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Fast Computation of Ray-Triangle Intersection
Procházka, Václav ; Havel, Jiří (referee) ; Herout, Adam (advisor)
In this thesis we try to examine speed of 6 methods for ray-triangle intersection computation, which is elementary operation performed in raytracing. We examine their software implementations in C++ and SSE, for both single-ray and 4-ray packet implementation, as well as their hypothetical hardware implementation. Methods are tested with both randomly generated and real scenes and best results were measured for method Havel Herout (SSE4) among single-ray implementations and Shevtsov's method (SSE) among ray-packet implementations, where Shevtsov's method is of those two more suitable for hardware implementation.
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Proposal of Part of Information System
Procházka, Václav ; Kolesa, Jaroslav (referee) ; Luhan, Jan (advisor)
The theme of this work is the design component of an information system of company. It includes analysis of the current state of information systém a e-shop which is connected to. The result of this thesis is proposal of a design which will lead to enhancement of e-shop functions and it‘s profitability, by using e-marketing web propagation services and SEO optimalization, and even other tools.
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Analysis of drinks sweetened with stevia extracts
Procházka, Václav ; Hrstka, Miroslav (referee) ; Vespalcová, Milena (advisor)
The steviolglycosides are the natural, sweet substances from Stevia rebaudiana Bertoni. It affect human health positively and its sweetness is 300x stronger than the sweetness of sucrose. That's why it's used to sweetening the commercial products. Because of its potential properties it's good to have an appropriate method to isolate it. High performance liquid chromatography ( HPLC) is based on the separation of analyte between two immiscible phases with high pressure pump and appropriately chosen stationary phase in the column. Than the analytes come out from the column in different retention times. This master´s thesis follows up selection of the best HPLC system for isolation of the main steviolglycosides and its analysis in commercial products. In the theoretical part of the thesis is described the origin, basic characteristics, botanical description, cultivation and affect to the human health of Stevia rebaudiana Bertoni and its use in food industry. There are also concisely characterized the sweet substances contained in the plant, so called steviolglycosides. Than there are given the theoretical basics of high performance liquid chromatography, HPLC instrumentation and its specific applications at sleviolglycosides with the basic chromatographic parameters. The object of the first experimental part was to research the optimum conditions for time and separation effective chromatographic analysis and select the best chromatographic system for isolation of steviolglycosides. In the second experimental part, I have compared and defined the main steviolglycosides (stevioside, rebaudioside A) in nine selected products, commercially available in Czech republic, with the best chromatographic method. In these products was the contain of the stevioside or rebaudioside A confirmed or refused.
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Efficient Image Tagging
Procházka, Václav ; Zemčík, Pavel (referee) ; Hradiš, Michal (advisor)
This thesis investigates efficient manual image tagging approaches. It specifically focuses on organising images into clusters depending on their content, and thus on simplifying the selection of similar photos. Such selections may be efficiently tagged with common tags. The thesis investigates known techniques for visualisation of image collections according to the image content, together with dimensionality reduction methods. The most suitable methods are considered and evaluated. The thesis proposes a novel method for presenting image collections on 2D displays which combines a timeline with similarity grouping (Timeline projection). This method utilizes t-Distributed Stochastic Neighbour Embedding (t-SNE) for otpimally projecting groupings in high dimensional feature spaces onto the low-dimensional screen. Various modifications of t-SNE and ways to combine it with the timeline are discussed and chosen combination is implemented as a web interface and is qualitatively evaluated in a user study. Possible directions of further research on the subject are suggested.
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Phosphates and accessory oxides in selected granitoids and paragneisses of the Moldanubian area in southeastern and southern Bohemia
Procházka, Václav ; Matějka, Dobroslav (advisor) ; Štemprok, Miroslav (referee) ; Petrík, Igor (referee)
The thesis deals with granites and paragneisses prevalently in the area of northern Moldanubian Batholith (especially the Melechov massif). The main object are accessory minerals, also some information replenishing the knowledge about geochemistry and petrography of studied rocks has been obtained. The research has been focused mainly on phosphates and Fe-Ti oxides. Fluorapatite (only "apatite" in the following text) is common in all granitoids as well as paragneisses. In metamorphic rocks and in little fractionated granites (the Lipnice and Pavlov types), apatite is very homogeneous and only exceptionally corroded. In more fractionated granites, complicated evolution of apatite has been documented with the usage of cathodoluminescence. The cathodoluminescence is influenced mainly with admixtures of Fe, Mn, Y and REE, as documented in literature. In addition, irradiation (mainly from monazite inclusions) darkens the luminescence, and the influence of uneven surface is also significant. The contents of Na, Fe, Mn, Y and REE are higher in the interior of unaltered crystals. Trace-elemnt determination (LA-ICP-MS) in apatite in granites of Melechov massif also shows that the unaltered primary apatite has also higher U and lower Sr content, deeper negative Eu-anomaly, and more pronounced M-type tetrad...
