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Analysis of Speech Signals in VoIP Transferred Over a Network Channel
Báňa, Josef
The article 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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Free-Space Optics data link
Šála, Jakub ; Číž, Radim (referee) ; Šporik, Jan (advisor)
In this thesis, shows a current issue for free space optics, limiting their use in practice with regard to the availability and reliability. They conducted measurements on wireless optical links and the observed values is calculated by the availability of the connection. Subsequently, measurements are performed on alternate versions of wireless and copper connections. Observed values were compared with a wireless optical link. It is made of optical design of wireless connections at home.
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Optimalization and analysis of communication services latency dependencies
Zikmund, Lukáš ; Škorpil, Vladislav (referee) ; Endrle, Pavel (advisor)
This master’s thesis is focused on ensuring of Quality of Service (QoS) in wireless network for standards IEEE 802.11 a/b/g/n. First part of this thesis is focused on the theory of this issue. It covers methods of data transfer in computer networks and individual transfer parameters especially on parameters needed to ensure quality of service. It also describes standards for wireless data transmission and protocols for real time data transmission. The second part is devoted to OPNET modeler and to simulations created on this program. Simulations are focused on real-time data transfer and compare the standards in terms of delay and jitter.
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State of the art speech features used during the Parkinson disease diagnosis
Bílý, Ondřej ; Smékal, Zdeněk (referee) ; Mekyska, Jiří (advisor)
This work deals with the diagnosis of Parkinson's disease by analyzing the speech signal. At the beginning of this work there is described speech signal production. The following is a description of the speech signal analysis, its preparation and subsequent feature extraction. Next there is described Parkinson's disease and change of the speech signal by this disability. The following describes the symptoms, which are used for the diagnosis of Parkinson's disease (FCR, VSA, VOT, etc.). Another part of the work deals with the selection and reduction symptoms using the learning algorithms (SVM, ANN, k-NN) and their subsequent evaluation. In the last part of the thesis is described a program to count symptoms. Further is described selection and the end evaluated all the result.
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Quality of services and experience qualify for next generation networks
Vaněk, Jiří ; Horváth, Tomáš (referee) ; Grenar, David (advisor)
The thesis sums up the traffic parameters for the evaluation of next-generation access networks. There are mentioned parameters for service quality management and parameters for measuring the quality of experience. The EU regulation on High Speed Internet in the Czech Republic is analyzed. The practical part compares the results between the implementation of the quality management of services and without implementation. Also there is comparing theoretical and practical transmission rates of physical ports. Part of the thesis is a questionnaire focused on the quality of experience of the video sequence.
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Open-Source Software Tools for Network Diagnostics
Loffay, Pavol ; Ráb, Jaroslav (referee) ; Matoušek, Petr (advisor)
The aim of this work is to make a research of existing open source tools, which are concerned with the diagnosis of the network transmission in the form of measuring of throughput and other basic parameters. The work is devoted to the construction of methodics for testing and comparing devices between themselves. The result of the work is recommendation to an ordinary customer the right application for measuring of given network transmission parameter.
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Methods for measurement of data network performance and quality parameters
Sukup, Luboš ; Zeman, Václav (referee) ; Novotný, Vít (advisor)
Master thesis involves the development of quality measurement issues and performance parameters in data networks. It describes the main technologies as they affect the quality and performance parameters and the effect of these parameters for voice, video and data services. Next are listed some methods for measuring parameters of the data network.In the practical part is selected one method of measuring network parameters and properties of this method are demonstrated by illustrative examples.
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Laboratory of Quality of Service
Eltahir Ahmadon, Ahmed ; Kolka, Zdeněk (referee) ; Polívka, Michal (advisor)
The Bachelor's work, you are reading, deals with the issue of VoIP calling and measurement its quality. In the following paragraphs the discussion will be about the basics of networking protocols such as TCP, UPD, IP and SIP, after that a preliminary introduction to QoS issues - ways of measuring voice quality for instance MOS and E-Model. Importance of implementing QoS for VoIP, and QoS parameters used in the proposed services (will be called "mechanisms"), such as Best effort service, Integrated and Differentiated services. Based on these fundamentals points with designed laboratory for quality of service. The laboratory will be aimed at testing the quality of codecs with regard to bandwidth, jitter, delay and packet loss. The solution lies in the fact that, which codecs are actually suitable for the service.
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Wireless communication link analyzer
Dostálek, Jakub ; Burian, František (referee) ; Jílek, Tomáš (advisor)
The aim of this bachelor thesis is to design and implement a wireless communication analyzer in mobile robotics, using IPv4 protocol and Ethernet interface and to create correctly selected and expressed characteristics from the measured data, according to which the wireless communication channel can be further optimized for the best data transmission. To meet these requirements, a brief search of existing solutions was performed, their applicability was discussed and important parameters of the wireless transmission channel were defined, which will form the given characteristics. Furthermore, the actual design and implementation of a wireless communication link analyzer for previously specified required parameters, verification of its functionality on the transmission link with known parameters and automation of measurement and data evaluation was performed.
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Analysis of delay dependence of modern communication services and channels, QoS optimization
Rozman, Jiří ; Szőcs, Juraj (referee) ; Endrle, Pavel (advisor)
The main aim of this thesis is to familiarize with options of services using real-time data transfer in wireless networks. Theoretical part presents wireless network based on IEEE 802.11 standard and its practical use. Large part is focuses on 802.11e standart, that provides support for quality of service in wireless networks. Furthemore this thesis deals with transport and applicaton protocols supporting multimedia streaming over computer network. Second chapter is focused on analyzing real computer network with purpose in measuring parametrs influencing quality of service such as bandwith, delay, jitter and loss. Last part deals with the design of wireless network in OPNET Modeler enviroment with focus on simulating parameters that influence quality of service.
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