共查询到20条相似文献，搜索用时 15 毫秒
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Recently Woeginger [Woeginger, G. H. (2008-a). An axiomatic characterization for the Hirsch-index. Mathematical Social Sciences. An axiomatic analysis of Egghe's g-index. Journal of Informetrics] introduced a set of axioms for scientific impact measures. These lead to a characterization of the h-index. In this note we consider a slight generalization and check which of Woeginger's axioms are satisfied by the g-index, the h(2)-index and the R2-index. 相似文献
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In order to take multiple co-authorship appropriately into account, a straightforward modification of the Hirsch index was recently proposed. Fractionalised counting of the papers yields an appropriate measure which is called the hm-index. The effect of this procedure is compared in the present work with other variants of the h-index and found to be superior to the fractionalised counting of citations and to the normalization of the h-index with the average number of authors in the h-core. Three fictitious examples for model cases and one empirical case are analysed. 相似文献
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The structure of different types of time series in citation analysis is revealed, using an adapted form of the Frandsen–Rousseau notation. Special cases where this approach can be used include time series of impact factors and time series of h-indices, or h-type indices. This leads to a tool describing dynamic aspects of citation analysis. Time series of h-indices are calculated in some specific models. 相似文献
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Gopalan M. Nair 《Journal of Informetrics》2012,6(1):80-87
A variant of the h-index, named the stochastic h-index, is proposed. This new index is obtained by adding to the h-index the probability, under a specific stochastic model, that the h-index will increase by one or more within a given time interval. The stochastic h-index thus extends the h-index to the real line and has a direct interpretation as the distance to the next higher index value. We show how the stochastic h-index can be evaluated and compare it with other variants of the h-index which purportedly indicate the distance to a higher h-index. 相似文献
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An expert ranking of forestry journals was compared with Journal Impact Factors and h-indices computed from the ISI Web of Science and internet-based data. Citations reported by Google Scholar offer an efficient way to rank all journals objectively, in a manner consistent with other indicators. This h-index exhibited a high correlation with the Journal Impact Factor (r = 0.92), but is not confined to journals selected by any particular commercial provider. A ranking of 180 forestry journals is presented, on the basis of this index. 相似文献
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Antonio Quesada 《Journal of Informetrics》2011,5(3):476-480
The Hirsch index and the Egghe index are both numbers that synthesize a researcher's output. The h-index associated with researcher r is the maximum number h such that r has h papers with at least h citations each. The g-index is the maximum number g of papers by r such that the average number of citations of the g papers is at least g. Both indices are characterized in terms of four axioms. One identifies outputs deserving index at most one. A second one establishes a strong monotonicity condition. A third one requires the index to satisfy a property of subadditivity. The last one consists of a monotonicity condition, for the h-index, and an aggregate monotonicity condition, for the g-index. 相似文献
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This paper reviews a number of studies comparing Thomson Scientific’s Web of Science (WoS) and Elsevier’s Scopus. It collates their journal coverage in an important medical subfield: oncology. It is found that all WoS-covered oncological journals (n = 126) are indexed in Scopus, but that Scopus covers many more journals (an additional n = 106). However, the latter group tends to have much lower impact factors than WoS covered journals. Among the top 25% of sources with the highest impact factors in Scopus, 94% is indexed in the WoS, and for the bottom 25% only 6%. In short, in oncology the WoS is a genuine subset of Scopus, and tends to cover the best journals from it in terms of citation impact per paper. Although Scopus covers 90% more oncological journals compared to WoS, the average Scopus-based impact factor for journals indexed by both databases is only 2.6% higher than that based on WoS data. Results reflect fundamental differences in coverage policies: the WoS based on Eugene Garfield’s concepts of covering a selective set of most frequently used (cited) journals; Scopus with broad coverage, more similar to large disciplinary literature databases. The paper also found that ‘classical’, WoS-based impact factors strongly correlate with a new, Scopus-based metric, SCImago Journal Rank (SJR), one of a series of new indicators founded on earlier work by Pinski and Narin [Pinski, G., & Narin F. (1976). Citation influence for journal aggregates of scientific publications: Theory, with application to the literature of physics. Information Processing and Management, 12, 297–312] that weight citations according to the prestige of the citing journal (Spearman’s rho = 0.93). Four lines of future research are proposed. 相似文献
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Research was undertaken that examined what, if any, correlation there was between the h-index and rankings by peer assessment, and what correlation there was between the 2008 UK RAE rankings and the collective h-index of submitting departments. About 100 international scholars in Library and Information Science were ranked by their peers on the quality of their work. These rankings were correlated with the h and g scores the scholars had achieved. The results showed that there was a correlation between their median rankings and the indexes. The 2008 RAE grade point averages (GPA) achieved by departments from three UoAs – Anthropology, Library and Information Management and Pharmacy were compared with each of their collective h and g index scores. Results were mixed, with a strong correlation between pharmacy departments and index scores, followed by library and information management to anthropology where negative and non-significant results were found. Taken together, the findings from the research indicate that individual ranking by peer assessment and their h-index or variants was generally good. Results for the RAE 2008 gave correlations between GPA and successive versions of the h-index which varied in strength, except for anthropology where, it is suggested detailed cited reference searches must be undertaken to maximise citation counts. 相似文献
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Michael Schreiber 《Journal of Informetrics》2010,4(4):647-651
