Results 1  10
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12
Learning Abstraction Hierarchies for Problem Solving
, 1990
"... The use of abstraction in problem solving is an effective approach to reducing search, but finding good abstractions is a difficult problem, even for people. This paper identifies a criterion for selecting useful abstractions, describes a tractable algorithm for generating them, and empirically ..."
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Cited by 82 (6 self)
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The use of abstraction in problem solving is an effective approach to reducing search, but finding good abstractions is a difficult problem, even for people. This paper identifies a criterion for selecting useful abstractions, describes a tractable algorithm for generating them, and empirically demonstrates that the abstractions reduce search. The abstraction learner, called alpine,isinte grated with the prodigy problem solver [Minton et al., 1989b, Carbonell et al.,1991] and has been tested on large problem sets in multiple domains.
ABTWEAK: Abstracting a nonlinear, least commitment planner
 In Proceedings of the Eighth National Conference on Artificial Intelligence
, 1990
"... We present the system AbTweak, which extends the preconditionelimination abstraction of Abstrips to hierarchical planners using the nonlinear plan representation as de ned in Tweak. We show that AbTweak satis es the monotonic property, whereby the existence of a lowest level solution implies the ex ..."
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Cited by 52 (10 self)
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We present the system AbTweak, which extends the preconditionelimination abstraction of Abstrips to hierarchical planners using the nonlinear plan representation as de ned in Tweak. We show that AbTweak satis es the monotonic property, whereby the existence of a lowest level solution implies the existence of a highest level solution that is structurally similar to. This property enables one to prune a considerable amount of the search space without loss of completeness. Abstracting Planning Systems Abstraction in planning systems can be viewed as a mapping from one problem description (at a concrete level) to another(at the abstract level). There has been a considerable amount of research recently in formalizing intuitions regarding abstraction and the hierarchical problem solving strategies that abstraction gives rise to [Fikes et al., 1972, Knoblock, 1989,
Lifeworld Analysis
 Journal of Artificial Intelligence Research
, 1997
"... We argue that the analysis of agent#environmentinteractions should be extended to include the conventions and invariants maintained by agents throughout their activity. We refer to this thicker notion of environmentasalifeworld and present a partial set of formal tools for describing structures o ..."
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Cited by 35 (0 self)
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We argue that the analysis of agent#environmentinteractions should be extended to include the conventions and invariants maintained by agents throughout their activity. We refer to this thicker notion of environmentasalifeworld and present a partial set of formal tools for describing structures of lifeworlds and the ways in which they computationally simplify activity. As one speci#c example, we apply the tools to the analysis of the Toast system and showhowversions of the system with very di#erent control structures in fact implement a common control structure together with di#erent conventions for encoding task state in the positions or states of objects in the environment.
Equivalence and Tractability Results for SAS+ Planning
 Proceedings of the 3rd International Conference on Principles on Knowledge Representation and Reasoning (KR92
, 1992
"... We define the SAS + planning formalism, which generalizes the previously presented SAS formalism. The SAS + formalism is compared with some betterknown propositionalplanning formalisms with respect to expressiveness. Contrary to intuition, all formalisms turn out to be equally expressive in a v ..."
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Cited by 22 (6 self)
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We define the SAS + planning formalism, which generalizes the previously presented SAS formalism. The SAS + formalism is compared with some betterknown propositionalplanning formalisms with respect to expressiveness. Contrary to intuition, all formalisms turn out to be equally expressive in a very strong sense. We further present the SAS + PUS planning problem which generalizes the previously presented, tractable SASPUS problem. We prove that also the SAS +  PUS problem is tractable by devising a provably correct polynomial time algorithm for this problem. 1 Introduction Much effort has gone into finding more and more general formalisms, mainly logicbased, for plans and actions and also into finding reasoning methods for these. Although such formalisms may be important for modelling problems and comparing different approaches we most probably have to identify subproblems and devise tailored algorithms for these in order to overcome the computational difficulties involved. ...
Automated hierarchy discovery for planning in partially observable domains
 Advances in Neural Information Processing Systems 19
, 2006
"... author of this thesis. This is a true copy of the thesis, including any required final revisions, as accepted by my examiners. I understand that my thesis may be made electronically available to the public. ..."
