Enhanced View-Based Searching through the Decomposition of Dewey Decimal Classification Code

The scatter of items dealing with similar concepts through the physical library is a consequence of a classification process that produces a single notation to enable relative location. Compromises must be made to place an item where it is most appropriate for a given user community. No such compromise is needed with a digital library where the item can be considered to occupy a very large number of relative locations, as befits the needs of the user. Interfaces to these digital libraries can reuse the knowledge structures of their physical counterparts yet still address the problem of scatter. View-based searching is an approach that takes advantage of the knowledge structures but addresses the problem of scatter by applying a facetted approach to information retrieval. This paper describes the most recent developments in the implementation of a view-based searching system for a University Library OPAC. The user interface exploits the knowledge structures in the Dewey Decimal Classification Scheme (DOC) in navigable views with implicit Boolean searching. DDC classifies multifaceted items by building a single relative code from components. These codes may already have been combined in the schedules or be built according to well-documented instructions. Rules can be applied to decode these numbers to provide codes for each additional facet. To enhance the retrieval power of the view-based searching system, multiple facet codes are being extracted through decomposition from single Dewey Class Codes. This paper presents the results of applying automatic decomposition in respect of Geographic Area and the creation of a view (by Geographic Area) for the full collection of over 250,000 library items. This is the first step in demonstrating how the problem of scatter of subject matter across the disciplines of the Dewey Decimal Classification and the physical library collection can be addressed through the use of facets and view-based searching.