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Utilization of CTA and CTP in Middle Cerebral Artery Stroke
Cimflová, Petra ; Krajina, Antonín (advisor) ; Neuwirth, Jiří (referee) ; Procházka, Václav (referee)
Introduction: Diagnostic imaging has a crucial role in the diagnosis and therapeutic management of acute ischemic stroke (AIS). The main aim of this thesis was to further evaluate the utilization of CTA and CT perfusion (CTP) in the diagnosis and treatment decision in patients with AIS caused by the occlusion of the middle cerebral artery. Methods: Study in Chapter 2 evaluated the automatically derived CT perfusion lesion volumes (PLV) and hypoperfusion intensity ratio (HIR) with collateral score using multiphase CTA (mCTA) (Kruskal-Wallis, Wilcoxon rank-sum test and Spearman's rho correlation coefficients were calculated). In study in Chapter 3, the assessment of ischemic changes by expert reading and available automated software for non-contrast CT and CTP was compared (the sensitivity, specificity, positive and negative predictive value were calculated). In Chapter 4, the performance of StrokeSENS software tool in detection of anterior large vessel occlusions (LVO) was tested (receiver operator characteristics analysis). Study in Chapter 5 investigated whether prediction of clinical outcome and final infarct volume can be improved by collateral status assessment on time-variant color-coded mCTA (multivariable logistic regression). The aims in Chapter 6 were to determine if mCTA-derived tissue...
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Endovascular Treatment of Arteriovenous Fistula for Dialysis
Vorčák, Martin ; Krajina, Antonín (advisor) ; Peregrin, Jan (referee) ; Procházka, Václav (referee)
Endovascular treatment of arteriovenous fistula for dialysis Aim: Aim of presented retrospective study was to evaluate the primary patency of angioplasty using a drug eluting balloon (DEB) and conventional balloon (PTA) in dysfunctional dialysis fistula. Methods: 58 adult patients treated for fistula dysfunction in the period from 2015 to 2018 were enrolled based on following criteria - matured native fistula with stenosis above 50 % compared to the adjacent healthy vein. Patients with restenosis, swing point, cephalic arch, and central vein stenosis, and multiple distant stenoses were ruled out. Patients were divided into two groups according to received treatment - DEB and PTA. Primary patency of angioplasty was defined as the function of dialysis without the need for clinically driven endovascular or surgical intervention on culprit lesion during follow-up. Secondary, dialysis access patency, 12-month assisted patency, technical, clinical success, complication rate, and mortality among treated groups were evaluated. Results: Primary patency at 6 and 12 months follow up was evaluated in 25 patients in the DEB and 25 patients in the PTA group. Primary lesion and access patency were in DEB vs. PTA: 96 % vs. 76 % (p = 0,1) and 96 % vs. 72 % (p = 0,049) at 6 months, 80 % vs. 56 % (p = 0,13), 80 % vs....
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Trace elements in carbonates of the Czech Creataceous Basin
Štěpánková, Anna ; Procházka, Václav (advisor) ; Štaffen, Zdeněk (referee)
The presented work is focused on research of distribution of trace elements in carbonate sediments and fossils in the Bohemian Cretaceous Basin. To obtain maximum information about the composition of the primary carbonate and its crystallization environment, the trace elements were analyzed mainly in fractions soluble in diluted acid. Another objective is the comparison of trace-element abundance in the soluble fraction and in the residue (or in the total mass of the samples). The results show that there are no systematic differences in the chemical composition of the original carbonate between various regions and stratigraphic positions (Cenomanian - upper Turonian). Elements like Sr, Mg and Mn in carbonate were affected by diagenesis, but contents and mutual ratios of the rare earth elements in all carbonates are similar and are characterized by negative cerium anomaly. The Ce-anomaly could be attenuated by elevated content of clastic matter, and in the soluble portions ocassionally via contamination by secondary phosphate. On the other hand, soluble fractions of limonite-rich and calcite-poor sandstones have positive cerium anomaly, which is the effect of Ce-sorbtion on limonite.
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