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Výpočtová simulace válcování v kalibru / Computational simulation of pass rollingHacek, Samuel January 2020 (has links)
Táto diplomová práca sa zaoberá možnosťami výpočtového modelovania valcovania v kalibroch pomocou metódy konečných prvkov. Na začiatku je formulovaná motivácia pre písanie práce a problémová situácia, nasledovaná zostavením systému podstatných veličín. Ďaľšia kapitola popisuje rôzne spôsoby valcovania ako aj samotný valcovací proces. Dôraz je kladený na popis tradičného návrhu kalibrov. Nasledujúca kapitola sa zaoberá teóriou plasticity, plastickým chovaním materiálu a jeho modelovaním v konečnoprvkovom prostredí Abaqus, ktoré je použité vo výpočtovej časti práce. Predstavené sú viaceré modely plasticity, ako aj modely tvárneho porušovania, používané na posúdenie tvárniteľnosti či simuláciu šírenia tvárnej trhliny v materiáli. Práca pokračuje kapitolou zameranou na metódu konečných prvkov, najmä jej explicitný algoritmus, využívaný vo výpočtovej časti práce. Ďaľšia časť je venovaná popisu základných princípov fotoelasticimetrie, tradičnej experimentálnej metódy. Tieto kapitoly zahŕňajú aj popis konečnoprvkovej a experimentálnej fotoplastickej analýzy konkrétneho prípadu valcovania v kalibroch, riešené v predchádzajúcom článku. Použitý výpočtový model je základom nového konečnoprvkového modelu, ktorého tvorbe je predmetom nasledujúcej kapitoly. Naviac sú vytvorené aj dve varianty pôvodného, zjednodušeného výpočtového modelu. S použitím vytvorených výpočtových modelov sú vykonané štrukturálne analýzy a vyhodnotené viaceré výsledky, následne zhrnuté a porovnané s pôvodnými výpočtovými a experimentálnymi výsledkami. Rozbor porovnania výsledkov a zhodnotenie použiteľnosti a spoľahlivosti jednotlivých výpočtových modelov tvoria záver práce.
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An Analogue Baseband Chain for a MagneticTunnel Junction Based RF Signal DetectorMa, Rui, Buhr, Simon, Tibenszky, Zoltán, Kreißig, Martin, Ellinger, Frank 22 November 2021 (has links)
This work presents an analogue baseband (BB) chain for a magnetic tunneling junction (MTJ) based radiofrequency (RF) signal detector fully integrated in a hybrid CMOS-MTJ technology. The BB chain contains a 6 th -order gm-C low-pass filter (LPF), a BB amplifier, a comparator, and a current bank. According to measurement results, the 6 th -order LPF with a cut-off frequency of 10 MHz consumes a very low DC power of 2.41 mW. Its DC power consumption per pole of 0.4 mW is the lowest among the state-of-the-art LPFs. The LPF can be also switched on and off very fast within 110 ns. With the fast switch-ability and the low power consumption, the LPF outperforms the state of the art. Furthermore, the complete BB chain can transform a 2.5 Vpp, 5 Mbps BB signal into digital data with a bit error rate fewer than 1e−6 . The BB chain consumes 2.85mW including all bias circuits. To achieve power efficiency, the BB chain is designed to operate under an aggressive duty-cycling mode. The switch-on time of the BB chain is within 200 ns
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Elektronicky řiditelný aktivní filtr 2. řádu / Electronically controlled active 2-nd order filterŠevčík, Břetislav January 2009 (has links)
The diploma thesis deals with the modern design of the control circuits for digital potentiometers and their application in analog systems. The concept of the digital control is demonstrated on the electronically controlled active 2-nd order filter and programmable oscillator. The proposed design of the active filter describes a programmable active 2-nd order filter Sallen-Key. In this circuit it is possible independently programme cut-off frequency, Q factor and type of approximation with very good accuracy. The circuits of the designed filter and designed oscillator are simulated in PSpice (OrCAD), parasite effects and effects of the real parts are studied. Properties simulated circuits are compare with experimental results. These results appreciate quality and efficiency of the digitally controlled potentiometers in dependence on variable input circuit parameters. Integral part of this project is author’s universal control program called Digipot and comunications interface for many types of digital potentiometers with I2C, SPI or Up/Down interface. It is possible to use this device for many applications. The constructional details of the filter are presented at the end of this work. The software equipment is availability on enclosed CD.
