67,532 research outputs found

    A Dynamic Multimedia User-Weight Classification Scheme for IEEE_802.11 WLANs

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    In this paper we expose a dynamic traffic-classification scheme to support multimedia applications such as voice and broadband video transmissions over IEEE 802.11 Wireless Local Area Networks (WLANs). Obviously, over a Wi-Fi link and to better serve these applications - which normally have strict bounded transmission delay or minimum link rate requirement - a service differentiation technique can be applied to the media traffic transmitted by the same mobile node using the well-known 802.11e Enhanced Distributed Channel Access (EDCA) protocol. However, the given EDCA mode does not offer user differentiation, which can be viewed as a deficiency in multi-access wireless networks. Accordingly, we propose a new inter-node priority access scheme for IEEE 802.11e networks which is compatible with the EDCA scheme. The proposed scheme joins a dynamic user-weight to each mobile station depending on its outgoing data, and therefore deploys inter-node priority for the channel access to complement the existing EDCA inter-frame priority. This provides efficient quality of service control across multiple users within the same coverage area of an access point. We provide performance evaluations to compare the proposed access model with the basic EDCA 802.11 MAC protocol mode to elucidate the quality improvement achieved for multimedia communication over 802.11 WLANs.Comment: 15 pages, 8 figures, 3 tables, International Journal of Computer Networks & Communications (IJCNC

    Localism, Self-Interest, and the Tyranny of the Favored Quarter: Addressing the Barriers to New Regionalism

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    This article argues that our nation\u27s ideological commitment to decentralized local governance has helped to create the phenomenon of the favored quarter. Localism, or the ideological commitment to local governance, has helped to produce fragmented metropolitan regions stratified by race and income. This fragmentation produces a collective action problem or regional prisoner\u27s dilemma that is well-known in the local governance literature

    Understanding the role of performance targets in transport policy

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    The measurement of performance in the public sector has become increasingly important in recent years and it is now commonplace for transport organisations, and local and national governments, to publish performance goals for service supply and quality. Such commitments, when time referenced, are known as targets. This paper explain how changes in management style, consumer rights legislation, contractual obligations and other factors have combined to make management-by targets increasingly common in the public sector. The advantages and disadvantages of management-by-targets are illustrated through discussion of the processes and experience of setting transport targets in UK national transport policy. We conclude that while some of the targets have had a significant impact on policy makers, managers and their agents, the effects have not always been as intended
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