Solving problems is perhaps the most common and important human activity. Increasing complexity in social, technical or economical systems emphasizes the limits of traditional techniques for solving problems. These techniques proved to be inadequate for addressing complex real-world problems. Complexity generates computational intractable problems (within the exact solution paradigm).
Nature became a great inspiration source of models and techniques for problem solving. Nature-inspired techniques have been designed and applied for solving several large-scale optimization and search problems.