Given a hexagonal mesh of base stations in cellular systems we consider the problem of nding a cover of disjoint clusters of base stations which generate multiple types of traac among themselves. The problem diiers from general graph partitioning problems in that it considers not only communication costs but also the underlying topology among base stations, such that base stations in a cluster ...

information shoring among databases, scientific or business, requires the development of techniques for accessing data porn multiple heterogeneous databases. Orie approach to providing interoperability among these databases, is to de$ne one or more federated schemas which represent a coherent view of the underlying databases. A review of existing research on schema integration, the process of g...

Hyperheuristics can be defined to be heuristics which choose between heuristics in order to solve a given optimisation problem. The main motivation behind the development of such approaches is the goal of developing automated scheduling methods which are not restricted to one problem. In this paper we report the investigation of a hyperheuristic approach and evaluate it on various instances of ...

The vertex coloring problem is a classical problem in combinatorial optimization that consists of assigning a color to each vertex of a graph such that no adjacent vertices share the same color, minimizing the number of colors used. Despite the various practical applications that exist for this problem, its NP-hardness still represents a computational challenge. Some of the best computational r...

In wireless sensor networks, the main obstacle is power limitation and memory constraint. As communication is the most power consuming task, we need to minimize both the number of communications and concise the amount of data.To achieve these goals, previous works proposed different techniques like query optimization using various heuristics ,in-network data aggregation, efficient routing , ext...

We describe a parallel linear programming and implication based heuristic for solving set partitioning problems on distributed memory computer architectures Our implementation is carefully designed to exploit parallelism to greatest advantage in advanced techniques like preprocessing and probing primal heuristics and cut generation A primal dual subproblem simplex method is used for solving the...

This paper documents our investigation into various heuristic methods to solve the vehicle routing problem with time windows (VRPTW) to near optimal solutions. The objective of the VRPTW is to serve a number of customers within prede®ned time windows at minimum cost (in terms of distance travelled), without violating the capacity and total trip time constraints for each vehicle. Combinatorial o...

The field of statistical disclosure control aims to reduce the risk re-identifying an individual from disseminated data, a major concern among national agencies. Operations Research (OR) techniques have been widely used in past for protecting tabular but not microdata (i.e., files individuals and attributes). Few papers apply OR microaggregation problem, which is considered one best methods pro...

Automated planning is the process of automatically selecting actions that achieve a desired outcome. This paper summarises several contributions that improve the e ciency of automated planning via heuristic search. We discuss novel heuristics based on landmarks and a search algorithm for anytime planning. Furthermore, we analyse various searchenhancement techniques and show how the combination ...

It has been shown that evolutionary algorithms enriched with heuristics are capable of finding promising solutions for dynamic optimization problems. The utilization of hyperheuristics for the maintenance of cooperation among such heuristics is an interesting topic. In this study, hypermutation, random initialization and using a diploid representation are chosen as the three basic techniques th...