How To Write A Machine Translation

Transcription

1 Oconteudodopresenterelatorioedeunicaresponsabilidadedo(s)autor(es). (Thecontentsofthisreportarethesoleresponsibilityoftheauthor(s).) TextStructureAimingatMachineTranslation HoracioSaggionandAriadneCarvalho RelatorioTecnicoDCC{95-22 Dezembrode1995

2 TextStructureAimingatMachineTranslation DepartamentodeCi^enciadaComputac~ao HoracioSaggionandAriadneCarvalho UniversidadeEstadualdeCampinas Campinas-SP-Brazil CaixaPostal6065 phenomenaconsideredhereisdeniteanaphora. tuguese.theemphasisoftheworkisonthedeterminationofthetextstructureofsuch abstracts,makinguseofthenotionsofcohesionandcoherence.themaincohesion machinetranslationsystem.wehaveusedassourcetextscienticabstractsinpor- beabletocapturethesemanticcontentoftheoriginaltext.theworkpresentedhere isconcernedwiththeautomaticgenerationofsucharepresentation,tobeusedbya Machinetranslationreliesontheexistenceofameaningrepresentationwhichmust Abstract 1Introduction AMachineTranslation(MT)systemcanbeseenasaspecialkindofNaturalLanguage Understanding(NLU)system.ThetextintheSourceLanguage(SL)isanalysedbya programwhichproducesameaningrepresentationofthetext,tobeusedbyageneration Keywords:MachineTranslation,TextualStructure,CoherenceRelations,DeniteAnaphora. programwhichwillproducetheconveyedmessageinthetargetlanguage(tl),seefigure freerepresentation,whichincludessemanticandsyntacticfeaturesnecessaryforrepresentingtheexactmeaningofwordsandsentences[lewis,1992]. ThisworkisbeingsponsoredbyFAPESP(Fundac~aodeAmparoaPesquisadoEstadodeS~aoPaulo) ThiskindofapproachtoMTreliesontheexistenceofaninterlingua,akindoflanguage Figure1:NLUSystem andcnpq(conselhonacionaldedesenvolvimentocientcoetecnologico) 1 1. SOURCE LANGUAGE UNDERSTANDING MEANING GENERATION TARGET LANGUAGE

3 MTsystem.Inourapproach,textistreatedasacoherentandcohesivewhole.Weaim tions[tucker,1984,scolum,1985]and,asaresult,textisrepresentedasadisconnected atanexplicitrepresentationofsomediscoursephenomenaasameansofobtaininghigh delitytotheoriginaltext[danlos,1987].weareconcernedherewiththedevelopmentof qualitytranslation.themainideaisthattherepresentationmustincludenotonlythe ameaningrepresentationofabstractsfortechnicalpapersinportuguese,tobeusedbyan sequenceofsentences.thechoiceontherepresentationwillinuenceaspectssuchas- MeaningrepresentationsinMTsystemsareusuallyextensionsofsyntacticrepresenta- formimprovestherightchoiceofconnectivesandsupercialformsduringthegeneration propositionalcontentofthetext,butalsothecoherencerelationsthattiepropositionstogetherinthetext.webelievethattherepresentationofcoherencerelationsinanabstract process[mooreandparis,1994].thechoiceofaconnectivealsoimposesrestrictionson therealizationofthepropositionsinvolvedintherelation. 2AbstractsandtheirStructure representationisshown;insection5wepresentadetailedexampleand,nally,insection 6wepresentourconclusions. anabstractispresented;insection3weintroducethemeaningrepresentationwhichwill begeneratedbythesystem;insection4theprocessofautomaticconstructionofthe Therestofthepaperisorganizedasfollows:inSection2thegeneralstructureof wayinspiteofthefactthatabstractsarewrittentobeasbriefandconciseaspossible,they presentcharacteristicsobservedinlargertexts,inparticularcoherenceandcohesiverelations[hobbs,1978a,hobbs,1978b,mannandthompson,1983,mannandthompson,1987, abstracttogivethemenoughinformationabouttheworkinordertodecideiftheywill Itprovidesthereaderwithabriefpreviewofthepaper.Manyreadersdependonthe Anabstractistherstsectionofareport,comingafterthetitleandbeforetheintroduction. readtheentirereportornot.abstractsfromalmostalleldsarewritteninaverysimilar HallidayandHasan,1976]. mayincludethefollowinginformation: andaccordingto[weissbergandbuker,1990,hutchins,1985,jordan,1991],anabstract anabstractwillbeamixtureofboth. andindicative,whichsimplystatethefactthatcertaintopicsarecovered.butingeneral tional.accordingtothebraziliantechnicalnormsassociation(abnt)[abnt,1987], informative,whichincludeactualresults,guresandconclusionsfromsourcedocuments, Accordingto[Hutchins,1985,Jordan,1991],twobasictypesofabstractsareidentied: background:where,asthenamesays,backgroundinformationmustbegiven; purposeorobjective:wheretheobjectivesoftheworkmustbedescribed; Thetypeandtheorderoftheinformationincludedinanabstractareveryconven- method:wherenewtechniquesandmethodologicalprinciplesaredescribed; 2

