This tutorial will start by presenting a common core of the various existing logical languages for expressing action effects, and will then focus on computational issues: we will see how progression, weak regression and strong regression can be computed in practice, and how they can be used for plan verification and generation. Two classes of actions will be considered: `physical' actions, aiming at changing the state of the world, and 'epistemic' (or 'sensing') actions, aiming at gathering new knowledge about the state of the world. (If time permits, we'll consider as well communication actions in a multiagent framework).
Although interest in natural language interfaces to databases has waned in recent years, a new emphasis on closed domain question answering presages a revival. This tutorial addresses this long standing problem. We shall start with a critical review of prior work, mainly carried out in the 1980's. Next we shall identify recent advances in database and language technology that might enable better solutions. Finally we shall review several state of the art systems to characterize current approaches.