dependency parsing with an extended finite-state approach

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1、DependencyParsingwithanExtendedFinite-StateApproachKemalOflazer∗SabancıUniversityThisarticlepresentsadependencyparsingschemeusinganextendedfinite-stateapproach.Theparseraugmentsinputrepresentationwith“channels”sothatlinksrepresentingsyntacticdepen-dencyrelations

2、amongwordscanbeaccommodatedanditeratesontheinputanumberoftimestoarriveatafixedpoint.Intermediateconfigurationsviolatingvariousconstraintsofprojectivedependencyrepresentationssuchasnocrossinglinksandnoindependentitemsexceptsenten-tialheadarefilteredviafinite-statefil

3、ters.WehaveappliedtheparsertodependencyparsingofTurkish.1.IntroductionFinite-statemachineshavebeenusedformanytasksinlanguageprocessing,suchastokenization,morphologicalanalysis,andparsing.Recentadvancesinthedevelop-mentofsophisticatedtoolsforbuildingfinite-states

4、ystems(e.g.,XRCEFiniteStateTools[Karttunenetal.1996],AT&TTools[Mohri,Pereira,andRiley1998],andFi-niteStateAutomataUtilities[vanNoord1997])havefosteredthedevelopmentofquitecomplexfinite-statesystemsfornaturallanguageprocessing.Inthelastsev-eralyears,therehavebeen

5、anumberofstudiesondevelopingfinite-stateparsingsystems(Koskenniemi1990;Koskenniemi,Tapanainen,andVoutilainen1992;Grefen-stette1996;ChanodandTapanainen1996;Ait-MokhtarandChanod1997;Hobbsetal.1997).Anotherstreamofworkinusingfinite-statemethodsinparsingisbasedonappr

6、oximatingcontext-freegrammarswithfinite-stategrammars,whicharethenprocessedbyefficientmethodsforsuchgrammars(Black1989;PereiraandWright1997;Grimley-Evans1997;Johnson1998;Nederhof1998,2000).Therehavealsobeenanumberofapproachestonaturallanguageparsingusingextendedfi

7、nite-stateap-proachesinwhichafinite-stateengineisappliedmultipletimestotheinput,orvariousderivativesthereof,untilsometerminationconditionisreached(Abney1996;Roche1997).Thisarticlepresentsanapproachtodependencyparsingusingafinite-stateap-proach.Theapproachissimila

8、rtothoseofRocheandAbneyinthatallthreeuseanextendedfinite-stateschemetoparsetheinputsentences.Ourcontributionscanbesummarizedasfollows:•OurapproachdiffersfromRoche’sandAbney’s