49,930 research outputs found

    A sustainable model for ICT capacity building in developing countries

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    System administrators are often asked to apply their professional expertise in unusual situations, or under tight resource constraints. What happens, though, when the “situation” is a foreign country with only basic technical infrastructure, and the task is to bauild systems which are able to survive and grow in these over-constrained environments? In this paper we report on our experiences in two very different countries – Cuba and Ethiopia – where we ran a number of ICT projects. In those projects we assisted local universities to upgrade their ICT infrastructure and services. This included skills and process building for local system administrators. Based on our experiences we formulate a model for sustainable ICT capacity building. We hope this model will be useful for other organizations doing similar projects

    Reliable Messaging to Millions of Users with MigratoryData

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    Web-based notification services are used by a large range of businesses to selectively distribute live updates to customers, following the publish/subscribe (pub/sub) model. Typical deployments can involve millions of subscribers expecting ordering and delivery guarantees together with low latencies. Notification services must be vertically and horizontally scalable, and adopt replication to provide a reliable service. We report our experience building and operating MigratoryData, a highly-scalable notification service. We discuss the typical requirements of MigratoryData customers, and describe the architecture and design of the service, focusing on scalability and fault tolerance. Our evaluation demonstrates the ability of MigratoryData to handle millions of concurrent connections and support a reliable notification service despite server failures and network disconnections

    End-to-end QoE optimization through overlay network deployment

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    In this paper an overlay network for end-to-end QoE management is presented. The goal of this infrastructure is QoE optimization by routing around failures in the IP network and optimizing the bandwidth usage on the last mile to the client. The overlay network consists of components that are located both in the core and at the edge of the network. A number of overlay servers perform end-to-end QoS monitoring and maintain an overlay topology, allowing them to route around link failures and congestion. Overlay access components situated at the edge of the network are responsible for determining whether packets are sent to the overlay network, while proxy components manage the bandwidth on the last mile. This paper gives a detailed overview of the end-to-end architecture together with representative experimental results which comprehensively demonstrate the overlay network's ability to optimize the QoE

    Proposal for an IMLS Collection Registry and Metadata Repository

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    The University of Illinois at Urbana-Champaign proposes to design, implement, and research a collection-level registry and item-level metadata repository service that will aggregate information about digital collections and items of digital content created using funds from Institute of Museum and Library Services (IMLS) National Leadership Grants. This work will be a collaboration by the University Library and the Graduate School of Library and Information Science. All extant digital collections initiated or augmented under IMLS aegis from 1998 through September 30, 2005 will be included in the proposed collection registry. Item-level metadata will be harvested from collections making such content available using the Open Archives Initiative Protocol for Metadata Harvesting (OAI PMH). As part of this work, project personnel, in cooperation with IMLS staff and grantees, will define and document appropriate metadata schemas, help create and maintain collection-level metadata records, assist in implementing OAI compliant metadata provider services for dissemination of item-level metadata records, and research potential benefits and issues associated with these activities. The immediate outcomes of this work will be the practical demonstration of technologies that have the potential to enhance the visibility of IMLS funded online exhibits and digital library collections and improve discoverability of items contained in these resources. Experience gained and research conducted during this project will make clearer both the costs and the potential benefits associated with such services. Metadata provider and harvesting service implementations will be appropriately instrumented (e.g., customized anonymous transaction logs, online questionnaires for targeted user groups, performance monitors). At the conclusion of this project we will submit a final report that discusses tasks performed and lessons learned, presents business plans for sustaining registry and repository services, enumerates and summarizes potential benefits of these services, and makes recommendations regarding future implementations of these and related intermediary and end user interoperability services by IMLS projects.unpublishednot peer reviewe

    An Infrastructure for the Dynamic Distribution of Web Applications and Services

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    This paper presents the design and implementation of an infrastructure that enables any Web application, regardless of its current state, to be stopped and uninstalled from a particular server, transferred to a new server, then installed, loaded, and resumed, with all these events occurring "on the fly" and totally transparent to clients. Such functionalities allow entire applications to fluidly move from server to server, reducing the overhead required to administer the system, and increasing its performance in a number of ways: (1) Dynamic replication of new instances of applications to several servers to raise throughput for scalability purposes, (2) Moving applications to servers to achieve load balancing or other resource management goals, (3) Caching entire applications on servers located closer to clients.National Science Foundation (9986397

    Enhancing the environmental sustainability of IT

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    Emerging technologies for learning report - Article exploring green I
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