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| − | These guidelines were built to normalize and standardize UNLization strategies and to guide the development of the natural language generation grammars (which would benefit from these standards as a sort of NL-to-UNL transfer grammar). They should not be taken as the UNL Specifications themselves, as long as 1) they are rather experimental and tentative; 2) they differ, in several points, from the current version of the Specifications; 3) they do not follow some of the existing UNLization policies; and 4) they have not been approved yet by the UNL Community.
| + | The specifications here stated are still experimental and tentative, and have been continuously extended and amended in order to be as comprehensive as possible. They follow the general strategies defined in the [http://www.undl.org UNL 2005 Specifications] (version of June 7th, 2005), but introduce several important changes derived from different UNLization experiences. Although formally adopted in the UNDL Foundation tools, projects and certificates, they should not be taken yet as the official specs, as they are still under construction and have not been widely discussed with the UNL Community. |
| | | | |
| − | == PREMISES ==
| + | *[[Introduction to UNL]] |
| − | These guidelines are derived from three main premises:
| + | *[[Universal Words]] |
| − | Information conveyed by natural language utterances can be represented a natural language independent hypergraph structure.
| + | *[[Universal Attributes]] |
| − | Texts can be treated as a set of semantic nodes interlinked by semantic relations and modified by semantic attributes. Nodes can be either simple (UWs) or complex (SCOPES, i.e., subgraphs, such as clauses).
| + | *[[Universal Relations]] |
| − | The UNL representation is an intrepretation rather than a translation of a given text.
| + | *[[UNL sentence|UNL sentence structure]] |
| − | The main goal of the UNLization process is to represent the knowledge structure of the source text, which should be detached from its verbal structure. This means that the UNL representation should not be committed to replicate the lexical and the syntactic choices of the original, but should focus in representing, in a language-independent and non-ambiguous format, one of its possible readings, preferably the most conventional one.
| + | *[[UNL document|UNL document structure]] |
| − | The UNL representation should be as semantically complete as possible.
| + | |
| − | This means that, whenever possible, all the semantic valencies of the original text should be saturated, including anaphora, ellipses, presuppositions and implicatures. Pronouns and pro-forms, for instance, are expected to be replaced by their antecedents, and should not be represented in UNL, except in case of exophoric reference (indefinite pronouns, interrogative pronouns and personal pronouns that are not coindexed to any existing antecedent).
| + | |
| − | | + | |
| − | == UNL EXPRESSION ==
| + | |
| − | For the time being, the network macrostructure has not been addressed, but it seems clear that the relation “nxt”, proposed by the UNL Centre to link sentences and paragraphs, is syntactic rather than semantic, and it is not appropriate for a network claimed to be mostly semantic. Some alternatives have been considered (especially Discourse Representation Theory - DRT, proposed by Hans Kamp; and Rhetorical Structure Theory - RST, proposed by William Mann and Sandra Thompson), but they are still under investigation.
| + | |
| − | | + | |
| − | The document structure is also subject to change, and it is likely to move to a XML schema, which is still under development. For the moment, the syntax defined by the UNLCenter has been kept.
| + | |
| − | | + | |
| − | == THREE-LAYERED REPRESENTATION ==
| + | |
| − | The basic assumption of the UNL approach is that the meaning conveyed by natural language sentences can be formally represented through three different types of semantic units: UWs, attributes and relations. This three-layered representation model is the cornerstone of UNL and its most distinctive feature over other semantic networks, which normally proposes only two levels: edges and vertices. Nevertheless, it poses several problems to the UNLization as the distinction between what is supposed to be represented by each unit is not always clear. In order to avoid superposition and to facilitate the enconversion process, we have tried to clearly identify the scope of each unit using the following procedures:
| + | |
| − | *RELATIONS represent syntactic relations (subject, object, complement, adjunct) with their corresponding semantic value; | + | |
| − | *UWs represent lexemes from open classes:
| + | |
| − | **nouns, including proper nouns, abbreviations and acronyms;
| + | |
| − | **adjectives;
| + | |
| − | **full verbs;
| + | |
| − | **adverbs (adjunts, conjuncts and disjuncts); and
| + | |
| − | **numbers (to be always represented as Arabic numerals)
| + | |
| − | *ATTRIBUTES represent bound morphemes, closed classes and context-dependent information:
| + | |
| − | **grammatical categories (gender, number, tense, aspect, mood, voice, etc)
| + | |
| − | **determiners (articles and demonstratives);
| + | |
| − | **adpositions (prepositions, postpositions and circumpositions);
| + | |
| − | **auxiliary and quasi-auxiliary verbs (auxiliaries, modals, coverbs, preverbs);
| + | |
| − | **interjections;
| + | |
| − | **conjunctions;
| + | |
| − | **adverbs (specifiers);
| + | |
| − | **text structure (.@entry, .@topic, .@qfocus, .@emphasis, .@relative, etc);
| + | |
| − | **speech acts (.@request, .@suggestion, .@offer, etc);
| + | |
| − | **other context-dependent information (such as politeness, metaphor, irony, etc);
| + | |
| − | Pronouns and pro-forms are expected to be replaced by their antecedents and not to be represented in UNL, except in case of exophoric reference (indefinite pronouns, interrogative pronouns and personal pronouns that are not coindexed to any existing antecedent).
