This thesis is concerned with user interface aspects of expert systems, and in particular tools for the design and management of such user interfaces. In User Interface Management Systems (UIMSs) in general, the user interface is seen as a separate structure. We investigate the possibilities of treating an expert system user interface as separate from the reasoning process of the system, and the consequences thereof.

We propose that an expert system user interface can be seen as a combination of two different structures; the surface dialogue, comprising mainly lexical and syntactical aspects, and the session discourse which represents the interaction between user and system on a discourse level. For the management of these two structures, a tool consisting of two modules is outlined. The two modules are the surface dialogue manager and the session discourse manager. Proposed architectures for these two modules are presented and discussed. The thesis also outlines further steps towards a validation of the proposed approach.