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1 Hermes:NaturalLanguageAccess CarlosB.RiveraandNickCercone toamedicaldatabase TechnicalReportCS March,1998 Regina,Saskatchewan,CANADA DepartmentofComputerScience UniversityofRegina ccarlosb.rivera S4S0A2 ISSN ISBN

2 Contents 3Modules 2Overview 1Introduction 3.1Controlmodules::::::::::::::::::::::::::::::::::::::6 2.2UNIXversion::::::::::::::::::::::::::::::::::::::::5 2.1WWWversion:::::::::::::::::::::::::::::::::::::::4 63 4Parsermodule 3.2Preprocessormodule::::::::::::::::::::::::::::::::::::7 3.3Databaseaccessmodule::::::::::::::::::::::::::::::::::8 5Futureenhancements 4.5Semanticextractor:::::::::::::::::::::::::::::::::::::13 4.4RulesandPrinciples::::::::::::::::::::::::::::::::::::11 4.3UnicationandSubsumption:::::::::::::::::::::::::::::::11 4.1HPSGgrammarandlexicon::::::::::::::::::::::::::::::::10 4.2AVM:::::::::::::::::::::::::::::::::::::::::::::

3 cadecus.theinterfacestrivestoimprovethecommunicationbetweentheuserandthedatabase, ThenewinterfaceisnamedHermes,inrecognitionofhisabilityasamessengerandhissta,the ThisprojectwasjointlyfundedbytheIRIS2HMI-2projectandtheIRISCentresofExcellence. 1Introduction similarlytohermesbetweenmortalsandgods.thecadecusiswidelyusedasasymbolforthe ThisdocumentdescribesaNLIDB(naturallanguageinterfacetodatabases)formedicaldatabases. TheinterfacediscussedwasdesignedandimplementedattheUniversityofReginabasedpartially onearlierworkdoneonsystemxatsimonfraseruniversity[chj+90,chm+94,mc91,vpc93]. medicalprofession. intoanintermediateform.thisintermediateformisthentranslatedintosqlthatcanthen usedintheparserwasoriginallydevelopedbyshintamayasari[may95,may96a,may96b]andhas undergoneextensivemodications[riv98]. thedatabaseschemaoraformaldatabasequerylanguage.thishighlevelviewwouldmodelwhat berunonthemedicaldatabasedesignedbyweidongyu[yu96].hpsgisacombinedsemantic andsyntacticformalismthathandlessentences,phrasesandwords.thegrammarandlexicon HermesusesanHPSGbasedparsertotranslatetheusersad-hocnaturallanguage(NL)queries ahospitaladministratorwouldwant.thefollowingqueriesaresamplesofwhathermeshandles: Givemethenameoftheheadofradiology. Listpatientsseenbyheadofradiology. OceandhomephonenumberforDr.JaneAebig. Hermes'goalistoallowausertoaccessthedatabasefromahighlevelwithoutknowingeither Totalnumberofpediatricians. Averageageofallpatientsseenbyfemalesurgeons. Dr.Aebig'stitle. preprocessoranddatabaseaccessmodules.section4describesthehpsgparserandsemantic twoversionofhermespresentlyimplemented.section3givesdetaileddescriptionsofthecontrol, insection3.3. andthereginahealthdistrictandreectwhatahealthcarefacilitywouldhave.thetablescovered byhermesaredoctorandpatientdemographicinformation,patientweightandheightdata,patient allergies,insurancecoverageinformationandvisitinformation.thedatabaseisfurtherdescribed Theremainderofthisdocumentisdividedintofoursections.Section2givesanoverviewofthe ThedatabaseHermesconnectstowasmodelledafterthedatabasesmaintainedbySaskHealth givessamplenlqueriesthesystemhandles. 2Overview TherearetwoversionsofHermespresentlyimplemented,anSGIUNIXversion(Hermes:UNIX), extractorthathandlesconvertingfromnltosql.section5givesplannedfutureenhancements theuserinteractswiththroughmenus,andaworldwideweb(www)version(hermes:www), forhermes.thispaperconcludeswithtwoappendicesthatshowahermesexecutiontraceand theuserinteractswiththroughformsonwebpages.bothversionsofhermesarecomposedoffour 3

