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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Železem funkcionalizované nanočástice oxidu titaničitého / Iron Functionalized Nanoparticles of Titanium Dioxide

Volfová, Lenka January 2017 (has links)
Diploma thesis Iron Functionalized Nanoparticles of Titanium Dioxide Lenka Volfová 2017, ABSTRACT Iron-functionalized TiO2 were obtained by hydrolysis of aqueous solutions of titanyl sulfate with addition of ferric nitrate with ammonium hydroxide and the reaction filtered and washed with hydrogen peroxide. The colloid solutions thus prepared were lyophilized and the products were subsequently annealed at three different temperatures of 650 řC, 800 řC and 950 řC. The prepared doped materials were characterized by powder X-ray diffractometry, electron microscopy, infrared spectroscopy, Mössbauer spectroscopy, UV/VIS spectroscopy, thermogravimetric analysis and differential thermal analysis, and measurement of the specific surface area. Photocatalytic activity was determined by measuring of the decomposition of kinetics of 4-chlorophenol in an aqueous solution in the ultraviolet and visible area. For comparison of activity in the UV area and in the visible area were used a previously prepared highly photoactive specimen and standard TiO2 from Kronos, respectively. Keywords: Doped titanium dioxide, nanostructure, X-ray diffraction, electron microscopy, Mössbauer spectroscopy, suppression of photoactivity
12

Zpracování digitální fotografie / Digital Photo Processing

Zdražil, Vít Unknown Date (has links)
This document focuses on processing of RAW image data from digital cameras. In first section is described principle of image capturing by digital camera, common way of image processing in the device and what the RAW format is, its pros and cons. In the next section is described existing demosaicing methods, methods for additional processing of RAW image data and there is analyzed specific RAW format, Canon's CR2, including structure and guide for its conversion. Next sections contains proposal of the new improved demosaicing method and method for suppressing digital noise. On this basis a library for basic CR2 files processing was implemented. There is comparison of methods for processing RAW image data with this library in the next section. In the conclusion there is summary of finished work and there is also mentioned outline of future work.
13

Vliv proteinu HBx viru hepatitidy B na aktivaci MEK1/2-ERK signalizace a inhibici IFN typu I v hepatocelulární linii Huh7 / Effect of HBV protein HBx on activation of MEK1/2 signaling and inhibition of type I IFN in hepatoma cell line Huh7

Berehovska, Olena January 2019 (has links)
Hepatitis B virus (HBV) infection is one of the major causes of chronic and cancerous liver disease. Elimination of HBV from chronically infected patients by recombinant interferon α (IFNα) monotherapy shows that the mechanisms of the innate immunity play an important role in suppressing viral infection. However, the mechanisms of recognition of the HBV genome and its escape from the mechanisms of natural immunity are still little known. One of the principal factors enabling the virus to escape from cellular restriction mechanisms is the HBx viral protein. HBx is a 154 amino acid pleiotropic multifunctional protein affecting transcription, signal transduction, cell cycle, protein degradation, apoptosis, and chromosomal stability in the host cell. Previous results from our laboratory have shown that activation of the MEK1/2-ERK signaling pathway in plasmacytoid dendritic cells leads to inhibition of IFNα production. The aim of my work was to determine whether HBx activates the MEK1/2-ERK pathway and thus inhibits IFN type I production also in hepatocytes. For this purpose, I monitored HBx production in the Huh7 hepatoma cell line by transfecting the bicistronic plasmid pHBx- IRES-EGFP and Western blotting. Using the same method, I monitored activation of the MEK1/2-ERK signaling pathway by ERK...
14

Trychtýřová anténa s potlačenými bočními laloky / Horn antenna with suppressed side-lobe radiation

Kaděra, Petr January 2018 (has links)
This master´s thesis is focused on the ways of possible realisation of the directive horn antenna with suppressed side lobes in the frequency bands 71-76 GHz and 81-86 GHz. In this thesis a detailed research of the feasible options including parameters comparison and assessment of pros and cons of the particular solutions has been performed. Among the specified technical requirements, the emphasis has been placed on the manufacturing options and low cost availability of the materials applicable for the given antenna. The main part of the thesis deals with the conical horn antenna loaded with a hyperbolic dielectric lens, further the antenna with flat dielectric lens based on a transmitarray and also the integrated elliptical lens antenna. The following part of the thesis deals with the possibilities of characterizing the properties of the dielectric material of the lens.
15

Metoda potlačení interferencí Wigenrovy-Villeovy distribuce / A Method to Supress Interferences in Wigner-Ville Distribution

