Internet roku 2015 se potýká s problémy, které jsou důsledky špatného designu pojmenovávání a adresování v TCP/IP a jež mají přeneseny vliv i na škálovatelnost směrování. Problémy jako růst páteřních směrovacích tabulek, neefektivní multihoming sítí či mobilita zařízení a mnohé další zadávají k otázce, jestli není třeba architekturu Internetu pozměnit. V teoretické části je kvantifikován dopad problémů, možná řešení a zejména je formálně definována teorie kompilujicí poznatky významných publikací zabývajících se problematikou pojmenování, adresování a směrování v počítačových sítí. Tato práce se zabývá dvěma konkrétními technologiemi, jež mají ambicí Internet měnit - Locator/Id Separation Protocol a Recursive InterNetwork Architecture. Výstupem práce jsou vylepšení funkcionality obou výše zmíněných technologií. Za účelem praktického ověření dopadů našeho výzkumu jsou vyvinutý a popsány nové simulační modely pro OMNeT++, které jsou věrné úrovni detailu popisu ze specifikací.

For an education system to function effectively it is important that its planning functions are executed effectively and efficiently. Among others this implies that the system must know what the teacher supply and demand is and how it will change in time. If the teacher supply and demand is known it could result in sound intervention strategies being developed and implemented. Education planners will be able to plan for the number of bursaries to be awarded and in which subject fields; it will be known how many foreign teachers to employ and for which subjects. This is the basic rationale that underpins this study. This study explored the problem of teacher demand and supply in the Further Education and Training (FET) phase (Grades 10 to 12) in South Africa and offers a critical analysis of strategies adopted by Provincial Education Departments in an endeavour to diminish the demand for teachers, specifically for Mathematics and Science, in rural and poor schools. Initially the study involved a secondary data analysis to extrapolate the demand and supply of teachers in Mathematics and Science over the next ten years. The first key finding of the study was that the data needed for such an analysis does not exist in any reliable form that would facilitate the development of such a projection. What the study had to rely on was anecdotal evidence that suggests that a shortage of Mathematics and Science teachers does exist and that posts are often filled by unqualified and under-qualified staff. In the second phase of the research in which the study explored the effectiveness of strategies developed to address the shortage of Mathematics and Science teachers, a qualitative research approach was adopted within a descriptive interpretive design. The views and opinions of human resource managers responsible for post provisioning in schools were explored through in-depth interviews to understand the types of strategy adopted by the provinces, their potential to alleviate the problem of Mathematics and Science teacher shortage in Grades 10 to 12, their success, challenges and factors internal to the Department of Education that may deter Provincial Education Departments from achieving their objectives. The findings revealed that Provincial Education Departments (PEDs) do take heed of strategies developed by the national Department of Basic Education (DBE). However implementation is far removed from the original intention and no significant impact results. Although the reasons are not always obvious from this study, a few important aspects did emerge. First, the strategy developed may not be popular with a particular province - employing foreign teachers is a case in point. Secondly, focusing on just a number of schools to improve their results (e.g. as with the Dinaledi schools) may meet with resistance from educators and teachers’ unions. Thirdly, creating bursaries for initial teacher education in certain key areas can only be successful if the number of teachers in need is known. Finally, even the best strategies are doomed if post provisioning and appointment of staff are dealt with by different stakeholders. Based on the findings, it is recommended that both the DBE and PEDs ensure that quality education management information is collected and maintained. Information that is reliable and accurate will inform planning and key decisions to ensure that the supply of teachers is based on a specific need. As such, deficiencies in skills that are in short supply such as Science and Mathematics can be averted and better opportunities can be created for new teacher graduates. While an improved performance of learners in these subjects is requisite for related study fields at universities, the Dinaledi schools must be adequately supported and such a model applied to other schools. The employment of foreign teachers on short-term contracts does not create stability in schools, therefore, their employment must be standardised. Significantly, retention in rural and poor schools is a problem since they struggle to attract quality teachers; for that reason teacher incentives are indispensable. Making a declaration for unqualified and under-qualified teachers to acquire professional teaching qualifications and subsequently discontinue such appointments, will raise the standard of teaching and learning in schools. Rather, databases of unemployed qualified teachers could be maintained and such information made accessible to school principals. In the absence of reliable data that can indicate teacher qualification and specialisation versus subject taught, the extent to which Mathematics and Science are taught by unqualified and under-qualified teachers as well as out-of-specialisation teaching, is not known. However, poor pass rates in these subjects at the exit point of the schooling system (Grade 12) attest to the lack of appropriately skilled teacher workforce. Therefore, if Mathematics and Science specialisation is required, then strategies being implemented by the DBE and PEDs must have a clear purpose to address this shortage. / Thesis (PhD)--University of Pretoria, 2014. / lk2014 / Education Management and Policy Studies / PhD / Unrestricted