The Hirsch index h and the g index proposed by Egghe as well as the f index and the t index proposed by Tol are shown to be special cases of a family of Hirsch index variants, based on the generalized mean with exponent p. Inequalities between the different indices are derived from the generalized mean inequality. The graphical determination of the indices is shown for one example. 相似文献
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Although a growing number of studies are examining the relationship between Internet use and political participation, varying study characteristics make the overall effect size difficult to estimate. Using a meta-analysis, we estimated the mean effect size and tested whether the effect size was influenced by study characteristics. Data for this meta-analysis were derived from 56 papers reporting 63 independent studies. Results revealed that Internet use had a weak relationship with political participation (rc?=?.22). Moderator analyses demonstrated that type of Internet use, Internet use measure, Internet use for news, type of political participation, sample origin, and survey year significantly moderated the relationship between Internet use and political participation. For instance, Internet use including news (rc?=?.27) had a significantly stronger relationship with political participation than did Internet use excluding news (rc?=?.19). European samples (rc?=?.27) had the largest mean correlation followed by North American samples (rc?=?.23) and Asian samples (rc?=?.18) in decreasing order of strength of relationship. The theoretical and methodological implications of the findings are discussed. 相似文献
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《Communication monographs》2012,79(3):286-310
Meta-analysis involves cumulating effects across studies in order to qualitatively summarize existing literatures. A recent finding suggests that the effect sizes reported in meta-analyses may be negatively correlated with study sample sizes. This prediction was tested with a sample of 51 published meta-analyses summarizing the results of 3,602 individual studies. The correlation between effect size and sample size was negative in almost 80 percent of the meta-analyses examined, and the negative correlation was not limited to a particular type of research or substantive area. This result most likely stems from a bias against publishing findings that are not statistically significant. The primary implication is that meta-analyses may systematically overestimate population effect sizes. It is recommended that researchers routinely examine the n–r scatter plot and correlation, or some other indication of publication bias and report this information in meta-analyses. 相似文献
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This study describes the meaning of and the formula for S-index, which is a novel evaluation index based on the number of citations of each article in a particular journal and the rank of the article according to the number of citations. This study compares S-index with Impact Factor (IF), which is the most well-known evaluation index, using the Korea Citation Index data. It is shown that S-index is positively correlated with the number of articles published in a journal. Tapered h-index (hT-index), which is based on all articles of a journal like S-index, is compared with S-index. It is shown that there is a very strong positive correlation between S-index and hT-index. Although S-index is similar to hT-index, S-index has a slightly better differentiating power and ranks the journal with evenly cited articles higher. 相似文献
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The h index is a widely used indicator to quantify an individual's scientific research output. But it has been criticized for its insufficient accuracy—the ability to discriminate reliably between meaningful amounts of research output. As a single measure it cannot capture the complete information on the citation distribution over a scientist's publication list. An extensive data set with bibliometric data on scientists working in the field of molecular biology is taken as an example to introduce two approaches providing additional information to the h index: (1) h2 lower, h2 center, and h2 upper are proposed, which allow quantification of three areas within a scientist's citation distribution: the low impact area (h2 lower), the area captured by the h index (h2 center), and the area of publications with the highest visibility (h2 upper). (2) Given the existence of different areas in the citation distribution, the segmented regression model (sRM) is proposed as a method to statistically estimate the number of papers in a scientist's publication list with the highest visibility. However, such sRM values should be compared across individuals with great care. 相似文献
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Harold C. RelyeaAuthor vitae 《Government Information Quarterly》2011,28(3):295-302
The Federal Register Act statutorily mandated an official gazette for the Federal Government to provide better accountability for administrative regulations, rules, and orders, and greater transparency in the creation of such law. The later establishment of the Code of Federal Regulations and the enactment of the Administrative Procedure Act added enhancement and incentives to the original act. The National Archives and Record Administration recently celebrated the seventy-fifth anniversary of this publication. The overview of the origins, development, and legacy of the Federal Register provided here was prepared as a background text for an invited lecture by the author at National Archives headquarters marking the creation of the Register and its heritage. 相似文献
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Antonio Quesada 《Journal of Informetrics》2009,3(2):158-160
The Hirsch index is a number that synthesizes a researcher's output. It is the maximum number h such that the researcher has h papers with at least h citations each. Woeginger [Woeginger, G. J. (2008a). An axiomatic characterization of the Hirsch-index. Mathematical Social Sciences, 56(2), 224–232; Woeginger, G. J. (2008b). A symmetry axiom for scientific impact indices. Journal of Informetrics, 2(3), 298–303] characterizes the Hirsch index when indices are assumed to be integer-valued. In this note, the Hirsch index is characterized, when indices are allowed to be real-valued, by adding to Woeginger's monotonicity two axioms in a way related to the concept of monotonicity. 相似文献
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The Annual Reports of the Commissioner of Indian Affairs, for the years 1824 through 1920, described the interactions between the American Indian tribes and the federal government. J. A. Jones (Jones, J. A. (1955). Key to the annual reports of the Commissioner of Indian Affairs. Ethnohistory, 2, 58–64). Provided a key to these documents found in the United States Congressional Serial Set, but this tool contained a number of errors. This article provides a fresh look at this key, with particular focus upon the availability of these materials through the Readex Serial Set digital collection. 相似文献