Constructing spline models for isogeometric analysis is important in integrating design and analysis. Converting designed CAD (Computer Aided Design) models with B-reps to analysis-suitable volumetric T-spline is fundamental for the integration. In this thesis, we work on two directions to achieve this: (a) using Boolean operations and skeletons to build polycubes for feature-preserving high-genus volumetric T-spline construction; and (b) developing weighted T-splines with arbitrary degree for T-spline surface and volume modeling which can be used for analysis. In this thesis, we first develop novel algorithms to build feature-preserving polycubes for volumetric T-spline construction. Then a new type of T-spline named the weighted T-spline with arbitrary degree is defined. It is further used in converting CAD models to analysis-suitable volumetric T-splines. An algorithm is first developed to use Boolean operations in CSG (Constructive Solid Geometry) to generate polycubes robustly, then the polycubes are used to generate volumetric rational solid T-splines. By solving a harmonic field with proper boundary conditions, the input surface is automatically decomposed into regions that are classified into topologically either a cube or a torus. Two Boolean operations, union and difference, are performed with the primitives and polycubes are generated by parametric mapping. With polycubes, octree subdivision is carried out to obtain a volumetric T-mesh. The obtained T-spline surface is C2-continuous everywhere except the local region surrounding irregular nodes, where the surface continuity is elevated from C0 to G1. B´ezier elements are extracted from the constructed solid T-spline models, which are further used in isogeometric analysis. The Boolean operations preserve the topology of the models inherited from design and can generate volumetric T-spline models with better quality. Furthermore, another algorithm is developed which uses skeleton as a guidance to the polycube construction. From the skeleton of the input model, initial cubes in the interior are first constructed. By projecting corners of interior cubes onto the surface and generating a new layer of boundary cubes, the entire interior domain is split into different cubic regions. With the splitting result, octree subdivision is performed to obtain T-spline control mesh or T-mesh. Surface features are classified into three groups: open curves, closed curves and singularity features. For features without introducing new singularities like open or closed curves, we preserve them by aligning to the parametric lines during subdivision, performing volumetric parameterization from frame field, or modifying the skeleton. For features introducing new singularities, we design templates to handle them. With a valid T-mesh, we calculate rational trivariate T-splines and extract B´ezier elements for isogeometric analysis. Weighted T-spline basis functions are designed to satisfy partition of unity and linear independence. The weighted T-spline is proved to be analysis-suitable. Compared to standard T-splines, weighted T-splines have less geometrical constraint and can decrease the number of control points significantly. Trimmed NURBS surfaces of CAD models are reparameterized with weighted T-splines by a new edge interval extension algorithm, with bounded surface error introduced. With knot interval duplication, weighted T-splines are used to deal with extraordinary nodes. With B´ezier coefficient optimization, the surface continuity is elevated from C0 to G1 for the one-ring neighborhood elements. Parametric mapping and sweeping methods are developed to construct volumetric weighted T-splines for isogeometric analysis. Finally, we develop an algorithm to construct arbitrary degree T-splines. The difference between odd degree and even degree T-splines are studied in detail. The methods to extract knot intervals, calculate new weights to handle extraordinary nodes, and extract B´ezier elements for analysis are investigated with arbitrary degrees. Hybrid degree weighted Tspline is generated at designated region with basis functions of different degrees, for the purpose of performing local p-refinement. We also study the convergence rate for T-spline models of different degrees, showing that hybrid degree weighted T-splines have better performance after p-refinement. In summary, we develop novel methods to construct volumetric T-splines based on polycube and sweeping methods. Arbitrary degree weighted T-spline is proposed, with proved analysis-suitable properties. Weighted T-spline basis functions are used to reparameterize trimmed NURBS surfaces, handling extraordinary nodes, based on which surface and volumetric weighted T-spline models are constructed for isogeometric analysis.

