Philosophiae Doctor - PhD / In this thesis, we describe linear codes over prime fields obtained from incidence designs of iterated line graphs of complete graphs Li(Kn) where i = 1, 2. In the binary case, results are extended to codes from neighbourhood designs of the line graphs Li+1(Kn) using certain elementary relations. Codes from incidence designs of complete graphs, Kn, and neighbourhood designs of their line graphs, L1(Kn) (the so-called triangular graphs), have been considered elsewhere by others. We consider codes from incidence designs of L1(Kn) and L2(Kn), and neighbourhood designs of L2(Kn) and L3(Kn). In each case, basic parameters of the codes are determined. Further, we introduce a family of vertex-transitive graphs Γn that are embeddable into the strong product L1(Kn)⊠  K2, of triangular graphs and K2, a class which at first sight may seem unnatural but, on closer look, is a repository of graphs rich with combinatorial structures. For instance, unlike most regular graphs considered here and elsewhere that only come with incidence and neighbourhood designs, Γn also has what we have termed as 6-cycle designs. These are designs in which the point set contains vertices of the graph and every block contains vertices of a 6-cycle in the graph. Also, binary codes from incidence matrices of these graphs have other minimum words in addition to incidence vectors of the blocks. In addition, these graphs have induced subgraphs isomorphic to the family Hn of complete porcupines (see Definition 4.11). We describe codes from incidence matrices of Γn and Hn and determine their parameters. / South Africa

The presence of both narcissism and social capital in the digital social networking site Facebook is altering the dynamic of relationship development. Therefore, the central research question directing this study is as follows: What role do narcissistic personality traits play in bridging social capital on Facebook? From this, two sub-questions are raised: 1) What are the motives for users to express narcissistic traits through Facebook? 2) How is narcissistic-motivated activity influencing social capital development through Facebook? Guiding this thesis are concepts of social tie relationships (as they apply to narcissism), and digital social networks. An exploratory study of in-depth interviews was utilized to conduct such research. A key objective in this thesis is understanding motive and purpose for generating social capital in an online environment. The findings from this study suggest Facebook is a facilitator for the expression of narcissistic traits. As a result, this is influencing the disconnected and questionable value of digital social capital.

