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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.
1

Měření rychlosti šíření ultrazvuku / Measurement of ultrasound speed

Pouč, Petr January 2009 (has links)
The thesis deals with the ultrasonic velocity measurement. The ultrasonic velocity was determined on basis of ultrasonic flight time from a transmitter to a receiver. Three methods how to determine the ultrasonic velocity in medium were proposed. Special algorithms have been created and later on build in the developed program. All the software was developed in Agilent VEE Pro 8.5. The thesis contains a proposal of two experiments tutorials for the department of Biomedical engineering that will be used during experimental lessons. The experiments deal with ultrasonic velocity measurement.
2

Simulace šíření ultrazvuku v kostech / Simulation of Ultrasound Propagation in Bones

Kadlubiak, Kristián January 2017 (has links)
It is estimated that mind-boggling 14.1 million new cases of cancer occurred worldwide in 2012 alone. This number is alarming. Although healthy lifestyle may reduce a risk of developing cancer, there is always some probability that cancer would develop even in an absolutely fit individual. There are two main conditions for successful treatment of cancer. Firstly, early diagnostic is absolutely crucial. Secondly, there is a need for suitable surgical methods for affected tissue removal. Ultrasound has a great potential to be used for both purposes as a non-invasive method. Photoacoustic spectroscopy is imaging method for tumor detection of great properties making the use of ultrasound while High-Intensity Focused Ultrasound (HIFU) is non-invasive surgical method. These methods would be impossible without precise ultrasound propagation simulations. The k-Wave is an open source MATLAB toolbox implementing such simulations. So, why are not these methods already deployed in treatment? Unfortunately, the simulation of ultrasound propagation is a very time consuming task, which makes it ineffective for medical purposes. However, there are a few options how to accelerate these simulations. The use of GPU is a very promising way to accelerate simulation.   The main topic of this thesis is the acceleration of the simulation of soundwaves propagation in bones and hard tissue. The implementation developed as a part of this thesis was benchmarked on various supercomputers including Anselm in Ostrava and Piz Daint in Lugano. The implemented solution provides remarkable acceleration compared to the original MATLAB prototype. It was able to accelerate the simulation around 160 times in the best case. It means that the simulation, which would otherwise last for 6.5 days, can be now computed in one hour. This acceleration was achieved using an NVIDIA Tesla P100 to run the simulation with the domain size of 416x416x416 grid points. The thesis includes performance benchmarks on different GPUs to provide complex image acceleration capabilities of developed implementation and provides discussion about memory usage and numerical accuracy. Thanks to the implemented solution harnessing the power of modern GPUs, doctors and researchers all around the world have a powerful tool in hands.
3

Měření rychlosti šíření ultrazvuku průzvučnou tomografií / Measurement of ultrasound speed using transmission tomography

Pop, Tomáš January 2008 (has links)
The study deals with the image reconstructions using the ultrasound propagation speed measuring and it extends the project of the ultrasound transmission tomography organised in cooperation with the research centre Forschungszentrum Karlsruhe (Germany). There were data processed which had been gained with the 3D ultrasound transmission tomography system (3D USCT). The ultrasound propagation speed was measured using the detection of ultrasound ray travelling time from a transmitter to a receiver. There were three new algorithms developed for the detection of an ultrasound impulse and the software generating suitable testing data. The developed algorithms were consequently tried with these data and, then, included into the existing software. All software was developed within the Matlab programming environment.
4

Lícování ultrasonografických obrazových sekvencí / Registration of Ultrasound Image sequences

Kubica, Roman January 2013 (has links)
The result of this thesis, focused on medical image registration, is an automatic image registration algorithm. It is constructed to be used on real ultrasonography images, created by perfusion imaging. In its introductory part, the thesis deals with registrations methods, next it describes types of optimization principles and single criteria functions served to determine correct image transformation. Based on the theoretical part, there are realized three optimization algorithms using three criterial functions, which served to registration of provided ultrasonography sequences. These algorithms are tested and results are passed on analysis, on its ground are judged its advantages and disadvantages.
5

Vizualizace šíření ultrazvuku v lidském těle / Visualisation of Ultrasound Propagation in Human Body

Klepárník, Petr January 2014 (has links)
This work deals with the 2D and 3D visualization of simulation outputs from the k-Wave toolbox. This toolbox, designed to accurately model the propagation of ultrasound waves in the human body, usually generates immense amounts of output data (up to hundreds of GB). That is why new methods for both the visualization and the effective data representation are necessary to be developed to help users to easily understand the simulation results. This thesis elaborates on the data format, simulation outputs are stored in, with the use of the HDF5 library and looking for the best way to quickly read the simulation data. Finally, the thesis presents the design and the implementation of the console-based application for big simulation data pre-processing and the GUI-based application for interactive visualization of the pre-processed data. The most significant features of these applications are downsampling data, changing the format of storing, viewing 2D sections, planar and volumetric visualization and animation of the simulation process. The proposed implementation allows parts of the simulation domain to be visualised within tens of milliseconds even if the simulation domain comprises GBs of data - This significantly streamlines the work of scientists and clinicians in the field of HIFU.
6

Vliv surovin na vzduchovou neprůzvučnost cihlářského střepu / The Effect of Raw Materials on Sound Insulation of Brick Body

Bosák, Filip January 2017 (has links)
Diploma thesis is concerned with opportunities of increase sound isolution index for bricks. In theoretical part is summary of present knowledge about acoustic properties ceramic body field and theoretical calculations and measuring sound insulation as well as. Practically part is divided on apply and basic research. Under apply research is experiment, that considers impact quantity of raw materials using at brick factory in the Holice on the most significant technological properties of plastic paste and brick body, additionaly with the considering chances of increase sound insulation index. In basic research is experiment, that evaluates impact common use domestic brick´s raw materials on sound insulation. Sound insulation is evaluated indirectly by transsmision rate of ultrasound in a both cases.
7

