Search (21 results, page 1 of 2)

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Abstract

The research question studied in this contribution is how to find an adequate representation to describe the diffusion of scientific ideas over time. We claim that citation data, at least of articles that act as concept symbols, can be considered to contain this information. As a case study we show how the founding article by Nobel Prize winner Kao illustrates the evolution of the field of fiber optics communication. We use a continuous description of discrete citation data in order to accentuate turning points and breakthroughs in the history of this field. Applying the principles explained in this contribution informetrics may reveal the trajectories along which science is developing.

Source

Information processing and management. 48(2012) no.4, S.791-801

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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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Source

Journal of information science. 22(1996) no.3, S.165-170

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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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Source

Information processing and management. 30(1994) no.2, S.267-277

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Abstract

Observed aging curves are influenced by publication delays. In this article, we show how the 'undisturbed' aging function and the publication delay combine to give the observed aging function. This combination is performed by a mathematical operation known as convolution. Examples are given, such as the convolution of 2 Poisson distributions, 2 exponential distributions, a 2 lognormal distributions. A paradox is observed between theory and real data

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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.

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Abstract

Using citation data of articles written by some Nobel Prize winners in physics, we show that concave, convex, and straight curves represent different types of interactions between old ideas and new insights. These cases illustrate different diffusion characteristics of academic knowledge, depending on the nature of the knowledge in the new publications. This work adds to the study of the development of science and links this development to citation analysis.

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Abstract

Several characteristics of classical Lorenz curves make them unsuitable for the study of a group of topperformers. TOP-curves, defined as a kind of mirror image of TIP-curves used in poverty studies, are shown to possess the properties necessary for adequate empirical ranking of various data arrays, based on the properties of the highest performers (i.e., the core). TOP-curves and essential TOP-curves, also introduced in this article, simultaneously represent the incidence, intensity, and inequality among the top. It is shown that TOPdominance partial order, introduced in this article, is stronger than Lorenz dominance order. In this way, this article contributes to the study of cores, a central issue in applied informetrics.

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Abstract

Temporal growth of the h-index in a diachronous cumulative time series is predicted to be linear by Hirsch (2005), whereas other models predict a concave increase. Actual data generally yield a linear growth or S-shaped growth. We study the h-index's growth in computer simulations of the publication-citation process. In most simulations the h-index grows linearly in time. Only occasionally does an S-shape occur, while in our simulations a concave increase is very rare. The latter is often signalled by the occurrence of plateaus - periods of h-index stagnation. Several parameters and their influence on the h-index's growth are determined and discussed.

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Source

Information processing and management. 34(1998) nos.2/3, S.191-218

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Source

Information processing and management. 44(2008) no.2, S.770-780

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Date

14. 2.2012 12:53:22

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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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Abstract

Intellectual and technological talents and skills are the driving force for scientific and industrial development, especially in our times characterized by a knowledgebased economy. Major events in society and related political decisions, however, can have a long-term effect an a country's scientific weIl-being. Although the Cultural Revolution took place from 1966 to 1976, its aftermath can still be felt. This is shown by this study of the production and productivity of Chinese scientists as a function of their age. Based an the 1995-2000 data from the Chinese Science Citation database (CSCD), this article investigates the year-by-year age distribution of scientific and technological personnel publishing in China. It is shown that the "Talent Fault" originating during the Cultural Revolution still exists, and that a new gap resulting from recent brain drain might be developing. The purpose of this work is to provide necessary information about the current situation and especially the existing problems of the S&T workforce in China.

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Abstract

Fractional counting of authors of multi-authored papers has been shown to lead to a breakdown of Lotka's Law despite its robust character under most circumstances. Kretschmer and Rousseau use the normal count method of full credit for each author on two five-year bibliographies from each of 13 Dutch physics institutes where high co-authorship is a common occurrence. Kolmogorov-Smirnov tests were preformed to see if the Lotka distribution fit the data. All bibliographies up to 40 authors fit acceptably; no bibliography with a paper with over 100 authors fits the distribution. The underlying traditional "success breeds success" mechanism assumes new items on a one by one basis, but Egghe's generalized model would still account for the process. It seems unlikely that Lotka's Law will hold in a high co-authorship environment.

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Abstract

Purpose - This paper aims to introduce a general framework for the analysis of knowledge integration and diffusion using bibliometric data. Design/methodology/approach - The authors propose that in order to characterise knowledge integration and diffusion of a given issue (the source, for example articles on a topic or by an organisation, etc.), one has to choose a set of elements from the source (the intermediary set, for example references, keywords, etc.). This set can then be classified into categories (cats), thus making it possible to investigate its diversity. The set can also be characterised according to the coherence of a network associated to it. Findings - This framework allows a methodology to be developed to assess knowledge integration and diffusion. Such methodologies can be useful for a number of science policy issues, including the assessment of interdisciplinarity in research and dynamics of research networks. Originality/value - The main contribution of this article is to provide a simple and easy to use generalisation of an existing approach to study interdisciplinarity, bringing knowledge integration and knowledge diffusion together in one framework.

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Abstract

Measurement of the degree of interconnectedness in graph like networks of hyperlinks or citations can indicate the existence of research fields and assist in comparative evaluation of research efforts. In this issue we begin with Egghe and Rousseau who review compactness measures and investigate the compactness of a network as a weighted graph with dissimilarity values characterizing the arcs between nodes. They make use of a generalization of the Botofogo, Rivlin, Shneiderman, (BRS) compaction measure which treats the distance between unreachable nodes not as infinity but rather as the number of nodes in the network. The dissimilarity values are determined by summing the reciprocals of the weights of the arcs in the shortest chain between two nodes where no weight is smaller than one. The BRS measure is then the maximum value for the sum of the dissimilarity measures less the actual sum divided by the difference between the maximum and minimum. The Wiener index, the sum of all elements in the dissimilarity matrix divided by two, is then computed for Small's particle physics co-citation data as well as the BRS measure, the dissimilarity values and shortest paths. The compactness measure for the weighted network is smaller than for the un-weighted. When the bibliographic coupling network is utilized it is shown to be less compact than the co-citation network which indicates that the new measure produces results that confirm to an obvious case.

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Abstract

Purpose - The purpose of this paper is to clarify earlier work on journal diffusion metrics. Classical journal indicators such as the Garfield impact factor do not measure the breadth of influence across the literature of a particular journal title. As a new approach to measuring research influence, the study complements these existing metrics with a series of formally described diffusion factors. Design/methodology/approach - Using a publication-citation matrix as an organising construct, the paper develops formal descriptions of two forms of diffusion metric: "relative diffusion factors" and "journal diffusion factors" in both their synchronous and diachronous forms. It also provides worked examples for selected library and information science and economics journals, plus a sample of health information papers to illustrate their construction and use. Findings - Diffusion factors capture different aspects of the citation reception process than existing bibliometric measures. The paper shows that diffusion factors can be applied at the whole journal level or for sets of articles and that they provide a richer evidence base for citation analyses than traditional measures alone. Research limitations/implications - The focus of this paper is on clarifying the concepts underlying diffusion factors and there is unlimited scope for further work to apply these metrics to much larger and more comprehensive data sets than has been attempted here. Practical implications - These new tools extend the range of tools available for bibliometric, and possibly webometric, analysis. Diffusion factors might find particular application in studies where the research questions focus on the dynamic aspects of innovation and knowledge transfer. Originality/value - This paper will be of interest to those with theoretical interests in informetric distributions as well as those interested in science policy and innovation studies.