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 PHRASES, WEIGHT 1.0 o THESAURUS-3 0 [OCRerr]e PHRASES, WEIGHT 1.0 THESAURUS-I 0 [OCRerr]e PHRASES, WEIGHT 1.0 ISION PRECISION PRECISION 1.0 I.C 0.8 - 0.6 - 0£ - 0.6 - 0.4 - OA - 0.2- 0.2 - I I I I 1[OCRerr][OCRerr][OCRerr]AIE I I I I I I I I 1[OCRerr]REC[OCRerr] 0.2 0.4 0.6 0.8 [OCRerr] 0.2 0.4 0.6 0.8 1.0 1[OCRerr][OCRerr][OCRerr]ALL0 0.2 Q4 0.6 0.8 1.0 RE-3, Abstracts, 34 Requests Cran-l, Abstracts, 42 Requests ADI, Full Text, 35 Requests Performance Curves Coitparing Thesaurus and Phrase Dictionaries on Three Collections Fig. 21