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Solving Set Partitioning Problems with Constraint Programming
, 1998
"... This paper investigates the potential of constraint programming for solving set partitioning problems occurring in crew scheduling, where constraint programming is restricted to not employ external solvers, as for instance integer linear programming solvers. We evaluate preprocessing steps known ..."
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Cited by 19 (0 self)
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This paper investigates the potential of constraint programming for solving set partitioning problems occurring in crew scheduling, where constraint programming is restricted to not employ external solvers, as for instance integer linear programming solvers. We evaluate preprocessing steps known from the OR literature on moderately sized set partitioning problems. Further, we propose a new preprocessing technique which allows to reduce problem size more effectively than standard preprocessing techniques but with similar computational effort. Additionally, we propose a propagation algorithm for a global set partitioning constraint which, compared with other constraint programming approaches, finds and proves optimal solutions significantly faster resp. produces better solutions in a given time period.
Soft Constraints for Security Protocol Analysis: Confidentiality
, 2001
"... We model any network configuration arising from the execution of a security protocol as a soft constraint satisfaction problem (SCSP). We formalise the protocol goal of confidentiality as a property of the solution for an SCSP, hence confidentiality always holds with a certain security level. Th ..."
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Cited by 19 (11 self)
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We model any network configuration arising from the execution of a security protocol as a soft constraint satisfaction problem (SCSP). We formalise the protocol goal of confidentiality as a property of the solution for an SCSP, hence confidentiality always holds with a certain security level. The policy SCSP models the network configuration where all admissible protocol sessions have terminated successfully, and an imputable SCSP models a given network configuration. Comparing the solutions of these two problems elicits whether the given configuration hides a confidentiality attack. We can also compare attacks and decide which is the most significant. The approach is demonstrated on the asymmetric NeedhamSchroeder protocol.
Abstracting Soft Constraints: Framework, Properties, Examples
 Artificial Intelligence
, 2002
"... Soft constraints are very exible and expressive. However, they also are very complex to handle. For this reason, it may be reasonable in several cases to pass to an abstract version of a given soft constraint problem, and then to bring some useful information from the abstract problem to the concret ..."
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Cited by 18 (9 self)
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Soft constraints are very exible and expressive. However, they also are very complex to handle. For this reason, it may be reasonable in several cases to pass to an abstract version of a given soft constraint problem, and then to bring some useful information from the abstract problem to the concrete one. This will hopefully make the search for a solution, or for an optimal solution, of the concrete problem, faster.
A Problem Classification Scheme for Finite Domain Constraint Solving
 PROCEEDING OF WORKSHOP ON CONSTRAINT APPLICATIONS, CP96,BOSTON
, 1996
"... In this paper we give a classification of problems solved with finite domain solvers in Constraint Logic Programming (CLP). This scheme tries to explain which types of problems can effectively be solved with CLP and which problems are best solved with competing techniques like integer programming or ..."
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Cited by 18 (5 self)
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In this paper we give a classification of problems solved with finite domain solvers in Constraint Logic Programming (CLP). This scheme tries to explain which types of problems can effectively be solved with CLP and which problems are best solved with competing techniques like integer programming or local search. The survey is based on industrial studies and applications developed over the last ten years. We also try to find explanations for failures in some projects and give a list of critical issues in problem solving with constraint logic programming.
Extensible Dependency Grammar: A Modular Grammar Formalism Based On Multigraph Description
, 2006
"... This thesis develops Extensible Dependency Grammar (XDG), a new grammar formalism combining dependency grammar, modeltheoretic syntax, and Jackendoff’s parallel grammar architecture. The design of XDG is strongly geared towards modularity: grammars can be modularly extended by any linguistic aspect ..."
