Literatur zur Informationserschließung
Diese Datenbank enthält über 40.000 Dokumente zu Themen aus den Bereichen Formalerschließung – Inhaltserschließung – Information Retrieval.
© 2015 W. Gödert, TH Köln, Institut für Informationswissenschaft
/
Powered by litecat, BIS Oldenburg
(Stand: 04. Juni 2021)
Suche
Suchergebnisse
Treffer 1–20 von 60
sortiert nach:

1Rousseau, R. ; Egghe, L. ; Guns, R.: Becoming metricwise : a bibliometric guide for researchers.
Cambridge, MA : Elsevier, Chandos Publishing, 2018. xv, 385 S.
ISBN 9780081024744
Abstract: Aims to inform researchers about metrics so that they become aware of the evaluative techniques being applied to their scientific output. Understanding these concepts will help them during their funding initiatives, and in hiring and tenure. The book not only describes what indicators do (or are designed to do, which is not always the same thing), but also gives precise mathematical formulae so that indicators can be properly understood and evaluated. Metrics have become a critical issue in science, with widespread international discussion taking place on the subject across scientific journals and organizations. As researchers should know the publicationcitation context, the mathematical formulae of indicators being used by evaluating committees and their consequences, and how such indicators might be misused, this book provides an ideal tome on the topic. Provides researchers with a detailed understanding of bibliometric indicators and their applications. Empowers researchers looking to understand the indicators relevant to their work and careers. Presents an informed and rounded picture of bibliometrics, including the strengths and shortcomings of particular indicators. Supplies the mathematics behind bibliometric indicators so they can be properly understood. Written by authors with longstanding expertise who are considered global leaders in the field of bibliometrics
Anmerkung: Rez. in: JASIST 70(2019) no.5, S.530532 (I. Dorsch)
Themenfeld: Informetrie
LCSH: Bibliometrics ; Electronic books
RSWK: Bibliometrie / Wissenschaft / Veröffentlichung
BK: 02.13 (Wissenschaftspraxis)
DDC: 020.21 / dc23
GHBS: AZC (E)
LCC: Z669.8
RVK: AK 28100 ; AN 96300 ; AN 96400

2Egghe, L.: Informetric explanation of some Leiden Ranking graphs.
In: Journal of the Association for Information Science and Technology. 65(2014) no.4, S.737741.
Abstract: The Sshaped functional relation between the mean citation score and the proportion of top 10% publications for the 500 Leiden Ranking universities is explained using results of the shifted Lotka function. Also the concave or convex relation between the proportion of top 100?% publications, for different fractions ?, is explained using the obtained new informetric model.
Themenfeld: Informetrie

3Egghe, L.: ¬A good normalized impact and concentration measure.
In: Journal of the Association for Information Science and Technology. 65(2014) no.10, S.20522054.
(Brief communication)
Abstract: It is shown that a normalized version of the gindex is a good normalized impact and concentration measure. A proposal for such a measure by Bartolucci is improved.
Themenfeld: Informetrie
Objekt: gindex

4Egghe, L.: Theory of the topical coverage of multiple databases.
In: Journal of the American Society for Information Science and Technology. 64(2013) no.1, S.126131.
Abstract: We present a model that describes which fraction of the literature on a certain topic we will find when we use n (n = 1, 2, .) databases. It is a generalization of the theory of discovering usability problems. We prove that, in all practical cases, this fraction is a concave function of n, the number of used databases, thereby explaining some graphs that exist in the literature. We also study limiting features of this fraction for n very high and we characterize the case that we find all literature on a certain topic for n high enough.
Themenfeld: Informetrie

5Egghe, L.: Note on a possible decomposition of the hIndex.
In: Journal of the American Society for Information Science and Technology. 64(2013) no.4, S.871.
(Letter to the editor)
Themenfeld: Informetrie
Objekt: hindex

6Egghe, L. ; Bornmann, L.: Fallout and miss in journal peer review.
In: Journal of documentation. 69(2013) no.3, S.411416.
Abstract: Purpose  The authors exploit the analogy between journal peer review and information retrieval in order to quantify some imperfections of journal peer review. Design/methodology/approach  The authors define fallout rate and missing rate in order to describe quantitatively the weak papers that were accepted and the strong papers that were missed, respectively. To assess the quality of manuscripts the authors use bibliometric measures. Findings  Fallout rate and missing rate are put in relation with the hitting rate and success rate. Conclusions are drawn on what fraction of weak papers will be accepted in order to have a certain fraction of strong accepted papers. Originality/value  The paper illustrates that these curves are new in peer review research when interpreted in the information retrieval terminology.

7Egghe, L. ; Guns, R. ; Rousseau, R. ; Leuven, K.U.: Erratum.
In: Journal of the American Society for Information Science and Technology. 63(2012) no.2, S.429.
(Erratum)
Anmerkung: This article corrects: Thoughts on uncitedness: Nobel laureates and Fields medalists as case studies in: JASIST 62(2011) no,8, S.16371644.

