1,721,081 research outputs found
A novel highly selective and tunable optical bandpass filter using a fibre grating and a fibre Fabry-Perot
No full textWe present a novel continuously tunable optical bandpass filter composed of a FFP, on an optical circulator, and a fiber grating. The structure combines the high selectivity of the FFT and the bandpass nature of the fiber grating
WDM grid tunable filter based on a sampled fibre grating and a FFP
No full textWe propose and report on a novel device based on the cascade of a sampled fibre grating and a fibre Fabry-Perot. The operation and experimental demonstration of the combined structure are presented showing stability and tunability advantages for filtering and channel routing applications in WDM telecommunication systems using normalised frequency grids, such as that proposed by the ITU
Full characterization of long periodic superstructure fibre Bragg gratings in multichannel devices
No full textThe characterization of the amplitude and delay response of superstructure fiber Bragg gratings was discussed. The periodic superstructure fiber Bragg gratings are characterized by a periodic variation of the grating parameters resulting in a multiband spectra response arising from every Fourier component of the superstructure. The modeling of the superstructure using the coupling-mode theory and the Runge-Kutta method for solving Riccati equations is discussed
Experimental demonstration of an ultraselective and tunable optical bandpass filter using a fibre grating and a Fabry-Perot
No full textThe authors report on the use of a structure composed of a fibre Fabry-Perot and a fibre grating as an ultraselective and tunable optical bandpass filter. The first experimental demonstration of the filter operation is presented and a range of tuning of several hundreds of gigahertz can be achieved by using the presented techniques
Full low-cost characterization of long periodic superstructure fiber Bragg gratings
No full textIn this letter, we experimentally demonstrate that the low-cost characterization of the amplitude and delay response of sampled gratings is possible using the Hilbert transform method
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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