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Cited by 17 (3 self)
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This thesis develops Extensible Dependency Grammar (XDG), a new grammar formalism combining dependency grammar, modeltheoretic syntax, and Jackendoff’s parallel grammar architecture. The design of XDG is strongly geared towards modularity: grammars can be modularly extended by any linguistic aspect such as grammatical functions, word order, predicateargument structure, scope, information structure and prosody, where each aspect is modeled largely independently on a separate dimension. The intersective demands of the dimensions make many complex linguistic phenomena such as extraction in syntax, scope ambiguities in the semantics, and control and raising in the syntaxsemantics interface simply fall out as byproducts without further stipulation. This thesis makes three main contributions: 1. The first formalization of XDG as a multigraph description language in higher order logic, and investigations of its expressivity and computational complexity. 2. The first implementation of XDG, the XDG Development Kit (XDK), an extensive grammar development environment built around a constraint parser for XDG. 3. The first application of XDG to natural language, modularly modeling a fragment of English.
A procedure for mediation of queries to sources in disparate contexts
 In Proceedings of the International Logic Programming Symposium
, 1997
"... This paper discusses the algorithm we are using for the mediation of queries to disparate information sources in a Context Interchange system, where information sources may have di erent interpretations arising from their respective context. Queries are assumed to be formulated without regard for se ..."
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Cited by 16 (11 self)
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This paper discusses the algorithm we are using for the mediation of queries to disparate information sources in a Context Interchange system, where information sources may have di erent interpretations arising from their respective context. Queries are assumed to be formulated without regard for semantic heterogeneity, and are rewritten to corresponding mediated queries by taking into account the semantics of data codi ed in axioms associated with sources and receivers (the corresponding context theories). Our approach draws upon recent advances in abductive logic programming and presents an integration of techniques for query rewriting and semantic query optimization. We also demonstrate how thiscanbe e ciently implemented using the constraint logic programming system ECLiPSe. 1
Integrating Planning and Scheduling
 APPLIED ARTIFICIAL INTELLIGENCE
, 2001
"... Planning and scheduling research is becoming an increasingly interesting topic in the Artificial Intelligence area... ..."
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Cited by 16 (5 self)
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Planning and scheduling research is becoming an increasingly interesting topic in the Artificial Intelligence area...
SemiAutomatic Modeling by Constraint Acquisition
 In Francesca Rossi, editor, International Conference on Principles and Practice of Constraint Programming, number 2833 in LNCS
, 2003
"... Constraint programming is a technology which is now widely used to solve combinatorial problems in industrial applications. However, using it requires considerable knowledge and expertise in the field of constraint reasoning. ..."
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Cited by 13 (3 self)
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Constraint programming is a technology which is now widely used to solve combinatorial problems in industrial applications. However, using it requires considerable knowledge and expertise in the field of constraint reasoning.
Generating College Conference Basketball Schedules by a SAT Solver
 In Proceedings of the Fifth International Symposium on the Theory and Applications of Satisfiability Testing
, 2003
"... this paper, we will show how to produce a fair schedule with the assistance of a propositional solver, when we formulate the problem smartly ..."
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Cited by 11 (1 self)
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this paper, we will show how to produce a fair schedule with the assistance of a propositional solver, when we formulate the problem smartly
The Complexity of Reasoning with Global Constraints
 Constraints
, 2006
"... Constraint propagation is one of the techniques central to the success of constraint programming. To reduce search, fast algorithms associated with each constraint prune the domains of variables. With global (or nonbinary) constraints, the cost of such propagation may be much greater than the quad ..."
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Cited by 11 (1 self)
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Constraint propagation is one of the techniques central to the success of constraint programming. To reduce search, fast algorithms associated with each constraint prune the domains of variables. With global (or nonbinary) constraints, the cost of such propagation may be much greater than the quadratic cost for binary constraints. We therefore study the computational complexity of reasoning with global constraints. We first characterise a number of important questions related to constraint propagation. We show that such questions are intractable in general, and identify dependencies between the tractability and intractability of the different questions. We then demonstrate how the tools of computational complexity can be used in the design and analysis of specific global constraints. In particular, we illustrate how computational complexity can be used to determine when a lesser level of local consistency should be enforced, when constraints can be safely generalized, when decomposing constraints will reduce the amount of pruning, and when combining constraints is tractable.