Search (31 results, page 1 of 2)

  • × author_ss:"Egghe, L."
  1. Egghe, L.: Properties of the n-overlap vector and n-overlap similarity theory (2006) 0.07
    0.06808342 = product of:
      0.11347236 = sum of:
        0.06342807 = weight(_text_:index in 194) [ClassicSimilarity], result of:
          0.06342807 = score(doc=194,freq=4.0), product of:
            0.18579477 = queryWeight, product of:
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.04251826 = queryNorm
            0.3413878 = fieldWeight in 194, product of:
              2.0 = tf(freq=4.0), with freq of:
                4.0 = termFreq=4.0
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.0390625 = fieldNorm(doc=194)
        0.04035608 = weight(_text_:system in 194) [ClassicSimilarity], result of:
          0.04035608 = score(doc=194,freq=6.0), product of:
            0.13391352 = queryWeight, product of:
              3.1495528 = idf(docFreq=5152, maxDocs=44218)
              0.04251826 = queryNorm
            0.30135927 = fieldWeight in 194, product of:
              2.4494898 = tf(freq=6.0), with freq of:
                6.0 = termFreq=6.0
              3.1495528 = idf(docFreq=5152, maxDocs=44218)
              0.0390625 = fieldNorm(doc=194)
        0.009688215 = product of:
          0.029064644 = sum of:
            0.029064644 = weight(_text_:29 in 194) [ClassicSimilarity], result of:
              0.029064644 = score(doc=194,freq=2.0), product of:
                0.14956595 = queryWeight, product of:
                  3.5176873 = idf(docFreq=3565, maxDocs=44218)
                  0.04251826 = queryNorm
                0.19432661 = fieldWeight in 194, product of:
                  1.4142135 = tf(freq=2.0), with freq of:
                    2.0 = termFreq=2.0
                  3.5176873 = idf(docFreq=3565, maxDocs=44218)
                  0.0390625 = fieldNorm(doc=194)
          0.33333334 = coord(1/3)
      0.6 = coord(3/5)
    
    Abstract
    In the first part of this article the author defines the n-overlap vector whose coordinates consist of the fraction of the objects (e.g., books, N-grams, etc.) that belong to 1, 2, , n sets (more generally: families) (e.g., libraries, databases, etc.). With the aid of the Lorenz concentration theory, a theory of n-overlap similarity is conceived together with corresponding measures, such as the generalized Jaccard index (generalizing the well-known Jaccard index in case n 5 2). Next, the distributional form of the n-overlap vector is determined assuming certain distributions of the object's and of the set (family) sizes. In this section the decreasing power law and decreasing exponential distribution is explained for the n-overlap vector. Both item (token) n-overlap and source (type) n-overlap are studied. The n-overlap properties of objects indexed by a hierarchical system (e.g., books indexed by numbers from a UDC or Dewey system or by N-grams) are presented in the final section. The author shows how the results given in the previous section can be applied as well as how the Lorenz order of the n-overlap vector is respected by an increase or a decrease of the level of refinement in the hierarchical system (e.g., the value N in N-grams).
    Date
    3. 1.2007 14:26:29
  2. Egghe, L.: Influence of adding or deleting items and sources on the h-index (2010) 0.06
    0.057383448 = product of:
      0.14345862 = sum of:
        0.13183276 = weight(_text_:index in 3336) [ClassicSimilarity], result of:
          0.13183276 = score(doc=3336,freq=12.0), product of:
            0.18579477 = queryWeight, product of:
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.04251826 = queryNorm
            0.7095612 = fieldWeight in 3336, product of:
              3.4641016 = tf(freq=12.0), with freq of:
                12.0 = termFreq=12.0
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.046875 = fieldNorm(doc=3336)
        0.011625858 = product of:
          0.034877572 = sum of:
            0.034877572 = weight(_text_:29 in 3336) [ClassicSimilarity], result of:
              0.034877572 = score(doc=3336,freq=2.0), product of:
                0.14956595 = queryWeight, product of:
                  3.5176873 = idf(docFreq=3565, maxDocs=44218)
                  0.04251826 = queryNorm
                0.23319192 = fieldWeight in 3336, product of:
                  1.4142135 = tf(freq=2.0), with freq of:
                    2.0 = termFreq=2.0
                  3.5176873 = idf(docFreq=3565, maxDocs=44218)
                  0.046875 = fieldNorm(doc=3336)
          0.33333334 = coord(1/3)
      0.4 = coord(2/5)
    
