| | | This caseframe allows Plume to recogn,ze file descriptions |
| prepositional phrase, it also splits off an alternative parse in | like: 6 |
| which that attachment is not made. | When all input has |
| | | fop |
| I~een parsed. Plume retains only t~ose parses t~at succeed | fop.Par |
| at the global level, i.e.. consume all of the input. | Others | The file created Oy John |
| following the marker | Plume also tnes to parse pomtionally | The fortran file in ix/ created Oy Joan |
| are discarded. | | |
| fop Oar out ot [x/ ,nro [y~ From [x] to [yJ cooy fop oar too oar coDy /rom [x/ ro [y/ The caseframe notation and parsing algorithm used here are very similar to those described above for clause level input. The significant differences are additions related to the :adiective and :assignedp attributes of some of the cases above. While Plume normally only looks for fillers after the header in nominal caseframes an adiective attnbute of a slot tells Plume that the SlOt filletmay appear before the header. An :assignedp attribute allows cases to be filled through recognition of a header+ This is generally useful for proper names, such as fop and foo.bar. In the example above. the second alternatwe header contmns two '.,ar~ables name and 'extension. that can each match any s=ngJe .vorcI. The ClUeSt=on mark Indicates opt=onal~ty, so that me header can be either a single word or a word followed Dv a per=pal and another word. The first wOrd ,s asmgned to the ~'anaOle 'name. and IRe second (if =t =s mere~ to the vanaOle !extension If 'name or 'extension are matched ,,vnde recognizing a file header, their values are placed ,n the name and extenmon cases of \"hie\" w,ln the above mod,ficat,ons P~ume can parse nomqna, caseframes umng the same algor~ttnm that ~t uses for clausal caseframes that account for complete sentences. However there are some interactions between the two levels of parsing. In particular, mere can be ambiguity about where to attach marked cases\u2022 For anstance. In: Copy me fortran file ,n [,:/ to [y/ \"~n [xr\" could e,her fill the directory case of the hie described as 'the fortran hie or could fill the dest+natBon case of the whole copy command. The second interpretation does not work at the global level because the only place to put \"to [y}\" ,s tn that same destination case However. at the time the file descrlpt,on ts parsed, tins information is not avadable and so both possible attachments must be considered In general, if Plume is able to fill a case of a nora,hal caseframe from a \".If an interface could recogmze any of these examptes +t specified cases, like direct ObleCt. in the usual position in the sentence -immediately following the header for direct object. Any input not accounted for at the end of this procedure is matched against any unfilled cases, so that cases that are supposed to be marked can be recognized without their markers and pos=tionally indicated cases can be recognized out of their usual positions, This flemble. interpretive style of matching caseframes against the input allows Plume to deal with the kind of variation in word order illustrated in the examples above. The above examples implied there was some method to recognize files and directones They showed only atomic file and directory descriptions, but Plume can also deal with more complex ObleCt descnptions In fact, in Plume grammars, obiects as well as actions can be described by caseframes. For instance, here =s the caseframe s used to define a file for NLVMS [*f~le* :.c f-type nominal :header file ' :name ?(%period ~extension) : cases ( name : assignedp t name) ( extension : assignedp t extension :marker written in :adjective <language> :filler <language>) (creator :filler *person* :marker created by) (directory :filler *directory* :marker in) ] 4 n rme syntax used ,.',,.n VMS. chrectorles are ,ncl.calecl Dy sauare Dtackefs. 5~qa~,~ ~,mOl,hed er~; asSoclaled \u2022 .,fn ~totnmal , a~|f'~tf~e5 The current implementation of Plume is based on the nominal and clausal level caseframe instant=ation algorithms descnPed above. Us=ng these algor=thms and a restr=cted clommn grammar of caseframes like the ones ShOWn above. Plume can parse a w~de variety of ~mDerat~ve and declarative sentences relevant to that doma=n. However. ?rhR Curren! ,rnoleftl~nt;~llon ,)1 PIIIIII@ might seem unreasonable to a uSer that ~t could not recognize all of the others Moreover g~ven any of the above examples, a user might reasonaPly expect recogmt=on of related sentence level inputs hke Create the hie on Monday' J~m created the hie on Monday Dt~ J~m create the hie on Moneay ? Was the hie create(l Ioy J~m on Monclay ~ Who created the hie on Monday ? What day was the hie created on? The current ,mplememation of Plume has no means of guaranteeing such regularity of coverage. Of course, this problem of patcl~y syntactic coverage is not new for restricted doma=n parsers. The lack Of syntactic generality of the original semantic grammar {3] for the Sophie system {21 led tO the concept of cascaded ATNs {10} and the RUS parser {1 I, A progress=on w=tln s=milar goals occurred from the LIFER system [91 to TEAM {6] and KLAUS [7]. The bas=c oDstacle to ach~evmg Syntactic generality ~n these network-based approaches was me way syntactic and semantic information was m=xed together +n the grammar networks. The sOlutions, therefore, rested on separating the syntact=c and semanttc reformat=on. Plume already incorporates just me separation of syntax and semantics necessary for syntactic generahly general syntactic knowledge resides in the parser whde semantic =nformat=on resides ~n the grammar This suggests that syntactic generahty ~n a System like Plume can be acnreved Qv ,morowng the parser s caseframe ,nstanttatJon algOrithms .vHnou{ 3n~,. malor changes to arammar Content ,n terms of me above examples =nvo~wng ;reafe =t suggests ..\"Je can use a s4ngle \"create\" ,,:3seframe to nandte .~11 the examples We Simply need to prowde suHable extensions to the existing caseframe nslantlatton algoNthms In the next section we present a detaded deszgn for such extensaons operates for the following \"create\" caseframe in the context of NLVMS [ *create* : cf-type clausal :header <create> : cases (creator :filler *person* :positional Subject) (createe :filler *file* :positional Direct-Object) (creat ion-date :filler *date* :marker on) Create ~oo Oar on Moniaav 2m crealecI tot)oar on Mor~Uay 2. I Passives Plume recogn,zes pasture sentences lhrough ~tS processing Once me main verb has been located a sl0ecsal verb cluster processing mechanvsm reads me verb cluster and determines from il whether me sentence ts acttve or passive 'j The parser records tills =nformaticn in a special case called 2. We will present our general design by showing how it \"%voice\". |
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"text": "The prtmary diffiCulty for Plume .,.,~ln mterrogatwes ~s that 3S these examoles ShOw me number of variations in stanclard COnStituent order is much greater than for tmperatives and dectaratJves.Interrogatives come in a w~de variety of forms.depending on whether the question is yes/no or wh: on which auxiliary verb ~s used: on whether the voice is active or passive: and for wh questions, on which case is queried.On the other hand. apart from var)ations in the order ancl The parse template associated with the above top-level pattern for yes/no questions is:",
"content": " | | | | a The second more detailed parsing phase is organized ~t never looks any further left ,n the ~nout than could match an ObleCt query or a marked case query, |
| Similar caseframe relative for caseframe for the creation-date cases are generated the creator case. and case. aux kernel-casetrame + (:query) | in differing the in the | \"person\" \"date\" only in | the header of the nom=r'al caseframe ~as already parsed any omer ~ncluding the following: relative to the primary caseframe Associated with each top-or ,f ,t Oos'.-r~ommat cases of the nommal caseframe no further left level pattern, there is a corresponding parse femo/ate. A What did Jsm create ~ than the r~ght hand end ot; them parse template specifies which parts of the primary By whom was fop created? sz |
| :relative-case-name Relative cases are used s~mdarly to the ordinary marked cases of nominal caseframes. In essence, ff the parser ~s This template tells the parser that the input consists of the placement of marked cases, there is only one standard constituent order for =mperatives and only two auxiliary verb matched in the first pass followed by a for :kernel-caseframe. For example. ~n: declaratives (corresponding to active and passive voice). We parsmg a non,nat caseframe ~nd finds the marker of one have exl~lO=tecl th=s low variability by building knowledge of O;d J~m create fop ~ of ~ts relative cases, then it tries to instanhate the :relative-cf It performs tms instantlatlon ~n the same way as ,f me relatwe.cf were a top-level clausal caseframe and the word the imperative and declarative order into Plumes parsing algorithm. the auxtliary verb. \"did\" appears hrst followed by a kernel-However this is impractical for the larger number of variations associalecl with interrogatives. caseframe. \"Jim create fop\" Note ~ow the kernel-that matched the header were ,is main verb. An ~mportan! Accordingly, we have designed a more data,driven approach caseframe looks exactly like a declarative sentence, and so | Fop oar was creamd by Jim b. it COnsumes. but Otherwise ignores any relatwe pronouns iwno .,vn~;.m ~,.,n~n rr~ar ~ that ~mmediately precede the segment used to instantiate the relatwe-cf Tnlg ~neans rna~ 3/i words, including \"thar\" .