SP500215 UCLA-Okapi at TREC-2: Query Expansion Experiments chapter E. Efthimiadis P. Biron National Institute of Standards and Technology D. K. Harman Acknowledgements Thanks to Stephen Robertson and Stephen Walker for making OKAPI available to UCLA. We are especially thankful to Stephen Walker for all his con- tinuing help over and above that indicated in the text. We wish to thank Donna Harman of NIST for her support during TREC-2. This research was supported by a UCLA Academic Senate grant that also provided financial support for the graduate re- search assistantship of PVB. Finally, ENE is grateful to SUN Microsystems Inc. for the equipment grant of the SPARC 2 that made this research p05- sible. References Efthimiadis, E.N. (1993a) A user-centered evaluation of rank- ing algorithms for interactive query expansion. In: Korfhage R., Rasmussen E. and Willett P. (eds.) Proceedings of the 16th International Conference of the Association of Comput- ing Machinery, Specialist Interest Group in Information Re- trieval, June 1993. Pittsburgh, PA: ACM Press. pp.146-159. Efthimiadis, E.N. (in press) `User choices: As the yardstick for the evaluation of ranking algorithms for interactive query ex- pansion.' Information Processing [OCRerr] Management. In press. Efthimiadis, E.N. `Interactive Query Expansion: A User- based evaluation in a Relevance Feedback Environment.' Manuscript submitted for publication. Harper, D.J. & van Rijsbergen, C.J. (1978) An evaluation of feedback in document retrieval using co-occurrence data. Journal of Documentation, 34(3), 189-216. Porter, M.F. & Galpin, V. (1988) Relevance feedback in a public access catalogue for a research library: Muscat at the Scott Polar Research Institute. Program, 22(1), 1-20. Robertson, S.E. (1990) On term selection for query expansion. Journal of Documentation, 46(4), 359-364. Robertson, S.E. and Sparck Jones, K. (1976) Relevance weight- ing of search terms. Journal of the American Society for In- formation Science, 27(3), 129-146. Robertson, S.E., Walker, S., Hancock-Beaulieu, M., Gull, A. & Lau, M. (1993a) Okapi at TREC. In: Harman, D. K. (Ed.) The First Text Retrieval Conference (TREC-1). Proceedings. NIST Special Publication 500-207. Gaithersburg, MD: NIST, 1993. pp2l-30. Robertson, S.E., Walker, S., Jones, S., Hancock-Beaulieu, M., & Gatford, M. (1993b) Okapi at TREC-2. In: Harman, D.K. (Ed.) Text Retrieval Conference (TREC-2). Galthersburg, MD: NIST, August 30-September 1, 1993, Proceedings, to appear. 289 van Rusbergen, C.J. (1977) A theoretical basis for the use of co-occurrence data in information retrieval. Journal of Doc- umentation, 33, 106-119. van Rijsbergen, C.J., Harper, D.J. & Porter, M.F. (1981) The selection of good search terms. Information Processing and Management, 17(2), 77-91. A Runs The runs presented here are grouped by algorithm used for the expansion. The list starts with runs that did not include query expansion. bmlS.phn.qen.uclagsln bmlS.phn.qen.uclagsly bmlS.phy.qen.uclagsly bmlS.phb.qen.uclagsly bmlS.phb.qey:wpq-10-5.uclagsln bmlS.phb.qey:wpq-10-5.uclagsly bmlS.phb.qey:wpq-10-10.uclagsln bmlS.phb.qey:wpq-10-10.uclagsly bmlS.phb.qey:wpq-10-15.uclagsln bmlS.phb.qey:wpq-20-5.uclagsln bmlS.phb.qey:wpq-20-10.uclagsln bmls.phb.qey:wpq-20-15.uclagsln bmlS.phb.qey:wpq-30-5.uclagsln bmlS.phb.qey:wpq-30-10.uclagsln bmlS.phb.qey:wpq-30-15.uclagsln bmlS.phb.qey:emim-10-10.uclagsln bmlS.phb.qey:emim-10-10.uclagsly bmlS.phb.qey:emim-20-10.uclagsly bmlS.phb.qey:emim-30-10.uclagsly bmlS.phb.qey:port-10-10.uclagsln bmlS.phb.qey:port-10-10.uclagsly bmlS.phb.qey:port-20-10.uclagsly bmlS.phb.qey:port-30-10.uclagsly bm15.phb.qey:r~hi1o-10-10.uclagsln bm15.phb.qey:r~hilo-10-10.uclagsly bmlS.phb.qey r lohi 10 5.uclagsln bmlS.phb.qey r lohi 10 10.uclagsln bmlS.phb.qey r lohi 10 10.uclagsly bmlS.phb.qey r lohi 10 15.uclagsln bmlS.phb.qey r lohi 20 5.uclagslu bmlS.phb.qey r lohi 20 l0.uclagsln bmlS.phb.qey.rAohi 20 15.uclagsln bmlS.phb.qey:rAohi-30-5.uclagsln bmlS.phb.qey:rAohi-30-10.uclagsln bm15.phb.qey:r~lohi-30-15.uclagsln