There has been great scholarly interest in examining the management, proliferation, and dynamic articulations of borders through an actor-network lens in recent years. In tracing the networks of Mohamed Harkat, the irregular arrival of a particular group of Tamil migrants, and Deepan Budlakoti, I demonstrate how the border is a fluid entity composed of socio-technical actors dispersed across time and space capable of producing varying degrees of membership statuses. In exploring the cases of these non-citizens, this thesis aims to understand what each of these multi-level networks tells us about the notion of borders and bordering practices alike. This study contributes to the expanding literature that situates the border as a fluid and malleable entity that is made up of interwoven socio-technical practices, discourses, symbols, institutions, and networks through which power is dispersed and the binary distinctions between membership and non-membership increasingly become layered concepts.

The annotated papers that are submitted as part of this thesis consider the phenomenon of colour at the fundamental, technical, and application levels, and they were written and published by Oulton between 1990 and 2009. The papers disclose significant insights by the author into colorimetric modeling theory and report aspects of the author's work that have led to commercially successful practical applications. The academic significance of these papers is evident in their citation record; their practical value is shown by a number of successful industrial collaboration programmes, and through the award of national prizes for innovation by the Worshipful Company of Dyers, and the Society of Dyers and Colorists. The published research primarily concerns digital devices that either capture or reproduce coloured images. For example, the research problem of how to calibrate the colour on computer CRT screens, which was thought at the time to be intractable, was reported by Oulton in paper 1 to be solved at the two to three significant figure level of colorimetric accuracy. This world leading level of accuracy was subsequently confirmed using a comprehensive data set in paper 7, and has been exploited internationally in commercial computer aided design and colour communication systems by Textile Computer Systems Ltd and Datacolor Inc. Further research problems resolved by Oulton in the presented papers include how to predict the colorimetric sensitivity of dye recipes; how to design, test, and fine-tune the spectral response of digital cameras; and how the individual customers in a shop can be tracked automatically to reveal their buying behavior, using coloured CCTV images.The challenge to the standard CIE colorimetric model posed by the results of Dr W.A. Thornton was analyzed and satisfactorily explained by Oulton in papers 2, 3 and 4. It is also shown that Thornton's results do not in any way compromise either the practice of colorimetry based on the CIE Standard Observer, or the validity of its quantifying data sets. It is also additionally shown under the annotation of paper 4 presented here, that the success of the CIE colorimetric model has a clearly demonstrable theoretical basis.In all but one of the presented papers the convention is maintained that the standard CIE XYZ co-ordinate model should be used as the reference basis, when modeling the properties of colour and quantifying its uses. The final paper to be published (and presented here as paper 4) challenges this convention and demonstrates that a context free and formally defined alternative reference basis may be used in colorimetric modeling with significant advantage. It is also shown in paper 4 that under the specified axioms, any cross dependency that is potentially non linear can in principle be resolved into its component scalar and additive relationships, and that the causes of scalar non linearity may be characterized independently from the causes of linearly additive cross dependency. The result is a widely applicable analytical and experimental design method for resolving complex cross dependent relationships in general and in particular, for resolving those between the spectral visual stimuli and the psychophysical response to them.

