1,721,583 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
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
Dual-phase steel rebars for high-ductile r.c. structures, Part 1: Microstructural and mechanical characterization of steel rebars
No full textThe considerable influence of steel's mechanical behaviour on the dissipative capacity of r.c. structures has led to increasing interest in optimizing the mechanical properties of the reinforcing bars used for seismic applications.
The work presented herein is part of a broad-ranging study on the potential utilization of highly innovative types of steel for reinforced concrete earthquake-resistant structures. In particular, we present the main results obtained in experimental trials on a low-C, Mn-Si steel in the form of concrete reinforcing bars subjected to intercritical tempering treatment in a temperature range between 740 and 820 degrees C to obtain various dual-phase ferrite-martensite structures. The samples were characterized via mechanical tests and metallographic analyses in order to correlate the bars' characteristics with the microstructure of the steel itself.
Experimental characterization of this steel has allowed for the development of a mathematical model to enable the evaluation of the ductility performance of concrete structural elements reinforced with dual-phase steel bars
A broadband W-band polarization rotator with very low cross polarization
No full textWe present a 82100 GHz circular waveguide polarization rotator based on a broadband rotating half-wave retarder. The device was designed for astrophysics experiments aimed to characterize the polarization of the cosmic microwave background radiation. The device is based on a Pancharatnam recipe used in optics and has a very low intrinsic cross polarization, very flat phase response across the band and very low losses. It can be used in astronomical experiments where very high performance is required but also as a variable polarization source for instrument calibrations. The design was manufactured and then tested using a millimeter-wave vector network analyzer. The average measured RL, IL and cross polarization across a 30% bandwidth were, respectively, -38 dB, -0.27 dB, and -36.5 dB. © 2010 IEEE
W-band planar antennas for next generation sub-millimeter focal plane arrays
No full textCurrent and future generations of astronomical instruments in the millimetre (mm) and sub-mm range are in need of increased sensitivity through the use of ever larger focal planes with 1000s of pixels. Mass, dimensions and manufacture requirements, mainly for new space missions, is driving the technology to go from feedhorn, and generally waveguide based cold optics to planar coupled detectors, while maintaining RF performance. The present results of a current ESA TRP are presented with respect to the work on planar antennae that will be coupled to cold bolometric detectors through the use of planar mesh lenses. Two planar antennae operating at W-band are developed, namely, a broadband sinuous antenna and a variation on the classical dual-slot antenna to realise multi-band functionality
Dielectrically embedded mesh half wave plate beam impact studies
No full textAn alternative solution to classic birefringent Half Wave Plates (HWP), based on the photolithographic techniques, has been recently developed. This new device can offer a very good alternative as a polarisation modulator for future CMB polarisation instruments. However, the systematic effects that this HWP will introduce in the overall instrument need to be investigated. We present a preliminary study of the impact of this dielectrically embedded HWP on the beam shape of a corrugated horn and its performance across the beam. Using a W-band Vector Network Analyser, we measured the co- and cross-polarisation beams of the HWP-horn system and the differential phase-shift introduced by the HWP across the beam. © 2012 SPIE
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