Le manuscrit est constitué de deux parties indépendantes.Propriétés des Solutions de Viscosité des Equations Integro-Différentielles.Nous considérons des équations intégro-différentielles elliptiques et paraboliques non-linéaires (EID), où les termes non-locaux sont associés à des processus de Lévy. Ce travail est motivé par l'étude du Comportement en temps long des solutions de viscosité des EID, dans le cas périodique. Le résultat classique nous dit que la solution u(¢, t ) du problème de Dirichlet pour EID se comporte comme ?t Åv(x)Åo(1) quand t !1, où v est la solution du problème ergodique stationaire qui correspond à une unique constante ergodique ?.En général, l'étude du comportement asymptotique est basé sur deux arguments: la régularité de solutions et le principe de maximumfort.Dans un premier temps, nous étudions le Principe de Maximum Fort pour les solutions de viscosité semicontinues des équations intégro-différentielles non-linéaires. Nous l'utilisons ensuite pour déduire un résultat de comparaison fort entre sous et sur-solutions des équations intégro-différentielles, qui va assurer l'unicité des solutions du problème ergodique à une constante additive près. De plus, pour des équationssuper-quadratiques le principe de maximum fort et en conséquence le comportement en temps grand exige la régularité Lipschitzienne.Dans une deuxième partie, nous établissons de nouvelles estimations Hölderiennes et Lipschitziennes pour les solutions de viscosité d'une large classe d'équations intégro-différentielles non-linéaires, par la méthode classique de Ishii-Lions. Les résultats de régularité aident de plus à la résolution du problème ergodique et sont utilisés pour fournir existence des solutions périodiques des EID.Nos résultats s'appliquent à une nouvelle classe d'équations non-locales que nous appelons équations intégro-différentielles mixtes. Ces équations sont particulièrement intéressantes, car elles sont dégénérées à la fois dans le terme local et non-local, mais leur comportement global est conduit par l'interaction locale - non-locale, par exemple la diffusion fractionnaire peut donner l'ellipticité dans une direction et la diffusion classique dans la direction orthogonale.Visualisation et Restauration d'Images par Mouvements de CourbureLe rôle de la courbure dans la perception visuelle remonte à 1954, et on le doit à Attneave. Des arguments neurologiques expliquent que le cerveau humain ne pourrait pas possiblement utiliser toutes les informations fournies par des états de simulation. Mais en réalité on enregistre des régions où la couleur change brusquement (des contours) et en outre les angles et les extremas de courbure. Pourtant, un calcul direct de courbures sur une image est impossible. Nous montrons comment les courbures peuvent être précisément évaluées, à résolution sous-pixelique par un calcul sur les lignes de niveau après leur lissage indépendant.Pour cela, nous construisons un algorithme que nous appelons Level Lines (Affine) Shortening, simulant une évolution sous-pixelique d'une image par mouvement de courbure moyenne ou affine. Aussi bien dans le cadre analytique que numérique, LLS (respectivement LLAS) extrait toutes les lignes de niveau d'une image, lisse indépendamment et simultanément toutes ces lignes de niveau par Curve Shortening(CS) (respectivement Affine Shortening (AS)) et reconstruit une nouvelle image. Nousmontrons que LL(A)S calcule explicitement une solution de viscosité pour le le Mouvement de Courbure Moyenne (respectivement Mouvement par Courbure Affine), ce qui donne une équivalence avec le mouvement géométrique.Basé sur le raccourcissement de lignes de niveau simultané, nous fournissons un outil de visualisation précis des courbures d'une image, que nous appelons un Microscope de Courbure d'Image. En tant que application, nous donnons quelques exemples explicatifs de visualisation et restauration d'image : du bruit, des artefacts JPEG, de l'aliasing seront atténués par un mouvement de courbure sous-pixelique / The present dissertation has two independent parts.Viscosity solutions theory for nonlinear Integro-Differential EquationsWe consider nonlinear elliptic and parabolic Partial Integro-Differential Equations (PIDES), where the nonlocal terms are associated to jump Lévy processes. The present work is motivated by the study of the Long Time Behavior of Viscosity Solutions for Nonlocal PDEs, in the periodic setting. The typical result states that the solution u(¢, t ) of the initial value problem for parabolic PIDEs behaves like ?t Å v(x) Å o(1) as t ! 1, where v is a solution of the stationary ergodic problem corresponding to the unique ergodic constant ?. In general, the study of the asymptotic behavior relies on two main ingredients: regularity of solutions and the strong maximum principle.We first establish Strong Maximum Principle results for semi-continuous viscosity solutions of fully nonlinear PIDEs. This will be used to derive Strong Comparison results of viscosity sub and super-solutions, which ensure the up to constants uniqueness of solutions of the ergodic problem, and subsequently, the convergence result. Moreover, for super-quadratic equations the strong maximum principle and accordingly the large time behavior require Lipschitz regularity.We then give Lipschitz estimates of viscosity solutions for a large class of nonlocal equations, by the classical Ishii-Lions's method. Regularity results help in addition solving the ergodic problem and are used to provide existence of periodic solutions of PIDEs. In both cases, we deal with a new class of nonlocal equations that we term mixed integrodifferential equations. These equations are particularly interesting, as they are degenerate both in the local and nonlocal term, but their overall behavior is driven by the local-nonlocal interaction, e.g. the fractional diffusion may give the ellipticity in one direction and the classical diffusion in the complementary one.Image Visualization and Restoration by CurvatureMotionsThe role of curvatures in visual perception goes back to 1954 and is due to Attneave. It can be argued on neurological grounds that the human brain could not possible use all the information provided by states of simulation. But actually human brain registers regions where color changes abruptly (contours), and furthermore angles and peaks of curvature. Yet, a direct computation of curvatures on a raw image is impossible. We show how curvatures can be accurately estimated, at subpixel resolution, by a direct computation on level lines after their independent smoothing.To performthis programme, we build an image processing algorithm, termed Level Lines (Affine) Shortening, simulating a sub-pixel evolution of an image by mean curvature motion or by affine curvature motion. Both in the analytical and numerical framework, LL(A)S first extracts all the level lines of an image, then independently and simultaneously smooths all of its level lines by curve shortening (CS) (respectively affine shortening (AS)) and eventually reconstructs, at each time, a new image from the evolved level lines.We justify that the Level Lines Shortening computes explicitly a viscosity solution for the Mean CurvatureMotion and hence is equivalent with the clasical, geometric Curve Shortening.Based on simultaneous level lines shortening, we provide an accurate visualization tool of image curvatures, that we call an Image CurvatureMicroscope. As an application we give some illustrative examples of image visualization and restoration: noise, JPEG artifacts, and aliasing will be shown to be nicely smoothed out by the subpixel curvature motion.

