Thesis (M.Sc.)--Memorial University of Newfoundland, 2004. / Restricted until May 2005. Bibliography: leaves 76-92.

[pt] Este trabalho descreve o projeto de um Sistema Remoto de Entrada e Saída de Dados (Remote Job Entry-RJE). O sistema desenvolvido emula a estação IBM/2780 do RJE. A emulação é obtida por software de microcomputador (MCPUC-80, INTEL 8080). A abordagem teórica inclui, em detalhes, Sistemas de Comunicação de Dados e Protocolos de Comunicação, e em particular, o protocolo BSC (Binary Synchronours Communication) que foi implementado neste projeto. A implementação é descrita em termos de requisitos, adaptações e métodos empregados no processo de emulação do IBM/2780 por sistema de microcomputador. / [en] This paper discribes de development of a Remote Job Entry System. The system developed is an emulation version of do IBM/2780, RJE station. the emulation process is by microcomputer software and hardware (MCPUC-80, INTEL 8080). The paper includes theoretical aspects of Data Communications Systems and Protocols, specialy of the Bunary Synchronous Communications protocol, which was used in this work. The implementation also describes the requirements, methods and adaptations that were necessary in the emulation process.

M.A. / The anonymity associated with Computer Mediated Communication has formed the basis of an assumption that fantasy is a prominent feature of interactions taking place via the internet. Some of the literature argues that through fantasy identities all participants are able to become whoever they want to be, creating new virtual communities where equality between members is fundamental in their interactions. The findings of this dissertation suggest, however, that anonymity is limited by the reasons for chat room participation. Further, all the members are not equal, with a clear hierarchy evident as one logs onto the site. This study also argues that the concept of ‘virtual communities’ is not an accurate description of what occurs in chat rooms. The examination of chat rooms as ‘new meeting places’ for real identities is expected to generate more accurate theoretical postulations, in which the significance of the linkages between on- and offline realities is acknowledged. The extended case method was used to examine a chat room, known as Conversations, to investigate the linkages between online participation patterns and offline realities. Issues concerning identity and identity formation informed the principal motives in the selection of a research design that allowed the researcher extensive exposure to the members of this chat room. Since the emphasis was on the discovery of the meaning the chatters themselves attached to their participation, it was important to use a comprehensive research design. To this effect, three complementary data gathering techniques were employed; namely: virtual participant observation, face-to-face participant observation and in-depth interviews. Through this innovative research design the linkages between social opportunities, individual motivation and chat room participation were illuminated. / Meera Ichharam Chris Bolsmann

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A distributed application may be considered as a set of nodes which are spread across the network, and need to communicate with each other. The design and implementation of these distributed applications is greatly simplified using Group Communication Systems (GCSs) which provide multipoint to multipoint communication. Hence, GCSs can be used as building blocks for implementing distributed applications. The GCS is responsible for reliable delivery of group messages and management of group membership. The peer-to-peer model and the client-server model are the two models of distributed systems for implementing GCSs. In this thesis, our focus is on improving the capability of GCS based on the client-server model. Security is an important requirement of many distributed applications. For such applications, security has to be provided m the GCS itself. The security of a GCS includes confidentiality, authentication and non-repudiation of messages, and ensuring that the GCS is properly meeting its guarantees. The complexity and cost of implementation of the above three types of security guarantees greatly depend on whether the GCS servers are trusted by the group members or not. Making use of the GCS services provided by untrusted GCS servers becomes necessary when the GCS servers are managed by a third party. In this thesis, we have proposed algorithms for ensuring the above three security guarantees for GCSs in which servers are not trusted. As part of the solution, we have proposed a new digital multisignature scheme which allows group members to verify that a message has indeed been signed by all group members. The various group key management algorithms proposed in literature differ from each other with respect to the following four metrics: communication overhead, computational overhead, storage at each member and distribution of load among group members. We identify the need for a distributed group key management algorithm which minimizes the computational overhead on group members and propose an algorithm to achieve it.

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Diss. (sammanfattning) Linköping : Linköpings universitet, 2006. / Härtill 5 uppsatser.

När det stod klart att antalet adresser i ipv4 inte skulle räcka, togs ipv6 fram. Med nya funktioner som hade anpassats till den infrastruktur som hade byggts upp världen runt så fanns det nu en ersättare till ipv4. Men skillnaderna är stora och protokollen är i sig inte lika varandra alls, framför allt inte när man tittar på inbygda funktioner. En av dessa nya funktioner i ipv6 är det som kallas för Prefix delegation, ett enkelt och smidigt sätt att per automatik dela ut delar av ett större nät till mindre nät. Även om det finns enkla och smidiga sätt att genomföra detta på så är inte all infrastuktur så enkel. Det gör att denna typ av funktioner kommer varvas med routes, både statiska och dynamiska. För att få en förståelse för hur detta kan skilja sig åt har vi tittat på en översikt av hur infrastrukturen kan se ut och sedan testat hur man skulle kunna lösa adresseringen genom en automatiserad process och en statisk process. Resultatet visar att den automatiserade lösningen kräver lite mer förarbete och specificerad utrustning, men att arbetet därefter blir lätt att kontrollera, felsöka och dokumentera. Den statiska processen är mer rakt på sak och kräver ingen speciell utrustning, däremot kommer det bli svårt att kontrollera, felsöka och dokumentera då minsta förändring kan kräva mycket arbete där risken för komplikationer är stor. / When it became clear that the number of ipv4 addresses would not be enough, ipv6 was developed. With new features that had been adapted to the infrastructure that had been built up around the world, there was now a replacement for ipv4. But the differences are many and the protocols are not alike at all, especially when looking at the built-in functions. One of these new features in ipv6 is called Prefix Delegation, a simple and convenient way to automatically distribute parts of a larger network into smaller networks. Although there are simple and flexible way to implement this, the existing infrastructure of the Internet may not be so simple. The complexity of the infrastructure forces us to use a variety of routes, both static and dynamic. To get an understanding of how this can differ, we looked at an overview of how the infrastructure might look like and then tested how to solve the addressing through an automated process and a static process. The results shows that the automated solution requires a little more preparation and specified equipment, but the work then becomes easy to control, debug, and document. The static process is more straightforward and requires no special equipment, however, it will be difficult to control, debug, and document where the slightest change can require a lot of work where the risk of complications is great.

[pt] Com o advento dos microprocessadores e a crescente diminuição do preço dos circuitos integrados LSI (Large Scale Integration) houve um aumento da utilização de computadores de pequeno porte para a realização de tarefas locais e especificas. Tornou-se, então, economicamente viável a utilização, em número cada vez maior, de redes interligando computadores de pequeno porte. O presente trabalho contém um estudo dos diversos problemas decorrentes do projeto de redes natureza, apresentando soluções adequadas a cada caso. / [en] Theappearance of microprocessors and the lowering costs LSI (Large Scale Integration) technology brought and increaase in the use of low-size computers for dedicated applications. So, it became economically feasible to interconnect such low-size computers, creating a network. A study of various problems arising from the design of such networks is presented, as well as adequated solutions for each case.

No description available.