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Prorůstání krajně levicových a krajně pravicových skupin s tvrdým jádrem fanoušků fotbalových klubů Bohemians 1905, Slavia Praha a Sparta Praha / Penetration of extreme left and extreme right-wing groups with hard core fans of football clubs Bohemians 1905, Slavia Prague and Sparta PragueDytrych, Martin January 2014 (has links)
The Diploma thesis focuses on examination of real interconnection between political extremism and hardcore fans of Bohemians 1905, Slavie Praha and Sparta Praha. The research itself is therefore concentrated primarily on people associated with political extremism and their relation to groups of ultras and hooligans and furthermore their influence on these groups. The theoretical part of the thesis introduces theory of political extremism, typology groups of people attending football games, their development and the reasons of their politicization. The analytical part elaborates particulary the different Prague football clubs and their fans. Part of the data is applied from fourteen half-structured interviews with ultras and hooligans representatives of these clubs. The goal of the thesis is to clarify the real scale of interconnection between political activists and hardcore fans on the one hand, and on the other hand to point out and explain the attempts of political extremist to penetrace into this enviroment and assess the degree of their success.
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Ionospheric response during low and high solar activityVaishnav, Rajesh, Jacobi, Ch., Berdermann, J., Schmölter, E., Codrescu, M. 24 September 2018 (has links)
We analyse solar extreme ultraviolet (EUV) irradiance observed by the Solar EUV Experiment (SEE) onboard the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite, and solar proxies (the F10.7 index, and Mg-II index), and compare their variability with the one of the global mean Total Electron Content (GTEC). Cross-wavelet analysis confirms the joint 27 days periodicity in GTEC and solar proxies. We focus on a comparison for solar minimum (2007-2009) and maximum (2013-2015) and find significant differences in the correlation during low and high solar activity years. GTEC is delayed by
approximately 1-2 days in comparison to solar proxies during both low and high solar activity at the 27 days solar rotation period. To investigate the dynamics of the delay process, Coupled Thermosphere Ionosphere Plasmasphere electrodynamics model simulations have been performed for low and high solar activity conditions. Preliminary results using cross correlation analysis show an ionospheric delay of 1 day in GTEC with respect to the F10.7 index during low and high solar activity. / Wir analysieren vom Solar Extreme Ultraviolet Experiment (SEE) an Bord des Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) Satelliten gemessene solare EUV-Irradianzen, solare Proxies (den F10.7-Index und denMg-II-Index), und vergleichen deren Variabilität mit derjenigen des global gemittelten Gesamtelektronengehalts (GTEC). Kreuzwaveletanalysen bestätigen eine gemeinsame Variabilität im Periodenbereich der solaren Rotation (27 Tage). Wir vergleichen insbesondere den Zusammenhang während des solaren Minimums (2007- 2009) und Maximums (2013-2015), wobei signifikante Unterschiede der Korrelation zwischen solaren und ionosphärischen Parametern auftreten. Es tritt eine Verzögerung der Maxima und Minima von GTEC gegenüber denjenigen der solaren Proxies von
einem Tag sowohl im solaren Minimum als auch im solaren Maximum auf.
