Implementation and Application of Automata

TheSixthInternationalConferenceonImplementationandApplicationof- tomata(CIAA2001)-the?rstoneheldinthesouthernhemisphere-was heldattheUniversityofPretoriainPretoria,SouthAfrica,on23-25July2001. ThisvolumeofSpringer'sLectureNotesinComputerSciencecontainsall thepapers(includingtheinvitedtalkbyGregorv. Bochmann)thatwerep- sentedatCIAA2001,aswellasanexpandedversionofoneoftheposterpapers displayedduringtheconference. Theconferenceaddressedtheissuesinautomataapplicationandimplemen- tion. Thetopicsofthepaperspresentedinthisconferencerangedfromautomata applicationsinsoftwareengineering,naturallanguageandspeechrecognition, andimageprocessing,tonewrepresentationsandalgorithmsfore?cientimp- mentationofautomataandrelatedstructures. Automatatheoryisoneoftheoldestareasincomputerscience. Researchin automatatheoryhasbeenmotivatedbyitsapplicationssinceitsearlystagesof development. Inthe1960sand1970s,automataresearchwasmotivatedheavily byproblemsarisingfromcompilerconstruction,circuitdesign,stringmatching, etc. Inrecentyears,manynewapplicationsofautomatahavebeenfoundin variousareasofcomputerscienceaswellasinotherdisciplines. Examplesofthe newapplicationsincludestatechartsinobject-orientedmodeling,?nitetra- ducersinnaturallanguageprocessing,andnondeterministic? nite-statemodels incommunicationprotocols. Manyofthenewapplicationscannotsimplyutilize theexistingmodelsandalgorithmsinautomatatheorytosolvetheirproblems. Newmodels,ormodi?cationsoftheexistingmodels,areneededtosatisfytheir requirements. Also,thesizesofthetypicalproblemsinmanyofthenewapp- cationsareastronomicallylargerthanthoseusedinthetraditionalapplications. Newalgorithmsandnewrepresentationsofautomataarerequiredtoreducethe timeandspacerequirementsofthecomputation. TheCIAAconferenceseriesprovidesaforumforthenewproblemsand challenges. Intheseconferences,boththeoreticalandpracticalresultsrelatedto theapplicationandimplementationofautomatawerepresentedanddiscussed, andsoftwarepackagesandtoolkitsweredemonstrated. Theparticipantsofthe conferenceserieswerefrombothresearchinstitutionsandindustry. Wethankalloftheprogramcommitteemembersandrefereesfortheire?orts inrefereeingandselectingpapers. Thisvolumewaseditedwithmuchhelpfrom NanetteSaesandHannekeDriever,whiletheconferenceitselfwasrunsmoothly withthehelpofElmarieWillemse,NanetteSaes,andTheoKoopman. VI Foreword WealsowishtothanktheSouthAfricanNRF(forfundingairfares)andthe DepartmentofComputerScience,UniversityofPretoria,fortheir?nancialand logisticsupportoftheconference. WealsothanktheeditorsoftheLectureNotes inComputerScienceseriesandSpringer-Verlag,inparticularAnnaKramer,for theirhelpinpublishingthisvolume. October2002 BruceW. Watson DerickWood CIAA 2001 Program Committee BernardBoigelot Universit'edeLiege,Belgium Jean-MarcChamparnaud Universit'edeRouen,France MaximeCrochemore UniversityofMarne-la-Vall'ee,France OscarIbarra UniversityofCaliforniaatSantaBarbara,USA LauriKarttunen XeroxPaloAltoResearchCenter,USA NilsKlarlund AT&TLaboratories,USA DenisMaurel Universit'edeTours,France MehryarMohri AT&TLaboratories,USA Jean-EricPin Universit'eParis7,France KaiSalomaa Queen'sUniversity,Canada HelmutSeidl TrierUniversity,Germany BruceWatson(Chair) UniversityofPretoria,SouthAfrica EindhovenUniversity,TheNetherlands DerickWood(Co-chair) HongKongUniversityofScience andTechnology,China ShengYu UniversityofWesternOntario,Canada Table of Contents UsingFiniteStateTechnologyinNaturalLanguageProcessingofBasque...1 I"nakiAlegria,MaxuxAranzabe,NereaEzeiza,AitzolEzeiza, andRubenUrizar CascadeDecompositionsareBit-VectorAlgorithms...13 AnneBergeronandSylvieHamel SubmoduleConstructionandSupervisoryControl:AGeneralization...27 Gregorv. Bochmann CountingtheSolutionsofPresburgerEquations withoutEnumeratingThem...40 BernardBoigelotandLouisLatour Brzozowski'sDerivativesExtendedtoMultiplicities...52 Jean-MarcChamparnaudandG'erardDuchamp FiniteAutomataforCompactRepresentation ofLanguageModelsinNLP...65 JanDaciukandGertjanvanNoord PastPushdownTimedAutomata...74 ZheDang,T...