Global ETD Search

11	Uma arquitetura baseada em espaço de tuplas para redes IMS. / A tuple space-based architecture for IMS networks. Rondini, Rogério Augusto 23 November 2012 (has links) A arquitetura IP Multimedia Subsystem, proposta pelo consórcio 3rd Generation Partnership Project como base para o suporte à convergência entre telefonia móvel e a Internet, define uma série de elementos arquiteturais, entre os quais, o componente Call Session Control Function e o protocolo Session Initiation Protocol. Session Initiation Protocol é um protocolo da camada de aplicação utilizado para estabelecer, modificar e terminar sessões multimídia entre dispositivos. Em redes baseadas na arquitetura IP Multimedia Subsystem, o Session Initiation Protocol é o responsável pela comunicação entre dispositivos e a rede, e entre os componentes responsáveis pelo gerenciamento de sessão. Nos últimos anos, estudos detectaram degradação de desempenho em redes baseadas na arquitetura IP Multimedia Subsystem em função das características centralizadas do Session Initiation Protocol e dos componentes de gerenciamento de sessão. Este trabalho apresenta uma arquitetura distribuída para redes baseadas em IP Multimedia Subsystem, tendo como fundamento o paradigma de computação paralela baseado em espaço de tuplas onde os servidores são organizados em uma rede P2P, com objetivo de prover uma infraestrutura escalável e tolerante a falhas. A validação da arquitetura em termos de desempenho e escalabilidade se deu através de modelagem formal e simulação com Redes de Petri Coloridas. / The IP Multimedia Subsystem architecture, proposed by the 3rd Generation Partnership Project consortium as basis to support the convergence between mobile networks and the Internet, defines a set of architectural elements, among them, the Call Session Control Function and the Session Initiation Protocol. The Session Initiation Protocol is an application layer protocol used to establish, modify and terminate sessions between devices. On the IP multimedia subsystem based network, the Session Initiation Protocol play a key role on the communication between devices and the network, and between session management components. In the last years, studies have detected a performance bottleneck on IP multimedia subsystem networks due to centralized characteristic of the Session Initiation Protocol and in Session Control components. This work shows a distributed architecture for IP Multimedia Subsystem networks based on the tuple space paradigm, and the servers structured in a P2P network, aiming to achieve a scalable and fault-tolerant infrastructure. The validation of the architecture on the performance and scalability took place through the Coloured Petri Net formal modeling and simulation. Coloured Petri Nets Espaço de tuplas IMS network Modelagem e simulação Modeling and simulation P2P network Protocolo SIP Redes de Petri Coloridas Redes IMS Redes P2P SIP protocol Tuple space
12	Uma arquitetura baseada em espaço de tuplas para redes IMS. / A tuple space-based architecture for IMS networks. Rogério Augusto Rondini 23 November 2012 (has links) A arquitetura IP Multimedia Subsystem, proposta pelo consórcio 3rd Generation Partnership Project como base para o suporte à convergência entre telefonia móvel e a Internet, define uma série de elementos arquiteturais, entre os quais, o componente Call Session Control Function e o protocolo Session Initiation Protocol. Session Initiation Protocol é um protocolo da camada de aplicação utilizado para estabelecer, modificar e terminar sessões multimídia entre dispositivos. Em redes baseadas na arquitetura IP Multimedia Subsystem, o Session Initiation Protocol é o responsável pela comunicação entre dispositivos e a rede, e entre os componentes responsáveis pelo gerenciamento de sessão. Nos últimos anos, estudos detectaram degradação de desempenho em redes baseadas na arquitetura IP Multimedia Subsystem em função das características centralizadas do Session Initiation Protocol e dos componentes de gerenciamento de sessão. Este trabalho apresenta uma arquitetura distribuída para redes baseadas em IP Multimedia Subsystem, tendo como fundamento o paradigma de computação paralela baseado em espaço de tuplas onde os servidores são organizados em uma rede P2P, com objetivo de prover uma infraestrutura escalável e tolerante a falhas. A validação da arquitetura em termos de desempenho e escalabilidade se deu através de modelagem formal e simulação com Redes de Petri Coloridas. / The IP Multimedia Subsystem architecture, proposed by the 3rd Generation Partnership Project consortium as basis to support the convergence between mobile networks and the Internet, defines a set of architectural elements, among them, the Call Session Control Function and the Session Initiation Protocol. The Session Initiation Protocol is an application layer protocol used to establish, modify and terminate sessions between devices. On the IP multimedia subsystem based network, the Session Initiation Protocol play a key role on the communication between devices and the network, and between session management components. In the last years, studies have detected a performance bottleneck on IP multimedia subsystem networks due to centralized characteristic of the Session Initiation Protocol and in Session Control components. This work shows a distributed architecture for IP Multimedia Subsystem networks based on the tuple space paradigm, and the servers structured in a P2P network, aiming to achieve a scalable and fault-tolerant infrastructure. The validation of the architecture on the performance and scalability took place through the Coloured Petri Net formal modeling and simulation. Espaço de tuplas Modelagem e simulação Protocolo SIP Redes de Petri Coloridas Redes IMS Redes P2P Coloured Petri Nets IMS network Modeling and simulation P2P network SIP protocol Tuple space
