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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.
91

Statistical Inference for Heavy Tailed Time Series and Vectors

Tong, Zhigang January 2017 (has links)
In this thesis we deal with statistical inference related to extreme value phenomena. Specifically, if X is a random vector with values in d-dimensional space, our goal is to estimate moments of ψ(X) for a suitably chosen function ψ when the magnitude of X is big. We employ the powerful tool of regular variation for random variables, random vectors and time series to formally define the limiting quantities of interests and construct the estimators. We focus on three statistical estimation problems: (i) multivariate tail estimation for regularly varying random vectors, (ii) extremogram estimation for regularly varying time series, (iii) estimation of the expected shortfall given an extreme component under a conditional extreme value model. We establish asymptotic normality of estimators for each of the estimation problems. The theoretical findings are supported by simulation studies and the estimation procedures are applied to some financial data.
92

New statistical models for extreme values

Eljabri, Sumaya Saleh M. January 2013 (has links)
Extreme value theory (EVT) has wide applicability in several areas like hydrology, engineering, science and finance. Across the world, we can see the disruptive effects of flooding, due to heavy rains or storms. Many countries in the world are suffering from natural disasters like heavy rains, storms, floods, and also higher temperatures leading to desertification. One of the best known extraordinary natural disasters is the 1931 Huang He flood, which led to around 4 millions deaths in China; these were a series of floods between Jul and Nov in 1931 in the Huang He river.Several publications are focused on how to find the best model for these events, and to predict the behaviour of these events. Normal, log-normal, Gumbel, Weibull, Pearson type, 4-parameter Kappa, Wakeby and GEV distributions are presented as statistical models for extreme events. However, GEV and GP distributions seem to be the most widely used models for extreme events. In spite of that, these models have been misused as models for extreme values in many areas.The aim of this dissertation is to create new modifications of univariate extreme value models.The modifications developed in this dissertation are divided into two parts: in the first part, we make generalisations of GEV and GP, referred to as the Kumaraswamy GEV and Kumaraswamy GP distributions. The major benefit of these models is their ability to fit the skewed data better than other models. The other idea in this study comes from Chen, which is presented in Proceedings of the International Conference on Computational Intelligence and Software Engineering, pp. 1-4. However, the cumulative and probability density functions for this distribution do not appear to be valid functions. The correction of this model is presented in chapter 6.The major problem in extreme event models is the ability of the model to fit tails of data. In chapter 7, the idea of the Chen model with the correction is combined with the GEV distribution to introduce a new model for extreme values referred to as new extreme value (NEV) distribution. It seems to be more flexible than the GEV distribution.
93

Textová a obsahová analýza jazyka současné krajně pravicové a krajně levicové mládeže / Textual Content Analysis of the Contemprorary Extreme Right and Extreme Left Youth Organization

Brejchová, Pavla January 2011 (has links)
This paper is dealing with a textual content analysis of extreme right and extreme left youth organizations. A methodological framework for the analysis is described in chapter one. A special attention is devoting to the content analysis method. Ideological and theoretical placement of extreme right and extreme left are discussed in chapter two. This chapter is also dealing with the particular associations (KSM, SMKČ, DM). The content analysis ant its results are presented in chapter three.
94

Perceived growth following endeavors to isolated, confined, and extreme environments: salutogenesis in the aftermath of Antarctic expeditions

