Hard and soft precedence constraints play a key role in many application domains. In telecommunications, one application is the configuration of call control feature subscriptions where the task is to sequence a set of user-selected features subject to a set of hard (catalogue) precedence constraints and a set of soft (user-selected) precedence constraints. When no such sequence exists, the task is to find an optimal relaxation by discarding some features or user precedences. For this purpose, we present the global constraint SOFTPREC. Enforcing Generalized Arc Consistency (GAC) on SOFTPREC is NPcomplete. Therefore, we approximate GAC based on domain pruning rules that follow from the semantics of SOFTPREC; this pruning is polynomial. Empirical results demonstrate that the search effort required by SOFTPREC is up to one order of magnitude less than the previously known best CP approach for the feature subscription problem. SOFTPREC is also applicable to other problem domains including minimum cutset problems for which initial experiments confirm the interest.
 
Biography:
I received my PhD in computer science from Universite Catholique de Louvain in 2006 for my work on solving constrained graph problems using global constraints based on the notion of dominators. Since January 2007, I work as a research scientist at the Cork Constraint Computation Centre, a world- leading research centre dedicated to large-scale complex optimisation. During the last two and a half years I have been working on the personalization of context-aware telecommunication services. This project is being funded by IRCSET-Embark Initiative and British Telecom. During my PhD studies I  was one the research assistants of MISURE, a project with the European aerospace industry whose goal was to develop a system capable of automatically managing the mission of an uninhabited air vehicle. I am an invited lecturer at Pontificia Universidad Javeriana (Colombia) and have been teaching assistant at both Universite Catholique de Louvain (Belgium) and at the University of Melbourne (Australia).
 
Web: http://4c.ucc.ie/~lquesada/  and  http://4c.ucc.ie/web/index.jsp