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XFM: An Incremental Methodology for Developing Formal ModelsSuhaib, Syed Mohammed 13 May 2004 (has links)
We present a methodology of an agile formal method named eXtreme Formal Modeling (XFM) recently developed by us, based on Extreme Programming concepts to construct abstract models from a natural language specification of a complex system. In particular, we focus on Prescriptive Formal Models (PFMs) that capture the specification of the system under design in a mathematically precise manner. Such models can be used as golden reference models for formal verification, test generation, etc. This methodology for incrementally building PFMs work by adding user stories (expressed as LTL formulae) gleaned from the natural language specifications, one by one, into the model. XFM builds the models, retaining correctness with respect to incrementally added properties by regressively model checking all the LTL properties captured theretofore in the model. We illustrate XFM with a graded set of examples including a traffic light controller, a DLX pipeline and a Smart Building control system. To make the regressive model checking steps feasible with current model checking tools, we need to keep the model size increments under control. We therefore analyze the effects of ordering LTL properties in XFM. We compare three different property-ordering methodologies: 'arbitrary ordering', 'property based ordering' and 'predicate based ordering'. We experiment on the models of the ISA bus monitor and the arbitration phase of the Pentium Pro bus. We experimentally show and mathematically reason that predicate based ordering is the best among these orderings. Finally, we present a GUI based toolbox for users to build PFMs using XFM. / Master of Science
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Development Of Methods For Structural Reliability Analysis Using Design And Analysis Of Computer Experiments And Data Based Extreme Value AnalysisPanda, Satya Swaroop 06 1900 (has links)
The work reported in this thesis is in the area of computational modeling of reliability of engineering structures. The emphasis of the study is on developing methods that are suitable for analysis of large-scale structures such as aircraft structure components. This class of problems continues to offer challenges to an analyst with the most difficult aspect of the analysis being the treatment of nonlinearity in the structural behavior, non-Gaussian nature of uncertainties and quantification of low levels of probability of failure (of the order of 10-5 or less), requiring significant computational effort. The present study covers static/ dynamic behavior, Gaussian/ non-Gaussian models of uncertainties, and (or) linear/ nonlinear structures. The novel elements in the study consist of two components:
• application of modeling tools that already exists in the area of design and analysis of computer experiments, and
. • application of data based extreme value analysis procedures that are available in the statistics literature.
The first component of the work provides opportunity to combine space filling sampling strategies (which have promise for reducing variance of estimation) with kriging based modeling in reliability studies-an opportunity that has not been explored in the existing literature. The second component of the work exploits the virtues of limiting behavior of extremes of sequence of random variables with Monte Carlo simulations of structural response-a strategy for reliability modeling that has not been explored in the existing literature. The hope here is that failure events with probabilities of the order of 10-5 or less could be investigated with relatively less number of Monte Carlo runs. The study also brings out the issues related to combining the above sources of existing knowledge with finite element modeling of engineering structures, thereby leading to newer tools for structural reliability analysis.
The thesis is organized into four chapters. The first chapter provides a review of literature that covers methods of reliability analysis and also the background literature on design and analysis of computer experiments and extreme value analysis.
The problem of reliability analysis of randomly parametered, linear (or) nonlinear structures subjected to static and (or) dynamic loads is considered in Chapter 2. A deterministic finite element model for the structure to analyze sample realization of the structure is assumed to be available. The reliability analysis is carried out within the framework of response surface methods, which involves the construction of surrogate models for performance functions to be employed in reliability calculations. These surrogate models serve as models of models, and hence termed as meta-models, for structural behavior in the neighborhood of design point. This construction, in the present study, has involved combining space filling optimal Latin hypercube sampling and kriging models. Illustrative examples on numerical prediction of reliability of a ten-bay truss and a W-seal in an aircraft structure are presented. Limited Monte Carlo simulations are used to validate the approximate procedures developed.
The reliability of nonlinear vibrating systems under stochastic excitations is investigated in Chapter 3 using a two-stage Monte Carlo simulation strategy. Systems subjected to Gaussian random excitation are considered for the study. It is assumed that the probability distribution of the maximum response in the steady state belongs to the basin of attraction of one of the classical asymptotic extreme value distributions. The first stage of the solution strategy consists of an objective selection of the form of the extreme value distribution based on hypothesis tests, and the next involves the estimation of parameters of the relevant extreme value distribution. Both these steps are implemented using data from limited Monte Carlo simulations of the system response. The proposed procedure is illustrated with examples of linear/nonlinear single-degree and multi-degree of freedom systems driven by random excitations. The predictions from the proposed method are compared with results from large-scale Monte Carlo simulations and also with classical analytical results, when available, from theory of out-crossing statistics. The method is further extended to cover reliability analysis of nonlinear dynamical systems with randomly varying system parameters. Here the methods of meta-modeling developed in Chapter 2 are extended to develop response surface models for parameters of underlying extreme value distributions. Numerical examples presented cover a host of low-dimensional dynamical systems and also the analysis of a wind turbine structure subjected to turbulent wind loads and undergoing large amplitude oscillations.
