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18
Constraint Solving in Uncertain and Dynamic Environments: A Survey
 Constraints
, 2005
"... Abstract. This article follows a tutorial, given by the authors on dynamic constraint solving at CP 2003 [87]. It aims at offering an overview of the main approaches and techniques that have been proposed in the domain of constraint satisfaction to deal with uncertain and dynamic environments. Keywo ..."
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Cited by 36 (3 self)
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Abstract. This article follows a tutorial, given by the authors on dynamic constraint solving at CP 2003 [87]. It aims at offering an overview of the main approaches and techniques that have been proposed in the domain of constraint satisfaction to deal with uncertain and dynamic environments. Keywords: constraint satisfaction problem, uncertainty, change, stability, robustness, flexibility
Uncertainty and change
 Handbook of Constraint Programming, chapter 21
, 2006
"... Constraint Programming (CP) has proven to be a very successful technique for reasoning about assignment problems, as evidenced by the many applications described elsewhere in this book. Much of its success is due to the simple and elegant underlying formulation: describe the world in terms of decisi ..."
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Cited by 30 (4 self)
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Constraint Programming (CP) has proven to be a very successful technique for reasoning about assignment problems, as evidenced by the many applications described elsewhere in this book. Much of its success is due to the simple and elegant underlying formulation: describe the world in terms of decision variables that must be assigned values, place clear and explicit restrictions on the values that may be assigned simultaneously, and then find a set of assignments to all the variables that obeys those restrictions. Thus, CP makes two assumptions about the problems it tackles: 1. There is no uncertainty in the problem definition: each problem has a crisp and complete description. 2. Problems are not dynamic: they do not change between the initial description and the final execution of the solution. Unfortunately, these two assumptions do not hold for many practical and important applications. For example, scheduling production in a factory is, in practice, fundamentally dynamic and uncertain: the full set of jobs to be scheduled is not known in advance, and continues to grow as existing jobs are being completed; machines break down; raw material
Towards declarative diagnosis of constraint programs over finite domains
 FIFTH INTERNATIONAL WORKSHOP ON AUTOMATED DEBUGGING, AADEBUG2003, GHENT: BELGIUM
, 2003
"... The paper proposes a theoretical approach of the debugging of constraint programs based on a notion of explanation tree. The proposed approach is an attempt to adapt algorithmic debugging to constraint programming. In this theoretical framework for domain reduction, explanations are proof trees expl ..."
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Cited by 7 (1 self)
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The paper proposes a theoretical approach of the debugging of constraint programs based on a notion of explanation tree. The proposed approach is an attempt to adapt algorithmic debugging to constraint programming. In this theoretical framework for domain reduction, explanations are proof trees explaining value removals. These proof trees are defined by inductive definitions which express the removals of values as consequence of other value removals. Explanations may be considered as the essence of constraint programming. They are a declarative view of the computation trace. The diagnosis consists in locating an error in an explanation rooted by a symptom.
Theoretical Foundations of Value Withdrawal Explanations for Domain Reduction
 11TH INTERNATIONAL WORKSHOP ON FUNCTIONAL AND (CONSTRAINT) LOGIC PROGRAMMING, GRADO: ITALY
, 2002
"... Solvers on finite domains use local consistency notions to remove values from the domains. This paper defines value withdrawal explanations. Domain reduction is formalized with chaotic iterations of monotonic operators. To each operator is associated its dual which will be described by a set of rule ..."
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Cited by 6 (4 self)
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Solvers on finite domains use local consistency notions to remove values from the domains. This paper defines value withdrawal explanations. Domain reduction is formalized with chaotic iterations of monotonic operators. To each operator is associated its dual which will be described by a set of rules. For classical consistency notions, there exists a natural such system of rules. They express value removals as consequences of other value removals. The linking of these rules inductively defines proof trees. Such a proof tree clearly explains the removal of a value (the root of the tree). Explanations can be considered as the essence of domain reduction.
Automata for nogood recording in constraint satisfaction problems
 In CP06 Workshop on the Integration of SAT and CP techniques
, 2006
"... Abstract. Nogood recording is a well known technique for reducing the thrashing encountered by tree search algorithms. One of the most significant disadvantages of nogood recording has been its prohibitive space complexity. In this paper we attempt to mitigate this by using an automaton to compactly ..."
