Refereed full papers (journals, book chapters, international conferences)

1994

@inproceedings{RWJ1994,
	vgclass =	{refpap},
	author =	{S. E. Robertson and S. Walker and S. Jones and M. M.
	Hancock-Beaulieu and M. Gatford},
	title =	{Okapi at {TREC}--3},
	booktitle =	{{NIST} Special Publication 500-225: Overview of the Third
	{T}ext {RE}trieval {C}onference ({TREC}-3)},
	address =	{Gaithersburg, Maryland, USA},
	pages =	{109--126},
	month =	{November~2--4},
	year =	{1994},
	url =	{http://trec.nist.gov/pubs/trec3/papers/city.ps.gz},
	abstract =	{The sequence of TREC conferences has seen the City
	University Okapi IR system evolve in several ways. Before TREC--1 it
	was a very traditional probabilistic system comprising closely
	integrated search engine and interface, designed for casual use by
	searchers of bibliographic reference databases. During the course of
	TREC--1 the low�level search functions were split off into a separate
	Basic Search System (BSS) [2], but retrieval and ranking of documents
	was still done using the ``classical'' probabilistic model of Robertson
	and Sparck Jones[7] with no account taken of document length or term
	frequency within document or query. Four runs were submitted to NIST
	for evaluation: automatic ad hoc, automatic routing, manual ad hoc and
	manual ad hoc with feedback. The results were undistinguished, although
	not among the worst.  Of the ad hoc runs, the manual was better than
	the automatic (in which only the CONCEPTS fields of the topics were
	used), and feedback appeared beneficial. We have only recently noticed
	that our TREC--1 (and probably also TREC--2) results would have been
	considerably worse had it not been that the system at that time could
	not handle documents longer than 64K, and so the longest few hundred
	documents in the database were truncated. The TREC--1 automatic ad hoc
	run redone on the full database (with cutoff at 200 documents) gives an
	11--pt average of 0.10 (0.12), precision at 5 documents 0.37 (0.50);
	and at 30 documents 0.36 (0.42) (TREC--1 results in parentheses). This
	appears to be because the simple weighting scheme tends to favour long
	documents, particularly FR, few of which are relevant. For TREC--2 the
	simple inverse collection frequency (ICF) term�weighting scheme was
	elaborated to embody within�document frequency and document length
	components, as well as within�query frequency, and a large number of
	weighting functions were investigated.},
}