~vdl ~e 3ccounrec #or ~n \"t/le file ttlat Jim createc .:.)t~ ~/lonclay\" Who was fop created Oy ? caseframe will' be found in unusual positions and which parls the default parsing process (the one for declarat=ves These ~nputs cannot be satisfactordy discriminated Oy a top-and imperatives) can be used for. level pattern, so the above top-level pattern has twO different parse templates associated with it: FOO oar COuto /'lave dee t~ rFateo ov j,m A simplified example of a top-level pattern for a yes-no FO0 oar ,s Oe,ng (reate~l ~v ~,m Fop Oar was created on MGnclay it does not try to fill the case specified by the relative-case-name ~n the question is: ~ wt~-ob/ect aux kemel-caseframe relative-of: =nstead tms case is filled by (a Oomter to) the Or~g=nal nommal caseframe tnstance: \u00f7 (oOlecr.query~ <aux> (-($verD !! <aux>)~ (&s SverOj Srest wig-marked-case-tiller aux kernel-caseframe 22. Relative clauses The detailed design presented below allows Plume to use d. ff the relal=ve-case.name specifies a marked This top.level pattern w=ll match inputs hke. me followmg: + (roamed-case-query float~ng-case-mar~er} . |
| d=fference ~s that it never tries to fill the case ,,,,nose name can be parsed according to the usual declarative/imperative ~s g=ven by relative-case-name That case =s hlled by the This approach involves two Passes through the inpul: the parsing algorithm | case the \"create\" caseframe to parse nominals hke: rather than a positional one tn the relative.of then ~ts case marker can De consumed, but omerwtse ~gnored. durmg Was fop creafecl Oy J~m ? D~ Jim create fop ~ |
| nommal caseframe which contams the relative case first categorizes the input into one on several primary input For | mstanhataon of me relatwe.cf | This 3110w3 US |
| mstance, suppose the parser =s tryCng to process. 7\"he file J~m createcl on MonclaV And suppose that ~t has already located \"file ' and used that to determine ,t ,s ~nstanhat,ng a \"file\" nominal caseframe It ~s able to match {aga,nst 'created\"~ me \u2022 marker of the relative caseframe of \"hie' shown above. It In addition to spec:ficatJon of where to find components of categories incluOing yes-no questions, several kinds of wh-cluestions, statements, or ~mperat=ves. the primary caseframe a parse lemplate ~ncludes The second Pass annotations (indicated by a plus sign) in the above performs a detaded parse of me input based on the template for yes/no questions, there =S lust one annotatton -ctassfficat=on made in the first Pass. The rules used contam ~uery. Some annotations, hke thiS one ,ndlcate what type bas=c syntactic ~nformat=on al3out Enghsn. and will rema,n of input has been found, while others direct the processing constant for any of Plumes restricted domam grammars of of the parse template. Annotations o! the first type record semantic caseframes for Enghsh which case is being queried ~n wn questfons, mat ~s. which | tO deal wlln \"on hie on\" or \"the care un whlcn jim created the ~n me .gate Jim created ~he file ' 3 Passwe relalave clauses (e g. \"Ihe file that was created on Monday\"t can generally be handled using the same mechanisms used Ior passwes at the main clause level However tn relative clauses, passives may sometimes be recIucec/ by om~thng the usual auxihary verb to be (and the relat=ve pronoun) as ~n: The first element of the above top-level pattern ~s an auxiliary verlo, represented Dy me non-termmal <aux> Th~s auxdiary ~s remembered and used by the veto cluster processor (as though ~t were the first auxd~ary ~n the cluster) to determine tense and voice. AcCOrChng tO the next part of the pattern, some word that ts not a verb or an aux~hary must appear after the fronted auxdiary and before the mare |
| then ~ries to ~nstanhate me relatwe.cf case ,s associated w,m the wh word. | \"create\" Wh questions thus using ~tS | the file create(l on Monday verb ( is the negation operator, and !! marks a |
