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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.
231

Vizualizace černoděrových prostoročasů / Visualization of black hole spacetimes

Maixner, Michal January 2018 (has links)
This work is focused on visualisation of Schwarzschild, Reissner- Nordström and Kerr black hole. The two-dimensional conformal diagram was constructed. In the case of Kerr black hole, the causal structure was visualized by intersection of chronological future of given point in spacetime with hyper- surfaces of constant value of Boyer-Lindquist coordinate t. Conformal diagram for Kerr black hole was constructed only in the neighbourhood of outer event horizon. Then the causal diagram, which is analogous to conformal diagram for Reissner-Nordström black hole was constructed. In all cases two-dimensional spa- celike hypersurfaces were chosen that were embedded into Euclidean space. The interpretation of time evolution of black hole universe was given to a sequence of such embedded hypersurfaces. In the case of Kerr black hole the embedding of outer ergosphere and outer event horizon were also constructed. 1
232

Dispersion Characteristics of One-dimensional Photonic Band Gap Structures Composed of Metallic Inclusions

Khodami, Maryam 22 August 2012 (has links)
An innovative approach for characterization of one dimensional Photonic Band Gap structures comprised of metallic inclusions (i.e. subwavelength dipole elements or resonant ring elements) is presented. Through an efficient S- to T-parameters conversion technique, a detailed analysis has been performed to investigate the variation of the dispersion characteristics of 1-D PBG structures as a function of the cell element configuration. Also, for the first time, the angular sensitivity of the structure has been studied in order to obtain the projected band diagrams for both TE and TM polarizations. Polarization sensitivity of the subwavelength cell element is exploited to propose a novel combination of elements which allows achieving PBGs with simultaneous frequency and polarization selectivity. The proposed approach demonstrates that the dispersion characteristic of each orthogonal polarization can be independently adjusted with dipole elements parallel to that same polarization. Generally, the structure has potential applications in orthomode transducer, and generally whenever the polarization of the incoming signal is to be used as a means of separating it from another signal in the same frequency band that is of orthogonal polarization. The current distribution and the resonance behavior of the ring element is studied and the effect of resonance on dispersion characteristics of 1-D PBGs composed of rings is investigated for the first time, for both individual and coupled rings. Interestingly, it is observed that 1-D PBG composed of resonant elements consistently has a bandgap around the resonant frequency of the single layer structure.
233

Samrådsunderlag för Lysekilsprojektet : Forskning och utveckling av vågkraft

Ström, Simon January 2014 (has links)
The aim of this research is to find out what environmental impact a wave power park has on the Swedish west coast by creating a consultation paper (”Samrådsunderlag”) for the Lysekilproject at Uppsala University. To highlight the complexity of the problem a system analytic approach was used and illustrated by a Causal Loop Diagram. The overall assessment of the Lysekilprojects wave power park at the Swedish west coast is that it will have a low impact on the environment. This is due to the relative small size of the wave power park and some technical solutions made with the environmental aspect in mind. Artificial reefs and a sanctuary for marine species are effects created by the wave power park and in the longer term the impact will give access to an untapped source of renewable energy, wave energy. Thus reducing the need of fossil fuels and making it possible to reach the Swedish national environmental goals. / Lysekilsprojektet
234

Rizika řízení průběhu zakázky v podniku / Risks of order processing in company

Bartoňková, Lucie January 2016 (has links)
This thesis is dealing with the issue of risk management during order processing in manufacturing company, which is focused on textile production. Introduction of thesis is presenting theroretical basis. Practical part of the thesis is dealing with company introduction organizational structure of the body, product range, order progressing, OSH policy and environmental policy. Tools chosen for risk assessment techniques - analysis of the causes and consequences (Ishikawa diagram), analysis of possible errors and their consequences (FMEA) and the Pareto chart. The thesis aims to analyze the risks and for the most significant risks to process proposals for their elimination.
235

Dinâmica de redes de osciladores de Fitzhugh-Nagumo / Dinamic of Fitzhugh-Nagumo oscilator network

Santos, Juliana Vicente dos 01 March 2013 (has links)
Made available in DSpace on 2016-12-12T20:15:49Z (GMT). No. of bitstreams: 1 Juliana Vicente.pdf: 26659692 bytes, checksum: 42c72bc287e017fe62aec1549942e15b (MD5) Previous issue date: 2013-03-01 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The Fitzhugh-Nagumo model originally consists of two non-linear differential equations, which simulate the behavior of nerve impulse conduction through the neuronal membrane. In this work, we study the dynamical behavior of coupled neuron networks modeled by equations of Fitzhugh-Nagumo, in the numerical viewpoint. The numerical simulations were made considering networks of two, three and four neurons coupled unidirectionally and bidirectionally, for which parameter spaces, isoperiodic diagrams and bifurcation diagrams were built. In the parameter spaces and isoperiodic diagrams we investigated the dynamics of the variation between coupling strength of the neural systems and any other parameters of system, calculating the Lyapunov exponents and the local maximum of a variable respectively. The results showed the existence of periodic structures, self-organized arranged sequentially in a period-adding bifurcation cascade immersed in chaotic regions. Internally these structures undergo bifurcations by period-doubling. In the case of the two neurons model unidirectionally coupled, we observe the formation of periodic structures arranged in period-adding bifurcation cascade. Finally we show that in some cases the networks of three and four neurons the occurrence of hyperchaos, were observed in the dynamics of the systems. / O modelo de Fitzhugh-Nagumo é composto originalmente por um sistema de duas equações diferenciais não-lineares, que simulam o comportamento de condução do impulso nervoso através da membrana neural. Neste trabalho estudamos numericamente o comportamento dinâmico de redes de neurônios acoplados, modeladas pelas equações de Fitzhugh-Nagumo. Consideramos redes de dois, três e quatro neurônios acoplados unidirecionalmente e bidirecionalmente, para as quais foram construídos espaços de parâmetros dos expoentes de Lyapunov, diagramas isoperíodos e diagramas de bifurcação. Nos espaços de parâmetros e diagramas isoperiódicos investigamos a dinâmica da variação entre a intensidade de acoplamento dos sistemas de neurônios e um outro parâmetros quaisquer do sistema, calculando o espectro de Lyapunov e os máximos locais de uma variável, respectivamente. Os resultados evidenciaram a existência de estruturas auto-similares arranjadas sequencialmente em cascatas de bifurcação por adição de período imersas em regiões caóticas. Internamente, as estruturas periódicas exibem cascatas de bifurcações por dobramento de período. No caso do modelo para dois neurônios acoplados unidirecionalmente existe a formação de estruturas periódicas em camada, arranjadas em cascatas de bifurcação por adição de período. Finalmente mostramos que, para as redes de três e quatro neurônios, existe a ocorrência de regiões de hipercaos na dinâmica dos sistemas.
236