    Abstract
    Adding or deleting items such as self-citations has an influence on the h-index of an author. This influence will be proved mathematically in this article. We hereby prove the experimental finding in E. Gianoli and M.A. Molina-Montenegro ([2009]) that the influence of adding or deleting self-citations on the h-index is greater for low values of the h-index. 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 h-index 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).
    Date
    31. 5.2010 15:02:29
    Object
    h-index
  3. Egghe, L.: ¬The influence of transformations on the h-index and the g-index (2008) 0.04
    0.03767435 = product of:
      0.18837175 = sum of:
        0.18837175 = weight(_text_:index in 1881) [ClassicSimilarity], result of:
          0.18837175 = score(doc=1881,freq=18.0), product of:
            0.18579477 = queryWeight, product of:
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.04251826 = queryNorm
            1.01387 = fieldWeight in 1881, product of:
              4.2426405 = tf(freq=18.0), with freq of:
                18.0 = termFreq=18.0
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.0546875 = fieldNorm(doc=1881)
      0.2 = coord(1/5)
    
    Abstract
    In a previous article, we introduced a general transformation on sources and one on items in an arbitrary information production process (IPP). In this article, we investigate the influence of these transformations on the h-index and on the g-index. General formulae that describe this influence are presented. These are applied to the case that the size-frequency function is Lotkaian (i.e., is a decreasing power function). We further show that the h-index of the transformed IPP belongs to the interval bounded by the two transformations of the h-index of the original IPP, and we also show that this property is not true for the g-index.
    Object
    h-index
    g-index
  4. Egghe, L.; Rousseau, R.: ¬An h-index weighted by citation impact (2008) 0.03
    0.032092348 = product of:
      0.16046174 = sum of:
        0.16046174 = weight(_text_:index in 695) [ClassicSimilarity], result of:
          0.16046174 = score(doc=695,freq=10.0), product of:
            0.18579477 = queryWeight, product of:
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.04251826 = queryNorm
            0.86365044 = fieldWeight in 695, product of:
              3.1622777 = tf(freq=10.0), with freq of:
                10.0 = termFreq=10.0
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.0625 = fieldNorm(doc=695)
      0.2 = coord(1/5)
    
    Abstract
    An h-type index is proposed which depends on the obtained citations of articles belonging to the h-core. This weighted h-index, denoted as hw, is presented in a continuous setting and in a discrete one. It is shown that in a continuous setting the new index enjoys many good properties. In the discrete setting some small deviations from the ideal may occur.
    Object
    h-index
  5. Egghe, L.; Rousseau, R.: ¬The Hirsch index of a shifted Lotka function and its relation with the impact factor (2012) 0.03
    0.03076098 = product of:
      0.1538049 = sum of:
        0.1538049 = weight(_text_:index in 243) [ClassicSimilarity], result of:
          0.1538049 = score(doc=243,freq=12.0), product of:
            0.18579477 = queryWeight, product of:
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.04251826 = queryNorm
            0.82782143 = fieldWeight in 243, product of:
              3.4641016 = tf(freq=12.0), with freq of:
                12.0 = termFreq=12.0
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.0546875 = fieldNorm(doc=243)
      0.2 = coord(1/5)
    
    Abstract
    Based on earlier results about the shifted Lotka function, we prove an implicit functional relation between the Hirsch index (h-index) 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 h-index 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 h-index and the impact factor is almost linear.
    Object
    h-index
  6. Egghe, L.: Note on a possible decomposition of the h-Index (2013) 0.03
    0.030445471 = product of:
      0.15222736 = sum of:
        0.15222736 = weight(_text_:index in 683) [ClassicSimilarity], result of:
          0.15222736 = score(doc=683,freq=4.0), product of:
            0.18579477 = queryWeight, product of:
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.04251826 = queryNorm
            0.8193307 = fieldWeight in 683, product of:
              2.0 = tf(freq=4.0), with freq of:
                4.0 = termFreq=4.0
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.09375 = fieldNorm(doc=683)
      0.2 = coord(1/5)
    
