La coordination des activités dans une chaîne logistique a suscité récemment beaucoup d'attention dans larecherche de gestion. Dans une chaîne logistique typique, des produits finis sont produits et transportés pour êtrestockage temporairement ou arriver directement chez clients. Pour réaliser la représentation opérationnelleoptimale, la coordination et l'intégration de la production, de la livraison, et du stockage devient très importante.L'étude récente a considéré le coût de stockage de client avec le coût fixe de transport ou la taille fixe des lots, cequi est irréaliste.Dans cette thèse, nous étudions la coordination de traitement des produits en lots et l'ordonnancement des lots, quiinclut la coordination du traitement en lots des produits dans les groupes après l'étape de production,l'ordonnancement des lots après les productions exigent la livraison du fournisseur ainsi que le stockage desproduits aux clients. Ce travail focalise sur les cas du simple-fournisseur/plusieurs-clients et le cas de simplefournisseur/plusieurs-transporteurs. Pour le premier scénario avec plusieurs-clients, deux modèles illustrent letransfert des lots aux clients. Dans le premier modèle, nous avons considéré un simple-fournisseur/plusieurs-clientsavec un transporteur disponible pour servir les clients sans considération du problème de tournée de véhicule. Puis,dans le deuxième modèle, nous avons considéré un simple-fournisseur/plusieurs-clients avec plusieurs transportersdisponibles pour servir les clients. Différentes hypothèses sont proposées et comparées dans le dernier chapitre.Pour ce qui concerne le deuxième scénario, nous avons étudié le cas du simple-fournisseur avec plusieurstransporteurs disponibles pour servir un seul client. Dans ce scénario, des modèles avec les véhicules homogèneset hétérogènes sont étudiés. Tout le coût du système est calculé en additionnant de tout le coût de la livraison et destockage pour les différents clients et transporteurs qui se sont dans le système à étudier. Le nombre des produitsdans les lots peut être inégal et les lots sont limités seulement par la capacité du transporteur utilisé. Le coût destockage chez les clients dépend de chaque client, la distance entre le fournisseur et leurs clients dépend del'emplacement de client, qui est le cas du coût de livraison également qui dépend de l'emplacement du client. Dansle cas des multi transporteurs, le coût de livraison dépend du transporteur utilisé.Dans chaque modèle, nous présentons ce qui suit : procédures de solution pour résoudre chaque modèle, plusieursexemples numériques pour soutenir des résultats mathématiques et pour clarifier le problème, et comparaisons desperformances parmi différents résultats. La future extension de cette recherche peut considérer des contraintes detemps et de coût de chargement dans l'étape de production, la considération du tourné de véhicule avec un cout destockage chez les clients. / The coordination of logistics activities in a supply chain has recently received a lot of attention in operationsmanagement research. In a typical supply chain, finished products are produced and either shipped to be temporarystorage or arrived directly on time to the customers. To achieve optimal operational performance, the coordinationand integration of production, delivery, and storage is an important consideration. The recent study consideredcustomer storage cost with fixed transportation cost or fixed batch size, which is unrealistic. In this thesis, we studythe coordinate of batching and scheduling activities, which includes the coordination of batching of products inbatches after the production stage, the coordination of scheduling, customer(s) orders which require the deliveryfrom the supplier, and the storage of products at the customer(s). This study focus on single-supplier/multi-customerscenario and single-supplier/multi-transporter scenario. For the first scenario with multi-customer, two modelsillustrate the transferring of batches to the customer. Where in the first model, we considered a singlesupplier/ multicustomerwith one capacitated transporter available to serve the customers without the vehicle routingconsideration. Then, in the second model, we considered a single-supplier/multi-customer with multi-transportavailable to serve the customers. In this case different assumption is proposed and compared in the last chapter.Concerning the second scenario, we studied the case of single-supplier with multi-transporter available to serve asingle customer. In this scenario, models with homogeneous and heterogeneous vehicles are studied. The totalsystem cost is calculated by summing the total delivery and storage cost for different customers and transporters inthe system. The number of products by batch is unequal and they are limited only by the capacity of the transporterused. The storage cost of the customers depends on the customer destination, the distance between the supplierand their customers depends on the customer location, which is the case of the delivery cost also which depends onthe customer¿s location. In the case of the multi-transporters, the delivery cost depends on the transporter used.In each model, we present the following: solution procedures to solve each model, many numerical examples tosupport mathematical findings and to clarify the problem under study, and performance comparisons amongdifferent findings. The future extension of this research may involve considering setup time and cost constraints inthe production stage, the vehicle routing consideration with inventory in the multi-customer case.

