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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.
71

Statistics of Multivariate Extremes with Applications in Risk Management

Herrera, Rodrigo 30 October 2009 (has links) (PDF)
The contributions of this thesis have mainly a dual purpose: introducing several multivariate statistical methodologies where in the major of the cases only stationary of the random variables is assumed, and also highlight some of the applied problems in risk management where extreme value theory may play a role. Mostly every chapter is selfcontained, they have its own more detailed introduction and short conclusion. / Die Kontributionen von dieser Dissertation haben ein doppeltes Ziel: die Darstellung von vielen multivariaten statistischen Verfahren, wobei in der Mehrheit der Fälle nur Stationarität von den Zufallsvariablen angenommen wurde, und die Anwendungen in Risikomanagement in welchem Extremwerttheorie eine wichtige Rolle spielen könnte. Die Struktur der Arbeit ist eigenständig, mit einer detaillierten Einführung und kurzen Zusammenfassung in jedem Kapitel.
72

Advanced Regression Methods in Finance and Economics: Three Essays

Hofmarcher, Paul 29 March 2012 (has links) (PDF)
In this thesis advanced regression methods are applied to discuss and investigate highly relevant research questions in the areas of finance and economics. In the field of credit risk the thesis investigates a hierarchical model which allows to obtain a consensus score, if several ratings are available for each firm. Autoregressive processes and random effects are used to model both a correlation structure between and within the obligors in the sample. The model also allows to validate the raters themselves. The problem of model uncertainty and multicollinearity between the explanatory variables is addressed in the other two applications. Penalized regressions, like bridge regressions, are used to handle multicollinearity while model averaging techniques allow to account for model uncertainty. The second part of the thesis makes use of Bayesian elastic nets and Bayesian Model Averaging (BMA) techniques to discuss long-term economic growth. It identifies variables which are significantly related to long-term growth. Additionally, it illustrates the superiority of this approach in terms of predictive accuracy. Finally, the third part combines ridge regressions with BMA to identify macroeconomic variables which are significantly related to aggregated firm failure rates. The estimated results deliver important insights for e.g., stress-test scenarios. (author's abstract)
73

The influence of some ancient philosophical and religious traditions on the soteriology of early Christianity

Gibson, Jan Albert 08 1900 (has links)
When reading the Bible in an independent way, i.e., not through the lenses of any official Church dogma, one is amazed by the many voices that come through to us. Add to this variety the literary finds from Nag Hammadi, as well as the Dead Sea Scrolls, then the question now confronting many spiritual pilgrims is how it came about that these obviously diverse theologies, represented in the so-called Old and New Testaments, were moulded into only one "orthodox" result. In what way and to what degree were the many Christian groups different and distinctive from one another, as well as from other Jewish groups? Furthermore, what was the influence of other religions, Judaism, the Mysteries, Gnostics and Philosophers on the. development, variety of groups and ultimately on the consolidation of "orthodox" soteriology? / Philosophy Practical and Systematic Theology / Th.M. (Systematic Theology)
74

Aplicacao dos isotopos naturais de Ra e do Th-234 como tracadores do carbono organico exportado para o estreito de bransfield, Antartica / Application of natural Ra isotopes and 234Th as tracers of organic carbon export in Bransfield Strait, Antartica

VIEIRA, LUCIA H. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:52:57Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:02Z (GMT). No. of bitstreams: 0 / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
75

Handling Tradeoffs between Performance and Query-Result Quality in Data Stream Processing

Ji, Yuanzhen 27 March 2018 (has links) (PDF)
Data streams in the form of potentially unbounded sequences of tuples arise naturally in a large variety of domains including finance markets, sensor networks, social media, and network traffic management. The increasing number of applications that require processing data streams with high throughput and low latency have promoted the development of data stream processing systems (DSPS). A DSPS processes data streams with continuous queries, which are issued once and return query results to users continuously as new tuples arrive. For stream-based applications, both the query-execution performance (in terms of, e.g., throughput and end-to-end latency) and the quality of produced query results (in terms of, e.g., accuracy and completeness) are important. However, a DSPS often needs to make tradeoffs between these two requirements, either because of the data imperfection within the streams, or because of the limited computation capacity of the DSPS itself. Performance versus result-quality tradeoffs caused by data imperfection are inevitable, because the quality of the incoming data is beyond the control of a DSPS, whereas tradeoffs caused by system limitations can be alleviated—even erased—by enhancing the DSPS itself. This dissertation seeks to advance the state of the art on handling the performance versus result-quality tradeoffs in data stream processing caused by the above two aspects of reasons. For tradeoffs caused by data imperfection, this dissertation focuses on the typical data-imperfection problem of stream disorder and proposes the concept of quality-driven disorder handling (QDDH). QDDH enables a DSPS to make flexible and user-configurable tradeoffs between the end-to-end latency and the query-result quality when dealing with stream disorder. Moreover, compared to existing disorder handling approaches, QDDH can significantly reduce the end-to-end latency, and at the same time provide users with desired query-result quality. In this dissertation, a generic buffer-based QDDH framework and three instantiations of the generic framework for distinct query types are presented. For tradeoffs caused by system limitations, this dissertation proposes a system-enhancement approach that combines the row-oriented and the column-oriented data layout and processing techniques in data stream processing to improve the throughput. To fully exploit the potential of such hybrid execution of continuous queries, a static, cost-based query optimizer is introduced. The optimizer works at the operator level and takes the unique property of execution plans of continuous queries—feasibility—into account.
76

