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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.
161

Abschätzungen der Konvergenzgeschwindigkeit zur Normalverteilung unter Voraussetzung einseitiger Momente (Teil 2)

Paditz, Ludwig 27 May 2013 (has links) (PDF)
Der Beitrag unterteilt sich in zwei Teile: Teil 1 (vgl. Informationen/07; 1976,05) und Teil 2 (cp. Informationen/07; 1976,06). Teil 1 enthält eine Einleitung und Grenzwertsätze für unabhängige und identisch verteilte Zufallsgrößen und die Übertragung der betrachteten Grenzwertsätze auf den Fall der Existenz einseitiger Momente. Teil 2 enthält Grenzwertsätze für mittlere Abweichungen für Summen unabhängiger nichtidentisch verteilter Zufallsgrößen (Serienschema) und eine Diskussion der erhaltenen Ergebnisse und schließlich einige Literaturangaben. Sei F_n(x) die Verteilungsfunktion der Summe X_1+X_2+...+X_n, wobei X_1, X_2, ...,X_n unabhängige und identisch verteilte Zufallsgrößen mit Erwartungswert 0 und Streuung 1 und endlichen absoluten Momenten c_m, m>2, sind, und sei Phi die standardisierte Normalverteilungsfunktion. Es werden absolute Konstanten L_i derart berechnet, dass wir Fehlerabschätzungen im unleichmäßigen zentralen Grenzwertsätzen in verschiedenen Fällen angeben können, wobei sich der Index i in L_i auf folgende fünf Fälle bezieht: kleine x, mittlere Abweichungen für x, große Abweichungen für x, kleine n und große n. Im Fall der Existenz einseitiger Momente werden obere Schanken für 1-F_n(x) angegeben für x>D_m*n^(1/2)*ln(n) bzw. x>D_m*n^(1/2)*(ln(n))^(1/2), womit Ergebnisse von S.V.NAGAEV(1965) präzisiert werden. Der Beitrag unterteilt sich in zwei Teile: Teil 1 (vgl. Informationen/07; 1976,05) und Teil 2 (cp. Informationen/07; 1976,06). Teil 1 enthält eine Einleitung und Grenzwertsätze für unabhängige und identisch verteilte Zufallsgrößen und die Übertragung der betrachteten Grenzwertsätze auf den Fall der Existenz einseitiger Momente. Teil 2 enthält Grenzwertsätze für mittlere Abweichungen für Summen unabhängiger nichtidentisch verteilter Zufallsgrößen (Serienschema) und eine Diskussion der erhaltenen Ergebnisse und schließlich einige Literaturangaben. Sei F_n(x) die Verteilungsfunktion der Summe X_1+X_2+...+X_n, wobei X_1, X_2, ...,X_n unabhängige und identisch verteilte Zufallsgrößen mit Erwartungswert 0 und Streuung 1 und endlichen absoluten Momenten c_m, m>2, sind, und sei Phi die standardisierte Normalverteilungsfunktion. Es werden absolute Konstanten L_i derart berechnet, dass wir Fehlerabschätzungen im unleichmäßigen zentralen Grenzwertsätzen in verschiedenen Fällen angeben können, wobei sich der Index i in L_i auf folgende fünf Fälle bezieht: kleine x, mittlere Abweichungen für x, große Abweichungen für x, kleine n und große n. Im Fall der Existenz einseitiger Momente werden obere Schanken für 1-F_n(x) angegeben für x>D_m*n^(1/2)*ln(n) bzw. x>D_m*n^(1/2)*(ln(n))^(1/2), womit Ergebnisse von S.V.NAGAEV(1965) präzisiert werden. / The paper is divided in two parts: part 1 (cp. Informationen/07; 1976,05) and part 2 (cp. Informationen/07; 1976,06). Part 1 contains an introduction and limit theorems for iid random variables and the transfer of the considered limit theorems to the case of the existence of onesided moments. Part 2 contains limit theorems of moderate deviations for sums of series of non iid random variables and a discussion of all obtained results in part 1 and 2 and finally some references. Let F_n(x) be the cdf of X_1+X_2+...+X_n, where X_1, X_2, ...,X_n are iid random variables with mean 0 and variance 1 and with m-th absolute moment c_m, m>2, and Phi the cdf of the unit normal law. Explicit universal constants L_i are computed such that we have an error estimate in the nonuniform central limit theorem with the L_i, where i corresponds to the five cases considered: small x, moderate deviations for x, large deviations for x, small n , large n. Additional upper bounds for 1-F_n(x) are obtained if the one-sided moments of order m, m>2, are finite and if x>D_m*n^(1/2)*ln(n) and x>D_m*n^(1/2)*(ln(n))^(1/2) respectively improving results by S.V.NAGAEV (1965).
162

