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Step-down converter with variable output voltage in range from 20 to 100 V
Pazourek, Petr ; Šmirg, Ondřej (referee) ; Hanák, Pavel (advisor)
This master's thesis describes the design and the implementation of a step-down converter with variable output voltage for laboratory purposes. In the introduction the basic functions of switching power supplies are shown, flyback, forward and push-pull converters are described, followed by some integrated circuits for power management of converters. The second chapter discusses in detail the design of requested switched power supply, including the calculation of the electronic parts and design of the storage inductor. Following are described some observations of building this power supply, including the output characteristics. In conclusion, the obtained results are assessed, including proposals to improve whole design.
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SW model of PLC controlled crossing
Simon, Jakub ; Bílek, Michal (referee) ; Zezulka, František (advisor)
The objective of this thesis is to create a software model to control various types of crossroads using programmable logic controller. The control system is created on Siemens PLC SIMATIC S7-300. The programmes of system are written in different programming languages such as GRAPH, STL, LAD. The visualisation is also created to control by using of SCADA system InTouch from the company Wonderware. The visualisation comunicates with the PLC using a DAServer. The visualisation has both, input and output elements, so it is not intended for supervising the run of the control system only, but also for simple user‘s control, using a graphical user interface. It is possible to control the start and stop events of the system, and to switch between different crossroad's control modes and also to trigger the pedestrian's button.
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Remote control of targets
Tkáč, Stanislav ; Frýza, Tomáš (referee) ; Jakubová, Ivana (advisor)
The task of this work is to make a functional device, that is intended to close only one of several (38 to 55) of electromagnetic valves. Which valve is going to be switched is elected either of the push-button keypad, or from a PC via RS 232. Equipment must be made using one or more PIC processors.
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Various approaches to visualization of 2D and 3D objects in computer graphics
Polášek, Radek ; Kotásek, Miroslav (referee) ; Langerová, Petra (advisor)
Cílem této semestrální práce je rozšířit povědomí lidí v okruhu procesů, které jsou využívány moderními počítačovými programy, k vizualizaci 2D a 3D objektů. Postupně projdeme některé nejzákladnější definice a koncepty funkcí a jejich parametrů, které poté v následujících kapitolách této práce využijeme k vysvětlení pokročilejších procesů, které umožňují grafickou reprezentaci těchto funkcí v souřadnicových systémech. Poslední kapitola se pak zaobírá přímo příklady z konkrétního počítačového softwaru a tím, na co by uživatel měl brát zřetel aby dosáhl úspěšné grafické reprezentace funkcí.
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Transfer between verbal and algebraic descriptions. Pupils' strategies and problems
Novotná, Anežka ; Vondrová, Naďa (advisor) ; Roubíček, Filip (referee)
The aim of this thesis is to gain insight into the problems that pupils have when switching between verbal and algebraic expressions, through the analysis of their problem-solving processes. The work is divided into theoretical and experimental parts. The theoretical part of the paper contains three sections. The first describes the analysis of three selected Czech textbooks series for primary schools in terms of teaching the concept of variables and algebraic expressions. The next section deals with international comparative research TIMSS and the success of Czech pupils of year 8 in algebra. In the third section, results of international research concerning the issue of transition between verbal and algebraic expressions are described. The main part of the work is the experimental part, it aims to describe the difficulties encountered by pupils in algebra and to identify their likely sources. The basis for the own research was a set of 9 problems based on released TIMSS problems. The target group of pupils was year 9 of primary school, with whom the investigation was carried out via think-aloud interviews. First, a pilot study was conducted on a sample of 3 pupils, during which a set of test problems was checked. The main study involved 8 pupils. The think-aloud interviews were recorded and later...
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Pupils' problems when solving problems requiring substitution
Schánělec, Jan ; Vondrová, Naďa (advisor) ; Novotná, Jarmila (referee)
Title: Pupils' problems when solving problems requiring substitution Abstract: The work focuses on 8th and 9th graders' difficulties and mistakes when solving problems using substitution. The theoretical part defines the used concepts and discusses selected results from international comparative studies and studies focusing on substitution. The main goal of the work is to identify pupils' difficulties and mistakes they make when solving problems using substitution and to discover their origin or cause. To achieve this goal the empirical part begins with an analysis of three sets of textbooks used by pupils involved in this research study. This is followed by a description of conducting and subsequent analysis of fifteen clinical interviews on problems with substitution with 14 to 15 year old pupils (9th graders from elementary schools and 3rd graders from lower secondary grammar schools). In the final part the most common mistakes are summarised and relations to their possible origin in the set of textbooks used looked for. The conclusion is that pupils do not have problems with substitution as such when substituting natural numbers into first power variables. However, this does not hold for substitution of variable in the second power. Pupils have problems when substituting for a variable with a negative...
