Os Pontos de Troca de Tráfego participam de maneira substancial e crítica no ecossistema da Internet, possibilitando conexões entre múltiplos Sistemas Autônomos (ASes, do inglês Autonomous Systems). O gerenciamento das redes de PTT possui como objetivos primários, o gerenciamento dos chamados fluxos elefante (do inglês, elephant flows). Fluxos elefante tendem a existir em número reduzido, porém correspondem à maioria do tráfego em uma infraestrutura de rede. O gerenciamento dos fluxos elefante envolve uma adequada identificação e quando necessário, um redirecionamento destes fluxos para caminhos mais apropriados, de forma a minimizar os possíveis impactos sobre os outros fluxos ativos na rede. Além disso, o gerenciamento de fluxos elefante tornou-se um importante objeto de discussão em PTTs baseados em redes SDN, principalmente porque estas redes dispõem de controladores que possuem uma visão consistente da rede subjacente, o que permite uma gerência destes fluxos de forma refinada. Nesta dissertação, será proposto, desenvolvido e avaliado um sistema de identificação dos fluxos elefante e seus respectivos caminhos de rede, em conjunto com um sistema de recomendação, que possui o objetivo de sugerir configurações alternativas para os fluxos elefante identificados anteriormente nas redes de PTTs baseadas em SDN. Neste sistema, o operador do PTT pode definir templates que em última instância definem como os caminhos dos fluxos elefante serão modificados para atender objetivos específicos. Por fim, será demonstrado que o sistema proposto pode auxiliar o operador do PTT a identificar, gerenciar e mitigar o impacto dos fluxos elefante da rede do PTT. / Internet Exchange Points (IXPs) play a key role in the current Internet architecture enabling cost-effective connections among multiple autonomous systems (ASes). Management of IXP networks is primarily concerned with the management of the so-called elephant flows. Such flows represent a small portion of the total flows of a IXP network but usually have high impact on the overall traffic. Managing elephant flows involves adequate identification and eventually rerouting of such flows to more appropriate locations to minimize the possible negative impact on the other (mice) flows active in the network. Elephant flow management becomes more important in SDN-based IXPs that require controllers to have a consistent view of the underlying network to allow fine-grained adjustment. In this master thesis, we propose, develop, and evaluate an identification system to identify elephant flows and their respectively paths, as well as a recommendation system to suggest alternative configurations to previously identified elephant flows in an SDN-based IXP network. In this solution, the IXP operator can define templates that ultimately define how elephant flows can be reconfigured to achieve a specific objective. We demonstrate that our system can help IXP operators to identify, handle and mitigate the impact of elephant flows in the IXP network.