Implementace ultrazvukových měničů a tkáňových reprezentací do toolboxu k-Wave / Implementation of Ultrasound Transducers and Tissue Models into the k-Wave Toolbox

Hanzl, Martin January 2018 (has links)
Extensions to k-Wave toolbox used for ultrasound modelling are described. Aim of extensions is to reduce time and space complexity by presenting alternative representations of tissues and transducers in simulation. This project clarifies basic principles and features of k-Wave, describes design of new representations and finally describes implementation of the suggested extensions.
8

Akcelerace ultrazvukových simulací pro axisymetrické medium / Acceleration of Axisymetric Ultrasound Simulations

Kukliš, Filip January 2018 (has links)
Simulácia šírenia ultrazvuku prostredníctvom mäkkých biologických tkanív má širokú škálu praktických aplikácií. Patria sem dizajn prevodníkov pre diagnostický a terapeutický ultrazvuk, vývoj nových metód spracovania signálov a zobrazovacích techník, štúdium anomálií ultrazvukových lúčov v heterogénnych médiách, ultrazvuková klasifikácia tkanív, učenie rádiológov používať ultrazvukové zariadenia a interpretáciu ultrazvukových obrazov, modelové vrstvenie medicínskeho obrazu a plánovanie liečby pre ultrazvuk s vysokou intenzitou. Ultrazvuková simulácia však predstavuje výpočtovo zložitý problém, pretože simulačné domény sú veľmi veľké v porovnaní s akustickými vlnovými dĺžkami, ktoré sú predmetom záujmu. Ale ak je problém osovo symetrický, problém môže byť riešený v 2D.To umožňuje spúšťanie simulácií na mriežke s väčším počtom bodov, s menším využitím výpoč- tových zdrojov za kratšiu dobu. Táto práca modeluje a implementuje zrýchlenie vlnovej nelineárnej ultrazvukovej simulácie v axisymetrickom súradnicovom systéme realizovanom v Matlabe pomocou Mex súborov pre diskrétne sínové a kosínové transformácie. Axisymetrická simulácia bola implementovaná v C++ ako open source rozšírenie K-WAVE toolboxu. Kód je optimalizovaný na beh na jednom uzle superpočítaču Salomon (IT4Innovations, Ostrava, Česká republika) s dvoma dvanásť-jadrovými procesormi Intel Xeon E5-2680v3. Na maximalizáciu výpočtovej efektívnosti boli vykonané viaceré optimalizácie kódu. Po prvé, fourierové tramsformácie boli vypočítané pomocou real-to-complex FFT z knižnice FFTW. V porovnaní s complex-to-complex FFT to znížilo čas výpočtu a pamäť spojenú s výpočtom FFT o takmer 50%. Taktiež diskrétne sínové a kosínové transformácie sa počítali pomocou knižnice FFTW, ktoré v Matlab verzii museli byť vyvolané z dynamicky načítaných MEX súborov. Po druhé, aby sa znížilo zaťaženie priepustnosti pamäte, boli všetky operácie počítané jednoduchej presnosti pohyblivej rádovej čiarky. Po tretie, elementárne operá- cie boli paralelizované pomocou OpenMP a potom vektorizované pomocou rozšírení SIMD (SSE). Celkový výpočet C++ verzie je až do 34-násobne rýchlejší a využíva menej ako tretinu pamäte ako Matlab verzia simulácie. Simulácia ktorá by trvala takmer dva dni tak môže byť vypočítaná za jeden a pol hodinu. Toto všetko umožňuje počítať simuláciu na výpočetnej mriežke s veľkosťou 16384 × 8192 bodov v primeranom čase.
9

Diagnostické metody použitelné pro monitorování sušícího procesu cihlářských výrobků / Diagnostic Methods Suitable for Monitoring of Drying Process of Brick Product

Sarvaš, Ondřej January 2019 (has links)
This work deals with the study of diagnostic methods suitable for monitoring of the drying process of brick raw materials. Based on the extensive literature search, several parameters are selected, which are appropriate to monitoring during drying. In addition, a methodology for measuring these selected parameters is proposed. In the experimental part, the use of all described methods is gradually verified on the brick raw material with and without shortening additive (also known as grog). Was carried out: measurement of the surface temperature in the climatic chamber, determination of humidity distribution in the sample, determination of moisture diffusivity, determination of tensile strength, determination of ultrasonic wave velocity and determination of dynamic E-modulus of elasticity. Results of experiments and the gained experiences show, that at least two of the above-mentioned monitoring methods are very appropriate and beneficial – determination of moisture diffusivity and determination of tensile strength. In the work was described in detail the procedure of determination of moisture diffusivity of material. The dependence of moisture diffusivity on the moisture content of the dried material, has been described. Also, differences between raw material with grog and without grog has been described. As part of the practical verification of the experiment designed to determine the tensile strength at different humidity levels of test samples. A new shape of the test specimens and a new device were designed to allow them to be attached to a hydraulic press. The results of this work show that the tensile strength of the ceramic green bodies is primarily dependent on the moisture content of the material. The type of raw material almost does not affect the tensile strength.
10

Ultrazvukové měření velkoformátových obkladů / Ultrasonic measurement of large format tiles

Čaněk, Michal January 2021 (has links)
The diploma thesis deals with influence of the used adhesive to large format tiles properties after installation. Properties on large format tiles were monitored by ultrasonic pulse velocity method. Hydraulic setting adhesives were tested in second part. Strength and modulus of elasticity were tested. The development of shrinkage over time was also monitored. The results were summarized in tabular and graphical form and were examined by simple statistical analysis to determine resulting conclusions.

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