Linguagem e interpretação na literatura agraria latina

Trevizam, Matheus 03 February 2006 (has links)
Orientador: Paulo Sergio de Vasconcellos / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Estudos da Linguagem / Made available in DSpace on 2018-08-05T20:08:04Z (GMT). No. of bitstreams: 1 Trevizam_Matheus_D.pdf: 1578970 bytes, checksum: 5efb6b093537be187dbbbb5fa29ba95e (MD5) Previous issue date: 2006 / Resumo: Neste trabalho, propomos a análise conjunta de três obras da literatura agrária latina (o De agri cultura de Catão Censor, o De re rustica de Varrão e as Geórgicas de Virgílio) do ponto de vista da construção do texto (elaboração genérico-literária e da linguagem), dos significados particulares das posturas de "ensinamento" e dos temas-outros (moral, religião, filosofia, política, mito...) sempre agregados à trama instrutiva. Além disso, propõem-se traduções divulgadoras do De agri cultura catoniano e do primeiro livro do De re rustica / Abstract: In this work, we propose the common analysis of three books of Latin agrarian literature (the De agri cultura of Cato, the De re rustica of Varro and Virgil's Georgics) from the viewpoint of textual construction (generic, literary and linguistic elaboration), of the particular meanings in teaching ways followed by each writer and of the additional themes (moral, religion, philosophy, politics, myth...) always included in the instructional whole. We also propose popularization translations of the De agri cultura and of the first book of the De re rustica / Doutorado / Doutor em Linguística
77

Aplicacao dos isotopos naturais de Ra e do Th-234 como tracadores do carbono organico exportado para o estreito de bransfield, Antartica / Application of natural Ra isotopes and 234Th as tracers of organic carbon export in Bransfield Strait, Antartica

VIEIRA, LUCIA H. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:52:57Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:02Z (GMT). No. of bitstreams: 0 / O Oceano Austral é o maior repositório dos oceanos, com concentrações elevadas de nutrientes e baixas de clorofila. A região tem papel fundamental para regular a transferência líquida de dióxido de carbono entre o oceano e a atmosfera, em parte devido à assimilação anual de CO2 pelo fitoplâncton, que resulta na exportação do carbono orgânico particulado (POC) para o oceano profundo. O elemento tório apresenta múltiplos isótopos que tem emergido como traçadores poderosos dos processos associados à transferência de material particulado nos oceanos. De todos os isótopos de Th, o 234Th (meia-vida de 24,1 d) tem sido foco de destaque e aplicação nos últimos anos. A produção do 234Th a partir do 238U, além do comportamento conservativo solúvel do 238U na água do mar, tornam fácil a caracterização das fontes de 234Th neste cenário. Além disso, a meiavida do 234Th é suficientemente curta para torná-lo sensível a mudanças a curto prazo (sazonais) que ocorrem na coluna dágua superficial dos oceanos, ou nas colunas dágua e de sedimentos nas regiões costeiras. Devido ao seu comportamento partículo-reativo, o 234Th é removido da água de duas formas, por decaimento ou pelo fluxo de material particulado. Desta forma, um modelo de balanço uni-dimensional no estado estacionário pode ser utilizado para estimar seu fluxo. Os isótopos naturais de Ra também tem sido amplamente empregados em estudos marinhos para traçar massas dágua e quantificar processos de mistura. Este trabalho apresenta os resultados de um projeto de pesquisa multidisciplinar que investigou a distribuição dos fluxos de carbono orgânico no Estreito de Bransfield com a finalidade de avaliar sua influência na remoção de CO2 da atmosfera local. As distribuições de macro-nutrientes, micro-nutrientes e clorofila-a foram utilizadas para examinar possíveis fontes e vias de transferência. Os isótopos de Ra foram aplicados como traçadores de massas dágua, enquanto o 234Th foi utilizado como traçador do fluxo particulado no oceano, uma vez que o afundamento deste material é o principal mecanismo de seqüestro de carbono no Oceano Austral. As amostras foram coletadas no período de 9 a 14 de Dezembro de 2007, a bordo do Navio de Apoio Oceanográfico Ary Rongel, da Marinha do Brasil. / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
78

