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29
Maintaining generalized arc consistency on adhoc nary boolean constraints
 IN ECAI06
, 2006
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Structuring Techniques for Constraint Satisfaction Problems
 In Proceedings of the Fifteenth International Joint Conference on Artificial Intelligence
, 1997
"... We present a structuring method for discrete constraint satisfaction problems (CSPs). It takes advantage of interchangeabilities to represent sets of equivalent values by metavalues and thus obtain more compact representations. Strongly related variables are clustered into metavariables to create ..."
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Cited by 11 (6 self)
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We present a structuring method for discrete constraint satisfaction problems (CSPs). It takes advantage of interchangeabilities to represent sets of equivalent values by metavalues and thus obtain more compact representations. Strongly related variables are clustered into metavariables to create occurrences of interchangeabilities. By iterative application, a CSP can be transformed into an hierarchy of equivalent CSPs, where each problem is significantly simpler than the original one. This structure is particularly advantageous when a large set of possible solutions must be inspected. 1 Introduction We consider binary CSPs defined by P = (X; D;C;R), where X = fX 1 ; : : : ; Xng is a set of variables, D = fD 1 ; : : : ; Dng a set of finite domains associated with the variables, C = fC 1 ; : : : ; Cm g a set of constraints, and R =fR ij ` D i \Theta D j for C ij applicable to X i and X j g a set of relations that define the value combinations allowed by the constraints. Solving s...
A Disjunctive Decomposition Control Schema for Constraint Satisfaction
 In Principles and Practice of Constraint Programming, 1st International Workshop, PPCP’93
, 1995
"... The paper presents a control schema for constraint satisfaction. Several algorithms, old and new, are formulated as instances of this schema by specifying different methods of problem decomposition. This formulation facilitates description and comparison of the algorithms and suggests directions for ..."
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Cited by 7 (1 self)
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The paper presents a control schema for constraint satisfaction. Several algorithms, old and new, are formulated as instances of this schema by specifying different methods of problem decomposition. This formulation facilitates description and comparison of the algorithms and suggests directions for further research. A new decomposition method is presented that is virtually guaranteed to reduce problem size, while always retaining at least one of the solutions to the original problem. 1 Introduction A solution to a constraint satisfaction problem (CSP) is an assignment of a value to each problem variable that satisfies all the constraints, or restrictions, on which combinations of variables are permitted. We will focus here on binary CSPs where the constraints involve two variables. The potential values for a variable constitute its domain. We will assume finite domains. We propose a disjunctive divide and conquer control schema for constraint satisfaction. The schema encompasses a wid...
A Method of Program Understanding using Constraint Satisfaction for Software Reverse Engineering
, 1996
"... The process of understanding a source code in a highlevel programming language is a complex cognitive task. The provision of helpful decision aid subsystems would be of great benefit to software maintainers. Given a library of program plan templates, generating a partial understanding of a piece of ..."
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Cited by 5 (2 self)
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The process of understanding a source code in a highlevel programming language is a complex cognitive task. The provision of helpful decision aid subsystems would be of great benefit to software maintainers. Given a library of program plan templates, generating a partial understanding of a piece of software source code can be shown to correspond to the construction of mappings between segments of the source code and particular program plans represented in a library of domain source programs (plans). These mappings can be used as part of the larger task of reverse engineering source code, to facilitate many software engineering tasks such as software reuse, and for program maintenance. We present a novel model of program understanding using constraint satisfaction. The model composes a partial global picture of source program code by transforming knowledge about the problem domain and the program structure into constraints. These constraints facilitate the efficient construction of ma...
Neighborhood Interchangeability and Dynamic Bundling for NonBinary Finite CSPs
 In Joint Annual Workshop of ERCIM/CoLogNet on Constraint Solving and Constraint Logic Programming (CSCLP 04
, 2004
"... Neighborhood Interchangeability (NI) identifies the equivalent values in the domain of a variable of a Constraint Satisfaction Problem (CSP) by considering only the constraints that directly apply to the variable. Freuder described an algorithm for efficiently computing NI values in binary CSPs. In ..."
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Cited by 5 (1 self)
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Neighborhood Interchangeability (NI) identifies the equivalent values in the domain of a variable of a Constraint Satisfaction Problem (CSP) by considering only the constraints that directly apply to the variable. Freuder described an algorithm for efficiently computing NI values in binary CSPs. In this paper, we show that the generalization of this algorithm to nonbinary CSPs is not straightforward, and introduce an efficient algorithm for computing NI values in the presence of nonbinary constraints. Further, we show how to interleave this mechanism with search for solving CSPs, thus yielding a dynamic bundling strategy. While the goal of dynamic bundling is to produce multiple robust solutions, we empirically show that it does not increase (but significantly decreases) the cost of search. 1
Techniques for Bundling the Solution Space of Finite Constraint Satisfaction Problems
, 2001
"... We study the backtracksearch procedure with forward checking (FCBT) for finding all solutions to a finite Constraint Satisfaction Problem (CSP). We describe ..."
