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Testing the response of operating systems to different IPv6 flows
Ruiner, Michal ; Polák, Ladislav (referee) ; Jeřábek, Jan (advisor)
The aim of the thesis is to create an array of virtual machines and research their response to the IPv6 protocol. Another significant part is to utilize the provided tool for generating and sniffing IPv6 traffic and verify its correct functionality. For such purpose, the GNS3 open-source software is selected. A~reader is familiarized with the concepts of virtualization, GNS3 functionality and various methods of software testing together with the implemented practical models. The IPv6 protocol is introduced in detail as well as the packet format, address types and several IPv6 protocols useful for the thesis. The practical part is discussed in the Numerical results chapter. The topology is established and connectivity verified using IPv4. Configuration of static IPv6 addresses is performed on the devices as well as configuration of router to distribute particular prefixes. 5 testing scenarios are proposed that increase the input load to the tool in sense of higher number of addresses for the 3 different modes - passive, active and aggressive. 3 scripts were developed. Performance testing script measures utilization of computational resources. The other 2 scripts perform packet capturing and further analysis to compare the results of proposed scripts with provided tool. The comparison is done utilizing passive and aggressive modes. Active mode is used to observe the response of various operating systems to different IPv6 flows. Specifically, multiple Windows 10 builds, Linux distributions, Windows XP, 7, 11, macOS and Android.
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AI-based classification of RF signals
Turák, Samuel ; Ulovec, Karel (referee) ; Polák, Ladislav (advisor)
Táto práca sa zameriava na klasifikáciu rádiofrekvenčných (RF) signálov založenú na hlbokom učení. Pre tento účeľ, tri neuronové siete sú vybrané a prezentované: Konvolučná Neurónová Sieť (CNN), Sieť s Bránovými Rekurentnými Jednotkami (GRU), Konvolučná Hlboká Neurónová Sieť s Bránami (CGDNN). Všetky sú trénované a vyhodnotené na viacerých datasetoch, ovplyvnené rôznymi RF rušeniami, pre klasifikáciu rôznych bezdrátových štandardov. Signály v jednotlivých datasetoch boli vytvorené pomocou aplikácie Wireless Waveform Generator v programu MATLAB. Jeden verejne dostupný dataset na klasifikáciu modulácie je takisto testovaný na modeloch. Použité prístupy k predspracovaniu dát, tréningu modelov a vyhodnoteniu modelov sú implementované v programovacom prostredí Python s využitím knižníc ako Scikit-learn a Keras. \mbox{Získané výsledky} sú prehľadne prezentované a diskutované.
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Mapping and analyzing signal coverage in 4G/5G mobile networks
Baránek, Michal ; Jeřábek, Jan (referee) ; Polák, Ladislav (advisor)
Tato práce se zabývá s pokročilým měřením kapacity a spolehlivosti v mobilních sítích, zejména s rozšířeným přijetím technologií 4G a 5G. Vzhledem k tomu, že se tyto sítě stávají stále více nedílnou součástí každodenního života, existuje potřeba efektivních řešení pro hodnocení a optimalizaci jejich výkonu. Primárním cílem této práce je vyvinout cenově dostupná softwarová a hardwarová řešení schopná extrahovat základní klíčové ukazatele výkonu (KPI) z mobilních sítí 4G/5G. Navrhovaný systém si klade za cíl poskytnout uživatelům přístupný nástroj pro hodnocení výkonu sítě, pokrytí signálem v konkrétních oblastech a prediktivní modely pro budoucí kapacitu sítě. Tyto funkce jsou prezentovány prostřednictvím uživatelsky přívětivého grafického rozhraní (tzv. GUI), které umožňuje přímočará a cenově výhodná měření ve venkovním i vnitřním prostředí.
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Superpixel-based image segmentation to improve Intra-frame prediction
Soukeník, Ondřej ; Fliegel, Karel (referee) ; Polák, Ladislav (advisor)
This diploma thesis gives an overview of the technologies used for compression image data, video quality measurement methods and image segmentation methods. The thesis is divided into five chapters. The first chapter gives a brief overview of of the technologies and architectural elements used in image and video compression. The second chapter provides a brief overview of objective video and image quality metrics. The third chapter gives an overview of image segmentation methods and at the end of this chapter a new optimized implementation of SLIC is described. The fourth chapter aims to describe the modification of the rav1e encoder of the AV1 standard. The fifth chapter contains an experimental section where the encoder modification is verified and results are analyzed and presented in a summarized form.