4 Figure1:Hermesdesign Internet Socket Control client server Parser SQL Prepare query aserverrunningonthefastestavailablecomputer,sinceparsingcanbeaverycomputationally intensiveoperation.thecontrolprogramhasaclientstubbuiltintoitthatconnectstothisserver. intermediateformattosqlexecutablebythedatabaseaccessmodule.theparsermoduleis languagetoanintermediateformatrequiredbytheparser.theparsermoduleconvertsfromthe modulesofhermesasneeded.thepreprocessorchangestheuserenteredqueriesfromnatural modules:control,preprocessor,parseranddatabaseaccess.thesemodulesandtheirconnections areshowninfigure1. Thecontrolmodulehandlesuserinputandoutputandcallsroutinestoaccesstheotherthree Preprocessor Database access ThecontrolprogrampassestheintermediateformatandreceivesbackallvalidSQLstringsforthe thethreepagescomprisingwwwhermes(notshownisthepagegeneratedwhenthereisan query.thedatabaseaccessmoduletakesansqlstringandaccessesweidong'smedicaldatabase. error). Netscape,Explorer)athttp:// ThisdatabaseisanOracledatabaserunningonZeus,anSGIChallengeLparallelcomputer. mes:wwwinvolvedintegratingfourprogramminglanguages:c,prolog,perlandhtml.using 2.1WWWversion TheWWWversionofHermesisaccessiblefromanybrowserthathandlesform(e.g.Lynx, pheswithspacesandremovesallperiodsfromthequery.themodiedqueryisthenpassedtoac programwhichfunctionsasthecontrolmoduleforthewwwversion,callingthepreprocessorand parser.theoutputfromtheparserischeckedtoseeifanyerrorsoccurred.iftherearewereany errors,thesearereturnedtotheperlscriptandthecprogramexits.otherwise,thesqlqueries theformshowninfigure2theuserenterstheirnlquery.thisnlqueryispassedtoaperlscript tobeextractedfromtheformatoutputtedbythewwwform.thisscriptreplacesanyapostro- Figure5showstheprogramsandowofinformationforHermes: returnedbytheparseraresortedandduplicatesremoved.theremainingsqlqueriesarereturned totheperlscript.thescriptchecksiftherewereerrormessagesandifsocreatesawebpageto Aebig.TherearetwoSQLqueriesshownbecausetheparserwasunabletodecidewhethertheuser wantedthepatientordoctordemographictabletobequeriedforjaneaebig.theselectedsql displaytheerrormessagesandalinktoerrormessagehelp.iftherewerenoerrorsreturned,the Thepagealsohasaradio-button(one-of-many)formshowingtheSQLqueriesandpromptingthe usertoselectonetorun.figure3showsthispageforthenlquery,phonenumbersforjane scriptwillgenerateawebpageshowingthetotalnumberofparsesandnumberofuniqueparses. 4

5 resultscanbesavetoaleusingcutandpastefromthewwwbrowserwindow. 2.2UNIXversion queryispassedtoanotherperlscriptwhichcallsastand-aloneversionofthedatabasemoduleto runthequery.thequeryresultsaredisplayedonanadditionalpage,asshowninfigure4.the Figure2:HermesWWWenterNLpage TheHermes:UNIXoersmorefunctionalitythantheWWWversion.Thebeginningusercanenter NLqueriesandtheexperiencedusercanenterSQLqueries.Thedatabaseresultscanbesavedto showsasamplerunfortheunixversionofhermes. versionthroughon-screenmenus.themainandhelpmenusareshowninfigure6.appendixa aledirectlyfromhermes.thereisextensiveon-linehelpavailable.theuserinteractswiththis userentersanlorsqlquery ifqueryisnlthenitispassedtopreprocessorthentoparser resultantsqlstringsaredisplayedfortheuser,ifmorethenonesqlstringisgeneratedthe ThenormalorderofaqueryinHermes:UNIXwouldbe: usercaneitherchoosetorenethequerybyenteringanewnlorsqlqueryorrunthe userispromptedtoselectone 5

6 3Modules Thecontrol,preprocessoranddatabaseaccessmodulesaredescribedinthissection.Theparser moduleisthemostcomplicatedmoduleinhermesandiscoveredinsection4. Figure3:HermesWWWchooseSQLpage 3.1Controlmodules Therearetwoversionsofthecontrolmodule,oneforHermes:WWWandoneforHermes:UNIX. Thetwoversionsharecommoncode(theclientstubfortheparserserver)butneedtobecompiled separately.thecontrolmoduleinhermes:wwwiscomprisedofthetwoperlscriptsandc programshowninfigure5.theinteractionandfunctionoftheseprogramsweredescribedin Section2.1.ThecontrolmoduleinHermes:UNIXisaCprogramthathandlesdisplayingthe mainandhelpmenus,acceptinguserinputinnlorsqlandformenuchoices,sortingand IftheuserselectsandentersanSQLquery,thenthecurrentSQLqueryissettothis.Theuser removingduplicatesqlstringsreturnedbyparser,printingtheuniquesqlstringsandhandling userselectionofsame. fromthemainmenu.iftheuserselectsandentersannlquery,thisispassedtothepreprocessor. Thepreprocessorwillreturntheformatrequiredbytheparser.Thisisthenpassedtotheparser. TheparserreturnsanSQLforeveryparseitgenerates.Inmostcaseseventhoughthereismore cantheneitherdisplayorrunthisquerydirectlybychoosingviewsqlorrunsqlrespectively Thecontrolmodulestartsobyprintingthemainmenuandwaitingforselectionfromtheuser. 6

7 alluniquesqlqueriesaredisplayedandtheuserispromptedtoselectonetosetthecurrentsql queryto.afterthistheusercanchoosetovieworrunthissqlquery.iftheuserchoosestorun SQLqueries.IfthereisonlyoneSQLquerythenthecurrentSQLqueryissettothis,otherwise queriesandremovesanyduplicates.theprogramwillreportthenumberofparsesandunique thanoneparsethesemanticcontentisthesame.therefore,thecontrolprogramsortsthesql Figure4:HermesWWWdatabaseresultspage thisquerythenthecurrentsqlqueryissenttothedatabaseaccessmodule. 3.2Preprocessormodule convertingnaturallanguagequeriesintotheformatexpectedbytheparser.theparserisprolog ThetwoversionsofHermesusethesamepreprocessormodule.Thepreprocessormodulehandles basedandthereforeexpectsaprologlistofatoms.thismeansthatthequerymustbeenclosed periodmustappearaftertheclosingbracket.figure7showsanunconvertedandconvertedphrase. Thepreprocessoralsoremovesallwhitespace.Theparserhasasingleword,s,torepresentthe insquarebracketswitheachwordinallsmallcharactersandseparatedbycommas.aswell,a nothandleperiods,sotheperiodsafteranabbreviationsuchasmrordrorattheendofaquery areremovedwhenconvertingfromtheinputquerytotheintermediateform.thepreprocessor possessive's,thereforeapostrophesintheinputqueryarereplacedbycommas.theparsercan moduleiswritteninc,althoughtherstperlscriptcalledinhermes:wwwremovesperiodsand changingapostrophetospacestofacilitatepassingthenlquerytothecprogram. 7

