Local Search James M. Crawford i2 Technologies 909 East Las Colinas Boulevard Irving, TX 75039 [email protected] Mukesh Dalal i2 Technologies 909 East Las Colinas Boulevard Irving, TX 75039 [email protected] Joachim P. Walser Programming Systems Lab Univ. des Saarlandes, Postfach 151150 66041 Saarbrücken, Germany

The Spatial Semantic Hierarchy (SSH) provides a robot-independent ontology and logical theory for building topological maps of large-scale environments online. Existing SSH implementations make very limited use of perceptual information and thus create many candidate maps. Metrical mapping implementations capture detailed knowledge about local small-scale space but do not handle large environme...

In this paper we describe the advantadges and disadvantages of local search and exact methods of solving NP-hard problems and see why combining the two approaches is highly desirable. We review some of the papers existent in the literature that create new algorithms from such combinations. In this paper we focus on local search approaches that are strengthened by the use of exact algorithms.

For efficiency reasons, neighbourhoods in local search are often shrunk by only considering moves modifying variables that actually contribute to the overall penalty. These are known as conflicting variables. We propose a new definition for measuring the conflict of a variable in a model and apply it to the set variables of models expressed in existential second-order logic extended with counti...

This work presents a local search approach to the High School Timetabling Problem. The addressed timetabling model is the one stated in the Third International Timetabling Competition (ITC 2011), which considered many instances from educational institutions around the world and attracted seventeen competitors. Our team, named GOAL (Group of Optimization and Algorithms), developed a solver built...

Using constraint-based local search, we effectively model and efficiently solve the problem of balancing the traffic demands on portions of the European airspace while ensuring that their capacity constraints are satisfied. The traffic demand of a portion of airspace is the hourly number of flights planned to enter it, and its capacity is the upper bound on this number under which air-traffic c...

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