1,721,199 research outputs found
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
Measuring and Improving Comparable Corpus Quality
No full textLes corpus bilingues sont des ressources essentielles pour s'affranchir de la barrière de la langue en traitement automatique des langues (TAL) dans un contexte multilingue. La plupart des travaux actuels utilisent des corpus parallèles qui sont surtout disponibles pour des langues majeurs et pour des domaines spécifiques. Les corpus comparables, qui rassemblent des textes comportant des informations corrélées, sont cependant moins coûteux à obtenir en grande quantité. Plusieurs travaux antérieurs ont montré que l'utilisation des corpus comparables est bénéfique à différentes taches en TAL. En parallèle à ces travaux, nous proposons dans cette thèse d'améliorer la qualité des corpus comparables dans le but d'améliorer les performances des applications qui les exploitent. L'idée est avantageuse puisqu'elle peut être utilisée avec n'importe quelle méthode existante reposant sur des corpus comparables. Nous discuterons en premier la notion de comparabilité inspirée des expériences d'utilisation des corpus bilingues. Cette notion motive plusieurs implémentations de la mesure de comparabilité dans un cadre probabiliste, ainsi qu'une méthodologie pour évaluer la capacité des mesures de comparabilité à capturer un haut niveau de comparabilité. Les mesures de comparabilité sont aussi examinées en termes de robustesse aux changements des entrées du dictionnaire. Les expériences montrent qu'une mesure symétrique s'appuyant sur l'entrelacement du vocabulaire peut être corrélée avec un haut niveau de comparabilité et est robuste aux changements des entrées du dictionnaire. En s'appuyant sur cette mesure de comparabilité, deux méthodes nommées: greedy approach et clustering approach, sont alors développées afin d'améliorer la qualité d'un corpus comparable donnée. L'idée générale de ces deux méthodes est de choisir une sous partie du corpus original qui soit de haute qualité, et d'enrichir la sous-partie de qualité moindre avec des ressources externes. Les expériences montrent que l'on peut améliorer avec ces deux méthodes la qualité en termes de score de comparabilité d'un corpus comparable donnée, avec la méthode clustering approach qui est plus efficace que la method greedy approach. Le corpus comparable ainsi obtenu, permet d'augmenter la qualité des lexiques bilingues en utilisant l'algorithme d'extraction standard. Enfin, nous nous penchons sur la tâche d'extraction d'information interlingue (Cross-Language Information Retrieval, CLIR) et l'application des corpus comparables à cette tâche. Nous développons de nouveaux modèles CLIR en étendant les récents modèles proposés en recherche d'information monolingue. Le modèle CLIR montre de meilleurs performances globales. Les lexiques bilingues extraits à partir des corpus comparables sont alors combinés avec le dictionnaire bilingue existant, est utilisé dans les expériences CLIR, ce qui induit une amélioration significative des systèmes CLIR.Bilingual corpora are an essential resource used to cross the language barrier in multilingual Natural Language Processing (NLP) tasks. Most of the current work makes use of parallel corpora that are mainly available for major languages and constrained areas. Comparable corpora, text collections comprised of documents covering overlapping information, are however less expensive to obtain in high volume. Previous work has shown that using comparable corpora is beneficent for several NLP tasks. Apart from those studies, we will try in this thesis to improve the quality of comparable corpora so as to improve the performance of applications exploiting them. The idea is advantageous since it can work with any existing method making use of comparable corpora. We first discuss in the thesis the notion of comparability inspired from the usage experience of bilingual corpora. The notion motivates several implementations of the comparability measure under the probabilistic framework, as well as a methodology to evaluate the ability of comparability measures to capture gold-standard comparability levels. The comparability measures are also examined in terms of robustness to dictionary changes. The experiments show that a symmetric measure relying on vocabulary overlapping can correlate very well with gold-standard comparability levels and is robust to dictionary changes. Based on the comparability measure, two methods, namely the greedy approach and the clustering approach, are then developed to improve the quality of any given comparable corpus. The general idea of these two methods is to choose the highquality subpart from the original corpus and to enrich the low-quality subpart with external resources. The experiments show that one can improve the quality, in terms of comparability scores, of the given comparable corpus by these two methods, with the clustering approach being more efficient than the greedy approach. The enhanced comparable corpus further results in better bilingual lexicons extracted with the standard extraction algorithm. Lastly, we investigate the task of Cross-Language Information Retrieval (CLIR) and the application of comparable corpora in CLIR. We develop novel CLIR models extending the recently proposed information-based models in monolingual IR. The information-based CLIR model is shown to give the best performance overall. Bilingual lexicons extracted from comparable corpora are then combined with the existing bilingual dictionary and used in CLIR experiments, which results in significant improvement of the CLIR system
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
Uncertainty in a precision oriented information retrieval system.
No full textInternational audienceno abstrac
X-IOTA : An open XML framework for IR experimentation. Application on multiple weighing scheme tests in a bilingual corpus
No full textInternational audienceCarrying out experiments in Information Retrieval is a heavy activity requiring fast tools to treat collections of significant size, and at the same time flexible tools to leave the most possible freedom during the experimentation. System X-IOTA was developed to answer the criterion of flexibility and thus to support fast installation of various experiments using automatic natural language treatments. The architecture is designed to allow a distribution of computations among distributed servers. We use this framework to test different set of weighting particularly the new Derivation from Randomness against Okapi
Technical aspects of Thesaurus Construction in TIPS
No full textThis paper describes the work done in the TIPS project about the construction of a thesaurus. This construction is a merge from a compilation of data from several web sources. These data comes from manual work, some data are real thesaurus, other are indexing recommendations. The merge is done with automatically extracted terms from large text corpora. The automatic extraction is based on both syntax and statistics. We present in this paper the way thesaurus are built and the results on Scientific corpus in the context of the TIPS project. This short paper emphasis on some technical aspects
Traitement de la langue pour l'extraction de connaissances pour la recherche d'information
No full textN/Ano abstrac
Building Thesaurus from Manual Sources and Automatic Scanned Texts
No full textInternational audienceThis paper describes the work done in the TIPS project about the construction of a thesaurus base. This construction is a merge from a thesaurus manually built and one automatically extracted from large text corpora. Several manually built thesaurus have been semi-formatted to be merged in a consistent common base. The automatic extraction is based on both syntax and statistics. We present in this paper the way thesaurus are built and the results on Scientific corpus in the context of the TIPS project
- …
