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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Vysoce entropické slitiny Cantorova typu zpevněné disperzí nitridů / Nitride dispersion strengthened Cantor´s high entropy alloys

Havlíček, Štěpán-Adam January 2020 (has links)
High Entropy Alloy (HEA) is a class of construction steels based on the mixing of five or more elements in approximately equimolar ratios. Despite the ambiguity of their future use, HEAs represent a significantly new group of construction materials that are currently receiving a great deal of attention. Single-phase HEAs fail when used at elevated tempera-tures. The improvement of their high-temperature resistance was achieved by introducing a dispersion of oxides Al2O3 and Y2O3. To generalize the positive effect of dispersions on the mechanical properties at elevated temperatures, particles of a similar nature were cho-sen. These were dispersed particles of nitrides: hardness-incompatible AlN and hardness-compatible BN. The particles were evenly distributed inside the alloys by mechanical al-loying and compacted by SPS (Spark Plasma Sintering). The new structural alloy reached a density higher than 96.5 % and brought an increase in yield strength at room tempera-ture of up to 67 % and 40 % at elevated temperatures, while maintaining a homogeneous distribution of input powders.
42

Analýza trojrozměrných objektů metodou konečných prvků v časové oblasti / Analysis of three-dimensional objects by time-domain finite elements

Syrový, Jiří January 2011 (has links)
This thesis is aimed on three-dimensional finite element time domain analysis. Vector finite elements are used for analysis of cavity resonator made from PEC and filled with vacuum. Results are compared with classical “nodal” finite elements and with published literature.
43

Kontrola průmyslové montáže pomocí kamery / Automated Camera Measurement in the Industrial Process

Sedlář, Martin January 2012 (has links)
This master's thesis deals with questions about contactless camera detection of presence and right direction of assembled parts in the industry process. The main aim of this work is design and realization of graphical user interface and algorithm for automated camera measurement system in the industrial process.
44

Horský hotel v Beskydech / Mountain hotel in Beskydy

Kubášková, Barbora January 2014 (has links)
This thesis solves design of timber structure of mountain hotel in Beskydy. The hotel is two-storey building with residential attic and no cellar. The ground plan of the building is about 15x26 m and height of the building is 14,76 m. The type of roof timbers was chosen from two options. There was used structural timber of the strength class C24, glued laminated timber of the strength class GL24 and steel S235. Program Scia Engineer was used for the static analysis of the structure. There was made only linear calculation.
45

Kryptoanalýza postranními kanály / Side Channel Cryptanalysis

Martinásek, Zdeněk January 2013 (has links)
Side channels fundamentally changes the view of the cryptographic system security in cryptography. It is not enough to analyze the security algorithm only from a mathematical point of view using abstract models but it is necessary to focus on the implementation of the algorithms. The introduction of the thesis deals with the basic terms, principles of side channel attacks and basic clasification of side channels. The following chapter describes the objectives of the thesis. The main goal of the thesis is to propose and experimentally verify a new power analysis method whish will use the neural network. This main goal was based on the realized analyzes presented in the following chapters. These chapters contain a detailed analysis of currently used power analysis and analysis of AES encryption algorithm. AES was selected becouse the algorithm is resistant to the conventional cryptoanalysis. The following section describes the experimental results of the optimization of existing methods, the influence of the parameters affecting power consumption and the results of the proposed analysis using neural networks. This section includes the discussion of the results. This type of side channel attack has not been published yet thus it is a completely new idea. The final goal of the thesis was to summarize the possible countermeasures protecting against the side channel attacks.
46

Nástroj pro podporu analýzy rizik v informační bezpečnosti / Tool for Risk Analysis Support in Information Security

Plíšek, Martin January 2012 (has links)
The master thesis deals with the development of the tool for risk analysis support in information security. At first we perform a theoretical basis for security development of lifecycle process (SDL). Afterwards the theory of risk analysis based on fault tree analysis is described. Considering this knowledge base system was designed and implemented. Next chapter describes the best practice refer to the typical example of use and presents the potencial using of this tool in practice. Final chapter deals with the possibility of future expansion of this application.
47

Empirický výzkum reprezentace historických informací v médiu počítačových her, jejich vnímání uživatelem a jejich intrapersonální vzdělávací výsledky / Empirical research on the representation of historical information in the medium of computer games, their user reception, and intrapersonal learning outcomes

