Global ETD Search

331	Vliv frekvenčního měniče na životnost ložisek a jejich poškození / The influence of the frequency converter on the life and damage of bearings Sukovatý, Adam January 2018 (has links) This thesis deals with the effect of frequency inverter on the lifetime of roller bearings. The measurement has been carried out on the frequency inverter and induction motor by Siemens in the Switchgear laboratory of Fakulty of elektrical engineering and communication. Data has been recorded and processed on Adash VA4 Pro analyzer. Methods of measuring RMS values and frequency analysis of vibration and current were used for the analysis. Based on the mutual similarity of frequency spectrum, the presence of the high frequency capacitive current in the bearings has been proven. To prevent this, possible solutions have been presented. In the second part of the experiment an effect of changing pulse width modulation (PWM) on vibration was examined. The goal was to make a basic analysis and to provide background material for further research.
332	Zpracování signálu z akcelerometru na měření vibrací / Acccelerometer signal processing for vibration measurement Marčišovský, Peter January 2020 (has links) Táto diplomová práca sa zaoberá návrhom zariadenia schopného vysoko presného merania vibrácií za použitia piezoelektrického akcelerometra. Zariadenie je určené na vyhodnocovanie zdravotného stavu strojov, najmä elektrických strojov ako elektromotor, veterná turbína a iné. Za účelom dosiahnutia vysoko presného a vysoko lineárneho merania v spektre extrémne nízkych frekvencií siahajúcich až ku jednosmerným napätím, cez sub-hertzové pásma po desiatky hertzov, ale aj vo vyšších frekvenciách, bola vyžadovaná možnosť použitia prístupu s jednosmernou väzbou zvaného "posúvanie napäťovej úrovne" a následné vyhodnotenie a porovnanie prístupu so striedavou väzbou, ktorý sa bežne používa pre pripojenie piezoelektrického akcelerometra.
333	Alternativní metody a algoritmy pro detekci plamene / Alternative methods and algorithms for flame detection Kozubík, Kamil January 2008 (has links) This master’s thesis deals with flame detection methods. The purpose of the project was to create a flame detector, which uses the alternative method of flame detection. The introduction of this thesis gives the summary overview of the existing methods for flame detection. Further, the existing flame detectors and their applications are described. Two alternative algorithms for flame detection which are based on the digital signal analysis were realized on the PC. Flame detector, which utilizes the digital analysis of audio signal, was realized on 8 bit microcontroller Atmega128 and achieved results are presented.
334	Diagnostika vibrací elektromagnetického původu v asynchronním motoru / Diagnosis of electromagnetic origin vibrations in asynchronous motor Koníček, Pavel January 2014 (has links) The aim of this master´s thesis is to introduce methods of diagnostics of vibrations in electrical machines. Describe the various vibration sources located inside and outside of the electric machine. Description of the sources of vibration is then preferably dedicated to vibration of electromagnetic origin. There is a description of the construction of an asynchronous motor and the magnetic circuit, the theory of vibrations and their origin. Described are also vibration sensor enables measurement and mathematical tools for their evaluation. In this work also practical vibration measurements on an asynchronous motor, data processing, their subsequent analysis and computer simulation of electromagnetic vibration origin. The conclusion of this work is devoted to the evaluation of the data obtained.
335	Verifikace metadat zvukových záznamů / Vefication of Metadata for Sound Recordings Přerovský, Petr January 2012 (has links) The work deals with verification of the metadata of audio recordings in an environment of mobile phones running Android. The text work is divided into three main parts. The first part is focused more on theoretical basis, where the main emphasis on the description of Android, application structure, description of the audio MP3 file and theoretical basis of Fourier transform in signal processing. The second part is devoted to solution design, analysis and implementation. The third part deals with testing.
