Thesis (M.Sc. (Computer Science)) - Rhodes University, 2008

Mémoire (M.Eng.)-- Université du Québec à Chicoutimi, 1992. / Résumé disponible sur Internet. CaQCU Bibliogr.: f. 142-150. Document électronique également accessible en format PDF. CaQCU

Mémoire (M.Eng.)-- Université du Québec ;a Chicoutimi, 1993. / Résumé disponible sur Internet. CaQCU Document électronique également accessible en format PDF. CaQCU

Thesis (M. Sc. (Computer Science))--Rhodes University, 2006.

The Session Initiation Protocol (SIP) has in recent years become a popular protocol for the exchange of text, voice and video over IP networks. This thesis proposes the use of a class of structured peer to peer protocols - commonly known as Distributed Hash Tables (DHTs) - to provide a SIP overlay with services such as end-point location management and message relay, in the absence of traditional, centralised resources such as SIP proxies and registrars. A peer-to-peer layer named OverCord, which allows the interaction with any specific DHT protocol via the use of appropriate plug-ins, was designed, implemented and tested. This layer was then incorporated into a SIP user agent distributed by NIST (National Institute of Standards and Technology, USA). The modified user agent is capable of reliably establishing text, audio and video communication with similarly modified agents (peers) as well as conventional, centralized SIP overlays.

abstract: Access Networks provide the backbone to the Internet connecting the end-users to the core network thus forming the most important segment for connectivity. Access Networks have multiple physical layer medium ranging from fiber cables, to DSL links and Wireless nodes, creating practically-used hybrid access networks. We explore the hybrid access network at the Medium ACcess (MAC) Layer which receives packets segregated as data and control packets, thus providing the needed decoupling of data and control plane. We utilize the Software Defined Networking (SDN) principle of centralized processing with segregated data and control plane to further extend the usability of our algorithms. This dissertation introduces novel techniques in Dynamic Bandwidth allocation, control message scheduling policy, flow control techniques and Grouping techniques to provide improved performance in Hybrid Passive Optical Networks (PON) such as PON-xDSL, FiWi etc. Finally, we study the different types of software defined algorithms in access networks and describe the various open challenges and research directions. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2015

Orientador: Islene Calciolari Garcia / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Computação / Made available in DSpace on 2018-08-11T15:53:44Z (GMT). No. of bitstreams: 1 Oliveira_MarciliodaSilva_M.pdf: 2563654 bytes, checksum: a5cf71efc67be68a783a10873fd26809 (MD5) Previous issue date: 2006 / Resumo: Arquiteturas Peer-to-Peer (P2P) têm sido uma alternativa bastante atraente para tornar a Internet mais acessível. Desde programas de compartilhamento de conteúdo a sistemas de comunicação têm utilizando esta abordagem de arquitetura e dando importantes contribuições para melhorias nas tecnologias e metodologias relacionadas as redes P2P. Neste contexto, o presente trabalho apresenta a definção da arquitetura de uma rede P2P para distribuição e compartilhamento de componentes de software, visando montar uma rede descentralizada, na qual qualquer participante possa se conectar, fornecer e buscar por componentes de software. Os componentes de software são módulos independentes, com interfaces bem definidas, que podem ser reutilizados em diferentes situações. O reuso de software vem se destacando como grande promessa para aumentar a produtividade no desenvolvimento de sistemas. A aplicação do reuso de software se concentra principalmente na reutilização e integração de partes prontas e previamente testadas. Este trabalho apresenta também a concepção de um modelo de repositório para armazenamento de componentes de software. Estes repositórios podem se comunicar através do protocolo de rede desenvolvido, montando uma rede de compartilhamento P2P. Através da construção da arquitetura, do mecanismo de busca e modelagem dos repositórios, propomos aqui a estrutura fundamental para a criação de redes e sub-redes independentes, visando compartilhar componentes de software entre grupos de pesquisa, universidades, desenvolvedores e empresas. Esta arquitetura constitui a estrutura de distribuição da Rede de Compartilhamento de Componentes de Software (RCCS). A RCCS 'e um projeto de construção de uma rede pública para compartilhamento de componentes, desenvolvido no Laboratório de Inovação Ci&T/Unicam / Abstract: Peer-to-peer (P2P) architectures have become a very attractive alternative to make the Internet more accessible. This approach has been widely used, from content sharing programs through communications systems, which has provided the P2P networks with considerable improvements in the technology and methodologies related. In this context, the current work presents the architecture definition of a decentralized P2P network for distribution and sharing of software components in which any participant can get connected, offer and search for software components. Software components are interdependent modules with well-defined interfaces that can be reused in different situations. Software reuse has been considered the big boom when it comes to productivity in software development. Reusing is related to the integration of ready and previously tested pieces of software. This work also presents the conception of a repository model for storing software components. These repositories can communicate with one another using the custom built network protocol, resulting in a strong and reliable P2P sharing network. Through the architecture definition, the search mechanism and the modeling of the repositories, we propose the fundamental structure for the creation of independent network and sub-networks so as to share software components between research groups, universities and developers. Such architecture constitutes the distribution structure of the Software Component Sharing Network. The project focused on developing this public network for sharing components has been hosted at the Ci&T/Unicamp Innovation Lab / Mestrado / Sistemas Distribuidos / Mestre em Ciência da Computação