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Cited by 10 (2 self)
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author of this thesis. This is a true copy of the thesis, including any required final revisions, as accepted by my examiners. I understand that my thesis may be made electronically available to the public.
Relevance Reasoning to Guide Compositional Modeling
, 1992
"... The ability to choose an appropriate manner in which to model a given device is crucial in making a compositional modeling [3] approach successful. In compositional modeling, a system is provided with a library of composible pieces of knowledge about the physical world, called model fragments, ea ..."
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Cited by 9 (0 self)
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The ability to choose an appropriate manner in which to model a given device is crucial in making a compositional modeling [3] approach successful. In compositional modeling, a system is provided with a library of composible pieces of knowledge about the physical world, called model fragments, each representing a conceptually distinct phenomenon such as a physical process or one aspect of a component behavior. Given a specific query about a device, the system chooses among those model fragments to compose a model of the device that is most adequate to answer the query. Selection of appropriate model fragments can be viewed as a special case of a more general problem of reasoning about relevance of knowledge to a given goal. In this paper we pursue this view by applying a general framework for reasoning about relevance to the problem of model fragment selection. We show that heuristics for model selection can be usefully stated as irrelevance claims. Employing such a framew...
Boundary Region Relations
, 1998
"... We are interested in the problem of how an agent organizes its sensorimotor experiences in order to create a spatial representation. Our approachto solve this problem is the Spatial Semantic Hierarchy #SSH#, where multiple levels of spatial representation coexists. At the SSH topological level, ..."
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Cited by 5 (4 self)
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We are interested in the problem of how an agent organizes its sensorimotor experiences in order to create a spatial representation. Our approachto solve this problem is the Spatial Semantic Hierarchy #SSH#, where multiple levels of spatial representation coexists. At the SSH topological level, space is represented by places and connectivity relation among them. Places are arranged into streets so that the topological representation looks like the street network of a city.
A PatternWeight Formulation of Search Knowledge
 Computational Intelligence
, 1994
"... this paper begins to address. ..."
Abstracting the Tower of Hanoi
 IN WORKING NOTES OF AAAI90 WORKSHOP ON AUTOMATIC GENERATION OF APPROXIMATIONS AND ABSTRACTIONS
, 1990
"... This paper describes an automated approach to generating abstractions for the Tower of Hanoi and analyzes the use of these abstractions for problem solving. The analysis shows that the learned abstractions produce an exponential reduction in the size of the search space. Since few problem solvers ..."
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Cited by 4 (1 self)
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This paper describes an automated approach to generating abstractions for the Tower of Hanoi and analyzes the use of these abstractions for problem solving. The analysis shows that the learned abstractions produce an exponential reduction in the size of the search space. Since few problem solvers actually explore the entire search space, the paper also presents an empirical analysis of the speedup provided by abstraction when a heuristic searchisemployed. The empirical analysis shows that the benefit of abstraction is largely determined by the portion of the baselevel search space explored. Thus, using breadthfirst search, which searches the entire space, abstraction provides an exponential reduction in search. However, using a depthfirst search, the search reduction is smaller and depends on the amount of backtracking required to solve the problem.
Model Based Knowledge Organization
"... Reasoning about the behaviour of large industrial processes is a difficult and complex computational task. To perform it efficiently requires the use of numerous specialized representations of the system. Any successful information processing system in suchanenvironmentmust have effective ways to ma ..."
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Reasoning about the behaviour of large industrial processes is a difficult and complex computational task. To perform it efficiently requires the use of numerous specialized representations of the system. Any successful information processing system in suchanenvironmentmust have effective ways to manage these representations, the individual reasoning tasks which use them, and the flow of information between them. This paper addresses these issues by proposing a model centered view of knowledge and presents a domain independent representation language along with operators for managing multiple overlapping models of dynamic physical systems. Examples are given of its use in sensor interpretation, diagnosis and planning in a simple pipeandtank network. INTRODUCTION This paper presents a domain independentscheme for representing and manipulating models of dynamic physical systems. It is intended for applications in which one physical system is the focus of a diverse set of reasoning ...