The lognormal distribution explains the remarkable pattern documented by characteristic scores and scales in scientometrics     

Gabriel-Alexandru Vîiu 《Journal of Informetrics》2018,12(2):401-415

Characteristic scores and scales (CSS) – a well-established scientometric tool for the study of citation counts – have been used to document a striking phenomenon that characterizes citation distributions at high levels of aggregation: irrespective of scientific field and citation window empirical studies find a persistent pattern whereby about 70% of scientific papers belong to the class of poorly cited papers, about 21% belong to the class of fairly cited papers, 6% to that of remarkably cited papers and 3% to the class of outstandingly cited papers. This article aims to advance the understanding of this remarkable result by examining it in the context of the lognormal distribution, a popular model used to describe citation counts across scientific fields. The article shows that the application of the CSS method to lognormal distributions provides a very good fit to the 70–21–6–3% empirical pattern provided these distributions are characterized by a standard deviation parameter in the range of about 0.8–1.3. The CSS pattern is essentially explainable as an epiphenomenon of the lognormal functional form and, more generally, as a consequence of the skewness of science which is manifest in heavy-tailed citation distributions.  相似文献   

时标上一类神经网络的指数同步(英文)     

杜德军  陈安平 《湘南学院学报》2008,29(2):6-12

基于时标微积分学理论和Lyapunov泛函,我们得到了时标上一类神经网络指数同步的充分条件,这些条件在应用上容易用代数方法检验因而意义重大,我们的结果统一和推广一些连续神经网络和对应的离散情形的相关结论.  相似文献   

Making the Transition from Diagnosis to Treatment-planning: Validity,Reliability and Factor Structure of the Autism Spectrum Disorder Behaviour Checklist     

Vicki Bitsika 《International Journal of Disability, Development & Education》2018,65(1):22-32

The validity, reliability and factor structure of the Autism Spectrum Disorder Behaviour Checklist-Revised (ASDBC-R) were measured in a sample of 140 boys with Autism Spectrum Disorder (ASD) aged between 6 and 18 years. Internal consistency (Cronbach’s alpha) was satisfactory and the ASDBC-R significantly correlated with the Social Responsiveness Scale (SRS). Factor analysis of the ASDBC-R revealed a five-factor solution, which included all of the DSM-5 diagnostic criteria for ASD but with considerable overlap across criteria and factors. Agreement between ASDBC-R factors and SRS subscales was significant for three ASDBC-R factors but only marginal for the remaining two factors. Results indicated that the ASDBC-R could be used to develop targeted behavioural treatment plans for children with ASD across a range of settings, thus improving the development of individualised interventions for children with ASD.  相似文献