referee) ; Filka, Miloslav (advisor)
This bachelor thesis deals with the design of an optical fiber thermal (temperature) sensor suitable for application in a military building. The thermal sensor detects even slight temperature changes based on the change in the polarization state of the light. The thesis describes the basic theory, which serves as a source for understanding the principle of operation of the fiber optic sensor. In the practical part, the basic quantities describing the polarization state of light were measured. The measured values were plotted in graphs to illustrate the dependence. This thesis aims to measure the designed variants of the sensor connection and select the most suitable for temperature measurement.
Measurement of qualitative parameters in the access network
Kejík, Tomáš ; Slavíček, Karel (referee) ; Grenar, David (advisor)
The theme of this bachelor’s thesis is „Measuring of qualitative parameters in an access network.“ The aim of this paper is a characterization of multimedia broadcasts in access networks and the creation of a functional network generator. The theoretical part of the paper is dedicated to analyzing key broadcasting parameters, which affect the resulting quality of network broadcast. Furthermore, used network protocols that are given for network and multimedia broadcast are analyzed. Simulation is done by using of GNS3 software. After that, transferred data were measured. Side effects affecting the functionality of the resulting transmission were subsequently analyzed. Another part of the paper is the practical part, which is focused on creation of a network generator by using the Bash language and making a script to facilitate turning on the generator for different counts of clients. At the end of the paper, the broadcast parameters were evaluated.
Tolerance zone measurement on polarization multiplex
Soktueva, Galsana ; Grenar, David (referee) ; Filka, Miloslav (advisor)
The thesis deals with the measurement of tolerance zone of a polarization multiplex. The theoretical part deals with polarization of light, mathematical description using Stokes and Jones vectors and the representation of the instantaneous state of polarized light using a Poincaré sphere. It also deals with optical transmission and multiplexing. The final part of the thesis describes the design of the measuring workplace and its implementation.
Design of optical fiber temperature sensor for detection of defense perimeter
Zámečník, Ondřej ; Grenar, David (referee) ; Filka, Miloslav (advisor)
This diploma thesis deals with the issue of measuring the ambient temperature using a~single-mode optical fiber used as a temperature sensor. The thesis describes the basic knowledge about polarized light, its propagation in optical fiber and describes special fibers that preserve polarization. It also deals with the representation of polarization states on a Poincaré sphere and the use of Stokes and Jones vectors. In the practical part, several selected methods of optical signal supply to the temperature sensor are measured. Subsequently, the suitability of the given methods is evaluated from the measured results and the courses are compared with the records measured from real routes. This thesis aims to select a suitable connection of a temperature sensor for a long route of optical fiber and verify its functionality.
Measurement of polarized light properties on the dense wavelength division multiplexing in optical-fiber sensor systems
Bučko, Kristián ; Grenar, David (referee) ; Filka, Miloslav (advisor)
The polarization of light is one of the most remarkable phenomena in nature and has led to many discoveries in the optical-telecommunications sphere. The master's thesis describes the basic knowledge about polarized light, which includes the types of light polarization, the issue of Poincaré sphere, polarizing ellipse, etc. Emphasis is also placed on the measurement of optical power, where the analysis of various types of photodetectors and also polarimeters was performed. In the practical part of this work, the design of the workplace itself is described in the diagrams. Also, all devices in the workplace are analyzed and subsequently demonstrated measurement in several scenarios. The final chapter is a discussion with the measured results and graphical dependencies, comparison and analysis of results.
Long optical fibre routes influence on the polarizing state of light and uses it for powering polarization sensors
Panascí, Marco ; Grenar, David (referee) ; Filka, Miloslav (advisor)
This diploma thesis deals with the influence of long fiber optic paths on the polarization state of light and their use for powering polarization sensors. The aim of the diploma thesis was to design the arrangement of optical fiber components so that the polarization properties of light at the end of the path are further usable for sensory purposes. Four partial measurements with a long path (in a laboratory setting, laying in the ground, on a curtain, under the influence of external influence) and one measurement without a path under the influence of external influence were designed. The overall measurement results demonstrate that for the functional power supply of long-distance sensor systems, an existing single-mode fiber can be used (laid by laying in the ground), into which a light source for a given sensor system would be multiplexed. In the discussion, all types of measurements are analyzed and compared with each other. Finally, the overall result is summarized and applications are described in which such a sensor system could be used.
Network Performance Optimization
Grenar, David
It is necessary to monitor the usage of network resources within the network, and provide the solution in order to avoid network congestion problems. Based on it, a real-time network traffic analysis followed and optimization of the performance benefits. Paper will implement solution of congestion problems with packets, which are processed in RouterOS. This method will combine with mangle, firewall rules, so that we can manage the internet connection to our network ideally, and prioritize the connection packet that we want to get priority in size as we need.

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5 Grénar, David
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