7,491 research outputs found

    A new multipath routing approach to enhancing TCP security in ad hoc wireless networks

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    In a typical mobile ad hoc network, mobile computing devices wander autonomously and communicate via temporary links in a self-organized computing system without any central administrator or infrastructure support. To support truly ad hoc impromptu communication among such uncoordinated devices, a data multipath routing algorithm can be used because there is no need to rely on a centralized encryption facility (e.g., a PKI server) or complicated distributed keying protocols. In this paper, we propose a data multipath routing algorithm called Multipath TCP Security (MTS) to enhance the data security. In MTS, the source node adaptively chooses the available routes rather than exhaustively testing the "stored routes" one by one. Simulation results show that our algorithm provides a reasonably good level of security and performance. © 2005 IEEE.published_or_final_versio

    Discovering multiple resource holders in query-incentive networks

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    Session - Content Distribution and Peer-to-Peer NetworksIn this paper, we study the problem of discovering multiple resource holders and how to evaluate a node's satisfaction in query incentive networks. Utilizing an acyclic tree, we show that query propagation has a nature of exponential start, polynomial growth, and eventually becoming a constant. We model the query propagation as an extensive game, obtain nodes' greedy behaviors from Nash equilibrium analysis, and show the impairment of greedy behaviors via a repeated Prisoner's Dilemma. We demonstrate that cooperation enforcement is required to achieve the optimal state of resource discovery. © 2011 IEEE.published_or_final_versionThe 8th IEEE Consumer Communications and Networking Conference (CCNC 2011), Las Vegas, NV., 9-12 January 2011. In Proceedings of the 8th CCNC, 2011, p. 1000-100

    Planar hexagonal meshing for architecture

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    Implementation of secondary stroke prevention protocol for ischaemic stroke patients in primary care

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    Design of reflective filters based on organic materials using genetic algorithms

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    In this work we propose a genetic algorithm for the design of reflective filters consisting of organic materials. The algorithm chooses the materials of the layers from the list of available materials and chooses their thickness in order to obtain optimal reflectance characteristics. The wavelength dependence of the refractive index and the coefficient of extinction of the layers is taken into account.published_or_final_versio

    Study of psi(2S) decays to X J/psi

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    Using J/psi -> mu^+ mu^- decays from a sample of approximately 4 million psi(2S) events collected with the BESI detector, the branching fractions of psi(2S) -> eta J/psi, pi^0 pi^0 J/psi, and anything J/psi normalized to that of psi(2S) -> pi^+ pi^- J/psi are measured. The results are B(psi(2S) -> eta J/psi)/B(psi(2S) -> pi^+ pi^- J/psi) = 0.098 \pm 0.005 \pm 0.010, B(psi(2S) -> pi^0 pi^0 J/psi)/B(psi(2S) -> pi^+ pi^- J/psi) = 0.570 \pm 0.009 \pm 0.026, and B(psi(2S) -> anything J/psi)/B(psi(2S) -> pi^+ pi^- J/psi) = 1.867 \pm 0.026 \pm 0.055.Comment: 13 pages, 8 figure

    Cobalt chloride pretreatment promotes cardiac differentiation of human embryonic stem cells under atmospheric oxygen level

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    Our previous study demonstrated the direct involvement of the HIF-1α subunit in the promotion of cardiac differentiation of murine embryonic stem cells (ESCs). We report the use of cobalt chloride to induce HIF-1α stabilization in human ESCs to promote cardiac differentiation. Treatment of undifferentiated hES2 human ESCs with 50μM cobalt chloride markedly increased protein levels of the HIF-1α subunit, and was associated with increased expression of early cardiac specific transcription factors and cardiotrophic factors including NK2.5, vascular endothelial growth factor, and cardiotrophin-1. When pretreated cells were subjected to cardiac differentiation, a notable increase in the occurrence of beating embryoid bodies and sarcomeric actinin-positive cells was observed, along with increased expression of the cardiac-specific markers, MHC-A, MHC-B, and MLC2V. Electrophysiological study revealed increased atrial-and nodal-like cells in the cobalt chloride-pretreated group. Confocal calcium imaging analysis indicated that the maximum upstroke and decay velocities were significantly increased in both noncaffeine and caffeine-induced calcium transient in cardiomyocytes derived from the cobalt chloride-pretreated cells, suggesting these cells were functionally more mature. In conclusion, our study demonstrated that cobalt chloride pretreatment of hES2 human ESCs promotes cardiac differentiation and the maturation of calcium homeostasis of cardiomyocytes derived from ESCs. © 2011 Mary Ann Liebert, Inc.published_or_final_versio

    First observation of psi(2S)-->K_S K_L

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    The decay psi(2S)-->K_S K_L is observed for the first time using psi(2S) data collected with the Beijing Spectrometer (BESII) at the Beijing Electron Positron Collider (BEPC); the branching ratio is determined to be B(psi(2S)-->K_S K_L) = (5.24\pm 0.47 \pm 0.48)\times 10^{-5}. Compared with J/psi-->K_S K_L, the psi(2S) branching ratio is enhanced relative to the prediction of the perturbative QCD ``12%'' rule. The result, together with the branching ratios of psi(2S) decays to other pseudoscalar meson pairs (\pi^+\pi^- and K^+K^-), is used to investigate the relative phase between the three-gluon and the one-photon annihilation amplitudes of psi(2S) decays.Comment: 5 pages, 4 figures, 2 tables, submitted to Phys. Rev. Let
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