| + | |
| − | | + | |
| − | The main changes concerning the present UNL Specifications are the following:
| + | |
| − | | + | |
| − | == RELATIONS ==
| + | |
| − | The set of relations is exactly the same as defined in the UNL 2005 Specifications.
| + | |
| − | | + | |
| − | == ATTRIBUTES ==
| + | |
| − | The set of attributes has been substantially increased to represent information concerning grammatical categories, determiners, adpositions and conjunctions. The main additions are the following:
| + | |
| − | *gender: @male, @female
| + | |
| − | *degree of comparison: @more, @less, @equal, @most, @least
| + | |
| − | *demonstrative: @proximal, @medial, @distal
| + | |
| − | *preposition: @under, @below, @above, @after, @before, etc.
| + | |
| − | *conjunction: @before, @after, etc.
| + | |
| − | *relative (for the main entry of relative clauses): @relative
| + | |
| − | The decision to represent closed classes as attributes instead of UWs has led to a different way of representing several natural language phenomena:
| + | |
| − | ;this X
| + | |
| − | :UNL Centre: mod(X, this)
| + | |
| − | :These guidelines: X.@proximal
| + | |
| − | ;X is under Y
| + | |
| − | :UNL Centre: plc(X, under), obj(under, Y)
| + | |
| − | :These guidelines: plc(X, Y.@under)
| + | |
| − | ;bigger than Y
| + | |
| − | :UNL centre: man(big, more), bas(big, Y)
| + | |
| − | :These guidelines: bas(big.@more, Y)
| + | |
| − | etc.
| + | |
| − | | + | |
| − | Additionally, the following general principles were adopted:
| + | |
| − | *interjections, filled pauses, phatic expressions and short answers should be represented by the null UW (to be represented as "00") together with the attribute indicating the corresponding speech act (.@confirmation, .@surprise, etc).
| + | |
| − | *the attribute .@entry (mandatory in every scope, including the main one) should be placed at the left (source) side of at least one relation;
| + | |
| − | *the difference between mentioning and using a word (which is a quite frequent situation in a metalinguistic text such as Cratylus) should be represented by the attribute .@mention (which is not the same as "quotation");
| + | |
| − | *attributes should be used in alphabetical order (“.@entry.@past” instead of “.@past.@entry”).
| + | |
| − | | + | |
| − | == UNIVERSAL WORDS ==
| + | |
| − | The set of Universal Words, i.e., the UNL Dictionary, has undergone the most radical change, as we have been using the UNLWN30, a set of UWs automatically extracted out of the WordNet30. In this dictionary, UWs correspond to sets of synonyms (synsets) of English, and may have several different headwords. They are represented as 9-digit strings with the following format:
| + | |
| − | <POS><WORDNETID>
| + | |
| − | where <POS> = {1,2,3,4}, being 1 = noun, 2 = verb, 3 = adjective and 4 = adverb; <br />
| + | |
| − | and <WORDNETID> is the synset ID in the WN3.0.
| + | |
| − | | + | |
| − | == SCOPES ==
| + | |
| − | In order to enhance the possibility of knowledge extraction out of the UNL document, we have restricted the use of scopes only to cases involving semantic ambiguity, such as:
| + | |
| − | *electric [light orchestra], with scope, i.e., a "light orchestra" that is electric; or
| + | |
| − | *electric light orchestra, without scope, i.e., an orchestra that is both "light" and "electric".
| + | |
| − | | + | |
| − | == INVITATION ==
| + | |
| − | | + | |
| − | Finally, we ought to stress that the UNLization standards here presented are tentative and provisional, and they are subject to improvements and changes as soon as they were proved not to be the most adequate ones. In order to provide such enhancements, we would invite UNL Society members and other people interested in UNL to criticize them, to propose alternatives and to help us build an NL-to-UNL transfer grammar as comprehensive as possible.