La nanotechnologie a pris un rôle clé dans le développement technologique actuel de façon extrêmement grande et interdisciplinaire. L'utilisation de nanofils dans la construction de structures/dispositifs plus complexe peut être entrevue en raison de sa polyvalence. Comprendre la fabrication de nanofils et être capable de les caractériser est extrêmement important pour ce développement. Des dispositifs à base de nanofils semi-conducteurs et ferromagnétiques ont été étudiés dans cette thèse, abordant les techniques de croissance et d'adressage pour des caractérisations électroniques et structurelles, et pour des développements à grande échelle pour des applications industrielles. Les nanofils de cobalt ont été électro déposés à différents pH permettant d'associer le pH de la solution à la caractérisation de la structure cristalline. Les nanofils de semiconducteurs ont été crus par CVD. L'adressage et l'alignement des nanofils ont été faits par diélectrophorèse couplé avec l'assemblage capillaire. Pour caractériser les nanofils, des techniques de lithographie optique et électronique ont été utilisés pour la fabrication des contacts. Une étude d'interface matériaux semiconducteurs/siliciure a été réalisée démontrant que les valeurs de barrière Schottky sont différentes entre des nanofils de silicium et des matériaux massifs. Dans le cas de nanofils InAs la barrière est imperceptible et il a été constaté que le fil de ZnO était de type p. Les applications ont démontrées différents dispositifs, tels que les transistors, les vannes de spin, capteurs de gaz, de l'humidité et de la lumière. Dans le cadre de vannes de spin, la caractérisation de l'interface semiconducteur/ferromagnétique a permis d'associer la valeur de la hauteur de barrière de Schottky à l'épaisseur de SiO2, qui agit comme une barrière à effet tunnel. Grâce aux mesures de transistors à effet de champ (FET) , nous avons pu identifier le type de porteurs de charge pour chaque matériau, extraire leur mobilité, la tension de seuil... Les capteurs ont été fabriqués à base de nanofils en Si, InAs, et ZnO, afin d'être utilisés comme capteurs de lumière, l'humidité et les gaz. Cette thèse propose une amélioration des technologiques actuelles d'adressage de nanostructures et l'utilisation des propriétés à l'échelle nanométrique pour des dispositifs plus efficaces et une large applicabilité, fournissant la base pour de futures études et les réalisations pratiques des nanosciences et des nanotechnologies. / Nanotechnology is at the center of nowadays technologies in an increasing and very interdisciplinary manner. Sticking together the manufacturing and characterization of the nano-devices and their constituent nanostructures are keys for the development of the field. This thesis covered studies of ferromagnetic (Co) and semiconductors nanowires (Si, InAs and ZnO) based nanodevices. Nanowires growing and correct addressing techniques were studied for measurements and characterizations set ups and for large-scale industrial applications possibilities. The growing techniques were electrodeposition and CVD. Different pHs were used for the solutions in the case of the Co nanowires growing that were, than, connected by means of electronic lithography. The resulting measurements enabled us to associate the pH to the crystalline structure characterization. The nanowires addressing was made using the dieletrophoresis technique coupled to capillary assembly and also by contacting the isolated nanowire by means of electronic lithography. The contact made in the nanowire was favored by the silicidation technique. For this two different materials, Pt and Ni, compatible with the CMOS technology. A deep study of the interface semiconductor/silicidation was performed and the Schottky Barrier of Si nanowires was verified to be smaller than the barrier in the bulk form of Si. In the InAs nanowires case an imperceptible barrier was found. The ZnO nanowires were found to be of p-type. The following devices were manufactured: top/back-gate transistors, lateral spin valves (local and non-local valves) and multilayer-nanowires based spin valves (local valves). The semiconductor nanowires sensors (gas, humidity and luminosity) were also manufactured and tested. In the spin valves context the interface semiconductor/ferromagnetic material was studied in order to associate the Schottky Barrier height to the SiO2 width that acts as a tunnel barrier. From the semiconductors nanowires based field effect transistors (FETs) measurements it was possible to verify the charge carriers type for each different material, to extract its mobility, threshold voltage and others. The manufactured sensors were made of Si, InAs and ZnO nanowires and the main aim was to use them as gas, humidity and luminosity sensors. The ZnO nanowires have been seen to be light sensitive whereas the Si and InAs nanowires responded to the presence of humidity and of pollutant gases, e.g. the NO2.

