An immune system based differential evolution algorithm using near-neighbor effect in dynamic environments

Many real-world problems are dynamic, requiring optimization algorithms being able to continuously track changing optima (optimum) over time. This paper proposes an improved differential evolutionary algorithm using the notion of the near-neighbor effect to determine one individuals neighborhoods, for tracking multiple optima in the dynamic environment. A new mutation strategy using the near-neighbor effect is also presented. It creates individuals by utilizing the stored memory point in its neighborhood, and utilizing the differential vector produced by the 'nearneighbor-superior' and 'near-neighbor-inferior'. Taking inspirations from the biological immune system, an immune system based scheme is presented for rapidly detecting and responding to the environmental changes. In addition, a difference-related multidirectional amplification scheme is presented to integrate valuable information from different dimensions for effectively and rapidly finding the promising optimum in the search space. Experiments on dynamic scenarios created by the typical dynamic test instance-moving peak problem, have demonstrated that the near-neighbor and immune system based differential evolution algorithm (NIDE) is effective in dealing with dynamic optimization functions. © 2012 South China University of Technology, Academy of Mathematics and Systems Science, Chinese Academy of Sciences and Springer-Verlag Berlin Heidelberg.