| + | |
| − | | + | |
| − | == BROWSE BY ALPHABETICAL ORDER ==
| + | |
| − | [[abbreviations]] [[acronyms]] [[voice#Active voice|active voice]] [[adjectives]] [[adjuncts]] [[adverbs]] [[apposition]] [[articles]] [[aspect]] [[verbs|auxiliary verbs]] [[capitalization]] [[cardinals]] [[common nouns]] [[comparative adjectives]] [[adverbs|comparative adverbs]] [[comparative]] [[complement]] [[complex words]] [[compound words]] [[conditional]] [[conjunctions]] [[conjuncts]] [[contractions]] [[coordination]] [[verbs#Copula|copula]] [[degree]] [[demonstratives]] [[determiners]] [[digits]] [[disjuncts]] [[equations]] [[fractions]] [[gender]] [[imperative]] [[indicative]] [[intensifiers]] [[interjections]] [[interrogative]] [[verbs|modal verbs]] [[mood]] [[numerals|multiplicative numerals]] [[nominalization]] [[numbers]] [[numbers in names]] [[numbers in titles]] [[numerals]] [[object]] [[numerals|ordinals]] [[voice#Passive voice|passive]] [[person]] [[pronouns#Personal pronouns|personal pronouns]] [[pronouns#Possessive pronouns|possessive pronouns]] [[premodifiers]] [[prepositions]] [[pronouns]] [[proper nouns]] [[punctuation marks]] [[quantifiers]] [[pronouns#Reciprocal Pronouns|reciprocal pronouns]] [[pronouns#Reflexive pronouns|reflexive pronouns]] [[voice#Reflexive voice|reflexive voice]] [[relative clause]] [[pronouns#Relative pronouns|relative pronouns]] [[spelling]] [[subject]] [[subjunctive]] [[subordination]] [[adjectives|superlative adjectives]] [[adverbs|superlative adverbs]] [[superlative]] [[tense]] [[typographical symbols]] [[verb modification]] [[verb modifiers]] [[verbs]] [[vocative]] [[voice]]
| + | |
| − | | + | |
| − | == BROWSE BY SUBJECT ==
| + | |
| − | | + | |
| − | {{#tree:id=unlization|openlevels=0|root=Categories|
| + | |
| − | *grammatical categories
| + | |
| − | **[[aspect]]
| + | |
| − | **[[degree]]
| + | |
| − | **[[gender]]
| + | |
| − | **[[mood]]
| + | |
| − | **[[number]]
| + | |
| − | **[[person]]
| + | |
| − | **[[tense]]
| + | |
| − | **[[voice]]
| + | |
| − | *part of speech
| + | |
| − | **[[abbreviations]]
| + | |
| − | **[[acronyms]]
| + | |
| − | **[[adjectives]]
| + | |
| − | **[[adverbs]]
| + | |
| − | **[[articles]]
| + | |
| − | **[[conjunctions]]
| + | |
| − | **[[contractions]]
| + | |
| − | **[[demonstratives]]
| + | |
| − | **[[determiners]]
| + | |
| − | **[[intensifiers]]
| + | |
| − | **[[interjections]]
| + | |
| − | **[[nouns]]
| + | |
| − | **[[numerals]]
| + | |
| − | **[[prepositions]]
| + | |
| − | **[[postpositions]]
| + | |
| − | **[[pronouns]]
| + | |
| − | **[[quantifiers]]
| + | |
| − | **[[verbs]]
| + | |
| − | *syntax
| + | |
| − | **[[apposition]]
| + | |
| − | **[[cleft sentences]]
| + | |
| − | **[[complement]]
| + | |
| − | **[[coordination]]
| + | |
| − | **[[ellipsis]]
| + | |
| − | **[[object]]
| + | |
| − | **[[subject]]
| + | |
| − | **[[subordination]]
| + | |
| − | **[[vocative]]
| + | |
| − | }}
| + | |
The specifications here stated are still experimental and tentative, and have been continuously extended and amended in order to be as comprehensive as possible. They follow the general strategies defined in the UNL 2005 Specifications (version of June 7th, 2005), but introduce several important changes derived from different UNLization experiences. Although formally adopted in the UNDL Foundation tools, projects and certificates, they should not be taken yet as the official specs, as they are still under construction and have not been widely discussed with the UNL Community.