The Swiss Free Electron Laser (SwissFEL) at the Paul Scherrer Institute is a national prestige project that will enable ground breaking new x-ray scattering experiments in areas such as biology, chemistry and physics. A plannedactivity is to generate possibility for x-ray diffraction under high pulsed magnetic fields to explore quantum mattermaterials. In fact, an entire beam line (CristallinaQ), dedicated to extreme sample environment (vacuum, electro-magnetic field, low temperature).This Master’s thesis project concerns the development of a magnet system for pulsed magnetic fields to be synchronised with the free electron laser pulses. The system is based on small-sized coils. This makes the systemtransportable and avoids the huge financial challenges and power requirements of the magnets at pulsed fields laboratories at Toulouse, Dresden or Tallahassee. Ultimately the magnet shall provide large pulsed fields of more than 30 T under conditions very similar to space, i.e. vacuum, low-temperature.The thesis presents the development of a complete coil manufacture and testing setup including a capacitor bank topower the magnet. With planned upgrades of the equipment, the coil manufacturing process is reaching reproduceable levels. I produce a first iteration of magnet coils. They follow a classical copper conductor design reinforcedwith an epoxy-Zylon matrix. During testing we produced 15 Tesla fields without degradation of the coils. At lastI analyse the observations from the tests and propose improvements and future steps for the further developmentof the magnet.

In dieser Arbeit wurden mit Hilfe von Transportmessungen – vor allem mit thermischem Transport bei sehr tiefen Temperaturen – intermetallische Seltenerdverbindungen untersucht. Diese Materialien sind oft durch starke elektronische Korrelationen gekennzeichnet, die zu neuartigen Eigenschaften führen. Um die Wechselwirkungen in den untersuchten Systemen zu beeinflussen, führten wir ein Magnetfeld als zusätzlichen Parameter ein. Damit untersuchten wir drei Fragestellungen. Im ersten Teil überprüften wir die Gültigkeit des Wiedemann-Franz-Gesetzes in YbRh2Si2. Dieses Material zeigt einen durch ein kleines Magnetfeld induzierten quantenkritischen Punkt, für dessen unkonventionelle Eigenschaften es noch keine allgemein etablierte mikroskopische Theorie gibt. Mit Hilfe des Wiedemann-Franz-Gesetzes haben wir untersucht, ob eine solche Theorie im Rahmen des Quasiteilchenbildes formuliert werden kann. Während wir eine Bestätigung für Magnetfelder abseits des quantenkritischen Punktes zeigen, ergibt unsere Analyse direkt am quantenkritischen Punkt eine Verletzung des Weidemann-Franz-Gesetzes. Dies hat weitreichende physikalische Folgen, da eine Verletzung den Zusammenbruch des Konzeptes von Quasiteilchen impliziert. In der zweiten Studie untersuchten wir die Kondogittersysteme YbRh2Si2 und CeRu2Si2 in Magnetfeldern mit Energien von der Größenordnung der Kondotemperatur. Beide Systeme zeigen bislang ungeklärte feldinduzierte Übergänge mit sehr unterschiedlichen Signaturen jedoch den selben Vorschlägen für deren Ursache: ein abrupter Zusammenbruch des Kondoeffekts oder ein Lifshitzübergang. Mit Thermokraft- und Widerstandsmessungen konnten wir für CeRu2Si2 zeigen, dass auch der thermische Transport kompatibel mit einem Lifshitzübergang ist. Ein globales Modell, das thermodynamische Größen mit einschließt, ist jedoch weiterhin nicht vorhanden. In YbRh2Si2 detektierten wir anstatt eines einzelnen, insgesamt drei Übergänge in höheren Magnetfeldern. Mithilfe einer sehr guten Übereinstimmung von renormalisierten Bandstrukturrechnungen mit unseren und früheren Experimenten, können wir die Entwicklung von YbRh2Si2 im Magnetfeld als Superposition von einer stetigen Unterdrückung des Kondoeffekts und drei Lifshitzübergängen beschreiben. Im dritten Projekt untersuchten wir den supraleitenden Ordnungsparameter von LaPt4Ge12. Während frühere Experimente auf konventionelle Supraleitung hindeuten, wird für das eng verwandte PrPt4Ge12 unkonventionelle und/oder Multiband-Supraleitung diskutiert. Resultate an der Substitutionsreihe LaxPr1-xPt4Ge12 suggerieren jedoch kompatible Ordnungsparameter für beide Verbindungen. Unsere Ergebnisse der spezifischen Wärme und der temperatur- und feldabhängigen Wärmeleitfähigkeit an LaPt4Ge12 sind kompatibel mit dem Modell konventioneller Supraleitung ohne Nullstellen im der supraleitenden Bandlücke. Die Abhängigkeit der Wärmeleitfähigkeit vom Feldwinkel zeigt unerwartet umfangreiche Oszillationsmuster. Während solche Oszillationen oft als Zeichen von Nullstellen in der Bandlücke interpretiert werden, konnten wir die meisten Frequenzen anderen Ursachen zuordnen. Eine sehr genaue Analyse von winkelabhängigen Messungen ist daher unabdingbar, um daraus Schlussfolgerungen für den Ordnungsparameter ziehen zu können.

