COMPUTER SEARCHING OF UDC NUMBERS

The Universal Decimal Classification (UDC) is able to provide a detailed description of the subject content of a document in any area. Its hierarchical and synthetic structure, which is generally reflected in its notation, should enable computer searching for hierarchically‐related subjects and for the individual facets of a complex subject. The possibilities of using these features in automated retrieval are discussed, and attention is drawn to places where the UDC falls short. A number of online catalogues, databases, and information retrieval packages are discussed in terms of their ability to allow searching on UDC numbers. The most sophisticated ones, such as ETHICS at the ETH Library, use a separate file of verbal descriptors linked to the document file through UDC numbers. Suggestions are made for enhancing retrieval performance on UDC numbers in simple systems, and for ways in which the classification might be developed to improve automated searching.