{ "paper_id": "A92-1041", "header": { "generated_with": "S2ORC 1.0.0", "date_generated": "2023-01-19T02:03:42.468670Z" }, "title": "Lexicon Design Using a Paradigmatic Approach", "authors": [ { "first": "Cristian", "middle": [], "last": "Dumitrescu", "suffix": "", "affiliation": { "laboratory": "", "institution": "Research Institute for Informatics Alex", "location": { "addrLine": "Averescu Blvd. 8-10", "postCode": "71316", "settlement": "Bucharest 1", "country": "Romania" } }, "email": "" } ], "year": "", "venue": null, "identifiers": {}, "abstract": "The paper describes models for representation and meth6d~ to handle lexicograp.hic_structures supplied .by the MORPHO-2 sfftem. It was built to m_~n.~ge mono \"hfigual lexicons and to incorporate lexical proce~in~ 1 Introduction Most advaneed systems for natural lanL~3ge \" prgcessing use powerfullexicons and mg_rp_ho-lexical proc~ssi~g.~ ehvironments. \u2022 The s!r4. em descn])ed b~low enables monolifigual lexicon handling and incorporat ~ morpho-lexical processes (i.e. word-form anaanaFysis\" and sy~he.sis' _..~sl a_t _at lexicon, leveL At present,., it works as a component otthe/U _RES envaronment fQi building natural language app.lications Ohlis and Cristea,. _19&_5). S~c6 in our appr_oach .the morphological processes .obey a paradigmatic morphology (Ttt~.-19~), word-f6rms analysis and synthesis take into account, ont~ grammatical endings.(wlj.'ch indudes both desinences and sutr@s.) and the lexicons handled by MORPHO-2 system are root-or lemma-oriented. By. lexicon we don't mean only a collection of roots and associated features. At lexicon level we also encounter the control structures needed for morphological prow.ssi~, morpho-lexical acquisition menus, root modification rules, word-forms synthesis rules, etc. The services provided by the system may be ch\u00a2.~ified according to the follox;vhag, g o,o,~: morphological model .design, lexi.cal st6ck building and morpho-lexicfil pro6essing(Dumitrescu, 1991).", "pdf_parse": { "paper_id": "A92-1041", "_pdf_hash": "", "abstract": [ { "text": "The paper describes models for representation and meth6d~ to handle lexicograp.hic_structures supplied .by the MORPHO-2 sfftem. It was built to m_~n.~ge mono \"hfigual lexicons and to incorporate lexical proce~in~ 1 Introduction Most advaneed systems for natural lanL~3ge \" prgcessing use powerfullexicons and mg_rp_ho-lexical proc~ssi~g.~ ehvironments. \u2022 The s!r4. em descn])ed b~low enables monolifigual lexicon handling and incorporat ~ morpho-lexical processes (i.e. word-form anaanaFysis\" and sy~he.sis' _..~sl a_t _at lexicon, leveL At present,., it works as a component otthe/U _RES envaronment fQi building natural language app.lications Ohlis and Cristea,. _19&_5). S~c6 in our appr_oach .the morphological processes .obey a paradigmatic morphology (Ttt~.-19~), word-f6rms analysis and synthesis take into account, ont~ grammatical endings.(wlj.'ch indudes both desinences and sutr@s.) and the lexicons handled by MORPHO-2 system are root-or lemma-oriented. By. lexicon we don't mean only a collection of roots and associated features. At lexicon level we also encounter the control structures needed for morphological prow.ssi~, morpho-lexical acquisition menus, root modification rules, word-forms synthesis rules, etc. The services provided by the system may be ch\u00a2.~ified according to the follox;vhag, g o,o,~: morphological model .design, lexi.cal st6ck building and morpho-lexicfil pro6essing(Dumitrescu, 1991).", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Abstract", "sec_num": null } ], "body_text": [ { "text": "In order to build the mo.rphological model, an inte~ated environment which allows edi'-tmg , viewing and comping the morpholoffical model descrioti6n, is available to the De-fining the morp.ho].ogical model takes place m several steps, during \" .whiCh the lin~afist hfis to specify the following; a) the categories, subcategories, features and their values, in a hierarchical manner b) the paradigmatic descriptions c) the default feature specifications associated to each paradigmatic description d) the lemma -entry correspondence, for each paradigmatic description e) the inflectional paradigms and root detection rules. . The hierarchical de~crip0.'on of features is achieved by correlating several feature sp&ifications.