8 UNIX WWW Perl C NL query NL query Hermes NL query Perl C Preprocformat test script program parser essor page SQL queries or Errors format Errors SQL queries parser SQL queries or Errors Error 3.3Databaseaccessmodule page Parser ThetwoversionofHermesusethesamedatabaseaccessmodulewithminormodicationsfor SQL Prolog display SQL query page SQL Thedatabaseaccessmoduleiscalledwhentheuserwantstoexecutetheirdatabasequery.The Hermes: Figure5:WWWHermesdesign databasemodulewaswrittenbyweidongyuandhandlesansqlquerystoredinacharacter thatitcanberunasastand-aloneprogramandhasthesavingtoalefunctionalitydisabled. Perl Database script access string.thedatabaseisfullydetailedin[yu96].thismodulenormallypromptstheuserbefore Results results Results runningtheactualdatabaseaccesstoseeiftheresultsshouldbesavedtoaleordisplayedonthe page screen.thedatabasemodulehandlesthecreationandllingoftheleifthatiswhattheusers manual): ALLERGIESThistablecontainsallergiesforpatients(e.g.milkallergy,penicillinallergy). mostinterestingisused.hermescanaccessthefollowingtables(whicharedescribedinweidong's selects. DOCTORSThistablecontainsdemographicinformationfordoctors(e.g.rstandlastname, Hermescannotaccesseverytableinthedatabase.Insteadasubsetofthedatabasejudged DEMOGRAPHICSThistablecontainsdemographicinformationforpatients(e.g.address, INSURANCESThistablecontainsinsuranceinformationforpatients(e.g.insurancenumber VISITThistabledescribesvisitmadebypatientstodoctors(e.g.referringdoctor,attending speciality,age). doctor,admittanceanddischargedates).8 maritalstatus,gender). andtype).

9 1Enternewquery 2EnterSQL 3ViewSQL 4RunSQL 5Help 6Exit Selection? Hermesmainmenu =========== Hermeshelpmenu ========== 1Generalhelp 2Enternewqueryhelp 3EnterSQLhelp 4ViewSQLhelp 5RunSQLhelp 6Databaseschemahelp 7Errormessagehelp 8Aboutmessage 9Exithelp Originalphrase:Givemetheocephonenumberandaddressoftheheadofradiology. Figure6:Hermesmenus Selection? WEIGHTHEIGHTThistablecontainsweightandheightinformationforpatients(e.g.weight, Convertedphrase:[give,me,the,oce,phone,number,and,address,of,the,head,of,radiology]. Hermesallowsallowsnon-joinandjoinqueriestobeexecutedonthesetables.Non-joinqueries height,date). Figure7:Preprocessedquery accessonlyonetable,forexample: Joinqueriesallowuptothreetablestobejoined,forexample: Lastnamesforfemaleradiologists. NamesforpatientsinRegina. Agesofpatientsseenbyheadofradiology. PatientsseenbyDr.Aordable. Dr.Aebig'sspecialty. Addressesforallpatientsseenbyfemaleradiologists. Phonenumbersforfemalepatients. limitsthenumberofcolumnsselectedwithaggregatefunctions,butdoesnotchecktomakesurea selectedcolumnisnumeric.thefollowingaresamplequeriesinvolvingaggregatefunctions: Thesequeriescanincludetheaggregatefunctions:averageandcount.TheHermesparser TotalnumberofsurgeonsinRegina. AverageageofpatientsseenbyDr.MaryAebig. 9

10 TheparsermoduleisthemostcomplicatedmoduleinHermes.Itspurposeistoconvertfroma 4Parsermodule naturallanguagephraseenteredbytheusertoanexecutablesqlquery.theparsermoduleuses compilegram/1predicateisusedtocompilethegrammarandlexicondescribedin[riv98].the (ALE)Prologprogram.ALE\isanintegratedphrasestructureparsinganddeniteclauselogic andmanipulationoftypes,whichareusedintheattributevaluematrices(avm),usedinhpsg tostoresyntacticandsemanticknowledgeaboutwordsandphrases[ps87,ps94].theale theprologprogramminglanguageandabasicunderstandingofprologisrequiredforthefollowing grammarcontainsthealerulesthatformahpsg-basedparserplussemanticruleshardcodedfor section.thefollowingaregoodprologreferences[bra90,cm84,ss86]. thehealthdatabase.thelexiconcontainapproximately300words,halfofwhichhaveassociated programmingsysteminwhichtermsaretypedfeaturestructures"[cp94].aleallowscreation Tocreatetheparsermodule,SicstusProlog2.1#9isloadedwiththeAttributeLogicEngine ansqlqueryforeachparse.figure8showstheparserconguration. parsermodulelistensataninternetsocketforincomingphrases.theoutputbacktotheclientis semanticcontent,coveringourhealthcaredatabase.aprologprogram,thesemanticextractor,is loadedtotranslatefromtheoutputfromthealerec/4predicatetoansqlquery.theresulting queries.aprecedingtechreportonhermes[riv98]hasamorecompletecoverageofthistopic. TherearegoodtutorialontheHPSGformalismavailableontheWorldWideWeb[Man96,Mat97, ThissectiongivesanoverviewoftheHPSGgrammarandlexiconusedinHermestoparseNL 4.1HPSGgrammarandlexicon Figure8:Parserconguration Matrices(AVM);themethodusedtojoinwordsintophrases,unicationandsubsumption;and 4.2AVM therulesandprinciplesusedtocontrolwhatwordsarejoined. ThedatastructurecentraltotheHPSGformalismistheAVM.AnAVMisafeaturestructurethat representsasign.asignisalexicalentry(word),phraseorasentence.figure9showstheavm Sag95].ThemainpartsoftheHPSGformalismare:thecentraldatastructure,AttributeValue thereareseveralsortsaheadcantake,suchasnoun,verboradjective.thevalueforanattribute istheattributeorlistofattributesindentedbelowitsname.valuesareeithersimple(oratomic), likeophone,whichisthevalueoftheattributehd,orcomplex.complexvaluesincludelists,such ascolumnslistorsynsemlist;sets,whicharenotimplementedinthehermesgrammar;oranother resultingfromparsingocephonenumberfortheheadofradiology.thewordsincapitalsare attribute(alsocalledfeatures),followedbytheirsorts.sortslabeltheattributevalues,forexample, AVM,forexamplethevalueforMODinanAVMforanadjectiveisanAVMrepresentingcommon nouns.theavmshowninfigure9istherstofsixdistinctparsesgeneratedbytheparser.each parsecontainsthesamesemanticinformationbuthasdieringsyntacticinformation. 10 semantic server lexicon ALE Sicstus extractor

