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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.
321

Simulace idiofonického nástroje / Simulation of Idiofonic System

Múčka, Martin January 2018 (has links)
The thesis deals with dynamic simulation of real bell behavior over time. The model is created according to principles of physical discretization as a spring in the FyDiK3D software. In order for the model to be declared as relevant, it is necessary to prove the behavior of the structures used in the elementary tasks of the mechanics. It shows the correlation between the stiffness of normal and diagonal springs. Describes how to use software import tools to create a model. The resulting model approaches its real bell behavior.
322

Registrace obrazu pomocí metody Optical Flow / Image registration using Optical Flow method

Bistrý, Jan January 2011 (has links)
Registration of medical images is technique, which is developing with new hybrid diagnostic imaging systems. Nowadays is a trend in image registration focused on monomodality and multimodality images registration. The first part of this master’s thesis is intent on present basic information about image registration. Concretely is intending on image transformation, interpolation, criteria function and at optimalization. Further part present realized Optical Flow technique and used “Demon” algorithm for image registration. The next part is focused on presentation of program solution and GUI. In the last section of this master’s thesis is verifying of created program on usual images and real CT images.
323

Modernizace trati Brno – Přerov v okolí Vyškova pro rychlost 200 km/h / Modernization of Brno - Přerov railway line in Vyškov area for speed 200 km/h

Hašek, Jan January 2013 (has links)
The objective of this master´s thesis is a design of modernization of railway line no. 300 Brno – Přerov in Vyškov area and its vicinity for speed 200 km/h. The track section is located between railway station Luleč and Ivanovice na Hané. The track is designed in two variants. The first variant is proposed keeping railway line through Vyškov railway station including necessary modification of the railway station. The second variant suggests keeping track outside Vyškov and a connection with the railway station by bridging is designed.
324

Vyhodnocení geometrických parametrů koleje s podpražcovými podložkami / Assessment of Geometry Parameters of Track with Under Sleeper Pads

Škovranová, Michaela January 2013 (has links)
The diploma thesis applies to under sleeper pads. It researches thein using and benefits in foreign railvway authorities. Further it assesses track geometrical parameters in the trial track section with under sleeper pads in track Havlíčkův Brod - Okrouhlice and in the railway station Planá nad Lužnicí. There were evaluated measurements of vertical alingnment rails by precise leveling and deviations of track geometrical parameters measured by track meusuring car in the diploma thesis.There is expressed an conclusion about the impact of under sleeper pads on track geometric data in the thesis.
325

Návrh modernizace železniční stanice Bohuslavice nad Vláří / Design of Modernization of Bohuslavice nad Vláří Railway Station

Štěpán, Jan January 2014 (has links)
The focus of the thesis is to design a modernization of the Bohuslavice nad Vláří train station. The reconstruction design includes an adjustment of the station head and the geometrical layout of the track for an increase of the track speed to the highest possible value. The design also contains a renewal of the railway superstructure and the structure of the sleeper subsoil, new drainage and platforms. The designed layout ensures a safe access for people with reduced mobility.
326

KALIBRACE ULTRAZVUKOVÉHO PRŮZVUČNÉHO SYSTÉMU VÝPOČETNÍ TOMOGRAFIE / CALIBRATION OF AN ULTRASONIC TRANSMISSIVE COMPUTED TOMOGRAPHY SYSTEM

Filipík, Adam January 2009 (has links)
Tato dizertace je zaměřena na medicínskou zobrazovací modalitu – ultrazvukovou počítačovou tomografii – a algoritmy zlepšující kvalitu zobrazení, zejména kalibraci USCT přístroje. USCT je novou modalitou kombinující ultrazvukový přenos signálů a principy tomografické rekonstrukce obrazů vyvíjených pro jiné tomografické systémy. V principu lze vytvořit kvantitativní 3D obrazové objemy s vysokým rozlišením a kontrastem. USCT je primárně určeno pro diagnózu rakoviny prsu. Autor spolupracoval na projektu Institutu Zpracování dat a Elektroniky, Forschungszentrum Karlsruhe, kde je USCT systém vyvíjen. Jeden ze zásadních problémů prototypu USCT v Karlsruhe byla absence kalibrace. Tisíce ultrazvukových měničů se liší v citlivosti, směrovosti a frekvenční odezvě. Tyto parametry jsou navíc proměnné v čase. Další a mnohem závažnější problém byl v pozičních odchylkách jednotlivých měničů. Všechny tyto aspekty mají vliv na konečnou kvalitu rekonstruovaných obrazů. Problém kalibrace si autor zvolil jako hlavní téma dizertace. Tato dizertace popisuje nové metody v oblastech rekonstrukce útlumových obrazů, kalibrace citlivosti měničů a zejména geometrická kalibrace pozic měničů. Tyto metody byly implementovány a otestovány na reálných datech pocházejících z prototypu USCT z Karlsruhe.
327

