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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.
51

Aktivity pro další rozvoj matematicky nadaného žáka na I stupni / Activities for next expansion with mathematically gifted pupil at the primary school

Reslová, Eliška January 2021 (has links)
This diploma thesis is focused on issues connected to possibilities of developement of mathematically talented pupils from the first grade. In the theoretical part there basic terms related to the education of talented pupils in th Czech Republic are summarised and explained. In next part motivation, processes of motivatiom and the most frequent usage of Math competitions as a part of the education in the Czech Republic are presented. The base of the practical part of this diploma thesis is a set of non standardized tasks and problems, whose target is to activate the cognitive developement of talented pupils. Part of the practical part of this thesis is a protocol about an experiment and analysis of the particular tasks and activities for talented pupils. The main aim of this thesis is to emphasise the importance of the developement of talented pupils and compile/form enriching tasks for talented pupils during Maths lessons. KEYWORDS Talent, talent models, motivation, cognitive process, non standardized tasks, aktivity.
52

Monoscopic Analysis of H.E.S.S. Phase II Data on PSR B1259–63/LS 2883

Murach, Thomas 20 October 2017 (has links)
Cherenkov-Teleskope sind in der Lage, das schwache Cherenkovlicht aus Teilchenschauern zu detektieren, die von kosmischen Teilchen mit Energien von ca. 100 GeV bis 100 TeV in der Erdatmosphäre initiiert werden. Das Ziel ist die Detektion von Cherenkovlicht aus Schauern, die von Gammastrahlen erzeugt wurden, der größte Teil der Schauer stammt jedoch von geladenen Teilchen. Im Jahr 2012 wurde das H.E.S.S.-Observatorium in Namibia, bis dahin bestehend aus vier Teleskopen mit 100 m²-Spiegeln, um ein fünftes Teleskop mit einer Spiegelfläche von ca. 600 m² ergänzt. Aufgrund der großen Spiegelfläche besitzt dieses Teleskop die niedrigste Energieschwelle aller Teleskope dieser Art. In dieser Dissertation wird ein schneller Algorithmus namens MonoReco präsentiert, der grundlegende Eigenschaften der Gammastrahlen wie ihre Energien und Richtungen rekonstruieren kann. Dieser Algorithmus kann weiterhin unterscheiden, ob Schauer von Gammastrahlen oder von geladenen Teilchen der kosmischen Strahlung initiiert wurden. Diese Aufgaben werden mit mithilfe von künstlichen neuronalen Netzwerken erfüllt, welche ausschließlich die Momente der Intensitätsverteilungen in der Kamera des neuen Teleskops analysieren. Eine Energieschwelle von 59 GeV und Richtungsauflösungen von 0.1°-0.3° werden erreicht. Das Energiebias liegt bei wenigen Prozent, die Energieauflösung bei 20-30%. Unter anderem mit dem MonoReco-Algorithmus wurden Daten, die in der Zeit um das Periastron des Binärsystems PSR B1259-63/LS 2883 im Jahre 2014 genommen wurden, analysiert. Es handelt sich hierbei um einen Neutronenstern, der sich in einem 3,4-Jahres-Orbit um einen massereichen Stern mit einer den Stern umgebenden Scheibe aus Gas und Plasmen befindet. Zum ersten Mal konnte H.E.S.S. das Gammastrahlenspektrum dieses Systems bei Energien unterhalb von 200 GeV messen. Weiterhin wurde bei erstmaligen Beobachtungen zur Zeit des Periastrons ein lokales Flussminimum gemessen. Sowohl vor dem ersten als auch nach dem zweiten Transit des Neutronensterns durch die Scheibe wurden hohe Flüsse gemessen. Im zweiten Fall wurden Beobachtungen erstmals zeitgleich mit dem Fermi-LAT-Experiment durchgeführt, das wiederholt sehr hohe Flüsse in diesem Teil des Orbits messen konnte. Ein Vergleich der gemessenen Flüsse mit Vorhersagen eines leptonischen Modells zeigt gute Übereinstimmungen. / Cherenkov telescopes can detect the faint Cherenkov light emitted by air showers that were initiated by cosmic particles with energies between approximately 100 GeV and 100 TeV in the Earth's atmosphere. Aiming for the detection of Cherenkov light emitted by gamma ray-initiated air showers, the vast majority of all detected showers are initiated by charged cosmic rays. In 2012 the H.E.S.S. observatory, until then comprising four telescopes with 100 m² mirrors each, was extended by adding a much larger fifth telescope with a very large mirror area of 600 m². Due to the large mirror area, this telescope has the lowest energy threshold of all telescopes of this kind. In this dissertation, a fast algorithm called MonoReco is presented that can reconstruct fundamental properties of the primary gamma rays like their direction or their energy. Furthermore, this algorithm can distinguish between air showers initiated either by gamma rays or by charged cosmic rays. Those tasks are accomplished with the help of artificial neural networks, which analyse moments of the intensity distributions in the camera of the new telescope exclusively. The energy threshold is 59 GeV and angular resolutions of 0.1°-0.3° are achieved. The energy reconstruction bias is at the level of a few percent, the energy resolution is at the level of 20-30%. Data taken around the 2014 periastron passage of the gamma-ray binary PSR B1259-63/LS 2883 were analysed with, among others, the MonoReco algorithm. This binary system comprises a neutron star in a 3.4 year orbit around a massive star with a circumstellar disk consisting of gas and plasma. For the first time the gamma-ray spectrum of this system could be measured by H.E.S.S. down to below 200 GeV. Furthermore, a local flux minimum could be measured during unprecedented measurements at the time of periastron. High fluxes were measured both before the first and after the second transit of the neutron star through the disk. In the second case measurements could be performed for the first time contemporaneously with the Fermi-LAT experiment, which has repeatedly detected very high fluxes at this part of the orbit. A good agreement between measured fluxes and predictions of a leptonic model is found.
53

