AbstrAct This chapter presents a hybrid between a particle swarm optimization (PSO) approach and scatter search. The main motivation for developing this approach is to combine the high convergence rate of the PSO algorithm with a local search approach based on scatter search, in order to have the main advantages of these two types of techniques. We propose a new leader selection scheme for PSO,...

The Max-Cut problem consists of finding a partition of the nodes of a weighted graph into two subsets such that the sum of the weights between both sets is maximized. This is an NP-hard problem that can also be formulated as an integer quadratic program. Several solution methods have been developed since the 1970s and applied to a variety of fields, particularly in engineering and layout design...

Project scheduling has received a growing attention from researchers for the last decades in order to propose models and methods to tackle scheduling problems for real-size projects. In this paper, we consider the resource-constrained project scheduling problem (RCPSP), which consists in scheduling the activities in order to minimize the project duration in presence of precedence and resource c...

Many real life optimization problems are nonconvex and may have several local minima within their feasible region. Therefore, global search methods are needed. Metaheuristics are efficient global optimizers including a metastrategy that guides a heuristic search. Genetic algorithms, simulated annealing, tabu search and scatter search are the most well-know metaheuristics. In general, they do no...

This paper deals with the problem of inaccuracy of the solutions generated by metaheuristic approaches for bi-criteria {0,1}-knapsack problems. A hybrid approach which combines systematic and heuristic search is proposed to reduce that inaccuracy in the context of a scatter search method. The components of the method are used to determine regions in the decision space to be systematically searc...

Scatter search (SS) and path relinking (PR) are evolutionary methods that have been successfully applied to a wide range of hard optimization problems. The fundamental concepts and principles of the methods were first proposed in the 1970s and 1980s, and were based on formulations, dating back to the 1960s, for combining decision rules and problem constraints. The methods use strategies for sea...

The crew scheduling problem in the airline industry is extensively investigated in the operations research literature since efficient crew employment can drastically reduce operational costs of airline companies. Given the flight schedule of an airline company, crew scheduling is the process of assigning all necessary crew members in such a way that the airline is able to operate all its flight...

Path-relinking is major enhancement to heuristic search methods for solving combinatorial optimization problems, leading to significant improvements in both solution quality and running times. We review its fundamentals and implementation strategies, as well as advanced hybridizations with more elaborate metaheuristic schemes such as genetic algorithms and scatter search. Numerical examples are...