802.11n and 802.11e standards for wireless networks

Tato bakalářská práce je zaměřena na problematiku standardů bezdrátových sítí. Teoreticky popisuje nejznámější standardy skupiny standardů IEEE 802.11, jejich funkce a chování. Dále práce podrobněji rozebírá nový standard 802.11n a specifikaci standardu 802.11e, WMM. Práce obsahuje zprávu o praktických testech standardů 802.11n a WMM, které slouží pro objektivní posouzení schopností těchto standardů.This bachelor thesis is focused on broad issue of wireless network standards. It theoretically describes the most famous standards of IEEE 802.11 group, functions and behavior. It also closely analyzes the new standard 802.11n and the specification of 802.11e, WMM. The paper includes a report of practical tests of standards 802.11n and WMM, which serves for an objective appreciation of capabilities of these norms.

NEUTRONIC ANALYSIS OF THE CANDIDATE MULTI-LAYER CLADDING MATERIALS WITH ENHANCED ACCIDENT TOLERANCE FOR WWER REACTORS

The paper summarizes preliminary results of neutronic analysis of candidate ATF cladding materials that are under development at the CTU in Prague. To evaluate basic neutronics-related characteristics the Serpent code was used which is a Monte-Carlo based simulation tool. A model of WWER fuel was developed and basic neutronic analysis performed. All coating materials entail certain reactivity penalty compared to reference uncoated cladding that was quantified. The coating of cladding affects also other neutron-physical parameters of cores that modify the performance of the WWER reactors that are discussed

Measurement and Numerical Modeling of Mechanical Properties of Polyurethane Foams

This chapter focuses on determination of mechanical properties of polyurethane foams applied in automotive industry and medicine. These materials have strong nonlinear viscoelastic behavior that is time dependent. A comprehensive description of their characteristics is very tough and difficult. Mechanical properties can to some extent be studied using mathematical models that need to be verified with measurements. This chapter describes selected mathematical relationships, rheological models, and also numerical simulations that can approximately describe mechanical properties. Mechanical properties of polyurethane foam are influenced by internal and external structure, shape and size of the cells, filling volume, and properties of the used polymer. Studied mechanical properties are contact pressures, stress distribution, and the dependence of stress on the strain rate

Is it sufficient to assess cost behavior merely by volume of production? Cost behavior research results from Czech Republic

This paper presents results from quantitative research performed as part of a project on cost variability and cost management systems. The main goal was to analyze principal findings that arise through seeking to determine levels of cost management, as well as from comprehending various types of cost behavior affecting manufacturing enterprises in the Czech Republic. The first part summarizes contemporary theories on approaches to cost management that place emphasis on overhead cost management and general and asymmetric cost behavior. The second section deals with the procedure and methodology of the research conducted. Moreover, presentation is given of surveyed questions and hypotheses that form the basis for analysis of particular areas within cost management. The subsequent part presents actual results from research verified through statistically inspecting dependence relations. It was found that the share of overheads was still relatively high, although it had decreased in comparison with figures from previous surveys. Furthermore, there was evidence of significant association between the size of a company and the attention paid to a broadened perception of cost behavior and to monitoring the same. In addition, it was confirmed that senior executives were not aware of issues regarding asymmetric cost behavior or the influence of factors beyond production capacity. It was proven that a dependence exists between the prevalent type of production and complications arising in research, e.g. utilization of the ABC method or monitoring semi-fixed and semi-variable costs. These findings are discussed in the final part of the paper

FEM Analysis of Mechanical and Structural Properties of Long Fiber-Reinforced Composites