Asteroseismic inferences from red-giant stars

Themeẞl, Nathalie 28 September 2018 (has links)
No description available.
54

Multivariate semiparametric regression models for longitudinal data

Li, Zhuokai January 2014 (has links)
Multiple-outcome longitudinal data are abundant in clinical investigations. For example, infections with different pathogenic organisms are often tested concurrently, and assessments are usually taken repeatedly over time. It is therefore natural to consider a multivariate modeling approach to accommodate the underlying interrelationship among the multiple longitudinally measured outcomes. This dissertation proposes a multivariate semiparametric modeling framework for such data. Relevant estimation and inference procedures as well as model selection tools are discussed within this modeling framework. The first part of this research focuses on the analytical issues concerning binary data. The second part extends the binary model to a more general situation for data from the exponential family of distributions. The proposed model accounts for the correlations across the outcomes as well as the temporal dependency among the repeated measures of each outcome within an individual. An important feature of the proposed model is the addition of a bivariate smooth function for the depiction of concurrent nonlinear and possibly interacting influences of two independent variables on each outcome. For model implementation, a general approach for parameter estimation is developed by using the maximum penalized likelihood method. For statistical inference, a likelihood-based resampling procedure is proposed to compare the bivariate nonlinear effect surfaces across the outcomes. The final part of the dissertation presents a variable selection tool to facilitate model development in practical data analysis. Using the adaptive least absolute shrinkage and selection operator (LASSO) penalty, the variable selection tool simultaneously identifies important fixed effects and random effects, determines the correlation structure of the outcomes, and selects the interaction effects in the bivariate smooth functions. Model selection and estimation are performed through a two-stage procedure based on an expectation-maximization (EM) algorithm. Simulation studies are conducted to evaluate the performance of the proposed methods. The utility of the methods is demonstrated through several clinical applications.
55