+A feature s pe:#fication is given re, the fo .rna of a,(fe~ture: v~lu 9 ) pair.. We ~ a paradigmatic 9escripdon. a. hierarchical description build of several stmple (teature: value) pairs. F.lgu}e 1 ~ W-~nts, in the forrg_ of an incomplete tree, the hierarchical deki-ipfign Of features trom the morbhologi.cal model.for the Romanifin ~.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Morphological Model Design", "sec_num": "2" }, { "text": "By tree trave.rsal, all paradigmatic dgscriptions of the m.oclel ff~ay b~y generated.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Morphological Model Design", "sec_num": "2" }, { "text": "Each non-terminal node contains a single feature speck'_cation. The leaf nodes .may contain one or more teature (#cations: A._gzordi~g \" .to the su~r selection criteria, whib..h is a~ plmd when xasmng a non-terminal node, we can distingm~a", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Morphological Model Design", "sec_num": "2" }, { "text": "Y'2 COMMON PROPER IND CJ ,,, GER /- .... /. ~[/.~ ~s~ / \". PL 1 2 N/A G/D F'~mre 1 Hierarchical description of features", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Morphological Model Design", "sec_num": "2" }, { "text": "O-lOOSE nodes(when only one successor is selected) or V'OREACH nodes (_when the individual selection of each successor is required). In the figure, a V'OREACH node is outlined by a curve drawn over the emerging edges: By trave~ the tree across the longest path_ which starts trom the root node, thru CHOOSE nodes only, th6 selector of a paradigmatic description is obtained (e.g.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Morphological Model Design", "sec_num": "2" }, { "text": "CAT = NOUN&SCAT = COMMON&GEN = ~ CAT = VERB).", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Morphological Model Design", "sec_num": "2" }, { "text": "The _description attached to a leaf node ts represented by means of a morpho-lexical acqui#. \"tion scenario. A scenario entry (further on referred to as a slot) corresponds to a point of the parad~aatic de4~'ption spa~.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Morphological Model Design", "sec_num": "2" }, { "text": "Selectors of those descriptions allowin K default feature specifications are attached with (feature: value )pairs which are ~uk inheritances of the corre.sponding slots, fn our example me tollowing association is l~asu'ble: (CAT= VB) -> (pER 12 3).", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Morphological Model Design", "sec_num": "2" }, { "text": "The area of the m9rphplogi . c. c. c. c # model where the lemma -entry (from par adigmati.c -de\u00a3~ripdpn ) correspondenees are descrl]ged, .consi~.-in a specification ot the points from the paradigmatic . .de~ipdon spa_ces , which characterize the lemma field from the lexicon entry. Thks way, the lexical level required by the lexical transfer is ensured.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Morphological Model Design", "sec_num": "2" }, { "text": "The .last step in. the morphologi.'cal model description is to inform, me s3~stem about how to buTdd inflexional p~adigms -and root detection rules. For each paradigma_ tic desci-iption the lin-t~st~ may specify more paradiginatic encfing \" families from which t e system then builds the inflectional paradigms. For the Rom/mian hnguage, there have been identified 136 inflectional paradigtns.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Morphological Model Design", "sec_num": "2" }, { "text": "). Bas~l o(n ~'I~e 1.mf198~onal pgradign~ the system will determine the rules for root detection and word-lorm generation.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Morphological Model Design", "sec_num": "2" }, { "text": "Such a rule has the follpwing form: < inflexion >: = (< inflectional-paradigm > < slot-number >) with the followin~ meani~_.: a) if a word ends in < inflexion > then ~dae root is what rernaim from the word after dropping the < inflexion > ~dae root belongs to the < inltectional-Lgaradig m > othe contextual-information corresponding to the current word is ~'en by < slot-number > b) g a root belongs to the < inflectional-paradigm > and it is used in the context given by < slot -numlSer > then othe word is obtained-by concatenating the given root with the < inflexion >. The lexicographer's interface is stric0y deoendent on the Sofpeo-fim~ejCatiomfrom the linguist's interface sifice a'lar~e part of the ormer is built automatically from the spedfications o-f tile latter.