The influence of author self-citations on bibliometric macro indicators

In a recent paper the authors have studied the role of author self-citations within the process of documented scientific communication. Two important regularities such as the relative fast ageing of self-citations with respect to foreign citations and the “square-root law” characterising the conditional expectation of self-citations for given number of foreign citation have been found studying the phenomenon of author self-citations at the macro level. The goal of the present paper is to study the effect of author self-citations on macro indicators. The analysis of citation based indicators for 15 fields in the sciences, social sciences and humanities substantiates that at this level of aggregation there is no need for any revision of national indicators and the underlying journal citation measures in the context of excluding self-citations. This revised version was published online in June 2006 with corrections to the Cover Date.     

The influence of author self-citations on bibliometric meso-indicators. The case of european universities

Summary In earlier studies by the authors, basic regularities of author self-citations have been analysed. These regularities are related to the ageing, to the relation between self-citations and foreign citations, to the interdependence of self-citations with other bibliometric indicators and to the influence of co-authorship on self-citation behaviour. Although both national and subject specific peculiarities influence the share of self-citations at the macro level, the authors came to the conclusion that - at this level of aggregation - there is practically no need for excluding self-citations. The aim of the present study is to answer the question in how far the influence of author self-citations on bibliometric meso-indicators deviates from that at the macro level, and to what extent national reference standards can be used in bibliometric meso analyses. In order to study the situation at the institutional level, a selection of twelve European universities representing different countries and different research profiles have been made. The results show a quite complex situation at the meso-level, therefore we suggest the usage of both indicators, including and excluding self-citations.     

A simple back-of-the-envelope test for self-citations using Google Scholar author profiles

Scientometrics - The issue of self-citation has received much attention in academia. Widely used and accessible tools such as Google Scholar do not provide information about self-citations....     

Scientific impact of an author and role of self-citations

Scientometrics - In bibliometric and scientometric research, the quantitative assessment of scientific impact has boomed over the past few decades. Citations, being playing a major role in...     

The other side of the coin: The intricacies of author self-citations

The present study views author self-citations, as a blend of experience and cognition of authors. This paper supports to lay down emphasis on consciousness and cognition of authors while assessing author self-citations. This revised version was published online in June 2006 with corrections to the Cover Date.     

The relationship between co-authorship,currency of references and author self-citations

This paper attempts to identify the relationship between co-authorship and the currency of the references and author self-citations in the key journals of environmental engineering. The results show that the self-citation rate of co-authored articles is higher than in single-authored articles. A statistically significant correlation is identified between the numbers of co-authors, the rate of author self-citing and the author self-cited; though it was a low correlation. The value of coefficient correlation between the number of co-authors and the author self-citing rate is slightly higher than that between the number of co-authors and the author self-cited rate, which indicates that the number of co-authors hold a stronger correlation with the self-citing rate than the self-cited rate. Meanwhile, self-citing references are found to be more up-to-date than references to others. The range of publication years of self-citing references is smaller than that of references to others, indicating that researchers tend to preferentially cite their own recent works. There is no significant difference in the latest references between self-citing references and the references to others. It might result from electronic journals that provide an easy access to the most current publications.     

To cite or not to cite: author self-citations and the impact factor

Author self-citations are another factor that affects the impact factor of a journal. Typically these self-citations are just counted as such. But to be more meaningful I suggest that when examining the contribution of authors?? self-citations to impact factors one should first count the number of citations in the text rather than in the reference list, and then discriminate between different kinds of author self-citations??from those that are informative to those that are self-enhancing??if these data are to be more credible.     

A concise review on the role of author self-citations in information science, bibliometrics and science policy

Summary  The objective of the present study is twofold: (1) to show the aims and means of quantitative interpretation of bibliographic features in bibliometrics and their re-interpretation in research policy, and (2) to summarise the state-of-art in self-citation research. The authors describe three approaches to the role of author self-citations and possible conflicts arising from the different perspectives. From the bibliometric viewpoint we can conclude that that there is no reason for condemning self-citations in general or for removing them from macro or meso statistics; supplementary indicators based on self-citations are, nonetheless, useful to understand communication patterns.     

A macro study of self-citation

This study investigates the role of self-citation in the scientific production of Norway (1981-1996). More than 45,000 publications have been analysed. Using a three-year citation window we find that 36% of all citations represent author self-citations. However, this percentage is decreasing when citations are traced for longer periods. We find the highest share of self-citation among the least cited papers. There is a strong positive correlation between the number of self-citations and the number of authors of the publications. Still, only a minor part of the overall increase in citation rates that can be found for multi-authored papers is due to self-citations. Also, the share of self-citation shows significant variations among different scientific disciplines. The results are relevant for the discussion concerning use of citation indicators in research assessments. This revised version was published online in August 2006 with corrections to the Cover Date.     

The efficiency of self-citations in economics

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.     

A dual refinement of journal self-citation measures

Journal self-citation is one of the crucial bibliometric indicators, which measures the contribution of a journal towards a speciality. Journal self-citation rate is normalised by adapting a two stage refinement. The normalised self-citing rates are compared with external cited rate to know the self and external influence of journals.     

A CAD approach to the minimum weight design problem

A structure is defined by a set of governing points. These points can be used to define lines, surfaces and solids. A governing point can be connected to a design variable. The values of the design variables are determined in order to minimize the weight of the structure subject to a number of stress constraints. Three simple structures are then designed.     