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Coexistence of LoRa and Wi-Fi in the RF band 2.4 GHz
Kaučiarik, Filip ; Miloš, Jiří (referee) ; Polák, Ladislav (advisor)
Diplomová práca sa zaoberá štúdiom koexistencie, ktorá môže nastať medzi bezdrôtovými komunikačnými systémami LoRa a Wi-Fi v bezlicenčnom ISM pásme 2,4 GHz. V teoretickej časti práce sú stručne popísané fyzické vrstvy obidvoch systémov. Následne sú definované spoločné frekvenčné pásma a koexistenčné scenáre, ktoré môžu vzniknúť medzi uvažovanými systémami v spoločnom rádiofrekvenčnom (RF) pásme. V experimentálnej časti práce je prezentované laboratórne meracie pracovisko, ktoré bolo navrhnuté na meranie rôznych koexistenčných scenárov medzi technológiou LoRa a Wi-Fi. Funkčnosť navrhnutej koncepcie je overená experimentálnym meraním. Výsledky meraní sú detailne komentované a prezentované. Je navrhnutá laboratórna úloha a vzorový protokol pre vzdelávacie účely v Laboratóriu Mobilných a Bezdrôtových komunikácií.
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Measurement of diversity broadcasting in DVB-T2 standard
Koblischka, Vítězslav ; Kratochvíl, Tomáš (referee) ; Polák, Ladislav (advisor)
This bachelor thesis compares standards for digital and terrestrial television broadcasting of first-generation DVB-T and second-generation DVB-T2. It focuses particularly on the impact of interference in transmission media simulated by transmission channels for fixed, portable and mobile reception of terrestrial digital signal. Furthermore, the thesis compares SISO broadcast with the diverse MISO broadcast in DVB-T2 standard and evaluates the impact of the mode on error rate depending on the selected transmission channel and systems parameters that were used.
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Advanced algorithms for compression of video sequences with ultra high resolution
Soukeník, Ondřej ; Kratochvíl, Tomáš (referee) ; Polák, Ladislav (advisor)
This bachelor thesis provides an overview of advanced video codecs and explores their applicability for compression ov videosequences in ultra high resolution (UHD). The thesis is divided into two parts, theoretical and experimental. The theoretical part of the thesis gives an overview of advanced video codecs for video compression. Furthermore, objective metrics used for evaluation of the quality of a compressed video are briefly described. This part of the thesis also contains a detailed description of the created tool, employing a reference implementation of the selected video codecs, for easy compression of video sequences in UHD. This tool is used in the experimental part to compress different video sequences. The compression efficiency of each video codec is evaluated in terms of different objective metrics. Furthermore, the Bjntegaard Delta analysis is employed to obtain infromation about the compression efficiency of the used video codecs.
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Two-way stereo speaker system
Kočvara, Pavel ; Polák, Ladislav (referee) ; Kratochvíl, Tomáš (advisor)
The Bachelor thesis deals with design of a passive two-way stereo speaker system with performance 50 W RMS / 8 for normal domestic use. With respect to its sensitivity 90 dB/W/m mid-range speakers Beyma 5MP50/N and tweeter Beyma T2030 were used. The enclosure is a type of bass-reflex and it is made of MDF material with internal damping from polyurethane coat.
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Multimedia quality assessment for headset with virtual reality
Majnuš, Robert ; Polák, Ladislav (referee) ; Kufa, Jan (advisor)
This bachelor thesis deals with creating multimedia content for virtual reality and designing a subjective test to evaluate these sequences. In the introductory theoretical part there is information about virtual and augmented reality and several types of virtual reality glasses that are available on the market today. The second chapter focuses on methods of quality measurement and evaluation. These are subjective and objective evaluation metrics. The following describes the different types of codecs that are found in most of the sequences on the Internet portals. Then there is a chapter on creating content for virtual reality. Especially panoramic, 3D and 360 ° videos and photos. In the practical part of this semester work is described by me the procedure of editing sequences for individual codecs and design and use of subjective method including evaluation.
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