123 research outputs found
Proposal of Part of Information System
Tématem této práce je návrh dílčí části informačního systému podniku. Obsahuje analýzu současného stavu informačního systému a elektronického obchodu, který je s ním propojen. Výsledkem této práce je návrh řešení pro zlepšení funkčnosti a rentability elektronického obchodu, využitím webových propagačních služeb e-marketingu a SEO optimalizace, ale i jiných nástrojů.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.
Fast Computation of Ray-Triangle Intersection
V této práci zkoumáme rychlost 6 metod výpočtu průsečíku paprsku s trojúhelníkem, což je elementární operace při sledování paprsku. Zkoumáme jak jejich implementace softwarové v C++ a SSE, pro výpočty po jednom paprsku i po svazcích 4 paprsků, tak lehkým nástinem jejich implementaci hardwarovou. Metody jsou podrobeny testům s náhodně generovanými i reálnými scénami a z těchto testů nejlépe vyšla pro jednopaprskouvou implementaci metoda Havel Herout (SSE4), pro svazkovou pak metoda Shevtsovova (SSE), přičemž Shevtsovova metoda je z těchto dvou vhodnější pro hardwarovou implementaci.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.
Safety and hygiene of work in the construction industry
Cílem diplomové práce je představit problematiku hygieny a bezpečnosti práce ve stavebnictví. V teoretické části je v první části vysvětlena problematika bezpečnosti práce a ve druhé části problematika hygieny práce. Praktická část práce se zabývá zmapováním situace ve stavebnictví a plánem BOZP.The thesis aims to introduce the issue of health and safety in construction. The issue of safety at work is explained in the first part of the theoretical part. Problems of hygiene are explained in the second part. The practical part deals with the mapping of the situation in the construction industry and occupational health and safety plan.
Efficient Image Tagging
Tato práce se zabývá efektivním tagováním fotografií. Konkrétně se zaměřuje na uspořádání jednotlivých fotografií tak, aby tvořily shluky podle svých vlastností a usnadnily tak výběr podobných fotografií, kterým uživatel může efektivně přiřazovat společné tagy zároveň. K tomuto účelu jsou v práci zkoumány známé techniky zobrazování kolekcí fotografií podle jejich vlastností a s tím související metody redukce dimenzionality. Ze zmiňovaných jsou vybrány a otestovány nejvhodnější možnosti. Tato práce navrhuje nový způsob zobrazování kolekcí fortografií na 2D obrazovce, která kombinuje použití časové osy a seskupování podle podobnosti (Timeline projekce). Pro optimální projekci uskupení v mnohorozměrném prostoru příznakových vektorů na 2-rozměrnou obrazovku je v této práci použita metoda redukce dimenzionality nazvaná t-Distributed Stochastic Neighbour Embedding (t-SNE). Jsou popsány různé modifikace t-SNE a způsoby, jak ji kombinovat s časovou osou, a zvolená modifikace je implementována formou webového rozhraní a kvalitativně vyhodnocena experimentem. Na závěr jsou navrženy možnosti pokračování výzkumu.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.
Analysis of drinks sweetened with stevia extracts
Steviolglykosidy jsou přírodní sladivé látky Stévie sladké (Stevia rebaudiana Bertoni), které příznivě působí na lidské zdraví a jejich relativní sladivost je 300krát vyšší než sladivost sacharózy. Jsou proto využívány ke slazení komerčních výrobků. Vzhledem k jejich potenciálním vlastnostem je výhodné mít vhodnou metodu pro jejich sledování. Vysokoúčinná kapalinová chromatografie (HPLC) je založena na principu rozdělování analytu mezi dvě vzájemně nemísitelné fáze pomocí vysokotlakého čerpadla a vhodně vybrané stacionární fáze kolony. Analyty potom vycházejí z kolony v různých retenčních časech. Tato diplomová práce se zabývá výběrem vhodného HPLC systému pro stanovení hlavních steviolglykosidů a jejich analýzou v komerčních výrobcích. V teoretické části práce je nejprve popsán původ, základní vlastnosti, botanický popis, pěstování, účinky rostliny Stévie sladké na lidské zdraví a její využití v potravinářském průmyslu. Jsou zde i stručně charakterizovány sladivé látky obsažené v rostlině, tzv. steviolglykosidy. Poté jsou uvedeny teoretické základy vysokoúčinné kapalinové chromatografie, instrumentace HPLC a její konkrétní aplikace na steviolglykosidy se základními chromatografickými parametry. Cílem první experimentální části bylo pomocí HPLC zkoumat optimální podmínky pro časově a separačně efektivní chromatografickou analýzu a vybrat tak vhodný chromatografický systém pro stanovení steviolových glykosidů. V druhé experimentální části bylo vybranou chromatografickou metodou porovnáván a stanoven obsah hlavních steviolglykosidů (steviosid, rebaudiosid A) v devíti vybraných produktech komerčně dostupných v České republice (ČR), ve kterých byl výskyt steviosidu nebo rebaudiosidu A buď potvrzen nebo vyvrácen.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.
