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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.
51

Využití spektrální metody při simulacích modelu fázového pole pro martenzitické transformace / Application of the spectral method to the simulation of the phase-field model for martensitic transformation

Sejková, Klára January 2020 (has links)
For some alloys martensitic transformation is responsible for the so-called shape memory effect and pseudoelasticity. These properties are used in a wide range of industry applications. Each of these materials is transformed to the shape it was manufactured in when heated to its critical temperature (austenite phase) no matter how seriously it was deformed at lower temperatures (martensite phase). Looking at the microstructure, one can observe significant change of crystalographic lattice depending on temperature and deformation. This the- sis focuses on modelling the evolution of microstructure during deformation for materials in the martensite phase. In this case, the creation of multiple variants of martensite is observed, divided by interfaces where a part of energy is stored. This behaviour can be described by the phase-field model. The numerical im- plementation of this model using the standard finite element method requires large computational costs. The aim of this thesis is to implement this model in MATLAB using a spectral method based on the fast Fourier transform, which is suitable for solving problems on a periodic domain. It is interesting to com- pare the computation using spectral method on a conventional PC with the computation written in FEniCS computed on a cluster. However, the...
52

Radarový signálový procesor v FPGA / Radar Signal Processor in FPGA

Přívara, Jan January 2017 (has links)
This work describes design and implementation of radar processor in FPGA. The theoretical part is focused on Doppler radar, principles of radar signal processing methods and target platform Xilinx Zynq. The next part describes design of radar processor including its individual components and the solution is implemented. FPGA components are written in VHDL language. In the end, the implementation is evaluated and possible continuation of this work is stated.
53

Implementace výpočtu FFT v obvodech FPGA a ASIC / FFT implementation in FPGA and ASIC

Dvořák, Vojtěch January 2013 (has links)
The aim of this thesis is to design the implementation of fast Fourier transform algorithm, which can be used in FPGA or ASIC circuits. Implementation will be done in Matlab and then this form of implementation will be used as a reference model for implementation of fast Fourier transform algorithm in VHDL. To verify the correctness ofdesign verification enviroment will be created and verification process wil be done. Program that will generate source code for various parameters of the module performing a fast Fourier transform will be created in the last part of this thesis.
54

Návrh nové metody pro stereovidění / Design of a New Method for Stereovision

Kopečný, Josef January 2008 (has links)
This thesis covers with the problems of photogrammetry. It describes the instruments, theoretical background and procedures of acquiring, preprocessing, segmentation of input images and of the depth map calculating. The main content of this thesis is the description of the new method of stereovision. Its algorithm, implementation and evaluation of experiments. The covered method belongs to correlation based methods. The main emphasis lies in the segmentation, which supports the depth map calculation.
55

Frekvenční analýza EMG dat u silových trojbojařů / Spectral Analysis of Electromyography Data of Power Lifters

Kofránková, Vlasta January 2016 (has links)
Title: Spectral Analysis of Electromyography Data of Power Lifters Objectives: The aim of this thesis is a description of muscle activity and its measu- rement using electromyography (EMG), description of parameters of EMG signal and their relationship to neuromuscular physiology. The aim of the practical part is an implementation of spectral analysis of EMG data of power lifters when performing 4 series of 5 split-squats carrying loading in one hand. Methods: The spectral analysis of EMG data of 35 athletes is presented. The athletes performed 4 series of 5 split-squats with one sided loading. The loading was 25% and 50% of their body mass and the carrying position was homolateral and contralateral to stance leg. Muscles chosen for measurement were vastus medialis obliquus, vastus lateralis obliquus, gluteus medius and biceps femoris of both sides. The implementation of digital signal proces- sing algorithm was done using Matlab and its Signal Processing Toolbox. The spectral analysis was implemented using discrete Fourier transform with sliding 256-sample window size and 32-sample window increment. The resulting spectrogram was divided into parts based on smoothed EMG. Median frequency for each split-squat was calculated. For the statistical processing we used median frequency differencies...
56