11 asvalues.thecatattributetakesfourattributesasvalues:head,partofspeechinformation forwordorheadofphrase;marking,usedinconjunctions(e.g.andandor)andcomplements mationfortheheadofsign,andcont,whichcontainsthesemanticinformationforthesign, (e.g.forandthat);spr,alistofsignsthatcorrespondtospeciersthewordorphrasecantake asobjects(e.g.atransitiveverbwouldtakeanounorprepositionalphrase). (e.g.determinersforcommonnouns)andsubcat,alistofavmsthewordorphrasecantake TheCONTattributetakesthefollowingattributesasvalues:ACTION,QUERY,REFand TheLOCattributeofanAVMtakestwoattributesCAT,whichcontainsthesyntacticinfor- composedofthetableandcolumnsattributes.thetableattributesortsrepresentingthe tablesinthedatabasethathermescanaccess(e.g.doctorsrel,visitrel).thecolumnattribute selected,thewhereconditionsandthetablesselectedforthequery.thequeryattributetakes asingleobjectinthequerylistmeansthatatablejoinisrequired.thequeryobjectsare alistofqueryobjects.theseobjectseachrepresentasingletable,thereforehavingmorethan SEMMARK.TheACTIONattributecontainsthedatabaseactionrequired(e.g.sum,count, isalistofobjectsthatcontrolswhatwhereconditionsaresetforthenalquery.thehdvalueof eachelementinthislisthasasortthatselectsthecolumnstheuserwantsdisplayed(e.g.ophone average)andhasadefaultvalueofdbaction.thequeryattributecontrolsthecolumns infigure9).theobjectsinthecolumnsattributearealistofattributescorrespondingto thecolumnsthatcanberestrictedforthecurrenttable.thewhereconditionsaresetwhenthe Unicationisthejoiningoftwostructures(partialorwhole)intoasinglestructurethatcontains 4.3UnicationandSubsumption usedtocontrolwhatphrasesprepositionscantakeandsemmarkattributeisusedinselecting whattypeofnounscanbeusedinnominalcompounds(e.g.ocephonenumber). valueforoneoftheseattributesisnotdval.forexamplefromthegure,therearetwowhere nomoreorlessinformationthantheoriginaltwostructures.subsumptionistheorderingof conditionsset:depteqarg1radiologyandtitleeqarg1director.therefattributeis anotherwhencreatingtheresultantavm.unicationfailswhenneitheroftwovaluesforthesame attributeintheinputavm,subsumestheothers(e.g.singandplurfornumattribute). theattributesandvalues.thismeansthatsomevaluesandattributearemoregeneralorspecic thanothers.forexample,thevaluefornuminfigure9issettonumthemostgeneralvalue. Thisvaluewouldsubsumeavalueofsing,sincesingismorespecic.Unicationcreatesthemost valuesfromgeneraltomorespecic.thehpsgformalisminsistsonatherebeinganorderto 4.4RulesandPrinciples ThegreatstrengthofHPSGisthelimitednumberofschemas(rules)andprinciplesusedtojoin generaldescriptionthatiscompatiblewiththetwoinputs.unicationsubsumesonevaluewith createlargersigns.therearesixschemasoutlinedinthehpsgformalismtohandledierenten- glishgrammaticalstructures:head-subject,head-complement,head-subject-complement,head- Marker,Head-AdjunctandHead-Filler.HermeshasalloftheseschemasexcepttheHead-Marker (determiners). Schema1(Head-SubjectSchema)Thisschemalicencessaturatedphraseswithaphrasalhead andhead-fillerschemas,aswellastwoadditionalschemastohandleconjunctsandspeciers wordsintophrasesandsentences.theserulesandprinciplescontrolhowsignsarejoinedto daughterandoneotherdaughterthatisacomplement.anexamplewouldbethesentenceshe 11

