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Ahlgren, P.; Jarneving, B.; Rousseau, R.: Requirements for a cocitation similarity measure, with special reference to Pearson's correlation coefficient (2003)
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- Abstract
- Ahlgren, Jarneving, and. Rousseau review accepted procedures for author co-citation analysis first pointing out that since in the raw data matrix the row and column values are identical i,e, the co-citation count of two authors, there is no clear choice for diagonal values. They suggest the number of times an author has been co-cited with himself excluding self citation rather than the common treatment as zeros or as missing values. When the matrix is converted to a similarity matrix the normal procedure is to create a matrix of Pearson's r coefficients between data vectors. Ranking by r and by co-citation frequency and by intuition can easily yield three different orders. It would seem necessary that the adding of zeros to the matrix will not affect the value or the relative order of similarity measures but it is shown that this is not the case with Pearson's r. Using 913 bibliographic descriptions form the Web of Science of articles form JASIS and Scientometrics, authors names were extracted, edited and 12 information retrieval authors and 12 bibliometric authors each from the top 100 most cited were selected. Co-citation and r value (diagonal elements treated as missing) matrices were constructed, and then reconstructed in expanded form. Adding zeros can both change the r value and the ordering of the authors based upon that value. A chi-squared distance measure would not violate these requirements, nor would the cosine coefficient. It is also argued that co-citation data is ordinal data since there is no assurance of an absolute zero number of co-citations, and thus Pearson is not appropriate. The number of ties in co-citation data make the use of the Spearman rank order coefficient problematic.
- Date
- 9. 7.2006 10:22:35
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Impe, S. van; Rousseau, R.: Web-to-print citations and the humanities (2006)
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- Abstract
- References to printed documents made on the web are called web-to-print references. These printed documents then in turn receive web-to-print citations. Webto-print citations and web-to-print references are the topic of this article, in which we study the online impact of printed sources. Web-to-print citations are discussed from a structural point of view and a small-scale experiment related to web-to-print citations for local history journals is performed. The main research question in setting up this experiment concerns the possibility of using web-to-print citations as a substitute for classical citation indexes by gauging the importance, visibility and impact of journals in the humanities. Results show the importance of web bibliographies in the field, but, at least for what concerns the journals and the period studied here, the amount of received web-to-print citations is too small to draw general conclusions.
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Asonuma, A.; Fang, Y.; Rousseau, R.: Reflections on the age distribution of Japanese scientists (2006)
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- Abstract
- The age distribution of a country's scientists is an important element in the study of its research capacity. In this article we investigate the age distribution of Japanese scientists in order to find out whether major events such as World War II had an appreciable effect on its features. Data have been obtained from population censuses taken in Japan from 1970 to 1995. A comparison with the situation in China and the United States has been made. We find that the group of scientific researchers outside academia is dominated by the young: those younger than age 35. The personnel group in higher education, on the other hand, is dominated by the baby boomers: those who were born after World War II. Contrary to the Chinese situation we could not find any influence of major nondemographic events. The only influence we found was the increase in enrollment of university students after World War II caused by the reform of the Japanese university system. Female participation in the scientific and university systems in Japan, though still low, is increasing.
- Date
- 22. 7.2006 15:26:24
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Egghe, L.; Rousseau, R.; Hooydonk, G. van: Methods for accrediting publications to authors or countries : consequences for evaluation studies (2000)
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- Abstract
- One aim of science evaluation studies is to determine quantitatively the contribution of different players (authors, departments, countries) to the whole system. This information is then used to study the evolution of the system, for instance to gauge the results of special national or international programs. Taking articles as our basic data, we want to determine the exact relative contribution of each coauthor or each country. These numbers are brought together to obtain country scores, or department scores, etc. It turns out, as we will show in this article, that different scoring methods can yield totally different rankings. Conseqeuntly, a ranking between countries, universities, research groups or authors, based on one particular accrediting methods does not contain an absolute truth about their relative importance
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Frandsen, T.F.; Rousseau, R.: Article impact calculated over arbitrary periods (2005)
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- Date
- 20. 3.2005 10:29:08
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Liang, L.; Rousseau, R.: Yield sequences as journal attractivity indicators : "payback times" for Science and Nature (2008)
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- Date
- 21. 3.2008 14:29:54
