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Abstract  

Citation network analysis is an effective tool to analyze the structure of scientific research. Clustering is often used to visualize scientific domain and to detect emerging research front there. While we often set arbitrarily clustering threshold, there is few guide to set appropriate threshold. This study analyzed basic process how clustering of citation network proceeds by tracking size and modularity change during clustering. We found that there are three stages in clustering of citation networks and it is universal across our case studies. In the first stage, core clusters in the domain are formed. In the second stage, peripheral clusters are formed, while core clusters continue to grow. In the third stage, core clusters grow again. We found the minimum corpus size around one hundred assuring the clustering. When the corpus size is less than one hundred, clustered network structure tends to be more random. In addition even for the corpus whose size is larger than it, the clustering quality for some clusters formed in the later stage is low. These results give a fundamental guidance to the user of citation network analysis.

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Abstract  

This article offers information on the characteristics and number of materials research articles indexed in the Science Citation Index (SCI) database in the year of 2004. 22,843 articles in full-text forms from 169 journals from the materials field (which included ceramics, metallurgy, and polymer journals) were retrieved from the SCI database and exported to EndNote software. The retrieved articles were carefully analyzed by eight scientists and experts in those subfields and categorized using SPSS into eight different categories, being (1) New materials, (2) Materials characterizations, (3) Materials improvement, (4) New process and/or process improvement, (5) Mathematical and theoretical models and/or computer simulations, (6) Novel and comprehensive explanations, (7) Testing conditions, and (8) Comparative studies, whose definitions were clearly indicated. The results were then considered in terms of the percentage of the number of articles in each materials subfield, country of corresponding author, and number of authors. The overall results suggested that, most materials articles published in 2004 were focused on new process and process improvement (27%), while materials characterizations (23%) and testing conditions (12%) took the 2nd and 3rd places, especially for the ceramics and polymer articles. The highest numbers of articles in the ceramics and polymer subfields were focused on new processes and/or process improvement, and those for the metallurgy subfield were on materials characterization. In the SCI database, the largest number of materials articles was authored from Asian scientists although the majority of the materials journals were run by editors from Europe in North America/Canada continents. There was no coherent relationship between the authors’ and editors’ affiliations. China, Japan and the United States of America (USA) were shown to be the top three countries which had the highest publication numbers in the materials field. Japan had the highest publication numbers in the ceramics subfield while China possessed most publications in polymer and metallurgy subfields. However, when considering the journal impact factors, the leading positions of the countries changed. The results from this work could assist materials scientists to select suitable international journals in relevant association with the contents of their to-publish works. Finally, it was noted that most material research articles were written by 3–4 authorships.

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Introduction Since Narin and his colleagues pioneered and further developed ‘patent citation analysis’ (Narin and Noma 1985 ; Narin et al. 1997 ; Narin and Olivastro 1998 ), an optimal method to analyze the interaction

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in nano science and engineering. We also study the structure of citation network of the papers authored by these scientists. The co-author network is a type of social network and the paper citation network is a type of information science network

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Abstract  

On the basis of investigating author's opinion on citing motivations of chemistry papers aquasi-quantitative model for citing is suggested. The model selects professional and nonprofessional motivations of citing and introduces thecitation threshold concept which tries to characterize the effect of citing motivations quantitatively. Possible reasons for missing citations are also treated. Mean ages of real and of self-citations were calculated by subtracting the average of the publication years of cited papers from the publication year of the citing publication. The difference between the mean ages may characterize thesynchronity of the author's research in comparison with those working on similar topics. The paper introduces thecitation strategy indicator which relates impact factors of cited periodicals with the mean impact factor of periodicals in the corresponding research subfield.

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Introduction The major challenge in comparative bibliometric research assessment has been to find a single meaningful indicator from the quantity data (the number of papers P published), the quasity term (citations C

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Summary  

Are prior self-citations an effective input in increasing a subsequent article's citation count? Examination of 418 articles in eight economics journals found that, after controlling for article length, journal and author quality, lead article position, and coauthorship, an author's prior stock of self-citations is not statistically related to a subsequent article's total citation count or the quality of the journals in which those citations appear. Self-citations that appear in prestigious high-impact economics journals have a statistically positive, but numerically small, effect on a subsequent article's total citation count and on the quality of the citing journal. The productive effect of a prior self-citation is inversely related to its age. Prior self-citations of the second author listed in a collaborative article have no significant effect on a subsequent article's total citation count or the quality of the economics journals in which those citations appear.

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networks (Shin and Park 2007 ; Wartburg et al. 2005 ; Yoon and Park 2004 ). A patent citation network consists of groups of related patents in which the largest groups are defined by patent technology categories. The exchange of citations between these

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Abstract  

The method of classifying citations according to the context in the citing paper, previously developed by the authors, is applied to the study of scientific revolutions. In particular, the BCS theory of superconductivity ind the non-conservation of parity are investigated. The results can be easily interpreted in terms of the characteristic features of these discoveries. It is suggested that these two examples represent two different types of paradigm changes, thus prompting a considerable refinement of the usual dichotomous picture of normal vs. breakthrough science.

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content analysis to educational articles published in five Social Sciences Citation Index (SSCI) journals from 2001 to 2005 to study e-learning developments and future trends. In both cases, these studies offer in-depth understanding of e

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