Systém automatického ladění pro sedmistrunné kytary / The automatic self tuning system for seven-string guitars

Jeřábek, Vojtěch January 2017 (has links)
The thesis describes a realization of the automatic self tuning system for sevenstring guitars. There are comparisons of commercial and uncommercial solutions for six-string guitars. There is also evaluation of useful parts for seven-string guitars. Thesis contains a description of a requirements for individual parts and a control software with respect on real guitar properties and used computing algorithm. In the second part of thesis, there is a description of final system design and its realisation including the control software. This is also related with testing of the entire system.
57

Využití akustické emise při sledování hydraulických strojů / Monitoring of hydraulic machines using acoustic emissions

Závorka, Dalibor January 2017 (has links)
The goal of this diploma thesis is to clarify possibilities of usage of acoustic emission as a hydraulic machinery diagnostics tool. Especially for exposing presence of ruptures or cracks in the parts of machine, assuming changes in acoustic exposure of the part during operation. This clarification is based on series of simple measured experiments, which consist of monitoring the bolt placed in fluid stream inside of a pipe. This bolt was preloaded against inner wall of pipe by appropriate tightening torque. This preload is supposed to simulate effects of the size of rupture. High preload simulates small rupture or none in object and respectively small preload is supposed to simulate big rupture. A group of pressure sensors and accelerometers measures experiments and their evaluations are processed by script created in software MATLAB. Outputs of this script are charts with effective values of respective sensors from the entire record split into individual frequency spectrums. These charts compare spectrums of each configuration to judge effects of parameters changes.
58

Citlivostní analýza metody tlak-čas na nepřesnosti měření / Sensitivity analysis of pressure-time method on measurement uncertainty

Červinková, Kateřina January 2019 (has links)
The pressure-time method is one of two methods of measuring the flow rate on large hydraulic structures applicable to IEC 60041, which is based on the temporal integration of the measured pressure difference and the formation of a water hammer in a closed pipe. The aim of this master thesis is to perform a literature review of this method and to evaluate the flow rate of the measured data. Furthermore, the thesis deals with determination of the sensitivity of the evaluated flow rate to the weights of individual pressure sensors and to numerical modifying of the measured pressures. The first part is made using MS Excel. The flow rate is always evaluates with only one pressure sensor and it is compared with the original flow rate. There is research, how absence of the sensor has an impact on the evaluated flow rate. In the second part of the determination of the sensitivity of the evaluated flow rate, various encroachment (signal smoothing, noise, time delay, frequency band removal) are performed of measured pressure signal in Matlab. Various surrounding influences or sensors failures are simulated.
59

Vyhodnocení variability rychlosti pulzové vlny / Analysis of pulse wave velocity variability

Benešová, Lenka January 2019 (has links)
This diploma thesis deals with the variability of pulse wave velocity. It studies the variability of cardiovascular signals. It presents the research of measurement of pulse wave velocity and its analysis in physiology and pathological physiology. Applies spectral analysis in Matlab to a data set. It evaluates and reviews the results of this analysis
60

Porovnání úspěšnosti vícekanálových metod separace řečových signálů / Comparison of success rate of multi-channel methods of speech signal separation

Přikryl, Petr January 2008 (has links)
The separation of independent sources from mixed observed data is a fundamental problem in many practical situations. A typical example is speech recordings made in an acoustic environment in the presence of background noise or other speakers. Problems of signal separation are explored by a group of methods called Blind Source Separation. Blind Source Separation (BSS) consists on estimating a set of N unknown sources from P observations resulting from the mixture of these sources and unknown background. Some existing solutions for instantaneous mixtures are reviewed and in Matlab implemented , i.e Independent Componnent Analysis (ICA) and Time-Frequency Analysis (TF). The acoustic signals recorded in real environment are not instantaneous, but convolutive mixtures. In this case, an ICA algorithm for separation of convolutive mixtures in frequency domain is introduced and in Matlab implemented. This diploma thesis examines the useability and comparisn of proposed separation algorithms.

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