EXCALIBUR
Adaptive Constraint-Based Agents in Artificial Environments

[DOMAIN-INDEPENDENT PLANNING]   [Extensions]   [Symbolic SRC]   [Evaluation]

[ Please note: The project has been discontinued as of May 31, 2005 and is superseded by the projects of the ii Labs. There won't be further updates to these pages. ]

Extending the ARC and TC

(Related publication: [PUBLink])

The Action Resource Constraint was introduced in a framework without any possibility of modifying the graph structure. Thus, the potential being extended by the structural constraint satisfaction, the constraint's heuristics can use additional techniques to reduce their inconsistency. A simple extension made here is to include an ARC-H3 heuristic that deletes an action if an Action Task of the action causes an overlap on the resource.

The heuristic selects an Action Task, the choice probability for an Action Task being proportional to the length of all ARC intervals that include the task and are inconsistent. The Task Constraint of the selected Action Task is deleted (together with its tasks).

The planning system will be used in the context of an ongoing time. To force the planning system to schedule Action Tasks that have not yet been started to begin after the Current Time, the Task Constraint is extended to assign inconsistencies to these Action Tasks. The inconsistency is computed as the temporal distance from the Action Task's Begin variable to the Current Time's variable.

No heuristic allows a deletion or a move of an Action Task that is currently under execution.


[DOMAIN-INDEPENDENT PLANNING]   [Extensions]   [Symbolic SRC]   [Evaluation]

For questions, comments or suggestions, please contact us.

Last update:
May 20, 2001 by Alexander Nareyek