2) Clonal Selection Model
The Clonal selection algorithm is based on the natural B-cell mechanism [9]. Immature B-cells circulate in the blood and the lymphatic organs. Once the receptors of such a B-cell match to an antigen they propagate and change in order to achieve a better matching. Those B-cells with better matching propagate again; this process repeats and produces the best matching B-cells. This process is shown in the figure1. In the literature De Castro presents an algorithm, called CLONALG [12], which is based on this natural clonal selection.