4 aboutthemethodwhichwasusedandtheresultswhichwereobtained,verbsshouldbe talkingaboutthepurposeofthework,verbsshouldbeinthepresenttense;whentalking languageconventions.themostcommonistheconventiononverbuses,whichis:when conclusion. results:wherenewfactsarepresented; auxiliariesmightbeused. Engenharia"1.Wehavechosentostudyabstractsfromthismagazinebecausesubmissions inthepasttense;intheconclusionverbscouldeitherbeinthepresenttenseormodal Ourresearchisbasedonacorpusofabstractstakenfromthe\RevistadeEnsinode Aswellasnormsonwhichinformationshouldbepresentedinanabstract,therearealso toitmustagreewiththenormsfromtheabnt. takenfromthismagazine: activeorpassivevoiceisusuallyusedwhentheauthoristalkingaboutthepaper.asthe \cues"areusefulfortheidenticationofthetypeofinformationpresentintheabstract. workisgenerallyprevioustothepaper,pasttenseisusedtointroducedetailsaboutthescienticwork(experiments,experiences,methodologicalandtheoreticalframework).these Someempiricalfactscanbeveriedinthecorpus.Forexample,presenttenseinthe Figure2showsanexampleofanabstract[daSilveiraNetoandHernandezMendoza,1988] (4)testee(5)analisetermicadestetipodetrocador.(6)Usandoometodore- (1)Trocadoresdecalorcompactoss~aoelementosbasicosedealtaeci^encia.(2) Estetrabalhoapresentaummetodosimples(3)usadoparaodesenvolvimento, method(7)undergraduatelevelstudentscanestimatepressuredropsandheat comendado,(7)alunosdegraduac~aopodemestimaraquedadapress~aoecoe- cientesdetrocadecalor(8)normalmenteutilizadosemengenhariatermica. workshowsasimplemethod,(3)usedforthedevelopment,(4)testingand(5) thermalanalysisofthistypeofheatexchanger.(6)usingtherecommended (1)Compactheatexchangersarebasicandhigheciencyelements.(2)This exchangecoecients(8)commonlyusedinthermalengineering. easyreferenceintherestofthepaper. 3RepresentingtheStructureoftheText Thenumbersattachedtothetextarenotpresentintheoriginal;theyareprovidedfor Figure2:Arstsampleabstract Inourapproachtextisrepresentedasastructurewhichcapturestheinformationalcontent,thecoherencerelationsbetweenpartsofthetextandthepropositionalcontent.The 1InEnglish:EngeneeringTeachingMagazine3

5 etc)andcopeswithagroupofsentenceswhichconstitutesoneofthemainsegmentsof ofthetextwillconveydierentkindsofinformation[grimes,1975].therootofthetree thetext,whichcanbeeithersinglepropositionsorgroupsofpropositionstiedtogetherby representsadierentinformationalstatus(backgroundinformation,method,conclusions, thetext.internalnodesofthetreerepresentcoherencerelationsbetweensubsegmentsof coherencerelations.finally,theleavesrepresentthepropositionalcontent. informationactuallypresentintheabstract.thisisbasedonthefactthatdierentparts representationcanbeseenasaforest.eachtreeintheforestrepresentsadierentkindof denedaccordingtothetypeofinformationpresentinthetext(asdescribedinsection 2)andalsoaccordingtotheanalysisofthecorpusofabstractstakenfromthemagazine. asetofinformationalcategories(ic)torepresenteachtextspan.thesecategorieswere groupedtogetheraccordingtosyntacticandsemanticinformation.weareworkingwith throughapartitionofthetextintotextspans,whicharelinearsequencesofsentences Theinformationalcontentrepresentsthemainsegmentsoftheabstract.Itisobtained 3.1InformationalContent semanticinformation,suchastense,aspect,andsemanticfeaturesattachedtothelexical items.thesecategoriesare: Theidenticationofeachcategorywhichappearsinanabstractreliesonsyntacticand Figure2,weobtainthefollowingsubset: ICfBackground,Objective,Method,Experiment,Recommendation,Suggestions, Backgroundisgiveninproposition(1),Objectiveisgiveninpropositionsfrom(2)to TheoveralltextisrepresentedthroughasubsetofIC.Fromtheexampleshownin AbstractfBackground,Objective,Recommendationg Conclusion,Resultsg ingforlocalcoherence.severalresearchershavealreadyinvestigatedtherelationsthat assistageneratorinthechoicestobemadewhenthetimefortranslationcomes. 3.2CoherenceRelations Theanalysisofthecorpusrevealedtheexistenceofvariouscoherencerelations,account- howthispartitionwasmade.theidenticationofthesecategoriesinthesourcetextwill (5),andRecommendationinpropositionsfrom(6)to(8).InSection5wedescribeindetail holdinapieceofcoherenttext:coherencerelations[hobbs,1978a],rhetoricalrelations [MannandThompson,1983],SemanticRelations[Hutchins,1987].Inourworkwegave system. formaldenitionstotheserelationsaimingattheircomputationalusebyanautomatic CRfElaboration,Parallel,Sequence,TemporalSequence,CauseConsequence, Weareworkingwiththefollowingsetofrelations: Contrastg 4

