A Laplace Transfer-Based Citation Model and its Application in Detecting the Obsolescence Characteristics of Articles

This study describes a Laplace transfer-based citation model proposed for the actual citation process among journals. The actual citation process is a dynamic physical system which includes two continuous processes of ageing and publishing of cited articles. By deducing the Laplace transfer function for these two processes, we have established the input–output function for the actual citation process. Considering the subject of ‘automation and control systems’ as an example, time parameters associated with the ageing process were identified from the input–output function to examine the obsolescence characteristics for the subject. Experimental results show that the ageing time parameter calculated by the Laplace transferbased citation model is a good expression on the obsolescence of the field. The field shows a moderate ageing rate and a shortened obsolescence tendency on the whole. Most of the articles cited annually in this field are articles published 5–10 years ago. There is a monotonic decreasing dependence between the increment of IF and the increment of time parameter T₁, although IF always increases regardless of whether the ageing tends to prolong or shorten.