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1.
We show mathematically that the success-index can be any of the following impact indices, dependent on the value of the threshold used in the definition of the success-index: Hirsch-index (h-index), g-index, generalized Wu- and Kosmulski-indices, the average.  相似文献   

2.
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   

3.
Hirsch's h-index seeks to give a single number that in some sense summarizes an author's research output and its impact. Essentially, the h-index seeks to identify the most productive core of an author's output in terms of most received citations. This most productive set we refer to as the Hirsch core, or h-core. Jin's A-index relates to the average impact, as measured by the average number of citations, of this “most productive” core. In this paper, we investigate both the total productivity of the Hirsch core – what we term the size of the h-core – and the A-index using a previously proposed stochastic model for the publication/citation process, emphasising the importance of the dynamic, or time-dependent, nature of these measures. We also look at the inter-relationships between these measures. Numerical investigations suggest that the A-index is a linear function of time and of the h-index, while the size of the Hirsch core has an approximate square-law relationship with time, and hence also with the A-index and the h-index.  相似文献   

4.
We show that the h-index, g-index, ψ-index, and p-index, are related through the inequalities: h ≤ p ≤ g ≤ ψ. Moreover, this relation is proved theoretically in the mathematical framework of Lotkaian informetrics and is verified empirically by using two datasets from the Web of Science in the fields of electrochemistry and gerontology. For quantifying their relations, we estimate the g-index, ψ-index, and their cores and ratios of cores via a second-order Taylor series when the e-index, h-index, and C1 (the maximum number of citations received by a paper) are known. Then we find for the two empirical cases, that ratios of cores and average citations are approximately stable. Compared with the g-index, the offset-ability of the h-index decreases by 20% but the average citations increase by 20%. A similar observation holds for the comparison of the g-index and ψ-index. To explore the possible applications of cores of different indices, we apply them to extract the core structure of a network. The h-core is the most efficient, while the ψ-core includes more nodes with high betweenness.  相似文献   

5.
Starting from the notion of h-type indices for infinite sequences we investigate if these indices satisfy natural inequalities related to the arithmetic, the geometric and the harmonic mean. If f denotes an h-type index, such as the h- or the g-index, then we investigate inequalities such as min(f(X),f(Y)) ≤ f((X?+?Y)/2) ≤ max(f(X), f(Y)). We further investigate if: f(min(X,Y)) = min(f(X),f(Y)) and if f(max(X,Y)) = max(f(X),f(Y)). It is shown that the h-index satisfies all the equalities and inequalities we investigate but the g-index does not always, while it is always possible to find a counterexample involving the R-index. This shows that the h-index enjoys a number of interesting mathematical properties as an operator in the partially ordered positive cone (R+)∞ of all infinite sequences with non-negative real values.In a second part we consider decreasing vectors X and Y with components at most at distance d. Denoting by D the constant sequence (d,d,d, …) and by Y-D the vector (max(yr-d), 0)r, we prove that under certain natural conditions, the double inequality h(Y-D) ≤ h(X) ≤ h(Y?+?D) holds.  相似文献   

6.
This paper analyzes several well-known bibliometric indices using an axiomatic approach. We concentrate on indices aiming at capturing the global impact of a scientific output and do not investigate indices aiming at capturing an average impact. Hence, the indices that we study are designed to evaluate authors or groups of authors but not journals. The bibliometric indices that are studied include classic ones such as the number of highly cited papers as well as more recent ones such as the h-index and the g-index. We give conditions that characterize these indices, up to the multiplication by a positive constant. We also study the bibliometric rankings that are induced by these indices. Hence, we provide a general framework for the comparison of bibliometric rankings and indices.  相似文献   

7.
This article highlights the importance of using polar coordinates when studying functions, in particular in relation to generalized h-type indices. Concretely, generalized h-type indices are essentially polar coordinates. This observation ties informetric ideas to standard mathematics. This article is essentially meant to provide tools for further studies.  相似文献   