Em um futuro próximo, “dispositivos inteligentes” serão massivamente empregados em campos de batalha. Essa já é uma realidade, porém, o número de dispositivos utilizados em campos de batalha tende a aumentar em ordens de magnitude. As redes de comunicação de dados serão essenciais para transmitir os dados que esses dispositivos coletam e transformá-los em informações valiosas utilizadas como suporte à atuação humana. O suporte à tomada de decisão, ou mesmo níveis de autonomia, permitindo que estes dispositivos coordenem outros dispositivos, exigem comunicação contínua. Desafios relacionados à comunicação surgirão devido à dinamicidade do ambiente. A configuração da rede deve refletir decisões superiores automaticamente. A grande escala das redes conectando os altos escalões, tropas, veículos e sensores, aliada à falta de padronização dos dispositivos, tornará a integração destes desafiadora. Em um ambiente tão heterogêneo, muitos protocolos e tecnologias coexistirão. As redes de campo de batalha são um elemento de suma importância nas operações militares modernas e conceito de guerra centrada em rede é uma tendência sem volta e influencia desde os altos escalões até o controle de tropas Embora estudos tenham sido realizados nessa área, a maioria deles aborda redes estratégicas de alto nível e portanto não levam em conta as “redes táticas de última milha” (TEN), que compreendem dispositivos de comunicação com recursos limitados, como sensores ou ainda pequenos veículos aéreos não tripulados. Em uma tentativa de preencher esta lacuna, esse trabalho propõe uma arquitetura que combina conceitos dos paradigmas de redes definidas por software (SDN) juntamente com redes tolerantes à atraso/disrupçoes (DTN), para aplicação em redes táticas de última milha. O uso de SDN em cenários com nodos móveis é avaliado considerando uma aplicação de vigilância que utiliza streaming de vídeo e medidas de Qualidade de Experiência (QoE) de usuário são coletadas. Com base nos resultados obtidos, uma aplicação em conjunto dos conceitos de SDN e DTN é proposta, além disso abordamos a escolha do nodo que atuará como controlador SDN na rede. Os experimentos foram executados utilizando um emulador de redes. Apesar de pesquisas adicionais serem necessárias – considerado requisitos de segurança, por exemplo – os resultados foram promissores e demonstram a aplicabilidade destes conceitos no cenários das TENs. / The future battlefield tends to be populated by a plethora of “intelligent things”. In some ways, this is already a reality, but in future battlefields, the number of deployed things should be orders of magnitude higher. Networked communication is essential to take real advantage of the deployed devices on the battlefield, and to transform the data collected by them into information valuable for the human warfighters. Support for human decision making and even a level of autonomy, allowing devices to coordinate and interact with each other to execute their activities in a collaborative way require continuous communication. Challenges regarding communication will arise from the high dynamics of the environment. The network adaption and management should occur autonomously, and it should reflect upper-level decisions. The large scale of the network connecting high-level echelons, troops on the field, and sensors of many types, beside the lack of communication standards turn the integration of the devices more challenging. In such a heterogeneous environment, many protocols and communication technologies coexist. This way, battlefield networks is an element of paramount importance in modern military operations Additionally, a change of paradigm regarding levels of autonomy and cooperation between humans and machines is in course and the concept of network-centric warfare is a no way back trend. Although new studies have been carried out in this area, most of these concern higher-level strategic networks, with abundant resources. Thus, these studies fail to take into account the “last-mile Tactical Edge Network (TEN) level,” which comprises resource constrained communication devices carried by troopers, sensor nodes deployed on the field or small unmanned aerial vehicles. In an attempt to fill this gap, this work proposes an architecture combining concepts from software-defined networking (SDN) paradigm and the delay-tolerant approach to support applications in the last-mile TEN. First, the use of SDN in dynamic scenarios regarding node positioning is evaluated through a surveillance application using video streaming and Quality of Experience (QoE) measures are captured on the video player. We also explore the election of nodes to act as SDN Controllers in the TEN environment. The experiments use emulator for SDN with support to wireless networks. Further investigation is required, for example, considering security requirements, however the results are promising and demonstrate the applicability of this architecture in the TEN network scenario.

The aim of this master thesis is to create a web-based graphical user interface which communicates with a Software Defined Controller and the OpenFlow protocol to provide a basic network management and a topology graph, then to describe main aspects of the OpenFlow technology and to optimalize the chosen SDN Controller for full support in a multi-vendor enviroment.

The main purpose of this thesis work is to find and compare different network characteristics of MPS (Mobile Positioning System) in the different wireless technology domains. Since decades ago MNO’s (Mobile Network Operators) added many new services based on the geographical areas of subscribers and their needs. Here we define wireless networks and go through different types of technologies and do the comparison when they collect different types of data for their location-based services and see if we could have the same accuracy with 2G (second generation) of mobile network as like as 3G (third generation) and higher. Finally, we will come up with a proposal for new age technology.