Über mittlere Abweichungen

Paditz, Ludwig 27 May 2013 (has links) (PDF)
In diesem Artikel werden notwendige und hinreichende Bedingungen für die Gültigkeit von Grenzwertsätzen für mittlere Abweichungen untersucht. In der Terminilogie von J.V.LINNIK (1971) werden die x-Bereiche für mittlere Abweichungen gewöhnlich als "sehr enge" Zonen der integralen normalen Anziehung bezeichnet. Darüber hinaus werden die Restglieder untersucht, die in den asymptotischen Beziehungen auftreten. Die Ordnung der Konvergenzgeschwindigkeit wird angegeben. Frühere Ergebnisse einiger Autoren werden verallgemeinert. Abschließend werden einige Literaturhinweise angegeben. / In this paper we study necessary and sufficient conditions for the validity of limit theorems on moderate deviations. Usually x-zones for moderate deviations are called in the terminilogy by YU.V.LINNIK (1971) "very narrow" zones of integral normal attraction. Moreover we analyse the remainder term appearing in the asymptotic relations. Informations on the order of the rate of convergence are given. Earlier results by several authors are generalized. Finally some references are given.
163

Limit theorems for a one-dimensional system with random switchings

Hurth, Tobias 15 November 2010 (has links)
We consider a simple one-dimensional random dynamical system with two driving vector fields and random switchings between them. We show that this system satisfies a one force - one solution principle and compute its unique invariant density explicitly. We study the limiting behavior of the invariant density as the switching rate approaches zero and infinity and derive analogues of classical probabilistic results such as the central limit theorem and large deviations principle.
164

Das parabolische Anderson-Modell mit Be- und Entschleunigung

Schmidt, Sylvia 24 January 2011 (has links) (PDF)
We describe the large-time moment asymptotics for the parabolic Anderson model where the speed of the diffusion is coupled with time, inducing an acceleration or deceleration. We find a lower critical scale, below which the mass flow gets stuck. On this scale, a new interesting variational problem arises in the description of the asymptotics. Furthermore, we find an upper critical scale above which the potential enters the asymptotics only via some average, but not via its extreme values. We make out altogether five phases, three of which can be described by results that are qualitatively similar to those from the constant-speed parabolic Anderson model in earlier work by various authors. Our proofs consist of adaptations and refinements of their methods, as well as a variational convergence method borrowed from finite elements theory.
165

Controlling of dairy cattle breeding programs / Controlling von Milchrinderzuchtprogrammen

Schierenbeck, Sven 29 June 2010 (has links)
No description available.
166

Distribution asymptotique du nombre de diviseurs premiers distincts inférieurs ou égaux à m

