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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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Digital Image Watermarking
Al Zaid, Abdullah Saleh ; Říha, Kamil (referee) ; Číka, Petr (advisor)
This is the Final Project Report as being composed of an extensive summary of activities and results made by the student Abdullah S. A. Alzaid while undertaking the Watermark Project. This project acquaints an algorithm of digital watermarking which is based on Discrete Cosine Transform(DCT) and Discrete Wavelet Transform(DWT). In accord with the characters of human vision, the main objective of the project is to be focused on developing an image watermarking algorithm by taking advantage of both the DCT and DWT transforms and analysis of the algorithm on the basis of invisibility, distortion and robustness to attacks. The simulation results show that this algorithm is invisible and has good robustness for some common image processing operations. By the use of Matlab software, the two structures have been coded and then implemented.
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GPS Location based Information Provision in IMS subsystem
Šišák, Vladimír ; Müller, Jakub (referee) ; Číka, Petr (advisor)
This thesis deals with an introduction of new functionalities in communication via IP Multimedia Subsystem (IMS) at the beginning. There are described functions of each part and introduced protocols which are used by this system. Thesis presents the method of positioning with Global Positioning System (GPS) together with methods for the distance measuring of two points on the Earth. Services provided by IMS are developed in Service Development Studio which is shortly mentioned too. The developed service is divided into two parts: a client side part and a server side part, which is formed like a servlet. This program component, which is running on server is mentioned at the end of teoretical part. The procedure of service creating, setup and functions are in description of the created service, which provides informations based on geographical coordinates to user, is described after the teoretical part.
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Digital filters for image processing
Všetička, Václav ; Říha, Kamil (referee) ; Číka, Petr (advisor)
This work is dedicated to methods for editing the digital image. When you need an suitable algorithm to highlight the desired information from the image, or conversely, suppress disturbing elements in the picture. This work describes a few most basic image editing filters to use common in technical and medical practice. The result of this work are implementing some filters into Java.
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Modern compression formats of digital image
Eder, Radek ; Přinosil, Jiří (referee) ; Číka, Petr (advisor)
This bachelor thesis deals with the problems of digital image compression. There are described basic color models RGB and YCbCr and conversion between them. Described are currently used codecs for digital images. JPEG compression format is discussed in more detail, which currently is still the most widely used format for digital photos. Described is a process of digitizing the image using the JPEG standard, which includes sampling, quantization and coding. Described are also formats JPEG2000, PNG and WebP. End of chapter are described methods for subjective and objective evaluation of the quality of digital image compression. Among the subjective methods include Double Stimulus Impairment Scale (DSIS) and Double Stimulus Continuous Quality Scale (DSCQS), then the objective methods include Mean Squared Error (MSE), Peak Signal to Noise Ratio (PSNR) a Structural Similarity (SSIM). Application was created as part of the work that allows you to compress the source image to the selected formats. It also allows a qualitative evaluation of compression and store the results to the file.
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Video compression based on wavelet transform
Kintl, Vojtěch ; Číka, Petr (referee) ; Malý, Jan (advisor)
This diploma thesis focuses on current possibilities concerning the employment of wavelet transformation for video signal compression. One part of the work is devoted to the necessary execution of this task in practise. This deals with video signal and its features description, wavelet transformation and compression methods. The second part concentrates on description of selected compression method. It is the SPIHT (Set Partitioning In Hierarchical Trees) algorithm which is intended for compression of static image data. The algorithm is modified for usage with video signal compression which is specific for its time redundancy. The algorithm is called 3D SPIHT as it works in the spatial and time domain. The algorithm is implemented in the MATLAB programming environment which provides a sophisticated support for wavelet transformation (Wavelet Toolbox). To provide a simple and intuitive encoder control there has been developed an application delivering graphical user interface (GUI). On displayed image previews and measured graphs the user can change encoder parameters and monitor performed changes. There are four image test-sequential modes containing various scenes with different features. The final part of the work is focused on testing of the proposed encoding scheme, various image test-sequential modes and encoder settings. Measured values are graphically displayed and analyzed.
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Videoconference potentials in PBX Asterisk
Vlk, Bronislav ; Číka, Petr (referee) ; Krajsa, Ondřej (advisor)
This thesis deals with the possibilities of video conferencing in Asterisk PBX and their use in practice. They also described the contingencies and how its configuration. Particular attention is paid to the protocols SIP, IAX and H.323, which are described in one of the chapters. The thesis was created by the Asterisk PBX, which demonstrates cooperation with videoconferencing clients. The thesis describes the configuration files so that the central set. Conclusion the work assesses the use of codecs for different clients.
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Design of power supply for ADAHRS
Andrysík, Lukáš ; Vrba, Kamil (referee) ; Číka, Petr (advisor)
This master’s thesis contains basic description od ADAHRS system, DO-160 standard and mainly focuses on power supply desing with supercapacitors backup. It initialy deals with power supply requirements and continues with block diagram and multiple 5 V supply solutions. For selected 5 V supply it describes more deeply its properities and options. As the main theme it deals with providing power supply backup using supercapacitors – selecting particular method and configuring supercapacitor charging/discharging controller. It also includes tolerance and stress analysis of the components used in design. Lastly it describes testing of the final product.
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Videoconferencing Application
Jandera, Pavel ; Šmirg, Ondřej (referee) ; Číka, Petr (advisor)
Videoconferencing is a modern way of communication, in which the participants carry picture and sound and during transmission can also exchange various data. The aim of this work is to create an application for the connection of up to eight participants to videoconferencing and create a web interface to facilitate configuration of this application. Videoconferences types and the feasibility are described in the first part of this work. Furthermore, the SIP (Session Initiation Protocol) protocol used to production of multimedia sessions is described. RADVISION IVP system was selected to the implementation of videoconferencing application. IVP is a complex system for the operation of videoconferencing, which allows implementing and operating various types of services. Basic components of system are described in next section of this work. Second part of this work describes interface for applications creating that IVP offers to programmers. The main part of this work is the design and implementation of video conferencing application that is realized as an IVP service. There is described the implementation and testing. A web interface to facilitate the configuration of video conferencing applications has been designed and implemented. This interface also allows the service provider to manage user accounts. The web interface was implemented in Java EE.
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Automated Hydroponic System
Borsuk, Adam ; Kolařík, Martin (referee) ; Číka, Petr (advisor)
The aim of the bachelor thesis is to study the design and creation of an automatic hydroponic system for plant cultivation and to solve the creation of components of the system according to the basic conditions for plant growth and subsequently to test and verify their properties, to evaluate their functionality. The second goal is to create a communication interface for sending and storing data from the system while creating a transparent display of stored and up-to-date data. The third objective is to verify the functionality and stability of the selected microcontroller as a control unit.
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