Dans le contexte des Réseaux Optiques Passifs (PON), les opérateurs recherchent des solutions innovantes pour augmenter le débit agrégé, nombre d'utilisateurs et portée de la transmission. En plus, des solutions émetteurs-récepteurs à bas coût sont nécessaires. La technique de transmission Orthogonal Frequency Division Multiplexing (OFDM) peut améliorer les performances de la communication en termes de débit agrégé et portée comparé à la modulation classique On-Off Keying (OOK) mono-porteuse. Au même temps, la technologie Photonique sur Silicium permet de réduire le coût par unité des émetteurs-récepteurs, en raison de sa capacité de production en masse et intégration électro-optique. L'OFDM optique a déjà démontré son potentiel avec des composants optiques sur étagère. Par contre, son utilisation avec des émetteurs compatibles avec la technologie Photonique sur Silicium est plus difficile. L'objectif de ce travail est d'étudier les performances d'un lien basé sur des composants Photoniques sur Silicium utilisant la technique de modulation OFDM. Pour atteindre cet objectif, une plateforme de simulation dédiée est développée. Le modulateur-démodulateur OFDM est mise en place, ainsi que des modèles d'émetteurs Photoniques sur Silicium développés pendant la thèse. Ces modèles sont validés expérimentalement avec la caractérisation des composants disponibles au laboratoire. En parallèle, un banc expérimental est construit. Les émetteurs Photoniques sur Silicium sont comparés avec des composants à l'état-de-l' art sur étagère dans un lien OFDM optique. Dans les systèmes en modulation d'intensité et détection directe (IM/DD), une technique d'allocation quasi-optimale de bits et puissance avec de l'OFDM optique est proposée pour maximiser l'efficacité spectrale. Deux types d'émetteurs Photoniques sur Silicium sont considérés : des lasers hybrides III/V-sur-Silicium en modulation directe (expérimentation) et des modulateurs externes comme le Mach-Zehnder (MZM) (simulation) et en anneau-résonant (expérimentation et simulation). Les résultats expérimentaux montrent qu'un débit agrégé de 10Gbps peut être attendu jusqu'à 50km de fibre monomode, compatible avec les exigences de futures générations de PONs. La portée de la transmission (>10Gbps) avec le modulateur en anneau est limitée à 20km, en raison des pertes de couplage élevé en entrée/sortie de la puce. Les simulations montrent que la portée peut atteindre 100km si les pertes sont réduites. Une technique de modulation appelée Single-Side Band (SSB)-OFDM est connu pour améliorer le produit bande-passante-portée de la transmission, en comparaison avec des systèmes IM/DD (Dual-Side Band (DSB)). Par contre, l'émetteur SSB exige plusieurs composants électriques et optiques discrets, augmentant sa complexité. La technologie Photonique sur Silicium permet de un haut niveau d'intégration électro-optique. Pour cette raison, une implémentation spécifique d'un modulateur optique IQ sur Silicium permettant une génération efficace d'un signal SSB-OFDM est étudiée. Les résultats de simulation d'un cas d'étude montrent que l'émetteur Silicium permet d'atteindre une pénalité dans le budget optique relativement faible (de l'ordre de 3dB) comparé à un modulateur LiNbO3. Les solutions présentées dans cette thèse répondent aux besoins de future générations de PON en termes de débit avec des bandes-passantes relativement faibles (<6.25GHz). Ceci est un atout pour l'application considérée. Les tensions de modulations pour les liens IM/DD sont proches des celles fournies par l'électronique CMOS (about 2Vpp). Le développement récent de processeurs numériques et de convertisseurs numériques-analogiques à haut débit en CMOS font de l'OFDM une solution très attractive pour les futures générations de PONs, puisque des transmetteurs tout-Silicium peuvent désormais être envisagés. / In the context of Passive Optical Networks (PON), operators are looking for innovative solutions to increase aggregated data-rate, split-ratio and reach. Another requirement is that transceivers should be as low-cost as possible. The optical Orthogonal Frequency Division Multiplexing (OFDM) technique can improve performance of the transmission in terms of data-rate and reach as compared to classical single-carrier On-Off Keying (OOK) modulation. At the same time, the silicon photonics technology can lower the cost per unit of the transceiver, due to its mass production and E/O integration capabilities. Optical OFDM has already shown its potential using commercially available optical components. However, its use with silicon photonics Directly-Modulated Lasers (DML) and modulators is more challenging. The objective of this work is to study the performance of OFDM -based solutions for future PON, using silicon photonics transmitters. For that purpose, a dedicated simulation platform is developed. The OFDM modem is implemented, as well as models of silicon photonic devices built during this thesis. These models are validated by characterizing physical components available for test. In parallel, an experimental test-bed is developed. The silicon photonics transmitters are benchmarked with commercial-available transmitters for OFDM-based optical systems. For Intensity-Modulated/Directly-Detected (IM/DD) links, the use of optical OFDM with adaptive bit and power loading is proposed to maximize spectral efficiency. Two types of silicon photonics transmitters are considered: directly modulated III/V-on-silicon lasers (experiment) and external optical modulators such as Mach-Zehnder Modulator (MZM) (simulation) and ring-resonator (simulation and experiment). Experimental results show that the hybrid DML can provide more than 10Gbps aggregated data-rate over at least 50km, which is a requirement for future uplink PON (from the subscriber to the central office). For the silicon ring modulator, because of the high coupling loss in and out of the photonic chip, reach was limited to 20km for a data-rate higher than 10Gbps. These are the first experimental demonstrations of OFDM modulation with hybrid III/V-on-silicon lasers and silicon ring-resonator modulator. Besides, simulation results show that reach can be indeed improved up to 100km if the optical signal is amplified or the coupling loss reduced. A modulation technique called Single-Side Band (SSB)-OFDM is known to improve the [bandwidth x reach] product of the link, as compared to IM/DD (Dual-Side Band (DSB)) systems. However, it requires expensive transmitters with several discrete optical components. As silicon photonics technology allows a very high level of integration between different optical components and between electrical and optical devices, a silicon optical IQ modulator enabling ac{SSB}-ac{OFDM} technique is investigated. Simulation results of a study-case reveal that a relatively low optical budget penalty (up to 3dB) of the silicon photonics transmitters as compared to the LiNbO3 modulator is achieved. The solutions presented in this thesis are demonstrated to be compliant with future PON in terms of data-rate, with relatively low bandwidth (<6.25GHz) electronics. This is a great asset for the considered application. The driving voltages required for typical IM/DD systems showed to be closer to what CMOS driving circuitry can provide (about 2Vpp). Recent developments on high-speed digital signal processors and D/A-A/D converters, using CMOS technologies, make optical-OFDM an attractive solution for future PONs as full-Silicon-transmitters could be used.