Nicoll, Patrick 08 October 2021 (has links)
The environmental and psychosocial adversity inherent in remote polar locales has historically been framed in pathological terms. However, a burgeoning body of evidence suggests that stressful conditions across isolated, confined, and extreme (ICE) environments may elicit positive growth outcomes as well. The purpose of this cross-sectional, retrospective study was to assess the incidence and correlates of PostExpedition Growth (PEG) in returned Antarctic expeditioners. The prevalence of five specific personal growth indicators – ‘new opportunities,’ ‘relating to others,’ ‘personal strength,’ ‘spiritual change,’ and ‘appreciation of life’ – along with individual and group variables that have been associated with growth in trauma-exposed populations (i.e., coping, mindfulness, personality traits, personal value priorities, adverse childhood experiences, and expedition/experience specific variables) were examined using a mixed methods approach. Quantitative results indicate a moderate, positive association between proactive coping and appreciation of life, as well as between universalism (i.e., a sense of harmony or oneness with humanity and the natural world), new possibilities, and appreciation of life. Qualitative findings provide a more nuanced understanding of the five dimensions of PEG and underscore the emergence of a sixth dimension, an enhanced relationship with nature. Further research is needed to illuminate knowledge gaps in ICE environment research, and to help identify potential countermeasures for individuals and groups faced with comparable adversity factors in their immediate environments (i.e., within the current context of COVID-19). A deeper understanding of PEG in ICE environments – as well as promotive factors that strengthen positive outcomes – will serve to inform the development of countermeasures to mitigate health and wellbeing risks following exposure to isolation and confinement in extreme environments. / Graduate / 2022-09-29
95

IMPROVING EXTREME PRECIPITATION ESTIMATES CONSIDERING REGIONAL FREQUENCY ANALYSIS / 地域頻度解析を考慮した極端降水推定値の精度向上に関する研究

Nor Eliza Binti Alias 24 September 2014 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18562号 / 工博第3923号 / 新制||工||1603(附属図書館) / 31462 / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 寶 馨, 教授 中北 英一, 教授 田中 茂信 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
96

Derivace v aplikačních úlohách - sbírka řešených příkladů. / Derivative in apllied problems - a digest of solved examples.

ZACHAROVÁ, Jana January 2014 (has links)
The main goal of my diploma work on the topic "Derivative in apllied problems a digest of solved examples" is to create a set of solved exercises that somehow use calculus during solving. The collection contains 43 solved practical problems relating to calculus of one or two variables. This collection intends to serve as a training aid for students of middle or high schools. For a better overview individual tasks are sorted by appropriate fields of science (mathematical, biological, physical, economic).
97

Komparace politických a kulturních aktivit extrémně pravicové scény v ČR a SRN v 90. letech 20. století / Comparison of political and cultural activities of the extreme right in the Czech Republic and Germany during 90's in the 20th century

Pardubská, Martina January 2016 (has links)
Master thesis "The comparison of political and cultural activities of the extreme right in the Czech Republic and Germany during 90's in the 20th century" is firstly defining the terms related to study of the extreme right. Secondly, the thesis is analyzing success of German and Czech extreme right wing parties in the elections, then establishing and forms of membership in the extreme right organizations, making demonstrations, protest events and violent acts with extreme right context which are organized by supporters of the extreme right thoughts. Thirdly, the thesis is focusing on cultural activities, such as live music events with extreme right music artists, with outlining the lyrics of these Czech and German artists. Finally, comparative analysis is describing the form and frequency of all political and cultural activities. Conclusion of the thesis is that forms of the extreme right in the Czech Republic and Germany in the 90's were very similar, however in Germany these activities were more regular and more brutal. KEYWORDS Extreme right wing, ultra - right, neo - Nazism, extreme right wing parties, extreme right organizations, skinheads.
98

High-pressure studies of ammonia hydrates

Wilson, Craig W. January 2014 (has links)
Ammonia and water are major components of many planetary bodies, from comets and icy moons such as Saturn's Titan to the interiors of the planets Neptune and Uranus. Under a range of high pressures and/or low temperatures known to occur in these planetary bodies, ammonia and water form a series of compounds known as ammonia hydrates. Ammonia and water form three stoichiometric compounds, ammonia hemihydrate, ammonia monohydrate and ammonia dihydrate, which have ammonia-to-water ratios of 2:1, 1:1 and 1:2 respectively. Therefore a good understanding of the three stable ammonia hydrates is required for modelling the interiors of these bodies. Additionally, the ammonia hydrates are the simplest systems to incorporate mixed (N-H O and O-H N) hydrogen bonds. Such bonds are important biochemically, and along with O-H O H-bonds, mixed H-bonds are responsible for the second-order structure of DNA, and they are also responsible for the proton transfer reactions in enzymic processes. The understanding of these bonds and processes rests on the knowledge of the relationship between bond strength and geometry, and the ammonia hydrates provide a rich range of geometries against which models of such mixed H-bonds can be tested. X-ray and neutron diffraction techniques have been used to investigate the behaviour of the ammonia-water complex and further the understanding of this system. This includes solving the structure of a phase which was previously thought to be an ammonia monohydrate phase, but has been shown here to be a mixture of an ammonia hemihydrate phase and Ice VII. In addition to this, x-ray and neutron diffraction experiments have been performed to explore how this phase behaves under changing pressure and temperature conditions, and what other implications that this has on the ammonia-water system. It has been found that ammonia hemihydrate can also form a structural phase observed to form in both ammonia monohydrate and ammonia dihydrate within the same pressure and temperature regime, which opens the possibility of a solid solution existing between all three stoichiometric ammonia hydrates.
99