6 holdsbetweentwopropositions(a)and(b)if(a)introducesanentitythatisfurtherelaboratedinproposition(b).oneoftherulesfortheelaborationrelationfollows: Relationsmayrelatepropositionsorgroupsofpropositions.TheElaborationrelation areotherrulesforelaborationwhichwillnotbepresentedhere. proposition(b)containsaverbalpredicateqwhich\talksabout"thesameentityy.there and(b)ifproposition(a)containsaverbalpredicatepwhichintroducesanentityy,and InFigure2proposition(2)introducestheentity\metodo"thatisfurtherelaboratedin ThisrulestatesthatthereexistsanElaborationrelationbetweentwopropositions(a) q(event2;y;z)2(b)gj=(a)elaboration(b) fp(event1;x;y)2(a) propositionsfrom(3)to(5).theelaborationliesontheutilizationofthe\metodo".the samerelationholdsbetweenpropositions(7)and(8);(7)introducestheentities\quedada press~ao"and\coecientesdetrocadecalor";thetwoarefurtherelaboratedinproposition (8).Inthiscasewehavethefollowingstructure: proposition(8):use(useevent;y;z) proposition(7):estimate(estimateevent;x;y) wherethecontrastpredicatemustbedened.thisrelationisnotpresentintheabstract samemainpredicator,buttheargumentsareincontrast.moreformally TheContrastrelationlinkstwopropositions(a)and(b)ifbothpropositionssharethe fromfigure2.considernowthetextsegmentpresentedinfigure3[bazzoandpereira,1989]: contrast(y;z)gj=(a)contrast(b) p(event2;x;z)2(b) fp(event1;x;y)2(a) howeverempiricismandcreativitywillneverbedisregarded. ausa. (1)Engineeringdependsmoreandmoreonscienceandspecictechniques,(2) (1)Aengenhariadependecadavezmaisdasci^enciasedetecnicasnelas baseadas,(2)masjamaisvaiprescindirdoempirismoedacriatividadedequem veriedbetweenpropositions(1)and(2):inproposition(1)\engenharia"ispresentedas dependentonscience,andinproposition(2)itispresentedasdependenton\criatividade", twoopposedconcepts. Theexplicitmark\mas"isanindicationofcontrast.Thecontrastcanactuallybe Otherrelationsaresimilarlyspecied,andseveralrulesaredenedforeachofthem. Figure3:Textsegmentfromthecorpus 5

7 3.3PropositionalContent Eachsentenceinthesourcetextoriginatesoneormorepropositionsasaresultofsyntacticandsemanticanalysis.Thepropositionalcontentisasetofpropositionsthatcarry Asetofvariables themessageoftheabstract.therepresentationisbasedonrstorderrepresentations. Propositionsarerepresentedthrough: fromverbphrases.predicateshavemandatoryargumentsandalistisusedtorepresent Asetofpredicates Entitiesarederivedfromnounphrasesinthesentence.Eventsandstatesarederived standingforrelationsofxedarity,whichrelatetheentitiesintheproposition.predicatesareassociatedwithitemsfromtheportugueselanguage. representingtheentityreferentsandeventreferentsintheproposition. tureofthesyntactictreeandonthesemanticinformationattachedtolexicalitems. pairsofnonco-referringexpressions(intrasententialanaphora)usingsyntacticrestrictions (parsetree)producedbytheanalysis[winograd,1983].thetreeisalsousedtoidentify [Raposo,1992].Semanticanalysisproducespredicatesandargumentsbasedonthestruc- grammaticalrulesanditisbrokendownintopropositionsaccordingtothesyntactictree themultiplecasesofcomplementation.eachsentenceinthetextisanalysedaccordingto setofknownentities,whichrestrictthepossibleantecedentsforadenitenounphrasein [Hirst,1981a,Hirst,1981b]mustberesolved.Theresolutionisbasedonsyntacticrestrictions(genre,number)aswellasonworldknowledge[NirenburgandCarbonell,1987].A thefollowingtext,ismaintained.thesetincludestheentitiesearlierintroduced(explicitly) aswellastheentitiesassociatedwiththem.pronounresolutionisessentialineverymt system[wilks,1973]andthecorrectchoiceofanantecedentforadenitefullnounphrase isessentialinthevericationofthecoherencerelations. Inordertocorrectlyrepresenttheentitiesinthepropositionalcontent,deniteanaphora semanticinterpretationofthenounphraseresultedinaincompleteentityrepresentedby theexpression(a): Theresolutionofthedenitenounphrase\estadisciplina"isrequired,becausethe Asanotherexample,considertheabstractpresentedinFigure4[deAraujoandSzeremeta,1985]: thereisnopreviousexplicitoccurrenceofthispredicateinthetext.nevertheless,inthe ofknownentities.thesearchisbasedonthepredicate\disciplina".asitcanbeseen, rstsentenceoftheabstract,thenounphrase\calculonumerico"wasintroducedand belongstothelistofknownentities: thesemanticinterpretationofthisexpressionproducedthefollowingterm,whichindeed Theresolutionoftheexpressionisbasedonthesearchforanantecedentinthelist (a)disciplina(x1) (b)disciplina(x2,name:calculonumerico) 6