A summary of contributions made along with a few suggestions for further research is presented in Chapter 4.
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Mnohorozměrná teorie extrémních hodnot / Multivariate extreme value theoryŠiklová, Renata January 2013 (has links)
In this thesis we will elaborate on multivariate extreme value modelling, re- lated practical and theoretical aspects. We will mainly focus on the dependence models, the extreme value copulas in particular. Extreme value copulas effec- tively unify the univariate extreme value theory and the copula framework itself in a single view. We familiarize ourselves with both of them in the first two chapters. Those chapters present generalized extreme value distribution, gen- eralized Pareto distribution and Archimedean copulas, that are suitable for the multivariate maxima and the threshold exceedances description. These two top- ics will be addressed in the third chapter in detail. Taking into consideration rather practical focus of this thesis, we examine the methods of data analysis extensively. Furthermore, we will employ these methods in a comprehensive case study, that will aim to reveal the importance of extreme value theory application in the Catastrophe Insurance. 1
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Teorie extrémních hodnot v aktuárských vědách / Extreme Value Theory in Actuarial SciencesJamáriková, Zuzana January 2013 (has links)
This thesis is focused on the models based on extreme value theory and their practical applications. Specifically are described the block maxima models and the models based on threshold exceedances. Both of these methods are described in thesis theoretically. Apart from theoretical description there are also practical calculations based on simulated or real data. The applications of block maxima models are focused on choice of block size, suitability of the models for specific data and possibilities of extreme data analysis. The applications of models based on threshold exceedances are focused on choice of threshold and on suitability of the models. There is an example of the model used for calculations of reinsurance premium for extreme claims in the case of nonproportional reinsurance.
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Modelování operačního rizika / Operational risk modellingMináriková, Eva January 2013 (has links)
In the present thesis we will firstly familiarize ourselves with the term of operational risk, it's definition presented in the directives Basel II and Solvency II, and afterwards with the methods of calculation Capital Requirements for Operational Risk, set by these directives. In the second part of the thesis we will concentrate on the methods of modelling operational loss data. We will introduce the Extreme Value Theory which describes possible approaches to modelling data with significant values that occur infrequently; the typical characteristic of operational risk data. We will mainly focus on the model for threshold exceedances which utilizes Generalized Pareto Distribution to model the distribution of those excesses. The teoretical knowledge of this theory and the appropriate modelling will be applied on simulated loss data. Finally we will test the ability of presented methods to model loss data distributions.
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A distribuição normal-valor extremo generalizado para a modelagem de dados limitados no intervalo unitá¡rio (0,1) / The normal-generalized extreme value distribution for the modeling of data restricted in the unit interval (0,1)Benites, Yury Rojas 28 June 2019 (has links)
Neste trabalho é introduzido um novo modelo estatístico para modelar dados limitados no intervalo continuo (0;1). O modelo proposto é construído sob uma transformação de variáveis, onde a variável transformada é resultado da combinação de uma variável com distribuição normal padrão e a função de distribuição acumulada da distribuição valor extremo generalizado. Para o novo modelo são estudadas suas propriedades estruturais. A nova família é estendida para modelos de regressão, onde o modelo é reparametrizado na mediana da variável resposta e este conjuntamente com o parâmetro de dispersão são relacionados com covariáveis através de uma função de ligação. Procedimentos inferênciais são desenvolvidos desde uma perspectiva clássica e bayesiana. A inferência clássica baseia-se na teoria de máxima verossimilhança e a inferência bayesiana no método de Monte Carlo via cadeias de Markov. Além disso estudos de simulação foram realizados para avaliar o desempenho das estimativas clássicas e bayesianas dos parâmetros do modelo. Finalmente um conjunto de dados de câncer colorretal é considerado para mostrar a aplicabilidade do modelo. / In this research a new statistical model is introduced to model data restricted in the continuous interval (0;1). The proposed model is constructed under a transformation of variables, in which the transformed variable is the result of the combination of a variable with standard normal distribution and the cumulative distribution function of the generalized extreme value distribution. For the new model its structural properties are studied. The new family is extended to regression models, in which the model is reparametrized in the median of the response variable and together with the dispersion parameter are related to covariables through a link function. Inferential procedures are developed from a classical and Bayesian perspective. The classical inference is based on the theory of maximum likelihood, and the Bayesian inference is based on the Markov chain Monte Carlo method. In addition, simulation studies were performed to evaluate the performance of the classical and Bayesian estimates of the model parameters. Finally a set of colorectal cancer data is considered to show the applicability of the model
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Modelling heavy rainfall over time and spaceKhuluse, Sibusisiwe Audrey 06 June 2011 (has links)
Extreme Value Theory nds application in problems concerning low probability but high
consequence events. In hydrology the study of heavy rainfall is important in regional
ood
risk assessment. In particular, the N-year return level is a key output of an extreme value
analysis, hence care needs to be taken to ensure that the model is accurate and that the
level of imprecision in the parameter estimates is made explicit.
