Filters, Webs and Answers: The University of Iowa TREC-8 Results.
Elena Catona, David A. Eichmann, Padmini Srinivasan · Text REtrieval Conference · 1999
Our approach to filtering involves a two-level dynamic clustering technique. Each filtering topic is used to create a primary cluster that forms a general profile for the topic. Documents that are attracted into a primary cluster participate in a topic-specific second level clustering process yielding what we refer to as secondary clusters. These secondary clusters, depending upon their status, are responsible for declaring, i.e., retrieving, documents for the topic.