| standard tecnmdues createe the case of \"create\" specff=eo as the relallve-case-except real ~! does not try to fill name Th~s mstanr~at~on succeeds wllh \"Jim' gong =nip include one of the following annotatTons SuOlect-query. The first level of process=rig +nvolves an ordered set of Prelect-query. and mar~ea-case-que~ Marked case queries r~D-/evel patterns. Each too.level pattern corresponds tO one correspond to examples like: | dislunction). To account for such reduced relative clauses, the Next. the scanmng operator &,~ tetls the verb cluster processor will produce approonate hatcher to scan until it finds $vero which matches the additional readings of the verio clusters ,n relahve clauses for which the relative pronoun JS m~ssmg header of any clausal caseframe F~nally. Srest matches |
| creator and \"on Monday\" bemg used to hll creatmn-date of the primary =nput categor=es ment~onecl adore Th=s The parser then uses (a pomter to) the nommat caseframe classificatory matchmg c~oes not attempt to match every On what day d~d J~m create too \u00b0 | the remaimng ~nDut. This may lead to multlOle oarses, mcludmg one for like this: the above example s~mdar to the correct one for: |
| currently +,vord +n the input sentence but only to do the ram=mum being instant~ated. \"file\" to fill createe, the What day d~d Jim create /oo on ~ | [*file* the file Jot~n crea[e~ on Monclay If the top-level pattern successfully matches. Plume uses |
| :relative-case-name case of \"create\" necessary to make the classdicat=on. in which a case marked by a preposition iS 13eing asked and the newly created Most of the relevant | the assoc~atecl Parse template to clirect ~ts more detaded |
| instance of \"create\" is attached to this mstance of \"file\" as a modifier ,nformat~on is found at the beg=nnmg of the ~nDuts. In aPout. AS illustrated here me case-marker in such queries ioart=cular, the top-level patterns make use of the fronted can either precede the wn word or appear somewhere .after | (:relative-cf *create* :relative-case-name createe These amb=guaties wdl De taken care of by Plume s processmg of the ~npul. The goal of this second pass standard ambiguity reduction methods through the input ~s to mstantiate the caseframe |
| aux=liary verb and wh-worcls tn questions. the verO. To deal w;m this, me parse template for marked More comotetely. Plumes atgor~mm for relattve clauses ~s: case quenes has the annotation tloa~na-case-marker. This | :marker <create> corresponding to the heacler matched by Sverlo in the top-] 2 ] interrogatives level pattern, The concept of a kernel-casetrame is |
| AS well as classffymg the input, th~s top-level match ,s annotation ~s of the second type thai ,s =t affects the way 1. When processing a nommal caseframe. Plume scans for the ;markers of lhe rela{tve cases of the nominal also useci to determme the iclenttty of the caseframe To be Plume processes the associated parse template. | in addmon to handling passaves 3no -e\u00a2ahve :lauses. important to this stage of processmg. A kemel-caseframe ,re also wish {he =nformatlon ~n me \"c'eate -\"aseframe to Corresponcls to that part of an ~nput that can be processect |
| caseframe at the same t~me as [t scans for the =nstant=ated. Th=s =S =moortant to dO at this stage because | hanclle ~nterrogatlves tnvolvlng \"create' according to the algorithm already budt into Plume for ~cn 3s |
| regular case markers ol: that nominal caseframe the deta,led recognmon Ln the seconcl phase ts neav=ly Some top-level patterns result ~n two poss=bdmlles for parse | ~1C Jim create me hl~. {~n MG;I,I]V ' declarative and imperative Sentences, | |
| 2. If it finds a marker of a relatwe case. ~t rues to de~enclent on the ~clent=ty of his top-level casetrame The templates, For example, the follow=no top-level pattern | W,aS r/le /lie cre3teo OV J~m or} '.4L,\",I.]/~ |
| inst~ilntlate the relaltve.cf lust as though if were the special symbol. SverO. that appears exactly once =n all top-Top-level clausal case|tame and the header were ~ts mmn '/erb. ~.xcept mat: level patterns, matches a heacler of any clausal caseframe < ,'/n.'NorO > < at.ix > i ( Sv~rto ii .--at.ix > ~ $vf~rt~ $',f=.~t | 911 also ,Jllfltrrtallve or neqallVe clelerrrllnes ,/I/ho c.reare(~ the hie On ~f,unc,av ' I~le lense ol me What clay was the hie crejleC ,: | sentence | and | whelne\u00a2 | ,l s |
| We call trte caseframe whose heacler is matcnecl by SverO | | |
| the primary casetrame for that input. | | | | IOSn ,\u00a2lGitec! .~DleCt is dlloweO lo iJasslv,ze ,I u~ere ,s a case .~,ln a !IW~ \" MaIV ,VaS ~iVell a boow \" ,iOln I OoSlhO.al Ne .:air thus uoderslano mq.ecboiolecI \",~ive ' .Ise!~,3me P Ihl fhl~ ~allern. .'~nly ii1OuIS wrlefe tl~e tronfecl auxlllarv .\u00a2+ ,'he first $1ol -;e~le,~<'es me worO ,~ rh~ sentence are alloweo t'he rrl()re \",'+=nplex ~anerr; ~al ,s ,-,\u00a211 13oln a achJally .lsecI P)v PfLIIn~ dllc)ws ofeuu~lfiol)dll.~/ i~l,|fke 0 \"ases ',~ ionear f]if~,-' i~lihaliv as ,,felt |
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