Made available in DSpace on 2014-06-11T19:24:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-02-26Bitstream added on 2014-06-13T19:51:45Z : No. of bitstreams: 1 nerisjunior_cp_me_arafcl.pdf: 994070 bytes, checksum: 1e7f6bed072b124d156371007b2d3995 (MD5) / As transformações tecnológicas no campo das tecnologias de informação e comunicação (TICs) têm mudado a dinâmica da economia mundial nos últimos anos. Este campo tem sido fonte de inovação e aumento da produtividade para todos os setores da economia, ao passo que tem vivenciado mudanças no interior das indústrias relacionadas. Tais mudanças podem ser percebidas através de três fenômenos imbricados: (i) as transformações técnicas e produtivas do setor de telecomunicações nos últimos vinte anos; (ii) as mudanças recorrentes na estrutura de mercado da indústria e nas competências tecnológicas requeridas do setor de telefonia e; (iii) a emergência de atores relevantes no conhecimento técnico-científico de países emergentes no setor. Procuramos descrever estes fenômenos nesta dissertação e suas implicações nas economias nacionais e mundial, bem como procuramos identificar as restrições e oportunidades engendradas por elas para o Brasil. Isto foi feito através (i) da análise das mudanças técnicas-produtivas do setor de telecomunicações, bem como a emergência de novas tecnologias e os processos co-evolutivos entre os atores relacionados; (ii) da análise do setor de telefonia móvel em termos de estrutura de mercado, as competências tecnológicas requeridas e o acúmulo de capacitações das empresas do setor; e (iii) da identificação da estratégia de catching up do setor de telecomunicações chinês, cujas empresas têm adquirido notável importância mundial na nova conformação do setor, e sua correlação com a infra-estrutura tecnológica do país, procurando tirar lições para o Brasil / The technological transformations undertaken by information and communication technologies (ICTs) have changed the dynamics of the world economy in recent years. It has been a source of innovation and productivity growth for all sectors of the economy, while it has experienced changes within the related industries. Such changes can be perceived through three technologically intertwined phenomena (i) the technical transformation in the telecommunications industry in the last twenty years, (ii) the recurrent changes in market structure of the industry and technological capabilities in the industry of mobile communications; and (iii) the emergence of relevant actors in the technical and scientific knowledge of emerging economies. We have described these phenomena in this dissertation as well as their implications for national and world economies, and tried to identify their constraints and opportunities for Brazil. This was done by (i) analysing technical-productive change in the telecommunications industry, as well as the emergence of new technologies and their co-evolutionary processes between actors, (ii) analysing the mobile phone industry in terms of market structure and technological skills required and the accumulation of skills by the sector companies, and (iii) identifying the catching up strategy of the Chinese telecommunications industry, whose enterprises have gained considerable importance in the new global configuration of the sector, and its correlation with the Chinese technological infrastructure, seeking to draw lessons for Brazil

