1,721,003 research outputs found
Proceedings of the fourteenth Italian Symposium on Advanced Database Systems (SEBD2006)
No full textPORTONOVO (ANCONA), SEBD 200
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
Micro-Raman on flax fibers: ageing fingerprints in spectra
No full textFlax fiber (Linum usitatissimum) is probably the earliest textile material and holds a great archaeological interest [1]. The possibility to define a connection between ageing and molecular characteristics is thus a concrete purpose aiming to help indirect dating. The flax fibers mainly consist of cellulose, hemicellulose, lignin and pectic material.
Vibrational spectroscopy, and in particular Raman spectroscopy, has been already used to give a non-destructive characterization of archaeological flax fabrics [2,3]. While larger acquisition areas and IR excitation (exc = 1064 nm) were used in [3], in the present work micro-Raman spectroscopy and visible-excited fluorescence spectroscopy were applied to 24 micrometric-sized fibers from historical linen (dating from about 3000 B.C. to the XVII cent.) and 12 crude or treated modern fibers. Micro-Raman and micro-fluorescence spectra were acquired respectively by means of a JASCO NRS-5000 Raman system (exc = 785 nm) and of a JASCO RMP-100 microprobe coupled with a Lot Oriel MS25 spectrometer and with a frequency-doubled Nd:YAG laser (exc = 532 nm).
In the examined spectral range, from 70 cm-1 to 2600 cm-1, the ratio between 1121 cm-1 and 1096 cm-1 bands has been proved to be a possible signature of ageing [4,5]. Evaluating the above-mentioned band ratio (I1121 cm-1/ I1096 cm-1) after baseline correction, micro-Raman spectra show that modern samples exhibit a quite constant ratio value of 0.85±0.05, which diminishes (up to 0.7) if the linen fiber is heated or bleached. Fibers form archaeological linen show a reduced value for the ratio, that decreases to about 0.5 depending on the age and on the conservation conditions. It should be emphasized that for the most ancient samples or the most severely aged modern samples, the above ratio could not be determined due to the high fluorescence background overlapping the Raman signals.
As the possible presence of non-cellulosic carbohydrates in the linen fiber can produce a different spectral pattern, especially in the 280-600 cm-1 region, with variations of relative signal intensities, multiple spectra relative to the same fibers must be acquired, selected and averaged, thus reducing also the possible contribution of extraneous material.
A Pearson correlation value of about 0.7 between the intensity of the fiber fluorescence emission and the age of the flax samples is also obtained, showing variations mainly due to the possible influence of other features such as contamination from organic substances (balms, dyes etc.).
In conclusion, this study opens a perspective on the possibility of a truly micro-destructive investigation of ancient textiles, exploiting the molecular specificity of spectroscopic techniques.
[1] E.J.W. Barber, Prehistoric Textiles, Princeton University Press, Princeton, NY, USA, 1991, p.12
[2] H. G.M. Edwards, D. W. Farwell, D. Webster, Spectrochemica Acta A, 53, 1997, 2383.
[3] G. Fanti, P. Baraldi, R. Basso, A. Tinti, Vibrational Spectroscopy 67, 2013, 61.
[4] H. G.M. Edwards, N. F. Nikhassan, D. W. Farwell, P. Garside, P. Wyeth, J. Raman Spectrosc. 37, 2006, 1193.
[5] A. Jahan, M.W. Schröder, M. Füting, K. Schenzel, W. Diepenbrock, Spectrochemica Acta A, 58, 2002, 2271
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
Relational data base design for the intensional aspects of a knowledge base
No full textPERGAMON PRES
On taxonomic reasoning in E/R environment
No full textin C. Batini, (a cura di) Entity-Relationship Approach, Elsevier Science Publishers B.V
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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