Octagonal Domains for Continuous Constraints

International audienceDomains in Continuous Constraint Programming (CP) are generally represented with intervals whose $n$-ary Cartesian product (box) approximates the solution space. This paper proposes a new representation for continuous variable domains based on octagons. We generalize local consistency and split to this octagon representation, and we propose an octagonal-based branch and prune algorithm. Preliminary experimental results show promising performance improvements on several classical benchmarks

Intelligent Splitting for Disjunctive Numerical CSPs

International audienceDisjunctions in numerical CSPs appear in applications such as Design, Biology or Control. Generalized solving techniques have been proposed to handle these disjunctions in a Branch&Prune fashion. However, they focus essentially on the pruning operation. In this paper, we present experimental evidences that significant performance gains can be expected by exploiting the disjunctions in the branching operation

Reverse Blending: an efficient answer to the challenge of obtaining required fertilizer variety

Mass customization, a major trend in modern economy, relies on components assembly in discrete production, while in continuous production, it consists in a sequence of batches of different products. This limits achievable diversity and multiplies transportation issues. This situation is addressed by the fertilizer industry which, to enable sustainableagriculture, must deliver fertilizers tailored to soil and crops characteristics. We are now proposing a new approach to handle this situation, with a solution called reverse blending, which involves delayed differentiation performed near end-users. This consists in defining the components for a very limited number of inputs whose blend exactly matches the characteristic of the required fertilizers. In this solution, the problem is modelled by a quadratic program used to define input optimal composition, respect fertilizer components constraints and cater to any type of demand. Reverse blending may have a major impact on supply chain organization. A short case study of this new approach is provided

Franco-Japanese Research Collaboration on Constraint Programming

International audienceConstraint programming is an emergent technology that allows modeling and solving various problems in many areas such as artificial intelligence, computer programming, computer-aided design, computer graphics, and user interfaces. In this report, we provide recent activities of research collaboration on constraint programming conducted by the authors and other researchers in France and Japan. First, we outline our joint research projects on constraint programming, and then present the backgrounds, goals, and approaches of several research topics treated in the projects. Second, we describe the two Franco-Japanese Workshops on Constraint Programming (FJCP), which we organized in Japan in October 2004 and in France in November 2005. We conclude with future prospects for collaboration between French and Japanese researchers in this area

Un solveur de contraintes basé sur les domaines abstraits

International audienceDans cet article, nous utilisons des techniques de l'interpréation abstraite (une théorie d'approximation des sémantiques) dans le cadre de la programmation par contraintes (basée sur la logique du premier ordre qui permet de résoudre des problèmes combinatoires). Nous mettons en évidence certains liens et différences entre ces domaines de recherches : tous deux calculent itérativement des points fixes mais emploient des extrapolations et stratégies de raffinement différentes. De plus, nous pouvons mettre en correspondance les consistances en programmation par contraintes et les domaines abstraits non relationnels. Nous utilisons ensuite ces correspondances pour construire un solveur de contraintes abstrait qui s'appuie sur des techniques d'interprétation abstraite (comme les domaines relationnels) pour aller au-delà des solveurs classiques. Les résultats expérimentaux obtenus avec notre prototype sont encourageants

A Branch and Bound Algorithm for Numerical MaxCSP

Abstract. The Constraint Satisfaction Problem (CSP) framework allows users to define problems in a declarative way, quite independently from the solving process. However, when the problem is over-constrained, the answer "no solution" is generally unsatisfactory. A Max-CSP Pm = V, D, C is a triple defining a constraint problem whose solutions maximise constraint satisfaction. In this paper, we focus on numerical CSPs, which are defined on real variables represented as floating point intervals and which constraints are numerical relations defined in extension. Solving such a problem (i.e., exactly characterizing its solution set) is generally undecidable and thus consists in providing approximations. We propose a branch and bound algorithm that computes under and over approximations of its solution set and determines the maximum number mP of satisfied constraints. The technique is applied on three numeric applications and provides promising results

Le patrimoine culturel immatériel au seuil des sciences sociales

L’entrée en vigueur de la Convention sur la sauvegarde du patrimoine culturel immatériel (PCI) de 2003 a abouti, dès 2009, au dépôt des premières candidatures sur les listes de l’Unesco, alors même que le champ du PCI était encore peu connu des chercheurs et des acteurs du patrimoine. Après plusieurs années marquées par la prédominance des recherches ethnologiques sur ce nouveau patrimoine, le Centre culturel international de Cerisy-la-Salle (Normandie) accueillait du 24 au 29 septembre 2012 un colloque international rassemblant des chercheurs de plusieurs disciplines (ethnologues, anthropologues, économistes, juristes, historiens, géographes), des responsables de l’Unesco, des fonctionnaires de l’administration culturelle et des acteurs de terrain associatifs. Les participants y confrontaient pour la première fois des lectures contrastées de l’histoire du PCI, de la valeur politique de ce patrimoine et du rôle qu’y tient la participation des « communautés ». Nourrit de nombreuses études de cas empruntées au contexte international mais aussi au contexte territorial de la Normandie, ce colloque de Cerisy fut ainsi la première entreprise intellectuelle collective de grande ampleur consacrée au PCI où ont été énoncés les prémisses de recherches pluridisciplinaires promises aux développements que l’on constate aujourd’hui. Il a de ce fait constitué un tournant décisif dans les études patrimoniales liées à l’immatériel. Cet important volume réunit les actes de cette rencontre majeure qui a fait date dans l’histoire de la réflexion sur la mise en œuvre de la Convention Unesco