This thesis aims to understand the role of public governance (national laws and regulations) in addressing poor working conditions on South African fruit farms connected to global production networks (GPN), at the intersection of global private (codes of conduct) and local civil society organisation (CSO) initiatives. A particular objective of the investigation is to understand the extent to which public governance is able to address working conditions on South African fruit export farms, taking into account wider global commercial pressures inherent in fruit GPNs. Much analysis of global private and governance by local CSOs has not sufficiently addressed the role of public governance. Research focusing on public governance in addressing working conditions in South African fruit has not sufficiently accounted for the multi-scalar interactions between lead firm supermarkets, national suppliers and local fruit producers. These interactions are positioned to shape and influence regulatory outcomes for different groups of permanent and casual farmworkers. The thesis seeks to address the following central research question: ‘To what extent do multi-scalar tensions in global production networks (GPNs) challenge the public governance of working conditions, and what are the lessons from labour operating in South African fruit production?’This research draws upon the GPN analytical framework and public governance research, in order to conceptualise the multi-scalar commercial and governance processes that play out in the South African fruit export sector. In doing so, this research seeks to contribute to existing GPN and public governance literatures. Previous GPN research has not sufficiently investigated the role of public governance (laws and regulations) in addressing working conditions, partly due to an assumption that neoliberal policies have eroded the ability of developing states to regulate labour incorporated into global production. This problematic is beginning to be addressed, due to increasing academic acknowledgement of the central regulatory role nation states continue to play in addressing working conditions in global production, at the intersection of global private (codes of conduct) initiatives and governance by local CSOs (NGO and trade union activity). Additionally, this thesis seeks to bring together two separate strands of ‘governance’ research in global production networks, which have thus far been investigated separately; the governance of commercial interactions on the one hand, and the governance of labour on the other. A key theoretical argument is that understanding challenges facing the public governance of labour requires a broader conceptualisation of the governance of multi-scalar commercial interactions in global production, which shape and influence workforce composition at local farm level. This thesis argues that an inherent multi-scalar tension exists on the one hand between ‘global commercial pressures’ exerted by global lead firms over national suppliers and local producers driving workforce casualisation, and on the other hand a ‘global governance deficit’ at the core of which lies a public governance deficit facing increasing numbers of casual workers, characterised by minimum wages insufficient to meet living costs and a lack of trade union representation. This tension, it is argued, underpinned the crisis in South African fruit in 2012/13, when casual workers mobilised to demand an increase in the agricultural minimum wage, and threatened the fruit value chain by blocking the main arterial routes to Cape Town port. The policy implications of this thesis are that nation states are required to adopt multi-scalar interventions which transcend traditional forms of governance, in order to address the global commercial pressures inherent in GPNs and protect increasing numbers of casual workers in this context.

The advent of laser cooling and optical manipulation for atomic samples revolutionized atomic physics in 1990’s, allowing the creation of new phases of matter, more accurate atomic clocks, and enabling leading candidates for the first functional quantum computer. This could not have been predicted at the time, and is a testament to the value of fundamental research for its own sake. These same laser cooling techniques are now being applied to simple molecular systems with the same revolutionary potential. In this thesis, I will present a range of experiments exploring these schemes in a new class of molecules, the diatomic alkaline earth hydrides. We present the creation and characterization of a bright beam of cold barium hydride molecules, high precision spectroscopy of these samples, as well as optical deflection and transverse cooling. This represents the first laser cooling of a Hydride molecule. This is a crucial step towards the creation of new cold molecular samples for a variety of scientific applications. In the final chapter, I will change gears, and introduce new ideas for the detection of scalar field dark matter. While this variety of dark matter is typically searched for using atomic clocks, I will show that the same coupling also leads to anomalous acceleration of test masses. This acceleration would be detectable using both a network of precision acceleration sensors known as the IGETS network, and by the LIGO observatory. This new technique will compliment existing search strategies, and has higher sensitivity for a wide region of parameter space.

The goal of this project was to study pipelined processor architectures along with instruction and data cache. Chosen pipelined architecture should be designed and implemented using VHDL language. Firstly, I decided to implement the subscalar architecture first, secondly, three versions of scalar architecture. For these architectures synthesis into FPGA was done and performance of these architectures was compared on chosen algorithm. In the next part of this thesis I designed and implemented instruction and data cache logic for both architectures. However I was not able to synthetise these caches. Last chapter of this thesis deals with the superscalar architecture, which is the architecture of nowadays.

