词条 | Lotka's law | ||||||||||||||||||||||
释义 |
Lotka's law,[1] named after Alfred J. Lotka, is one of a variety of special applications of Zipf's law. It describes the frequency of publication by authors in any given field. It states that the number of authors making contributions in a given period is a fraction of the number making a single contribution, following the formula where a nearly always equals two, i.e., an approximate inverse-square law, where the number of authors publishing a certain number of articles is a fixed ratio to the number of authors publishing a single article. As the number of articles published increases, authors producing that many publications become less frequent. There are 1/4 as many authors publishing two articles within a specified time period as there are single-publication authors, 1/9 as many publishing three articles, 1/16 as many publishing four articles, etc. Though the law itself covers many disciplines, the actual ratios involved (as a function of 'a') are discipline-specific. The general formula says: or where X is the number of publications, Y the relative frequency of authors with X publications, and n and are constants depending on the specific field (). ExampleSay 100 authors write at least one article each over a specific period, we assume for this table that C=100 and n=2. Then the number of authors writing portions of any particular articles in that time period is describe as in the following table:
That would be a total of 294 articles with 155 writers with an average of 1.9 articles for each writer. This is an empirical observation rather than a necessary result. This form of the law is as originally published and is sometimes referred to as the "discrete Lotka power function".[2] Software
See also
References1. ^{{cite journal|author=Lotka, Alfred J.|year=1926|title=The frequency distribution of scientific productivity|journal=Journal of the Washington Academy of Sciences|volume=16|issue=12|pages=317–324}} 2. ^{{cite journal |last=Egghe |first=Leo |year=2005 |title=Relations between the continuous and the discrete Lotka power function|journal=Journal of the American Society for Information Science and Technology |volume=56 |issue=7 |pages=664–668 |doi=10.1002/asi.20157 }} Further reading
External links
2 : Bibliometrics|Statistical laws |
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