Orientador: Eleri Cardozo / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-16T06:51:09Z (GMT). No. of bitstreams: 1 Badan_TomasAntonioCosta_D.pdf: 1510212 bytes, checksum: 73618c2b1cfc1df892bb1bd071694ef9 (MD5) Previous issue date: 2010 / Resumo: A próxima geração da telefonia celular, 4G, será totalmente baseada no protocolo IP. Para o usuário final, a expectativa é estar constantemente conectado à esta rede, no qual a característica fundamental será a mobilidade transparente do dispositivo móvel, entre as várias subredes que compõem um domínio administrativo. Esta tese tem por objetivo propor uma solução para o problema da mobilidade transparente do dispositivo móvel em redes IP. Como consequência, duas contribuições são alcançadas. A primeira é a especificação de uma arquitetura que permita localizar e rastrear o dispositivo móvel em um domínio administrativo, que seja independente da tecnologia de túneis utilizada na camada de rede. A segunda é a proposição de um método de rastreamento do dispositivo móvel em redes MPLS, preservando as especificações do protocolo MPLS. É mostrado também como este método foi integrado com a arquitetura previamente definida. Por fim, é descrita como essa proposta de rastreamento em redes MPLS foi implementada sobre o sistema operacional Linux e os testes realizados para avaliar, tanto a implementação desta proposta, quanto a sua integração com essa arquitetura / Abstract: The next generation of cellular telephony, 4G, is going to be totally based on the IP protocol. The end user expects to be constantly connected to this network, in which the key feature Will be the seamless mobility of the mobile device among the various subnets within an administrative domain. This thesis has as objective to propose a solution to the problem of seamless mobility of the mobile device in IP networks. As such, two contributions are achieved. The first one is the specification of an architecture able to locate and track the mobile device inside an administrative domain, being independent of the tunnel technology used in the network layer. The second one is the proposition of a method to track the mobile device inside a MPLS networks, keeping intact the specifications of the MPLS protocol. It is also shown how this method was integrated with the previously defined architecture. Finally, it is described how the proposed method to track mobile devices inside a MPLS network was implemented on the Linux operating system, and the tests performed in order to assess both the implementation of this proposal and its integration with this architecture / Doutorado / Engenharia de Computação / Doutor em Engenharia Elétrica