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Cited by 4 (4 self)
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We study the backtracksearch procedure with forward checking (FCBT) for finding all solutions to a finite Constraint Satisfaction Problem (CSP). We describe
On the Dynamic Detection of Interchangeability in Finite Constraint Satisfaction Problems
 In Proceedings of CP2001
, 2001
"... We investigate techniques to discover and exploit problem structure in the form of interchangeability. We enhance the performance of backtrack search with forwardchecking (FCBT) for finding all solutions to a finite Constraint Satisfaction Problem(CSP) with dynamic interchangeability detection ..."
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Cited by 4 (2 self)
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We investigate techniques to discover and exploit problem structure in the form of interchangeability. We enhance the performance of backtrack search with forwardchecking (FCBT) for finding all solutions to a finite Constraint Satisfaction Problem(CSP) with dynamic interchangeability detection and dynamic variable ordering. We evaluate these strategies both theoretically and empirically.
Backtrackfree search for realtime constraint satisfaction
 In CP, LNCS 3258
, 2004
"... Abstract. A constraint satisfaction problem (CSP) model can be preprocessed to ensure that any choices made will lead to solutions, without the need to backtrack. This can be especially useful in a realtime process control or online interactive context. The conventional machinery for ensuring backt ..."
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Cited by 3 (1 self)
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Abstract. A constraint satisfaction problem (CSP) model can be preprocessed to ensure that any choices made will lead to solutions, without the need to backtrack. This can be especially useful in a realtime process control or online interactive context. The conventional machinery for ensuring backtrackfree search, however, adds additional constraints, which may require an impractical amount of space. A new approach is presented here that achieves a backtrackfree representation by removing values. This may limit the choice of solutions, but we are guaranteed not to eliminate them all. We show that in an interactive context our proposal allows the system designer and the user to collaboratively establish the tradeoff in space complexity, solution loss, and backtracks. 1
Neighborhood Interchangeability for NonBinary CSPs & Application to Databases
"... Neighborhood Interchangeability (NI) identifies the equivalent values in the domain of a variable in a Constraint Satisfaction Problem (CSP). We introduce for the first time an algorithm for computing NI sets in the presence of nonbinary constraints. We integrate this mechanism with backtrack searc ..."
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Cited by 1 (1 self)
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Neighborhood Interchangeability (NI) identifies the equivalent values in the domain of a variable in a Constraint Satisfaction Problem (CSP). We introduce for the first time an algorithm for computing NI sets in the presence of nonbinary constraints. We integrate this mechanism with backtrack search, in a process we call dynamic bundling. We demonstrate that, as for the binary case [Beckwith et al., 2001], dynamic bundling yields multiple robust solutions for less effort than necessary for computing a single solution. We then identify the utility of this mechanism for database applications and introduce a new algorithm based on dynamic bundling for computing a join query, which we model as a CSP. We argue that the algorithm yields a compact solution space and saves memory, diskspace, and/or network bandwidth. Finally, we discuss the application of the join algorithm to materialize views. ACKNOWLEDGEMENTS I would like to thank my advisor, Professor Berthe Y. Choueiry, for her tireless support and guidance since the beginning of this research. Without her help this work would not have been possible. I would like to thank my committee members, Professors Matthew
Intelligent Domain Splitting for CSPs with Ordered Domains
, 1999
"... This paper presents intelligent domain splitting, an approach for searching in CSPs with ordered domains. The technique has a particular strength for finding all solutions. It represents the search space by aggregations obtained through the cooperation of two known clustering concepts, namely interv ..."
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Cited by 1 (0 self)
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This paper presents intelligent domain splitting, an approach for searching in CSPs with ordered domains. The technique has a particular strength for finding all solutions. It represents the search space by aggregations obtained through the cooperation of two known clustering concepts, namely intervals and crossproducts. Intelligent domain splitting searches for solutions by iteratively breaking up the space into smaller subspaces in a meaningful way. The proposed backtracking technique benefits from the strengths of Hullconsistency (i.e. 2Bconsistency [4]) and of the Cartesian product representation [2]. The algorithm can be applied to general systems of constraints with explicit representations. Even though designed for generating all solutions, it also proves useful for finding the first solution of hard problems, as shown by preliminary experiments