Vingt années se sont écoulées depuis la découverte de l'expansion accélérée de l'Univers, ravivant l'intérêt pour les théories alternatives de la gravité. Ajouter un champ scalaire à la métrique habituelle de la relativité générale est l'une des manières les plus simples de modifier notre théorie de la gravité. En parallèle, nos connaissances sur les trous noirs et les étoiles à neutrons sont en plein essor, grâce notamment au développement de l'astronomie par ondes gravitationnelles. Cette thèse se situe au carrefour entre les deux domaines : elle étudie les propriétés des objets compacts dans les théories tenseur-scalaire généralisées. Je commence par rappeler les théorèmes d'unicité essentiels établis depuis les années soixante-dix. Après avoir présenté le théorème d'unicité pour les trous noirs en théorie de Horndeski, je l'étends aux étoiles. La deuxième partie de cette thèse détaille les différentes manières de contourner ce théorème. Parmi elles, je présente des solutions où la dépendance temporelle du champ scalaire permet de le raccorder à une solution cosmologique, mais aussi des trous noirs statiques et asymptotiquement plats. Dans la troisième partie, j'établis un critère important pour la stabilité de ces solutions, qui s'appuie sur leur structure causale. C'est aussi l'occasion d'étudier la propagation des ondes gravitationnelles au voisinage de trous noirs, et de sélectionner les théories dans lesquelles les ondes gravitationnelles se propagent à la même vitesse que la lumière. / Twenty years have passed since the discovery of the accelerated expansion of the Universe, reviving the interest for alternative theories of gravity. Adding a scalar degree of freedom to the usual metric of general relativity is one of the simplest ways to modify our gravitational theory. In parallel, our knowledge about black holes and neutron stars is booming, notably thanks to the advent of gravitational wave astronomy. This thesis is at the crossroads between the two fields, investigating the properties of compact objects in extended scalar-tensor theories. I start by reviewing essential no-hair results established since the seventies. After discussing the no-hair theorem proposed for black holes in Horndeski theory, I present its extension to stars. The second part of the thesis investigates in detail the various ways to circumvent this theorem. These notably include solutions with a time-dependent scalar field in order to match cosmological evolution, but also static and asymptotically flat configurations. In a third part, I establish an important stability criterion for these solutions, based on their causal structure. It is also the occasion to study the propagation of gravitational waves in black hole environments, and to select the theories where gravitational waves travel at the same speed as light.

In this work, we study two problems in quantum field theory from a boundary point of view. Our perspective is motivated by the bootstrap philosophy, which aims to understand how principles such as kinematics, unitarity, and symmetry constrain physical observables. Regarding kinematics, we actually first relax the unitarity constraint and investigate thenon-unitary representations of the boundary superconformal algebra for AdS4 with N = 2 supercharges. In particular, we identify multiplets containing partially massless (PM) fields, as well as other exotic shortening conditions and structures exclusive to the nonunitary regime. Then, turning on interactions, we study a problem centered in dynamics: we investigate the structure of the flat space wavefunctional in scalar field theories with nonlinearly realized symmetries. In particular, we highlight the so-called exceptional scalar field theories, which are the nonlinear sigma model, Dirac-Born-Infeld, and (special) galileon theories. We find that nonlinearly realized symmetries imply soft theorems which must be obeyed by the wavefunction. Moreover, we develop bootstrap techniques utilizing this information along with the singularity structure of the wavefunction to fix its form. In addition, we systematize this construction into a novel set of recursion relations.

Even though there is a multitude of observational evidence from cosmology and astrophysics, the standard model does not include a suitable dark matter candidate and therefore physics beyond the standard model is necessary. There are hypotheses of what the particle candidate could be coming from theories such as supersymmetry or extra dimensions. The processes producing these particles are understood very well from the theoretical perspective. The problem is that these processes have not been observed in any detectors. Therefore the nature of the dark matter remains unknown. However, it is clear that the dark matter-particle interacts with ordinary matter through gravity and in general, candidates may also interact through the weak force. These candidates are called Weakly Interacting Massive Particles. Therefore, by studying weak processes (weak in the sense that the processes are interactions mediated by a force weaker than the Electro-Magnetic and Quantum-Chromo dynamical-forces, not necessarily the weak force of the standard model) in the large hadron collider it may be possible to pose constraints on the dark matter signatures. One possible process which specifically involves the standard model electroweak interaction, which will be the model for the project, is the emission of scalar dark matter particles from the Z boson,which would result in a final state characterized by a Z boson and missing transverse energy. Simulations of the model and calculations of the cross section are done for different masses, ranging from 20−680 GeV, of the scalar dark matter particle and then compared to a standard model background process. Investigations are made whether or not it would be possible to detect darkmatter signals in the background. With the assumptions made, the results indicate that a signal from dark matter with a mass of around 40−150 GeV could not be rejected up to 5σ.

