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Classification of transmission channels based on speech signal analysis
Báňa, Josef ; Sysel, Petr (referee) ; Atassi, Hicham (advisor)
The thesis examines the impact of VoIP transmission channel characteristics on speech parameters. It seeks ways of emulating properties of a selected VoIP transmission channel and creating a network emulation environment. Several scripts have been created in the Matlab development environment and used to modify and divide a continuous recording into parts identical to the original speeches, before passing through the transmission channel. Subsequently a database of speech recordings is created, as affected by selected characteristics - jitter, bandwidth, loss. Within these databases, symptoms are sought as the most evident characteristics of the transmission channel. Using correlation, symptoms are selected that are best suited for automated determination of the properties of transmission channel characteristics such as jitter, loss and bandwidth.
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Laboratory of Quality of Service
Eltahir Ahmadon, Ahmed ; Kolka, Zdeněk (referee) ; Polívka, Michal (advisor)
Abstrakt Bakalářská práce se zabývá problematiku IP telefonie, emulace sítě a kvalitou službou (QoS). Kapitol 2 pojednává o model TCP/IP a OSI, síťových protokolech (IP, TCP, UDP) a o protokolu SIP. Kapitole 3 se zabývá problematikou QoS, definicí QoS, QoS ve službách s reálným časem, parametry a způsoby změření kvality hlasu – subjektivními a objektivními testy. Na základě získaných poznatků byla navržena laboratoř kvality služby. Laboratoř je zaměřena na testování kodeků z hlediska kvality přenášeného zvuku, s ohledem na šířku pásma a ztrátovost paketů. Laboratoř kvality služby byla navržena tak, aby byly splněny požadavky na subjektivní testy uvedené v kapitole 3. 4. Návrh laboratoře Schéma navržené laboratoř je zachyceno na obr. 4.1. Návrh je složen ze čtyř hlavních částí – Dvou softwarových IP telefonů (XLite), síťového emulátoru (WANem Wide Area Network emulator), a SIP ústředny (3CX Phone System pro Windows od 3CX Ltd). Sestavování spojení prbíhá podle stejného schématu viz obr. 4.1. Oba koncové uzly jsou připojeny přes emulátor WANem. Počítač, na kterém je emulátor instalován má dvě síťová rozhraní. PC1, resp. PC2 s WANem tvoří lokální síť 1 (LAN1), resp. lokální síť 2 (LAN2). Pakety prochází z jednoho uzlu do druhého přes WANem. WANem emuluje chování skutečné WAN sítě, umožňuje provádět v laboratorním prostředí testy na síti s přesně definovanými parametry. Návrh celé laboratoře je virtualizován. Je využita platform VirtualBox od Oracle. Podrobně je návrh popsán v kapitolách 4.1 a 4.2. QoS měření Během měření byly dva parametry sítě proměnné, resp. přesně určené nastavením WANemu – šířka pásma a ztrátovost. Protože testování probíhalo v místnosti, ve které se nachází elektronická zařízení a jiné zdroje ruchů, byla metoda ACR daná doporučením ITU-T P.800 upravena viz kapitola 4.3.1 Testovanému subjektu byly testovací nahrávky přehrávány do sluchátek. Dle ITU-T Rec. P.800 doporučuje několik metod hodnocení kvality služby – MOSLQ, MOSLE, MOSLP, ACR a CCR. K praktickému ověření funkčnosti navržené laboratoře byla vybrána modifikována verze ACR (M-ACR). Použité náhravky obsahují tři věty, mezi něž jsou vloženy mezery (volný interval – bez zvuku). Výsledky subjektivních testů jsou shrnuty v tab. 4-1 až tab. 4-10. MOS byl vypočítán pomocí rovnice (3. 1), jehož výsledky shrnuty v tab. 4. 11. Závěr Navrhovaná laboratoř byla úspěšně otestována, návrh splnil očekávání. S využitím navržené laboratoře proběhly subjektivní testy kodeku G.711 na 10 osobách.
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Analysis of the dependence of communications services to the delay and QoS optimization
Schön, Martin ; Číka, Petr (referee) ; Hošek, Jiří (advisor)
This thesis discusses wireless network standards 802.11a/b/g/n. First part explains basic principles of networks and media access. Next the standard IEEE 802.11, general QoS parameters and their application in wireless networks, according to standard 802.11e are analyzed. Second part of the thesis verifies the acquired knowledge in simulating program Opnet - effects of the delay, jitter and packet loss on VoIP call are tested. In the last part of the thesis a network for video streaming has been designed. The video was streamed in different qualities and the influence of other network traffic (with and without the support of QoS) on the video streaming was tested.
