SP500215 TREC-2 Document Retrieval Experiments using PIRCS chapter K. Kwok L. Grunfeld National Institute of Standards and Technology D. K. Harman the net are used to initialize the tree leaf nodes, from which activation spreads to the query root node. Processing at the nodes implements soft-Boolcan evaluation [SaFW83] in the OTO q a ffiv'a 0 Fig.1: 3.Layer PIR Network 3. System Design ifi D Our previous software for fl[OCRerr]EC1 has extraneous processing that produces several intermediate files for other DTQ direction resulting in a third RSV: S1. The RsVs are latter combined for ranking retrieval outputs. Affi d1 qj[OCRerr] ½ DTQ Fig.2: Soft-Boolean Ouery Network w D purposes. These consume a lot of disk space for 1arg[OCRerr] scale collections. We spent a substantial amount of time to revamp our system, resulting in a more streaflilined flow- chart as follows: DTQ Soft- Boolean d. Pre?rocss --> Create --> Initiate --> Network --> Retrieve --> Evaluate Documents Direct files I Network Learning and Rank PreProcss " ---I Queries II\ Relevance File -->-------- add[OCRerr] we also took the ([OCRerr]-iIiity to [OCRerr] our system reslilting in several inn[OCRerr][OCRerr]ative [OCRerr] described in the following sub[OCRerr][OCRerr]tions: 3.1 Full Inverted File Eliminated II is useful to view a textbase as a document by term matriL If one stores the matrix rowwise. we call it a direct file. in oo'trast to an inverted file which stoes the matrix cahinuwise. The inveeted file is usal to support fast retrieval while the direct file is uscful for feedback learning and query eapansion when gi[OCRerr]en oeram documents boiling relevant to certain queries. [OCRerr] addition, the raw textfile is 234 useful for display lrurpses after a retrieval ranj[OCRerr]ed list is prodi[OCRerr]cCL If one assumes that each of these these flees are [OCRerr]p-miteiy - in sire ofNbytes. we need ammtm[OCRerr]um of 3N -, which is quite siib:ianti[OCRerr][OCRerr] Removing the raw textmay not win user support during display unless the dircct file encodes all sic[OCRerr][OCRerr]ords. pimctuatio[OCRerr] and pamgra[OCRerr] [OCRerr]ctea of the original- Most Systems the direct file and re-[OCRerr]uce a [OCRerr]eet of it fr[OCRerr] raw text when needei This results in a re-went of [OCRerr] bytes. We choose. however, to - the directflle and produce our network: with respect to the queies dynamically as needed without first producing an inveteed file first. Our network actually contains both direct and `inverted' dat[OCRerr] It resides in memory to support leering and retriev[OCRerr] By this ~WIk T ifi T