We describe the modular architecture of a generic dialogue system that
assists a user/operator in performing a task with a tool. This coachi
ng system is named CALLIOPE after the Greek goddess of eloquence. It a
ims at being an active partner in an intelligent man-machine dialogue.
The intelligent dimension of the coaching system is reflected by its
ability to adapt to the user and the situation at hand. The CALLIOPE s
ystem contains an explicit user model and world model to situate its d
ialogue actions. A plan library allows it to follow loosely predetermi
ned dialogue scenarios. The heart of the coaching system is an Al plan
ning module, which plans a series of dialogue actions. We present a co
herent set of three dialogue or speech actions that will make up the p
hysical form of the man-machine communication. The use of the AI plann
ing paradigm as a basis for man-machine interaction is motivated by re
search in various disciplines, as e.g., AI, Cognitive Science and Soci
al Sciences. Starting from the man-man communication metaphor, we can
view the ''thinking before speaking'' of a human communication partner
as constructing an underlying plan which is responsible for the purpo
siveness, the organisation and the relevance of the communication. CAL
LIOPE has been fully implemented and tested on theoretical examples. A
t present, also three tailored versions of CALLIOPE are in operational
use in different industrial application domains: operator support for
remedying-tasks in chemical process industry, operator support for a
combined task of planning, plan execution and process control in the a
rea of chemical process development, and thirdly decision support in p
roduction scheduling.