161,647 research outputs found

    A brokerage system for enhancing wireless access

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    This paper contributes to the management of a network infrastructure formed by distinct wireless access technologies, which are administered by several cooperating mobile operators. These wireless technologies may cover a public area, which at specific times of the day are overwhelmed by a large number of users. A new management solution is proposed that controls the heterogeneous network infrastructure in a distributed way, using policies and metrics, and ensuring a Quality of Service (QoS) level associated with each terminal connection. The QoS level is supported through a novel, vertical and dynamic aggregation of performance information about the wireless access, originated at distinct technologies. A closed innovative control loop among a flexible brokerage service in the network, and agents at the mobile terminals, counteracts any abnormal data load. This allows the terminals to make well-informed decisions about their connections to improve on the QoS offered to the application layer. In this way, depending on the management policies of the brokerage service and the quality metrics, wireless access technologies that by default only offer a best-effort connection service can be enhanced in a very straightforward way. The obtained results highlight the advantages for using this new distributed solution to manage the heterogeneous network infrastructure in several distinct usage scenarios.info:eu-repo/semantics/acceptedVersio

    Efficient algorithm for mobile multicast using anycast group

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    The authors present a novel and efficient multicast algorithm that aims to reduce delay and communication cost for the registration between mobile nodes and mobility agents and solicitation for foreign agent services based on the mobile IP. The protocol applies anycast group technology to support multicast transmissions for both mobile nodes and home/foreign agents. Mobile hosts use anycast tunnelling to connect to the nearest available home/foreign agent where an agent is able to forward the multicast messages by selecting an anycast route to a multicast router so as to reduce the end-to-end delay. The performance analysis and experiments demonstrated that the proposed algorithm is able to enhance the performance over existing remote subscription and bidirectional tunnelling approaches regardless of the locations of mobile nodes/hosts<br /

    Adam Smith goes mobile : managing services beyond 3G with the digital marketplace

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    The next generation of mobile communications systems is expected to offer new business opportunities to existing and new market players. A market-based middleware framework has been recently proposed whereby service providers, independent of network operators, are able to tender online service contracts to network operators in a dynamic and competitive manner. This facilitates a seamless service provision over disparate networks in a consumer-centric manner. Service providers select network bearers according to the network operators' ability to meet the QoS target, which in turn is influenced, among other things, by user's price and quality requirements. The benefits of this proposal are the complementarity of numerous network resources, the decoupling of services and networks in a self-organising distributed environment, and increased competition to consumers’ advantag

    Digital Ecosystems: Ecosystem-Oriented Architectures

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    We view Digital Ecosystems to be the digital counterparts of biological ecosystems. Here, we are concerned with the creation of these Digital Ecosystems, exploiting the self-organising properties of biological ecosystems to evolve high-level software applications. Therefore, we created the Digital Ecosystem, a novel optimisation technique inspired by biological ecosystems, where the optimisation works at two levels: a first optimisation, migration of agents which are distributed in a decentralised peer-to-peer network, operating continuously in time; this process feeds a second optimisation based on evolutionary computing that operates locally on single peers and is aimed at finding solutions to satisfy locally relevant constraints. The Digital Ecosystem was then measured experimentally through simulations, with measures originating from theoretical ecology, evaluating its likeness to biological ecosystems. This included its responsiveness to requests for applications from the user base, as a measure of the ecological succession (ecosystem maturity). Overall, we have advanced the understanding of Digital Ecosystems, creating Ecosystem-Oriented Architectures where the word ecosystem is more than just a metaphor.Comment: 39 pages, 26 figures, journa
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