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Abstract. Nogood recording is a well known technique for reducing the thrashing encountered by tree search algorithms. One of the most significant disadvantages of nogood recording has been its prohibitive space complexity. In this paper we attempt to mitigate this by using an automaton to compactly represent a set of nogoods. We demonstrate how nogoods can be propagated using a known algorithm for achieving generalised arc consistency. Our experimental results on a number of benchmark problems demonstrate the utility of our approach. 1
Stable solutions for dynamic project scheduling problems
"... programming and scheduling The Resource Constrained Project Scheduling Problem (rcpsp) is a general scheduling problem which consists in scheduling a set of activities taking into account temporal and resource constraints (Demeulemeester and Herroelen, 2002). Preemption is not allowed. The objective ..."
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Cited by 1 (0 self)
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programming and scheduling The Resource Constrained Project Scheduling Problem (rcpsp) is a general scheduling problem which consists in scheduling a set of activities taking into account temporal and resource constraints (Demeulemeester and Herroelen, 2002). Preemption is not allowed. The objective considered here is the minimization of the makespan (total duration) of the project. This problem is NPhard (Blazewicz et al., 1983). Most work about rcpsp consider static problems in which activities are known in advance and constraints are fixed. However, every schedule is subject to unexpected events (consider for example a new activity to schedule, or a resource failure – eg. machine breakdown). When such a situation arises, a new solution taking these events into account is needed generally in a short time. Furthermore, this new solution must preferably be not too far from the previous one. Several works concern dynamic scheduling problems. But generally, they deal with very specific problems like onemachine problems (Mehta et Uzsoy, 1999;,
2004, ‘Constraint Processing with Reactive Agents
 In: 17th International FLAIRS Conference
"... The integration of methods of Constraint Programming and MultiAgentSystems is discussed in this paper. We describe different agent topologies for Constraint Satisfaction Problems and discuss their properties with a special focus on dynamic and distributed settings. This motivates our new architect ..."
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The integration of methods of Constraint Programming and MultiAgentSystems is discussed in this paper. We describe different agent topologies for Constraint Satisfaction Problems and discuss their properties with a special focus on dynamic and distributed settings. This motivates our new architecture for constraint processing with reactive agents. The resulting systems are very flexible and can be used to process dynamic and distributed problems. We define the local behaviors of the agents in this new approach and verify their collective behavior in the context of CSP.
Interactively Solving School Timetabling Problems Using Extensions of Constraint Programming
 PATAT 2004 — Proceedings of the 5th International Conference on the Practice and Theory of Automated Timetabling
, 2004
"... Timetabling problems have been frequently studied due to their wide range of applications. However, they are often solved manually because of the lack of appropriate computer tools. Although many approaches mainly based on local search or constraint programming seem to have been quite successful ..."
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Timetabling problems have been frequently studied due to their wide range of applications. However, they are often solved manually because of the lack of appropriate computer tools. Although many approaches mainly based on local search or constraint programming seem to have been quite successful in recent years, they are often highly dedicated to specific problems and encounter di#culties to take the dynamic and overconstrained nature of such problems.
Constraint Processing with Reactive Agents
"... The integration of methods of Constraint Programming and MultiAgentSystems is discussed in this paper. We describe different agent topologies for Constraint Satisfaction Problems and discuss their properties with a special focus on dynamic and distributed settings. This motivates our new archi ..."
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The integration of methods of Constraint Programming and MultiAgentSystems is discussed in this paper. We describe different agent topologies for Constraint Satisfaction Problems and discuss their properties with a special focus on dynamic and distributed settings. This motivates our new architecture for constraint processing with reactive agents. The resulting systems are very flexible and can be used to process dynamic and distributed problems. We define the local behaviors of the agents in this new approach and verify their collective behavior in the context of CSP.
unknown title
, 2008
"... Abstract. Timetabling problems have been frequently studied due to their wide range of applications. However, they are often solved manually because of the lack of appropriate computer tools. Although many approaches mainly based on local search or constraint programming seem to have been quite succ ..."
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Abstract. Timetabling problems have been frequently studied due to their wide range of applications. However, they are often solved manually because of the lack of appropriate computer tools. Although many approaches mainly based on local search or constraint programming seem to have been quite successful in recent years, they are often highly dedicated to specific problems and encounter difficulties to take the dynamic and overconstrained nature of such problems. We were confronted with such an overconstrained and dynamic problem in our institution. This paper deals with a timetabling system based on constraint programming with the use of explanations to offer a dynamic behaviour and to allow automatic relaxations of constraints. Our tool has successfully answered the needs of the current planner by providing solutions in a few minutes instead of a week of manual design. We present in this paper the techniques used, the results obtained and a discussion on the effects of the automation of the timetabling process. 1