Scalar fields are used in many disciplines to represent scalar quantities over some spatial domain. Their versatility and the potential to model a variety of real-world phenomena has made scalar fields a key part of modern data analysis. Examples range from modeling scan results in medical applications (e.g. Magnetic Resonance Imaging or Computer Tomography), measurements and simulations in climate and weather research, or failure criteria in material sciences. But one thing that all applications have in common is that the data is always affected by errors. In measurements, potential error sources include sensor inaccuracies, an unevenly sampled domain, or unknown external influences. In simulations, common sources of error are differences between the model and the simulated phenomenon or numerical inaccuracies. To incorporate these errors into the analysis process, the data model can be extended to include uncertainty. For uncertain scalar fields that means replacing the single value that is given at every location with a value distribution. While in some applications, the influence of uncertainty might be small, there are a lot of cases where variations in the data can have a large impact on the results. A typical example is weather forecasts, where uncertainty is a crucial part of the data analysis. With increasing access to large sensor networks and extensive simulations, the complexity of scalar fields often grows to a point that makes analysis of the raw data unfeasible. In such cases, topological analysis has proven to be a useful tool for reducing scalar fields to their fundamental properties. Scalar field topology studies structures that do not change under transformations like scaling and bending but only depend on the connectivity and relative value differences between the points of the domain. While a lot of research has been done in this area for deterministic scalar fields, the incorporation of uncertainty into topological methods has only gained little attention so far. In this thesis, several methods are introduced that deal with the topological analysis of uncertain scalar fields. The main focus lies on providing fundamental research on the topic and to drive forward a rigorous analysis of the influence of uncertainty on topological properties. One important property that has a strong influence on topological features are stochastic dependencies between different locations in the uncertain scalar field. In the first part of this thesis, we provide a method for extracting regions that show linear dependency, i.e. correlation. Using a combination of point-cloud density estimation, clustering, and scalar field topology, our method extracts a hierarchical clustering. Together with an interactive visualization, the user can explore the correlation information and select and filter the results. A major benefit of our approach is the comprehensive handling of correlation. This also includes global correlation between distant points and inverse correlation, which is often only partially handled by existing methods. The second part of this thesis focuses on the extraction of topological features, such as critical points or hills and valleys of the scalar field. We provide a method for extracting critical points in uncertain scalar fields and track them over multiple realizations. Using a novel approach that operates in the space of all possible realizations, our method can find all critical points deterministically. This not only increases the reliability of the results but also provides complete knowledge that can be used to study the relation and behavior of critical points across different realizations. Through a combination of multiple views, we provide a visualization that can be used to analyze critical points of an uncertain scalar field for real-world data. In the last part, we further extend our analysis to more complex feature types. Based on the well-known contour tree that provides an abstract view on the topology of a deterministic scalar field, we use an approach that is similar to our critical point analysis to extract and track entire regions of the uncertain scalar field. This requires solving a series of new challenges that are associated with tracking features in the multi-dimensional space of all realizations. As our research on the topic falls