SP500207 Multilevel Ranking in Large Text Collections Using FAIRS chapter S-C. Chang H. Dediu H. Azzam M-W. Du National Institute of Standards and Technology Donna K. Harman 3. Considering more terms in the topics based on their popularity. 4. Using synonyms to expand terms. 5. Optimizing the ranking rules. This Will be important in Category A participation. The diversity of the docu- ments in Category A Will necessitate the use of opti- mum ranking rules which minimize the negative effects of extreme attribute values. These ranking rules will require more experimentation and analysis. 4.0 Conclusion Various techniques used by FAIRS to retrieve, weight and rank documents were discussed. The system was shown to successfully process the ThEC92 collection and achieve a high degree of precision and recall in the categories it par- ticipated, relative to other systems in those categories. The system was described, the ranking rules and weight- ing methods were also presented. The application of FAIRS to the TREC92 collection was analyzed in terms of system and retrieval performance. The retrieval perfor- mance was compared to competing systems in the same categories. It is hoped that further analysis of the results will provide insight into which features of FAIRS contrib- ute the most to its effectiveness. 5.0 References 1. Chang, S. C. and A. Chow, "Towards a Friendly Adaptable Information Retrieval System," Proceedings of R!AO 88, March 1988, pp.172-182. 2. Chang, S. C., "Adaptive Ranking: A Spreadsheet Approach." Technical Report TR00171288500, GTE Laboratories, Waltham, MA, Dec.1988. 3. Chow, A. and S. C. Chang, "Text Structure Specifica- tion: A Study to Eliminate File Conversion," Technical Note TN87500.03, GTE Laboratories, Waltharn, MA, Dec.1987. 4. Paice, C. D., J[OCRerr][OCRerr]ormation Retrievat and the Computer, MacDonald and Jane's Computer Monographs, Lon- don, 1977. 5. Du, M. W. and S. C. Chang, "A Model and Fast Algo- rithm for Multiple Errors Spelling Correction," Techni- cal Report TR06509895OO, GTE Laboratories, Waitham, MA, Sept.1989. 336