This project demonstrates an understanding of how a manufacturing organization can use the methodology of open systems integration to upgrade the design of the network architecture for their manufacturing information system. In upgrading the design of their manufacturing information system's network architecture, a limited application of the system engineering process is used to produce an initial conceptual design. As technology grows, many manufacturing organizations are taking the necessary steps to upgrade their operations to remain competitive in these changing times. This project explores this problem which many manufacturing organizations are experiencing as technology continues to leap frog past its current limitations. Many of the manufacturing organizations which have been in operation for years are having difficulties competing with many of the new manufacturing organizations with their current technologies. / Master of Science

Many emerging mobile networks aim to provide wireless network services without relying on any infrastructure. The main challenge in these networks comes from their self-organized and distributed nature. There is an inherent reliance on collaboration among the participants in order to achieve the aimed functionalities. Therefore, establishing and quantifying trust, which is the driving force for collaboration, is important for applications in mobile networks. This dissertation focuses on evaluating and quantifying trust to stimulate collaboration in mobile networks, introducing uncertainty concepts and metrics, as well as providing the various analysis and applications of uncertainty-aware reputation systems. Many existing reputation systems sharply divide the trust value into right or wrong, thus ignoring another core dimension of trust: uncertainty. As uncertainty deeply impacts a node's anticipation of others' behavior and decisions during interaction, we include it in the reputation system. Specifically, we use an uncertainty metric to directly reflect a node's confidence in the sufficiency of its past experience, and study how the collection of trust information may affect uncertainty in nodes' opinions. Higher uncertainty leads to higher transaction cost and reduced acceptance of communication. We exploit mobility to efficiently reduce uncertainty and to speed up trust convergence. We also apply the new reputation system to enhance the analysis of the interactions among mobile nodes, and present three sample uncertainty-aware applications. We integrate the uncertainty-aware reputation model with game theory tools, and enhance the analysis on interactions among mobile nodes. / Instead of reactively protecting the mobile networks from existing attacks as in the traditional security paradigms, the analysis in this dissertation gives more insights on nodes' rationality in the interaction, which will enable the mechanism design in mobile networks to be security and incentive compatible. Moreover, we present three sample applications, in which we clearly identify the challenges, specifically formalize the problems, and cleverly employ the uncertainty mitigation schemes. These applications show that the uncertainty definition and mitigation schemes can benefit a broad range of applications, including fields such as security, network services, and routing. / by Feng Li. / Vita. / Thesis (Ph.D.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.

Web services intend to provide an application integration technology that can be successfully used over the Internet in a secure, interoperable and trusted manner. Policies are high-level guidelines defining the way an institution conducts its activities. The WS-Policy standard describes how to apply policies of security definition, enforcement of access control, authentication and logging. WS-Trust defines a security token service and a trust engine which are used by web services to authenticate other web services. Using the functions defined in WS-Trust, applications can engage in secure communication after establishing trust. BPEL is a language for web service composition that intends to provide convenient and effective means for application integration over the Internet. We address security considerations in BPEL and how to enforce them, as well as its interactions with other web services standards such as WS-Security and WS-Policy. / by Ola Ajaj. / Thesis (M.S.C.S.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.