Hierarchical research
In a hierarchical search , the search in a documentation system is expanded from a descriptor to further descriptors that are subordinate or superordinate to this descriptor.
This assumes that the documentation language of the documentation system supports hierarchical relationships, as is the case with a classification and a thesaurus . The automatic extension of the search query to include further descriptors is also known as an explosion . In order to save computing time, frequent hierarchical searches can be carried out in advance and saved ( indexed ) as so-called pre-explosions . This is the case , for example, with medical subject headings . Whether and over how many levels hierarchical research makes sense in order to get a complete and delimited research result depends on the respective documentation system and the specific research.
example
A hierarchical system of terms contains the following descriptors, subordinate to each other:
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Atmung-
LungeBronchialsystemLungenbläschen
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During a normal search for Lunge, all documents that are indexed with a more general or specific descriptor will not be found. A hierarchical search can include the superordinate and subordinate descriptors and also finds documents that are not directly Lungeindexed.
A possible downwardly leading pre-explosion of the descriptor Atmungis calculated by additionally indexing all documents that are provided with descriptors below as pre-explosion of Atmung.
literature
- Wilhelm Gaus : Documentation and order theory. Information retrieval theory and practice . 5th revised edition. Springer, Berlin a. a. 2005, ISBN 3-540-23818-2 ( eXamen.press ).