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Proceedings ArticleDOI

Nogood Recording for static and dynamic constraint satisfaction problems

TLDR
A new class of constraint recording algorithms called Nogood Recording is proposed that may be used for solving both static and dynamic CSPs and offers an interesting compromise, polynomially bounded in space, between an ATMS-like approach and the usual static constraint satisfaction algorithms.
Abstract
Many AI synthesis problems such as planning, scheduling or design may be encoded in a constraint satisfaction problem (CSP). A CSP is typically defined as the problem of finding any consistent labeling for a fixed set of variables satisfying all given constraints between these variables. However, for many real tasks, the set of constraints to consider may evolve because of the environment or because of user interactions. The problem considered here is the solution maintenance problem in such a dynamic CSP (DCSP). The authors propose a new class of constraint recording algorithms called Nogood Recording that may be used for solving both static and dynamic CSPs. It offers an interesting compromise, polynomially bounded in space, between an ATMS-like approach and the usual static constraint satisfaction algorithms.

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Citations
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Journal ArticleDOI

GRASP: a search algorithm for propositional satisfiability

TL;DR: Experimental results obtained from a large number of benchmarks indicate that application of the proposed conflict analysis techniques to SAT algorithms can be extremely effective for aLarge number of representative classes of SAT instances.
Proceedings Article

Solution reuse in dynamic constraint satisfaction problems

TL;DR: A method for reusing any previous solution and producing a new one by local changes on the previous one, either from an empty assignment, or from any previous assignment is proposed and how it can be improved using filtering or learning methods, such as forward-checking or nogood-recording.
Proceedings Article

Local Search with Constraint Propagation and Conflict-Based Heuristics

TL;DR: This paper presents a new hybrid technique that performs a local search over partial assignments instead of complete assignments, and uses filtering techniques and conflict-based techniques to efficiently guide the search.
Journal ArticleDOI

A theoretical evaluation of selected backtracking algorithms

TL;DR: A notion of inconsistency between instantiations and variables is introduced, and is shown to be a useful tool for characterizing such well-known concepts as backtrack, backjump, and domain annihilation.
Book

Constraint Networks: Techniques and Algorithms

TL;DR: This book provides an accessible synthesis of the author's research and work in this area, divided into four main topics: representation, inference, search, and learning.
References
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Journal ArticleDOI

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Proceedings Article

Where the really hard problems are

TL;DR: It is shown that NP-complete problems can be summarized by at least one "order parameter", and that the hard problems occur at a critical value of such a parameter.
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TL;DR: In this article, the min-conflicts heuristic is used to minimize the number of constraint violations after each step in a value-ordering heuristic search, which can be used with a variety of different search strategies.
Journal ArticleDOI

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TL;DR: This paper presents an approach that allows base algorithms to be combined, giving us new hybrids, and it is shown that FC‐CBJ is by far the best of the algorithms examined.
Journal ArticleDOI

Enhancement schemes for constraint processing: backjumping, learning, and cutset decomposition

TL;DR: An integrated strategy is described which utilizes the distinct advantages of each scheme and shows that, in hard problems, the average improvement realized by the integrated scheme is 20–25% higher than any of the individual schemes.