8Egghe, L. ; Rousseau, R.: ¬The Hirsch index of a shifted Lotka function and its relation with the impact factor.
In: Journal of the American Society for Information Science and Technology. 63(2012) no.5, S.10481053.
Abstract: Based on earlier results about the shifted Lotka function, we prove an implicit functional relation between the Hirsch index (hindex) and the total number of sources (T). It is shown that the corresponding function, h(T), is concavely increasing. Next, we construct an implicit relation between the hindex and the impact factor IF (an average number of items per source). The corresponding function h(IF) is increasing and we show that if the parameter C in the numerator of the shifted Lotka function is high, then the relation between the hindex and the impact factor is almost linear.
Themenfeld: Informetrie
Objekt: hindex

9Egghe, L. ; Guns, R.: Applications of the generalized law of Benford to informetric data.
In: Journal of the American Society for Information Science and Technology. 63(2012) no.8, S.16621665.
(Brief communication)
Abstract: In a previous work (Egghe, 2011), the first author showed that Benford's law (describing the logarithmic distribution of the numbers 1, 2, ... , 9 as first digits of data in decimal form) is related to the classical law of Zipf with exponent 1. The work of Campanario and Coslado (2011), however, shows that Benford's law does not always fit practical data in a statistical sense. In this article, we use a generalization of Benford's law related to the general law of Zipf with exponent ? > 0. Using data from Campanario and Coslado, we apply nonlinear least squares to determine the optimal ? and show that this generalized law of Benford fits the data better than the classical law of Benford.
Themenfeld: Informetrie
Objekt: ZipfGesetz ; BenfordGesetz

10Egghe, L.: Remarks on the paper by A. De Visscher, "what does the gindex really measure?".
In: Journal of the American Society for Information Science and Technology. 63(2012) no.10, S.21182121.
(Brief communication)
Abstract: The author presents a different view on properties of impact measures than given in the paper of De Visscher (2011). He argues that a good impact measure works better when citations are concentrated rather than spread out over articles. The author also presents theoretical evidence that the gindex and the Rindex can be close to the square root of the total number of citations, whereas this is not the case for the Aindex. Here the author confirms an assertion of De Visscher.
Themenfeld: Informetrie
Objekt: gindex

11Egghe, L. ; Guns, R. ; Rousseau, R.: Thoughts on uncitedness : Nobel laureates and Fields medalists as case studies.
In: Journal of the American Society for Information Science and Technology. 62(2011) no.8, S.16371644.
Abstract: Contrary to what one might expect, Nobel laureates and Fields medalists have a rather large fraction (10% or more) of uncited publications. This is the case for (in total) 75 examined researchers from the fields of mathematics (Fields medalists), physics, chemistry, and physiology or medicine (Nobel laureates). We study several indicators for these researchers, including the hindex, total number of publications, average number of citations per publication, the number (and fraction) of uncited publications, and their interrelations. The most remarkable result is a positive correlation between the hindex and the number of uncited articles. We also present a Lotkaian model, which partially explains the empirically found regularities.
Anmerkung: Vgl.: Erratum. In: Journal of the American Society for Information Science and Technology. 63(2012) no.2, S.429.
Themenfeld: Informetrie
Wissenschaftsfach: Mathematik ; Physik ; Chemie ; Medizin
Objekt: NobelPreis ; FielsMedaille

12Egghe, L.: Influence of adding or deleting items and sources on the hindex.
In: Journal of the American Society for Information Science and Technology. 61(2010) no.2, S.370373.
Abstract: Adding or deleting items such as selfcitations has an influence on the hindex of an author. This influence will be proved mathematically in this article. We hereby prove the experimental finding in E. Gianoli and M.A. MolinaMontenegro ([2009]) that the influence of adding or deleting selfcitations on the hindex is greater for low values of the hindex. Why this is logical also is shown by a simple theoretical example. Adding or deleting sources such as adding or deleting minor contributions of an author also has an influence on the hindex of this author; this influence is modeled in this article. This model explains some practical examples found in X. Hu, R. Rousseau, and J. Chen (in press).
Themenfeld: Informetrie
Objekt: hindex

13Egghe, L.: ¬A new short proof of Naranan's theorem, explaining Lotka's law and Zipf's law.
In: Journal of the American Society for Information Science and Technology. 61(2010) no.12, S.25812583.
(Brief communication)
Abstract: Naranan's important theorem, published in Nature in 1970, states that if the number of journals grows exponentially and if the number of articles in each journal grows exponentially (at the same rate for each journal), then the system satisfies Lotka's law and a formula for the Lotka's exponent is given in function of the growth rates of the journals and the articles. This brief communication reproves this result by showing that the system satisfies Zipf's law, which is equivalent with Lotka's law. The proof is short and algebraic and does not use infinitesimal arguments.
Themenfeld: Informetrie
Objekt: NarananTheorem ; ZipfGesetz ; LotkaGesetz

14Egghe, L.: On the relation between the association strength and other similarity measures.
In: Journal of the American Society for Information Science and Technology. 61(2010) no.7, S.15021504.
(Brief communication)
Abstract: A graph in van Eck and Waltman [JASIST, 60(8), 2009, p. 1644], representing the relation between the association strength and the cosine, is partially explained as a sheaf of parabolas, each parabola being the functional relation between these similarity measures on the trajectories x*y=a, a constant. Based on earlier obtained relations between cosine and other similarity measures (e.g., Jaccard index), we can prove new relations between the association strength and these other measures.

