ISR11 Scientific Report No. ISR-11 Information Storage and Retrieval Relevance Feedback in an Information Retrieval System chapter W. Riddle T. Horwitz R. Dietz Harvard University Gerard Salton Use, reproduction, or publication, in whole or in part, is permitted for any purpose of the United States Government. vi-143 Relevant Document Normalized Normalized Ranks Recall Precision A. Ou,ery OA9ANALYSIS Initial Results 33,50 .506 .172 Results After First Update 6,28 .506 [OCRerr] Results After Second Update 1,2 1.000 1.000 B. Query OBIIINDEX Initial Results 21 .756 .309 Results After First Update 4'4 .[OCRerr]76 .141 Results After Second Update 41 .512 .157 Results After Third Update 22 .744 .299 C. Ouery QB8COSTRET Initial Results 16 .817 .371 Results After First Update 65 .220 .053 Results After Second Update 37 .561 181 Results After Third Update 7 .927 .558 Cosine Correlation Function and Increasing Alpha Strategy used for all Three Cases Selected Results Showing Various Effects of the Negative Weighting Heuristic Method Figure 9