51 research outputs found

    Updated tests of scaling and universality for the spin-spin correlations in the 2D and 3D spin-S Ising models using high-temperature expansions

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    We have extended, from order 12 through order 25, the high-temperature series expansions (in zero magnetic field) for the spin-spin correlations of the spin-S Ising models on the square, simple-cubic and body-centered-cubic lattices. On the basis of this large set of data, we confirm accurately the validity of the scaling and universality hypotheses by resuming several tests which involve the correlation function, its moments and the exponential or the second-moment correlation-lengths.Comment: 21 pages, 8 figure

    Sequential design of computer experiments for the estimation of a probability of failure

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    This paper deals with the problem of estimating the volume of the excursion set of a function f:RdRf:\mathbb{R}^d \to \mathbb{R} above a given threshold, under a probability measure on Rd\mathbb{R}^d that is assumed to be known. In the industrial world, this corresponds to the problem of estimating a probability of failure of a system. When only an expensive-to-simulate model of the system is available, the budget for simulations is usually severely limited and therefore classical Monte Carlo methods ought to be avoided. One of the main contributions of this article is to derive SUR (stepwise uncertainty reduction) strategies from a Bayesian-theoretic formulation of the problem of estimating a probability of failure. These sequential strategies use a Gaussian process model of ff and aim at performing evaluations of ff as efficiently as possible to infer the value of the probability of failure. We compare these strategies to other strategies also based on a Gaussian process model for estimating a probability of failure.Comment: This is an author-generated postprint version. The published version is available at http://www.springerlink.co

    Two-pion Bose-Einstein correlations in central Pb-Pb collisions at sNN\sqrt{s_{\rm NN}} = 2.76 TeV

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    The first measurement of two-pion Bose-Einstein correlations in central Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}} = 2.76 TeV at the Large Hadron Collider is presented. We observe a growing trend with energy now not only for the longitudinal and the outward but also for the sideward pion source radius. The pion homogeneity volume and the decoupling time are significantly larger than those measured at RHIC.Comment: 17 pages, 5 captioned figures, 1 table, authors from page 12, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/388

    Suppression of charged particle production at large transverse momentum in central Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}} = 2.76 TeV

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    Inclusive transverse momentum spectra of primary charged particles in Pb-Pb collisions at sNN\sqrt{s_{_{\rm NN}}} = 2.76 TeV have been measured by the ALICE Collaboration at the LHC. The data are presented for central and peripheral collisions, corresponding to 0-5% and 70-80% of the hadronic Pb-Pb cross section. The measured charged particle spectra in η<0.8|\eta|<0.8 and 0.3<pT<200.3 < p_T < 20 GeV/cc are compared to the expectation in pp collisions at the same sNN\sqrt{s_{\rm NN}}, scaled by the number of underlying nucleon-nucleon collisions. The comparison is expressed in terms of the nuclear modification factor RAAR_{\rm AA}. The result indicates only weak medium effects (RAAR_{\rm AA} \approx 0.7) in peripheral collisions. In central collisions, RAAR_{\rm AA} reaches a minimum of about 0.14 at pT=6p_{\rm T}=6-7GeV/cc and increases significantly at larger pTp_{\rm T}. The measured suppression of high-pTp_{\rm T} particles is stronger than that observed at lower collision energies, indicating that a very dense medium is formed in central Pb-Pb collisions at the LHC.Comment: 15 pages, 5 captioned figures, 3 tables, authors from page 10, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/98

    Music, working memory and reading

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    This study examined the impact of music and working memory on the reading of irregular words and pseudowords. Twenty-three advanced adult musicians and 45 undergraduate controls were tested on various musical abilities, verbal and spatial memory, and on the reading of irergular words and pseudowords. Results showed that when taking into account general education, advanced musicians performed better than the undergraduate controls on melodic organization, temporal perception and incidental music memory. They had better verbal memory, and were more accurate in reading irregular words but not pseudowords. Likewise, melodic organization and incidental incidental music memory correlated positively with the reading of two types of words but the effect attenuated once partiallng out general educaiton. Advanced musicians may be more fluent in processing overall pattern when reading music and therefore, are more capable of tranfering this skill to word reading. The results are consistent with previous studies in that music training improves children's reading ability and pitch discrimination. The results also implied the basic hierarchiical processing for music and speech recruits distinct cortical networks. Althgouh music training seems to benefit language learning more at a young age, language skills can be improved by some other means

    Improving Chinese Storing Text Retrieval Systems&apos; Security via a Novel Maximal Prefix Coding

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    As we have seen that Huffman coding has been widely used in data, image, and video compression. In this paper novel maximal prefix coding is introduced. Relationship between the Huffman coding and the optimal maximal prefix coding are discussed. We show that all Huffman coding schemes are optimal maximal prefix coding schemes and that conversely the optimal maximal prefix coding schemes need not to be the Huffman coding schemes. Moreover, it is proven that, for any maximal prefix code C, there exists an information source I = (, P) such that C is exactly a Huffman code for I. Therefore, it is essential to show that the class of Huffman codes is coincident with one of maximal prefix codes. A case study of data compression is also given. Comparing the Huffman coding, the maximal prefix coding is used for not only statistical modeling but also dictionary methods. And it is good at applying to a large information retrieval system and improving its security
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