8.
Plagiarism is one of the most common research misconducts and has many negative consequences. It can potentially destroy the reputation of an institution. Only a few studies have explored plagiarism in Saudi Arabia, and these have focused on academic institutions. Therefore, in this study, we investigated the attitudes of researchers towards plagiarism at a tertiary care hospital in Riyadh, Saudi Arabia, using the established Attitudes Towards Plagiarism questionnaire. The questionnaire contains demographic data along with 29 statements divided into three sections: positive attitude towards plagiarism, which reflects the approval and acceptance of plagiarism (12 items); negative attitude towards plagiarism, which reflects deprecation and condemnation of plagiarism (7 items); and subjective norms towards plagiarism, which reflects personal perception of the extent and acceptance of plagiarism in society (10 items). Responses were collected from 237 participants. The overall attitudes of researchers showed a disapproval for plagiarism in medical research but also revealed some ambiguity about self‐plagiarism and a belief that others were more likely to plagiarize than the respondent. Our findings suggest that awareness about different forms of plagiarism among researchers should be increased. We recommend that researchers' attitudes towards plagiarism should be investigated further in a rigorous association study.  相似文献   

9.
Collaborative Filtering (CF) Systems have been studied extensively for more than a decade to confront the “information overload” problem. Nearest-neighbor CF is based either on similarities between users or between items, to form a neighborhood of users or items, respectively. Recent research has tried to combine the two aforementioned approaches to improve effectiveness. Traditional clustering approaches (k-means or hierarchical clustering) has been also used to speed up the recommendation process. In this paper, we use biclustering to disclose this duality between users and items, by grouping them in both dimensions simultaneously. We propose a novel nearest-biclusters algorithm, which uses a new similarity measure that achieves partial matching of users’ preferences. We apply nearest-biclusters in combination with two different types of biclustering algorithms—Bimax and xMotif—for constant and coherent biclustering, respectively. Extensive performance evaluation results in three real-life data sets are provided, which show that the proposed method improves substantially the performance of the CF process.
Yannis ManolopoulosEmail:
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10.
Are you in h?     
A new method of assessment of scientific papers, scientists, and scientific institutions was defined. The significance of a paper was assessed by the definition of the largest (the most prestigious) set, including that paper in its h-core. The sets of papers were defined by affiliation (country, city, university, department) or by subject (branches and sub-branches of science, journal). The inclusion of a paper in the h-core of certain set(s) was used as an indicator of the significance of that paper, and of the scientific output of its author(s), of their scientific institution(s), etc. An analogous procedure was used to assess the contribution of an individual to the scientific output of his/her scientific institution, branch of science, etc.  相似文献   

11.
A compressed full-text self-index for a text T, of size u, is a data structure used to search for patterns P, of size m, in T, that requires reduced space, i.e. space that depends on the empirical entropy (H k or H 0) of T, and is, furthermore, able to reproduce any substring of T. In this paper we present a new compressed self-index able to locate the occurrences of P in O((m + occ)log u) time, where occ is the number of occurrences. The fundamental improvement over previous LZ78 based indexes is the reduction of the search time dependency on m from O(m 2) to O(m). To achieve this result we point out the main obstacle to linear time algorithms based on LZ78 data compression and expose and explore the nature of a recurrent structure in LZ-indexes, the suffix tree. We show that our method is very competitive in practice by comparing it against other state of the art compressed indexes.
Arlindo L. OliveiraEmail:
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12.
The Center for Science and Technology Studies at Leiden University advocates the use of specific normalizations for assessing research performance with reference to a world average. The Journal Citation Score (JCS) and Field Citation Score (FCS) are averaged for the research group or individual researcher under study, and then these values are used as denominators of the (mean) Citations per publication (CPP). Thus, this normalization is based on dividing two averages. This procedure only generates a legitimate indicator in the case of underlying normal distributions. Given the skewed distributions under study, one should average the observed versus expected values which are to be divided first for each publication. We show the effects of the Leiden normalization for a recent evaluation where we happened to have access to the underlying data.  相似文献   