I denna studie undersöktes regionala policydokument utifrån ett fokus på hållbar utveckling och förhållandet mellan hög tillväxt och förbättrad miljö. Det empiriska material utgjordes av Region Skånes tre regionala utvecklingsprogram, vilka behandlar hur myndigheten såg på regionens utveckling åren 1999–2004, 2004–2009 och 2009–2016. Studiens mål var att studera den diskursiva omdefinieringsprocessen av begreppet hållbar utveckling, genom att analysera hur detta relateras till och används i programmen. Metoden som användes var kritisk diskursanalys. Studien syftade till att synliggöra programmens diskursiva sammanhang och utveckla en förståelse för vilka synsätt och föreställningar som kan ses ligga till grund för dokumentens innehåll och utformning.Studien kom fram till att det fanns ingen tydlig förståelse kring hållbar utveckling i programmen utan det förekom yttringar av både starka och svaga hållbarhetsdiskurser. Resonemang kring ekologisk modernisering är dominerande, baserade på föreställningar om att miljöproblem kan lösas utan några stora samhällsförändringar. Denna diskurs presenterar attraktiva lösningar på eventuella motsättningar mellan hög tillväxt och förbättrad miljö, vilket möjliggör policydokument med visionära målbilder tillsammans med breda lösningar där målkonflikter och eventuella avvägningar inte belyses nämnvärt.Studiens teoretiska ramverk och metoden kritisk diskursanalys gav möjlighet att lyfta fram och belysa hur ekologisk moderniseringsdiskursen inkorporerar resonemang från tillväxtkritiska hållbarhetsdiskurser samtidigt som den marginaliserar och tar udden av dem. På så vis kan studien bidra till en vidare diskussion om olika sätt att förhålla sig till hållbar utveckling och konsekvenser av den ekologiska moderniseringens diskursiva dominans. / This study investigates regional policy documents with a focus on sustainable development and the relationship between high economic growth and an improved environment. The study’s empirical material is based on Region Skåne’s three regional development programs which put forward how the authority viewed development in the region for the years 1999–2004, 2004– 2009 and 2009–2016. The objective was to study the discursive process of redefining the concept of sustainable development by analysing how it is referred to and used in the programs. The method utilised was critical discourse analysis. The study aimed towards exposing the2programs’ discursive context and developing an understanding of the viewpoints underlying the documents’ contents.The study concluded that there was no clear understanding around sustainable development in the programs and there were statements of both strong and weak sustainable development discourse. Goal conflicts and eventually trade-offs were not particularly highlighted. Ecological modernisation was the dominating discourse as per the reasoning that environmental problems can be solved without any major societal changes. This discourse presents attractive solutions to potential conflicts which enables the policy document to provide visionary goals along with broad solutions. The study’s theoretical framework and the method critical discursive analysis allowed for the bringing forward and highlighting of how ecological modernisation incorporates reasonings from sustainable discourses critical of economic growth, at the same time marginalising and neutralising them. As a result, this study can contribute to the discussion of different ways of achieving sustainable development and the consequence of the domination of ecological modernisation discourse.

La thèse est portée essentiellement sur la stabilisation indirecte d’un système de deux équations des ondes couplées et sur la stabilisation frontière de poutre de Rayleigh.Dans le cas de la stabilisation d’un système d’équations d’onde couplées, le contrôle est introduit dans le système directement sur le bord du domaine d’une seule équation dans le cas d’un domaine borne ou à l’intérieur d’une seule équation mais dans le cas d’un domaine non borné. La nature du système ainsi couplé dépend du couplage des équations et de la nature arithmétique des vitesses de propagations, et ceci donne divers résultats pour la stabilisation polynomiale ainsi la non stabilité.Dans le cas de la stabilisation de poutre de Rayleigh, l’équation est considérée avec un seul contrôle force agissant sur bord du domaine. D’abord, moyennant le développement asymptotique des valeurs propres et des vecteurs propres du système non contrôlé, un résultat d’observabilité ainsi qu’un résultat de bornétude de la fonction de transfert correspondant sont obtenus. Alors, un taux de décroissance polynomial de l’énergie du système est établi. Ensuite, moyennant une étude spectrale combinée avec une méthode fréquentielle, l’optimalité du taux obtenu est assurée. / The thesis is driven mainly on indirect stabilization system of two coupled wave equations and the boundary stabilization of Rayleigh beam equation. In the case of stabilization of a coupled wave equations, the Control is introduced into the system directly on the edge of the field of a single equation in the case of a bounded domain or inside a single equation but in the case of an unbounded domain. The nature of thus coupled system depends on the coupling equations and arithmetic Nature of speeds of propagation, and this gives different results for the polynomial stability and the instability. In the case of stabilization of Rayleigh beam equation, we consider an equation with one control force acting on the edge of the area. First, using the asymptotic expansion of the eigenvalues and vectors of the uncontrolled system an observability result and a result of boundedness of the transfer function are obtained. Then a polynomial decay rate of the energy of the system is established. Then through a spectral study combined with a frequency method, optimality of the rate obtained is assured.

