Formal Design, Veriication and Simulation of Multi-modal Dialogues

We have designed and implemented a dialogue management design tool for use in dialogue design as a component of user-interface design in multi-modal applications. The tool provides: a formal language (typed feature structures) for describing states and events; a simple rule formalism for specifying dialogues; an automatic dialogue-property checking module; a dialogue-simulator for interactive testing of designs. It is designed to be compatible with GUIDE (Mellor et al., 1995) { a hardware/software environment permitting arbitrary coupling of input/output devices to facilitate experimentation in multi-modal design { but this does not restrict its generality. Dialogue is a notion that researchers in Human Computer Interaction are naturally interested in because they are keen to be able to design dialogues with certain properties in mind, notably usability (howsoever conceived). At least some such properties can, it is hoped, be expressed and discussed more rigorously through formalization. Also, dialogue properties may be explored through experimentation with implemented formalizations or through formal analysis. HCI researchers have been naturally led to questions such as : Can dialogues be speciied formally? If so, what sort of language is required to specify them? Are the formalizations readily understandable by humans? Once developed, are they easy to maintain and update? Can we prove useful properties of them? Can there be a generic \dialogue manager" for exploring designs interactively. Can the designs be used at least semi-automatically in deriving implementations suitable for end users? Are there generic principles of dialogue design? One The investigation which is the subject of this report was carried out under the terms of