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Koincidenční detektor FM - laboratorní přípravek / FM Coincidence Detector - Laboratory EquipmentMlčoch, Jiří January 2009 (has links)
This work is aimed at an analysis of frequency demodulation, design, simulation, and construction of a coincidence demodulator. Chapter 1 explains the basic characteristics of frequency modulated (FM) signals and provides an overview of the required signal bandwidth, the signal spectrum, and the signal-to-noise ratio after demodulation. Chapter 2 describes each type of FM demodulator separately, and it includes all significant types of demodulator for FM radio broadcast. The function of the coincidence demodulator and its characteristics are explained in detail. Chapter 3 contains a theoretical solution of the phase shift network. Calculated values of the circuit elements are verified by simulation with a view to the total harmonic distortion of the demodulator output signal. Chapter 4 describes the front-end circuit of the receiver. Here, the filter design and the mixer circuit description are provided. The final part of the thesis presents the applicable laboratory task.
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Filtry vyšších řádů s proudovými zrcadly / Current mirror higher-order filtersNovotný, Matouš January 2010 (has links)
Submitted work engages in suggestion of frequency-selection filters with usage of more active elements of the MCMI (Multi-Output Current Mirror and inverter). The preamble of thesis is applied to theory of frequency-selection filters and possible usage of them. The projected circuit layouts with the active elements are discussed in terms of the impact of parasitic properties of the real models. The part of thesis is numerical suggestion of found solutions, their simulation in suitable program.
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Filtr na bázi vlnovodu integrovaného do substrátu / Substrate integrated waveguide filterVyskočil, Jiří January 2011 (has links)
In this thesis is discussed a filter design of a band-pass substrate integrated waveguide filter on the frequency of 5 GHz. It also includes design theory, filter synthesis, filter analysis in the program CST Microwave Studio® and the results of measurement on a vector network analyzer. The analysis results are compared with the measured results. Good agreement between simulated and measured results is observed.
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Vizuální efekty ve 3D aplikacích / Visual Effects in 3D ApplicationsDuží, Martin January 2014 (has links)
This master's thesis deals with the creation of visual effects in 3D graphics applications. Rendering scenes using rasterization method and OpenGL library is assumed. The theoretical part describes several selected effects and then analyzes the approach used for their implementation. It focuses on the principles of rendering passes. Subsequently, the thesis focuses on the development of a software library which aims to simplify the process of programming effects. The resulting library reduces the time and knowledge required for the creation of effects. Automatic shader code generation is performed. Substantial feature is also the possibility to combine definitions of effects into a single unit.
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Návrh rekonstrukce jezu Přízřenice na řece Svratce / Reconstruction of the Přízřenice weir at the Svratka riverTrněný, Michal January 2017 (has links)
The Diploma Thesis deals with the design of rekonstruction of the controlled weir ´´Prizrenice“ on the river Svratka to a new gate weir structure. The first part focuses on teoretical intro and the processing of data on the area of interest and the selection of appropriate design solution for the reconstruction of the weir, where there are described several types of movable gate. As a part of sollution, there will be design of small hydro power station. At the end of this part the current condition of the buildings and the channel of the Svratka river in the area of interest is evaluated. In the second part, the Thesis deals with the design of the gate weir structure and its subsequent assessment. At first, the solid substructure and the height of the gate is designed and assessed. Subsequently, the stilling basin is designed and in conclusion, the overall stability of the designed structure is assessed.