    Object
    h-index
  7. Egghe, L.: ¬The Hirsch index and related impact measures (2010) 0.03
    0.030445471 = product of:
      0.15222736 = sum of:
        0.15222736 = weight(_text_:index in 1597) [ClassicSimilarity], result of:
          0.15222736 = score(doc=1597,freq=4.0), product of:
            0.18579477 = queryWeight, product of:
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.04251826 = queryNorm
            0.8193307 = fieldWeight in 1597, product of:
              2.0 = tf(freq=4.0), with freq of:
                4.0 = termFreq=4.0
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.09375 = fieldNorm(doc=1597)
      0.2 = coord(1/5)
    
    Object
    h-index
  8. Egghe, L.: Remarks on the paper by A. De Visscher, "what does the g-index really measure?" (2012) 0.03
    0.028080804 = product of:
      0.14040402 = sum of:
        0.14040402 = weight(_text_:index in 463) [ClassicSimilarity], result of:
          0.14040402 = score(doc=463,freq=10.0), product of:
            0.18579477 = queryWeight, product of:
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.04251826 = queryNorm
            0.75569415 = fieldWeight in 463, product of:
              3.1622777 = tf(freq=10.0), with freq of:
                10.0 = termFreq=10.0
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.0546875 = fieldNorm(doc=463)
      0.2 = coord(1/5)
    
    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 g-index and the R-index can be close to the square root of the total number of citations, whereas this is not the case for the A-index. Here the author confirms an assertion of De Visscher.
    Object
    g-index
  9. Egghe, L.: Mathematical theory of the h- and g-index in case of fractional counting of authorship (2008) 0.03
    0.026366552 = product of:
      0.13183276 = sum of:
        0.13183276 = weight(_text_:index in 2004) [ClassicSimilarity], result of:
          0.13183276 = score(doc=2004,freq=12.0), product of:
            0.18579477 = queryWeight, product of:
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.04251826 = queryNorm
            0.7095612 = fieldWeight in 2004, product of:
              3.4641016 = tf(freq=12.0), with freq of:
                12.0 = termFreq=12.0
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.046875 = fieldNorm(doc=2004)
      0.2 = coord(1/5)
    
    Abstract
    This article studies the h-index (Hirsch index) and the g-index of authors, in case one counts authorship of the cited articles in a fractional way. There are two ways to do this: One counts the citations to these papers in a fractional way or one counts the ranks of the papers in a fractional way as credit for an author. In both cases, we define the fractional h- and g-indexes, and we present inequalities (both upper and lower bounds) between these fractional h- and g-indexes and their corresponding unweighted values (also involving, of course, the coauthorship distribution). Wherever applicable, examples and counterexamples are provided. In a concrete example (the publication citation list of the present author), we make explicit calculations of these fractional h- and g-indexes and show that they are not very different from the unweighted ones.
    Object
    h-index
    g-index
  10. Egghe, L.: ¬A good normalized impact and concentration measure (2014) 0.03
    0.025371227 = product of:
      0.12685613 = sum of:
        0.12685613 = weight(_text_:index in 1508) [ClassicSimilarity], result of:
          0.12685613 = score(doc=1508,freq=4.0), product of:
            0.18579477 = queryWeight, product of:
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.04251826 = queryNorm
            0.6827756 = fieldWeight in 1508, product of:
              2.0 = tf(freq=4.0), with freq of:
                4.0 = termFreq=4.0
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.078125 = fieldNorm(doc=1508)
      0.2 = coord(1/5)
    