A general framework is described for the solution of two-phase fluid-object interaction problems on the basis of coupling a distributed-Lagrange-multiplier fictitious domain method and a level-set method, intended for application to the problem of seabed scour by ice ridges. The resulting equations are discretized in space using stabilized finite-element methods and integrated in time using the generalized-α method. This approach is simple to implement and applicable to both structured and unstructured meshes in two and three dimensions. By means of examples, it is shown that despite the simplicity of the approach, good results are obtained in comparison with other more computationally demanding methods. A robust approach is utilized for constructing signed-distance functions on arbitrary meshes by introducing artificial numerical diffusivity to improve the robustness of classical signed-distance construction approaches without resorting to common pseudo-time relaxation. Under this approach, signed-distance functions can be rapidly constructed while preserving the numerical convergence properties and, generally, having minimal interfacial perturbation. The method is then applied with a modified deformation procedure for fast and efficient mesh adaptivity, including a discussion how it may be used in computational fluid dynamics. The two-phase fluid-object interaction approach is then customized for modeling of the seabed scour and soil-pipe interaction. In this approach, complex history-dependent soil constitutive models are replaced with a simple strain-rate dependent model. Utilization of this constitutive model along with the framework developed earlier leads to the treatment of seabed scour as a two-phase fluid-object interaction, and the soil-pipe interaction as a fluid-structure interaction problem without the need for remeshing. Good agreement with past experimental and numerical studies are obtained using our approach. The dissertation is concluded by conducting a parametric study of seabed scour in two- and three-dimensions. / text

The Principle of Arbitrary Order with the Accent on Contentious Trial Proceedings The purpose of my thesis is to analyse the principle of arbitrary order and its role in recent civil-procedure legislation both in the Czech Republic and abroad. The reason for my research is the incessant discussion of experts and the continuing need for amendment of the Civil Procedure Code to ensure a balance between examination of facts and reasonable time of hearing. The thesis is composed of six chapters. Chapter One is introductory and defines basic terminology used in the thesis, especially the fundamental principles of civil procedure and principles of procedural order. Chapter Two describes historical development of arbitrary order in our country from the Austro-Hungarian Empire. Chapter Three is subdivided into three parts. Part One highlights the most important international-law and constitutional grounds for the current order of the proceedings. Part Two and Three looks at amendments which brought substantial changes to the principle of arbitrary order after 2000. Chapter Four is focused on today's legislation and problems resulting from its ambiguous interpretation. Chapter Five provides a view of foreign legislation and its approach to the selected topic. The chosen jurisdictions are Austria, Germany and...

[pt] No presente trabalho o método de Rayleigh-Ritz é utilizado na determinação dos campos modais e dos números de onda de corte em guias de onda de seção arbitrária. Inicialmente, o método é aplicado com funções de base polinomiais, sendo a seção transversal do guia aproximada por um polígono convexo. Este tipo de função limitou o número de modos que podem ser calculados, uma vez que polinômios de grau alto geram instabilidades computacionais e overflow. Utilizando a mesma metodologia, os campos modais em guias de onda superquadráticos são analisados. Entretanto, as funções de base polinomiais são substituídas por funções trigonométricas, produzindo um modelo numérico capaz de computar um grande número de modos em um tempo de execução razoável. Os guias superquadráticos constituem uma classe de guias uniformes, incluindo guias circulares, elípticos, quase retangulares e outros de seções intermediárias. Conseqüentemente, eles são úteis na construção de diversos dispositivos em guias de onda, incluindo transições de diferentes seções, tais como circular para elíptica e circular para retangular. O método do casamento de modos é aplicado na determinação da matriz de espalhamento de descontinuidades entre guias superquadráticos. Diversas aplicações numéricas são apresentadas e comparadas com resultados obtidos através de outras técnicas. / [en] In the present work, the modal fields and cutoff wavenumbers of arbitrary cross section waveguides are determined using the Rayleigh-Ritz method. Initially, the method is applied to waveguides with cross section approximated by a convex polygon. Polynomial basis functions are used. Such basis functions limit the number of modes that can be computed, since polynomials of high degree generate computer instabilities and overflow. Using the same methodology, the modal fields of superquadric waveguides are analyzed. Polynomial basis functions are replaced by trigonometric functions, however, producing an efficient numerical model capable of computing a large number of modes with a reasonable computer time. Superquadric waveguides constitute a class of uniform waveguides that include circular, elliptical, almost rectangular waveguides and a series of intermediate cross section waveguides. As a consequence they are quite useful in the construction of several devices, including transitions between waveguides of different cross sections, such as circular to elliptical and circular to rectangular. The mode matching technique is applied to the determination of the scattering matrix of discontinuities between superquadric waveguides. Several numerical applications are presented and compared to results obtained from other techniques.