under the category of fundamental research, there are still some limitations that have to be overcome in the future. However, we provide a full pipeline for extracting topological features that ranges from the data model to the final interactive visualization. We further show the applicability of our methods to synthetic and real-world data. / Skalarfelder sind Funktionen, die jedem Punkt eines Raumes einen skalaren Wert zuweisen. Sie werden in vielen verschiedenen Bereichen zur Analyse von skalaren Messgrößen mit räumlicher Information eingesetzt. Ihre Flexibilität und die Möglichkeit, viele unterschiedliche Phänomene der realen Welt abzubilden, macht Skalarfelder zu einem wichtigen Werkzeug der modernen Datenanalyse. Beispiele reichen von medizinischen Anwendungen (z.B. Magnetresonanztomographie oder Computertomographie) über Messungen und Simulationen in Klima- und Wetterforschung bis hin zu Versagenskriterien in der Materialforschung. Eine Gemeinsamkeit all dieser Anwendungen ist jedoch, dass die erfassten Daten immer von Fehlern beeinflusst werden. Häufige Fehlerquellen in Messungen sind Sensorungenauigkeiten, ein ungleichmäßig abgetasteter Betrachtungsbereich oder unbekannte externe Einflussfaktoren. Aber auch Simulationen sind von Fehlern, wie Modellierungsfehlern oder numerischen Ungenauigkeiten betroffen. Um die Fehlerbetrachtung in die Datenanalyse einfließen lassen zu können, ist eine Erweiterung des zugrunde liegenden Datenmodells auf sogenannte \emph{unsicheren Daten} notwendig. Im Falle unsicherer Skalarfelder wird hierbei statt eines festen skalaren Wertes für jeden Punkt des Definitionsbereiches eine Werteverteilung angegeben, die die Variation der Skalarwerte modelliert. Während in einigen Anwendungen der Einfluss von Unsicherheit vernachlässigbar klein sein kann, gibt es viele Bereiche, in denen Schwankungen in den Daten große Auswirkungen auf die Resultate haben. Ein typisches Beispiel sind hierbei Wettervorhersagen, bei denen die Vertrauenswürdigkeit und mögliche alternative Ausgänge ein wichtiger Bestandteil der Analyse sind. Die ständig steigende Größe verfügbarer Sensornetzwerke und immer komplexere Simulationen machen es zunehmend schwierig, Daten in ihrer rohen Form zu verarbeiten oder zu speichern. Daher ist es wichtig, die verfügbare Datenmenge durch Vorverarbeitung auf für die jeweilige Anwendung relevante Merkmale zu reduzieren. Topologische Analyse hat sich hierbei als nützliches Mittel zur Verarbeitung von Skalarfeldern etabliert. Die Topologie eines Skalarfeldes umfasst all jene Merkmale, die sich unter bestimmten Transformationen, wie Skalierung und Verzerrung des Definitionsbereiches, nicht verändern. Hierzu zählen beispielsweise die Konnektivität des Definitionsbereiches oder auch die Anzahl und Beziehung von Minima und Maxima. Während die Topologie deterministischer Skalarfelder ein gut erforschtes Gebiet ist, gibt es im Bereich der Verarbeitung von Unsicherheit im topologischen Kontext noch viel Forschungspotenzial. In dieser Dissertation werden einige neue Methoden zur topologischen Analyse von unsicheren Skalarfeldern vorgestellt. Der wesentliche Teil dieser Arbeit ist hierbei im Bereich der Grundlagenforschung angesiedelt, da er sich mit der theoretischen und möglichst verlustfreien Verarbeitung von topologischen Strukturen befasst. Eine wichtige Eigenschaft, die einen starken Einfluss auf die Struktur eines unsicheren Skalarfeldes hat, ist die stochastische Abhängigkeit zwischen verschiedenen Punkten. Im ersten Teil dieser Dissertation wird daher ein Verfahren vorgestellt, das das unsichere Skalarfeld auf Regionen mit starker linearer Abhängigkeit, auch \emph{Korrelation} genannt, untersucht. Durch eine Kombination aus hochdimensionaler Punktwolkenanalyse, Clusterbildung und Skalarfeldtopologie extrahiert unsere Methode eine Hierarchie von Clustern, die die Korrelation des unsicheren Skalarfeldes repräsentiert. Zusammen mit einer interaktiven, visuellen Aufbereitung der Daten wird dem Nutzer so ein explorativer Ansatz zur Betrachtung der stochastischen Abhängigkeiten geboten. Anzumerken ist hierbei, dass unser Verfahren auch globale und inverse Korrelation abdeckt, welche in vielen verwandten Arbeiten oft nicht vollständig behandelt werden. Der zweite Teil dieser Dissertation widmet sich der Analyse und Extraktion von topologischen