    Abstract
    It is shown that a normalized version of the g-index is a good normalized impact and concentration measure. A proposal for such a measure by Bartolucci is improved.
    Object
    g-index
  11. Egghe, L.: ¬A rationale for the Hirsch-index rank-order distribution and a comparison with the impact factor rank-order distribution (2009) 0.03
    0.025116233 = product of:
      0.12558116 = sum of:
        0.12558116 = weight(_text_:index in 3124) [ClassicSimilarity], result of:
          0.12558116 = score(doc=3124,freq=8.0), product of:
            0.18579477 = queryWeight, product of:
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.04251826 = queryNorm
            0.67591333 = fieldWeight in 3124, product of:
              2.828427 = tf(freq=8.0), with freq of:
                8.0 = termFreq=8.0
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.0546875 = fieldNorm(doc=3124)
      0.2 = coord(1/5)
    
    Abstract
    We present a rationale for the Hirsch-index rank-order distribution and prove that it is a power law (hence a straight line in the log-log 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) rank-order distribution which (as proved in a previous article) is S-shaped. This is also confirmed by our example. Only in the log-log scale of the h-index distribution do we notice a concave deviation of the straight line for higher ranks. This phenomenon is discussed.
    Object
    h-index
  12. Egghe, L.; Liang, L.; Rousseau, R.: ¬A relation between h-index and impact factor in the power-law model (2009) 0.02
    0.024858627 = product of:
      0.12429313 = sum of:
        0.12429313 = weight(_text_:index in 6759) [ClassicSimilarity], result of:
          0.12429313 = score(doc=6759,freq=6.0), product of:
            0.18579477 = queryWeight, product of:
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.04251826 = queryNorm
            0.6689808 = fieldWeight in 6759, product of:
              2.4494898 = tf(freq=6.0), with freq of:
                6.0 = termFreq=6.0
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.0625 = fieldNorm(doc=6759)
      0.2 = coord(1/5)
    
    Abstract
    Using a power-law model, the two best-known 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.
    Object
    h-index
  13. Egghe, L.: Dynamic h-index : the Hirsch index in function of time (2007) 0.02
    0.024858627 = product of:
      0.12429313 = sum of:
        0.12429313 = weight(_text_:index in 147) [ClassicSimilarity], result of:
          0.12429313 = score(doc=147,freq=6.0), product of:
            0.18579477 = queryWeight, product of:
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.04251826 = queryNorm
            0.6689808 = fieldWeight in 147, product of:
              2.4494898 = tf(freq=6.0), with freq of:
                6.0 = termFreq=6.0
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.0625 = fieldNorm(doc=147)
      0.2 = coord(1/5)
    
    Abstract
    When there are a group of articles and the present time is fixed we can determine the unique number h being the number of articles that received h or more citations while the other articles received a number of citations which is not larger than h. In this article, the time dependence of the h-index is determined. This is important to describe the expected career evolution of a scientist's work or of a journal's production in a fixed year.
  14. Egghe, L.; Rousseau, R.: Averaging and globalising quotients of informetric and scientometric data (1996) 0.02
    0.02397574 = product of:
      0.059939347 = sum of:
        0.04841807 = weight(_text_:context in 7659) [ClassicSimilarity], result of:
          0.04841807 = score(doc=7659,freq=2.0), product of:
            0.17622331 = queryWeight, product of:
              4.14465 = idf(docFreq=1904, maxDocs=44218)
              0.04251826 = queryNorm
            0.27475408 = fieldWeight in 7659, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              4.14465 = idf(docFreq=1904, maxDocs=44218)
              0.046875 = fieldNorm(doc=7659)
        0.011521274 = product of:
          0.03456382 = sum of:
            0.03456382 = weight(_text_:22 in 7659) [ClassicSimilarity], result of:
              0.03456382 = score(doc=7659,freq=2.0), product of:
                0.1488917 = queryWeight, product of:
                  3.5018296 = idf(docFreq=3622, maxDocs=44218)
                  0.04251826 = queryNorm
                0.23214069 = fieldWeight in 7659, product of:
                  1.4142135 = tf(freq=2.0), with freq of:
                    2.0 = termFreq=2.0
                  3.5018296 = idf(docFreq=3622, maxDocs=44218)
                  0.046875 = fieldNorm(doc=7659)
          0.33333334 = coord(1/3)
      0.4 = coord(2/5)
    