Pikula, Stanislav January 2019 (has links)
The doctoral thesis focuses on signal representation in the time-frequency domain with constant resolution. In theoretical introduction the possibilities of displaying a signal in time and frequency are summarized. Attention is concentrated on comparison of short-time Fourier Transform (STFT) and Wigner-Ville Distribution (WVD). The latter achieves a significantly better resolution, especially for a linearly modulated signal. The disadvantage of WVD, which is the presence of interferences resulting from the calculation of the instantaneous autocorrelation function, is described in detail. These interferences are due to the presence of multiple components in the signal or its non-linear modulation. Subsequently, several methods are discussed, which can suppress these interferences, but at the cost of resolution loss. One of the interference suppression methods is smoothed pseudo Wigner-Ville distribution. It is further used in this thesis for the analysis of interference suppression when various filtrations in the time-frequency plane are applied. Several signals with multiple components or various non-linear modulations are used. Based on the analysis, a method using a set of variously smoothed pseudo Wigner-Ville distributions is designed to estimate the time-frequency representation with high resolution and minimal interferences. To compare the results to other methods, the quantitative metrics used in the literature are compared. To select the appropriate one a new metric is suggested. It is applicable to simulated signals and uses mean square error. Based on the comparison, the Stankovi\' measure is selected as the most appropriate for comparing results. The selected metric is used to determine the appropriate minimal number of differently smoothed pseudo Wigner-Ville distributions. Using the selected metric, the proposed method is compared with other methods. These are STFT with optimized window length, S-method with optimized parameter and optimization method using radial Gaussian kernel (RGK). These methods are compared based on the set of signals previously used for interference suppression analysis. In addition, noises are added to the signals. Finally, the methods are also compared based on the real bat echo signal. In conclusion, the proposed method outperforms the compared methods in suppressing interference and resolution.
16

Zesilovač pro tenzometry / Strain Gage amplifier

Kneblík, Adam January 2008 (has links)
The thesis deals about method of gain signals from strain gauge bridges. There are mentioned some signal conditioning methods for bridges amplifiers and charactered their properties. In the next part of this thesis are calculated the amplifier errors for various temperature. There are projected individual variants of strain gage amplifiers (instrumentation amplifier AD524, isolation amplifier, switched capacitor based instrumentation amplifier), their properties are compared with strain gage amplifier Vishay P-3500.
17

Metody potlačení strukturního šumu typu spekle / Speckle noise suppression methods in ultrasound images

Tvarůžek, Marek January 2013 (has links)
This diploma thesis deals with the methods of despeckling in ultrasound images. Ultrasound imaging and related artifacts are described in more details. Ultrasound imaging has its pros and cons, where speckle noise is a disadvantage to be solved. Models of origin of this specific noise are referred too. Practical part of this thesis aims on filtering speckled images by basic and advanced filtering methods as are linear filtering, median filtering, application of Frost filter, QGDCT, geometric filtering, anisotropic diffusion filtering and filtering based on wavelet transformation. Results are compared on the basis of objective criteria.
18

Eliminace zkreslení obrazů duhovky / Suppresion of distortion in iris images

Jalůvková, Lenka January 2014 (has links)
This master`s thesis is focused on a suppression of a distorsion in iris images. The aim of this work is to study and describe existing degradation methods (1D motion blur, uniform 2D motion blur, Gaussian blur, atmospheric turbulence blur, and out of focus blur). Furthermore, these methods are implemented and tested on a set of images. Then, we designed methods for suppression of these distorsions - inverse filtration, Wiener filtration and iterative deconvolution. All of these methods were tested and evaluated. Based on the experimental results, we can conclude that the Wiener-filter restoration is the most accurate approach from our test set. It achieves the best results in both normal and iterative mode.
19

Objektivní měření a potlačování šumu v hudebním signálu / Objective assessment and reduction of noise in musical signal

Rášo, Ondřej January 2013 (has links)
The dissertation thesis focuses on objective assessment and reduction of disturbing background noise in a musical signal. In this work, a new algorithm for the assessment of background noise audibility is proposed. The listening tests performed show that this new algorithm better predicts the background noise audibility than the existing algorithms do. An advantage of this new algorithm is the fact that it can be used even in the case of a general audio signal and not only musical signal, i.e. in the case when the audibility of one sound on the background of another sound is assessed. The existing algorithms often fail in this case. The next part of the dissertation thesis deals with an adaptive segmentation scheme for the segmentation of long-term musical signals into short segments of different lengths. A new adaptive segmentation scheme is then introduced here. It has been shown that this new adaptive segmentation scheme significantly improves the subjectively perceived quality of the musical signal from the output of noise reduction systems which use this new adaptive segmentation scheme. The quality improvement is better than that achieved by other segmentation schemes tested.
20

Využití moderních metod zvyšování spolehlivosti pro implementaci řídicího systému / Usage of Modern Methods for Increasing Reliability of Control System Implementations

Szurman, Karel January 2012 (has links)
At avionics control and critical systems is necessary guarantee a minimal level of fault tolerance and their high reliability. On the electronic components in these devices has an undesirable influence environment conditions and mainly cosmic ray. In this paper are described the most common failure types of semiconductor components and devices together with modern methods which can be increased the system fault tolerance and its overall reliability. There are introduced aspects of the avionic systems design due to finally certification and ways to evaluate its safety. This thesis describes design and implementation of the CAN bus control system for the FPGA platform which uses the CANAerospace application protocol. Created system design is improved by the TMR architecture. Fault tolerance of both system version is tested by the SEU framework which allows using the dynamic partial reconfiguration generate an SEU failures into running FPGA design.

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