The exploration of chemical space in search of molecules that perturb or mimic biological systems is essential to understanding human biology. The first part of this dissertation (Chapters 1-4) describes efforts to aid in the exploration of biologically relevant space through the invention of new π-cyclization methodologies. This strategy can be viewed as part of a “top-down” approach to investigating biology: the construction of small molecule drugs or probes which modify the behavior of the existing system. The second part of this dissertation (Chapter 5) describes preliminary efforts to expand life-like chemical space beyond the nucleic acids of DNA and RNA. This can be viewed as a “bottom-up” approach to biology: the construction of systems which mimic the features of biochemical processes. In part one, cyclizations of nitrogen tethered 1,6-diynes were developed as a means to new heterocyclic scaffolds. A GaX3 promoted halocyclization transformed the acyclic diynes into tetrahydropyridine rings with exocyclic vinyl halides. In the presence of strong acid, the tetrahydropyridine products were further cyclized to tetrahydroindenopyridine scaffolds. These scaffolds were then diversified through Pd(0)-catalyzed cross-coupling reactions of the vinyl halide, and modifications to the tethering amino nitrogen. Subsequently, a Brønsted acid-catalyzed cyclization was developed, transforming N-sufonyl tethered bis-aryl 1,6-diynes to dihydroindenopyridines. Using unsymmetric bis-aryl diynes, the regio- and chemoselectivity of this Brønsted acid-catalyzed cyclization was investigated, and compared to the GaX3 Lewis acid promoted cyclization developed previously. The regiochemical preference of the initial cyclization step was found to be reversed under the two different conditions. In part two, a means to sequence-defined synthetic polymers which emulate the information storage and self-replication abilities of nucleic acid-based biopolymers was designed. Information was encoded in two dimers as a specific sequence of aniline and benzaldehyde subunits, which were linked together by a diethynyl benzene backbone. These dimers functioned as a template for the synthesis of new dimers with a complementary sequence. Unpolymerized ethynylaniline and ethynylbenzaldehyde monomers, associated to a polymer template by reversible imine bonds, were polymerized via Sonogashira cross coupling with diiodobenzene. Under the same set of conditions, the sequence of two parent dimers was transferred to the daughters.

Cette étude s’inscrit dans une problématique d’économie d’énergie à travers l’augmentation des rendements des turbines à gaz. L’objectif est alors de mettre au point un procédé permettant la croissance et la mise en forme de céramiques d’oxydes à la composition eutectique pour l’élaboration d’aubes de turbine. En conservant leurs propriétés mécaniques jusqu’à 1700°C et en présentant une densité plus faible que les superalliages actuellement utilisés dans les aubes, ces nouveaux matériaux seraient une solution potentielle pour augmenter notablement le rendement global des turboréacteurs. Dans ce contexte, le procédé EFG utilisé pour la production de saphir a été identifié comme le procédé d’élaboration le plus prometteur, et la céramique Al2O3/YAG/ZrO2 comme la composition présentant les meilleurs propriétés mécaniques.Dans un premier temps une étude approfondie du procédé EFG utilisé par RSA le Rubis, l’entreprise dans laquelle s’est déroulé ce travail, a été menée. Nous avons alors réalisé un modèle analytique de résolution du point de fonctionnement du procédé. Ce modèle est basé sur nos connaissances dans la cristallisation de saphir et nécessite des ajustements pour convenir à la cristallisation de la céramique.Nous avons donc mesuré les propriétés de mouillage du matériau. La densité liquide et la tension de surface ont été mesurées à l’aide d’une méthode dérivée de la méthode de Wilhelmy. En outre, une simulation numérique du procédé, accompagnée de mesures de températures par thermocouple, a permis de connaitre plus précisément la distribution thermique à proximité de la zone de cristallisation. Cette étude complète les résultats du modèle.Ainsi, nous avons pu solidifier des plaques en céramique eutectique avec le procédé EFG. Plusieurs essais ont été nécessaires au dimensionnement d’une zone chaude assurant le maintien géométrique des plaques, puis de nombreux essais d’optimisation ont permis de prolonger les tirages et ainsi produire des plaques de plus grandes dimensions.Enfin, nous nous sommes intéressés à la caractérisation des céramiques. L’analyse des microstructures définit la vitesse de cristallisation maximale admissible pour réaliser des cristaux sans colonie, qui sont les défauts principaux dans ce type de microstructure. Une campagne d’essais mécaniques a également été effectuée, révélant des problématiques d’usinage nouvelles et particulièrement importantes. / This study is a part of an energy saving issues through an increase of gas turbine yields. The objective is to adapt a process for the growth of oxide ceramics with eutectic composition for the manufacture of turbine blades. Sustaining their mechanical properties up to 1700 ° C and with a lower density than superalloys which are currently used in the blades, these new materials are a potential solution to significantly increase the overall efficiency of jet engines. In this context, the EFG process used for the production of sapphire has been identified as the most promising process, and the eutectic composition Al2O3/YAG/ZrO2 as the ceramic with the best mechanical properties.First, a thorough study of the EFG process used by RSA le Ruby, the company where this work was conducted, was done. An analytic model to resolve the setting point of the process was realized. This model is based on the RSA le Rubis’s knowledge in the sapphire crystallization.The wetting properties of the material were measured to fit the model. The liquid density and surface tension were measured using a method derived from the Wilhelmy method. In addition, a numerical simulation of the process, accompanied by temperature measurement by thermocouple, was done. It allows to know the temperature distribution close to the crystallization zone with a better accuracy.Thus, eutectic ceramic plates were solidified with the EFG process. Several tests were necessary in order to design a process ensuring the solidification of net shaped plates. Then lot of optimization pulls have been done to extend the plate’s dimensions.Finally, some characterizations were achieved on the plates. Analysis of the microstructure defines the maximum rate of crystallization to produce crystals without colonies, which are the main defect in these kinds of microstructures. A campaign of mechanical testing was also performed, revealing new machining problems which are particularly important.