    Abstract
    It is possible, using ISI's Journal Citation Report (JCR), to calculate average impact factors (AIF) for LCR's subject categories but it can be more useful to know the global Impact Factor (GIF) of a subject category and compare the 2 values. Reports results of a study to compare the relationships between AIFs and GIFs of subjects, based on the particular case of the average impact factor of a subfield versus the impact factor of this subfield as a whole, the difference being studied between an average of quotients, denoted as AQ, and a global average, obtained as a quotient of averages, and denoted as GQ. In the case of impact factors, AQ becomes the average impact factor of a field, and GQ becomes its global impact factor. Discusses a number of applications of this technique in the context of informetrics and scientometrics
    Source
    Journal of information science. 22(1996) no.3, S.165-170
  15. Egghe, L.: Mathematical study of h-index sequences (2009) 0.02
    0.021972127 = product of:
      0.10986064 = sum of:
        0.10986064 = weight(_text_:index in 4217) [ClassicSimilarity], result of:
          0.10986064 = score(doc=4217,freq=12.0), product of:
            0.18579477 = queryWeight, product of:
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.04251826 = queryNorm
            0.591301 = fieldWeight in 4217, product of:
              3.4641016 = tf(freq=12.0), with freq of:
                12.0 = termFreq=12.0
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.0390625 = fieldNorm(doc=4217)
      0.2 = coord(1/5)
    
    Abstract
    This paper studies mathematical properties of h-index sequences as developed by Liang [Liang, L. (2006). h-Index sequence and h-index matrix: Constructions and applications. Scientometrics, 69(1), 153-159]. For practical reasons, Liming studies such sequences where the time goes backwards while it is more logical to use the time going forward (real career periods). Both type of h-index sequences are studied here and their interrelations are revealed. We show cases where these sequences are convex, linear and concave. We also show that, when one of the sequences is convex then the other one is concave, showing that the reverse-time sequence, in general, cannot be used to derive similar properties of the (difficult to obtain) forward time sequence. We show that both sequences are the same if and only if the author produces the same number of papers per year. If the author produces an increasing number of papers per year, then Liang's h-sequences are above the "normal" ones. All these results are also valid for g- and R-sequences. The results are confirmed by the h-, g- and R-sequences (forward and reverse time) of the author.
    Object
    h-index
  16. Egghe, L.; Ravichandra Rao, I.K.: Study of different h-indices for groups of authors (2008) 0.02
    0.0215282 = product of:
      0.107641 = sum of:
        0.107641 = weight(_text_:index in 1878) [ClassicSimilarity], result of:
          0.107641 = score(doc=1878,freq=8.0), product of:
            0.18579477 = queryWeight, product of:
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.04251826 = queryNorm
            0.5793543 = fieldWeight in 1878, product of:
              2.828427 = tf(freq=8.0), with freq of:
                8.0 = termFreq=8.0
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.046875 = fieldNorm(doc=1878)
      0.2 = coord(1/5)
    
    Abstract
    In this article, for any group of authors, we define three different h-indices. First, there is the successive h-index h2 based on the ranked list of authors and their h-indices h1 as defined by Schubert (2007). Next, there is the h-index hP based on the ranked list of authors and their number of publications. Finally, there is the h-index hC based on the ranked list of authors and their number of citations. We present formulae for these three indices in Lotkaian informetrics from which it also follows that h2 < hp < hc. We give a concrete example of a group of 167 authors on the topic optical flow estimation. Besides these three h-indices, we also calculate the two-by-two Spearman rank correlation coefficient and prove that these rankings are significantly related.
    Object
    h-index
  17. Egghe, L.; Ravichandra Rao, I.K.: ¬The influence of the broadness of a query of a topic on its h-index : models and examples of the h-index of n-grams (2008) 0.02
    0.020057717 = product of:
      0.100288585 = sum of:
        0.100288585 = weight(_text_:index in 2009) [ClassicSimilarity], result of:
          0.100288585 = score(doc=2009,freq=10.0), product of:
            0.18579477 = queryWeight, product of:
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.04251826 = queryNorm
            0.5397815 = fieldWeight in 2009, product of:
              3.1622777 = tf(freq=10.0), with freq of:
                10.0 = termFreq=10.0
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.0390625 = fieldNorm(doc=2009)
      0.2 = coord(1/5)
    