336	Utilisation des signaux du cerveau (EEG) et vocaux pour la détection et le monitoring des facultés d'une personne Ben Messaoud, Aymen January 2020 (has links) (PDF) No description available. Alcool Auto Automobile Cannabis Cerveau Classification Communication Conduite Convolutif Convolutionnel Détection Dysarthrie EEG Électroencéphalographie Élocution Faculté FFT Français Humain LPC LPCC MEL MFCC Parole PLP Signal Son Véhicule Vocal Voix Voyelle
337	Time Frequency Analysis of ERP Signals / Time Frequency Analysis of ERP Signals Bartůšek, Jan January 2007 (has links) Tato práce se zabývá vylepšením algoritmu pro sdružování (clustering) ERP signálů pomocí analýzy časových a prostorových vlastností pseudo-signálů získaných za pomocí metody analýzy nezávislých komponent (Independent Component Analysis). Naším zájmem je nalezení nových vlastností, které by zlepšily stávající výsledky. Tato práce se zabývá použitím Fourierovy transformace (Fourier Transform), FIR filtru a krátkodobé Fourierovy transformace ke zkvalitnění informace pro sdružovací algoritmy. Princip a použitelnost metody jsou popsány a demonstrovány ukázkovým algoritmem. Výsledky ukázaly, že pomocí dané metody je možné získat ze vstupních dat zajímavé informace, které mohou být úspěšně použity ke zlepšení výsledků.
338	Design of Multi-Beam Hybrid Digital Beamforming Receivers Madishetty, Suresh January 2018 (has links) No description available. Electrical Engineering Computer Engineering Microstrip patch antennas Antenna arrays Hybrid Beamforming 5 GHz beamforming system 32 element beamforming receiver fast Fourier transform FFT discrete Fourier transform DFT Receiver Chain RF front-end PCB design FPGA A-DFT
339	Design and Development of a Coherent Detection Rayleigh Doppler Lidar System for Use as an Alternative Velocimetry Technique in Wind Tunnels Barnhart, Samuel 20 August 2020 (has links) No description available. Aerospace Engineering Atmospheric Sciences Atmosphere Engineering Optics Technology Coherent Detection Rayleigh Doppler Lidar Doppler Lidar Lidar Velocimetry Wind Tunnels Rayleigh Scattering Mie Scattering Ladar Laser Radar Fourier Transform Fast Fourier Transform FFT DFT Discrete Fourier Transform
340	Pricing Basket of Credit Default Swaps and Collateralised Debt Obligation by Lévy Linearly Correlated, Stochastically Correlated, and Randomly Loaded Factor Copula Models and Evaluated by the Fast and Very Fast Fourier Transform Fadel, Sayed M. January 2010 (has links) In the last decade, a considerable growth has been added to the volume of the credit risk derivatives market. This growth has been followed by the current financial market turbulence. These two periods have outlined how significant and important are the credit derivatives market and its products. Modelling-wise, this growth has parallelised by more complicated and assembled credit derivatives products such as mth to default Credit Default Swaps (CDS), m out of n (CDS) and collateralised debt obligation (CDO). In this thesis, the Lévy process has been proposed to generalise and overcome the Credit Risk derivatives standard pricing model's limitations, i.e. Gaussian Factor Copula Model. One of the most important drawbacks is that it has a lack of tail dependence or, in other words, it needs more skewed correlation. However, by the Lévy Factor Copula Model, the microscopic approach of exploring this factor copula models has been developed and standardised to incorporate an endless number of distribution alternatives those admits the Lévy process. Since the Lévy process could include a variety of processes structural assumptions from pure jumps to continuous stochastic, then those distributions who admit this process could represent asymmetry and fat tails as they could characterise symmetry and normal tails. As a consequence they could capture both high and low events¿ probabilities. Subsequently, other techniques those could enhance the skewness of its correlation and be incorporated within the Lévy Factor Copula Model has been proposed, i.e. the 'Stochastic Correlated Lévy Factor Copula Model' and 'Lévy Random Factor Loading Copula Model'. Then the Lévy process has been applied through a number of proposed Pricing Basket CDS&CDO by Lévy Factor Copula and its skewed versions and evaluated by V-FFT limiting and mixture cases of the Lévy Skew Alpha-Stable distribution and Generalized Hyperbolic distribution. Numerically, the characteristic functions of the mth to default CDS's and (n/m) th to default CDS's number of defaults, the CDO's cumulative loss, and loss given default are evaluated by semi-explicit techniques, i.e. via the DFT's Fast form (FFT) and the proposed Very Fast form (VFFT). This technique through its fast and very fast forms reduce the computational complexity from O(N2) to, respectively, O(N log2 N ) and O(N ). Lévy Factor Copula ; Lévy Random Factor Loading Copula ; Lévy Skew Alpha-Stable ; Generalized Hyperbolic ; Credit Default Swaps; CDS ; Collateralised debt obligation; CDO ; Fast Fourier Transform; FFT ; Very Fast Fourier Transform; VFFT

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