IRS13 Thesaurus, Phrase and Hierarchy Dictionaries chapter E. M. Keen Harvard University Gerard Salton Use, reproduction, or publication, in whole or in part, is permitted for any purpose of the United States Government. o THESAURUS-3 0 [OCRerr] HIERARCHY-PARENTS A7 o THESAURUS-3 7 0 [OCRerr] HIERARCHY-SONS [OCRerr]RECISI0N PRECISION 1.0 - 1.0 - 0.8 - 0.6 - 0.6 - 0.6 - [OCRerr]A[OCRerr]0 OA - 04 - 0.2 - 0.2 - I I I I I RECALL 0 0.2 0.4 0.6 0.8 1.0 a) Hierarchy Expansion by Parents I I I I I 0 0.2 0.4 0.6 0.8 1.0 RECALL b) Hierarchy Expansion by Sons Performance Curves Comparing Thesaurus with Two Hierarchy Searches, IRE-3 Collection Fig. 22