32,354 research outputs found

    Synchronization in an array of linearly stochastically coupled networks with time delays

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    This is the post print version of the article. The official published version can be obtained from the link - Copyright 2007 Elsevier LtdIn this paper, the complete synchronization problem is investigated in an array of linearly stochastically coupled identical networks with time delays. The stochastic coupling term, which can reflect a more realistic dynamical behavior of coupled systems in practice, is introduced to model a coupled system, and the influence from the stochastic noises on the array of coupled delayed neural networks is studied thoroughly. Based on a simple adaptive feedback control scheme and some stochastic analysis techniques, several sufficient conditions are developed to guarantee the synchronization in an array of linearly stochastically coupled neural networks with time delays. Finally, an illustrate example with numerical simulations is exploited to show the effectiveness of the theoretical results.This work was jointly supported by the National Natural Science Foundation of China under Grant 60574043, the Royal Society of the United Kingdom, the Natural Science Foundation of Jiangsu Province of China under Grant BK2006093, and International Joint Project funded by NSFC and the Royal Society of the United Kingdom

    Scheduling delay-sensitive and best-effort traffics in wireless networks

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    In this paper we propose a novel wireless scheduling algorithm for delay-sensitive (DS) and best-effort (BE) traffics. Unlike the majority of the previous wireless scheduling, where the wireless links are modeled as having only two states, our algorithm is applicable to links with multiple states. For DS flows, the algorithm is capable of providing statistical delay violation bounds. Such bounds are derived, analytically, using the idea of the statistical service envelope. For BE flows, we propose a new notion of fairness, called long-term link-quality-weighted outcome-fair, which we believe is more suited to wireless networks than pure outcome-fair or effortfair. The algorithm achieves a balance between bandwidth efficiency requirement and fairness requirement, and guarantees minimal goodput levels for BE flows.published_or_final_versio

    Arithmetic purity of strong approximation for semi-simple simply connected groups

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    In this article we establish the arithmetic purity of strong approximation for certain semi-simple simply connected kk-simple linear algebraic groups and their homogeneous spaces over a number field kk. For instance, for any such group GG and for any open subset UU of GG with codim(GU,G)2(G\setminus U, G)\geq 2, we prove that (i) if GG is kk-isotropic, then UU satisfies strong approximation off any one (hence any finitely many) place; (ii) if GG is the spin group of a non-degenerate quadratic form which is non-compact over archimedean places, then UU satisfies strong approximation off all archimedean places. As a consequence, we prove that the same property holds for affine quadratic hypersurfaces. Our approach combines a fibration method with subgroup actions developed for induction on the codimension of GUG\setminus U, and an affine combinatorial sieve which allows to produce integral points with almost prime polynomial values

    Universality and correlations in individuals wandering through an online extremist space

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    The 'out of the blue' nature of recent terror attacks and the diversity of apparent motives, highlight the importance of understanding the online trajectories that individuals follow prior to developing high levels of extremist support. Here we show that the physics of stochastic walks, with and without temporal correlation, provides a unifying description of these online trajectories. Our unique dataset comprising all users of a global social media site, reveals universal characteristics in individuals' online lifetimes. Our accompanying theory generates analytical and numerical solutions that describe the characteristics shown by individuals that go on to develop high levels of extremist support, and those that do not. The existence of these temporal and also many-body correlations suggests that existing physics machinery can be used to quantify and perhaps mitigate the risk of future events

    Negative-GSP: An efficient method for mining negative sequential patterns

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    Different from traditional positive sequential pattern mining, negative sequential pattern mining considers both positive and negative relationships between items. Negative sequential pattern mining doesn't necessarily follow the Apriori principle, and the searching space is much larger than positive pattern mining. Giving definitions and some constraints of negative sequential patterns, this paper proposes a new method for mining negative sequential patterns, called Negative-GSP. Negative-GSP can find negative sequential patterns effectively and efficiently by joining and pruning, and extensive experimental results show the efficiency of the method. © 2009, Australian Computer Society, Inc

    The Performance of CRTNT Fluorescence Light Detector for Sub-EeV Cosmic Ray Observation

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    Cosmic Ray Tau Neutrino Telescopes (CRTNT) using for sub-EeV cosmic ray measurement is discussed. Performances of a stereoscope configuration with a tower of those telescopes plus two side-triggers are studied. This is done by using a detailed detector simulation driven by Corsika. Detector aperture as a function of shower energy above 10^17 eV is calculated. Event rate of about 20k per year for the second knee measurement is estimated. Event rate for cross calibration with detectors working on higher energy range is also estimated. Different configurations of the detectors are tried for optimization.Comment: 5 pages, 4 figures, submitted to HEP & N
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