8 dosfuturosengenheiros.algumasalterac~oesnametodologiadeensinodesta Withtheincreasingutilizationofprogrammablecalculatorsandmicrocomputers,itbecomesnecessarytoupdatetheteachingapproachofNumericalAnalysiingthesesubjectsaresuggestedandsomerecommendationsaremadeforthe utilizationofprogrammablecalculators. instructionforfutureengineers.somechangesonthemethodologyforteach- calculadorasprogramaveis. disciplinas~aosugeridasefeitasalgumasrecomendac~oesquantoautilizac~aode necessariaaadequac~aodoplanodeensinodecalculonumericoparaaformac~ao Comautilizac~aodecalculadorasprogramaveisemicrocomputadores,torna-se cionaraosalunosfundamentosbasicossobreateoriademodelos.ociclode aulaspraticastemcomoobjetivos(...) hariaministradanocursodeengenhariamec^anicadaufuaqualvisapropor- OpresentetrabalhotemcomometadivulgaradisciplinaSimilitudeemEngen- Figure4:Asecondsampleabstract providingthestudentswithbasicfoundationsofmodelingtheory.practical activitieswereplanned(...) TheobjectiveofthispaperistodivulgethecourseSimilitudeinEngineering, taughtatthemechanicalengineeringdepartmentofufuwiththeobjectiveof praticas"isintroducedandthisphrasemustberesolved;thesemanticinterpretationof So,theresolutionofexpression(a)becamespossiblethroughexpression(b). Asanadditionalexample,considertheabstractpresentedinFigure5[GomideandFernandez,1985]: Inthesecondsentenceoftheabstract,thedenitenounphrase\Ociclodeaulas Figure5:Athirdsampleabstract entity\aulas".inordertoresolvethedeniteexpression\ociclodeaulaspraticas",itis necessarytoresolveexpression(d).intherstsentenceoftheabstractthenounphrase\a thisexpressionproducedthefollowingterms: disciplinasimilitudeemengenharia"isintroducedandthesemanticinterpretationofthis nounphraseresultedinacompleteexpressionrepresentedbythefollowingterm: Notethatterm(d)isincompletebecausethesystemdoesnotknowtheidentityofthe (d)aula(x4,qualier:praticas) (c)ciclo(x3,specier:x4) (e)disciplina(x5,name:similitudeemengenharia) 7

9 \aulas"thesystemintroducedthefollowingtermassociatedwithexpression(e): (d)becamesnallypossible. Withthesetermsincorporatedtothelistofknownentities,theresolutionofexpression Inadditiontothisexpression,andtakingintoaccountthefactthata\disciplina"has 4ConstructingtheMeaningRepresentation ThediagraminFigure6showsthemainprocessesandsourcesinvolvedintheconstruction (f)aula(a(x5)) text.theabstractstructureassemblerlinksacoherentspantotheglobalorganizationof Assemblerisresponsibleforselectingthecoherencerelationsthatlinkpropositionsinthe ofthetextstructure.thestructureisconstructedbytwomainprocesses.thecoherence thetext. COHERENCE PROPOSITIONS SEMANTIC SYNTACTIC SIGNALS COHERENCE PARTIAL STRUCTURE RULES ASSEMBLER COHERENT SemanticandSyntacticSignals:guidethecoherenceassemblerintheselectionof Propositions:areproducedasaresultofsyntacticandsemanticanalysis. Theseprocessesoperateonthefollowingcomponentsofthemeaningrepresentation: Figure6:MeaningRepresentationConstruction SPAN signalsincludediscoursemarkersthatdirectlysignalthestructureofthediscourse ABSTRACT [HirschbergandLitman,1993].Thesemarkersaretheprimaryindicationofthepresenceofacoherencerelationinthetext.Tense,aspectandsemanticinformation thecoherencerelationsandalsoindecidingwhereacoherentspanends.syntactic STRUCTURE ASSEMBLER attachedtolexicalitemsprovideameanstodecideaboutthelimitsofatextspan TEXT [GroszandSidner,1986]. STRUCTURE 8