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Exploitation d’informations riches pour guider la traduction automatique statistique / Complex Feature Guidance for Statistical Machine TranslationMarie, Benjamin 25 March 2016 (has links)
S'il est indéniable que de nos jours la traduction automatique (TA) facilite la communication entre langues, et plus encore depuis les récents progrès des systèmes de TA statistiques, ses résultats sont encore loin du niveau de qualité des traductions obtenues avec des traducteurs humains.Ce constat résulte en partie du mode de fonctionnement d'un système de TA statistique, très contraint sur la nature des modèles qu'il peut utiliser pour construire et évaluer de nombreuses hypothèses de traduction partielles avant de parvenir à une hypothèse de traduction complète. Il existe cependant des types de modèles, que nous qualifions de « complexes », qui sont appris à partir d'informations riches. Si un enjeu pour les développeurs de systèmes de TA consiste à les intégrer lors de la construction initiale des hypothèses de traduction, cela n'est pas toujours possible, car elles peuvent notamment nécessiter des hypothèses complètes ou impliquer un coût de calcul très important. En conséquence, de tels modèles complexes sont typiquement uniquement utilisés en TA pour effectuer le reclassement de listes de meilleures hypothèses complètes. Bien que ceci permette dans les faits de tirer profit d'une meilleure modélisation de certains aspects des traductions, cette approche reste par nature limitée : en effet, les listes d'hypothèses reclassées ne représentent qu'une infime partie de l'espace de recherche du décodeur, contiennent des hypothèses peu diversifiées, et ont été obtenues à l'aide de modèles dont la nature peut être très différente des modèles complexes utilisés en reclassement.Nous formulons donc l'hypothèse que de telles listes d'hypothèses de traduction sont mal adaptées afin de faire s'exprimer au mieux les modèles complexes utilisés. Les travaux que nous présentons dans cette thèse ont pour objectif de permettre une meilleure exploitation d'informations riches pour l'amélioration des traductions obtenues à l'aide de systèmes de TA statistique.Notre première contribution s'articule autour d'un système de réécriture guidé par des informations riches. Des réécritures successives, appliquées aux meilleures hypothèses de traduction obtenues avec un système de reclassement ayant accès aux mêmes informations riches, permettent à notre système d'améliorer la qualité de la traduction.L'originalité de notre seconde contribution consiste à faire une construction de listes d'hypothèses par passes multiples qui exploitent des informations dérivées de l'évaluation des hypothèses de traduction produites antérieurement à l'aide de notre ensemble d'informations riches. Notre système produit ainsi des listes d'hypothèses plus diversifiées et de meilleure qualité, qui s'avèrent donc plus intéressantes pour un reclassement fondé sur des informations riches. De surcroît, notre système de réécriture précédent permet d'améliorer les hypothèses produites par cette deuxième approche à passes multiples.Notre troisième contribution repose sur la simulation d'un type d'information idéalisé parfait qui permet de déterminer quelles parties d'une hypothèse de traduction sont correctes. Cette idéalisation nous permet d'apporter une indication de la meilleure performance atteignable avec les approches introduites précédemment si les informations riches disponibles décrivaient parfaitement ce qui constitue une bonne traduction. Cette approche est en outre présentée sous la forme d'une traduction interactive, baptisée « pré-post-édition », qui serait réduite à sa forme la plus simple : un système de TA statistique produit sa meilleure hypothèse de traduction, puis un humain apporte la connaissance des parties qui sont correctes, et cette information est exploitée au cours d'une nouvelle recherche pour identifier une meilleure traduction. / Although communication between languages has without question been made easier thanks to Machine Translation (MT), especially given the recent advances in statistical MT systems, the quality of the translations produced by MT systems is still well below the translation quality that can be obtained through human translation. This gap is partly due to the way in which statistical MT systems operate; the types of models that can be used are limited because of the need to construct and evaluate a great number of partial hypotheses to produce a complete translation hypothesis. While more “complex” models learnt from richer information do exist, in practice, their integration into the system is not always possible, would necessitate a complete hypothesis to be computed or would be too computationally expensive. Such features are therefore typically used in a reranking step applied to the list of the best complete hypotheses produced by the MT system.Using these features in a reranking framework does often provide a better modelization of certain aspects of the translation. However, this approach is inherently limited: reranked hypothesis lists represent only a small portion of the decoder's search space, tend to contain hypotheses that vary little between each other and which were obtained with features that may be very different from the complex features to be used during reranking.In this work, we put forward the hypothesis that such translation hypothesis lists are poorly adapted for exploiting the full potential of complex features. The aim of this thesis is to establish new and better methods of exploiting such features to improve translations produced by statistical MT systems.Our first contribution is a rewriting system guided by complex features. Sequences of rewriting operations, applied to hypotheses obtained by a reranking framework that uses the same features, allow us to obtain a substantial improvement in translation quality.The originality of our second contribution lies in the construction of hypothesis lists with a multi-pass decoding that exploits information derived from the evaluation of previously translated hypotheses, using a set of complex features. Our system is therefore capable of producing more diverse hypothesis lists, which are globally of a better quality and which are better adapted to a reranking step with complex features. What is more, our forementioned rewriting system enables us to further improve the hypotheses produced with our multi-pass decoding approach.Our third contribution is based on the simulation of an ideal information type, designed to perfectly identify the correct fragments of a translation hypothesis. This perfect information gives us an indication of the best attainable performance with the systems described in our first two contributions, in the case where the complex features are able to modelize the translation perfectly. Through this approach, we also introduce a novel form of interactive translation, coined "pre-post-editing", under a very simplified form: a statistical MT system produces its best translation hypothesis, then a human indicates which fragments of the hypothesis are correct, and this new information is then used during a new decoding pass to find a new best translation.