Difrakční jevy ve vysílaném optickém svazku / Diffraction Effects in Transmitted Optical Beam

Poliak, Juraj January 2014 (has links)
Dizertačná práca pojednáva o vlnových a elektromagnetických javoch, ku ktorým dochádza pri zatienení eliptického Gausovského zväzku kruhovou apretúrou. Najprv boli z Huygensovho-Fresnelovho princípu odvodené dva modely Fresnelovej difrakcie. Tieto modely poskytli nástroj pre zavedenie kontrastu difrakčného obrazca ako veličiny, ktorá kvantifikuje vplyv difrakčných javov na prevádzkové parametre optického spoja. Následne, pomocou nástrojov elektromagnetickej teórie svetla, boli odvodené štyri výrazy (dva presné a dva aproximatívne) popisujúce geometrický útlm optického spoja. Zároveň boli skúmané tri rôzne prípady odsmerovania zväzku - priečne posunutie a uhlové odsmerovanie vysielača, resp. prijímača. Bol odvodený výraz, ktorý tieto prípady kvantifikuje ako útlm elipticky symetrického Gausovského zväzku. Všetky vyššie uvedené modely boli overené v laboratórnych podmienkach, aby sa vylúčil vplyv iných javov. Nakoniec práca pojednáva o návrhu plne fotonického optického terminálu. Najprv bol ukázaný návrh optického vysielača nasledovaný vývojom optomechanickej sústavy prijímača. Pomocou nástrojov geometrickej a maticovej optiky boli vypočítané parametre spoja a odhad tolerancie pri zamierení spoja.
328

Modèle géométrique déformable pour la simulation et l’optimisation automatique de forme / Geometric modelling and deformation for automatic shape optimisation

Berrini, Elisa 07 June 2017 (has links)
Le contrôle précis des modèles géométriques joue un rôle important dans de nombreux domaines. Pour l’optimisation de forme en CFD, le choix des paramètres de contrôle et la technique de déformation de forme est critique. Nous proposons un modeleur paramétrique avec une nouvelle méthode de déformation d’objets, ayant pour objectif d’être intégré dans une boucle d’optimisation automatique de forme avec un solveur CFD. Notre méthodologie est basée sur une double paramétrisation des objets : géométrique et architecturale. L’approche géométrique consiste à décrire les formes par un squelette, composé d’une famille de courbes B-Splines, appelées courbes génératrice et courbes de section. Le squelette est paramétré avec une approche architecturale. Au lieu d’utiliser les points de contrôle de la représentation classique par courbes B-Splines, la géométrie est contrôlée par ces paramètres architecturaux. Cela permet de réduire considérablement le nombre de degrés de liberté utilisés dans le problème d’optimisation de forme, et permet de maintenir une description haut niveau des objets. Notre technique intègre un contrôle de forme et un contrôle de régularité, permettant d’assurer la génération de nouvelles formes valides et réalistes. Les déformations de la géométrie sont réalisées en posant un problème inverse : déterminer une géométrie correspondant à un jeu de paramètres cibles. Enfin, une technique de reconstruction de surface est proposée. Nous illustrons le modeleur paramétrique développé et intégré dans une boucle d’optimisation automatique de forme sur trois cas : un profil d’aile d’avion, un foil AC45 d’un voilier de course et un bulbe de chalutier de pêche. / The precise control of geometric models plays an important role in many domains. For shape optimisation in CFD, the choice of control parameters and the way to deform a shape are critical. In this thesis, we propose a new approach to shape deformation for parametric modellers with the purpose of being integrated into an automatic shape optimisation loop with a CFD solver. Our methodology is based on a twofold parameterisation: geometrical and architectural. The geometrical approach consist of a skeleton-based representation of object. The skeleton is made of a family of B-Spline curves, called generating curve and section curves. The skeleton is parametrised with an architectural approach: meaningful design parameters are chosen on the studied object. Thus, instead of using the control points of a classical B-spline representation, we control the geometry in terms of architectural parameters. This reduce the number of degrees of freedom and maintain a high level description of shapes. We ensure to generate valid shapes with a strong shape consistency control based on architectural considerations. Deformations of the geometry are performed by solving optimisation problems on the skeleton. Finally, a surface reconstruction method is proposed to evaluate the shape’s performances with CFD solvers. We illustrate the parametric modeller capabilities on three problems, performed with an automatic shape optimisation loop: the wind section of an plane (airfoil), the foil of an AC45 racing sail boat and the bulbous bow of a fishing trawler.
329