12 phrase SYNSEMsynsem LOCloc CATcat HEADnoun AGRagr NUMnum PERSONpers CASEcase MODnone MARKINGmarking SPRsynsemlist SUBCATelist CONTcont ACTIONdbaction QUERYnequerylist HDquery COLUMNSnecolumnslist HDophone AGEdval ARG1valtype CITYdval ARG1valtype DATEOFBIRTHdval ARG1valtype DEPTeq ARG1radiology FNAMEdval ARG1valtype LNAMEdval ARG1valtype PROVdval ARG1valtype SEXdval ARG1valtype SPECIALITYdval ARG1valtype TITLEeq ARG1director TLcolumnslist TABLEdoctorsrel TLquerylist REFdbref SEMMARKdeptnamedc Figure9:ExampleAVM walks.theverbwalksistheheaddaughterandsheistheotherdaughterthatcomplements walks. Schema2(Head-ComplementSchema)Thisschemalicensesphrasesthathavealexicalhead daughter(awordratherthanaphrase)andzeroormorecomplementdaughters.these daughtershavesatisedalltheirsubcategorizationrequirementsexceptthesubject.the phraseisadoctorislicensedbythisrule.theverbisisthelexicalheaddaughterandthe nounphraseadoctorthecomplementdaughter. Schema3(Head-Subject-ComplementSchema)Thisschemalicensessaturatedphrases with`subject-auxiliaryinversion'clauses.thisschemarequiresverbstohaveanadditional HEADsubattributeINVwhichtakesthevalue+or-.A+meanstheverballowsinverted structures(e.g.cankimgo?).additionallytheheaddaughterinthisschemamustbea lexicalsign(aword). Schema5(Head-AdjunctSchema)Thisschemalicencesphraseswithanadjunctdaughter andheaddaughteritselects.adjunctsinhpsghavetobeofsortsubstantivesincefunctional sortsarehandledbyschema4.themodvalueoftheadjunctisstructuresharedwiththe SYNSEMvalueoftheheaddaughter.Thisschemalicencesmodifyingwords(adjectives, adverbs)andthewordstheyaremodifying(nouns,verbs).anexamplephrasewouldberst name,whererstistheadjunctandnametheheaditmodies. 12

13 Specier-HeadSchemaThisschemalicencesphraseswithaspecierdaughterandthehead ConjunctSchemaThisschemalicencesphrasesconsistingoftwodaughtersseparatedbyaconjunction.ThetwodaughtershavetohavethesameHEAD,SUBCATandSPRvalues.An daughteritselects.thespecierdaughterhastohaveaheadsortofdet(erminer).an examplewouldbethephrasethedoctor. denedinhermeshasthefollowinguniversalprinciplesthathandlemostenglishgrammatical structures. andsemanticrulesbutalsoincludesprinciplesthatcoverotherlanguages.thehpsggrammar TheHPSGformalismoutlinesmanyuniversalprinciplescoveringnotonlyEnglishgrammatical examplewouldbethephrasedoctorsandsurgeons. SubcatprincipleTheSUBCATvalueofanyheadedphraseistheconcatenationofthelistvalues SpecierprincipleInaheadedphrase,wherethedaughterhasaHEADvalueofsortfunctional, HeadfeatureprincipleTheHEADvalueofanyheadedphraseisstructure-sharedwiththe MarkingprincipleTheMARKINGvalueofanyheadedphraseisstructure-sharedwiththe HEADvalueoftheheaddaughter. ofthesynsemvaluesofthecomplement-daughters. ThisprinciplewasadaptedtohandleWeidong'smedicaldatabase,butcouldbeeasilymodied tohandleanyrelationaldatabase.thesemanticprincipleworksbyindividuallycombiningthe ThesemanticprincipleusedinHermeshandlesunifyingtheCONTvalueofphraseorwords. MARKINGvalueofdaughterifany. thespecvalueofthatvaluemustbestructure-sharedwiththephrasessynsemvalue. becausethereareseveralcasesthatmustbecovered.first,thetableandcolumnsattribute semanticheaddaughter.unifyingthequeryattributeforwordsorphrasesinvolvesmorework principlefails.thismeanstryingtojointhewordsaverageandsumwillfail,butaverageand weightwillnotsincetheactionattributeforweightisundened.thesemmarkattributeis inheritedfromthesemanticheaddaughterexceptforprepositionalphraseswhereitisobtainedby unifyingthesemanticheadandcomplementdaughters.therefattributeisinheritedfromthe ACTIONattributeofthesemanticheadandcomplementdaughtersmustbeuniableorthis ACTION,SEMMARK,REFandQUERYattributesforthewordsorphrasesbeingjoined.The sameforbothsigns(orifoneisundened).iftheunicationfailsthenthetableattributes forthetwosignareunied(againonlyiftheyhavethesamevalueoroneisundened)andthe COLUMNSlistofthemotherisformedbyconcatenatingtheCOLUMNSlistofonesigntothe COLUMNSlistoftheothersign.IftheTABLEunicationfailsthismeansthattheTABLEvalue ofthetwosignsaredierentandatablejoinisrequired.thetablevaluesofthetwosignsare comparedtomakesuretheyhaveacommonattribute(e.g.thedea#attributeinthedoctor tableandtherefphysicanattributeinthevisittable).iftheydohaveacommonattribute forthetwosignsareunied.thiswillonlysucceedifthetableandcolumnsvaluesarethe ThesemanticextractorisaPrologprogramconsistingofapproximately700linesofcommented thanthequeryvalueofthemotheristheconcatenationofthequerylistforonesignandthe QUERYlistoftheothersign. 4.5Semanticextractor codeand38predicates.thesemanticextractorhandlesconvertingfromtheintermediateformat 13

