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111
Approximate Policy Iteration with a Policy Language Bias
 Journal of Artificial Intelligence Research
, 2003
"... We explore approximate policy iteration (API), replacing the usual costfunction learning step with a learning step in policy space. We give policylanguage biases that enable solution of very large relational Markov decision processes (MDPs) that no previous technique can solve. ..."
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Cited by 141 (18 self)
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We explore approximate policy iteration (API), replacing the usual costfunction learning step with a learning step in policy space. We give policylanguage biases that enable solution of very large relational Markov decision processes (MDPs) that no previous technique can solve.
Exploiting Structure to Efficiently Solve Large Scale Partially Observable Markov Decision Processes
, 2005
"... Partially observable Markov decision processes (POMDPs) provide a natural and principled framework to model a wide range of sequential decision making problems under uncertainty. To date, the use of POMDPs in realworld problems has been limited by the poor scalability of existing solution algorithm ..."
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Cited by 91 (6 self)
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Partially observable Markov decision processes (POMDPs) provide a natural and principled framework to model a wide range of sequential decision making problems under uncertainty. To date, the use of POMDPs in realworld problems has been limited by the poor scalability of existing solution algorithms, which can only solve problems with up to ten thousand states. In fact, the complexity of finding an optimal policy for a finitehorizon discrete POMDP is PSPACEcomplete. In practice, two important sources of intractability plague most solution algorithms: large policy spaces and large state spaces. On the other hand,
Learning to win: Casebased plan selection in a realtime strategy game
 in Proceedings of the Sixth International Conference on CaseBased Reasoning
, 2005
"... Abstract. While several researchers have applied casebased reasoning techniques to games, only Ponsen and Spronck (2004) have addressed the challenging problem of learning to win realtime games. Focusing on WARGUS, they report good results for a genetic algorithm that searches in plan space, and f ..."
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Cited by 85 (10 self)
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Abstract. While several researchers have applied casebased reasoning techniques to games, only Ponsen and Spronck (2004) have addressed the challenging problem of learning to win realtime games. Focusing on WARGUS, they report good results for a genetic algorithm that searches in plan space, and for a weighting algorithm (dynamic scripting) that biases subplan retrieval. However, both approaches assume a static opponent, and were not designed to transfer their learned knowledge to opponents with substantially different strategies. We introduce a plan retrieval algorithm that, by using three key sources of domain knowledge, removes the assumption of a static opponent. Our experiments show that its implementation in the Casebased Tactician (CAT) significantly outperforms the best among a set of genetically evolved plans when tested against random WARGUS opponents. CAT communicates with WARGUS through TIELT, a testbed for integrating and evaluating decision systems with simulators. This is the first application of TIELT. We describe this application, our lessons learned, and our motivations for future work. 1
Transfer learning via intertask mappings for temporal difference learning
 Journal of Machine Learning Research
"... Temporal difference (TD) learning (Sutton and Barto, 1998) has become a popular reinforcement learning technique in recent years. TD methods, relying on function approximators to generalize learning to novel situations, have had some experimental successes and have been shown to exhibit some desirab ..."
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Cited by 64 (20 self)
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Temporal difference (TD) learning (Sutton and Barto, 1998) has become a popular reinforcement learning technique in recent years. TD methods, relying on function approximators to generalize learning to novel situations, have had some experimental successes and have been shown to exhibit some desirable properties in theory, but the most basic algorithms have often been found slow in practice. This empirical result has motivated the development of many methods that speed up reinforcement learning by modifying a task for the learner or helping the learner better generalize to novel situations. This article focuses on generalizing across tasks, thereby speeding up learning, via a novel form of transfer using handcoded task relationships. We compare learning on a complex task with three function approximators, a cerebellar model arithmetic computer (CMAC), an artificial neural network (ANN), and a radial basis function (RBF), and empirically demonstrate that directly transferring the actionvalue function can lead to a dramatic speedup in learning with all three. Using transfer via intertask mapping (TVITM), agents are able to learn one task and then markedly reduce the time it takes to learn a more complex task. Our algorithms are fully implemented and tested in the RoboCup soccer Keepaway domain. This article contains and extends material published in two conference papers (Taylor and Stone, 2005; Taylor et al., 2005).
Transfer Learning for Reinforcement Learning Domains: A Survey
"... The reinforcement learning paradigm is a popular way to address problems that have only limited environmental feedback, rather than correctly labeled examples, as is common in other machine learning contexts. While significant progress has been made to improve learning in a single task, the idea of ..."