Orientador: Antonio Carlos Ferreira Seridonio / Resumo: Estudou-se teoricamente um modelo composto por um fio de Kitaev na fase topológica com dois pontos quânticos (QDs - Quantum Dots), um em cada extremidade do nanofio. Desta forma, dois casos foram factíveis de análise, um deles com os estados ligados de Majorana (MBSs - Majorana Bound States) das bordas do fio acoplados a um único QD e o segundo em que se tem ambos os MBSs acoplados aos dois QDs. Para a primeira situação três condições foram estudadas, nas quais se verificou, na primeira, os perfis de férmions de Majorana não locais, dados pelo acoplamento entre o MBS e o QD mais próximo e, nas outras duas condições, dois perfis relacionados aos acoplamentos dos dois MBSs a um QD, em que se considerou também a superposição entre os MBS. Estes dois perfis são denominados de bowtie e diamond, já conhecidos na literatura, possuindo também experimentos que validam suas manifestações. No segundo caso, em que se tem o acoplamento dos dois MBSs aos dois QDs e que se considerou também amplitudes de superposição entre os férmions de Majorana, investigou-se a manifestação de estados moleculares mediados por tais férmions, pois o transporte eletrônico entre os QDs, no sistema proposto, se dá por meio do nanofio. Constatou-se padrões condizentes a níveis moleculares ligante e antiligante nas assinaturas dos estados ligados de Andreev (ABSs), originários da superposição dos MBSs, assim como nos níveis dos QDs que foram desdobrados após a formação molecular. / Mestre

This essay seeks to explore the relation between Crimson Bound and the fairy tale from which it derives from. Today, it is common to use fairy tales as a base for new literature, movies and tv-series and therefore it is interesting to study these new additions to our media. By applying Vladimir Propps extensive study of fairy tales to Rosamund Hodges Crimson Bound and the Brothers Grimms Little Red Cap I hope to come to an understanding of the differences and similarities that these two holds. Through this analysis I conclude that Hodges utilizes the functions that Propp states are specific to the fairy tale genre. I also conclude that, although Hodges closely follow the initial structure of Little Red Cap, she deviates from the fairy tale towards the ending. Besides the interesting similarities and the effect of the differences, the roles of the protagonist and the antagonist stands out. Therefore, a portion of this essay delves deeper into how the adaption to the fantasy genre affect these roles as well as how the relationship between then protagonist and antagonist alters due to this.

Indoor positioning is desired in many areas for various reasons, such as positioning products in industrial environments, hospital equipment or firefighters inside a building on fire. One even tougher situation where indoor positioning can be useful is locating a specific object on a shelf in a commercial setting. This thesis aims to investigate and design different network deployment strategies in an indoor environment in order to achieve both high position estimation accuracy and availability. The investigation considers the two positioning techniques downlink time difference of arrival, DL-TDOA, and round trip time, RTT. Simulations of several deployments are performed in two standard scenarios which mimic an indoor open office and an indoor factory, respectively. Factors having an impact on the positioning accuracy and availability are found to be deployment geometry, number of base stations, line-of-sight conditions and interference, with the most important being deployment geometry. Two deployment strategies are designed with the goal of optimising the deployment geometry. In order to achieve both high positioning accuracy and availability in a simple, sparsely cluttered environment, the strategy is to deploy the base stations evenly around the edges of the deployment area. In a more problematic, densely cluttered environment the approach somewhat differs. The proposed strategy is now to identify and strategically place some base stations in the most cluttered areas but still place a majority of the base stations around the edges of the deployment area. A robust positioning algorithm is able to handle interference well and to decrease its impact on the positioning accuracy. The cost, in terms of frequency resources, of using more orthogonal signals may not be worth the small improvement in accuracy and availability.

