144,210 research outputs found

    A SECURE GROUP KEY AGREEMENT WITH LOCAL CONNECTIVITY USING MULTICAST KEY MANAGEMENT

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    In this paper, we study Group key Agreement which mean multiple parties want to create a common secret key to be used to exchange information securely. The group key agreement with an arbitrary connectivity graph, where each user is only aware of his neighbor and has no information about the existence of other users. Further, he has no information about the network topology. We implement the existing system with more efficient manner and provide a multicast key generation protocol. We replace the Diffie-Hellman key exchange protocol by a new multicast key exchange protocol that can work with One to One and One to Many functionality. We also tend to implement a strong symmetric key encryption for improving file security in the system

    A Novel Joint Brain Network Analysis Using Longitudinal Alzheimer's Disease Data.

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    There is well-documented evidence of brain network differences between individuals with Alzheimer's disease (AD) and healthy controls (HC). To date, imaging studies investigating brain networks in these populations have typically been cross-sectional, and the reproducibility of such findings is somewhat unclear. In a novel study, we use the longitudinal ADNI data on the whole brain to jointly compute the brain network at baseline and one-year using a state of the art approach that pools information across both time points to yield distinct visit-specific networks for the AD and HC cohorts, resulting in more accurate inferences. We perform a multiscale comparison of the AD and HC networks in terms of global network metrics as well as at the more granular level of resting state networks defined under a whole brain parcellation. Our analysis illustrates a decrease in small-worldedness in the AD group at both the time points and also identifies more local network features and hub nodes that are disrupted due to the progression of AD. We also obtain high reproducibility of the HC network across visits. On the other hand, a separate estimation of the networks at each visit using standard graphical approaches reveals fewer meaningful differences and lower reproducibility

    Internet Governance : exploring the development link

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    This paper seeks to explore the issues of Internet governance from a development perspective. The WSIS process and the report of the UN Working group on Internet Governance provide an initial framework within which to develop the issues. These issues not only concern the equitable distribution of Internet resources and the ways in which a secure and reliable function of the Internet can be achieved, but also include issues of multi-lingualism and local content as well as the institutional setting of Internet governance mechanisms and participation. The paper observers that realising the contribution of the Internet to development goals requires a shift in policy focus away from supply side initiatives in the telecommunications sector to more co-ordinated approaches

    Fixed-Connectivity Membranes

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    The statistical mechanics of flexible surfaces with internal elasticity and shape fluctuations is summarized. Phantom and self-avoiding isotropic and anisotropic membranes are discussed, with emphasis on the universal negative Poisson ratio common to the low-temperature phase of phantom membranes and all strictly self-avoiding membranes in the absence of attractive interactions. The study of crystalline order on the frozen surface of spherical membranes is also treated.Comment: Chapter 11 in "Statistical mechanics of Membranes and Surfaces", ed. by D.R. Nelson, T. Piran and S. Weinberg (World Scientific, Singapore, 2004); 25 pages with 26 figures (high resolution figures available from author

    Consensus, Cohesion and Connectivity

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    Social life clusters into groups held together by ties that also transmit information. When collective problems occur, group members use their ties to discuss what to do and to establish an agreement, to be reached quick enough to prevent discounting the value of the group decision. The speed at which a group reaches consensus can be predicted by the algebraic connectivity of the network, which also imposes a lower bound on the group's cohesion. This specific measure of connectivity is put to the test by re-using experimental data, which confirm the prediction
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