Improvements to the computational pipeline in crystal plasticity estimates of high cycle fatigue of microstructures

Kern, Paul Calvin 27 May 2016 (has links)
The objective of this work is to provide various improvements to the modeling and uncertainty quantification of fatigue lives of materials as understood via simulation of crystal plasticity models applied to synthetically reconstructed microstructures. A computational framework has been developed to automate standardized analysis of crystal plasticity models in the high cycle fatigue regime. This framework incorporates synthetic microstructure generation, simulation preparation, execution and post-processing to analysis statistical distributions related to fatigue properties. Additionally, an improved crack nucleation and propagation approach has been applied to Al 7075-T6 to improve predictive capabilities of the crystal plasticity model for fatigue in various loading regimes. Finally, sensitivities of fatigue response to simulation and synthetic microstructure properties have been explored to provide future guidance for the study of fatigue quantification based on crystal plasticity models.
100

Assessment of oxidative stress in athletes during extreme endurance exercise using deuterium-labeled vitamin E

Mastaloudis, Angela 23 August 2000 (has links)
To determine whether extreme endurance exercise induces lipid peroxidation, we studied 14 athletes (5 females: 9 males) during a 50 km ultramarathon (trial 1) and during a sedentary protocol (trial 2) one month later. At dinner the evening before the race (or sedentary trial), subjects consumed vitamin E labeled with stable isotopes (75 mg each d₃-RRR and d₆-all rac-α-tocopheryl acetates). Blood samples were taken at baseline, 30 minutes pre-race, mid-race, post-race, 1 h post-race, 24 h post-race, and at corresponding times for each individual during trial 2. During the sedentary day of trial 2, subjects consumed the same amounts of race day foods, including ergogenic aids, that they had consumed in trial 1; vitamin E intakes were 77 ± 40 mg, and vitamin C 406 ± 169 mg. All 14 subjects completed the race; average time to completion was 390 ± 67 minutes. Plasma F₂-isoprostanes (F₂-I), labeled and unlabeled α-tocopherol, and ascorbic acid (AA) were measured. F₂-I increased from 76 ± 24 pg/ml pg/ml at pre-race to 117.4 ± 38.0 pg/ml (p<0.0008) at mid-race to 130 ± 54 pg/ml (p<0.0001) at post-race, then returned to baseline at 24 hours post-race; F₂-I were unchanged during trial 2. Deuterated d₃ α-tocopheryl (d₃ α-Toc) disappearance rates were faster (2.8x10⁻⁴ ± 0.5x10⁻⁴) during the race compared to the sedentary trial (2.3x10⁻⁴ ± 0.6x10⁻⁴; p < 0.03). Plasma AA increased from 75.2 ± 11.2 μM at pre-race to 157.7 ± 36.2 μM at race end (p<0.0001) and decreased to below baseline concentrations at 24 h post-race (40.4 ± 5.2 μM p<0.0001). AA levels also increased during trial 2. Despite increased plasma AA, F2-I increased during exercise, but not during the sedentary period. Additionally, vitamin E disappeared faster during the run compared to the sedentary protocol. Thus, extreme endurance exercise results in the generation of lipid peroxidation and increased vitamin E utilization. / Graduation date: 2001

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