Merkmalen, wie kritischen Punkten oder ganzen Hügeln oder Tälern im Funktionsgraphen des Skalarfeldes. Hierzu wird ein Verfahren zur Berechnung von kritischen Punkten vorgestellt, das diese auch über viele verschiedene Realisierungen des unsicheren Skalarfeldes identifizieren und verfolgen kann. Dies wird durch einen neuen Ansatz ermöglicht, der den Raum aller möglichen Realisierungen nach geometrischen Strukturen untersucht und somit kritische Punkte deterministisch berechnen kann. Dadurch, dass mit diesem Verfahren keine kritischen Punkte ausgelassen werden, steigt nicht nur die Vertrauenswürdigkeit der Resultate, sondern es wird außerdem möglich, Beziehungen zwischen kritischen Punkten zu untersuchen. Zu diesen Beziehungen gehört beispielsweise das Wandern von kritischen Punkten über verschiedene Positionen oder auch die Entstehung von Skalarwerthügeln oder -tälern. Um die Resultate visuell zu untersuchen, stellen wir mehrere verknüpfte Ansichten bereit, die eine Analyse von kritischen Punkten auch in realen Daten ermöglichen. Im letzten Teil dieser Arbeit erweitern wir die Betrachtung der Topologie von kri\-ti\-schen Punkten auf komplexere Strukturen. Basierend auf dem \emph{Konturbaum}, der eine abstrakte Repräsentation der Topologie eines deterministischen Skalarfeldes ermöglicht, untersuchen wir, wie ganze Regionen des Skalarfeldes von Unsicherheit betroffen sind. Dies führt zu einer Reihe von neuen theoretischen und auch praktischen Herausforderungen, wie der stark steigenden Komplexität der notwendigen Berechnungen oder Inkonsistenzen bei der Verfolgung von topologischen Strukturen über mehrere Realisierungen. Auch wenn zur Anwendung unserer Verfahren auf reale Daten aufgrund des großen Möglichkeitsraumes von unsicheren Skalarfeldern noch Einschränkungen notwendig sind, sind viele der theoretischen Erkenntnisse allgemeingültig. Zur Betrachtung der Ergebnisse werden verschiedene Visualisierungen genutzt, um die extrahierten topologischen Strukturen anhand von synthetischen und realen Daten zu zeigen.

Une configuration en T-jonction a été étudiée pour sa simplicité en géométrie en comparant avec d’autres mélangeurs en industrie. Plus particulièrement, j’ai effectué des simulations numériques directes avec OpenFOAM des T-jonction convergent à section circulaire et rectangulaire. Les fluides Newtonien et non-Newtonien (modèle Bird-Carreau) ont été pris en compte. Dans un premier temps, j’ai comparé mes données avec le travail expérimental de Nguyen [1] sur le T-jonction circulaire en régime deflecting. J’arrive à valider la DNS avec les données expérimentales. L’organisation des structures cohérentes sont illustrées en régime laminaire et turbulent en Newtonien et en non-Newtonien. Dans un deuxième temps, j’ai simulé deux régimes (deflecting et impinging) dans un T-jonction rectangulaire en Newtonien et en non-Newtonien. J’ai montré l’existence de structures cohérentes (par example kidney vortex) qui servent de moteur au mélange du scalaire passif propre au non-Newtonien. L’efficacité de mélange est augmentée en régime impinging par rapport au régime deflecting. Le shifting du pic de turbulence est observé uniquement en régime impinging. / For the simplicity in geometry by comparing it with other mixers in the industry, flows in T-junction configuration have been studied. More specifically, Direct Numerical Simulations is carried out using OpenFOAM on a convergent T-junction configuration with circular and rectangular cross-section. Both Newtonian and non-Newtonian fluids (Bird-Carreau model) are taken into account. Firstly, DNS data is compared to Nguyen’s experimental work on the circular T-junction at regime deflecting [1]. Good agreement between simlation and experiment is achieved. The organization of coherent structures is illustrated in laminar and turbulent for both Newtonian and non-Newtonian cases. Secondly, two flow regimes (deflecting and impinging) are simulated in a rectangular T-junction for the same Newtonian and non-Newtonian fluids. The existence of non-Newtonian coherent structures (e.g. kidney vortex ) is shown. These structures are regarded as essential mixing mechanism of passive scalar mixing. The mixing efficiency is increased in regime impinging compared to regime deflecting. The shifting of the turbulence peak is only observed in regime impinging.