Limite de champ moyen et propagation du chaos pour des systèmes de particules avec interaction discontinue / Mean field limit and propagation of chaos for particle system with discontinuous interaction

Salem, Samir 24 October 2017 (has links)
Dans cette thèse, on étudie des problèmes de propagation du chaos et de limite de champ moyen pour des modèles relatant le comportement collectif d'individus ou de particules. Particulièrement, on se place dans des cas où l'interaction entre ces individus/particules est discontinue. Le premier travail établit la propagation du chaos pour l'équation de Vlasov-Poisson-Fokker-Planck 1d. Plus précisément, on montre que la distribution des particules évoluant sur la droite des réels interagissant via la fonction signe, converge vers la solution de l'équation de VPFP 1d, en probabilité par des techniques de type grandes déviations, et en espérance par des techniques de loi des grands nombre. Dans le second travail, on étudie une variante du modèle de Cucker-Smale, où le noyau de communication est l'indicatrice d'un cône dont l'orientation dépend de la vitesse de l'individu. Une estimation de stabilité fort-faible en distance de M.K.W. est obtenue, qui implique la limite de champ moyen. Le troisième travail a consisté à introduire de la diffusion en vitesse dans le modèle précédemment cité. Cependant, il faut ajouter une diffusion tronquée afin de préserver un système dans lequel les vitesses restent uniformément bornées. Finalement, on étudie une variante de l'équation d'agrégation où l'interaction entre individus est donnée par un cône dont l'orientation dépend de la position de l'individu. Dans ce cas on peut seulement donner une estimation de stabilité fort-faible en distance $W_\infty$, et le modèle doit être posé dans un domaine borné dans le cas avec diffusion. / In this thesis, we study some propagation of chaos and mean field limit problems arising in modelisation of collective behavior of individuals or particles. Particularly, we set ourselves in the case where the interaction between the individuals/particles is discontinuous. The first work establihes the propagation of chaos for the 1d Vlasov-Poisson-Fokker-Planck equation. More precisely, we show that the distribution of particles evolving on the real line and interacting through the sign function converges to the solution of the 1d VPFP equation, in probability by large deviations-like techniques, and in expectation by law of large numbers-like techniques. In the second work, we study a variant of the Cucker-Smale, where the communication weight is the indicatrix function of a cone which orientation depends on the velocity of the individual. Some weak-strong stability estimate in M.K.W. distance is obtained for the limit equation, which implies the mean field limit. The third work consists in adding some diffusion in velocity to the model previously quoted. However one must add some truncated diffusion in order to preserve a system in which velocities remain unifomrly bounded. Finally we study a variant of the aggregation equation where the interaction between individuals is also given by a cone which orientation depends on the position of the individual. In this case we are only able to provide some weak-strong stability estimate in $W_\infty$ distance, and the problem must be set in a bounded domain for the case with diffusion.
330

Přisuzované psychologické charakteristiky lidského obličeje v závislosti na socioekonomickém statusu / Assessed psychological characteristics of human face in depedence on socio-economical status

Linke, Lenka January 2011 (has links)
Human face is a complex semantic organ, which among others reflects also human individuality due to the high variance of facial morphologies. This study examines the relationship between psychological characteristics and social status. Moreover, we have analyzed variability in facial form and its relation to a particular social rank. The study was performed on a set of photographs containing 55 pictures of men in a management position. These photographs were evaluated by 47 male (average age - 22 years) and 77 female (average age 21,6 years) respondents. The data were analyzed by means of classical methods of statistical testing as well as geometric morphometrics methods. This study tests whether there is a relation between three psychological characteristics - dominance, attractiveness, trustworthiness - and social status. The effect of perceived dominance and attractiveness on social status were not significant. Nevertheless, we found statistically significant relationship between perceived trustworthiness and social rank. We were not able to detect morphological facial structures, which would distinguish the heads of department from the chief executive directors. However the parametric tests discovered statistically significant differences between the facial morphology of a trustworthy and...

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