    Abstract
    The article studies the influence of the query formulation of a topic on its h-index. In order to generate pure random sets of documents, we used N-grams (N variable) to measure this influence: strings of zeros, truncated at the end. The used databases are WoS and Scopus. The formula h=T**1/alpha, proved in Egghe and Rousseau (2006) where T is the number of retrieved documents and is Lotka's exponent, is confirmed being a concavely increasing function of T. We also give a formula for the relation between h and N the length of the N-gram: h=D10**(-N/alpha) where D is a constant, a convexly decreasing function, which is found in our experiments. Nonlinear regression on h=T**1/alpha gives an estimation of , which can then be used to estimate the h-index of the entire database (Web of Science [WoS] and Scopus): h=S**1/alpha, , where S is the total number of documents in the database.
    Object
    h-index
  18. Egghe, L.; Guns, R.; Rousseau, R.: Thoughts on uncitedness : Nobel laureates and Fields medalists as case studies (2011) 0.02
    0.015222736 = product of:
      0.07611368 = sum of:
        0.07611368 = weight(_text_:index in 4994) [ClassicSimilarity], result of:
          0.07611368 = score(doc=4994,freq=4.0), product of:
            0.18579477 = queryWeight, product of:
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.04251826 = queryNorm
            0.40966535 = fieldWeight in 4994, product of:
              2.0 = tf(freq=4.0), with freq of:
                4.0 = termFreq=4.0
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.046875 = fieldNorm(doc=4994)
      0.2 = coord(1/5)
    
    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 h-index, 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 h-index and the number of uncited articles. We also present a Lotkaian model, which partially explains the empirically found regularities.
  19. Egghe, L.: On the relation between the association strength and other similarity measures (2010) 0.01
    0.014352133 = product of:
      0.07176066 = sum of:
        0.07176066 = weight(_text_:index in 3598) [ClassicSimilarity], result of:
          0.07176066 = score(doc=3598,freq=2.0), product of:
            0.18579477 = queryWeight, product of:
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.04251826 = queryNorm
            0.3862362 = fieldWeight in 3598, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              4.369764 = idf(docFreq=1520, maxDocs=44218)
              0.0625 = fieldNorm(doc=3598)
      0.2 = coord(1/5)
    
    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.
  20. Egghe, L.: Existence theorem of the quadruple (P, R, F, M) : precision, recall, fallout and miss (2007) 0.01
    0.011183805 = product of:
      0.055919025 = sum of:
        0.055919025 = weight(_text_:system in 2011) [ClassicSimilarity], result of:
          0.055919025 = score(doc=2011,freq=8.0), product of:
            0.13391352 = queryWeight, product of:
              3.1495528 = idf(docFreq=5152, maxDocs=44218)
              0.04251826 = queryNorm
            0.41757566 = fieldWeight in 2011, product of:
              2.828427 = tf(freq=8.0), with freq of:
                8.0 = termFreq=8.0
              3.1495528 = idf(docFreq=5152, maxDocs=44218)
              0.046875 = fieldNorm(doc=2011)
      0.2 = coord(1/5)
    
    Abstract
    In an earlier paper [Egghe, L. (2004). A universal method of information retrieval evaluation: the "missing" link M and the universal IR surface. Information Processing and Management, 40, 21-30] we showed that, given an IR system, and if P denotes precision, R recall, F fallout and M miss (re-introduced in the paper mentioned above), we have the following relationship between P, R, F and M: P/(1-P)*(1-R)/R*F/(1-F)*(1-M)/M = 1. In this paper we prove the (more difficult) converse: given any four rational numbers in the interval ]0, 1[ satisfying the above equation, then there exists an IR system such that these four numbers (in any order) are the precision, recall, fallout and miss of this IR system. As a consequence we show that any three rational numbers in ]0, 1[ represent any three measures taken from precision, recall, fallout and miss of a certain IR system. We also show that this result is also true for two numbers instead of three.