Dans un graphe non orienté, le Problème de Coloration de Graphe (PCG) consiste à assigner à chaque sommet du graphe une couleur de telle sorte qu'aucune paire de sommets adjacents n'aient la même couleur et le nombre total de couleurs est minimisé. DSATUR est un algorithme exact efficace pour résoudre le PCG. Un de ses défauts est qu'une borne inférieure est calculée une seule fois au noeud racine de l'algorithme de branchement, et n'est jamais mise à jour. Notre nouvelle version de DSATUR surpasse l'état de l'art pour un ensemble d'instances aléatoires à haute densité, augmentant significativement la taille des instances résolues. Nous étudions trois formulations PLNE pour le Problème de la Somme Chromatique Minimale (PSCM). Chaque couleur est représentée par un entier naturel. Le PSCM cherche à minimiser la somme des cardinalités des sous-ensembles des sommets recevant la même couleur, pondérés par l'entier correspondant à la couleur, de telle sorte que toute paire de sommets adjacents reçoive des couleurs différentes. Nous nous concentrons sur l'étude d'une formulation étendue et proposons un algorithme de Branch-and-Price. / Given an undirected graph, the Vertex Coloring Problem (VCP) consists of assigning a color to each vertex of the graph such that two adjacent vertices do not share the same color and the total number of colors is minimized. DSATUR is an effective exact algorithm for the VCP. We introduce new lower bounding techniques enabling the computing of a lower bound at each node of the branching scheme. Our new DSATUR outperforms the state of the art for random VCP instances with high density, significantly increasing the size of solvable instances. Similar results can be achieved for a subset of high density DIMACS instances. We study three ILP formulations for the Minimum Sum Coloring Problem (MSCP). The problem is an extension of the classical Vertex Coloring Problem in which each color is represented by a positive natural number. The MSCP asks to minimize the sum of the cardinality of subsets of vertices receiving the same color, weighted by the index of the color, while ensuring that vertices linked by an edge receive different colors. We focus on studying an extended formulation and devise a complete Branch-and-Price algorithm.

La croissance exponentielle des données personnelles, et leur mise à disposition sur la toile, a motivé l’émergence d’algorithmes d’apprentissage de préférences à des fins de recommandation, ou d’aide à la décision. Les réseaux de préférences conditionnelles (CP-nets) fournissent une structure compacte et intuitive pour la représentation de telles préférences. Cependant, leur nature combinatoire rend leur apprentissage difficile : comment apprendre efficacement un CP-net au sein d’un milieu bruité, tout en supportant le passage à l’échelle ?Notre réponse prend la forme de deux algorithmes d’apprentissage dont l’efficacité est soutenue par de multiples expériences effectuées sur des données réelles et synthétiques.Le premier algorithme se base sur des requêtes posées à des utilisateurs, tout en prenant en compte leurs divergences d’opinions. Le deuxième algorithme, composé d’une version hors ligne et en ligne, effectue une analyse statistique des préférences reçues et potentiellement bruitées. La borne de McDiarmid est en outre utilisée afin de garantir un apprentissage en ligne efficace. / The rapid growth of personal web data has motivated the emergence of learning algorithms well suited to capture users’ preferences. Among preference representation formalisms, conditional preference networks (CP-nets) have proven to be effective due to their compact and explainable structure. However, their learning is difficult due to their combinatorial nature.In this thesis, we tackle the problem of learning CP-nets from corrupted large datasets. Three new algorithms are introduced and studied on both synthetic and real datasets.The first algorithm is based on query learning and considers the contradictions between multiple users’ preferences by searching in a principled way the variables that affect the preferences. The second algorithm relies on information-theoretic measures defined over the induced preference rules, which allow us to deal with corrupted data. An online version of this algorithm is also provided, by exploiting the McDiarmid's bound to define an asymptotically optimal decision criterion for selecting the best conditioned variable and hence allowing to deal with possibly infinite data streams.

The subject of the present thesis are some aspects of impurities affecting mesoscopic systems with regard to their topological properties and related effects like Majorana fermions and quantized conductance. A focus is on two-dimensional systems including both topological insulators and superconductors. First, the question of whether individual nonmagnetic impurities can induce zero-energy states in time-reversal invariant superconductors from Altland-Zirnbauer (AZ) symmetry class DIII is addressed, and a class of symmetries which guarantee the existence of such states for a specific value of the impurity strength is defined. These general results are applied to the time-reversal invariant p-wave phase of the doped Kitaev-Heisenberg model, where it is also demonstrated how a lattice of impurities can drive a topologically trivial system into the nontrivial phase. Second, the result about the existence of zero-energy impurity states is generalized to all AZ symmetry classes. This is achieved by considering, for general Hamiltonians H from the respective symmetry classes, the “generalized roots of det H”, which subsequently are used to further explore the opportunities that lattices of nonmagnetic impurities provide for the realization of topologically nontrivial phases. The 1d Kitaev chain model, the 2d px + ipy superconductor, and the 2d Chern insulator are considered to show that impurity lattices generically enable topological phase transitions and, in the case of the 2d models, even provide access to a number of phases with large Chern numbers. Third, elastic backscattering in helical edge modes caused by a magnetic impurity with spin S and random Rashba spin-orbit coupling is investigated. In a finite bias steady state, the impurity induced resistance is found to slightly increase with decreasing temperature for S > 1/2. Since the underlying backscattering mechanism is elastic, interference between different scatterers can explain reproducible conductance fluctuations. Thus, the model is in agreement with central experimental results on edge transport in 2d topological insulators.

