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Creating a computational model of the human vocal tract
Freiwald, Michal ; Hájek, Petr (referee) ; Švancara, Pavel (advisor)
The research part of this bachelor’s thesis consists of a brief introduction to the human respiratory system and its subsidiary vocal subsystem along with a summary of basic phonation theories, voice disorders and published computational models of the human vocal tract. The experimental part engages in the making of the computational model itself, set to pronunciation of the vowel /a:/ in a woman vocal tract, on which, using finite element method, some of the basic acoustic analyses are performed, such as modal analysis or harmonic analysis. Calculated formants correspond with the values published in literature. Several different methods were analyzed while computing harmonic response. The most complex and the most time-consuming method, using infinite elements, also proved to be the most precise one. Thesis gives a decent comparison of the precision and complexity between the used methods.
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Creating a computational model of the human vocal tract
Freiwald, Michal ; Hájek, Petr (referee) ; Švancara, Pavel (advisor)
The research part of this bachelor’s thesis consists of a brief introduction to the human respiratory system and its subsidiary vocal subsystem along with a summary of basic phonation theories, voice disorders and published computational models of the human vocal tract. The experimental part engages in the making of the computational model itself, set to pronunciation of the vowel /a:/ in a woman vocal tract, on which, using finite element method, some of the basic acoustic analyses are performed, such as modal analysis or harmonic analysis. Calculated formants correspond with the values published in literature. Several different methods were analyzed while computing harmonic response. The most complex and the most time-consuming method, using infinite elements, also proved to be the most precise one. Thesis gives a decent comparison of the precision and complexity between the used methods.
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Further developements in radiometric method for measurement of slurry density distribution in pipe flow
Krupička, Jan ; Matoušek, Václav ; Pěník, Vojtěch
Laboratory test loop for slurry pipe experiments at the Institute of Hydrodynamics is equipped with two prototypes of radiometric devices which are in permanent evolution as well as the radiometric method of measurement and data processing. Effect of usage of collimated gamma-ray source on the spatial resolution of the radiometric method is studied in this article. Up to now, four differend versions of image reconstruction methods were used to evaluate concentration distribution in a pipe cross-section. Comparison of these methods is presented based on experimental data.
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Ionizing radiation doses of the radiology assistants in the CT and PET/CT wards
MAZLOVÁ, Lenka
Hybrid methods, such as PET/CT, operating with the ionizing radiation, are being used more and more frequently, the number of wards working with this device increases in the Czech Republic. Just PET/CT belongs to the most modern imaging methods among them. In my thesis I compare the radiation doses to which the radiology assistants in the nuclear medicine ward and radiodiagnostics ward are exposed to. The part of the assessment is also the comparison of the radiation protection in the mentioned wards. From methodology point of view, I compared two wards, the hospital ``Na Homolce{\crqq}, where is situated the PET centre with the hybrid PET/CT device, and ``Úrazová nemocnice{\crqq}, equipped with the CT device. With the approval of the employees of the individual wards the data on the quantity of the examinations were processed for the period from 1. 1. 2008 to 30. 9. 2009. Data on the radiation doses were processed by the National Service of Personal Dosimetry in Prague. The number of staff in the individual wards varied during the monitored period, in common there were 13 people in each ward. Radiation load doses for each person were regularly registered during the monitored period. Dosimeters were used for the registration. The nuclear medicine ward uses personal and fingertip dosimeters. These are evaluated each month. On the contrary, the diagnostics ward - CT ward uses only personal dosimeters, evaluated once in three months. The values are presented in the tables. Comparing the personal dosimetry of the PET centre staff and the computer tomography staff, we come to the following results: Monitored period 1 and {$^3\!/\!_4$} year. Annual doses of the ionizing radiation per the person involved in the computer tomography can reach maximally 0,4mSv in the personal dosimetry. Doses per the representative of the PET centre equal to 2.88mSv per year for the personal dosimeters. The results confirmed the hypothesis assuming that the radiology assistants in the nuclear medicine ward are exposed to higher radiation load in comparison to the radiodiagnostics ward working with the CT device. The results comply with the limits for the radiation staff as stipulated in the notice 307/2002 Coll.
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