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Axisymmetric antennas with metamaterials
Roman, Pavel ; Fiala, Pavel (referee) ; Raida, Zbyněk (advisor)
This project is focused on computer modeling of so-called meta-materials, and on the exploitation of metamaterials in the design of electrically small antennas. For modeling, COMSOL Multiphysics 3.3 was used. Simulations were focused on impedance matching of antennas. Antennas with metamaterials were compared with corresponding conventional antennas without metamaterial layers. The project does not investigate the creation of metamaterials; the project concentrates on their influence on crucial parameters of antennas. Next step this project is focused on optimalization this structure in program Matlab version R2009b. We used optimalization method PSO (swarms of particles) and results are comparing whit results calculating in COMSOL program.
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Variable segmentation for sound signal processing
Garai, Szabolcs ; Míča, Ivan (referee) ; Balík, Miroslav (advisor)
This paper describes the methods used mainly in the filtration of audio signals -- noise reduction. It realizes segmentation with variable lenght of segment, constant overlap add and segmentation with variable lenght of segment and overlap add. These methods are then compared with comon methods of segmentation in dependance of the lenght of segment and used window function by the thresholding method. For this purpose it uses the database of audio records. In the first part it desrcibes the technique of audio signal processing with comon method of segmentation. According to this method it continues in design of signal processing by variable segmentation method, in which it is needed to modify the shape of window function, which influences and attributes are explained in next chapter. In practical part it describes the implemented methods in MATLAB programming language with each steps of testing. It continues with chart of enclosed files and the evaluation of the results of hearing tests.
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Utilizing psychoacoustic model and Wavelet Packet Transform for purposes of audio signal watermarking
Heitel, Tomáš ; Schimmel, Jiří (referee) ; Rajmic, Pavel (advisor)
This Thesis deals with a method to enforce the intellectual property rights and protect digital media from tampering – Digital Audio Watermarking. The main aim of this work is implement an audio watermarking algorithm. The theoretical part defined basic terms, methods and processes, which are used in this area. The practical part shows a process of embedding the digital signature into a host signal and her backward extraction. The embedding rule used spread spectrum technique and a psychoacoustic model. The implemented psychoacoustic model involves two properties of the human auditory system which are frequency masking and representation the frequency scale on limited bands called critical bands. The model is relatively new and based on the DWPT. In terms of above model is then the digital watermark embedded in the wavelet domain. This algorithm is implemented in technical software MATLAB. One part of this work focuses on robustness tests of the algorithm. Common signal processing modifications are applied to the watermarked audio as follows: Cutting of the audio, re-sampling, lossy compression, filtering, equalization, modulation effects, noise addition. The last part of the thesis presents subjective and objective methods usable in order to judge the influence of watermarking embedding on the quality of audio tracks called transparency.
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Model of computer network in MATLAB/SIMULINK environment
Zedníček, Petr ; Zeman, Václav (referee) ; Kolka, Zdeněk (advisor)
The bachelor thesis deals with simulation of TCP protocol behaviour in Wireless optical environment. The thesis examines the various parameters of the protocol and evaluates their response to the transmission speed. The key objectives of the thesis are the introduction to the problems of communication, specially the description of the transport layer architecture, TCP / IP and congestion management mechanism NewReno. A large part of the thesis is devoted to modelling communication points and a model of optical wireless connections. The results will be applicable to create a new communication protocol for Wireless optical environment.
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Modern methods of multimedia teaching
Mazal, Zdeněk ; Přinosil, Jiří (referee) ; Pfeifer, Václav (advisor)
The work is a summary of the advantages and disadvantages of e-learning, the next section deals with search keywords in sound record, where the survey methods used, operating search engines, their division and the possibilities of use. It also includes the design, implementation and results of the success of a simple search engine of the words in sound record, programmed in Matlab Environment.
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Control of Quadrotor
Tesáček, Zdeněk ; Grepl, Robert (referee) ; Šolc, František (advisor)
This master’s thesis deals with the design and optimization of the quadrotor stabilization control. The basic physical properties and technical aspects of this specific device are illustrated using the NANOKOPTER platform. Dedicated mathematical model of quadrotor was implemented in MATLAB/Simulink environment to emulate the behavior and characteristics of real quadrotor. Based on this model a feasible method of stabilization control by means of state controller was conceived and developed. The proposed solution utilizing state controller was incorporated into the stabilization control procedures of the NANOKOPTER testing platform and its functionality successfully verified during field trials.
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Paralinguistic signals recognition in spoken dialogs
Mašek, Jan ; Míča, Ivan (referee) ; Atassi, Hicham (advisor)
This document describes the three methods for the detection and classification of paralinguistic expressions such as laughing and crying from usual speech by analysis of the audio signal. The database of records was originally designed for this purpose. When analyzing everyday dialogs, music might be included, so the database was extended by four new classes as speech, music, singing with music and usual speech with background music. Feature extraction, feature reduction and classification are common steps in recognizing for all three methods. Difference of the methods is given by classification process in detail. One classification of all six classes at once is proposed in the first method called straight approach. In the second method called decision tree oriented approach we are using five intuitive sub classifiers in the tree structure and the final method uses for classification emotion coupling approach. The best features were reduced by feature evaluation using F-ratio and GMM classifiers were used for the each classification part.
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Network Element with Advanced Control
Zedníček, Petr ; Kacálek, Jan (referee) ; Škorpil, Vladislav (advisor)
The diploma thesis deal with finding and testing neural networks, whose characteristics and parameters suitable for the active management of network element. Solves optimization task priority switching of data units from input to output. Work is focused largely on the use of Hopfield and Kohonen networks and their optimization. Result of this work are two models. The first theory is solved in Matlab, where each comparing the theoretical results of neural networks. The second model is a realistic model of the active element designed in Simulink
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Advanced objective measurement criteria applied to image compression
Šimek, Josef ; Průša, Zdeněk (referee) ; Malý, Jan (advisor)
This diploma thesis deals with the problem of using an objective quality assessment methods in image data compression. Lossy compression always introduces some kind of distortion into the processed data causing degradation in the quality of the image. The intensity of this distortion can be measured using subjective or objective methods. To be able to optimize compression algorithms the objective criteria are used. In this work the SSIM index as a useful tool for describing the quality of compressed images has been presented. Lossy compression scheme is realized using the wavelet transform and SPIHT algorithm. The modification of this algorithm using partitioning of the wavelet coefficients into the separate tree-preserving blocks followed by independent coding, which is especially suitable for parallel processing, was implemented. For the given compression ratio the traditional problem is being solved – how to allocate available bits among the spatial blocks to achieve the highest possible image quality. The possible approaches to achieve this solution were discussed. As a result, some methods for bit allocation based on MSSIM index were proposed. To test the effectivity of these methods the MATLAB environment was used.
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Enhancement of bio-medical image signals
Gregor, Michal ; Šmirg, Ondřej (referee) ; Přinosil, Jiří (advisor)
When scanning biomedical images by magnetic resonance or ultrasound, unwanted elements in the form of noise are entered to the image. With help of various methods it is possible the noise from the image partially remove. There are many methods for noise reduction and every one works on a different principle. As a result of this the results of these methods are different and is necessary for them to be objectively assessed. There is use for the adjustment of the images wavelet transformation and some treshold techniques in the work. The quality of the resulting pictures is tested by the methods for objective quallity tests. Testing was done in the MATLAB program environment on the pictures from magnetic resonance and pictures from ultrasound.
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