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Minimizing the effect of interference on wireless network
Doležal, Jan ; Kyselák, Martin (referee) ; Škorpil, Vladislav (advisor)
This thesis is concerned the technology with technologies of transfer through wireless devices. It is about possibilities of optimization of transfer in wireless net, especially of the reduction of interference influence. The first part is about theory and the standards development of wireless technology. There are methods and principles used in wireless technologies. The second part is a practical measuring and testing of an internal wireless net, with the emphasis being on the source of interference influence. Measuring was focused on interference between access points and was not about meteorological influence. It continues with theory and testing of interference of the microwave oven in our wireless net. Then, it is a practical demonstration of interference in an external environment. There are practical examples of interference between different providers’ nets on the same area and solutions to prevent or to cancel this interference. In next part of work the wireless net is parsed and described in a given territory. Here is described the way how to precede the reciprocal interference and eventually how this mutual disturbance suppress. Consequently, our net is optimized for customer growth and for today’s options of newer and more powerful components for wireless transfer. Finally there are two laboratory tasks. The first one is about practical measuring and testing of wireless net’s parameters and the second one is about simulation of wireless networks in the Opnet program.
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Interference modelling for xDSL
Čermák, Josef ; Mišurec, Jiří (referee) ; Zeman, Václav (advisor)
This work is focused on the subject of the interference modelling for xDSL technologies. First, the xDSL technologies are explained. Following is the presentation and description of the different kinds of the xDSL technologies. The next part deals with the basic parameters of metallic cable lines – especially the primary and secondary parameters. Nowadays wider bandwidths are used for the achievement of higher data transmission rates. During a higher frequency signal transmission a more intensive line attenuation appears. To identify the transfer characteristics of the lines while using an xDSL system, mathematic models of transmission lines are applied. That is why these mathematic models are dealt with in the next chapter. At the end of this section the mathematic models are compared using the modular and phase characteristics. The main aim of the work is to describe the different impacts which influence the efficiency of the xDSL systems. First, the causes interfering from the inside of the cable are deeply explained: Near End Crosstalk (NEXT), Far End Crosstalk (FEXT), Additive White Gaussian Noise (AWGN). Following is the explanation of the external interfering impacts: Radio Frequency Interference (RFI) and Impulse Noise. The next goal of this thesis is a design of a workstation for the tests of spectral features and the efficiency of the xDSL systems. The work also presents a designed GUI application and its description. The GUI application is an instrument for the choice or data entry of the final interference. The last chapter describes a realization of a measurement and shows the measured characteristics which were recorded on the ADSL tester and oscilloscope.
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Workstation for optical interferometry
Blecha, Martin ; Honec, Peter (referee) ; Janáková, Ilona (advisor)
This thesis is specialized on composition of workplace for experiments flowing from optical interferometry. Here are described laboratory exercise servant for demonstration basic principles of interferometry. In more details is described method measurement of height profile objects with method white light interferometry.
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Laser Doppler anemometry
Osička, Tomáš ; Lízal, František (referee) ; Jedelský, Jan (advisor)
This bachelor thesis deals with laser Doppler anemometry (LDA). It is a modern, non-intrusive flow measurement technique. The work deals with theoretical principles and components of the method. The experimental part is devoted to setting of the system. Vector plot and profile plot display the measurement results.
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Faux amis in German and in English
KALOVÁ, Michaela
This bachelor thesis deals with the topic "Faux amis in German and in English". This thesis is primarily focused on the semantic faux amis which could pupils in the Czech Republic meet with. The theoretical part defines the basic terminology related to so called false friends. Furthermore, the theoretical part clarifies the formation and classification of faux amis. The practical part contains the gathered semantic faux amis which are classified in the reference levels according to the Common European Framework of Reference for Languages (CEFR). The lists of faux amis of individual levels are in the practical part further analysed.
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Typical grammar errors in text production committed by Czech learners of German-as-a-Foreign-Language - a quantitative and qualitative corpus analysis.
BARTÁKOVÁ, Stanislava
This thesis is divided into two parts a theoretical and a practical one. The main topics of the thesis are the most common grammar mistakes of Czech pupils who learn German as a foreign language. The theoretical part explains terms such as mistake, error or contrastive linguistics, categorizes the errors and presents the reasons for those errors. The main part consists of a corpus analysis of texts written by Czech learners. Their errors are analysed, compared and explained. Graphics show the development of those errors in different learning process stages. Last but not least a questionnaire to explore the teachers' awareness of those errors and their correction will be provided.
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A design of the system for continous evaluation of analytical samples quality in a clinical biochemistry laboratory
SVATOŠOVÁ, Kristýna
The aim of my work is to provide information about the process of evaluating analytic quality of samples. This kind of process is recommended in clinic biochemistry laboratory at present. Serum indexes are measured always, in any required sample test whose result can be influenced by sample quality. It is possible to evaluate the degree of haemolysis, icterus and lipemia in patients´ blood samples by the photometric method. The sample haemolysis is mostly caused by bad technic of blood samples taking or their inappropriate transport so that in the end of this process, in regular intervals there is a possibility to find out the level of results changes in connection with concrete laboratory services users. In theoretical part of my work I describe reasons of sample quality decreasing in vivo that´s something people can´t influence because they originate in a patient´s body and in vitro that are caused by wasteful manipulation. In this part there are also principles of the photometrical methods mostly used. The practical part contains the model example that shows how the analyts can be influenced by artificial adding of interfering substances. I could see increasing of some element concentration after making evaluation: Concentration of K increased by 24%, Fe by 10%, bilirubin by 13% and enzymatic activity ALT by 23%, AST by 179%, GMT by 26% and ALP was reduced by 25% in haemolytic serum. In icteric and lipemic serum there isn´t interference on such high level. Icterus causes decreasing of urea by 17%, creatinine by 27%, enzymatic activity ALT by 10% and activity GMT is increased by 11%. Lipemia decreases concentration of creatinine by 8%, enzymatic activity ALT by 6% and bilirubin is higher by 21%. In the end of my work I introduce statistic conclusion laboratory informatics system that gives laboratory management possibility to find out samples of bad quality in connection with concrete applicants and help to make some reparation.
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