Statistical Aspects of the WEBSOM System in Organizing Document Collections
Samuel Kaski, Krista Lagus, Timo Honkela, Teuvo Kohonen · 1998
WEBSOM is a novel method for organizing document collections onto map displays to enhance the interactive browsing and retrieval of the documents. The map is organized automatically according to the contents of the full-text documents by the Self-Organizing Map algorithm. The map display provides a visual overview of the whole document collection. The overview, the map display, aids in the exploration since similar documents are located close to each other. In this paper we describe the WEBSOM system in a statistically oriented fashion and discuss its relations to other methods. Particular emphasis is put on how effective the methods are in treating large document collections. The two-phase architecture of the WEBSOM system makes it possible to build contextual information about the relations of words off-line into a word category representation, which can then be utilized rapidly on-line, when the documents are being encoded. The construction of large map displays from the encoded document representations is a computationally intensive operation when done in a straightforward manner. There exist, however, several effective computational shortcuts.