The Structure and Dynamics of Scientific Knowledge - Mapping Scientific Frontiers: The Quest for Knowledge Visualization - page 176

Fig. 5.8 Zooming in even further to examine the structure of immunology (Reproduced from
Garfield 1998 )
narrative trails when we retrace the possible sequence of thought by following trails
of co-citation links. TSP is a hard problem to solve. Luckily, there are some very
efficient algorithms to traverse a network, namely breath-first search (BFS) and
depth-first search (DFS). Both result in a minimum-spanning tree (MST). Small
considered several possible heuristics for the traversal in his study. For example,
when we survey the literature, we tend to start with some old articles so as to form
a historical context. A reasonable approach is to start from the oldest article in
the co-citation network. In this example, DFS was used to generate an MST. The
longest path through the MST tree was chosen as the main sequence of the specialty
narrative (See Fig. 5.9 ).
The context of citing provides first-hand information on the nature of citation.
A specialty narrative is only meaningful and tangible if sufficient contextual
information of citation is attached to the narrative. The citation context of a given
article consists of sentences that explicitly cite the article. Such sentences may come
from different citing articles. Different authors may cite the same article for different
reasons. On the other hand, researchers may cite several articles within one sentence.
Small took all these circumstances into account in his study. In the foreseeable
future, we will still have to rely on human intervention to make such selection,
as opposed to automated algorithmic devices. Nevertheless, NEC's ResearchIndex
has shown some promising signs of how much we might benefit from citation
contexts automatically extracted from documents on the Web. In his 1986 specialty
narrative study, Small had to examine passages from citing papers, coded them, and