No description available.

Le routage dans Internet est basé sur des tables dites de routage, formées de blocs d’adresses IP. Cependant, la construction et la maintenance de telles tables de routage nécessitent l’utilisation de protocoles complexes qui ne passent pas à l’échelle en termes de mémoire et d’utilisation CPU. De plus, l’expérience montre que le plan d’adressage IP est insuffisant, car la sémantique d’une adresse IP est à la fois un identificateur et un localisateur. Dans nos travaux, nous proposons un système de réseau recouvrant pair-à-pair libre de toute contrainte topologique et utilisant des coordonnées virtuelles prises dans le plan hyperbolique nommé CLOAK (Covering Layer Of Abstract Knowledge en anglais). Les schémas de routages locaux basés sur des coordonnées virtuelles extraites du plan hyperbolique ont suscité un intérêt considérable ces dernières années. Dans cette thèse, nous proposons une nouvelle approche pour saisir le potentiel de la géométrie hyperbolique. L’objectif est de construire un système extensible et fiable pour créer et gérer des réseaux recouvrants dans Internet. Le système est implémenté comme une infrastructure pair-à-pair structuré basé sur les protocoles de la couche transport entre les pairs. Quant à l’organisation des données dans l’espace virtuel, nous employons la réplication pour améliorer la disponibilité et l’accessibilité des objets de l’overlay potentiellement instable. Nous avons implémenté et évalué différentes méthodes de réplication (réplication radiale, réplication circulaire).A l’aide de simulations, nous évaluons notre proposition à travers un certain nombre de métriques et nous montrons que les réseaux recouvrants pair-à-pair basés sur la géométrie hyperbolique ont de bonnes performances par rapport aux autres DHT existantes tout en introduisant flexibilité et robustesse dans les réseaux recouvrants dynamiques. / Internet routing is based on forwarding tables populated by blocks of IP addresses. However, the construction and maintenance of such tables require the use of complex routing protocols that are typically not scalable in terms of memory and CPU usage. Moreover, experience shows that the IP addressing plane is insufficient due to the semantic of an IPaddress being both an identifier and a locator. In this paper, we propose a P2P overlay system of freed topology and using virtual coordinates taken from the hyperbolic plane named CLOAK(Covering Layer Of Abstract Knowledge en anglais). Local knowledge routing schemes based on virtual coordinates taken from the hyperbolic plane have attracted considerable interest in recent years. In this thesis we propose a new approach for seizing the power of the hyperbolic geometry. We aim at building a scalable and reliable system for creating and managing overlay networks over the Internet. The system is implemented as a structured peer-to-peer infrastructure based on the transport layer connections between the peers. Concerning data organisation in the virtual space, we use replication strategy for improve overlay objects disponibilty and accessibility in context potentially unstable. We have implemented and evaluated various replication methods (radial replication, circular replication). Using simulations, we assess our proposal across a certain number of metric and show that overlay Peer-to-Peer network based on the hyperbolic geometry have good performances in comparison with other existent DHT while introducing suppleness and robustness in the dynamic overlay network.

