The source-item coverage of the exponential function

International audienceStatistical distributions in the production of information are most often studied in the framework of Lotkaian informetrics. In this article, we recall some results of basic theory of Lotkaian informetrics, then we transpose methods (Theorem1) applied to Lotkaian distributions by Leo Egghe (Theorem 2) to the exponential distributions (Theorem 3, Theorem 4). We give examples and compare the results (Theorem 5). Finally, we propose to widen the problem using the concept of exponential informetric process (Theorem 6).Les distributions statistiques dans le domaine de la production d'information sont le plus souvent étudiées dans le cadre de l'infométrie lotkaienne. Dans cet article, nous rappelons les résultats de base de la théorie lotkaienne, puis nous transposons les méthodes (théorème 1) appliquées aux distributions lotkaiennes par Leo Egghe (Théorème 2) aux distributions exponentielles (Théorème 3, Théorème 4). Nous donnons des exemples, puis nous élargissons le problème au concept de processus exponentiel infométrique (Théorème 6

Comparative analysis between impact factor and h-index for psychiatry journals

International audienceObjective: Journal Impact Factor (IF) is well known for being the document measure of scientific journal impact, despite several recognised limitations. Our study tried to propose a new rating system (journal h-index) applied to a sample of psychiatry journals and compared to IF. Method: In order to strictly compare their IF and h-index using the same data, we wanted to work on all the citations obtained in 2006 by the articles published in 2004-2005 in the 50 journals of our Web of Science sample of psychiatry. We studied the statistical correlation between the IF 2006 and h-index 2006. Results: The rankings of the 50 psychiatry journals were different when we took into account respectively the descending order of IF 2006 and h-index 2006 which revealed 16 steps and therefore 16 groups of journals. We noted that two journals were up 21 places (record) in h-index 2006 ranking and one journal lost 17 places. Nevertheless we obtained a high correlation coefficient well illustrated by the group of the seven first journals whose the two rankings were very close. We noted that our sample had only two journals really specialised in the publication of reviews. Conclusions: The rating of journals starting from the h-index may represent an interesting and complementary alternative to the well-known rating based on the IF. The h-index rating proposes a categorization of journals making it possible to create classes of journals with the same h-index. This type of ranking by classes is often appreciated and used by experts and scientific committees of evaluation

Comparative analysis between impact factor and h-index for pharmacology and psychiatry journals

International audienceUsing strictly the same parameters (identical two publication years (2004-2005) and identical one-year citation window (2006)), IF 2006 was compared with h-index 2006 for two samples of "Pharmacology and Pharmacy" and "Psychiatry" journals computed from the ISI Web of Science. For the two samples, the IF and the h-index rankings of the journals are very different. The correlation coefficient between the IF and the h-index is high for Psychiatry but lower for Pharmacology. The linearity test performed between the h-index and showed the great sensitivity of the model compared with . The IF and h-index can be completely complementary when evaluating journals of the same scientific discipline

Propagation de métadonnées par l'analyse des liens

http://www.emse.fr/~mbeig/PUBLIS/2003-jft-p257-prime.pdfInternational audienc

Clusterisation du Web en vue d'extraction de corpus homogènes

ISBN 2-906855-18-9Web resources are more and more different, not only regarding thematic content but also related to type of document, geographic origin, level, language, etc. However, web search engines do not take into account this heterogeneity and propose only a thematic access by keywords to the documents. This paper presents a method allowing to extract homogenous corpus of web documents. This method based on link analysis uses co-citation method and focuses more specially on the notion of type of web documents.Les ressources disponibles sur le Web sont de plus en plus diverses aussi bien d'un point de vue thématique, qu'au niveau de leur type, de leur origine géographique, etc. Cependant, les outils de recherche ne prennent pas en compte cette hétérogénéité et ne proposent qu'un accès par mots-clés aux documents du web. Cet article présente une méthode basée sur les hyperliens, permettant d'extraire du graphe Web des sous-corpus de documents homogènes. L'expérience décrite ici utilise la méthode des co-citations et s'intéresse plus spécialement à la notion de genre (type) de document web

Relationships between Consumption, Publication and Impact in French Universities in a value perspective: A Bibliometric Analysis

International audienceThe study aims to investigate the relationships between consumption of e-journals distributed by Elsevier ScienceDirect platform, publication (articles) and impact (citations) in a sample of 13 French universities, from 2003 to 2009. It adopts a value perspective as it questions whether or not publication activity and impact are some kind of return led by consumption. A bibliometric approach was used to explore the relations between these three variables. The analysis developed indicators inspired by the mathematical h-Index technique. Results show that the relation between consumption, publication and citations depends on the discipline’s profile, the intensity of research and the size of each institution. Moreover, although relations have been observed between the three variables, it is not possible to determine which variable comes first to explain the phenomena. The study concludes by showing strong correlations, which nevertheless do not lead to clear causal relations. The article provide practical implication for academic library managers who want to show the added value of their electronic e-journals collections can replicate the study approach. Also for policy makers who want to take into account e-journals usage as an informative tool to predict the importance of publication activity. Originality: The study is the first French contribution to e-journal value studies. Its originality consists in developing a value viewpoint that relies on a bibliometric approach.Keywords: scholarly journals, e-journals, ScienceDirect, value, academic libraries, downloads, citations, impact, articles, publication, research outcomes, h-index, France, bibliometry

On the relation between the maximum entropy Principle and the principle of Least effort : The continuous case

International audienceThe Maximum Entropy Principle (MEP) maximizes the entropy provided the effort remains constant. The Principle of Least effort (PLE) minimizes the effort provided the entropy remains constant. The paper investigates the relation between these two principles. In some kinds of effort functions, called admissible, it is shown that these two principles are equivalent. The results are illustrated by the size-frequency distribution met in infometry in Informatin Production Processes.e.Le principe d'Entropie maximum (MPE), maximise l'entropie en maintenant un effort constant. Le principe du moindre Effort (PLE) minimise l'effort en maintenant l'entropie constante. L'article étudie la relation entre ces deux principes. Pour des fonctions d'effort dites admissibles, on montre que les deux principes sont équivalents. Les résultats sont illustrés par des distributions rencontrées dans les processus de production d'information en infométri

Bibliométrie : esquisse d'un panorama

This paper builds up a panorama of different schools related to what is now called bibliometric or in-formetrics. We have distinguished between : distributional bibliometrics, evaluation of a documentary information system, bibliometrics on bibliographical references, bibliometrics and sociology. We study methods used in each field, with a special regard for the role played by statistics, and on the influence of the field of investigation concerned (libraries, data banks...) in the definition of their fundamental axes.Cet article fait un panorama des différentes écoles qui se rattachent à la bibliométrie et à l'infométrie. Nous les avons nommées : bibliométrie distributionnelle, évaluation d'un système d'information documentaire, bibliométrie des références bibliographiques, bibliométrie et sociologie. On étudie les méthodes utilisées par chacune d'elles. On s'attache plus particulièrement au rôle joué par les statistiques dans la définition de leur problématique ainsi que de l'influence du champ d'expérimentation observé (bibliothèques, banques de données...).Lafouge Thierry. Bibliométrie : esquisse d'un panorama. In: Sciences de la société, n°29, 1993. L'information stratégique. pp. 99-110