Persechino, Roberto 05 1900 (has links)
Le sujet principal de ce mémoire est l'étude de la distribution asymptotique de la fonction f_m qui compte le nombre de diviseurs premiers distincts parmi les nombres premiers $p_1,...,p_m$. Au premier chapitre, nous présentons les sept résultats qui seront démontrés au chapitre 4. Parmi ceux-ci figurent l'analogue du théorème d'Erdos-Kac et un résultat sur les grandes déviations. Au second chapitre, nous définissons les espaces de probabilités qui serviront à calculer les probabilités asymptotiques des événements considérés, et éventuellement à calculer les densités qui leur correspondent. Le troisième chapitre est la partie centrale du mémoire. On y définit la promenade aléatoire qui, une fois normalisée, convergera vers le mouvement brownien. De là, découleront les résultats qui formeront la base des démonstrations de ceux chapitre 1. / The main topic of this masters thesis is the study of the asymptotic distribution of the fonction f_m which counts the number of distinct prime divisors among the first $m$ prime numbers, i.e. $p_1,...,p_m$. The first chapter provides the seven main results which will later on be proved in chapter 4. Among these we find the analogue of the Erdos-Kac central limit theorem and a result on large deviations. In the following chapter, we define several probability spaces on which we will calculate asymptotic probabilities of specific events. These will become necessary for calculating their corresponding densities. The third chapter is the main part of this masters thesis. In it, we introduce a random walk which, when suitably normalized, will converge to the Brownian motion. We will then obtain results which will form the basis of the proofs of those of chapiter 1.
167

[en] QUASIPERIODICITY AND THE POSITIVITY OF LYAPUNOV EXPONENTS / [pt] QUASE PERIODICIDADE E A POSITIVIDADE DOS EXPOENTES DE LYAPUNOV

LUCAS BARBOSA GAMA 11 January 2019 (has links)
[pt] O teorema de Benedicks e Carleson afirma que para a família quadrática existe um conjunto de parâmetros, com medida positiva, para os quais o expoente de Lyapunov é positivo no ponto crítico. Nesta dissertação apresentamos uma demonstração rigorosa e detalhada desse célebre resultado. Uma parte importante da demonstração é o estudo do comportamento quase periódico de um conjunto de órbitas. Além disso, um argumento de grandes desvios é utilizado para mostrar que os parâmetros que não satisfazem a propriedade desejada formam um conjunto pequeno. Tais técnicas apresentam um interesse intrínseco, já que têm se mostrado muito proveitosas para o estudo de outros problemas em sistemas dinâmicos. Combinando o teorema de Benedicks e Carleson ao teorema de Singer, conclui-se que para um conjunto de parâmetros com medida positiva, a função quadrática correspondente não admite atratores periódicos, indicando um comportamento caótico. Neste trabalho, também são estudados critérios para a positividade do expoente de Lyapunov de cociclos quase periódicos de Schrodinger, como o teorema de Herman. O estudo de cociclos de Schrodinger representa um importante tópico na área de física matemática. Mais ainda, algumas das generalizações de tais critérios utilizam as técnicas de Benedicks-Carleson. / [en] The Benedicks and Carleson theorem states that for the quadratic family there exists a set of parameters, with positive measure, for which the Lyapunov exponent is positive at the critical point. In this dissertation we present a rigorous and detailed proof of this famous result. An important part of the proof is the study of the quasi periodic behavior of a set of orbits. In addition, a large deviation argument is used to show that parameters which do not satisfy the desired property form a small set. Such techniques have an intrinsic interest, as they have proven fruitful in the study of other problems in dynamical systems. Combining Benedicks-Carlesons theorem with Singers theorem, we conclude that for a set of parameters with positive measure, the corresponding quadratic function does not admit periodic attractors, indicating its chaotic behavior. In this work we also study criteria for the positivity of the Lyapunov exponent of quasi-periodic Schrodinger cocycles, such as Hermans theorem. The study of the Schrodinger cocycles represents an important topic in mathematical physics. Moreover, some of the generalizations of such criteria use the techniques of Benedicks-Carleson.
168

Leergereedmaking van milieubenadeelde kleuters in 'n multikulturele leeromgewing / School readiness of milieu disadvantaged pre-schoolers in a multicultural learning environment