The research set out to explore the nature of challenges in distribution of old age pensions in Lesotho. Poor institutional capacity failed the implementing agency, the Department of Pensions; to set up competent administrative structures to run run the pensions effectively and efficiently. A number of challenges have been identified, some of which were: inadequate supervision of the paying officers, fraud by workers and community agents, missing funds, insufficient resources, inadequate administrative capacity, overworked employees, faulty targeting, soft and discriminatory approach to non-compliance with rules and multiple use of identity documents by recipients. On the other hand, a number of opportunities have been identified to counteract the challenges. The main recommendation of the study was the engagement of mobile phone-based money transfer facilities to transfer the old age pensions from the government to the recipients. The Department of Pensions should make use of baseline database like information from civil registration agency like the Ministry of Home Affairs to confirm the validity of the pension recipients. Other recommendations included moving the division of old age pensions from the Pensions Department to the Ministry of Social Development which is the controlling body for other forms of social grants in Lesotho. The Ministry of Social Development is regarded as well equipped with qualified staff and facilities to deal with vulnerable people like the elderly.

Energy conservation is a main concern in Wireless Sensor Networks (WSN). To reduce energy consumption it is important to know how it is spent and how much is available during the node and network operation. Several previous works have proposed energy consumption models focused on the communication module, while neglecting the processing and sensing activities. Other works presented more complex and complete models, but lacked experiments to demonstrate their accuracy in real deployments. The main objective of this work is to design and to evaluate an accurate energy consumption model for WSN, which considers the sensing, processing, and communication modules usage. This model was used to implement two energy consumption prediction mechanism. One mechanism is based in Markov chains and the other one is based in time series analysis. The metrics to evaluate the model and prediction mechanisms performance were: energy consumption estimation accuracy, energy consumption prediction accuracy, and node\'s communication and processing resources usage. The energy consumption prediction mechanisms performance was compared using two implementation schemes: running the prediction algorithm in the sensor node and running the prediction algorithm in a Software-Defined Networking controller. The implementation was conducted using IT-SDN, a Software-Defined Wireless Sensor Network framework. For the evaluation, simulation and emulation used COOJA, while testbed experiments used TelosB devices. Results showed that considering the sensing, processing, and communication energy consumption into the model, it is possible to obtain an accurate energy consumption estimation for Wireless Sensor Networks. Also, the use of a Software-Defined Networking controller for processing complex prediction algorithms can improve the prediction accuracy. / A conservação da energia é uma das principais preocupações nas Redes de Sensores Sem Fio (WSN, do inglês Wireless Sensor Networks). Para reduzir o consumo de energia, é importante saber como a energia é gasta e quanta energia há disponível durante o funcionamento da rede. Diversos trabalhos anteriores propuseram modelos de consumo de energia focados no módulo de comunicação, ignorando o consumo por tarefas de processamento e sensoriamento. Outros trabalhos apresentam modelos mais completos e complexos, mas carecem de experimentos que demonstrem a exatidão em dispositivos reais. O objetivo principal deste trabalho é projetar e avaliar um modelo de consumo de energia para WSN que considere o consumo por sensoriamento, processamento e comunicação. Este modelo foi utilizado para implementar dois mecanismos de previsão de consumo de energia, um deles baseado em cadeias de Markov e o outro baseado em séries temporais. As métricas para avaliar o desempenho do modelo e dos mecanismos de previsão de consumo de energia foram: exatidão da estimativa de consumo de energia, exatidão da previsão de consumo de energia e uso dos recursos de comunicação e processamento do nó. O desempenho dos mecanismos de previsão de consumo de energia foram comparados utilizando dois esquemas de implementação: rodando o algoritmo de previsão no nó sensor e rodando o algoritmo de previsão em um controlador de rede definida por software. A implementação foi conduzida utilizando IT-SDN, um arcabouço de desenvolvimento de redes de sensores sem fio definidas por software. A avaliação foi feita com simulações e emulações utilizando o simulador COOJA e ensaios com dispositivos reais utilizando o TelosB. Os resultados mostraram que considerando o consumo de energia por sensoriamento, processamento e communicação, é possivel fazer uma estimativa de consumo de energia em redes de sensores sem fio com uma boa exatidão. Ainda, o uso de um controlador de rede definida por software para processamento de algoritmos de previsão complexos pode aumentar a exatidão da previsão.