15Egghe, L.: Good properties of similarity measures and their complementarity.
In: Journal of the American Society for Information Science and Technology. 61(2010) no.10, S.21512160.
Abstract: Similarity measures, such as the ones of Jaccard, Dice, or Cosine, measure the similarity between two vectors. A good property for similarity measures would be that, if we add a constant vector to both vectors, then the similarity must increase. We show that Dice and Jaccard satisfy this property while Cosine and both overlap measures do not. Adding a constant vector is called, in Lorenz concentration theory, "nominal increase" and we show that the stronger "transfer principle" is not a required good property for similarity measures. Another good property is that, when we have two vectors and if we add one of these vectors to both vectors, then the similarity must increase. Now Dice, Jaccard, Cosine, and one of the overlap measures satisfy this property, while the other overlap measure does not. Also a variant of this latter property is studied.

16Egghe, L.: ¬The Hirsch index and related impact measures.
In: Annual review of information science and technology. 44(2010) no.1, S.65114.
Abstract: Vgl.: http://onlinelibrary.wiley.com/doi/10.1002/aris.2010.1440440109/abstract.
Themenfeld: Literaturübersicht ; Informetrie
Objekt: hindex

17Egghe, L. ; Liang, L. ; Rousseau, R.: ¬A relation between hindex and impact factor in the powerlaw model.
In: Journal of the American Society for Information Science and Technology. 60(2009) no.11, S.23622365.
Abstract: Using a powerlaw model, the two bestknown topics in citation analysis, namely the impact factor and the Hirsch index, are unified into one relation (not a function). The validity of our model is, at least in a qualitative way, confirmed by real data.
Themenfeld: Informetrie
Objekt: hindex

18Egghe, L.: New relations between similarity measures for vectors based on vector norms.
In: Journal of the American Society for Information Science and Technology. 60(2009) no.2, S.232239.
Abstract: The wellknown similarity measures Jaccard, Salton's cosine, Dice, and several related overlap measures for vectors are compared. While general relations are not possible to prove, we study these measures on the trajectories of the form [X]=a[Y], where a > 0 is a constant and [·] denotes the Euclidean norm of a vector. In this case, direct functional relations between these measures are proved. For Jaccard, we prove that it is a convexly increasing function of Salton's cosine measure, but always smaller than or equal to the latter, hereby explaining a curve, experimentally found by Leydesdorff. All the other measures have a linear relation with Salton's cosine, reducing even to equality, in case a = 1. Hence, for equally normed vectors (e.g., for normalized vectors) we, essentially, only have Jaccard's measure and Salton's cosine measure since all the other measures are equal to the latter.

19Egghe, L. ; Leydesdorff, L.: ¬The relation between Pearson's correlation coefficient r and Salton's cosine measure.
In: Journal of the American Society for Information Science and Technology. 60(2009) no.5, S.10271036.
Abstract: The relation between Pearson's correlation coefficient and Salton's cosine measure is revealed based on the different possible values of the division of the L1norm and the L2norm of a vector. These different values yield a sheaf of increasingly straight lines which together form a cloud of points, being the investigated relation. The theoretical results are tested against the author cocitation relations among 24 informetricians for whom two matrices can be constructed, based on cocitations: the asymmetric occurrence matrix and the symmetric cocitation matrix. Both examples completely confirm the theoretical results. The results enable us to specify an algorithm that provides a threshold value for the cosine above which none of the corresponding Pearson correlations would be negative. Using this threshold value can be expected to optimize the visualization of the vector space.
Themenfeld: Informetrie

20Egghe, L.: ¬A rationale for the Hirschindex rankorder distribution and a comparison with the impact factor rankorder distribution.
In: Journal of the American Society for Information Science and Technology. 60(2009) no.10, S.21422144.
Abstract: We present a rationale for the Hirschindex rankorder distribution and prove that it is a power law (hence a straight line in the loglog scale). This is confirmed by experimental data of Pyykkö and by data produced in this article on 206 mathematics journals. This distribution is of a completely different nature than the impact factor (IF) rankorder distribution which (as proved in a previous article) is Sshaped. This is also confirmed by our example. Only in the loglog scale of the hindex distribution do we notice a concave deviation of the straight line for higher ranks. This phenomenon is discussed.
Themenfeld: Informetrie
Objekt: hindex