Rainfall is a process that evolves over time and space. Therefore, it is anticipated that
at extreme levels the process would continue to show temporal and spatial correlation. In
this study interest is in whether any trends in heavy rainfall can be detected for the Western
Cape. The focus is on obtaining the 50-year daily winter rainfall return level and investigating
whether this quantity is homogenous over the study area. The study is carried out in
two stages.
In the rst stage, the point process approach to extreme value theory is applied to arrive
at the return level estimates at each of the fteen sites. Stationarity is assumed for the
series at each station, thus an issue to deal with is that of short-range temporal correlation of
threshold exceedances. The proportion of exceedances is found to be smaller (approximately
0.01) for stations towards the east such as Jonkersberg, Plettenbergbay and Tygerhoek.
This can be attributed to rainfall values being mostly low, with few instances where large
amounts of rainfall were observed. Looking at the parameters of the point process extreme
value model, the location parameter estimate appears stable over the region in contrast to
the scale parameter estimate which shows an increase towards in a south easterly direction.
While the model is shown to t exceedances at each station adequately, the degree of uncertainty
is large for stations such as Tygerhoek, where the maximum observed rainfall value is
approximately twice as large as the high rainfall values. This situation was also observed at
other stations and in such cases removal of these high rainfall values was avoided to minimize
the risk of obtaining inaccurate return level estimates. The key result is an N-year rainfall
return level estimate at each site. Interest is in mapping an estimate of the 50-year daily
winter rainfall return level, however to evaluate the adequacy of the model at each site the
25-year return level is considered since a 25 year return period is well within the range of the
observed data. The 25-year daily winter rainfall return level estimate for Ladismith is the
smallest at 22:42 mm. This can be attributed to the station's generally low observed winter
rainfall values. In contrast, the return level estimate for Tygerhoek is high, almost six times
larger than that of Ladismith at 119:16 mm. Visually design values show di erences between
sites, therefore it is of interest to investigate whether these di erences can be modelled.
The second stage is the geostatistical analysis of the 50-year 24-hour rainfall return level The aim here is to quantify the degree of spatial variation in the 50-year 24-hour rainfall
return level estimates and to use that association to predict values at unobserved sites within
the study region. A tool for quantifying spatial variation is the variogram model. Estimation
of the parameters of this model require a su ciently large sample, which is a challenge in
this study since there is only fteen stations and therefore only fteen observations for the
geostatistical analysis. To address this challenge, observations are expanded in space and
time and then standardized and to create a larger pool of data from which the variogram is
estimated. The obtained estimates are used in ordinary and universal kriging to derive the
50-year 24-hour winter rainfall return level maps. It is shown that 50-year daily winter design
rainfall over most of the Western Cape lies between 40 mm and 80 mm, but rises sharply as
one moves towards the east coast of the region. This is largely due to the in
uence of large
design values obtained for Tygerhoek. In ordinary kriging prediction uncertainty is lowest
around observed values and is large if the distance from these points increases. Overall, prediction
uncertainty maps show that ordinary kriging performs better than universal kriging
where a linear regional trend in design values is included.