Le secteur des télécommunications est devenu très important pour notre société, car, non seulement permet-il de mettre en relation des personnes se trouvant à des bouts opposés dans le monde, mais il contribue également à la croissance de notre productivité. Afin de bénéficier au maximum de ce secteur, il est indispensable de bien comprendre son fonctionnement. Le but de cette thèse est justement de contribuer à sa meilleure compréhension. Elle vise en particulier des questions relatives à son environnement concurrentiel. Un premier volet se concentre sur la concurrence entre les services de télécommunication : les services fixes et mobiles. En effet, des évolutions contradictoires sont observées depuis quelque temps. D'abord, le nombre de consommateurs qui n'utilisent que leur mobile pour satisfaire leurs besoins en télécommunications ne cesse d'augmenter. Ensuite, le nombre de souscription d'offres groupées, regroupant des services fixes et mobiles, connaît également une hausse importante. Se pose alors la question, traitée dans le premier chapitre, concernant la rentabilité de cette pratique pour les opérateurs de télécommunications, ainsi que l'impact sur le bien-être social lié à cette stratégie. Un modèle théorique, intégrant à la fois la différenciation horizontale, la substitution fixe-mobile et les préférences hétérogènes des consommateurs, permet de conclure que les opérateurs risquent de subir des pertes de profits, alors que les consommateurs profitent de cette pratique. Par ailleurs, le gain des consommateurs est plus grand que la réduction de profits des opérateurs, de façon à ce que le welfare social augmente. La substitution fixe-mobile est également au cœur du deuxième chapitre qui cherche à déterminer les caractéristiques socio-démographiques d'environ 20.000 utilisateurs français expliquant le mieux leur choix en matière de souscription soit à une offre mobile en tant que service unique, soit à une offre groupée ou encore à plusieurs services séparément. Le résultat principal est que les utilisateurs «mobile-only» semblent avoir une contrainte de budget plus serrée que les utilisateurs «multi-services». Par ailleurs, l'étude fait apparaître un avantage pour l'opérateur historique quand il s'agit de souscrire une offre groupée.Le deuxième volet de cette thèse traite de la concurrence entre entreprises. En particulier, le troisième chapitre propose d'analyser l'impact de l'interaction entre la réglementation sectorielle (notamment la régulation de prix) et le droit de la concurrence (notamment, l'interdiction de la pratique dite de «ciseau tarifaire») sur l'équilibre dans une industrie de réseau. Le débat sur ce sujet a engendré des points de vue diamétralement opposés, spécialement entre les USA et l'Europe : alors que ces deux outils sont considérés comme substituts outre-Atlantique, ils sont des compléments dans la conception européenne. La question est donc évidente: laquelle de ces deux doctrines a le moins d'impact sur l'efficacité du marché ? Une analyse théorique permet de montrer que le prix de détail pratiqué par une firme verticalement intégrée, propriétaire du réseau physique et qui, contre paiement d'une «charge d'accès», laisse son concurrent accéder à son réseau, peut ne pas respecter le droit de la concurrence sans qu'il y ait une intention anticoncurrentielle. Par ailleurs, l'application du droit de la concurrence en combinaison avec la réglementation des prix (notamment, la charge d'accès) mène à une inefficacité du marché représentée par une hausse des prix de détails, néfaste non-seulement pour le consommateur, mais aussi pour le welfare social. Cette thèse conclut en rappelant l'importance d'une compréhension approfondie du fonctionnement du secteur des télécommunications. Parce que les évolutions reconnues dans ce secteur ne sont pas anodines, des analyses théoriques et empiriques sont nécessaires afin que chacun puisse bénéficier des apports de ce secteur. / The telecommunications sector has becomes very important for today's society, as it allows people at either end of the world to communicate, as well as it contributes to the growth of our productivity. In order to fully benefit from this sector, a deep understanding of its functioning is indispensable.The aim of this thesis is to contribute to its better comprehension by focusing in particular on questions relative to the competition in this sector.This thesis concentrates first on the competition between fixed and mobile telecommunications services. Indeed, contradictory evolutions are observed. First, the number of consumers relying only on their mobile so as to satisfy their need in telecommunications increases steadily. Second, the number of subscriptions of bundled offers, regrouping fixed and mobile services, has also increased in an impressive manner. The question, treated in the first chapter, is thus to know whether the practice of bundling is profitable for telecommunications operators, as well as the impacts on social welfare induced by this strategy.A theoretical model, integrating horizontal differentiation, Fixed-Mobile substitution and heterogeneous consumer preferences, allows to conclude that operators are likely to lose profits when bundling their services, whereas consumers are clear winners. Furthermore, the increase of consumer surplus more than compensates the firms' profit losses, such that social welfare increases.Fixed-Mobile substitution is also at the core of the second chapter. Its aim is to determine the socio-demographic characteristics of about 20.000 French users that explain best the users' choice of subscribing either to only a mobile offer, to a bundled offer or to several services separately.The main result is that “mobile-only” consumers seem to have a stronger budget constraint than “multi-service” users. Moreover, the study provides evidence for an “incumbency advantage” when it comes to subscribing to a bundled offer.The thesis then turns to competition between firms. More specifically, the third and last chapter offers an analysis of the impact on the equilibrium in a network industry induced by the interaction of sector regulation (notably, price regulation) and competition law (notably, the prohibition of the so-called “margin squeeze”). The debate on this subject has induced two widely opposed points of view, in particular between the US and Europe: whereas the US considers both tools to be substitutes, they are used as complements in Europe. The underlying question is thus evident: which doctrine has the least impact on the market efficiency?A theoretical analysis allows first to show that the retail price set by a vertically integrated firm, that owns the physical network and grants its downstream competitor access to it against the payment of an “access charge”, may not comply with competition law without any anticompetitive intention. Moreover, applying competition law in combination with sector regulation (notably, regulation the level of the access charge) leads to market inefficiency, characterized by an increase of retail prices, which is detrimental to consumer surplus and social welfare.The thesis concludes by reminding the importance of a deep understanding of the functioning of the telecommunications sector. Since the evolutions in this sector are not harmless, many theoretical and empirical analyses are need, so that every one can profit from the contribution of this sector.

These thesis report deals with a range of secure high-speed networking over a metropolitan or wide area. Since this is quite active research area, a full report is given of the interfaces that thrive in removing the bandwidth burden from long distance networks. Only those with the status or potential of a standard are taking into consideration. Next, the position of security is evaluated. It is recommended that the access Interface enjoys certain advantages over the upper layers. Hence, the results of this work are directly applicable to virtually any layered communication architecture. Amongst the security protocols that are available, the IEEE802.11 represents the only viable solution to have the CLS service properly secured. This protocol is designed for a different type of environment and the implications of this are known. In the real sense, IEEE802.11 proves to be a very valuable tool to built multi-level secure private and public networks using the most recent MAN/WAN technologies. Furthermore, it shows how to enhance the security issues related to Metropolitan and Wide Area Network considering the required security services and mechanism.

