1,720,961 research outputs found
Learning regular expressions from noisy sequences
No full textAbstract. The presence of long gaps dramatically increases the diffi-culty of detecting and characterizing complex events hidden in long se-quences. In order to cope with this problem, a learning algorithm based on an abstraction mechanism is proposed: it can infer the general model of complex events from a set of learning sequences. Events are described by means of regular expressions, and the abstraction mechanism is based on the substitution property of regular languages. The induction algo-rithm proceeds bottom-up, progressively coarsening the sequence granu-larity, letting correlations between subsequences, separated by long gaps, naturally emerge. Two abstraction operators are defined. The first one detects, and abstracts into non-terminal symbols, regular expressions not containing iterative constructs. The second one detects and abstracts it-erated subsequences. By interleaving the two operators, regular expres-sions in general form may be inferred. Both operators are based on string alignment algorithms taken from bio-informatics. A restricted form of the algorithm has already been outlined in previous papers, where the em-phasis was on applications. Here, the algorithm, in an extended version, is described and analyzed into details.
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
- …