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Measurement of data network transmission parameters
Haško, Juraj ; Jeřábek, Jan (referee) ; Zeman, Václav (advisor)
This bachelor thesis focuses on the analysis of possible methology description of met- hods for measuring transmission parameters of data networks, and comparison of the measuring methodology for determining the appropriateness of use before a certain type of network. It includes a proposal workplace for measurement of transmission parameters.
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Diagnosing Parkinson's disease from analysis of speech recording
Vymlátil, Petr ; Trzos, Michal (referee) ; Lněnička, Jakub (advisor)
This thesis is focused on diagnosing Parkinson’s disease from analysis of speech recording. Introduction of this work deals with description of voice production mechanism, it’s basic qualities and influence of hypokinetic dysarthria on speech. In next chapter, there is described voice signal and some methods of it’s preprocessing. Next part continues dealing with description of chosen individual symptoms, which are needed for PD diagnosing, followed by definition of chosen reduction methods and classifiers. There is a comparison of classify succes of naive bayes classifier, depending on chosen reduction method in last chapter of this work.
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Verification of stable next generation networks via transmission parameters measurement
Gregor, Lukáš ; Čučka, Milan (referee) ; Grenar, David (advisor)
This thesis deals with the measurement of transmission parameters in the new generation access networks NGA. The aim of the thesis is to build and configure a test network and scenarios for the measurement of service quality parameters and then verify the transmission stability. The theoretical part describes general functioning of NGN networks, the requirements of different telecommunications services on quality parameters, methodology and recommendations for measuring transmission parameters in packet networks. The practical part deals with the configuration of scenarios using mainly MPLS technology and methodology of their testing. Measurements were performed according to recommendations IETF RFC 2544, IETF RFC 6349 with the ExacTCP test and ITU-T Y.1564 with the EtherSAM test. For measurements were used measuring instruments of EXFO brand. In conclusion, the measurement results according to the mentioned standards were evaluated and also the advantages of using the measurement according to the given standard in NGA access networks were discussed.
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Diagnostic tool for RTP sessions
Sirotný, Miroslav ; Komosný, Dan (referee) ; Šimek, Milan (advisor)
This work was divided into two parts. In the first part are worked out protocols RTP and RTCP with theory. In this part I show to what these protocols are used. The second part is dedicated to proposal of application for the diagnosis of transmission parameters RTP / RTCP relations. Programs like Tcpdump win, Wireshrak, IP / TV Viewer and the Java programming language with development setting NetBeans 5.5.1. were used while creating the application. In this part we focused mainly at two important parameters like Jitter and Packet Loss.Functionality applications. Finally, we have verifed the function of the application on Multicast Network with running IPTV.
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Measurement of transfer speeds and delays in computer networks
Bárdossy, Adrián ; Kubánková, Anna (referee) ; Jeřábek, Jan (advisor)
Bachelor thesis is interested in measurement of transfer rate and latency in computer networks. In the first part of thesis is defined, which motodics of measurement we know, various RFC and their specifications, also various parameters about measurement in computer networks like bit rate, capacity of channel, latency. In the second part are prepared users interfaces and softwares for applying the measurement of thesd parameters. In the last part is application of these softwares and creating and testing methodic of network measurement.
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VoIP and QoS
Kolmačka, Jan ; Křivánek, Vítězslav (referee) ; Kovář, Petr (advisor)
The bachelor’s thesis gives the basic information about the solution of a problem with Quality of Service in sequence with the VoIP telephony. In a few last years the VoIP technologies and basically the other multimedia applications have unbelievable grow. It is caused by a big demand internet user’s for the new interactive applications offering voice transfers and streaming video. These new habits bring quite big requests on networks from the side of QoS. That is why, it was necessary to develop new methods, which reach requested parameters of QoS in single categories. The first part discuss theoretically about protocols used in the VoIP telephony. The second part presents QoS, parameters of QoS and two basic methods for guarantee QoS. In the last part of the bachelor’s thesis is theoretically described the QoS support in Wi-Fi with the main aim on new technologies QoS reservation defined in the 802.11e. The following simulations and the results of the different settings parameters QoS are made by the powerful simulating software Opnet Modeler.
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Performance and security analysis of Wireguard technology
Varga, Oliver ; Holasová, Eva (referee) ; Krajsa, Ondřej (advisor)
This thesis deals with the description of WireGuard virtual private networks technology, its comparison with the technologies IPsec and OpenVPN based on the encrpytion algorithms they use to ensure security and also compares their technical parameters such as latency, jitter and transfer speeds. The work includes a description of the WireGuard technology, a comparison of the mentioned technologies and finally the results of the measurements of their technical parameters. The methodology chosen by us for testing the parameters, the hardware used to obtain the results and the network topology are also described. Finally, the results obtained from the tests are compared.
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