Orientadores: Michel Daoud Yacoub, Ugo Silva Dias / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-20T07:39:19Z (GMT). No. of bitstreams: 1 Krishnan_Aravind_M.pdf: 14799172 bytes, checksum: ef1f7ee0181d66e5163ba0926643ca9e (MD5) Previous issue date: 2011 / Resumo: Esta tese apresenta os resultados de medidas de campo conduzidas na freqüência de 5.5 GHz, com o objetivo de caracterizar os parâmetros do modelo de desvanecimento alpha-mu. Mais especificamente, uma quantidade de situações é investigada para se determinar a densidade de probabilidade e a função de autocorrelação destes parâmetros. O range de valores possíveis são então sugeridos baseado nos dados empíricos. Adicionalmente, as variações instantâneas da magnitude dos parâmetros correspondentes são mostradas em função do deslocamento do receptor ao longo do percurso. Os resultados provêem informações importantes sobre a utilidade prática do modelo alpha-mu mostrando, em seguida, que as estatísticas do sinal recebido se distanciam bem daquelas dos modelos conhecidos / Abstract: This thesis presents the results of field trial measurements conducted at a frequency of 5.5 GHz in order to characterize the parameters of the !-? fading model. More specifically, a number of situations are investigated in which the probability density function and the autocorrelation function of these fading parameters are described. The ranges of possible practical values of the parameters are then suggested as an outcome of the empirical data. In addition, the instantaneous magnitude variations of corresponding parameters are shown as a function of the receiver position along the path. The results provide important information about the practical usefulness of the !-? fading model, showing, in addition, that the received signal statistics greatly departs from the well known statistical models / Mestrado / Telecomunicações e Telemática / Mestre em Engenharia Elétrica

The modern smart grid would involve deep integration between measurement nodes, communication systems, artificial intelligence, power electronics and distributed resources. On one hand, this type of integration can dramatically improve the grid performance and efficiency, but on the other, it can also introduce new types of vulnerabilities to the grid. To obtain the best performance, while minimizing the risk of vulnerabilities, the physical power system must be designed as a security aware system. In this dissertation, an interoperability and communication framework for microgrid control and Cyber Physical system enhancements is designed and implemented taking into account cyber and physical security aspects. The proposed data-centric interoperability layer provides a common data bus and a resilient control network for seamless integration of distributed energy resources. In addition, a synchronized measurement network and advanced metering infrastructure were developed to provide real-time monitoring for active distribution networks. A hybrid hardware/software testbed environment was developed to represent the smart grid as a cyber-physical system through hardware and software in the loop simulation methods. In addition it provides a flexible interface for remote integration and experimentation of attack scenarios. The work in this dissertation utilizes communication technologies to enhance the performance of the DC microgrids and distribution networks by extending the application of the GPS synchronization to the DC Networks. GPS synchronization allows the operation of distributed DC-DC converters as an interleaved converters system. Along with the GPS synchronization, carrier extraction synchronization technique was developed to improve the system’s security and reliability in the case of GPS signal spoofing or jamming. To improve the integration of the microgrid with the utility system, new synchronization and islanding detection algorithms were developed. The developed algorithms overcome the problem of SCADA and PMU based islanding detection methods such as communication failure and frequency stability. In addition, a real-time energy management system with online optimization was developed to manage the energy resources within the microgrid. The security and privacy were also addressed in both the cyber and physical levels. For the physical design, two techniques were developed to address the physical privacy issues by changing the current and electromagnetic signature. For the cyber level, a security mechanism for IEC 61850 GOOSE messages was developed to address the security shortcomings in the standard.