La Décomposition Modale Empirique (Empirical Mode Decomposition - EMD) ou la Transformation de Hilbert-Huang (HHT) est une nouvelle méthode d'analyse temps-fréquence qui est particulièrement adaptée pour des séries temporelles nonlinéaires et non stationnaires. Cette méthode a été proposée par NE. HUANG. il y a plus de dix ans. Pendant les dix dernières années, plus de 1000 articles ont appliqué cette méthode dans le cadre de diverses applications ou domaines de recherche. Dans cette thèse, nous appliquons cette méthode à des séries temporelles de turbulence, pour la première fois, et à des séries temporelles environnementales. Nous avons obtenu comme résultat le fait que la méthode EMD correspond à un banc de filtre dyadique (ou quasi-dyadique) pour la turbulence pleinement développée. Pour caractériser les propriétés intermittentes d'une série temporelle invariante d'échelle, nous avons généralisé l'analyse spectrale de Hilbert-Huang classique à des moments d'ordre arbitraire $q$, pour effectuer ce que nous avons appelé ``analyse spectrale de Hilbert d'ordre arbitraire''. Ceci fournit un nouveau cadre pour analyser l'invariance d'échelle directement dans un espace amplitude-fréquence, en estimant une intégrale marginale d'une pdf jointe $p(\omega,\mathcal{A})$ de la fréquence instantanée $\omega$ et de l'amplitude $\mathcal{A}$. Nous validons tout d'abord la méthode en analysant des séries temporelles de mouvement Brownien fractionnaire, et en analysant des séries temporelles multifractales synthétiques, en tant que modèle respectivement de processus monofractals et multifractals. Nous comparons les résultats obtenus avec la nouvelle méthode, à l'analyse classique utilisant les fonctions de structure: nous trouvons numériquement que la méthodologie utilisant l'approche de Hilbert fournit un estimateur plus précis pour le paramètre d'intermittence. Avec une hypothèse de stationarité, nous proposons un modèle analytique pour la fonction d'autocorrélation des incréments de séries temporelles de vitesse $\Delta u_{\ell}(t)$, où $\Delta u_{\ell}(t)=u(t+\ell)-u(t)$, et $\ell$ est l'incrément temporel. Dans le cadre de ce modèle, nous prouvons analytiquement que, si une loi de puissance est valide pour la série d'origine, la position minimisant la fonction d'autocorrélation de la variable d'origine est égale exactement au temps de séparation $\ell$ lorsque $\ell$ appartient à la zone invariante d'échelle. Ce modèle prédit une loi de puissance pour la valeur minimum, comportement vérifié par une simulation de mouvement Brownien fractionnaire et à partir de données expérimentales de turbulence. En introduisant une fonction cumulative pour la fonction d'autocorrélation, la contribution en échelle est alors caractérisée dans l'espace de fréquence de Fourier. Nous observons que la contribution principale à la fonction d'autocorrélation provient des grandes échelles. La même idée est appliquée à la fonction de structure d'ordre 2. Nous obtenons que celle-ci est également fortement influencée par les grandes échelles, ce qui montre que ceci n'est pas une bonne approche pour extraire les exposants invariants d'échelle d'une série temporelle lorsque les données sont caractérisées par des grandes échelles énergétiques. Nous appliquons ensuite cette méthodologie Hilbert-Huang à une base de données de turbulence homogène et presque isotrope, pour caractériser les propriétés multifractales invariantes d'échelle des série temporelles de vitesse en turbulence pleinement développée. Nous obtenons un comportement invariant d'échelle pour la pdf jointe $p(\omega,\mathcal{A})$ avec un exposant proche de la valeur de Kolmogorov. Nous estimons les exposants $\zeta(q)$ dans un espace amplitude-fréquence, pour la première fois. L'hypothèse d'isotropie est testée échelle par échelle dans l'espace amplitude-fréquence. Nous obtenons que le rapport d'isotropie généralisé décroit linéairement avec le moment $q$. Nous effectuons également l'analyse d'une série temporelle de température (scalaire passif) possédant un effet de rampe marqué (ramp-cliff). Pour ces données, l'approche traditionnelle utilisant les fonctions de structure ne fonctionne pas. Mais la nouvelle méthode développée dans cette thèse fournit un net régime invariant d'échelle jusqu'au moment $q=8$. Les exposants $\xi_{\theta}(q)-1$ sont très proches des exposants $\zeta(q)$ obtenus par l'approche des fonctions de structure pour la vitesse longitudinale. Nous nous intéressons ensuite à l'auto-similarité étendue (Extended Self Similarity - ESS) dans le cadre Hilbert-Huang. En ce qui concerne la méthode ESS, qui est devenue classique en turbulence, nous adaptons l'approche pour le cas Hilbert-Huang dans un espace de fréquence, et nous constatons que le modèle lognormal, avec un coefficient adéquat, fournit une très bonne estimation des exposants invariants d'échelle. Finalement nous appliquons la nouvelle méthodologie à des données environnementales: des débits de rivières, et des données de turbulence marine dans la zone de surf. Dans ce dernier cas, la méthode ESS permet de séparer les ondes de vent de la turbulence à petite échelle.

