1,720,994 research outputs found
Impulsive sources localisation in noisy environment using modified beamforming method
No full textWhen a machine has faults in its rotating part, it normally generates periodic vibration or acoustic signals. These signals are often periodic but impulsive. This paper addresses the way in which we can find where the impulsive sources are. We propose a signal processing method that can identify impulsive sources' location. The method is robust with respect to noise; spatially distributed noise. Numerical simulation and experiments are performed to verify the method. Results show that the proposed technique is quite powerful for localising the sources in noisy environments. The method also required less microphones than conventional beamforming method. (c) 2005 Elsevier Ltd. All rights reserved
Understanding structures and electronic/spintronic properties of single molecules, nanowires, nanotubes, and nanoribbons towards the design of nanodevices
No full textTheoretical understanding of metal nanowires and molecular devices is described towards the design of novel nanodevices. We focus our attention on structures, electronic, and spintronic properties of low dimensional metallic/molecular nanostructures based mostly on our recent works. The discussion includes (i) electric field induced molecular orbital control towards molecular electronic and spintronic devices, (ii) conductances of carbon nanotubes and graphene nanoribbons, (iii) low dimensional structures and properties, focusing on the stability, quantum conductance, and magnetic features of metallic nanowires, and (iv) metal vs. carbon nanotube/graphene electrodes for negative differential resistance in molecular electronics
Neutral and Anionic Gold Decamers: Planar Structure with Unusual Spatial Charge-Spin Separation
No full textWe have investigated the issue of two-dimensional (2D) versus three-dimensional (3D) structures for neutral-state Au(10) and clarified the lowest-energy structure among a few 2D Au(10)(-) isomers. Though almost all previous works were based on density functional theory (DFT), we here carried out not only extensive DFT calculations but also high levels of ab initio calculations of Moller-Plesset second order perturbation theory (MP2), and coupled cluster theory with single and double excitations (CCSD) including perturbative triple excitations [CCSD(T)]. While DFT favors 2D structures, MP2 and CCSD(T) favor 3D structures for moderate-sized basis sets. However, we note that the basis-set superposition error (BSSE) corrections make the ab intio results favor 2D structures too. The near-degeneracy (driven by relativistic effects) of 5d and 6s orbitals of gold helps stabilize acute apex gold atoms, resulting in 2D structures. The planar triangular structures of a local minimum Au(10) (triplet) and the global minimum Au(10)(-) show remarkable spatial charge-spin separation due to their singly occupied molecular orbital(s). By the same reason, Au(10)(-) shows much larger vertical detachment energy than other even-numbered gold cluster anions
Activation volumes of wall-motion and nucleation processes in Co-based ferromagnetic multilayer films
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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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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