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Morphological Model Design", "sec_num": "2" }, { "text": "MORPHO-2 lets the lexi.cog~apher define new entries in the lexicon by means of a user-frien ..dly window oriented interface.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Lexical Stock Building", "sec_num": "3" }, { "text": "Alexicon entry, has the foll6wing formal structure: < entry> :", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Lexical Stock Building", "sec_num": "3" }, { "text": ": = (< lemma > (< par a .digm,atic-description-selector > < inflexional-paradigni > .. < root > < morpho].ogic-description >)", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Lexical Stock Building", "sec_num": "3" }, { "text": ", , , ( < senianfic-description> ) ) ) The fields < lemma >, < _p,gradigmafi'c-deslaJption-selector > and < inflexional-paradigm > have 0ae obvious meaning.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Lexical Stock Building", "sec_num": "3" }, { "text": "The field < root > may contain one or more roots~Inserting r .oots in the lexicon takes place in such a way that these should inherit the morphologicaI descriptions bel6nging to the slots where they occur.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Lexical Stock Building", "sec_num": "3" }, { "text": "By < syntactic-description > ~ refer to restrictions on cooccurrence with other words .(or phrases). In order to slxcify such restrictions for the Roman~ ~6", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Lexical Stock Building", "sec_num": "3" }, { "text": "we have perfor/ned subeategorization of verbs based on their valency, object categories which .they govern(ea,~ a direct object may be an ac-cu~.a. -tive noun without pre0osition, a reflexive pronoun or a nonfinite form of a verb) and semantic features.The latter allow a noncontextual subcatego.rizati.on (for exarn ple of nouns_) and a contexual one ~ sel~tional resfrictions (ih the case of ve.rbs). Typically, verb~ have a valency between 1 and 3 (th. otigh imp&sonaI verbs may have valen .cy 0). The inlransitive verbs.are claksified accor .ding to semantic criteria (verbs of motion~ state) or by their syntactic usa~ (like predicativi~ auxiliaries, urgpers6nal verbs with dative ). W'e should-notice that the same verb maybe transitiv 9 or intransitive, accor \"ding to its m e.,~fin~; for example a ajuq. ~ (to get to) with the meaniffg a pt/nde (to catch) is trangitive and ~tli th~ mefining aft su~ (tobe enofigh) is h/transitive. Trivalent.verbs \"m.iSlude verbs tgking: ~wo direct., objects which have different meanings and are not coordinated (the first one is doubled by an accusative, personal pronotai). l asked him ~ the book. For each syntactic .des~i. \"ption, the lexicographer ma.y provide one or more semantic degcril~ion~ The field contaim the name oT a case-frame structure placed m a generic-specific hierarchy. The actual semantic descriI~tious are stored in a separate data area, than the rest of the leficon, and they are managed independently of MORPHO-2.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Lexical Stock Building", "sec_num": "3" }, { "text": "A lexicon e21itor offers the lekicographer commands for delet-~g. modifying a lexicon entry and ~aen\" listing according t 9 different requests with respect to entry fields (Dtffnilxescu,1991) .", "cite_spans": [ { "start": 172, "end": 191, "text": "(Dtffnilxescu,1991)", "ref_id": null } ], "ref_spans": [], "eq_spans": [], "section": "Pe Ion", "sec_num": null }, { "text": "The target natural l,~mguage processing system is the beneficiary of the morpho-lexical processes execut~ byMORPHO-2. _Wordforms ~ and synf.hesis are mediated b~ a proce.ss interlace.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Morpho-Lexical Processing", "sec_num": "4" }, { "text": "In the case of 1.~c~.. analysis, if the interface is giyen a se-quence_of words, it will return a sequence of morpho-lexical atoms. \"lhe stru~ure of these atoms is presented belo~ ( ( (< para~cMesc0\"pfi'on-sclector > < fiaorph~logic .-~:", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Morpho-Lexical Processing", "sec_num": "4" }, { "text": "xi. \"l~tion> .... (< synt~_~c-t~escriptioh> ) ) ) ) A morphological descriodon contaM~ both contextual and context-free inf6i'mafion. The former is oOained from en \"ding and the latter from the lexicon en_tly corresponding to th~ root. The information for the other fields from the atom stru~ure is ~ taken from the lexicon entw_ correslx)nding, to the root.