This chapter deals with studies of the mechanical properties of samples from long fiber-reinforced composite structures that would contribute to the optimization of the developed constructions made of them. First, the basic issues of composite structures reinforced with long fibers (carbon or glass) and generally of composites with the specification of parameters that would lead to the optimization of mechanical properties with respect to the theoretical strength are presented. Further, the possibilities and methods of measurements of composite reinforced with carbon and glass fibers are described. This is followed by the introduction of analytical models for the description of the transversal isotropic composite, where these mathematical relations allow the determination of unknown elastic constants and they are also important for the verification of numerical models. Finally, it is comprehensively outlined the problems of creating a numerical model of advanced composite fibrous structure for determining the mechanical properties, both through the description of the continuum, and complex numerical model with a structural configuration enabling approach to allow closer interaction among fibers and matrix. Compared to the averaged values obtained from experimental samples, numerical simulations show a similar trend of stress on strain, with results obtained from simulations

Contemporary czech film criticism as endangered genre

Bakalářská diplomová práce nazvaná "Současná česká filmová kritika jako ohrožený žánr" se snaží zhodnotit současnou podobu filmové kritiky v českých tištěných periodikách, které se jí soustavně věnují, zmapovat významné internetové alternativy filmové kritiky (kritické i fanouškovské blogy), popsat způsoby jejich koexistence a vzájemného ovlivňování. První část práce je věnována průzkumu toho, co se rozumí označením "kritika", jaký je její účel, jaké funkce má plnit, jak se dělí a jak přistupovat k jejímu psaní. Druhá část se zabývá filmovou kritikou z hlediska její dějinné pozice v době všeobecného rozšíření internetu, kdy se vedle žurnalistické a filmově-vědní větve filmové kritiky objevila nová větev, již tvoří filmoví nadšenci, píšící na internet. Třetí část zkoumá současné postavení a tendence filmové kritiky v českých tištěných médiích, srovnávacímu rozboru jsou pro ilustraci podrobeny články hodnotící aktuální distribuční filmy na stránkách čtyř konkrétních periodik - jednoho celostátního deníku a tří specializovaných filmových časopisů.This thesis called "Contemporary Czech Film Criticism as an Endangered Genre" is supposed to assess the contemporary image of the film criticism in the Czech printed serials, that apply to it steadily, to chart significant Internet alternatives of the film criticism (critic and fan blogs), to describe some ways of their coexistence and mutual influences. First part is devoted to a research of the meaning of the term "criticism", what its intention is, which functions it should fulfill, which kinds of it could be distinguished and how it should be written. The second part is focused on the film criticism in the light of its historic position in the age of wide extension of the Internet, when a new branch of the film criticism has appeared apart from the journalistic one and the one of the film studies - this branch is formed by movie fans, who publish on the Internet. The third part examines the contemporary position and tendencies of the film criticism in the Czech printed media, the subject of an illustrative analyses are the articles that rank the actual films in cinemas in four concrete printed serials - one nationwide daily and three specialized film magazines.Department of JournalismKatedra žurnalistikyFaculty of Social SciencesFakulta sociálních vě

Innovation of fibrous granular zeolite carrier using single purpose machine

71 stran :ilustrace, výkresy +volná příloha + 1 CD-ROMPráce se zabývá konstrukčním řešením inovovaného zařízení pro výrobu obvazového materiálu obsahujícího částice granulárního zeolitu. První část práce se zabývá možnými řešeními daného problému, přičemž je využito vepolové analýzy a metody TRIZ. Na základě získaných informací je proveden návrh vlastních řešení ve formě konceptů a výběr nejvhodnější varianty pomocí rozhodovacích tabulek s váhovými kritérii. Vítězný koncept je vytvořen v podobě 3D modelu. Navržený model je detailně popsán jak z pohledu samotného konstrukčního řešení tak i souladu návrhu s metodami DFX. Na základě zjištění plynoucích z FMEA-K a modálních analýz konstrukce byly navrženy optimalizace konstrukčního řešení. Pro optimalizovaný model je vytvořena kompletní výkresová dokumentace zařízení, zhodnoceny jsou technické parametry a nákladové parametry zařízení včetně kalkulace konstrukčních materiálů, pohonů a dalších komponent nutných pro zhotovení zařízení. Posouzen je taktéž přínos inovovaného zařízení. Výsledkem diplomové práce je konstrukční návrh inovované zařízení určené pro výrobu vlákenného nosiče granulárního zeolitu