As high-speed networks with large bandwidth delay products (BDP) become more common, high-speed transport protocols must be developed that perform well in these contexts. TCP has limitations in high BDP networks. A number of high-speed TCP proposals have emerged, including BIC TCP, High Speed TCP, and H-TCP. XCP is an intraprotocol communication mechanism that promises even greater performance by providing explicit feedback from routers about congestion. It requires changes to routers and end hosts, though, whereas the other experimental protocols only require changes to an end host. We evaluated the performance ofXCP against BIC TCP, High Speed TCP, H-TCP, and . NewReno TCP. We found that in a controlled environment, XCP gave much better performance than the other TCPs. XCP was sensitive to misconfiguration and environmental factors, though, and was more difficult to deploy. More work is required to make XCP more stable. The other TCPs did not perform better than NewReno TCP but show promise, as most performed almost as well as NewReno TCP.

Orientador: Reginaldo Palazzo Júnior / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-18T16:43:26Z (GMT). No. of bitstreams: 1 Pilla_ElianeCristinaGeroli_M.pdf: 2007393 bytes, checksum: 2b95255e6d4fca123c23a039d1a083a5 (MD5) Previous issue date: 2005 / Resumo: O presente trabalho tem como meta principal construir constelações de sinais geometricamente uniformes no plano hiperbólico, visando considerá-las como alfabeto para geração de códigos de espaço de sinais, em particular os códigos de classes laterais generalizados. Para estabelecer estas constelações foi escolhido um conjunto de sinais geometricamente uniforme, constituído pelos centros dos octógonos da tesselação {8, 8}. Depois foi obtido um rotulamento para os elementos do grupo gerador dos conjuntos de sinais geometricamente uniformes em cada classe lateral. Finalmente, a partir do isomorfismo rótulo obtivemos um rotulamento isométrico para os elementos do conjunto de sinais / Abstract: Our goal in this work is to construct hyperbolic geometrically uniform signal constellations (more specifically g-torus) that are able to act as alphabets for ge neration of codes. To obtain these constellations we choose geometrically uniform signal sets consisting of the centers of the p-gons of tessellations of type {p, q}. From these constellations we obtain labelings for the elements of the generator group of the geometrically uniform signal sets in each coset. Finally, by the label isomorphism we obtain an isometric labeling for the elements of the signal set / Mestrado / Telecomunicações e Telemática / Mestre em Engenharia Elétrica

In recent years, there has been an enormous growth of location-aware devices, such as GPS embedded cell phones, mobile sensors and radio-frequency identification tags. The age of combining sensing, processing and communication in one device, gives rise to a vast number of applications leading to endless possibilities and a realization of mobile Wireless Sensor Network (mWSN) applications. As computing, sensing and communication become more ubiquitous, trajectory privacy becomes a critical piece of information and an important factor for commercial success. While on the move, sensor nodes continuously transmit data streams of sensed values and spatiotemporal information, known as ``trajectory information". If adversaries can intercept this information, they can monitor the trajectory path and capture the location of the source node. This research stems from the recognition that the wide applicability of mWSNs will remain elusive unless a trajectory privacy preservation mechanism is developed. The outcome seeks to lay a firm foundation in the field of trajectory privacy preservation in mWSNs against external and internal trajectory privacy attacks. First, to prevent external attacks, we particularly investigated a context-based trajectory privacy-aware routing protocol to prevent the eavesdropping attack. Traditional shortest-path oriented routing algorithms give adversaries the possibility to locate the target node in a certain area. We designed the novel privacy-aware routing phase and utilized the trajectory dissimilarity between mobile nodes to mislead adversaries about the location where the message started its journey. Second, to detect internal attacks, we developed a software-based attestation solution to detect compromised nodes. We created the dynamic attestation node chain among neighboring nodes to examine the memory checksum of suspicious nodes. The computation time for memory traversal had been improved compared to the previous work. Finally, we revisited the trust issue in trajectory privacy preservation mechanism designs. We used Bayesian game theory to model and analyze cooperative, selfish and malicious nodes' behaviors in trajectory privacy preservation activities.