Value-added models are complex statistical formulas that aim to isolate the effect a teacher has on student learning. States and districts across the nation are adopting laws and policies that will evaluate teachers, in part, using the results provided by value-added models. In many states and districts, these evaluations will be used to inform high-stakes decisions about teacher salary and retention. However, value-added models are imperfect tools for assessing teacher effectiveness, and many scholars have argued that they are not appropriate for use in high-stakes decisions. This Article provides a brief history of the use of value-added models in public education and summarizes the major criticisms of using value-added models. In this context, the Article analyzes and evaluates the extent to which substantive due process claims brought by teachers adversely affected by the results of value-added models will be successful. The Article concludes that while the system as a whole is rationally related to the objective of improving the overall effectiveness of the teaching workforce, in certain cases, individual teachers will be able to successfully claim that the results of their value-added model led to a termination that was arbitrary and capricious. Finally, the paper offers some recommendations to states and school districts on how to implement an evaluation system using value-added models to avoid substantive due process violations. / text

The gyromagnetic ratio of bound particles is an active field of experimental and theoretical research. Early measurements of corrections to the bound g-factor came from experiments involving hydrogen-like ions. As the sensitivity of such experiments has increased, it has become possible to instead use them to measure the electron-ion mass ratio -- but only if the theoretical bound g-factor is known with sufficient precision for these systems. By constructing an effective nonrelativistic Lagrangian, we derive leading order binding and recoil corrections for systems comprised of particles with arbitrary spin. Lagrangians for spin one-half and spin one-theories are developed, before moving on to the more general case of arbitrary spin. In each case, an effective nonrelativistic Lagrangian taking into account all relevant terms is constructed. The coefficients of this Lagrangian are then fixed by calculating scattering processes in both the relativistic and nonrelativistic theories. A relativistic framework for dealing with particles of arbitrary spin is considered. In this framework the relevant terms in the scattering process are heavily constrained by the symmetries required of the electromagnetic current. This allows the determination of an effective Lagrangian valid for arbitrary spin. It is found that the only coefficients which depend upon the spin of the particle in question involve derivatives of the magnetic field. This general form is consistent with the previously derived Lagrangians for spin one-half and spin one particles. With this effective nonrelativistic Lagrangian, the leading order binding and recoil corrections to the bound gyromagnetic ratio are calculated. These corrections are found to be universal, independent of the spin of the particles involved. This is understood as a consequence of the Bargmann-Michel-Telegdi equation.

No description available.

No abstract available. / Dissertation (LLM)--University of Pretoria, 2012. / gm2014 / Centre for Human Rights / unrestricted

Pseudomonas aeruginosa is an opportunistic pathogen that express a plethora of virulence components controlled through two-component regulatory systems that allow for sensing and responding to environmental stimuli. This study was aimed at identifying transcription regulators of algZ that encodes the histidine sensor kinase (AlgZ) of the AlgZR two-component regulatory system. To understand how the algZ gene is transcriptionally controlled, transposon mutagenesis was used to create a mutant library with varying algZ expression based on their b-Galactosidase activity. The gene PA3327 was identified as a potential regulator of algZ expression using arbitrary PCR. This gene encodes a probable non-ribosomal peptide synthetase responsible for the biosynthesis of secondary metabolites such as antibiotics. Further experiments are required to understand how PA3327 transcriptionally regulates algZ expression and its physiological role in the organism. Because the AlgZ/R system regulates virulence, it is possible to attenuate virulence by targeting the expression of algZ gene.