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Morpho-Lexical Processing", "sec_num": "4" }, { "text": "With respect to the result of morphoqogi _c91 congruence and root relxievfl within the lexico~ we may daTsfifv the moroho-lexical atoms as unambiguous, am _b~ru_ous ~ind undetermined.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Morpho-Lexical Processing", "sec_num": "4" }, { "text": "The unambiguous morlaho-lexical atoms assodate the analyzed word with a single [emma. Inthe case of a root which .corr~po.nds to one lemma and ~ more poss~.qgle morpholegi.cal descriflions, for the same para.digmatic description selector, the system will attempt to compact them.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Morpho-Lexical Processing", "sec_num": "4" }, { "text": "The ambiguous morpfio-lexical atoms come from words to which severaHemmae .may be attached. The association of a root with several lemmae is possible either due to ambiguity ot category (e.g. noun vs. verb) or to apparent homography, gene~at&1193/ the absence of prosodic ma?rkers in the R0hmifi~n Kangt~. (m6dele, mod6le, ac61e, ficele, modfil, m6dtfl, etc.) . The lX~O_~ iriterpretafions are ordered in such way that those Which come from shorter roots (that means longer ending) have prio.rity.", "cite_spans": [ { "start": 298, "end": 314, "text": "Kangt~. (m6dele,", "ref_id": null }, { "start": 315, "end": 322, "text": "mod6le,", "ref_id": null }, { "start": 323, "end": 329, "text": "ac61e,", "ref_id": null }, { "start": 330, "end": 337, "text": "ficele,", "ref_id": null }, { "start": 338, "end": 345, "text": "modfil,", "ref_id": null }, { "start": 346, "end": 353, "text": "m6dtfl,", "ref_id": null }, { "start": 354, "end": 359, "text": "etc.)", "ref_id": null } ], "ref_spans": [], "eq_spans": [], "section": "Morpho-Lexical Processing", "sec_num": "4" }, { "text": "The undetermined morpho-lexical atoms correspond to words which have no entry in the lexicon. The atoms generated in this situation have the foll6wing structure: (UNKNOWN < unknown-word> ( < ixm~'ble-root > < morphologicMe.scri'pdon >'~*) The unknown word is associated with aql legal segmentations and for each of them the morphological inf6i'rnation deduced from the identified en \"dings is prOcidex[ Lexical synthesis is the reverse of lexical analysk The process interface ensures conversion of a morpho-lexical atom sefluence into a word _Sg:luence. The morpho-lekical, synthe.sis requi/es the descri'ption of niorpho-lexical atoms accordifig to the pattern: I. < entry-identifier > < morpholoKjc .Mesc~.p0.'on > ) .whe~ < entry-identifier > maybe a lemma, a root or a semantic descri~on.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Morpho-Lexical Processing", "sec_num": "4" }, { "text": "We have to point out that previous to morpho-lexical analysis and svnthe.~\" tile target pr~r may co n0g~re the structureot morpho-.lexical atoms according to tlie desired application, by means ot a communication protocol.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Morpho-Lexical Processing", "sec_num": "4" }, { "text": "The MORPHO project, started in 1986, has achieved as a first result, a prototype version now available on a PDP-11 compatible computer. The second version of the system, the one presented in this_~aper, is ing.plemented in C on a IBM-PC. compah'ble.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Implementation", "sec_num": "5" }, { "text": "The network re~ntafion of data and techrfiques used for, implementation, lille lexicon in d_e \"_rag using prefixekt virtual B . trees _(b,xsed on which, for 20000 i~seud'o:random generated words, of variable length, retrieval r&l .uires 2 external acxx.sses only), have led to an ave.rage response time of lexical processes, qutte independent of the leficons ~ (for more.details on performance an$1ysis see (Tufts and Dumitrescu, 19~) ).", "cite_spans": [ { "start": 407, "end": 429, "text": "(Tufts and Dumitrescu,", "ref_id": null }, { "start": 430, "end": 434, "text": "19~)", "ref_id": null } ], "ref_spans": [], "eq_spans": [], "section": "Implementation", "sec_num": "5" } ], "back_matter": [], "bib_entries": { "BIBREF1": { "ref_id": "b1", "title": "A human enginge \"nng approach to natural language question amwe_rh3g -. 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