Manipulation of trees in information retrieval

/.} ,I n t r o d u c t i o n All inf~n'm:t{i~)l,., ret, ri( 'val system is (tesigned t() provide "tli:-tvo!'s It) l'('(llIOSld, I'()F i i l f ( ) l ' l l la i io t l . I l l s ( ) n l e S VS{OInS~ l'('ful'('!i('c:< i l l thc f4)l'll l O[ d<)cimlel i t or i l l )ok t i t les al'o ( i l ) /a [ ] i ( : r i l 'al}i('l" l ha l i sf)e('ific i lenis ()f infor i l iat io l l ; tiles() io['e!'cile(,s. {l/ iurn, l(,~.t t,> (he act !lal r('(lttired infori l tat ioi i . If a-'.ttolli~tlic nu'lho([> ave i() }~e used for tit(' per[ornlance of iP.f()l ' l t latj() l i l ( ' t r i ( ' va l o[)(,l't/iiOliS, pl 'ot 'ed/l l 'es I l i t tst be !>r<)vide<l for fi)nr !)r lucipat '<ypes of lasks: the analysis of iilf(Jrln~itioii i'c.qiicsls ali(t of stored <l-ira; the gelieration of inf( i in ial i!)ii i(14'ili itlca~ i .ns which display Will(ted reiu)ions and associali<)ns i)(q:weeli ilenls of in format ion; ihe sinip}if icatiou, c(m(lensation, or tralisforritlation (if illf<)l'Hla!i()ll ideulifi<'uii(ms to (;onfol'ltl with sonic given ciassificalioii sysletn: aiid the ntatching of the modif ied request idei i l i f icai ions w i i h ihe data identif ications. .~[tlCtJ of the worl,, ill a l l tontal ic ii ifol'nlai;ion retr ieval i.-eoi l( 'entratcd iu i tw lasl area, and cons(sis, in parl imllai ', of pioced'u'i ' . < I()1' tim arraiigenlenl: of (reins of in let 'mat(on ill StOl'i/~o, ((lid for the exlra( ' l ion of tilose items which ('()l'respoll(l exactly to some givell input, ('riiori()lt. ~li('h pro~ralris (it) li(il cov('r lnaliV of the req~liven-l(,iiis for a tvon la l ic in format ion retr ieval, firsl; })(,catlse al l CXi.(('I l l l t i i ('h })e{w('( ' l l i n f ( i r n l a l i on re(lttests and ~lored data wi l l freq(lo|~tly i}()t reoov(,r t | ic desired it.eros, and second be<.ause ih(, in i t )or ial i t problenis COllliOcted wi th the autonlat ic almlvsis ()f infor lnat iou are ig, iored, fit fact, most ()f ~tle investigat()rs Cil'elinlvelit the <litl icultics inhereig iti autonmt ie aiialysis by assuming so(lie sort of i l lal i l ia! ly prl 'pm'('d (lip(it, or (?is(" use relat ively rlldinlentary st(iris(toni te<'hniques, such as word fre(luency cotlnts..As tt res|ilt the practical results aellieved in this area are fully applicable only to simplified or artificial, semiformal languages, or are restricted to snmll, specific areas of discourse iri the natura l language. In either case, tit(, practical situation which requires the pr<)eessing of i)fformation expressed in the natural l anguage in a relatively unrestricted area of discourse is not included. Moreover, results <)btained for the siInplified st(nations cannot in general be extended to cover the desired problem area.