14 returnedbythehpsgparsertoanexecutablesqlstring.theintermediateformforthequery valuesarenotusedinconvertingfromtheintermediateformtosqlsotheyarealsodiscarded). OcephonenumberfortheheadofradiologyisshowninFigure10.Thisformusesnestedstructures toconveythesameinformationshowninfigure9. QUERYandACTIONvaluesarethenextractedfromtheCONTvalue(theREFandSEMMARK valueisnotpresentlyusedinconvertingfromtheintermediateformtosqlsoitisdiscarded).the ThesemanticextractorrstextractstheCONTvaluefromtherestoftheAVM(theCAT phrase(1100-synsem(1095-loc(1089-cat(1081-noun(1074-agr(1068-num,1065-pers),1062- nequerylist(1030-query(1024-necolumnslist(1018-ophone(1001-dval(996-valtype),993- dval(988-valtype),985-dval(980-valtype),977-eq(972-radiology),969-dval(964-valtype),961- dval(924-valtype),921-dval(916-valtype),913-dval(908-valtype),905-eq(900-director)),897- columnslist),894-doctorsrel),891-querylist),888-dbref,885-deptnamedc)))) case,1059-none),1056-marking,1053-synsemlist,1050-elist),1047-cont(1039-dbaction,1036- dval(956-valtype),953-dval(948-valtype),945-dval(940-valtype),937-dval(932-valtype),929- elementinthislist.thelabelforthestructuresinthelististhetablebeingaccessed(e.g.doctor aboutthecurrentquery.thisstructureisalistofstructures,witheachstructurecontainingquery informationforasingledatabasetable.therefore,ajoinisrequiredifthereismorethanone accessed.whileextractinginformationfromthislistastructureiscreatedtostoreinformation ThelistcomposingtheQUERYvalueisdecomposedtondthenumberoftablesthatarebeing Figure10:Intermediateform [demographics([],[demographics.sex='f']),doctors([],[doctors.l_name='aebig']) ordemographics)andeachstructuretakestwoarguments.therstargumentisalistcontaining,visit([],[])] andforthephrasefemalepatientsseenbydr.aebig: theselectedcolumnsandthesecondargumentisalistcontainingthewhereconditions.anexample structureforthephrasenamesoffemalesurgeonsis: AfterthenumberoftablesbeingqueriedisfoundtheTheTABLEandCOLUMNSvaluesforeach tableareextracted.thetablenameisconvertedfromthevaluesinthegrammartothetablename [doctor([doctor.f_name,doctor.l_name],[specialty(eq,surgeon),sex(eq,female)])] inthedatabase(e.g.doctorsreltodoctors).theparsercanreturnanavmwherethereisno TABLEvaluespecied(e.g.forthewordname).Thesemanticextractorpresentlygeneratesan errormessagewhenthereisnotablevaluespecied. thesignsthewhereconditionscanbeineitherorbothelements.thesewhereconditionsare table(see[doctor.f_name,doctor.l_name]above).dependingwhichrulewasusedtojoin conditionsforthecurrenttable.eachelementisextractedseparatelyanditsvaluesaddedto andonewithahdvalueofheight.theselectedcolumnsareconcatenatedwithaperiodto theendoftheconvertedtablenameandinsertedintotherstlistargumentforthecurrent weightandheight)willhavetwoelementsinitscolumnslist,onewithahdvalueofweight thestructureforthistable.aquerywithmultipleselectedcolumnsfromthesametable(e.g. TheCOLUMNSvalueisalistwitheachelementcontainingtheselectedcolumnsandwhere extractedandconvertedtothestructuresshowninthesecondlistargumentforthecurrenttable (see[specialty(eq,surgeon),sex(eq,female)]above). 14

15 thathandlesprintingthesqlstring.first,acheckismadetoseeiftherearenoselectedcolumn inanyofthepassedtables(e.g.inanunder-speciedquerysuchasfemaledoctors).ifthereareno ofcolumnsisselectedanerrormessageisprinted.thetablename,selectedcolumnsandwhere selectedcolumnsthendefaultcolumnareassigned.iftheactionattributehasavalueassigned conditionsforalltablesarecombinedintoasinglelistforeach.thelistissortedtofacilitate acheckismadethatonlyoneornone(asneeded)columnsareselected.ifthewrongnumber ndingtheuniquesqlstringsinthecontrolprograms.theselectedcolumnsandtablesarethen AfterthestructurehasbeencompletelybuiltfromthepassedAVMitispassedtothepredicate printed.printingthewhereconditionsinvolvesslightlymoreworksincetherecanbenowhere conditionstoprint(e.g.lastnameofalldoctors)andajoinconditionmustbeaddedforalltables inthetablelistthathaveacommoncolumn(e.g.visit.referring_doctor=doctors.dea#). ContinuedexpansionofthelexiconTheexistingHermeslexiconcontainsapproximately300 ThefollowingenhancementsareplannedforHermes: 5Futureenhancements DierentlexiconsanddatabasesAbilitytoconnecttodierentlexiconsanddatabases(there coverageofalltheinformationcontainedinthemedicaldatabase. words.thesewordsaremostlyspecictothemedicaldomainbutdonotyetgivegood SavefeaturesAddingtheabilityto\can"(savequeries)inHermes:UNIXwouldgreatlyenhance willneedtobeadierentlexiconforeachdatabase,sincethelexiconcontainsdatabase specicinformation).majorportionsofthelexiconwillbere-usablethoughsincewordshave nospecicdatabaseconnotations(e.g.is,a,pronouns). theusabilityofhermes. 15