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Coercive agrarian work in South Africa, 1948 - 1965 : 'farm labour scandals'?Muller, Cornelis Hermanus 09 December 2011 (has links)
This dissertation puts into historical context allegations of farm labour abuse during the period 1948 to 1960 on the eastern Transvaal Highveld. It not only gives an exposition of these events, but importantly analyses these allegations of abuse in the context of the South African government’s intervention into farm labour for this period. The dissertation, however, first gives an overview of the government’s policies of regulating and providing farmers with black labour in the period 1910 to 1948. It deals specifically with the dubious measures introduced and coercive actions taken by the National Party government after 1948 to provide farmers with “cheap and plentiful labour”. The reactions to the accusations of abuse by the South African government, the farmers, the conservative, liberal and leftist press, and other independent bodies, such as the churches, Black Sash and the South African Institute of Race Relations, are also explored. The reaction of the African National Congress and the Potato Boycott launched in 1959 by this organisation in response to the mistreatment of farm labourers, also receives specific attention. It concludes with a discussion of how the farm labour scandals and the reaction during the 1950s and more specifically the Potato Boycott of 1959 are still relevant today by considering the contested nature of the commemoration of this event in 2009 AFRIKAANS : Hierdie verhandeling plaas bewerings van die misbruik van plaasarbeid gedurende die periode 1948 tot 1960 op die oostelike Transvaalse Hoëveld in historiese konteks. Dit bied nie net ‘n uiteensetting van hierdie gebeure nie, maar ontleed dié bewerings van mishandeling teen die agtergrond van die Suid-Afrikaanse regering se ingryping ten opsigte van plaasarbeid vir dié tydperk. Die verhandeling bied ten eerste ‘n oorsig van die regering se beleid van die regulering en voorsiening van swart arbeid aan boere gedurende die periode 1910 tot 1948. Dit handel spesifiek oor die twyfelagtige dwangmaatreëls wat deur die Nasionale Partyregering na 1948 geïmplementeer is om boere van “goedkoop en voldoende arbeid” te voorsien. Die reaksies op die bewerings van mishandeling deur die Suid-Afrikaanse regering, die boere, die konserwatiewe, liberale en linkse pers, as ook ander selfstandige instansies, soos die kerke, Black Sash en die Suid-Afrikaanse Instituut van Rasseverhoudinge word ook ondersoek. Die reaksie van die African National Congress en die aartappelboikot wat deur die organisasie in 1959 van stapel gestuur is in reaksie op die mishandeling van plaaswerkers, work ook ontleed. Die studie sluit af met ‘n bespreking van hoe die plaasarbeidskandale, die reaksie in die 1950s en meer spesifiek die aartappelboikot van 1959, steeds vandag relevant is teen die agtergrond van die omstrede herdenking van die gebeurtenis in 2009. / Dissertation (MHCS)--University of Pretoria, 2011. / Historical and Heritage Studies / unrestricted
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