Annotation syntaxico-sémantique des actants en corpus spécialisé

Semantic role annotation is a process that aims to assign labels such as Agent, Patient, Instrument, Location, etc. to actants or circumstants (also called arguments or adjuncts) of predicative lexical units. This process often requires the use of rich lexical resources or corpora in which sentences are annotated manually by linguists. The automatic approaches (statistical or machine learning) are based on corpora. Previous work was performed for the most part in English which has rich resources, such as PropBank, VerbNet and FrameNet. These resources were used to serve the automated annotation systems. This type of annotation in other languages for which no corpora of annotated sentences are available often use FrameNet by projection. Although a resource such as FrameNet is necessary for the automated annotation systems and the manual annotation by linguists of a large number of sentences is a tedious and time consuming work. We have proposed an automated system to help linguists in this task so that they have only to validate annotations proposed. Our work focuses on verbs that are more likely than other predicative units (adjectives and nouns) to be accompanied by actants realized in sentences. These verbs are specialized terms of the computer science and Internet domains (ie. access, configure, browse, download) whose actantial structures have been annotated manually with semantic roles. The actantial structure is based on principles of Explanatory and Combinatory Lexicology, LEC of Mel’čuk and appeal in part (with regard to semantic roles) to the notion of Frame Element as described in the theory of frame semantics (FS) of Fillmore. What these two theories have in common is that they lead to the construction of dictionaries different from those resulting from the traditional theories. These manually annotated verbal units in several contexts constitute the specialized corpus that our work will use. Our system designed to assign automatically semantic roles to actants is based on rules and classifiers trained on more than 2300 contexts. We are limited to a restricted list of roles for certain roles in our corpus have not enough examples manually annotated. In our system, we addressed the roles Patient, Agent and destination that the number of examples is greater than 300. We have created a class that we called Autre which we bring to gether the other roles that the number of annotated examples is less than 100. We subdivided the annotation task in the identification of participant actants and circumstants and the assignment of semantic roles to actants that contribute to the sense of the verbal lexical unit. We parsed, with Syntex, the sentences of the corpus to extract syntactic informations that describe the participants of the verbal lexical unit in the sentence. These informations are used as features in our learning model. We have proposed two techniques for the task of participant detection: the technique based in rules and machine learning. These same techniques are used for the task of classification of these participants into actants and circumstants. We proposed to the task of assigning semantic roles to the actants, a partitioning method (clustering) semi supervised of instances that we have compared to the method of semantic role classification. We used CHAMELEON, an ascending hierarchical algorithm.

Keyphrases: Actant, Classification, Clustering, Frame semantics (FS), Actant, Circumstant, Semantic roles, Syntactic features, Classification, Clustering, Explanatory and Combinatory Lexicology(LEC), Frame semantics, DicoInfo and Framenet