Les réseaux de capteurs sans fil qui conviennent pour vaste domaine d’applications, constituent une solution prometteuse qui répond à toute exigence de surveillance continue. L’autonomie énergétique des nœuds constitue un facteur de vulnérabilité qui influe directement leur longévité et la capacité du réseau à assurer longuement la couverture d’une zone géographique d’intérêt. La gestion de consommation énergétique représente la seule approche pour accroître la durée de vie de ces réseaux et leur conférer une autonomie raisonnable. Des solutions logicielles proposées à travers les protocoles MAC, apportent des améliorations significatives à la minimisation de la dépense énergétique des nœuds. Elles permettent de réduire les périodes d’écoute du canal qui, représente l’opération la plus coûteuse en termes d’énergie dans le fonctionnement des nœuds de capteurs sans fil. Néanmoins, se limiter à ces solutions n’est pas suffisant pour garantir une longévité acceptable. La seule méthode pour optimiser la conservation d’énergie dans les RCSFs est de mettre chaque nœud constamment en mode faible puissance et d’utiliser un mécanisme de télé-réveil à travers des signaux de réveil. Cela implique, l’utilisation de circuits de réveil de faible consommation qui assurent la surveillance de canal et qui déclenchent le réveil des nœuds uniquement à chaque fois qu’événement d’intérêt se produit. Dans ce contexte, une quantité importante de travaux ont proposés l’utilisation d’un mécanisme d’adressage (adresses MAC ou d’autres informations binaires), pour permettre aux nœuds non concernés de retourner rapidement dans son état de sommeil. Cette démarche est intéressante, mais implique toutefois une dépense énergétique non négligeable, liée à la réception et au traitement des informations d’adresse au niveau de tous les nœuds. La solution la plus efficace énergétiquement serait l’utilisation d’une autre forme d’adresse. Cette thèse s’inscrit dans le contexte de minimisation de la consommation énergétique des RCSFs par la mise en œuvre d’un adressage qui permet aux nœuds de recevoir et de traiter les signaux de réveil, sans allumer leur module de communication principal. Il s’agit pour nous de supprimer la dépense énergétique liée à l’allumage du module RF et à la réception de paquets d’adresse, en se tournant vers l’exploitation de la durée des signaux de réveils. Notre solution se repose sur les caractéristiques matérielles du microcontrôleur (IRQ, Timer/Counter) des nœuds de capteurs. Elle permet de réduire les complexités liées aux conditionnements des signaux de réveils. Notre solution est implémentée sur un réseau de petite taille. Elle est évaluée expérimentalement et ses performances énergétiques sont comparées à celles d’un schéma classique de télé-réveil sans mécanisme d’adressage et à celles d’un schéma classique basé sur le duty-cycling. / Wireless sensor networks that are suitable for a wide range of applications, represent a promising solution that meets any requirement for continuous monitoring. The energy autonomy of sensor nodes constitutes a vulnerability factor that directly affects their longevity and the capacity of the network to ensure long coverage of the geographical area of interest. Energy consumption management is the only way to increase the lifespan of these networks and to give them a reasonable autonomy. Software solutions proposed through MAC protocols, bring significant improvements to the minimization of the energy expenditure of sensor nodes. They reduce the idle-listening periods which represents the most expensive operation in terms of energy, in the operation of the wireless sensor nodes. However, Focusing lonely on these solutions is not enough to guarantee acceptable longevity. The only way to optimize energy conservation in the WSN is to constantly put each node in low power mode and use a wakeup mechanism through wake-up signals. This involves the use of low-power wake-up circuits that provide channel monitoring, and trigger node wake-up only whenever event of interest occurs. In this context, a significant amount of work has proposed the use of an addressing mechanism (MAC addresses or other binary informations), to allow non-concerned nodes to quickly return to their sleep state. This approach is interesting, but involves a significant energy expenditure, related to address information’s reception and processing at all nodes. The most energy efficient solution would be the use of another type of address. This thesis is part of the context of minimizing the energy consumption of the WSN, using an addressing system that allows sensor nodes to receive and process the wake-up signals, without turning on their main communication module. It is to eliminate the energy expenditure related to the RF module’s activation and the reception of address packets, by exploiting wakeup signals duration. Our solution is based on the hardware characteristics of the microcontroller (IRQ, Timer/Counter) of sensor nodes. It reduces the complexities related to wakeup signals conditioning. Our solution is implemented on a small network. Its evaluations were done experimentally and its energy performance is compared to a conventional wake-up mechanism without addressing,and a conventional scheme based on duty-cycling.

