No description available.

Verb classifications have attracted a great deal of interest in both linguistics and natural language processing (NLP). They have proved useful for important tasks and applications, including e.g. computational lexicography, parsing, word sense disambiguation, semantic role labelling, information extraction, question-answering, and machine translation (Swier and Stevenson, 2004; Dang, 2004; Shi and Mihalcea, 2005; Kipper et al., 2008; Zapirain et al., 2008; Rios et al., 2011). Particularly useful are classes which capture generalizations about a range of linguistic properties (e.g. lexical, (morpho-)syntactic, semantic), such as those proposed by Beth Levin (1993). However, full exploitation of such classes in real-world tasks has been limited because no comprehensive or domain-specific lexical classification is available. This thesis investigates how Levin-style lexical semantic classes could be learned automatically from corpus data. Automatic acquisition is cost-effective when it involves either no or minimal supervision and it can be applied to any domain of interest where adequate corpus data is available. We improve on earlier work on automatic verb clustering. We introduce new features and new clustering methods to improve the accuracy and coverage. We evaluate our methods and features on well-established cross-domain datasets in English, on a specific domain of English (the biomedical) and on another language (French), reporting promising results. Finally, our task-based evaluation demonstrates that the automatically acquired lexical classes enable new approaches to some NLP tasks (e.g. metaphor identification) and help to improve the accuracy of existing ones (e.g. argumentative zoning).

No description available.

Text in Afrikaans / Twee sentrale probleme word hier ondersoek, naamlik die daarstelling van 'n teoreties adekwate model om leksikale valensie te verreken en die problematiek rondom die beskrywing van Afrikaanse bewegingswerkwoorde. Die vertrekpunt is dat 'n teorie van UG lesikale valensie slegs ten dele verreken. So 'n teorie is gemoeid met die vorm van 'n konstruksie wat op LF-vlak leesbaar is. Gevolglik beskryf 'n teorie van UG valensie net in universele sintakties-kategoriale terme. In hierdie studie word die semantiese en pragmatiese komponente van 'n valensieteorie derhalwe uitgebou sodat daar 'n duideliker begrip verkry kan word van die wisselwerking tussen alle veranderlikes van valensie op 'n taalspesifieke LF-vlak. 'n Valensieteorie word op eklektiese wyse saamgestel uit verskeie ander teoriee. Die apparaat om die sintaktiese komponent van 'n valensieteorie te beskryf, word aan TGGmodelle ontleen. Die semantiese komponent van die teorie word aangevul vanuit die Konseptuele Semantiek en die pragmatiese komponent daarvan vanui t kogni ti ewe grammatikamodelle. Die interaksie tussen hierdie komponente word verreken deur teoriee van leksikalisasie, korrespondensiereels en die passing tussen konstruksies en leksikale items. Die ontleding van Afrikaanse bewegingswerkwoorde spesif iseer die omvattender anali tiese apparaat wat nodig is vir die verrekening van valensie verby die punt waarvoor 'n teorie van UG voorsiening maak. Dit blyk uit hierdie analise dat die valensie van die kategorie in 'n aantal valensieraambeskrywings vir die aparte subklasse saamgevat kan word. 'n Duidelike beeld van die universele en taalspesifiekidiosinkratiese aspekte van hierdie kategorie kan in terme van hierdie valensierame aangetoon word. 'n Verdere hipotese (die onakkusatiwiteithipotese) is dat die sintaktiese verspreiding van werkwoorde ui t hulle semantiek voorspel kan word. Hierdie hipotese word getoets aan die empiriese data van Afrikaanse bewegingswerkwoorde. Hierdie bewegingswerkwoorde word in groepe geklassifiseer na gelang van ooreenstemmende semanties-pragmatiese kenmerke. Daar word getoon dat bewegingswerkwoorde met dieself de semantiespragmatiese kenmerke dieselfde valensierame het. Valensierame is daarom op sistematiese wyse uit semanties-pragmatiese kenmerke afleibaar. Sekere fasette van valensierame word egter ook bepaal deur konvensies soos profilering, en deur bereelde interaksie met 'n basiese konstruksie se argumentstruktuur. / This thesis focuses on the development of a theoretically adequate model to account for lexical valence and to provide the detail for such a model by means of an analysis of Afrikaans verbs of motion. The thesis is a response to a theory of UG which inadequately accounts for lexical valence. A theory of UG is concerned with the universal syntactic form of a construction that is legible on LF level. It therefore describes valence in universal syntactic-categorial terms only. This thesis develops the semantic and pragmatic components of a theory of valence in order that a clearer understanding may be gained of the interaction between all the variables of valence on a language specific LF level. A theory of valence is construed eclectically from several other theories. TGG models provide the methods used to describe the syntactic component of a theory of valence. Conceptual Semantics contributes to the development of the semantic component, and models of cognitive grammar to the pragmatic component. The interaction between these components is explained by theories of lexicalisation, rules of correspondence and the fusion of constructions and lexical items. The analysis of Afrikaans verbs of motion provides the comprehensive set of analytical devices required to account for valence beyond the point of LF. From this analysis it emerges that the valence of this category can be summarized in a finite number of frames of valence for distinct classes within the category. 'n Clear understanding of the universal and language specific aspects of this category is achieved by means of these frames of valence. A further hypothesis (the unaccusativity hypothesis) posits that the syntactic distribution of verbs can be predicted from their semantics. This hypothesis is tested by means of empirical data of Afrikaans verbs of motion. These verbs are classified according to similar semantic-pragmatic features. It is shown that verbs of motion with the same semanticpragmatic features share frames of valence. These frames thus are deducible systematically from semantic-pragmatic features. Certain aspects of frames of valence, however, are determined by conventions such as profiling and the regulated interaction between verbs and constructions. / Afrikaans / D.Litt. et Phil. (Afrikaans)

