Giancarlo Cherchi

An Agent Architecture for Planning in a Dynamic Environment

This paper briefly describes a scalable architecture for implementing autonomous agents that act in a virtual world created for a computer game and must interact with it by suitably planning and executing actions in a dynamic and not-completely accessible environment. In particular, we are experimenting a two-pass vertically layered architecture that allows supporting an agent behavior through a clean hierarchical organization.

Planning by Abstraction Using HW

This paper presents the parametric system HW[], devised and implemented to perform planning by abstraction. The parameter is an external PDDL-compliant planner, which is exploited to search for solutions at any required level of abstraction including the ground one. To represent abstraction hierarchies an extension to the standard PDDL notation has been devised, which allows one to control communication between adjacent levels by specifying suitable translation rules. Moreover, a novel semi-automatic technique for generating abstract spaces is also described. Five domains -taken from the AIPS 2002, 2000 and 1998 planning competitions- have been selected as test bed. To assess the impact of abstraction techniques on search performances, experiments have been focused on comparing three relevant planners with their hierarchical counterparts. Results put into evidence that the hierarchical approach may significantly speed up the search.