SP500207 TIPSTER Panel -- The University of Massachusetts TIPSTER Project chapter W. B. Croft National Institute of Standards and Technology Donna K. Harman Query Type Average Precision in Top Ten (30 queries) Character-Based Indexing Word-Based Indexing Characters .61 Words using phrase operator .63 (+3.3%) Words .65 (+6.6%) Table 3: TIPSTER Japanese Retrieval Results References [1] W.B. Croft, H. Turtk[OCRerr] D. Le'vis, `[OCRerr]The Use of Phrases aud Structured Queries in Information Retrieval", Proceedings of SIGIR 91, 32-45, (1991). [2] W.B. Croft and H. Turtle, Text Retrieval and Inference", in Text-Based Intelligent Systems, Paul Jacobs (ed.), Lawrence ErH)aunl, New Jersey, 127-1.56, (1992). [3] H.R. Turtle and W.B. Croft, "Evaluation of an Inference Network-Based Retrieval Model", ACM Transactions on I?zforination Systems, 9(3), 187-222, (1991). [4] H. Turtle and W.B. Croft, [OCRerr]A Comp[OCRerr]ison of Retrieval Models", Computer Journal, 35(3), 279-290, (1992). [5] C. J. Van Rijsbergen, I'[OCRerr]forr'iation Rctrieval. Butterworths, (1979). 105