This paperthe concept of chaotic attractor is used only as an example of a dynamic behavior that coulda#ect the search process, we summarize the main characteristics and refer to [13] for a detailedtheoretical analysis. Chaotic attractors are characterized by a "contraction of the areas", sothat trajectories starting with di#erent initial conditions will be compressed in a limited areaof the configuration space, and by a "sensitive dependence upon the initial conditions", so thatdi#erent...