The objective of this thesis was to create a network emulator, suitable for evaluatingsolutions in a small-cell wireless mesh SDN backhaul network environment, by integratingexisting software. The most important efforts in this process have been a transparentintegration of Mininet and ns-3 at both the data and the control plane, with ns-3 servingas the front-end. The goal has been to design the system such that solutions revolvingaround fast failover, resilient routing, and energy efficient small cell management may beevaluated. The constituent components include an augmented ns-3 WiFi module withmillimeter wave communication capabilities; a socket API suitable for remote-controllermanagement, as well as the network emulator Mininet. Mininet in turn integrates OpenvSwitch, virtual hosts in the form of Linux network namespaces, and OpenFlow controllers.The work has also included a brief evaluation of the system, which revealed that the designhas a fundamental flaw. / SOCRA

Esta dissertação trata das características próprias dos problemas de projeto de desenvolvimento de produtos. Os objetivos deste trabalho foram revisar parte da literatura publicada sobre a natureza dos problemas de projeto; confirmar, na prática, a mudança na definição dos componentes do problema ao longo da sua resolução; e propor uma estrutura que auxilie a escolha de ferramentas de geração de alternativas. São apresentados os resultados de uma observação do processo projetual realizado por estudantes de graduação da Engenharia e do Design, trabalhando conjuntamente. A dissertação é estruturada na forma de três artigos encadeados. Os resultados da revisão bibliográfica conformam o primeiro artigo, referente ao capítulo dois deste documento. A observação dos grupos de estudantes está no segundo artigo, referente ao capítulo três. A contribuição busca facilitar a tradução dos requisitos de um projeto em conceitos de um produto, através da proposição de uma matriz que cruza as dimensões dos problemas de projeto de produtos manufaturados industrialmente e algumas ferramentas conhecidas para a geração de alternativas. Essa matriz se encontra no terceiro artigo, referente ao capítulo quatro do documento. No quinto e último capítulo são elaboradas as conclusões do estudo, que apontam para a recursividade da atividade de definir um problema paralelamente ao seu processo de resolução. / This study is about the nature of design problems. Its objectives are: to review part of the literature about the topic; to confirm, with empirical basis, the changes in the components of design problem through the resolution process; and present a framework that helps choosing concept generating tools. The empirical data were obtained from observation and verbal protocols of graduation students from Engineering and Design courses working together. This research is presented in three linked articles, setting chapters two, three and four of this document. Chapter two represents the literature review. The observation of the students corresponds to chapter three. The contribution appears in chapter four, where the design problem dimensions are crossed with tools for concept generation. Lastly, in the fifth chapter, the conclusions pointed out to the recursiveness in the problem definition and solution generation process.