The aim of this diploma theses is to find philosophical, religious and ideological motifs in the work of Ladislav Fuks and subsequently interpret their origin, intertextuality and meaning in the text. The emphasis is put on proving the semantic functionality in the story. For our research, we have selected following works: Mr. Theodore Mundstock, The Cremator, and Addressing from the Darkness. We will study philosophical and theological literature, as well as materials from the archives and from the estate of Ladislav Fuks in order to base all the findings on the biographical author, too. The thesis is divided into five chapters. In the first chapter we deal with basic literary characteristics of the selected books and their literary reception. The second chapter discusses Ladislav Fuks' relationship to philosophy, being anchored in both his friends' testimonies and the archival research of his estate. The third chapter is the most important and the most comprehensive one since it deals with the interpretation of philosophical motifs in each of the selected books. In the fourth chapter we compare individual philosophical motifs from different works with each other. We summarize the findings at the end of the theses.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This paper studied the organization of the teaching of sports content, with a view to the need for basic education students understanding it from a critical perspective. Part of the understanding that education in the capital´s landmarks is used as an effective means for restoration of capitalist hegemony, which implies the lowering of education for the lower classes, which most often seen in school the unique opportunity to access such knowledge. Consequently, there have taken students of basic education to a unilateral development, opposing the development of a degree of approximation to unilateral training. Therefore, we ask: how to organize the teaching of sports content in Physical Education - specifically athletics - based on complex system so that it can be grasped in its entirety and thus contribute towards developing a degree of approximation to unilateral training? Therefore, the objective is to analyze the possibility of complex system guide the appropriation of sport content in physical education classes in order to contribute to enhance aspects of human formation of the students. As for the results, there is the difficulty to organize sport education based on complex system, since the incompatibility that exists between the complex system and the educational culture of capitalist school prevents the broad development of this proposal. But despite the difficulties imposed by the objective conditions, it is considered that got it progress with regard to the degree of students´ understanding of the entire sport phenomenon, which confirms the hypothesis of the study, consolidating therefore the complex system as a chance to guide the deal with sports knowledge in order to contribute to a degree of approximation to unilateral training of students. / Este estudo tem como objeto a organização do ensino do conteúdo esporte, tendo em vista a necessidade dos alunos da educação básica apreendê-lo em uma perspectiva crítica. Parte da compreensão de que a educação nos marcos do capital é utilizada enquanto meio eficaz para recomposição da hegemonia capitalista, o que implica no rebaixamento do ensino destinado às camadas populares, que na maioria das vezes vê na escola a única oportunidade de acessar tais conhecimentos. Em consequência, têm-se levado os estudantes da educação básica a uma formação unilateral, em detrimento ao desenvolvimento de um grau de aproximação à formação onilateral. Diante disso, questiona-se: como organizar o ensino do conteúdo esporte nas aulas de Educação Física mais especificamente o atletismo com base no sistema de complexos a fim de que o mesmo possa ser apreendido em sua totalidade e, consequentemente, contribua na direção do desenvolvimento de um grau de aproximação à formação onilateral? Para tanto, o objetivo é analisar a possibilidade do sistema de complexos orientar a apropriação do conteúdo esporte nas aulas de educação física no sentido de contribuir para ampliar os aspectos da formação humana dos alunos. O estudo, de natureza quantitativa/qualitativa, foi realizado à luz do método materialista histórico-dialético, a partir da observação livre das aulas de educação física em uma turma de sétimo ano de uma escola pública do município de Arapiraca, Alagoas. Quanto aos resultados encontrados, destaca-se