Most practical work on AI planning systems during the last fifteen years has been based on hierarchical task network (HTN) d ecomposition, but until now, there has been very little analytical work on the properties of HTN planners. This paper describes how the complexity of HTN planning varies with various conditions on the task networks. networks are required to be totally ordered, and (3) whe...

Abstract This study was intended to compare collaborative and individual task planning effects on Iranian EFL learners’ writing performance. Therefore, a group of 90 upper intermediate EFL learners were placed in three groups of Collaborative Task planning, Individual Task planning, and Control. In the experimental groups, participants were asked to do task planning collaboratively and individu...

Abstract This study was intended to compare collaborative and individual task planning effects on Iranian EFL learners’ writing performance. Therefore, a group of 90 upper intermediate EFL learners were placed in three groups of Collaborative Task planning, Individual Task planning, and Control. In the experimental groups, participants were asked to do task planning collaboratively and individu...

Although task reduction (HTN) planning historically preceded partial order (PO) planning, and is understood to be more general than the latter, very little analysis has been done regarding its performance. Part of the reason for this has been the lack of systematic understanding of the functionalities provided by HTN planning over and above that of partial order planning. HTN planning has been ...

Research evidence reported to date demonstrates the differential effects of manipulating second language (L2) task conditions on the resultant production as measured in terms of complexity, accuracy, and fluency. The present study was aimed at adding to the available body of findings by exploring the synergistic effects of two task condition variables, namely online planning and immediacy (± He...

Casting planning problems as propositional satlsfiability problems has recently been shown to be an effective way of scaling up plan synthesis. Until now, the benefits of this approach have only been utUized in primitive action-based planning models. Motivated by the conventional wisdom in the planning community about the effectiveness of hierarchical task network (HTN) planning models, in this...

For HTN planning, we formally characterize and classify four kinds of problem spaces in which each node represents a planning problem or subproblem. Two of the problem spaces are searched by current HTN planning algorithms; the other two problem spaces are new. This enables us to provide: • Sufficient (and in one case, necessary) conditions for finiteness of each kind of problem space. The cond...