Today, an increasing amount of the functionality traditionally associated with stationary computers is moving into mobile devices. Furthermore, the number of applications that retrieve data via networks is increasing in view of the recent growth of video streaming to the browsers, further emphasizing the Quality of Experience (QoE) requirements of mobile users today. Obviously, QoE demands are not necessarily connected to the fact that the link is mobile, which puts significant QoS demands onto the mobile systems involved. Consequently, this requires mobile systems to be flexible and adaptable to meet the QoS demands and cope with dynamic operating environments. Additionally, the rapid migration towards wireless connectivity and the abundance of mobile devices has put even greater strain on current wireless access technology designs. The frequency spectrum is a limited resource and must be efficiently utilized to conserve capacity and avoid overcrowding, particularly in densely populated areas. Hence, new wireless technologies and innovative architectural designs are needed to manage and to govern the wireless domain. The thesis is about combining the potential of Dynamic Spectrum Access (DSA) provided by Cognitive Radio (CR) with the scalability and fault tolerance capabilities demonstrated by Peer-to-Peer (P2P) systems. By combining these two technologies, we show that we can improve the resource utilization in crowded metropolitan areas to ensure service continuation between local mobile devices with minimal infrastructure requirements. The aim is to optimize the communication between Cognitive Radio Devices (CRD) in a Cognitive Radio Network (CRN) according to end-to-end (e2e) goals and user preferences.

There is no doubt that security mechanisms, such as authentication, are required in Information and Communication Technology, but they come at a price: Users need to spend additional time and effort to authenticate themselves. With this in mind, user perception of authentication is an important factor for successful use of authentication solutions. If users perceive an authentication procedure as time-consuming and difficult, they might ignore or try to bypass it. Therefore, user-perceived Quality of Experience (QoE) should be investigated. QoE is a challenging area as it, in this case, covers network performance and security as well as Human Computer Interaction and user experience. Throughout this work, authentication performance is investigated, starting with a framework for evaluating security architectures and authentication solutions in general. Criteria for user-friendliness, security and simplicity are described and the evaluation methods span from theoretical to practical, and qualitative to quantitative methods. The latter two aspects are investigated by a study of user experience of web authentication with OpenID using the EAP-SIM authentication method. The user experiments resulted in several user models of QoE. One particular user model for QoE, the exponential relationship between QoE and network level performance, was then used in further experiments on performance evaluation of OpenID authentication using EAP-SIM. The latter was done to determine the decisive factors for QoE of the authentication method in use. The results from these experiments show that the combination of OpenID and EAP-SIM for authentication over a secure tunnel is not appropriate to use over networks with high delays. The latter implies the need for improvements of the authentication procedure of OpenID using EAP-SIM, which should be addressed in the future. The user model of QoE obtained in this study will even help to quantify the performance aspects of future authentication procedures.

To an end user, Quality of Experience (QoE) matters more than Quality of Service (QoS) because she is the owner of her experience, which is the result of her perception. In recent times, QoE got increasingly much attention from service providers, operators, manufacturers and researchers. Amongst others, they are interested to know how the users perceive the quality of multimedia streaming and how to predict the QoE by measuring network performance parameters. Below the network layer, different access networks can be used, but the internet and transport layers remain the same for everyone on best-effort internet. We highlight a set of possible factors that are contributing towards the QoE, from network via transport to application layer, including applications, codecs, middleware and devices. To investigate the relationship of QoS and QoE, emulation-based experiments were designed. For the purpose of emulation, different shapers are in use by the research community. We selected three popular shapers, NetEm, NISTnet and KauNet, and investigated their emulation capabilities with focus on delay, delay variation and bit rate in order to be able to select the best-suited shaper for future use. Then, we studied the effect of QoS parameters on mobile video QoE. To evaluate the video QoE, user tests were conducted. We observe a much larger sensitivity of users to freezes and their placement within the video than what is predicted by an objective video quality assessment tool that is recommended by the standardisation organization ITU. Furthermore, we investigated the role of codec and device on QoE in view of network-induced problems.

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It was known for a long time that OpenStack has issues with scalability. Peer-to-Peer systems, on the other hand, have proven to scale well without significant reduction of performance. The objectives of this thesis are to study the challenges associated with P2P-enhanced clouds and present solutions for overcoming them. As a case study, we take the architecture of the P2P-enhanced OpenStack implemented at Ericsson that uses the CYCLON P2Pprotocol. We study the OpenStack architecture and P2P technologies and finally propose solutions and provide possibilities in addressing the challenges that are faced by P2P-enhanced OpenStack clouds. We emphasize mainly on a decentralized identity service and management of Virtual machine images. This work also investigates the characterization of P2P architectures for their use in P2P-enhanced OpenStack clouds. The results section shows that the proposed solution enables the existing P2P system to scale beyond what was originally possible. We also show that the P2P-enhanced system performs better than the standard OpenStack. / <p>Ericsson Cloud Research supported this work through the guidance of Dr. Fetahi Wuhib, Dr. Joao Monteiro Soares and Vinay Yadav, Experienced Researchers, Ericsson Cloud Research, Kista, Stockholm.</p>

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