Text in Afrikaans / Twee sentrale probleme word hier ondersoek, naamlik die daarstelling van 'n teoreties adekwate model om leksikale valensie te verreken en die problematiek rondom die beskrywing van Afrikaanse bewegingswerkwoorde. Die vertrekpunt is dat 'n teorie van UG lesikale valensie slegs ten dele verreken. So 'n teorie is gemoeid met die vorm van 'n konstruksie wat op LF-vlak leesbaar is. Gevolglik beskryf 'n teorie van UG valensie net in universele sintakties-kategoriale terme. In hierdie studie word die semantiese en pragmatiese komponente van 'n valensieteorie derhalwe uitgebou sodat daar 'n duideliker begrip verkry kan word van die wisselwerking tussen alle veranderlikes van valensie op 'n taalspesifieke LF-vlak. 'n Valensieteorie word op eklektiese wyse saamgestel uit verskeie ander teoriee. Die apparaat om die sintaktiese komponent van 'n valensieteorie te beskryf, word aan TGGmodelle ontleen. Die semantiese komponent van die teorie word aangevul vanuit die Konseptuele Semantiek en die pragmatiese komponent daarvan vanui t kogni ti ewe grammatikamodelle. Die interaksie tussen hierdie komponente word verreken deur teoriee van leksikalisasie, korrespondensiereels en die passing tussen konstruksies en leksikale items. Die ontleding van Afrikaanse bewegingswerkwoorde spesif iseer die omvattender anali tiese apparaat wat nodig is vir die verrekening van valensie verby die punt waarvoor 'n teorie van UG voorsiening maak. Dit blyk uit hierdie analise dat die valensie van die kategorie in 'n aantal valensieraambeskrywings vir die aparte subklasse saamgevat kan word. 'n Duidelike beeld van die universele en taalspesifiekidiosinkratiese aspekte van hierdie kategorie kan in terme van hierdie valensierame aangetoon word. 'n Verdere hipotese (die onakkusatiwiteithipotese) is dat die sintaktiese verspreiding van werkwoorde ui t hulle semantiek voorspel kan word. Hierdie hipotese word getoets aan die empiriese data van Afrikaanse bewegingswerkwoorde. Hierdie bewegingswerkwoorde word in groepe geklassifiseer na gelang van ooreenstemmende semanties-pragmatiese kenmerke. Daar word getoon dat bewegingswerkwoorde met dieself de semantiespragmatiese kenmerke dieselfde valensierame het. Valensierame is daarom op sistematiese wyse uit semanties-pragmatiese kenmerke afleibaar. Sekere fasette van valensierame word egter ook bepaal deur konvensies soos profilering, en deur bereelde interaksie met 'n basiese konstruksie se argumentstruktuur. / This thesis focuses on the development of a theoretically adequate model to account for lexical valence and to provide the detail for such a model by means of an analysis of Afrikaans verbs of motion. The thesis is a response to a theory of UG which inadequately accounts for lexical valence. A theory of UG is concerned with the universal syntactic form of a construction that is legible on LF level. It therefore describes valence in universal syntactic-categorial terms only. This thesis develops the semantic and pragmatic components of a theory of valence in order that a clearer understanding may be gained of the interaction between all the variables of valence on a language specific LF level. A theory of valence is construed eclectically from several other theories. TGG models provide the methods used to describe the syntactic component of a theory of valence. Conceptual Semantics contributes to the development of the semantic component, and models of cognitive grammar to the pragmatic component. The interaction between these components is explained by theories of lexicalisation, rules of correspondence and the fusion of constructions and lexical items. The analysis of Afrikaans verbs of motion provides the comprehensive set of analytical devices required to account for valence beyond the point of LF. From this analysis it emerges that the valence of this category can be summarized in a finite number of frames of valence for distinct classes within the category. 'n Clear understanding of the universal and language specific aspects of this category is achieved by means of these frames of valence. A further hypothesis (the unaccusativity hypothesis) posits that the syntactic distribution of verbs can be predicted from their semantics. This hypothesis is tested by means of empirical data of Afrikaans verbs of motion. These verbs are classified according to similar semantic-pragmatic features. It is shown that verbs of motion with the same semanticpragmatic features share frames of valence. These frames thus are deducible systematically from semantic-pragmatic features. Certain aspects of frames of valence, however, are determined by conventions such as profiling and the regulated interaction between verbs and constructions. / Afrikaans / D.Litt. et Phil. (Afrikaans)