Bezuidenhout, Elizabeth 11 1900 (has links)
Summaries in Afrikaans and English / The aim of this study is to investigate the developmental deficits among milieu disadvantaged pre-schoolers in a multicultural learning environment and to identify the cause of these deficits. The availability of school readiness programmes and whether these programmes fulfil in the needs of milieu disadvantaged pre-schoolers are investigated. In the light of the theoretical and empirical research it appears that the profile of milieu disadvantaged pre-schoolers is in a process of change. Developmental shortcomings are experienced with regard to the following developmental aspects: Emotional Physical Cognitive Social, moral and aesthetical development According to the theoretical and empirical research these developmental deficits are caused by factors due to the home environment, the school as well as socio-demographic and socio-economic factors. From the research recommendations regarding the following were generated: The parents The pre-primary school The primary school The Department of Education Further researchSee file / Die doel met die onderhawige studie is om te bepaal watter ontwikkelingstekorte by milieubenadeelde kleuters in 'n multikulturele leeromgewing voorkom en om die faktore te identifiseer waardeur hierdie tekorte veroorsaak word. Daar word 'n breedvoerige blik gewerp op beskikbare leergereedheidsprogramme en in hoe 'n mate dit die ontwikkelingstekorte van milieubenadeelde kleuters aanspreek. Aan die hand van die literatuurstudie en 'n empiriese ondersoek blyk dit dat die beeld van milieubenadeelde kleuters besig is om te verander. Ontwikkelingstekorte word veral ten opsigte van die volgende aspekte ervaar: Emosionele Fisieke Kognitiewe Sosiale, morele en estetiese ontwikkeling Uit die literatuurstudie en die empiriese ondersoek blyk dit dat bogenoemde ontwikkelingstekorte veroorsaak word deur huislike, skolastiese, sosio-demografiese en sosio-ekonomiese faktore. Uit die ondersoek word aanbevelings ten opsigte van die volgende gegenereer: Die ouerhuis Die pre-primere skool Die primere skool Department of Education Verdere navorsing / Psychology of Education / M. Ed. (Sieklundige Opvoedkunde)
169

Le modèle GREM jumelé à un champ magnétique aléatoire

Persechino, Roberto 06 1900 (has links)
No description available.
170

The development of a root cause analysis process for variations in human performance

Rademeyer, Anerie 01 April 2009 (has links)
Problem-solving ability is now the most sought-after trait in up-and-coming executives, according to a survey of 1 000 executives conducted by Caliper Associates, reported in the Wall Street Journal by Hal Lancaster (Hoenig, 2002:338). This trait would include the ability to solve human performance problems, something many people tend to steer clear of. According to Piskurich (2002:57-58) and Rothwell, Hohne and King (2000:67-71), the most common problem-solving tools that are used when solving human performance problems are brainstorming, cause-and-effect analysis, and the five why’s technique. Although techniques such as these have proven to be robust and useful, what is required to solve human performance problems is a logical and verifiable process that can establish a data point about which relevant information can be recognized and gathered, and against which the conclusion can be evaluated, to have confirmed knowledge of the root cause of the problems. Unfortunately, existing root cause analysis processes tend to focus on processes and systems, rather than on individual performance (Bowling, 2003). The main objective of this study was to develop a root cause analysis process that would uncover the root cause(s) of uncontrolled variation(s) in human performance and prevent the recurrence of events causing the variation. In addition to addressing individual human performance incidents, it is also necessary continually to manage people’s performance to detect and address any occurrences (or recurrences) of performance variations. Therefore, in addition to the main objective, the study also aimed to develop a Human Performance Management Model that incorporated the root cause analysis process as a problem-solving tool. Action research was used in this study, because of the cyclical iterative nature of this type of research, and because it is a rigorous, responsive and flexible process. The study consisted of three cycles. The end result was a structured root cause analysis process – the Human Performance Variation Analysis (HPVA) process – that enables the systematic collection of valid and reliable information, as is required to solve variation in human performance. The HPVA process is a three-part process that consists of 11 steps. The process is in turn a tool that forms part of a ten-step Human Performance Management Model. The study contributes to the body of knowledge on human performance management by presenting the following: • a systematic root cause analysis process that uncovers the root causes of human performance problems effectively and consistently and that controls these causes of problems in a way that prevents the problems from recurring; and • a Human Performance Management Model that will help to sustain the new, improved performance; prevent the same or similar performance problem(s) in other areas of the organisation; and ultimately, create an environment and culture of continuous human performance improvement. / Thesis (PhD)--University of Pretoria, 2009. / Human Resource Management / unrestricted

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