Discusses the development of WebSAT (Web-based systems administration tool), a computer network tool that allows systems administrators to create and delete accounts, disable and enable existing accounts, manage disk space conveniently, monitor the status of all network printers, and monitor network security. The WebSAT application was implemented using PHP, a server-side embedded scripting language, with a MySQL database.

This project occupies with the creation modulated signal generator in MATLAB. There are explicit basic princips of modulation PSK, M-QAM, princip of system with spread spektrum and princip of access OFDM and MC-CDMA. Next there are explicit basic parametres and possibilities configuration of conversion analog PCI card CompuGen 4302, which serves as D/A convertor of signals created by PC.

L'accompagnement en tant qu'auxiliaire de vie scolaire de Max, adolescent diagnostiqué autiste Asperger, fut le cadre de notre observation et de recherche clinique. Max a l'habitude d'aller toucher les cheveux d'autrui, ce que nous envisageons comme la manipulation d'un objet autistique atypique et une modalité particulière de rencontre de l'autre. À partir des travaux et des références de Francès Tustin, nous proposons une recherche à propos des fondements métapsychologiques de la notion d'objet autistique afin de déterminer quels sont les processus psychiques qui sous-tendent leur apparition. Nous étudions les cheveux en tant qu'éléments corporels symboliques et découvrons leur polysémie. Puis nous comparons la fonction et la manipulation des objets autistiques à celles des objets transitionnels, fétiches et self-objects, ce qui nous permet de penser des modalités spécifiques de relations d'objet. Notre hypothèse de la relation autistique à l'objet envisage l'émergence des objets autistiques en tant que témoins d'une relation à l'autre impossible et évitée, mais néanmoins recherchée et désirée. Cet évitement mènerait à l'intérêt pour un objet matériel. En outre, nous présentons le travail d'élaboration de notre accompagnement et de notre relation. Ainsi, l'élaboration du contre-transfert s'étaye sur une mise en dialogue de la situation d'observation et d'œuvres littéraires. Enfin, nous proposons une extension de la notion d'objet autistique et de la relation autistique à l'objet par une réflexion sur les nouvelles modalités de relation à l'autre que constituent les communications numériques. / The help I provided to Max as a school assistant was our context for the clinical research presented in this thesis. Max is a handicapped teenager diagnosed with Asperger's syndrome. He is used to touch other people's hair, which we consider as an atypical autistic object and a particular mode of meeting others. Based on Francès Tustin's work and research, we offer a study about the metapsychological foundations of the autistic object's concept to define the psychic processes underlying their appearance. We consider hair as a symbolic part of the body and found their polysemy. Then we compare the autistic object's fonction and manipulation with those of transitionnal objects, fetish objects and self-objects, which allows us to think of specific modes of object relations. Our hypothesis about autistic object relations considers the emergence of autistic objects as witnesses of an impossible and avoided relation to another, nevertheless sought and desired. This avoidance would lead to the interest for a material object. Moreover, we present the development of our study, in helping and relationship. Therefore the countertransference elaboration is based on dialogue between our observation situation and literary work. At last, we propose an extension of the autistic object concept and of the autistic object relation by reflecting on the new forms of communication with others, like digital communications.