13	DESIGN OF CROWD-SCALE MULTI-PARTY TELEPRESENCE SYSTEM WITH DISTRIBUTED MULTIPOINT CONTROL UNIT BASED ON PEER TO PEER NETWORK Hossain, Md Amjad 02 December 2020 (has links) No description available. Computer Science Peer to peer video conferencing P2P Network Multiparty Telepresence Crowd-Scale Multipoint Control Unit Distributed MCU Role-based stream prioritization GAncestor ZePoP Leader Election overcrowding stream collection and distribution tree
14	Rozbor a návrh aplikace pro digitální měnu Bitcoin / Analysis and implementation of application for digital currency Bitcoin DRDÁK, František January 2015 (has links) The thesis is focused on the topic of virtual cryptocurrency Bitcoin. The theoretical part is divided into several chapters. First of all, there is a chapter containing basic information about the currency's history, its development to the present, as well as principles of operation of this currency. Because it is a currency based on cryptographic principles next chapter summarizing cryptographic techniques, which is necessary to know for subsequent analysis of this currency. In other parts is elaborated a detailed analysis of the principles of Bitcoin. The main point of this analysis is a system of transactions, decentralized history, then joining the transactions into blocks and in the end creating blockchain. It also explains the principle of P2P networks. The practical part of this work focuses on the analysis and design of payment applications for mobile devices. There used open-source libraries such BitcoinJ. The application is developed in Java programming language with plugin for portable devices, which work under the operating system Android. For the purposes of analysis and design of graphical user interface is used UML diagrams. The specification of the UML diagrams was utilized by freely available graphics software and the result is also included in this work.
15	Distribution multi-contenus sur Internet / Content distribution over Internet Mnie Filali, Imane 27 September 2016 (has links) Dans cette thèse, nous nous sommes intéressés aux protocoles pair-à-pair (P2P), qui représentent une solution prometteuse pour la diffusion et le partage de données à faible coût sur Internet. Nous avons mené, dans un premier temps, une étude comportementale de différents protocoles P2P pour le partage de fichier (distribution de contenus sans contrainte de temps) puis le live. Dans la première étude centréesur le partage de fichier, nous avons montré l’impact d’Hadopi sur le comportement des utilisateurs et discuté l’efficacité des protocoles en fonction du contenu et l’efficacité protocolaire, en se basant sur les choix des utilisateurs. BitTorrent s’est nettement démarqué au cours de cette étude, notamment pour les grands contenus. En ce qui concerne le live, nous nous sommes intéressés à la qualité de servicedu réseau de distribution live Sopcast, car plus de 60% des événements live diffusés en P2P le sont sur ce réseau. Notre analyse approfondie de ces deux modes de distribution nous a fait nous recentrer sur BitTorrent, qui est à la base de tous les protocoles P2P Live, et est efficace en partage de fichier et complètement open source. Dans la seconde partie de la thèse, nous avons proposé et implémenté dansun environnement contrôlé un nouveau protocole sur la base de BitTorrent avec des mécanismes protocolaires impliquant tous les pairs dans la gestion du réseau. Ces nouveaux mécanismes permettent d’augmenter l’efficacité du protocole via une meilleure diffusion, tant pour le live que le partage de fichier, de métadonnées (la pièce la plus rare) et via une méthode dite de push, par laquelle un client va envoyer du contenu aux pairs les plus dans le besoin / In this study, we focused on peer-to-peer protocols (P2P), which represent a promising solution for data dissemination and content delivery at low-cost in the Internet. We performed, initially, a behavioral study of various P2P protocols for file sharing (content distribution without time constraint) and live streaming. Concerning file sharing, we have shown the impact of Hadopi on users’ behavior and discussed the effectiveness of protocols according to content type, based on users’ choice. BitTorrent appeared as the most efficient approach during our study, especially when it comes to large content. As for streaming, we studied the quality of service of Sopcast, a live distribution network that accounts for more than 60% of P2P broadcast live events. Our in-depth analysis of these two distributionmodes led us to focus on the BitTorrent protocol because of its proven efficiency in file sharing and the fact that it is open source. In the second part of the thesis, we proposed and implemented a new protocol based on BitTorrent, in a controlled environment. The modifications that we proposed allow to increase the efficiency of the protocol through improved dissemination of metadata (the rarest piece), both for live and file sharing. An enhanced version is introduced with a push method, where nodes that lag behind receive an extra service so as to improve the overall performance Réseaux P2P Protocole P2P Performance protocole Loi anti-piraterie Partage de fichier Partage de données Partage de ressources Qualité des métadonnées Pair actif Pair intelligent Gestion collaborative Gestion réseau Sécurité réseau Vision locale Vision globale BitTorrent Sopcast EDonkey Gnutella Peer-to-peer computing P2P network approach P2P Protocols Protocols performance Protocol efficiency Anti-piracy laws File sharing Streaming Live sharing Data sharing Ressources sharing Meta-data quality Collaborative management Active peer Peer intelligent Network management Network security Local vision Global vision BitTorrent EDonkey Sopcast Gnutella

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