10 BACKGROUND OBJETIVES PartialStructure:isusedtostorepropositionsandsegmentsalreadylinkedandwaitingforadditionalprocess.WhenprocessingapropositionPk,twoproblemsmustbe resolved: CoherenceRules:deneconditionsthatpropositionsmustsatisfyinordertobelinked togetherbyacoherencerelation. Propositionsmustbetemporarilysaveduntiladecisionismade. (b)decideonhowtheattachmenttoasegmentwillbedone. (a)decidetowhichtextsegmentthepropositionpkwillbeattached; Figure7showsthestructureproducedasaresultoftheanalysisoftheexamplefromFigure 5DetailedExample CoherentSpan:isagroupofpropositionsrelatedbycoherencerelations.ItcarriesinformationalcontentassociatedwithoneoftheInformationalCategoriesearlier 2.Themainprocessesthatledtothisstructureare: presented. (1) ELABORATION Breakingeachsentenceintopropositions:usingsyntacticandsemanticanalysis. (2) PARALLEL Determiningreferencesfordeniteanaphora:thenounphrase\estetrabalho"in RECOMENDATIONS (3) (4) (5) proposition(2)isresolvedusingspecicknowledgeaboutabstracts.thecorrespondingdenitenounphraseis\thispaper". Figure7:TextStructure ENABLE 9 (6) ELABORATION (7) (8)

11 Variousentitiesonlymakesenseinthecontextofabstracts.Theseentitiesinclude \theauthors",\thepaper",\thework",\theobjective"andthelike.thisinformation Determiningthelimitsofeachtextspan:inproposition(1)theuseoftheverbalform thepreviousdiscourse. inproposition(1).thenounphrase\ometodorecomendado"isalsoresolvedusing precedingdiscourse.theantecedentis\trocadoresdecalorcompactos"introduced antecedentforadenitenounphrase. Thenounphrase\estetipodetrocador"inproposition(5)isresolvedusingthe isincludedintheknowledgebasesystemandisveryusefulwhenlookingforan Objectivecategoryisselectedanditspansuptoproposition(5).Inproposition(6) wecandeducethatthepropositionreallymarkstheobjectiveofthepaper.sothe subjectinthesentence.takingintoaccountthefactthata\paper"hasanobjective, nounphrase\estetrabalho",whichwasfoundtomean\thispaper",isactingas carries,ingeneral,purposeorobjectiveinformation[jordan,1991].additionally,the classiedasbackground.inproposition(2)theverb\apresentar"isused.thisverb \Is-a"sentencesareusuallyanalysedinthisform[Sidner,1978].Soproposition(1)is \s~ao"carriessemanticalinformationaboutgeneralfacts(oneentityis\dened"). DeterminingCoherenceRelations:syntacticmarksguidetheselectionofcoherence orasequencerelation.butnotethatthesameargument,\estetipodetrocador",is relations.forexamplepropositionsfrom(3)to(5)arelinkedbycoordination,syntacticallyindicatedbycommasandbytheconjunction\e";thiscouldmarkaparallel theitem\recomendado"marksthebeginningofanewtextspanwhichisclassied asrecommendation.figure7showsthelimitsofeachtextspan. usedinthethreepropositions,whichsignalsapreferenceforaparallelrelation.the structureandthesourceinputwastreatedasadisconnectedsequenceofsentences.asa 6Conclusions Traditionalapproachestomachinetranslationhaveusuallyneglectedtheproblemoftext othercoherencerelationsfromtheabstractshowninfigure2areshowninfigure result,therepresentationusedbytheseapproacheswerenotabletocaptureandtomake 7. ofabstractsfromscienticpapersinportuguese.thisrepresentationmustcapturethe informationalcontent,thecoherencerelationsandthepropositionalcontentoftheinput useofthecoherencephenomenapresentintheinput. text.webelievethatthisrepresentationisappropriateformachinetranslationbecauseit choosethesupercialformsinordertocorrectlyexpressthemessageinthetargetlanguage, preservingtheoriginalstructureofthetext.severalstepsareinvolvedintheconstruction thetext.representingthelinguisticstructureofthetextenablesageneratorprogramto copesnotonlywiththemessagewhichisbeingconveyed,butalsowiththestructureof Weareconcentratedonthespecicationandconstructionofameaningrepresentation ofsucharepresentation:syntacticanalysis,semanticinterpretation,anaphoraresolution, 10

12 knowledgeaboutthedomainofthediscourseintothesystem;moreresearchisalsoneeded determinationoftextspansanddeterminationofcoherencerelations.weareworkingwith asetoftheserelations,whichweredenedaccordingtothephenomenaobservedinthe Also,wehaveonlytreatedtheproblemofdeniteanaphorathroughtheincorporationof corpus.additionalresearchisneededinordertoexpandthissettocopewithmorerelations. WewouldliketothankJorgeStolforhisvaluablecommentsonapreviousversionofthis paper. tocopewithotherkindsofanaphora. References Acknowledgements [BazzoandPereira,1989]Bazzo,W.A.andTeixeiradoValePereira,L.Criatividadena [Danlos,1987]Danlos,L.TheLinguisticBasisofTextGeneration.StudiesinNaturalLanguageProcessing,CambridgeUniversityPress,1987. [ABNT,1987]ABNT-Associac~aoBrasileiradeNormasTecnicas.Resumos Engenharia.RevistadeEnsinodeEngenharia,S~aoPaulo,8(1):8-11,10semestre [dearaujoandszeremeta,1985]dearaujo,n.d.andszeremeta,j.f.umaexperi^encia [dasilveiranetoandhernandezmendoza,1988]dasilveiraneto,a.andhernandezmendoza,o.s.trocadoresdecalorcompactos-bancadadetestes.revistadeensino noensinodecalculonumericonaufsc.revistadeensinodeengenharia, deengenharia,s~aopaulo,7(1):43-48,10semestre1988. [GomideandFernandez,1985]Gomide,H.A.andFernandez,E.F.CursodeSimilitudeem [Grimes,1975]Grimes,J.TheThreadofDiscourse.MoutonandCompany,TheHague, 4(2): ,S~aoPaulo,20Sem Engenharia.RevistadeEnsinodeEngenharia,4(2): ,S~aoPaulo,20Sem [HallidayandHasan,1976]Halliday,M.A.andHasan,R.CohesioninEnglish.London, [GroszandSidner,1986]Grosz,B.J.andSidner,C.L.Attention,IntentionsandtheStructureofDiscourse.ComputationalLinguistics,Vol.12,Num.3,July-September NotesinComputerScience119.Springer-Verlag, Netherlands,1975. [Hirst,1981a]Hirst,G.AnaphorainNaturalLanguageUnderstanding:ASurvey.Lecture LongmanPress,1976.

