1,725,867 research outputs found
Alternate title: Si Si Si Si Senor!
No full textFirst Line: In old Barcelona, I met sweet RomonaFirst Line of Chorus:I wonder why she kept on saying, "si si si si senor"Title of Larger Work: SinbadKey: A Mino
Energy and system size dependence of chemical freeze-out in relativistic nuclear collisions
No full textWe present a detailed study of chemical freeze-out in p-p, C-C, Si-Si and Pb-Pb collisions at beam momenta of 158A GeV as well as Pb-Pb collisions at beam momenta of 20A, 30A, 40A and 80A GeV. By analyzing hadronic multiplicities within the statistical hadronization model, we have studied the parameters of the source as a function of the number of the participating nucleons and the beam energy. We observe a nice smooth behaviour of temperature, baryon chemical potential and strangeness under-saturation parameter as a function of energy and nucleus size. Interpolating formulas are provided which allow to predict the chemical freeze-out parameters in central collisions at centre-of-mass energies > 4.5 GeV and for any colliding ions. Specific discrepancies between data and model emerge in particle ratios in Pb-Pb collisions at SPS between 20A and 40A GeV of beam energy which cannot be accounted for in the considered model schemes
Multi-scale spectral decomposition of massive graphs
No full textComputing the k dominant eigenvalues and eigenvectors of massive graphs is a key operation in numerous machine learning applications; however, popular solvers suffer from slow convergence, especially when k is reasonably large. In this paper, we propose and analyze a novel multi-scale spectral decomposition method (MSEIGS), which first clusters the graph into smaller clusters whose spectral decomposition can be computed efficiently and independently. We show theoretically as well as empirically that the union of all cluster's subspaces has significant overlap with the dominant subspace of the original graph, provided that the graph is clustered appropriately. Thus, eigenvectors of the clusters serve as good initializations to a block Lanczos algorithm that is used to compute spectral decomposition of the original graph. We further use hierarchical clustering to speed up the computation and adopt a fast early termination strategy to compute quality approximations. Our method outperforms widely used solvers in terms of convergence speed and approximation quality. Furthermore, our method is naturally parallelizable and exhibits significant speedups in shared-memory parallel settings. For example, on a graph with more than 82 million nodes and 3.6 billion edges, MSEIGS takes less than 3 hours on a single-core machine while Randomized SVD takes more than 6 hours, to obtain a similar approximation of the top-50 eigenvectors. Using 16 cores, we can reduce this time to less than 40 minutes
Multi-scale link prediction
Full text linkThe automated analysis of social networks has become an important problem due to the pro-liferation of social networks, such as LiveJournal, Flickr and Facebook. The scale of these social networks is massive and continues to grow rapidly. An important problem in social network analysis is proximity estimation that infers the closeness of different users. Link prediction, in turn, is an important application of proximity estimation. However, many methods for com-puting proximity measures have high computational complexity and are thus prohibitive for large-scale link prediction problems. One way to address this problem is to estimate proximity measures via low-rank approximation. However, a single low-rank approximation may not be sufficient to represent the behavior of the entire network. In this paper, we propose Multi-Scale Link Prediction (MSLP), a framework for link prediction, which can handle massive networks. The basis idea of MSLP is to construct low rank approximations of the network at multiple scales in an efficient manner. Based on this approach, MSLP combines predictions at multiple scales to make robust and accurate predictions. Experimental results on real-life datasets with more than a million nodes show the superior performance and scalability of our method.
Electroluminescence from Si/Si oxynitride superlattices
No full textThe Si/Si oxynitride superlattices, with three periods, have been grown using the two-target alternation magnetron sputtering technique. The thicknesses of Si oxynitride layers and Si layers in the superlattices are 2.0 and 1.4 nm, respectively. Visible electroluminescence (EL) from a semitransparent Au film/(Si/Si oxynitride) superlattice/p-Si structure has been observed. Each EL spectrum of the structure has a dominant peak around 640 nm, a weaker peak around 520 nm, and a shoulder around 820 nm. By comparing the EL from the semitransparent Au film/(Si/Si oxynitride) superlattice/p-Si structure with that from a semitransparent Au film/Si oxynitride film/ p-Si structure, we found that the EL efficiency of the former structure is about 2-4 times of that of the latter one. (C) 1998 American Institute of Physics.Physics, AppliedSCI(E)EI0ARTICLE263408-34107
From classical to quantum quadratic cost control
Full text linkControlling the size of the solution of a (deterministic, stochastic or quantum stochastic) differential equation, by minimizing an appropriate cost functional, is very important in classical and quantum engineering. Of particular importance is the case of linear differential equations and quadratic cost functionals, since in that case the control processes can be explicitly calculated. In this paper we review some basic aspects of the classical theory and we present our results in the quantum case, obtained over the past few years
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Si/Si直接键合界面性质的研究
No full text通过三步直接键合方法实现了Si/Si键合.采用XPS、FTIR、I-V、拉伸强度等手段对Si/Si键合结构的界面特性作了深入广泛的研究.研究结果表明,高温退火后,在键合界面没有Si-H和Si-OH网络存在,键合界面主要由单质Si和不定形氧化硅SiOx组成.同时,研究还表明,I-V特性和键合强度强烈地依赖于退火温度
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