CO₂-balance in the athmosphere and CO₂-utilisation:an engineering approach

Turunen, H. (Helka) 09 August 2011 (has links)
Abstract The subject of the thesis was to analyze by an engineering approach the global CO₂ balance and CO₂ utilisation. The aim was to apply methods and knowledge used in engineering sciences to describe the global CO₂ balance and the role of CO₂ in anthropogenic utilisation applications. Moreover barriers restricting commercialisation of new applications are discussed. These subjects were studied by literature reviews and calculations based on thermodynamics models. Engineering methods have shown to be applicable to describe the global balance of CO₂ and to define by a numerical way the Earth’s system carrying capacity. Direct and indirect actions, which mitigate the overload situation, were derived from the results. To screen out the attractive CO₂ properties in utilisation applications a mapping analysis was carried out. Properties, which enhance mass and heat transfer, are one of the most meaningful characteristics from the chemical engineering point of view. Attractive properties are often achieved at the supercritical state. Engineering thermodynamic methods were used in fluid phase determination of the case studies. Even simple methods are sufficient to advice experimental research work. The thermodynamic knowledge is the basement in creation of industrial scale chemical processes. If detailed information on system properties is needed, a model development due to the special requirements of high pressure systems and CO₂ features is required. This knowledge covers property information from all the components involved in chemical reactions. In addition to engineering knowledge successful technology transfer requires positive social structure as well. Finally, if the humankind is willing to mimic Nature and use light of the Sun as an energy source in engineering systems, development of thermodynamic methods is required also in this area. Especially the work terms, originally defined in classical mechanical thermodynamics and afterwards formulised also in other parts of the engineering fields, play a key role. If this development work is successful, we may see the shift from thermodynamics approach to ‘photodynamics’. Mitigation of global warming is a problem, which needs several kinds of activities. As a result of this study, there are listed a few engineering actions, which have a possibility to contribute to the work towards the carbon neutral society. / Tiivistelmä Väitöskirjatyössä sovelletaan insinööritieteissä käytettyjä metodeja ja tietämystä määriteltäessä ilmakehän CO₂-tase sekä antropogeenisten hyötykäyttökohteiden merkitys teollisissa prosesseissa ja globaaleissa CO₂-virroissa. Lisäksi pohditaan uusien CO₂-hyötykäyttösovellusten kaupallistamiseen liittyviä rajoitteita. Näitä aiheita on tutkittu käymällä läpi tieteellistä kirjallisuutta ja tekemällä laskelmia. Insinööritieteistä tutun taselaskennan avulla tarkastellaan ilmakehän CO₂-virtoja. Sen pohjalta määritetään numeerisesti maapallon CO₂-kantokyky. Tuloksista johdetaan suoria ja epäsuoria toimenpide-ehdotuksia, joiden avulla voidaan lieventää ilmakehän CO₂-ylikuormaa. Kartoitusmenetelmän avulla selvitetään hyötykäytön kannalta edulliset CO₂:n aineominaisuudet. Kemiantekniikan näkökulmasta ominaisuudet, jotka parantavat aineen- ja lämmönsiirtoa, ovat kiinnostavimpia. Nämä ominaisuudet tulevat esille silloin, kun fluidi on ylikriittisessä olomuodossa. Termodynaamisia laskentamenetelmiä sovelletaan esimerkkiseosten olomuodon eli faasin määrityksessä. Tulokset osoittavat, että jopa verraten yksinkertaiset menetelmät antavat tietoja, jotka auttavat ymmärtämään laboratoriokokeiden faasikäyttäytymistä. Teollisen mittakaavan kemiallisten prosessien kehityksessä ja suunnittelussa termodynamiikan hallitseminen on keskeinen edellytys. Jos CO₂:n kiinnostavia ominaisuuksia toivotaan hyödynnettävän teollisesti, korkeapaineisten systeemien termodynaamisen teorian hallinta sekä aineominaisuuksien määrittäminen kaikille systeemiin osallistuville komponenteille ja niiden seoksille nousee merkittävään asemaan. Läpikotainen teorian ja teknisten perusteiden hallitseminen ei vielä takaa menestyksellistä teknologiansiirtoa pienestä suureen mittakaavaan. Lisäksi tarvitaan myönteinen ja kannustava yhteiskuntajärjestelmä. Mikäli tavoitellaan vielä rohkeampaa kehitysnäkymää, tilannetta, jossa luonnon tavoin CO₂-prosessien energianlähteenä käytettäisiin auringonvaloa, havaitaan, että tämäkin askel edellyttäisi termodynaamista menetelmäkehitystä. Keskeinen termodynaaminen konsepti on työ. Työ siirtää energiaa ympäristön ja systeemin välillä. Tämä on määritelty jo klassisessa mekaniikassa; kappaleen siirto tietystä paikasta toiseen. Kemiantekniikassa työlle on kehitetty käyttökelpoisia kaavoja paine–tilavuus–lämpötila-systeemeihin. Mikäli työn elementit kyettäisiin määrittelemään auringonvalon fotoenergialle, avaisi se uusia näkymiä reaktiokemiaan. Silloin termodynamiikan sijaan voitaisiin ehkä mieluummin puhua 'photodynamiikasta'. Ilmaston lämpeneminen on ongelma, jonka lieventämiseen tarvitaan useanlaisia toimia. Etsittäessä tietä kohti hiilineutraalia yhteiskuntaa, insinöörit voivat avustaa suunnan löytämisessä hyödyntämällä tieteenalallaan käytettyjä metodeja ja teorioita sekä tarpeen vaatiessa kehittää niitä edelleen uusille alueille.

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