Análisis sintáctico conducido por un diccionario de patrones de ...

ABSTRACT
Syntactic analysis of Spanish language has been following the same research
path of syntactic analysis of English language. What this work intends is obtaining an
adequate model for syntactic structure acquisition and structure disambiguation for
Spanish language analyzing some of their diverse characteristics.
In this thesis we review several formalisms chosen from the two main
perspectives developed for syntactic analysis of natural languages: constituent
grammars and dependency grammars. We analyze their subcategorization description
and its relation to semantic roles or actants. We investigate the appropriate description
of syntactic structures for Spanish language, a language with relaxed word order
constrains, wide prepositional phrase use, direct object differentiated by prepositional
phrase realization, and duplication of syntactic valences among other characteristics.
We argue for the specific description of each predicative word: verbs, adjectives and
nouns, as defined in dependency grammars .
Nowadays it is not possible to reproduce the way human beings disambiguate
word links in a phrase. We share the idea that human beings employ different
knowledge. Our syntactic structure acquisition model considers three types of
knowledge: lexical, semantic and phrase structure. For syntactic ambiguity resolution
we propose the classification of the output of the syntactic structure acquisition
system composed of a module set. Each module is built based on a different method
that represents a specific knowledge. Each module gives a set of weighted variants.
Those weights are based on the satisfied characteristics in each method. So, each
module gives a quantitative measure of the probability of each syntactic structure in a
dependency structure format. To disambiguate syntactic structures a voting module
uses the weights assigned in each module, voting for the maximum added value of
variants. The result is a classified list of the syntactic variants.
The system includes government patterns module, semantic proximity module
and extended CFG module. The three methods require the compilation of dictionaries:
the advanced government patterns dictionary, the semantic network and the extended
Context Free Grammar (CFG) rules. The advanced government patterns refers to
lexical knowledge, the description of the arguments for predicative words, similar to
that in the government pattern dictionary of the Meaning ⇔ Text Theory, associated
to semantic valences. We propose an updated description computer-adequate and
enriched with statistics of syntactic realization, statistics of diverse realization for the
same valence and statistics of valences compatibility.
The CFG rules refers to phrase structure knowledge based on constituents. We
create an extended CFG for Spanish language (with gender and number concordance)
and we implement a chart parser. We assume equally weighted variants for the CFG
module. The semantic network refers to semantic knowledge. When several structures
are quite possible or adjuncts attachment is ambiguous the semantic proximity, i.e.,
the concepts more close related to the words in the possible constituents, could help
to disambiguate structure variants. The idea behind the semantic proximity is finding
the shortest paths between constituents obtained from the CFG module. It employs a
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