Let M be a finite set of random uniformly distributed points lying in a unit cube. Every four points from M make a tetrahedron and the tetrahedron can either contain some of the other points from M, or it can be empty. This diploma thesis brings an upper bound of the expected value of the number of empty tetrahedra with respect to size of M. We also show how precise is the upper bound in comparison to an approximation computed by a straightforward algorithm. In the last section we move from the three- dimensional case to a general dimension d. In the general d-dimensional case we have empty d-simplices in a d-hypercube instead of empty tetrahedra in a cube. Then we compare the upper bound for d-dimensional case to the results from another paper on this topic. 1

This study aimed to collate and analyse academic literature with regards to possible African perspectives on psychological distress. The purpose of conducting the literature review was to explore thirty years of critical arguments supporting and refuting an African perspective on psychopathology. Literature (e.g. Bhugra&Bhui, 1997) appeared to suggest that some of the relatively recent views regarding psychopathology fail to adequately address psychological distress as it presents in Africa. A systematic literature review was selected as the methodology for this study, and the specific method of the review was research synthesis (Gough, 2004; Popay, 2005). Reviewed literature was sourced between the years 1980 and 2010. The theoretical point of departure was integrative theory, thus falling within the postpostmodern framework. As such, literature regarding psychological theory formed a substantial part of the research, including literature relating to psychodynamic theory, cognitive-behavioural theory, postmodernism, phenomenology, existentialism, critical theory, and systemic patterning (Becvar&Becvar, 1996). These theories formed part of the analysis, thereby allowing contextual analysis as the interpretive method. The review’s themes highlighted the following outcomes: current psychiatric nosology employed a universalistic approach to diagnosis and intervention, thus limiting cultural conceptions of mental illness; holistic intervention requires the inclusion of traditional epistemological tenets; collaboration between modern practitioners and traditional healers would probably better meet the patient’s needs; and that culture-fit assessment and treatment often indicated improved prognosis. The outcomes evidenced the operation of an African perspective on psychopathology. In fact, much of the reviewed literature also suggested culture-contextual perspectives on psychopathology. Furthermore, the way in which lack of cultural coherence appears to exist between patients and some clinicians suggested that diagnostic flaws may be a relatively frequent occurrence. Potential benefits of the investigation include increased awareness that culture-related conceptualisation be further explored in the clinical field; that future researchers use the current review as a foundational reference for primary investigations; that contemporary clinical classificatory systems be reviewed in terms of cultural applicability; and that clinicians reconsider the diagnostic process in terms of culture-fit manifestations of psychopathology. / Thesis (PhD)--University of Pretoria, 2012. / Psychology / unrestricted

In this thesis, we first propose a new scalar auxiliary variable (SAV) approach for general dissipative nonlinear systems. This new approach is half computational cost of the original SAV approach, can be extended to high order unconditionally energy stable backward differentiation formula (BDF) schemes and not restricted to the gradient flow structure. Rigorous error estimates for this new SAV approach are conducted for the Allen-Cahn and Cahn-Hilliard type equations from the BDF1 to the BDF5 schemes in a unified form. As an application of this new approach, we construct high order unconditionally stable, fully discrete schemes for the incompressible Navier-Stokes equation with periodic boundary condition. The corresponding error estimates for the fully discrete schemes are also reported. Secondly, by combining the new SAV approach with functional transformation, we propose a new method to construct high-order, linear, positivity/bound preserving and unconditionally energy stable schemes for general dissipative systems whose solutions are positivity/bound preserving. We apply this new method to second order equations: the Allen-Cahn equation with logarithm potential, the Poisson-Nernst-Planck equation and the Keller-Segel equations and fourth order equations: the thin film equation and the Cahn-Hilliard equation with logarithm potential. Ample numerical examples are provided to demonstrate the improved efficiency and accuracy of the proposed method.