• Temporal Evolution of Bradford Curves in Specialized Library Contexts

    分类: 图书馆学、情报学 >> 情报学 提交时间: 2024-05-23

    摘要: The Bradford’s law of bibliographic scattering is a fundamental law in bibliometrics and can provide valuable guidance to academic libraries in literature search and procurement. However, the Bradford’s curves can take various shapes at different time points and there is still a lack of causal explanation for it, so the prediction of its shape is still an open question. This paper attributes the deviation of Bradford curve from the theoretical J-shape to the integer constraints of the journal number and article number, and extends the Leimkuhler and Egghe’s formula to cover the core region of very productive journals, where the theoretical journal number of which fall below one, ftXi=CXiα . The key parameters of the extended formula are identified and studied by using the Simon-Yule model. The reasons for the Groos Droop are explained and the critical point for the shape change are studied. Finally, the proposed formulae are validated with the empirical data found in the literature. It is found that the proposed method can be used to predict the evolution of Bradford’s curves and thus guide the academic library for scientific literature procurement and utilization.

  • Analysis of effects to scientific impact indicators based on the coevolution of coauthorship and citation networks

    分类: 图书馆学、情报学 >> 情报学 提交时间: 2024-04-19

    摘要: While computer modeling and simulation are crucial for understanding scientometrics, their practical use in literature remains somewhat limited. In this study, we establish a joint coauthorship and citation network using preferential attachment. As papers get published, we update the coauthorship network based on each paper’s author list, representing the collaborative team behind it. This team is formed considering the number of collaborations each author has, and we introduce new authors at a fixed probability, expanding the coauthorship network. Simultaneously, as each paper cites a specific number of references, we add an equivalent number of citations to the citation network upon publication. The likelihood of a paper being cited depends on its existing citations, fitness value, and age. Then we calculate the journal impact factor and h -index, using them as examples of scientific impact indicators. After thorough validation, we conduct case studies to analyze the impact of different parameters on the journal impact factor and h -index. The findings reveal that increasing the reference number N or reducing the paper’s lifetime θ significantly boosts the journal impact factor and average h -index. On the other hand, enlarging the team size m without introducing new authors or decreasing the probability of newcomers p notably increases the average h -index. In conclusion, it is evident that various parameters influence scientific impact indicators, and their interpretation can be manipulated by authors. Thus, exploring the impact of these parameters and continually refining scientific impact indicators are essential. The modeling and simulation method serves as a powerful tool in this ongoing process, and the model can be easily extended to include other scientific impact indicators and scenarios.