13 [Hobbs,1978a]Hobbs,J.R.CoherenceandCoreference.SRIInternational.TechnicalNote [Hirst,1981b]Hirst,G.Discurse-OrientedAnaphoraResolutioninNaturalLanguageUnderstanding:AReview.AmericanJournalofComputationalLinguistics,Vol.7, [HirschbergandLitman,1993]Hirschberg,J.andLitmanD.EmpiricalStudiesontheDisambiguationofCuePhrases.ComputationalLinguistics,Vol.19,Num.3, ,August1978. Num.2,April-June1981. [Hutchins,1987]Hutchins,W.J.Summarization:SomeProblemsandMethods.Meaning: [Hobbs,1978b]Hobbs,J.R.WhyIsDiscourseCoherent?.SRIInternational.TechnicalNote [Hutchins,1985]Hutchins,W.J.InformationRetrievalandTextAnalysis.InNewApproachestotheAnalysisofMass,Media,DiscourseandCommunication.T.A. 176,November1978. TheFrontierofInformatics.K.Jones(Ed.),Cambridge,London,1987. vandijk(ed.),gruyter,berlin,1985. [Jordan,1991]Jordan,M.P.TheLinguisticGenreofAbstracts.InA.DellaVolpe(ed.),The [Lewis,1992]Lewis,D.ComputersandTranslation.InComputersandWrittenTexts. SeventeenthLACUSForum.LinguisticsAssociationofCanadaandtheUnited States,1991. [MannandThompson,1987]Mann,W.C.andThompsonS.A.RhetoricalStructureTheory:ATheoryofTextOrganization.ISIReprintSeries,ISI/RS ,June1987. Discourse.InformationSciencesInstitute,TechnicalReportRR ,November ChristopherS.Butler.Blackwell,1992. [MannandThompson,1983]Mann,W.C.andThompsonS.A.RelationalPropositionsin [MooreandParis,1994]Moore,J.D.andParis,C.L.PlanningTextforAdvisoryDia- [NirenburgandCarbonell,1987]Nirenburg,S.andCarbonell,J.IntegratingDiscourse logues:capturingintentionalandrhetoricalinformation.computationallin- guistics,vol.19,num.4,1994. [Scolum,1985]Scolum,J.ASurveyofMachineTranslation.ComputationalLinguistics, [Raposo,1992]Raposo,E.P.TeoriadaGramatica.AFaculdadedaLinguagem.Ed.Caminho,Lisboa,1992. Vol.11,Num.1,1985. PragmaticsandPropositionalKnowledgeforMultilingualNaturalLanguageProcessing.ComputersandTranslation(2).ParadigmPress,Inc.,

14 [WeissbergandBuker,1990]Weissberg,R.andS.Buker.WritingUPResearch.Prentice- [Tucker,1984]Tucker,A.B.APerspectiveonMachineTranslation:TheoryandPractice. [Sidner,1978]Sidner,L.S.TheUseofFocusasaToolforDisambiguationofDeniteNoun [Wilks,1973]Wilks,Y.AnArticialIntelligenceApproachtoMachineTranslation.In Hall,Inc.,1990. CommunicationsoftheACM.Vol.27.Num4.April1984. Phrases.TINLAP-2,1978. [Winograd,1983]Winograd,T.LanguageasaCognitiveProcess.Addison-WesleyPublishingCompany,INC.,1983. ComputerModelsofThoughtandLanguage,Schank,R.andColby,K.(Eds.), Freeman,SanFrancisco,