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Cited by 49 (6 self)
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The reinforcement learning paradigm is a popular way to address problems that have only limited environmental feedback, rather than correctly labeled examples, as is common in other machine learning contexts. While significant progress has been made to improve learning in a single task, the idea of transfer learning has only recently been applied to reinforcement learning tasks. The core idea of transfer is that experience gained in learning to perform one task can help improve learning performance in a related, but different, task. In this article we present a framework that classifies transfer learning methods in terms of their capabilities and goals, and then use it to survey the existing literature, as well as to suggest future directions for transfer learning work.
Exploiting FirstOrder Regression in Inductive Policy Selection
 Proceedings of the Twentieth Conference on Uncertainty in Artificial Intelligence (UAI’04
, 2004
"... We consider the problem of computing optimal generalised policies for relational Markov decision processes. We describe an approach combining some of the benefits of purely inductive techniques with those of symbolic dynamic programming methods. The latter reason about the optimal value function usi ..."
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Cited by 47 (2 self)
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We consider the problem of computing optimal generalised policies for relational Markov decision processes. We describe an approach combining some of the benefits of purely inductive techniques with those of symbolic dynamic programming methods. The latter reason about the optimal value function using firstorder decisiontheoretic regression and formula rewriting, while the former, when provided with a suitable hypotheses language, are capable of generalising value functions or policies for small instances. Our idea is to use reasoning and in particular classical firstorder regression to automatically generate a hypotheses language dedicated to the domain at hand, which is then used as input by an inductive solver. This approach avoids the more complex reasoning of symbolic dynamic programming while focusing the inductive solver’s attention on concepts that are specifically relevant to the optimal value function for the domain considered. 1
ValueFunctionBased transfer for reinforcement learning using structure mapping
 Proceedings of the 21st Association for the Advancement of Artificial Intelligence
, 2006
"... Transfer learning concerns applying knowledge learned in one task (the source) to improve learning another related task (the target). In this paper, we use structure mapping, a psychological and computational theory about analogy making, to find mappings between the source and target tasks and thus ..."
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Cited by 47 (7 self)
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Transfer learning concerns applying knowledge learned in one task (the source) to improve learning another related task (the target). In this paper, we use structure mapping, a psychological and computational theory about analogy making, to find mappings between the source and target tasks and thus construct the transfer functional automatically. Our structure mapping algorithm is a specialized and optimized version of the structure mapping engine and uses heuristic search to find the best maximal mapping. The algorithm takes as input the source and target task specifications represented as qualitative dynamic Bayes networks, which do not need probability information. We apply this method to the Keepaway task from RoboCup simulated soccer and compare the result from automated transfer to that from handcoded transfer.
Bellman goes Relational
 In ICML
, 2004
"... Motivated by the interest in relational reinforcement learning, we introduce a novel relational Bellman update operator called ReBel. It employs a constraint logic programming language to compactly represent Markov decision processes over relational domains. ..."
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Cited by 46 (3 self)
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Motivated by the interest in relational reinforcement learning, we introduce a novel relational Bellman update operator called ReBel. It employs a constraint logic programming language to compactly represent Markov decision processes over relational domains.
K.: Relational reinforcement learning: An overview
 In: Proceedings of the ICML’04 Workshop on Relational Reinforcement Learning
, 2004
"... Relational Reinforcement Learning (RRL) is both a young and an old eld. In this paper, we trace the history of the eld to related disciplines, outline some current work and promising new directions, and survey the research issues and opportunities that lie ahead. 1. ..."
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Cited by 39 (3 self)
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Relational Reinforcement Learning (RRL) is both a young and an old eld. In this paper, we trace the history of the eld to related disciplines, outline some current work and promising new directions, and survey the research issues and opportunities that lie ahead. 1.
Approximate linear programming for firstorder MDPs
 In Proc. UAI05, 509– 517
, 2005
"... We introduce a new approximate solution technique for firstorder Markov decision processes (FOMDPs). Representing the value function linearly w.r.t. a set of firstorder basis functions, we compute suitable weights by casting the corresponding optimization as a firstorder linear program and show h ..."
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Cited by 37 (9 self)
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We introduce a new approximate solution technique for firstorder Markov decision processes (FOMDPs). Representing the value function linearly w.r.t. a set of firstorder basis functions, we compute suitable weights by casting the corresponding optimization as a firstorder linear program and show how offtheshelf theorem prover and LP software can be effectively used. This technique allows one to solve FOMDPs independent of a specific domain instantiation; furthermore, it allows one to determine bounds on approximation error that apply equally to all domain instantiations. We apply this solution technique to the task of elevator scheduling with a rich feature space and multicriteria additive reward, and demonstrate that it outperforms a number of intuitive, heuristicallyguided policies. 1