Datování vývěrů radioaktivních minerálních vod v krkonošsko-jizerském krystaliniku metodou 230Th/234U / Dating of radioactive mineral springs of the Krkonoše-Jizera crystalline by 230Th/234U method

Fanta, Martin January 2016 (has links)
The isotopes 238 U, 234 U and 230 Th, as members of the uranium-radium decay chain, are fractionated in the environment by changes of geochemical conditions, and they can be used for dating of recent or past geochemical processes in the Quaternary. Samples of water with uranium and of water-activated solids were taken of radioactive mineral water springs at two study sites in the area of Krkonoše-Jizera crystalline complex: Svatý Vojtěch (St. Adalbert) in Horní Malá Úpa, and Bukový Pramen in the Těsný důl valley in Janské Lázně. Uranium was co-precipitated in field conditions with hydroxides of FeIII+ in 50-liter water samples of the radioactive springs. In the lab, uranium and thorium were separated from water precipitates, as well as from solid samples after their chemical decomposition, using chromatographic extraction agent UTEVA. All the three isotopes of interest emit alpha particles, and so their activities were measured by alpha spectrometry and expressed as 234 U/238 U and 230 Th/234 U ratios. As an internal standard, 232 U/228 Th was used. The resulting 234 U/238 U activity ratios of four water samples measured ranged from 1.0747 to 1.423. In twelve samples of solid phases activity ratios 234 U/238 U from 0.861 to 1.129 were determined. The 230 Th/234 U activity ratios form two distinct...
79

Uranium separations using extraction chromatography

Carter, Helen January 2000 (has links)
In the analysis of environmental samples for uranium and thorium pollutants and at natural levels for the dating of geological samples there was felt a need to develop better uranium and thorium separation procedures to replace the established anion exchange method used at AEA Technology plc. This was the first aim of the PhD research. Separation of uranium from thorium prior to measurement of the isotopes by alpha spectrometry was necessary due to the similar alpha energies of234U and 230Th. TRU and UTEVA extraction chromatography resins (EIChroM Industries) were investigated as potential replacements to the anion exchange separation method. The resins are claimed by EIChroM to offer the advantage of providing an actinide specific separation while reducing the separation time from 2 to 0.5 days; the volume of acidic waste produced by a factor of 3, therefore, the cost of analysis was reduced. A uranium and thorium separation procedure using the UTEVA extraction chromatography resin was developed. The uranium and thorium were sorbed by the UTEVA resin from 2M nitric acid. The thorium was then eluted from the resin with 5M hydrochloric acid and the uranium with 0.02M hydrochloric acid. The separation procedure was then evaluated using uraninite ore, coral, granite and lake sediment reference materials. The uranium and thorium concentrations and the 234U/238U and 23oTh/234U activity ratio values determined for the reference material were in good agreement with certified values. The presence of plutonium was found to interfere with the measurement of uranium and thorium by alpha spectrometry. This was due to the similar alpha energies of uranium, thorium and plutonium. The co-elution of plutonium with uranium and thorium from the UTEVA resin was prevented by the inclusion of a reduction step using iron (Il) sulphamate. The resulting plutonium (Ill) was not retained by the UTEVA column. The chemical recoveries for the procedure were similar to those for anion-exchange, but the extraction chromatography procedure provided a more rapid separation using less reagents.
80

Řízení o předběžné otázce v rámci evropského soudnictví / Preliminary reference procedure within the scope of European judicial system

Zvárová, Daniela January 2007 (has links)
The thesis deals with the preliminary reference procedure. There is outlined not only the characteristic of this procedure or its evolution, but also the interpretation of the term "court or tribunal of a Member State" or the Exceptions to the Duty to Refer. The following chapters are concerned with the statistical curiosities of the preliminary reference procedure or the ways of how to make this procedure more efficient. The last chapter is analysing the preliminary reference procedure from the Czech law's point of view. It deals with some Czech institutions as courts of the Member State, procedural aspects of this procedure or study of the Czech preliminary references. It also contains some cases of The Constitutional Court of the Czech Republic regarding with this procedure.

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