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Heuristic Search Planner 2.0

AI Magazine

This general planner implements a scheduler that tries different variants concurrently with different (time) resource bounds. We also describe how hsp2.0 can be used as an optimal (and near-optimal) planning algorithm and compare its performance with two other optimal planners, stan and blackbox.


Stan4: A Hybrid Planning Strategy Based on Subproblem Abstraction

AI Magazine

Planning domains often feature subproblems such as route planning and resource handling. Using static domain analysis techniques, we have been able to identify certain commonly occurring subproblems within planning domains, making it possible to abstract these subproblems from the overall goals of the planner and deploy specialized technology to handle them in a way integrated with the broader planning activities. Using two such subsolvers our hybrid planner, stan4, participated successfully in the Fifth International Conference on Artificial Intelligence Planning and Scheduling (AIPS'00) planning competition.


FF: The Fast-Forward Planning System

AI Magazine

Fast-forward (FF) was the most successful automatic planner in the Fifth International Conference on Artificial Intelligence Planning and Scheduling (AIPS '00) planning systems competition. Like the well-known hsp system, FF relies on forward search in the state space, guided by a heuristic that estimates goal distances by ignoring delete lists. It differs from HSP in a number of important details. This article describes the algorithmic techniques used in FF in comparison to hsp and evaluates their benefits in terms of run-time and solution-length behavior.


MIPS: The Model-Checking Integrated Planning System

AI Magazine

Mips is a planning system that applies binary decision diagrams (BDDs) to compactly represent world states in a planning problem and efficiently explore the underlying state space. It was the first general planning system based on model-checking methods. At the Fifth International Conference on Artificial Intelligence Planning and Scheduling (AIPS'00), mips was one of five planning systems to be awarded for distinguished performance in the fully automated track. This article gives a brief introduction to, and explains the basic planning algorithm used by, mips, using a simple logistics problem as an example.


Creativity at the Metalevel: AAAI-2000 Presidential Address

AI Magazine

Creativity is sometimes taken to be an inexplicable aspect of human activity. By summarizing a considerable body of literature on creativity, I hope to show how to turn some of the best ideas about creativity into programs that are demonstrably more creative than any we have seen to date. I believe the key to building more creative programs is to give them the ability to reflect on and modify their own frameworks and criteria. That is, I believe that the key to creativity is at the metalevel.


The GRT Planner

AI Magazine

This article presents the GRT planner, a forward heuristic state-space planner, and comments on the results obtained from the Fifth International Conference on Artificial Intelligence Planning and Scheduling (AIPS'00) planning competition. The grt planner works in two phases. In the preprocessing phase, it estimates the distances between the facts and the goals of the problem. During the search phase, the estimates are used to guide a forward-directed search.


AltAlt: Combining Graphplan and Heuristic State Search

AI Magazine

We briefly describe the implementation and evaluation of a novel plan synthesis system, called AltAlt. AltAlt is designed to exploit the complementary strengths of two of the currently popular competing approaches for plan generation: (1) graphplan and (2) heuristic state search. It uses the planning graph to derive effective heuristics that are then used to guide heuristic state search. The heuristics derived from the planning graph do a better job of taking the subgoal interactions into account and, as such, are significantly more effective than existing heuristics. AltAlt was implemented on top of two state-of-the-art planning systems: (1) stan3.0, a graphplan-style planner, and (2) hsp-r, a heuristic search planner.


AAAI News

AI Magazine

C. Furniture, Fixtures and Equipment: Effective for 1996 the Association Furniture, fixtures and equipment are has changed its method of accounting stated at cost, less accumulated depreciation.


Planning in the Fluent Calculus Using Binary Decision Diagrams

AI Magazine

BDDplan was created to perform certain reasoning processes in the fluent calculus, a flexible framework for reasoning about action and change based on first-order logic with equality (plus some second-order extensions in some cases). The reasoning is done by mapping the problems into propositional logic, which, in turn, can be implemented as operations on binary decision diagrams (BDDs).


AltAlt: Combining Graphplan and Heuristic State Search

AI Magazine

We briefly describe the implementation and evaluation of a novel plan synthesis system, called AltAlt. AltAlt is designed to exploit the complementary strengths of two of the currently popular competing approaches for plan generation: (1) graphplan and (2) heuristic state search. It uses the planning graph to derive effective heuristics that are then used to guide heuristic state search. The heuristics derived from the planning graph do a better job of taking the subgoal interactions into account and, as such, are significantly more effective than existing heuristics. AltAlt was implemented on top of two state-of-the-art planning systems: (1) stan3.0, a graphplan-style planner, and (2) hsp-r, a heuristic search planner.