16 References [Bra90]I.Bratko.PrologProgrammingforArticialIntelligence.Addison-Wesley,second [CHJ+90]N.Cercone,G.Hall,S.Joseph,M.Kao,W.Luk,P.McFetridge,andG.McCalla. [CHM+94]N.Cercone,J.Han,P.McFetridge,F.Popowich,Y.Cai,D.Fass,C.Groeneboer, edition,1990. ArticialIntelligenceinSoftwareEngineering,pages169{250.JAIPress,Greenwich, Conn.,1990. G.Hall,andY.Huang.SystemXandDBLearn:easilygettingmorefromyourRelationalDatabase.IntegratedComputer-AidedEngineering,1(4):311{339,1994. edition,1984. NaturalLanguageInterfaces:IntroducingSystemX.InT.Oren,editor,Advancesin [Man96]SureshManandhar.ACourseonHPSGgrammarsandtypedfeatureformalisms.Lan- [CM84]W.F.ClocksinandC.S.Mellish.ProgramminginProlog.Springer-Verlag,Berlin,2nd [CP94]BobCarpenterandGeraldPenn.ALE:TheAttributeLogicEngineUser'sGuide. Version2.0.1,December1994. [Mat97]ColinMatheson.HPSGGrammarsinALE.UniversityofEdinburgh, [May95]ShintaMayasari.AnHPSGLexiconforaPhysicalActivityDatabase.TechnicalReport guagetechnologygroup,humancommunicationresearchcentre,universityofed- inburgh, [May96a]ShintaMayasari.ANaturalLanguageInterfacetoaPhysicalActivityDatabase:Design CS-95-09,ComputerScienceDepartment,UniversityofRegina,September1995. writing/,1996. [May96b]ShintaMayasari.AnOverviewofSystemY.UniversityofRegina,Fall1996.This anditsimplementation.universityofregina,summer1996. [PS87]CarlPollardandIvanA.Sag.Information-BasedSyntaxandSemantics,Volume1: [MC91]P.McFetridgeandN.Cercone.InstallinganHPSGParserinaModularNaturalLan- Fundamentals.CSLILectureNotes13,Standford:CenterfortheStudyofLanguage guageinterface.incomputationalintelligenceiii,pages169{178.northholland,am- sterdam,1991. paperisincomplete. [PS94]CarlPollardandIvanA.Sag.Head-DrivenPhraseStructureGrammar.TheUniversity [Sag95]IvanSag. [Riv98]CarlosB.Rivera.Hermes:GrammarandLexicon.Technicalreport,Universityof andinformation, Regina,March1998. ofchicagopress,1994. MaterialsforteachingHPSG. 16 StanfordUniversity,

17 [SS86]L.SterlingandE.Shapiro.TheArtofProlog:AdvancedProgrammingTechniques.The [VPC93]C.Vogel,F.Popowich,andN.Cercone.LogicBasedInheritanceReasoning.InMorris [Yu96]WeidongYu.DocumentofProject:NaturalLanguageInterfacetoHealthcareDatabase MITPress,Cambridge,Massachusetts,2ndedition,1986. Sloman,editor,ProspectsforArticialIntelligence.IOSPress,1993. (databasepart).universityofregina,september

18 Allrightsreserved. AppendixA-Samplerun ThefollowingisasamplerunofHermes: zeus[1]%hermes Hermes1.0;March1998 Copyright(C)1997,1998CarlosRiveraandNickCercone 3ViewSQL 2EnterSQL 4RunSQL 5Help 6Exit Selection?1 1Enternewquery Hermesmainmenu =============== 1) SELECTdoctors.h_phone,doctors.o_phone Theuniqueparse(s)are: Parsing... Doneparsing! Therewere3parsesreturnedbytheparserofwhich1areuniqueSQLstrings. Enternewquery:phonenumberfortheheadofradiology FROMdoctors WHEREdoctors.dept='RADIOLOGY'anddoctors.title='DIRECTOR' SettingtheSQLqueryequaltotheSQLreturnedbytheparser! 3ViewSQL 2EnterSQL 4RunSQL 5Help 6Exit Selection?4 1Enternewquery Hermesmainmenu =============== Yourchoose: H_PHONE Inputafilename:outputtotheassignedfile. Press<ret>key:outputtoscreen. O_PHONEOUTPUTOFANSWERS 18

19 1rowprocessed.Hermesmainmenu ViewSQL 2EnterSQL 4RunSQL 5Help 6Exit Selection?1 1Enternewquery =============== 1) SELECTdemographics.phone Theuniqueparse(s)are: Parsing... Doneparsing! Therewere4parsesreturnedbytheparserofwhich2areuniqueSQLstrings. Enternewquery:phonenumbersforJaneAebig FROMdemographics WHEREdemographics.f_name='JANE'anddemographics.l_name='AEBIG' 2) SELECTdoctors.h_phone,doctors.o_phone FROMdoctors WHEREdoctors.f_name='JANE'anddoctors.l_name='AEBIG' PleaseselecttheSQLqueryyouwanttorun:2 3ViewSQL 2EnterSQL 4RunSQL 5Help 6Exit Selection?3 1Enternewquery Hermesmainmenu =============== FROMdoctors WHEREdoctors.f_name='JANE'anddoctors.l_name='AEBIG' SELECTdoctors.h_phone,doctors.o_phone CurrentSQLstringis: 2EnterSQL 1Enternewquery Hermesmainmenu =============== 19