13.
The citation records of 26 physicists are analyzed in order to determine the modified g index gm which takes multiple coauthorship into account by fractionalized counting of the publications. The results are compared with the original g index as well as with the h index and the respective modified h index hm. Although the correlations between these indices are relatively strong, the arrangement of the datasets is significantly different in detail depending on whether they are put into order according to the values of either the original or the modified indices.  相似文献   

14.
ABSTRACT

Offering quality services and evaluating the rate of success in providing users with target services is the pervasive importance of academic libraries. The central purpose of this study is to determine key dimensions of service quality and satisfaction through developing a new item-scale for evaluating service quality and satisfaction in academic libraries. For primary data collection the study used a 28-item instrument based on five dimensional modified version of SERVQUAL. Respondents were asked to indicate their degree of opinions in the three-columns format: desired service expectation, minimum service expectation, and perception of service performance on a 7-point Likert-type scale. The researcher initially conducted a pilot survey to clarify the overall structure of the questionnaire items to be accepted and used. The reliability of the analysis of data with distinct service attributes were taken from ten public and private university libraries in Bangladesh. Subjecting data obtained to exploratory factor analysis shows that academic library service quality and satisfaction is related to four basic dimensions: caring, competence, resources, and library as a place. Twenty-six service items were identified after extraction through exploratory factor analysis, where nine items were shown before “caring,” five items for “competence,” seven items for “resources,” and five items for “library as a place.” The result in fact provides a generic and robust instrument and recognizes a new item-scale, namely “real service expectation” for the librarians and information science practitioners in the assessment of service quality and satisfaction in academic libraries and in the related fields.  相似文献   

15.
《Journal of Informetrics》2019,13(3):785-792
In this article we solve a minimum problem involving step functions. The solution of this problem leads to an investigation into generalized h- and g-indices. This minimum problem and the related generalized h- and g-indices are studied in a general context of decreasing differentiable functions as well as in the specific case of Lotkaian informetrics. The study illustrates the use of h-and g-indices and their generalizations in a context which bears no relation to the research evaluation context in which these indices were originally introduced.  相似文献   

16.
To explore the citation evolution of papers published in the same year but different month, we selected papers from a discipline (physical geography), a subject (diabetes: endocrine and metabolism) and a journal (Journal of Biological Chemistry) published in 2005 as research objects. These papers were divided into six groups according to the difference in publication month, and we analyzed citations to these papers for the 9 years after publication. The results showed that within 5 years after papers from physical geography were published, the overall differences in citations of papers in different groups were statistically significant (P < 0.05); after that, the differences were not statistically significant. Within 5 years after papers from diabetes (endocrine and metabolism) were published, the overall differences in citations of papers in different groups were statistically significant (P < 0.05); thereafter, the differences were not statistically significant. Within 7 years after papers from the Journal of Biological Chemistry were published, the overall differences in citations of papers in different groups were statistically significant (P < 0.05); thereafter, the differences were not statistically significant. Citations of papers followed the same pattern irrespective of discipline, subject or journal: citations of papers published in the same year but different month were obviously different in the first few publishing years, but as time went on, only the difference in publication month in a calendar year did not affect the papers' longer‐term citation.  相似文献   

17.
《Journal of Informetrics》2019,13(2):515-539
Counting of number of papers, of citations and the h-index are the simplest bibliometric indices of the impact of research. We discuss some improvements. First, we replace citations with individual citations, fractionally shared among co-authors, to take into account that different papers and different fields have largely different average number of co-authors and of references. Next, we improve on citation counting applying the PageRank algorithm to citations among papers. Being time-ordered, this reduces to a weighted counting of citation descendants that we call PaperRank. We compute a related AuthorRank applying the PageRank algorithm to citations among authors. These metrics quantify the impact of an author or paper taking into account the impact of those authors that cite it. Finally, we show how self- and circular-citations can be eliminated by defining a closed market of Citation-coins. We apply these metrics to the InSpire database that covers fundamental physics, presenting results for papers, authors, journals, institutes, towns, countries for all-time and in recent time periods.  相似文献   

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