ISR11 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-30 15 Documents 8 Documents Returned Returned Initial Ranking of Relevant Documents 3, 12, 17, 33, 44 3, 12, 17, 33, 44 Ranking After First Update 1, 2, 3, 15, 30 1, 3, 10, 30, 34 Ranking After Second' Update 1, 2, 3, 4, 19 1, 2, 11, 12, 29 Ranking After Third Update 1, 2, 3, 4, 19 1, 2, 11, 13, 30 [OCRerr]Llery [OCRerr]A10GR0UP Cosine Correlation Function Increasing Alpha Strategy Ranks of Relevant Documents After Each Update as a Function of the Nun[OCRerr]er of Documents Returned in Answer to a Query Figure 1 Ranks of Relevant Normalized Normalized Rank Log Documents Recall Precision Recall Precision Initial Results 1,2,19,27 .877 .739 .204 .458 Results After First Update 1,2, 6,33 .899 .805 .238 .531 Results After Second Update 1,2, 3,21 .946 .88[OCRerr] 370 .657 Results After Third Update 1,2, 3,18 .956 .895 .417 .679 Cuery [OCRerr]l0CHEMIST Cosine Correlation Function Increasing Alpha Strategy Typical Results of [OCRerr][OCRerr]ery Modification Using Relevance Feedback Information in the Case when the Relevant Documents are in One Region of [OCRerr]-Space Figure 2