20 3ViewSQL 4RunSQL 5Help 6Exit Yourchoose: Selection?4 H_PHONE Inputafilename:outputtotheassignedfile. Press<ret>key:outputtoscreen. O_PHONEOUTPUTOFANSWERS 0rowsprocessed.Hermesmainmenu 3ViewSQL 2EnterSQL 4RunSQL 5Help 6Exit Selection?1 1Enternewquery =============== 1) SELECTdemographics.phone Theuniqueparse(s)are: Parsing... Doneparsing! Therewere4parsesreturnedbytheparserofwhich2areuniqueSQLstrings. Enternewquery:phonenumbersforJaneAebig FROMdemographics WHEREdemographics.f_name='JANE'anddemographics.l_name='AEBIG' 2) SELECTdoctors.h_phone,doctors.o_phone FROMdoctors WHEREdoctors.f_name='JANE'anddoctors.l_name='AEBIG' PleaseselecttheSQLqueryyouwanttorun:1 3ViewSQL 2EnterSQL 1Enternewquery Hermesmainmenu =============== 20

21 4RunSQL 5Help 6Exit Yourchoose: Selection?4 PHONE Inputafilename:outputtotheassignedfile. Press<ret>key:outputtoscreen. OUTPUTOFANSWERS rowprocessed.Hermesmainmenu 3ViewSQL 2EnterSQL 4RunSQL 5Help 6Exit Selection?5 1Enternewquery =============== 7Errormessagehelp 4ViewSQLhelp 3EnterSQLhelp 5RunSQLhelp 6Databaseschemahelp 1Generalhelp 2Enternewqueryhelp Hermeshelpmenu 8Aboutmessage =============== 9Exithelp accessthedatabase.anexperiencedusercanenteransqlquerydirectlyinto naturallanguagequeriesaretranslatedintosqlthatcanbeusedtodirectly Generalhelp ============ fromamedicaldatabase.hermessupportsadhocqueriesthroughnl.these Hermesallowsanoviceorexperienceddatabaseusertoquicklyaccessinformation WelcometotheHermesnaturallanguage(NL)interfacetomedicaldatabase. Selection?1 Hermes. retrieval.thismeansthattherewillbeaslightpausewhiletheclients Hermesusesaclient-serverarchitecturetodotheNLparsinganddatabase 21

22 2)IfyouusedNLthenafterconnectingtotheparserandconvertingthe passednlquerytosql,hermeswilldisplaytheuniquesqlqueriesreturned. ansqlquerybyselectingtheentersqlqueryoption. 1)EnteranewqueryusingNLbyselectingtheNewquerymenuoptionORenter TheusershouldselecttheSQLquerythatcorrespondstotheirsearchORselect connecttotheparserordatabaseserver. aquerythenusenewquerytorefineyournlquery. 4)AfterenteringorselectingtheSQLquerythatmatcheswhatyouwanttodo 3)YoucanselectViewSQLtoseetheSQLquerythatwillberun. ThefollowingstepsoutlinehowtouseHermestoaccessthemedicaldatabase: userunsqltorunthesqlquery. weight_heightandvisit.theerrormessagesthatcanbegeneratedarecoveredin partsofhermes.themenuoptionsavailableonhermes'mainmenuarecoveredin tablesthatcanbeaccessed:doctors,demographics,allergies,insurances, Errormessagehelp.ThefinaloptiononthehelpmenuwillprintoutanAbout Databaseschemahelp.Databaseschemahelphasseparatehelpfilesforthesix messageforhermes. thehelpfiles:enternewqueryhelp,entersqlhelp,viewsqlhelpandrunsql help.anoverviewofthemedicaldatabasethathermesconnectstoiscoveredin Therestofthishelpmenuisdividedintoseparatehelpfilescoveringdifferent 4ViewSQLhelp 3EnterSQLhelp 7Errormessagehelp 5RunSQLhelp 6Databaseschemahelp 1Generalhelp 2Enternewqueryhelp Hermeshelpmenu 8Aboutmessage =============== 9Exithelp Selection?9 Hermesmainmenu zeus[2]%exit 3ViewSQL 2EnterSQL 4RunSQL 5Help 6Exit Selection?6 1Enternewquery =============== 22

23 AppendixB-Sampleparses GivemethephonenumberforDr.Aebig. Givemethenamesofallfemaledoctors. Theexistingsystemhandles(butisnotlimited)tothefollowingsampleparses. Givemethenamesofallsurgeons. Givemethe<first,last>nameofallpediatricians. Givemeallpediatricians. Givemeinformationforallpediatricians. Givemethephonenumberfortheheadofradiology. ThenumberoffemalesurgeonsinRegina. Nameandaddressesofallfemalesurgeons. Homephone<of,for>headofradiology. GivemeDr.Aebig'sage. Dr.Aebig'stitle. Headofradiology'sphonenumber. listthenameofallfamilyphysicians birthdateofallmalepediatricians addressandphonenumbersofallfemalesurgeons nameandaddressforheadofradiology draebigsspecialty firstnameandphonenumberfortheheadofradiology ageandaddressfortheheadofradiology phonenumberandaddressofalldoctors phonenumberandaddressoftheheadofradiology <gender,sex>ofdraebig specialtyofdraebig Givemethedoctor'saverageage. totalnumberofdoctors phonenumberandaddressesforfemalesurgeons Averageageoffemalesurgeons. averageageofallpatients<seen>%%notedifferentsemanticmeaning averageageofallpatientsseenbydraebig patientsseenbydraebig patientsexaminedbydraebig averageageofpracticingsurgeons averageageofpatients countthenumberoffemalegynecologists 23