This essay examines and analyzes the debate between David Chalmers and Daniel Dennett about the nature of consciousness and how to proceed to explain its existence. They are two of the biggest names of philosophy of mind today and have been on opposite sides of the debate since the nineties. Chalmers has long advocated a modern dualistic view of consciousness while Dennett's theories move in a more physicalist and functionalist direction. Today, Chalmers calls himself a realist as a clear opposite to Dennett's illusionism. The essay begins with a short summary of the history of modern philosophy of mind and a presentation of Chalmers and Dennett. Then it goes into some of their most noted older theories and arguments and move on to two of the most famous thought experiments of philosophy of mind before going into their most recent theories and work. It concludes with summary of their development and with an analysis of the sustainability and significance of their theories for the development of the debate today together with some personal reflections.

This paper deals about AdaBoost algorithm, which is used to create a strong classification function using a number of weak classifiers. We familiarize ourselves with modifications of AdaBoost, namely Real AdaBoost, WaldBoost, FloatBoost and TCAcu. These modifications improve some of the properties of algorithm AdaBoost. We discuss some properties of feature and weak classifiers. We show a class of tasks for which AdaBoost algorithm is applicable. We indicate implementation of the library containing that method and we present some tests performed on the implemented library.

A standard problem in mathematical finance is the calculation of the price of some financial derivative such as various types of options. Since there exists analytical solutions in only a few cases it will often boil down to estimating the price with Monte Carlo simulation in conjunction with some numerical discretization scheme. The upside of using what we can call standard Monte Carlo is that it is relative straightforward to apply and can be used for a wide variety of problems. The downside is that it has a relatively slow convergence which means that the computational cost or complexity can be very large. However, this slow convergence can be improved upon by using Multilevel Monte Carlo instead of standard Monte Carlo. With this approach it is possible to reduce the computational complexity and cost of simulation considerably. The aim of this thesis is to introduce the reader to the Multilevel Monte Carlo method with applications to European and Asian call options in both the Black-Scholes-Merton (BSM) model and in the Heston model. To this end we first cover the necessary background material such as basic probability theory, estimators and some of their properties, the stochastic integral, stochastic processes and Ito’s theorem. We introduce stochastic differential equations and two numerical discretizations schemes, the Euler–Maruyama scheme and the Milstein scheme. We define strong and weak convergence and illustrate these concepts with examples. We also describe the standard Monte Carlo method and then the theory and implementation of Multilevel Monte Carlo. In the applications part we perform numerical experiments where we compare standard Monte Carlo to Multilevel Monte Carlo in conjunction with the Euler–Maruyama scheme and Milsteins scheme. In the case of a European call in the BSM model, using the Euler–Maruyama scheme, we achieved a cost O(ε-2(log ε)2) to reach the desired error in accordance with theory in comparison to the O(ε-3) cost for standard Monte Carlo. When using Milsteins scheme instead of the Euler–Maruyama scheme it was possible to reduce the cost in terms of the number of simulations needed to achieve the desired error even further. By using Milsteins scheme, a method with greater order of strong convergence than Euler–Maruyama, we achieved the O(ε-2) cost predicted by the complexity theorem compared to the standard Monte Carlo cost of order O(ε-3). In the final numerical experiment we applied the Multilevel Monte Carlo method together with the Euler–Maruyama scheme to an Asian call in the Heston model. In this case, where the coefficients of the Heston model do not satisfy a global Lipschitz condition, the study of strong or weak convergence is much harder. The numerical experiments suggested that the strong convergence was slightly slower compared to what was found in the case of a European call in the BSM model. Nevertheless, we still achieved substantial savings in computational cost compared to using standard Monte Carlo.