a dificuldade para organizar o ensino do esporte com base no sistema de complexos, posto que a incompatibilidade que existe entre o sistema de complexos e a cultura pedagógica da escola capitalista impede o amplo desenvolvimento desta proposta. Mas, apesar das dificuldades impostas pelas condições objetivas, considera-se que obtive-se um avanço no que se refere ao grau de compreensão dos alunos sobre a totalidade do fenômeno esportivo, o que confirma a hipótese do estudo, consolidando-se, portanto, o sistema de complexos enquanto uma possibilidade para orientar o trato com o conhecimento esporte na perspectiva de contribuir para um grau de aproximação à formação onilateral dos alunos.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / O uso de dispositivos multi-interface, tais como smart phones, tem crescido ao mesmo tempo que as demandas por melhores serviÃos de mobilidade em redes heterogÃneas. Neste cenÃrio, a ideia da continuidade de serviÃos tornou-se um requisito crucial. Para atender essas demandas, esquemas eficientes de handover devem ser desenvolvidos com o objetivo de alcanÃar o chamado Handover Transparente, que significa a mudanÃa de domÃnios de rede de uma forma transparente e sem a descontinuidade dos serviÃos para o usuÃrio final. Atualmente, existem diferentes esquemas de handover e alguns deles podem envolver diferentes tecnologias de acesso (Handover Vertical). Entretanto, o tempo de interrupÃÃo do serviÃo ainda à um problema a ser resolvido. A principal proposta deste trabalho à uma melhoria para Handovers Verticais utilizando mobilidade IP, objetivando o tÃo desejado Handover Transparente. Neste trabalho, fez-se uso do framework MIH (Media Independent Handover) fornecido pelo padrÃo IEEE 802.21 para habilitar o handover vertical em redes heterogÃneas. AlÃm disso, propÃe-se uma extensÃo do protocolo FMIPv6 (Fast Handovers for Mobile IPv6), o FaHMA (Fast Handovers using Multicast Addressing), utilizando endereÃamento multicast para gerenciar a mobilidade nesses tipos de rede. Para fazer a anÃlise de desempenho, simulaÃÃes foram utilizadas considerando-se mÃtricas tais com o atraso do handover e a perda de pacotes como os critÃrios mais importantes para avaliar a efetividade da soluÃÃo. Os resultados destas simulaÃÃes mostraram que o FaHMA obtÃm melhores resultados que o FMIPv6, inclusive em relaÃÃo aos fatores que determinam a qualidade do funcionamento de aplicaÃÃes multimÃdias em rede. / The use of multi-interface devices such as smart phones has grown at the same time as the demands for efficient mobility services in heterogeneous networks. In this scenario, the idea of service continuity has become a crucial requirement. To achieve these demands, efficient handover schemes should be developed aiming to achieve Seamless Handover, which means the change of network domains in a transparent way and without services discontinuity to the end user. Currently, there are different schemes for handover and some of them may be used between different access technologies (Vertical Handover). However, the service time disruption is still a major problem to be solved. The main purpose of this study is to propose an improvement for Vertical Handovers using IP mobility, aiming at Seamless Handover. In this work, the framework provided by the MIH (Media Independent Handover) IEEE 802.21 is used to enable vertical handover in heterogeneous networks, and propose an extension of FMIPv6 (Fast Handovers for Mobile IPv6) called FaHMA (Fast Handovers using Multicast Addressing), using multicast in order to manage mobility in these types of networks. To make the performance analysis, we decided for simulations and we considerered metrics such as the handover delay and packet loss as the most important criteria for evaluating the effectiveness of our proposal. Simulation results have shown that FaHMA achieve better results than FMIPv6, including factors that determine the quality of operation in networked multimedia applications.

This masters thesis describes simulation of network using Network Simulator. Model of network and description of simulation is extracted from the analysis of configuration files of active network devices, and translated by a parser. Concept and implementation of the parser is described here. Because IPv4 addressing is not supported in Network Simulator, it was added as a new module. The Network Simulator is also extended by filtering properties of packets using access control lists. Practical usage of the implemented modules is demonstrated on a simulation of real network.