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How pupils solve generalising tasks
Nováková, Aneta ; Vondrová, Naďa (advisor) ; Novotná, Jarmila (referee)
The diploma thesis focuses on generalization tasks. Its aim is to gain insight into the solving strategies that pupils use and to determine whether the chosen approach depends on the acquired knowledge about the variable. The work is divided into theoretical and research part. The theoretical chapter contains three parts. The first is devoted to letters in mathematics and generalization problems as one of the ways of introducing a variable. The next part presents the results of Czech pupils in the international comparative research TIMSS in the problems on generalisation. The last part is devoted to curricular documents and the analysis of selected textbooks in terms of the occurrence of generalization problems. More attention was devoted to the only textbook series which includes generalization tasks. The research part is the core of the work. Its aim is to describe the solution strategies of selected pupils. Four tasks were the basis of the research. They were selected by the author from various research sources and graded according to their difficulty. Pupils who had already encountered the term variable were the target group as well as pupils for whom it was a new term. Eight pupils participated in the research. They were interviewed about their solutions of the assigned tasks. Next, the...
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Various approaches to visualization of 2D and 3D objects in computer graphics
Polášek, Radek ; Kotásek, Miroslav (referee) ; Langerová, Petra (advisor)
Cílem této semestrální práce je rozšířit povědomí lidí v okruhu procesů, které jsou využívány moderními počítačovými programy, k vizualizaci 2D a 3D objektů. Postupně projdeme některé nejzákladnější definice a koncepty funkcí a jejich parametrů, které poté v následujících kapitolách této práce využijeme k vysvětlení pokročilejších procesů, které umožňují grafickou reprezentaci těchto funkcí v souřadnicových systémech. Poslední kapitola se pak zaobírá přímo příklady z konkrétního počítačového softwaru a tím, na co by uživatel měl brát zřetel aby dosáhl úspěšné grafické reprezentace funkcí.
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Introduction to variables in the teaching of teachers using the method of building schemes in mathematics
Smutná, Anežka ; Vondrová, Naďa (advisor) ; Kvasz, Ladislav (referee)
This thesis deals with an introduction to variables. The aim of the thesis was to compare different approaches to teaching the introduction to variables in teachers who teach a method based on building schemes (known as Hejny method). The theoretical part of the thesis is a search of literature on the topic of introduction to variables and the theoretical background of teaching methods based on building schemes. Further, the thesis analyses textbooks designed for this method with a focus on tasks important for the propaedeutics of the variables. The research itself consisted of interviews with four teachers and observations of the lessons they taught in the 7th and 8th grades of secondary school, the topic of which was an introduction to the "language of letters". In total, there were fifteen lessons taught by these teachers in six classes (2-3 lessons in each class). Data were analyzed by qualitative methods. Although the observed teachers taught using the same method, I identified differences in the approach to the introduction of the variables and in the style of their teaching. There were differences in the organization of the lesson, in the selection of tasks and their style of assignments to pupils, teaching methods and ways in which teachers communicate with pupils. At the moment of entering the...
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Analysis of the main features of the spoken Prague Czech
Synková, Kateřina ; Chromý, Jan (advisor) ; Adam, Robert (referee)
The thesis analyses the main features of Spoken Prague Czech. A recently published literature dealing with Spoken Czech and Spoken Prague Czech was used as for the starting point and as the basis for the study. The hypothesis is based on the aforementioned literature, which was confirmed by voice recordings of Prague native speakers. The acquired data was compiled by the quantitative sociolinguistic methods. The usage of the following terms was examined bych, bychom vs. bysem, bysme, third person plural of the paradigma prosí, trpí, sází, dělá diphthongisation -ý into -ej, instrumental endings of substantive and adjective noun such as -ami, -ama, -y, -emi/-ema, -ími/-íma, -mi/-ma, the usage of endings -m vs. -me within the verb forms of the first person plural indicative and shortening é into í. The outcomes of research show that non-standard varieties generally predominate with an occasional influence of sex and age. Key words: Spoken Prague Czech, Variationist sociolinguistic, variety, variable
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