On 3D flow pattern behind a wall-mounted circular cylinder of finite-length
The wake behind a wall-mounted finite-length circular cylinder of the aspect ratio 2 stuck out of a wall was studied experimentally using stereo PIV technique. The cylinder was mounted normal to a ground plane and it was subjected to a cross-flow with thin boundary layer developed on the wall, the Reynolds number based on inflow velocity and cylinder diameter was 9.7 thousands. The time-averaged velocity and streamwise vorticity fields showed the development of the mean flow structure consisting of the tip vortex pair, the extent of the near-wake recirculation zone with back-flow, the downwash phenomenon and base vortex structures close to the wall
The Importance of Mechanical Transport, Rock Texture, and Mineral Chemistry in Chemical Weathering of Granites: The Melechov Massif, Czech Republic
Data of 41 or more elements in superficial as well as drill-core samples of the peraluminous Lipnice and Melechov granites, located several kilometers apart in northern Moldanubian Batholith, are evaluated. Weathering of both granite types proceeded in virtually identical time and environment, but it shows very different patterns. In the weathered Lipnice granite, Al2O3 slightly increased, loss on ignition (LOI) increased strongly, and contents of all other major elements except for Fe are lower (however, reconcentration of K, Mg, and Ti in secondary phases is possible). In the relatively coarse-grained and more acidic Melechov granite, the depleted major elements are Si, Fe, Ti, Mn, and Mg. Strongly increased Al in half of weathered samples is independent on the moderate increase of LOI and relatively small changes of Na, Ca, K, and P contents. These samples are relatively poor in quartz, which is the result of fossil weathering, mechanical mineral separation, and erosion processes. In the Lipnice granite, however, chemical weathering dominated over mechanical fractionation due to a more compact character of the rock (as well as of biotite and plagioclase). Regarding trace elements, enrichment in Ga and loss of U are the only changes documented in both granite types (in different proportions however). The rare-earth element (REE) fractionation is generally weak, but in the Lipnice granite, two processes are proven: (i) dissolution of apatite which has an M-type lanthanide tetrad effect in the fresh rock and (ii) formation of positive Ce anomaly
On the relationship between social rank during the velvet period and antler parameters in a growing red deer stag
Operating Characteristics of a Timber Trailer with a Hybrid Drive
This paper deals with the design and operational evaluation of a timber tractor-trailer unit with a hybrid trailer drive. The source of electrical energy for the two induction motors driving the front wheels of the tandem trailer axle is a battery, which is recharged by an induction machine operating as a generator during periods of a lower demand for power from the tractor diesel engine. An electric drive was designed for the defined working cycle of the tractor-trailer unit, and its loading characteristics were tested in the laboratory. The parameters measured on the field tests during timber forwarding were battery voltage and power, and the energy balance. Three adjustment levels of the potentiometer controlling the trailer hybrid drive (50, 75 and 100%) were tested at three different forwarding distances of 100, 500 and 1000 m. Additionally, any slippage of the prime mover wheels and trailer was measured. The maximum peak power taken from the battery was ca. 33 kW during the field tests, whilst the drive was able to deliver a peak output of up to 72 kW for 10 s and permanently up to ca. 50 kW. Even in harsh terrain conditions, the electric drive assisted the combustion engine only when the loaded tractor-trailer unit was travelling uphill. The hybrid drive operation was sustainable for the whole working shift, without the need for recharging when the potentiometer was set to 50%. This appropriate setting of the potentiometer controlling the trailer's hybrid drive reduced the slipping of the driven wheels of the tractor-trailer unit whilst travelling uphill.O
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