Introduction

Lexico-semantic knowledge is becoming increasingly important within the area of natural language processing, especially for applications such as word sense disambiguation (WSD), information extraction (IE), and question answering (QA). Although the coverage of handmade resources, such as WordNet (Fellbaum, 1998) (introduced in Chapters 1, 2 and 3), in general is impressive, coverage problems still exist for those applications involving specific domains or languages other than English.

We are interested in using lexico-semantic knowledge in an open-domain question-answering system for Dutch. Obtaining such knowledge from existing resources is possible, but only to a certain extent. The most important resource for our research is the Dutch portion of EuroWordNet (Vossen, 1998); however its size is only half that of the English WordNet. Therefore, many of the lexical items used in the QA task of the Cross Language Evaluation Forum (CLEF) for Dutch cannot be found in EuroWordNet. In addition, information regarding the classes to which named entities belong, e.g. Narvikis-a HARBOUR, has been shown to be useful for QA, but such information is typically absent from hand-built resources. For these reasons, we are interested in investigating methods which acquire lexico-semantic knowledge automatically from text corpora. See also Chapters 5 and 14 for more support of such an approach.

The chapter is organized as follows: in the next section, we briefly describe the question types for which lexico-semantic knowledge will be used, and in Section 16.3 we describe related work.