The notion that a text is coherent in virtue of the `relations' that hold between its component spans currently forms the basis for an active research programme in discourse linguistics. Coherence relations feature prominently in many theories of discourse structure, and have recently been used with considerable success in text generation systems. However, while the concept of coherence relations is now common currency for discourse theorists, there remains much confusion about them, and no standard set of relations has yet emerged. The aim of this thesis is to contribute towards the development of a standard set of relations. We begin from an explicitly empirical conception of relations: they are taken to model a collection of psychological mechanisms operative during the tasks of reading and writing. This conception is fleshed out with reference to psychological theories of skilled task performance, and to Rosch's notion of the basic level of categorisation. A methodology for investi...

This thesis investigates the impact of the pragmatic situation on surface generation. It presents new surface generation techniques that improve on both aspects of surface generation: (1) lexical choice, which consists of choosing words and their associated syntactic structures and (2) syntactic realization, which consists of combining these partial structures into grammatical sentences. Because surface generation depends directly on aspects of the pragmatic situation, these new techniques allow a purely conceptual input to be expressed by a greater variety of linguistic forms and with more sensitivity to pragmatic factors than was previously possible. Specifically, this research focuses on the impact on lexical choice of one part of the pragmatic situation: the speaker’s argumentative intent, i.e., the goal of the speaker to convince the hearer of a certain conclusion. The argumentative intent can be realized by a variety of evaluative expressions appearing at various ranks in the syntactic structure. This thesis describes the selection of four classes of evaluative expressions: judgment

This paper is an attempt to eliminate Wilkinson's conceptual difficulties. In particular, we will try to answer the simple question what is aggregation?

This paper describes the component in the SUNDIAL spoken dialogue system responsible for semantic interpretation of user input. This component, the `belief module ', constructs interpretations using several sources of knowledge, including static knowledge definitions and a dynamic model of dialogue context, and addresses the problem of the hypothetical nature of the recognition and parsing results as well as the general problems of underspecification and ambiguity. 1 INTRODUCTION We begin by elucidating our notion of dialogue semantics so as to motivate the need for a distinct semantic interpretation component in a spoken dialogue system. We then give an overview of the SUNDIAL system, focusing on interactions between components relevant to the interpretation process. The interpretation process itself is described and illustrated. Finally, we suggest that this interpretation process can be seen as an abductive process. 2 DIALOGUE SEMANTICS Semantic interpretation in spoken dialogue s...

This paper compares the use of Lisp and Prolog for the implementation of a functional grammar unification system. To achieve this comparison, we have taken as a starting point Michael Elhadad's FUF system, which is written in Lisp and produced a much smaller and more e#cient Prolog version (PFUF) retaining many of FUF's essential features. Our approach is based on a precompilation scheme that reduces most of the runtime overhead.

Using Argumentation to Control Lexical Choice: A Functional Unification Implementation Michael Elhadad This thesis investigates the impact of the pragmatic situation on surface generation. It presents new surface generation techniques that improve on both aspects of surface generation: (1) lexical choice, which consists of choosing words and their associated syntactic structures and (2) syntactic realization, which consists of combining these partial structures into grammatical sentences. Because surface generation depends directly on aspects of the pragmatic situation, these new techniques allow a purely conceptual input to be expressed by a greater variety of linguistic forms and with more sensitivity to pragmatic factors than was previously possible. Specifically, this research focuses on the impact on lexical choice of one part of the pragmatic situation: the speaker's argumentative intent, i.e., the goal of the speaker to convince the hearer of a certain conclusion. The argum...