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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Cross-Layer Joint Optimization of FEC Channel Codes and Multiple Description Coding for Video Delivery over IEEE 802.11e Links
No full textThis paper presents two cross-layer optimisation strategies based on the IEEE 802.11e standard that enable a robust video transmission using adaptively Forward Error Correction channel codes at transport layer and a Multiple Description Coding architecture. The first approach classifies the characteristics of the sequence to be coded, while the second relies on a parametric model of the distortion which is estimated during the coding operations. The performances of these schemes are then improved by a packet classification strategy. Experimental results show that both cross-layer optimisation algorithms perform well with a small computational effort but different playout delays
Rate allocation for robust video streaming based on distributed video coding
No full textThis paper proposes an error resilient coding scheme that employs distributed video
coding tools. A bitstream, produced by any standard motion-compensated predictive
codec (MPEG-x, H.26x), is sent over an error-prone channel. In addition, a Wyner–Ziv
encoded auxiliary bitstream is sent as redundant information to serve as a forward error
correction code. At the decoder side, error concealed reconstructed frames are used as
side information by the Wyner–Ziv decoder, and the corrected frame is used as a
reference by future frames, thus reducing drift. We explicitly target the problem of rate
allocation at the encoder side, by estimating the channel induced distortion in the
transform domain. Rate adaptivity is achieved at the frame, subband and bitplane
granularity. Experimental results conducted over a simulated error-prone channel reveal
that the proposed scheme has comparable or better performance than a scheme where
forward error correction codes are used. Moreover the proposed solution shows good
performance when compared to a scheme that uses the intra-macroblock refresh
procedure
Variations on the Author
Get PDF“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
Get PDFWe 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
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