1,720,957 research outputs found
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
Bias-free giant tunability of microwave properties in multilayer rhomboid nanomagnets
No full textReprogrammable microwave properties based on magnetic nanostructures are of great interest for future information-processing technologies in the GHz frequency range. Tunable microwave properties are typically obtained by varying the bias magnetic field, which, however, hinders the device integration capability at the nanoscale. Here, we show a route for bias-field-free giant tunability of microwave properties based on isolated and dipolar coupled networks of multilayer rhomboid nanomagnets. A comprehensive investigation of multilayers beyond trilayer and various complex networks of them are carried out using micromagnetic simulations. The giant tunability of the microwave properties has been attributed to the strong dipolar field variations associated with different remanent states which can be reconfigured with a nanosecond pulse field. We have also presented an approach for realization of an artificial 3D antiferromagnetic crystal. These results have potential applications in fast reprogrammable and energy-efficient microwave devices which operate without any bias magnetic field
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
Reconfigurable microwave properties of zigzag magnetic nanowires
No full textReconfigurable microwave devices which operate without any external bias magnetic field are of great importance for monolithic device integration of microwave components. Magnetic nanostructures and arrays are found to be promising due to the ease of their control parameters. However, use of a bias magnetic field for tunable microwave operation hinders the advantage of nanomagnets. Here, we propose a novel method for reconfigurable microwave operation based on zigzag nanowires which do not require any external bias magnetic field. Tunable microwave operation relies on reconfigurable remanent magnetic states which are associated with distinct magnetization dynamic responses. Owing to two different domain configurations for different remanent magnetic states, variation of internal magnetic fields governs the observed tunability of microwave operating frequency. In addition, microwave properties are highly sensitive to the zigzag angle which offers additional functionality along with bias-field-free operation. © 2020 IOP Publishing Ltd
Reconfigurable microwave properties in C-, L- and S-shaped nanomagnets
No full textDynamic responses of magnetic nanostructures exist in the GHz frequency range and therefore offer excellent opportunities to miniaturize microwave devices. Here, we have demonstrated C-, L- and S-shaped nanomagnetic structures which enable reconfigurable microwave properties. Magnetic and microwave properties have been studied utilizing micromagnetic simulations. We have obtained two different magnetic remanent states for all the samples by using a simple field initialization process. Different remanent states are associated with distinct magnetization dynamic properties which can be tuned using a magnetic field pulse of nanosecond width. Remarkably large frequency shifts have been observed between the two different magnetic remanent states. Tunable microwave properties relies on the strong dipolar field variations - the effect of which have been shown systematically in all spatial directions in strategically designed sample geometries such as single layer arrays, isolated multilayers and networks of multilayers. The results have potential implications for the realization of ultra-low-power and ultrafast microwave devices
Reconfigurable microwave properties in trapezoid-shaped nanomagnets without bias magnetic field
No full textSelf-biased nanomagnetic structures with reconfigurable microwave properties are going to play a key role in the miniaturization of microwave devices. However, examples of such nanomagnets are very few. Here, we present a new nanostructure based on trapezoid shape which possesses two different remanent states through a simple sub-ns field initialization process. Different remanent states are associated with distinct microwave properties with a remarkably large shift between their microwave spectra. Other possible sample schemes based on networks, multilayers and arrays of trapezoid nanomagnets have also been discussed for a comprehensive report on this novel design architecture. The underlying physics of tunable microwave properties has been explained analytically using dipolar field driven variation of total effective field landscapes for different remanent states. The results offer a new route for the realization of the on-chip integration of microwave devices without any requirement of a bias magnetic field
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