15 92-01ApplicationsofFiniteAutomataRepresentingLargeVocabularies, 92-03OntheIrrelevanceofEdgeOrientationsontheAcyclicDirectedTwoDisjointPathsProblem,C.L.Lucchesi,M.C.M.T.Giglio 92-02PointSetPatternMatchingind-Dimensions,P.J.deRezende,D.T.Lee C.L.Lucchesi,T.Kowaltowski RelatoriosTecnicos{ An(l;u)-TransversalTheoremforBipartiteGraphs,C.L.Lucchesi, 92-06ImplementingIntegrityControlinActiveDatabases,C.B.Medeiros, 92-04ANoteonPrimitivesfortheManipulationofGeneralSubdivisionsand thecomputationofvoronoidiagrams,w.jacometti D.H.Younger 92-08MaintainingIntegrityConstraintsacrossVersionsinaDatabase, 92-07NewExperimentalResultsForBipartiteMatching,J.C.Setubal 92-09OnClique-CompleteGraphs,C.L.Lucchesi,C.P.Mello,J.L.Szwarcter M.J.Andrade 92-10ExamplesofInformalbutRigorousCorrectnessProofsforTreeTraversing C.B.Medeiros,G.Jomier,W.Cellary 92-12BrowsingandQueryinginObject-OrientedDatabases,J.L.deOliveira, 92-11DebuggingAidsforStatechart-BasedSystems,V.G.S.Elias,H.Liesenberg R.deO.Anido Algorithms,T.Kowaltowski 14

16 93-02TheHierarchicalRingProtocol:AnEcientSchemeforReadingReplicatedData,NabordasC.Mendonca,RicardodeO.Anido HansK.E.LiesenbergRelatoriosTecnicos{ MatchingAlgorithmsforBipartiteGraphs,HerbertA.BaierSaip,ClaudioL AlexBFSAlgorithmforProperIntervalGraphRecognition,CelinaM.H SistemaGerenciadordeProcessamentoCooperativo,Ivonne.M.Carrazana, Lucchesi defigueiredo,jo~aomeidanis,celiap.demello 93-01TransformingStatechartsintoReactiveSystems,AntonioG.FigueiredoFilho, 93-08IntrospectionandProjectioninReasoningaboutOtherAgents,Jacques 93-06Implementac~aodeumBancodeDadosRelacionalDotadodeumaInterface 93-07EstadogramasnoDesenvolvimentodeInterfaces,FabioN.deLucena,Hans Nelson.C.Machado,Celio.C.Guimar~aes 93-09Codicac~aodeSequ^enciasdeImagenscomQuantizac~aoVetorial,Carlos Wainer K.E.Liesenberg Cooperativa,NascifA.AbousalhNeto,AriadneM.B.R.Carvalho 93-11AnImplementationStructureforRM-OSI/ISOTransactionProcessing 93-10Minimizac~aodoConsumodeEnergiaemumSistemaparaAquisic~aode CastroMachado AntonioReinaldoCosta,PauloLciodeGeus 93-12Boole'sconditionsofpossibleexperienceandreasoningunderuncertainty, ApplicationContexts,FlavioMoraisdeAssisSilva,EdmundoRobertoMauro DadosControladoporMicrocomputador,PauloCesarCentoducatte,Nelson 93-13ModellingGeographicInformationSystemsusinganObjectOriented PierreHansen,BrigitteJaumard,MarcusPoggideArag~ao Madeira 93-15UsingExtendedHierarchicalQuorumConsensustoControlReplicated 93-14ManagingTimeinObject-OrientedDatabases,LincolnM.Oliveira,Claudia donca,ricardodeoliveiraanido15 Data:fromTraditionalVotingtoLogicalStructures,NabordasChagasMen- Framework,FatimaPires,ClaudiaBauzerMedeiros,ArdemirisBarrosSilva

17 93-16LL{AnObjectOrientedLibraryLanguageReferenceManual,Tomasz 93-19Modelamento,Simulac~aoeSntesecomVHDL,CarlosGeraldoKrugereMario 93-18RuleApplicationinGIS{aCaseStudy,ClaudiaBauzerMedeiros,Geovane 93-17MetodologiasparaConvers~aodeEsquemasemSistemasdeBancosde DadosHeterog^eneos,RonaldoLopesdeOliveira,GeovaneCayresMagalh~aes Kowaltowski,EvandroBacarin 93-20ReectionsonUsingStatechartstoCaptureHuman-ComputerInterface 93-21ApplicationsofFiniteAutomatainDebuggingNaturalLanguageVocabularies,TomaszKowaltowski,ClaudioLeonardoLucchesieJorgeStol LucioC^ortes 93-23RethinkingthednaFragmentAssemblyProblem,Jo~aoMeidanis 93-22MinimizationofBinaryAutomata,TomaszKowaltowski,ClaudioLeonardoLucchesieJorgeStol Behaviour,FabioNogueiradeLucenaeHansLiesenberg 93-24EGOLib UmaBibliotecaOrientadaaObjetosGracos,EduardoAguiar 93-25Compreens~aodeAlgoritmosatravesdeAmbientesDedicadosaAnimac~ao, 93-27AUniedCharacterizationofChordal,Interval,IndierenceandOther 93-26GeoLab:AnEnvironmentforDevelopmentofAlgorithmsinComputational Patrocnio,PedroJussieudeRezende 93-28ProgrammingDialogueControlofUserInterfacesUsingStatecharts,Fabio ClassesofGraphs,Jo~aoMeidanis RackelValadaresAmorim,PedroJussieudeRezende 93-29EGOLib{ManualdeRefer^encia,EduardoAguiarPatrocnioePedroJussieude NogueiradeLucenaeHansLiesenberg Geometry,PedroJussieudeRezende,WelsonR.Jacometti Rezende 16

