On Hierarchical Task Networks

Abstract

OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible. Abstract. In planning based on hierarchical task networks (HTN), plans are generated by refining high-level actions ('compound tasks') into lower-level actions, until primitive actions are obtained that can be sent to execution. While a primitive action is defined by its precondition and effects, a high-level action is defined by zero, one or several methods: sets of (high-level or primitive) actions decomposing it together with a constraint. We give a semantics of HTNs in terms of dynamic logic with program inclusion. We propose postulates guaranteeing soundness and completeness of action refinement. We also show that hybrid planning can be analysed in the same dynamic logic framework.

Deciding Refinement Relation in Belief-Intention Databases

“…Considering refinement in a derived way helps us to complete the refinement ways by discovering the implicit refinement relation between actions. Postulates of the soundness and completeness for refining actions were proposed in [12] and we believe, they provide rational postulates for improving the HTN domains.…”

Refinement of Intentions

“…More general expansion may lead to unsatisfiable database and raises issues about withdrawal or revision of intentions. This is further explored in [13]. The next step is to investigate the revision of belief-intention databases.…”

BDI Logics for BDI Architectures: Old Problems, New Perspectives

“…Characterizing such effect is not trivial, as it raises the question of the main ('primary') effect [38] of an action. We propose a logical approach in [32]. Mixing BDI reasoning and hybrid planning has been proposed in [24]: this work is a promising starting point even if the primary effect of an action is not clearly characterized.…”