Návrh projektu a aplikace metodiky projektového managementu v podniku / Project Design and Application of Methodology of Project Management in the Company

Entlová, Radka January 2013 (has links)
The master’s thesis considers a project proposal for development of application software for customer’s needs. The thesis specifies the basic concepts and methods of project management. It contains analysis of the current state of company and its environment. The thesis focuses on the project proposal.
237

Projektové řízení ve společnosti Hella Autotechnik Nova, s. r. o / Project Management in the Company Hella Autotechnik Nova, s. r. o

Bílek, Pavel January 2015 (has links)
The master´s thesis deals with the problems of project management. Specifically, it deals with analysis of current state and draft measures for project management at company Hella Autotechnik Nova, s. r. o, which is necessary to optimizing for management of development projects in company technical centre. The thesis uses mainly procedures and project management methods defined by the PMI (Project Management Institute).
238

Využití hydroformingu při vytváření strukturovaného povrchu solárního panelu / Utilization of hydroforming technology to create a structured surface of solar panel

Řiháček, Jan Unknown Date (has links)
The doctoral thesis deals with utilization of hydroforming technology for manufacturing of a new type of solar absorber, which has directly flow meandering structure and a structured surface consisting of pyramidal elements. Austenitic stainless steel X5CrNi18-10 is used as a material for absorbers production. At the beginning of the thesis, a literary research is performed, which is focused on particular methods of hydroforming technology, their applicability for this problem, forming limits determination and usability of numerical simulation. Based on the literature study, the production technology was developed by using parallel hydroforming technology and it was optimized by using a numerical simulation in the ANSYS software. Hydroforming parameters for two variants of the structured surface with pyramidal cavities with apex angle of 90° and 60° were determined from the calculations and the material tests.
239

The contribution of the teaching-learning environment to the development of self-regulation in learning

Mahlangu, Peter Patrick 29 May 2008 (has links)
This study focuses in the students’ perception of self-regulation in learning as influenced by the teaching-learning-environment. The study was conducted at the University of Pretoria. The participants in the study were first year students registered for a second semester module in Educational Psychology in the faculty of education. The size of the sample was nine (22,5%) male students and 31 (77,5%) female students. At the time of participation, the participants had attended university for a period of at least six months and had written tests and one examination. The Interactive Qualitative Analysis (IQA) method as described by Northcutt and McCoy (2004) was used to elicit participants’ knowledge and experiences of the research phenomenon. The participants were expected to complete an instrument that required them to indicate the direction of three relationships between all combinations of the themes which were selected on the basis of literature review. The participants were required to indicate how they perceive the nature of relationships between themes that were developed by the researcher as associated with self-regulated learning in a system of cause and effect. The main findings of the study indicate that language of instruction and student personality are primary drivers that determine the academic success of the students. The two themes exert great influence on other themes that are involved in the teaching-learning environment. Academic success emerged as primary outcome which means that it is a theme that depends to a large extent on how the other themes that exist in the teaching-learning environment are structured. The findings of the study indicate that there is no significant difference that exists in the male and female participants’ perception of the factors that influence self-regulation in learning. In both sample primary drivers were language of instruction and students’ personality and the primary outcome was academic success. / Dissertation (MEd (Educational Psychology))--University of Pretoria, 2008. / Educational Psychology / unrestricted
240

Dispersion Characteristics of One-dimensional Photonic Band Gap Structures Composed of Metallic Inclusions

Khodami, Maryam January 2012 (has links)
An innovative approach for characterization of one dimensional Photonic Band Gap structures comprised of metallic inclusions (i.e. subwavelength dipole elements or resonant ring elements) is presented. Through an efficient S- to T-parameters conversion technique, a detailed analysis has been performed to investigate the variation of the dispersion characteristics of 1-D PBG structures as a function of the cell element configuration. Also, for the first time, the angular sensitivity of the structure has been studied in order to obtain the projected band diagrams for both TE and TM polarizations. Polarization sensitivity of the subwavelength cell element is exploited to propose a novel combination of elements which allows achieving PBGs with simultaneous frequency and polarization selectivity. The proposed approach demonstrates that the dispersion characteristic of each orthogonal polarization can be independently adjusted with dipole elements parallel to that same polarization. Generally, the structure has potential applications in orthomode transducer, and generally whenever the polarization of the incoming signal is to be used as a means of separating it from another signal in the same frequency band that is of orthogonal polarization. The current distribution and the resonance behavior of the ring element is studied and the effect of resonance on dispersion characteristics of 1-D PBGs composed of rings is investigated for the first time, for both individual and coupled rings. Interestingly, it is observed that 1-D PBG composed of resonant elements consistently has a bandgap around the resonant frequency of the single layer structure.

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