HTN Problem Spaces: Structure, Algorithms, Termination
نویسندگان
چکیده
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 conditions can be evaluated up-front to see if an HTN planning prob-
منابع مشابه
Heuristic Search in Infinite State Spaces Guided by Lyapunov Analysis
In infinite state spaces, many standard heuristic search algorithms do not terminate if the problem is unsolvable. Under some conditions, they can fail to terminate even when there are solutions. We show how techniques from control theory, in particular Lyapunov stability analysis, can be employed to prove the existence of solution paths and provide guarantees that search algorithms will find t...
متن کاملTight Bounds for HTN Planning
Although HTN planning is in general undecidable, there are many syntactically identifiable sub-classes of HTN problems that can be decided. For these sub-classes, the decision procedures provide upper complexity bounds. Lower bounds were often not investigated in more detail, however. We generalize a propositional HTN formalization to one that is based upon a function-free first-order logic and...
متن کاملLearning HTN Method Preconditions and Action Models from Partial Observations
To apply hierarchical task network (HTN) planning to real-world planning problems, one needs to encode the HTN schemata and action models beforehand. However, acquiring such domain knowledge is difficult and time-consuming because the HTN domain definition involves a significant knowledge-engineering effort. A system that can learn the HTN planning domain knowledge automatically would save time...
متن کاملSymbolic Algorithms for Infinite-State Games
A procedure for the analysis of state spaces is called symbolic if it manipulates not individual states, but sets of states that are represented by constraints. Such a procedure can be used for the analysis of infinite state spaces, provided termination is guaranteed. We present symbolic procedures, and corresponding termination criteria, for the solution of infinite-state games, which occur in...
متن کاملSymbolic Algorithms for In nite-State Games?
A procedure for the analysis of state spaces is called sym bolic if it manipulates not individual states but sets of states that are represented by constraints Such a procedure can be used for the analysis of in nite state spaces provided termination is guaranteed We present symbolic procedures and corresponding termination criteria for the so lution of in nite state games which occur in the co...
متن کامل