Kolek, Lukáš January 2020 (has links)
This dissertation investigates whether video games are able to affect players' attitudes and information behaviour towards depicted historical topics in games over the short- and long-term. We collected data from a sample of 148 young adults. As far as we know, there is currently no study of such a scale focused on historical games. We used, as an intervention tool, a modification of the serious game Czechoslovakia 38-89: Borderlands that deals with the expulsion of the Sudeten Germans from the former Czechoslovakia after WWII. The game is based on historical research providing players with multiple perspectives on the depicted topics. Our control group played a similar game, but where the narrative was unrelated to any depicted historical event from Czechoslovakia 38-89: Borderlands. In the empirical part of the study, we measured explicit and implicit attitude change and information behaviour change towards the expulsion of the Sudeten Germans. Results showed more negative pretest-posttest explicit attitude changes towards the expulsion on a general level (d = -0.34; p = .022) and a specific level (d = -0.53; p = .001) in the experimental group compared to the control group. Over the long-term, group differences in attitude change remained significant for the specific level (d = -0.44; p = .014),...
48

Mechanické vlastnosti zemin z pískovny Kolný v třeboňské pánvi / Mechanical properties of soils of the Kolný sand pit

Englmaierová, Martina January 2010 (has links)
This thesis originated as a part of the PhD research carried out by Mgr. Radek Suchomel. To calibrate a hypoplastic model for granular materials a large number of laboratory tests was needed and a part of the testing constitutes the present thesis. The hypoplastic model by von Wolffersdorff (1996) has eight materials parameters. The critical state fiction angle φc', which was obtained directly by the measurement of the angle of repose, is one of the eight parameters. Other parameters are determined form the results of experiments and empirically. Aim of this thesis was to carry out field and laboratory tests, to determine selected soil properties and to interpret them with regard to the variability of the soil in the selected face of the sand pit. The material for investigation comes from the south part of the Cretaceous Třeboň Basin in the South Bohemia from the Kolný sand pit. The pit is located in the upper part of the Klikov layers. The fluvial layers are characterised by rhythmical variation of gravely sands, sands and sands with dark grey clayey inclusion. Samples were taken in the face of the sand pit with the dimensions of 9 x 36 m. The following tests were performed: drained triaxial compression test (38 samples), oedometric compression test (38 samples), measurement of the angle of repose...
49

Informační chování a učení v kontextu nových medií: Digitální hry a simulace jako komplexní systémy pro reprezentaci informací / Information behavior and learning in the context of new media: Digital games and simulations as complex systems for information representation

Buchtová, Michaela January 2014 (has links)
This dissertation considers digital games and simulations as complex systems of information representation and explores their specific aspects influencing the process of knowledge acquisition. It focuses on process of mental model creation, information behavior and situational emotional and cognitive engagement. The methodological approach is grounded in variety of disciplines including information science, educational science, new media studies and computer science. The main method used is educational experiment. The use of digital game-based and non-digital game-based educational intervention is compared to similar program based on traditional schooling methods and classic lectures. The experiment outcomes are divided into four large segments exploring influence of digital games on process of mental models creation, motivation for future information behavior, situational emotional experience and social interaction.
50

Optimalizace parametrů sekundárního chlazení plynulého odlévání oceli / Optimization of Secondary Cooling Parameters of Continuous Steel Casting

Klimeš, Lubomír January 2014 (has links)
Continuous casting is a dominant production technology of steelmaking which is currently used for more that 95% of the world steel production. Mathematical modelling and optimal control of casting machine are crucial tasks in continuous steel casting which directly influence productivity and quality of produced steel, competitiveness of steelworks, safety of casting machine operation and its impact on the environment. This thesis concerns with the development and implementation of the numerical model of temperature field for continuously cast steel billets and its use for optimal control of the casting machine. The numerical model was developed and implemented in MATLAB. Due to computational demands the model was parallelized by means of the computation on graphics processing units NVIDIA with the computational architecture CUDA. Validation and verification of the model were performed with the use of operational data from Trinecke zelezarny steelworks. The model was then utilized as a part of the developed model-based predictive control system for the optimal control of dynamic situations in the casting machine operation. The behaviour of the developed control system was examined by means of dynamic model situations that have confirmed the ability of the implemented system to optimally control dynamic operations of the continuous casting machine. Both the numerical model of the temperature field and the model-based predictive control system have been implemented so that they can be modified for any casting machine and this allows for their prospective commercial applications.

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