Mapping Science - Mapping Scientific Frontiers: The Quest for Knowledge Visualization - page 297

Fig. 8.15 69 clusters formed by 706 sentences that cited the 1998 Wakefield paper

Fig. 8.16 Divergent topics in a topic-transition visualization of the 1998 Wakefield et al. article

citations to the retracted article. The topic-flow visualization was constructed as
follows. First, we group the citation sentences into groups defined by their publica-
tion time. Citation sentences made in each year are clustered into topics. Similarities
between topics in adjacent years are computed in terms of the overlapping topic
terms between them. Topic flows connect topics in adjacent years that meet a user
defined similarity threshold (See Fig. 8.16 ).
Each topic in the flow map can be characterized as convergent and divergent
topics as well as steady topics. A convergent topic in a particular year is defined