A fractional filter-based beamformer architecture using postfiltering approach to minimize hardware complexity

A novel beamformer architecture using fractional delay filters is proposed and verified through experiments. By performing interchannel summation prior to filtering operation in the manner producing no error, the proposed architecture requires only three four-tap filters for the whole beamformer and four simple demultiplexers per each channel.     

Stochastic dynamics of nonlinear systems with a fractional power-law nonlinear term: The fractional calculus approach

Fractional power-law nonlinear drift arises in many applications of engineering interest, as in structures with nonlinear fluid viscous-elastic dampers. The probabilistic characterization of such structures under external Gaussian white noise excitation is still an open problem.This paper addresses the solution of such a nonlinear system providing the equation governing the evolution of the characteristic function, which involves the Riesz fractional operator. An efficient numerical procedure to handle the problem is also proposed.     

一种通过优化链路权值来增强网络生存性的方案

提出了一种通过优化链路权值来增强网络生存性的方案.该方案在选择链路权值时考虑了所有可能的链路故障情景和网络流量的变化,通过引入费用函数对过载链路赋以高费用的方法来避免链路过载,并利用遗传算法在所有可能的链路权值组合中寻找使链路费用之和最小的组合.实验结果表明通过该方案求得的权值组合,能够使网络在出现流量变化和链路故障时有效避免链路拥塞,从而增强网络的生存性.     

A knowledge graph embeddings based approach for author name disambiguation using literals

Scientometrics - Scholarly data is growing continuously containing information about the articles from a plethora of venues including conferences, journals, etc. Many initiatives have been taken to...     

Quantitative dosing of surfaces with fluorescent molecules: characterization of fractional monolayer coverages by counting single molecules.

Quantitative deposition of dye molecules onto a substrate has been achieved at very low surface concentrations, in the range of 5 x 10(-8) - 1 x 10(-6) monolayer, using the technique of controlled substrate withdrawal from solution. These small surface populations were determined with high (>96%) efficiency by single-molecule counting using an epi-illumination, fluorescence microscope with charge-coupled device detector. The fluorescence imaging resolution (3sigma) is 0.78 microm; over a uniform excitation area of 67 x 67 microm2, a large number (>7,500) of spatially resolved channels are available for counting individual molecules. At low coverages, the number density of fluorescence spots on the surface agrees with the expected surface concentration of molecules, based on the concentration of dye in solution and the solution film thickness predicted from theory. When the surface density of molecules is high enough that fluorescence spot overlap is likely to occur within the optical resolution of the instrument, the observed fewer number of spots can be corrected for overlap through a site occupation model based on Poisson statistics.     

Mechanics of light weight proppants: A discrete approach

The computational and experimental assessment of light-weight proppants are undertaken to identify their effectiveness and efficiency to replace sand enlisted in hydraulic fracturing treatments in oil or gas well operations. A mixture of ground-nut-shells, aluminum or ceramic particles are shown to reduce the viscosity of the fracturing fluid while increasing its resistance to compression. Herein explicit dynamic finite element method is implemented to study quasi-static compression of a proppant pack where each granule (particle) is modeled individually. Various mixtures of hard and soft particles are investigated as a function of shape, size and inter-particle friction. The particle interactions clearly illustrate changes in pore space as a function of pressure, mixture composition and friction. The pressure vs displacement response of a proppant pack reflects strong dependence on mixture composition and initial particle configuration and has been compared with the test data. Friction leads to higher porosity by limiting particle rearrangement. Models reveal that softer rock with a mixture of hard and soft particles inhibit flowback but may decrease the pack permeability.     

A comparative study of first and all-author co-citation counting,and two different matrix generation approaches applied for author co-citation analyses

Aim  The present article contributes to the current methodological debate concerning author co-citation analyses. (ACA) The study compares two different units of analyses, i.e. first- versus inclusive all-author co-citation counting, as well as two different matrix generation approaches, i.e. a conventional multivariate and the so-called Drexel approach, in order to investigate their influence upon mapping results. The aim of the present study is therefore to provide more methodological awareness and empirical evidence concerning author co-citation studies. Method  The study is based on structured XML documents extracted from the IEEE collection. These data allow the construction of ad-hoc citation indexes, which enables us to carry out the hitherto largest all-author co-citation study. Four ACA are made, combining the different units of analyses with the different matrix generation approaches. The results are evaluated quantitatively by means of multidimensional scaling, factor analysis, Procrustes and Mantel statistics. Results  The results show that the inclusion of all cited authors can provide a better fit of data in two-dimensional mappings based on MDS, and that inclusive all-author co-citation counting may lead to stronger groupings in the maps. Further, the two matrix generation approaches produce maps that have some resemblances, but also many differences at the more detailed levels. The Drexel approach produces results that have noticeably lower stress values and are more concentrated into groupings. Finally, the study also demonstrates the importance of sparse matrices and their potential problems in connection with factor analysis. Conclusion  We can confirm that inclusive all-ACA produce more coherent groupings of authors, whereas the present study cannot clearly confirm previous findings that first-ACA identifies more specialties, though some vague indication is given. Most crucially, strong evidence is given to the determining effect that matrix generation approaches have on the mapping of author co-citation data and thus the interpretation of such maps. Evidence is provided for the seemingly advantages of the Drexel approach.