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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A System for Building Corpus Annotated With Semantic Roles

Rahimi Rastgar, Sanaz, Razavi, Niloufar January 2013 (has links)
Semantic role labelling (SRL) is a natural language processing (NLP) technique that maps sentences to semantic representations. This can be used in different NLP tasks. The goal of this master thesis is to investigate how to support the novel method proposed by He Tan for building corpus annotated with semantic roles. The mentioned goal provides the context for developing a general framework of the work and as a result implementing a supporting system based on the framework. Implementation is followed using Java. Defined features of the system reflect the usage of frame semantics in understanding and explaining the meaning of lexical items. This prototype system has been processed by the biomedical corpus as a dataset for the evaluation. Our supporting environment has the ability to create frames with all related associations through XML, updating frames and related information including definition, elements and example sentences and at last annotating the example sentences of the frame. The output of annotation is a semi structure schema where tokens of a sentence are labelled. We evaluated our system by means of two surveys. The evaluation results showed that our framework and system have fulfilled the expectations of users and has satisfied them in a good scale. Also feedbacks from users have defined new areas of improvement regarding this supporting environment.
2

Natural language understanding in controlled virtual environments

Ye, Patrick January 2009 (has links)
Generating computer animation from natural language instructions is a complex task that encompasses several key aspects of artificial intelligence including natural language understanding, computer graphics and knowledge representation. Traditionally, this task has been approached using rule based systems which were highly successful on their respective domains, but were difficult to generalise to other domains. In this thesis, I describe the key theories and principles behind a domain-independent machine learning framework for constructing natural language based animation systems, and show how this framework can be more flexible and more powerful than the prevalent rule based approach. / I begin this thesis with a thorough introduction to the goals of the research. I then review the most relevant literature to put this research into perspective. After the literature review, I provide brief descriptions to the most relevant technologies in both natural language processing and computer graphics. I then report original research in semantic role labelling and verb sense disambiguation, followed by a detailed description and analysis of the machine learning framework for natural language based animation generation. / The key contributions of this thesis are: a novel method for performing semantic role labelling of prepositional phrases, a novel method for performing verb sense disambiguation, and a novel machine learning framework for grounding linguistic information in virtual worlds and converting verb-semantic information to computer graphics commands to create computer animation.
3

Utilisation de représentations de mots pour l’étiquetage de rôles sémantiques suivant FrameNet

Léchelle, William 01 1900 (has links)
Dans la sémantique des cadres de Fillmore, les mots prennent leur sens par rapport au contexte événementiel ou situationnel dans lequel ils s’inscrivent. FrameNet, une ressource lexicale pour l’anglais, définit environ 1000 cadres conceptuels, couvrant l’essentiel des contextes possibles. Dans un cadre conceptuel, un prédicat appelle des arguments pour remplir les différents rôles sémantiques associés au cadre (par exemple : Victime, Manière, Receveur, Locuteur). Nous cherchons à annoter automatiquement ces rôles sémantiques, étant donné le cadre sémantique et le prédicat. Pour cela, nous entrainons un algorithme d’apprentissage machine sur des arguments dont le rôle est connu, pour généraliser aux arguments dont le rôle est inconnu. On utilisera notamment des propriétés lexicales de proximité sémantique des mots les plus représentatifs des arguments, en particulier en utilisant des représentations vectorielles des mots du lexique. / According to Frame Semantics (Fillmore 1976), word meanings are best understood considering the semantic frame they play a role in, for the frame is what gives them context. FrameNet is a lexical database that defines about 1000 semantic frames, along with the roles to be filled by arguments to the predicate calling the frame in a sentence. Our task is to automatically label argument roles, given their position, the frame, and the predicate (sometimes refered to as semantic role labelling). For this task, I make use of distributed word representations, in order to improve generalisation over the few training exemples available for each frame. A maximum entropy classifier using common features of the arguments is used as a strong baseline to be improved upon.

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