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Determinism and predictability in extreme event systemsBirkholz, Simon 12 May 2016 (has links)
In den vergangenen Jahrzehnten wurden extreme Ereignisse, die nicht durch Gauß-Verteilungen beschrieben werden können, in einer Vielzahl an physikalischen Systemen beobachtet. Während statistische Methoden eine zuverlässige Identifikation von extremen Ereignissen ermöglichen, ist deren Entstehungsmechanismus nicht vollständig geklärt. Das Auftreten von extremen Ereignissen ist nicht vollkommen verstanden, da sie nur selten beobachtet werden können und häufig unter schwer reproduzierbaren Bedingungen auftreten. Deshalb ist es erstrebenswert Experimente zu entwickeln, die eine einfache Beobachtung von extremen Ereignissen erlauben. In dieser Dissertation werden extreme Ereignisse untersucht, die bei Multi-Filamentation von Femtosekundenlaserimpulsen entstehen. In den Experimenten, die in dieser Dissertation vorgestellt werden, werden Multi-Filamente durch Hochgeschwindigkeitskameras analysiert. Die Untersuchung der raum-zeitlichen Dynamik der Multi-Filamente zeigt eine L-förmige Wahrscheinlichkeitsverteilung, Diese Beobachtung impliziert das Auftreten von extremen Ereignissen. Lineare Analyse liefert Hinweise auf die physikalischen Prozesse, die zur Entstehung der extremen Ereignisse führen und nicht-lineare Zeitreihen-Analyse charakterisiert die Dynamik des Systems. Die Analyse der Multi-Filamente wird außerdem auf extreme Ereignisse in Wellen-Messungen und optische Superkontinua angewandt. Die durchgeführten Analysen zeigen Unterschiede in den physikalischen Prozessen, die zur Entstehung von extremen Ereignissen führen. Extreme Ereignisse in optischen Fasern werden durch stochastische Fluktuationen von verstärktem Quantenrauschen dominiert. In Multi-Filamenten und Ozeanwellen resultieren extreme Ereignisse dagegen aus klassischer mechanischer Turbulenz, was deren Vorhersagbarkeit impliziert. In dieser Arbeit wird anhand der von Multi-Filament-Zeitreihen die Vorhersagbarkeit in einem kurzen Zeitfenster vor Auftreten des extremen Ereignisses bewiesen. / In the last decades, extreme events, i.e., high-magnitude phenomena that cannot be described within the realm of Gaussian probability distributions have been observed in a multitude of physical systems. While statistical methods allow for a reliable identification of extreme event systems, the underlying mechanism behind extreme events is not understood. Extreme events are not well understood due to their rare occurrence and their onset under conditions that are difficult to reproduce. Thus, it is desirable to identify extreme event scenarios that can serve as a test bed. Optical systems exhibiting extreme events have been discovered to be ideal for such tests, and it is now desired to find more different examples to improve the understanding of extreme events. In this thesis, multifilamentation formed by femtosecond laser pulses is analyzed. Observation of the spatio-temporal dynamics of multifilamentation shows a heavy-tailed fluence probability distribution. This finding implies the onset of extreme events during multifilamentation. Linear analysis gives hints on the processes that drive the formation of extreme events. The multifilaments are also analyzed by nonlinear time series analysis, which provides information on determinism and chaos in the system. The analysis of the multifilament s is compared to an analysis of extreme event time series from ocean wave measurements and the supercontinuum output of an optical fiber. The analysis performed in this work shows fundamental differences in the extreme event mechnaism. While the extreme events in the optical fiber system are ruled by the stochastic changes of amplified quantum noise, in the multifilament and the ocean system extreme events appear as a result of the classical mechanical process of turbulence. This implies the predictability of extreme events. In this work, the predictability of extreme events is proven to be possible in a brief time window before the onset of the extreme event.
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