18 94-02Incorporac~aodoTempoemumsgbdOrientadoaObjetos,^AngeloRoncalli 94-01AStatechartEnginetoSupportImplementationsofComplexBehaviour, FabioNogueiradeLucena,HansK.E.Liesenberg AlencarBrayner,ClaudiaBauzerMedeiros RelatoriosTecnicos{ OnEdge-ColouringIndierenceGraphs,CelinaM.H.deFigueiredo,Jo~aoMeidanis,CeliaPicinindeMello 94-03OAlgoritmoKMPatravesdeAut^omatos,MarcusVinciusA.Andradee 94-05UsingVersionsingis,ClaudiaBauzerMedeirosandGenevieveJomier 94-06TimesAssncronos:UmaNovaTecnicaparaoFlowShopProblem,Helvio ClaudioL.Lucchesi 94-08Reasoningaboutanotheragentthroughempathy,JacquesWainer 94-07InterfacesHomem-Computador:UmaPrimeiraIntroduc~ao,FabioNogueira 94-09APrologmorphologicalanalyserforPortuguese,JacquesWainer,Alexandre PereiraPeixotoePedroSergiodeSouza delucenaehansk.e.liesenberg 94-12UmaMetodologiadeEspecicac~aodeTimesAssncronos,HelvioPereira 94-10Introduc~aoaosEstadogramas,FabioN.deLucena,HansK.E.Liesenberg 94-11MatchingCoveredGraphsandSubdivisionsofK4andC6,MarceloH.de Peixoto,PedroSergiodeSouza CarvalhoandClaudioL.Lucchesi Farcic 17

19 95-02Adaptiveenumerationofimplicitsurfaceswithanearithmetic,LuizHenriquedeFigueiredo,JorgeStol RelatoriosTecnicos{ Paradigmasdealgoritmosnasoluc~aodeproblemasdebuscamultidimensional,PedroJ.deRezende,RenatoFileto 95-04Agreedymethodforedge-colouringoddmaximumdegreedoublychordal 95-03W3noEnsinodeGraduac~ao?,HansLiesenberg 95-05ProtocolsforMaintainingConsistencyofReplicatedData,RicardoAnido, 95-06GuaranteeingFullFaultCoverageforUIO-BasedMethods,RicardoAnido 95-07Xchart-BasedComplexDialogueDevelopment,FabioNogueiradeLucena, graphs,celinam.h.defigueiredo,jo~aomeidanis,celiapicinindemello 95-08ADirectManipulationUserInterfaceforQueryingGeographicDatabases, N.C.Mendonca HansK.E.Liesenberg andanacavalli 95-11ProcessadordeVizinhancaparaFiltragemMorfologica,IlkaMarinhoBarros, 95-10AHighlyRecongurableNeighborhoodImageProcessorbasedonFunctionalProgramming,NeucimarJ.Leite,MarceloA.deBarros 95-09BasesfortheMatchingLatticeofMatchingCoveredGraphs,ClaudioL. JulianoLopesdeOliveira,ClaudiaBauzerMedeiros 95-12ModelosComputacionaisparaProcessamentoDigitaldeImagensemArquiteturasParalelas,NeucimarJer^onimoLeite RobertodeAlencarLotufo,NeucimarJer^onimoLeite Lucchesi,MarceloH.Carvalho 95-15NP-HardnessResultsforTension-FreeLayout,C.F.X.deMendoncaN.,P VertexSplittingandTension-FreeLayout,P.Eades,C.F.X.deMendoncaN ModelosdeComputac~aoParalelaeProjetodeAlgoritmos,RonaldoParente demenezesejo~aocarlossetubal Eades,C.L.Lucchesi,J.Meidanis 95-17AnaisdaIIOcinaNacionalemProblemasCombinatorios:Teoria,AlgoritmoseAplicac~oes,Editores:MarcusViniciusS.PoggideArag~ao,CidCarvalho 95-16AgentesReplicanteseAlgoritmosdeEco,MarcosJ.C.Euzebio desouza 18

20 95-18AsynchronousTeams:AMulti-AlgorithmApproachforSolvingCombinatorialMultiobjectiveOptimizationProblems,RosianedeFreitasRodrigues, 95-21ALinearTimeAlgorithmforBinaryPhylogenyusingPQ-Trees,J.Meidanis 95-19wxWindows:UmaIntroduc~ao,CarlosNevesJunior,TallysHooverYunes,Fabio 95-20JohnvonNeumann:SuasContribuic~oesaComputac~ao,TomaszKowaltowski PedroSergiodeSouza NogueiradeLucena,HansKurtE.Liesenberg ande.g.munuera CaixaPostal6065 UniversidadeEstadualdeCampinas {Campinas{SP DepartamentodeCi^enciadaComputac~ao IMECC BRASIL