Immune memory and gene library evolution in the dynamic clonal selection algorithm

This paper describes two extensions to the original DynamiCS: (1) the deletion of memory detectors that are no longer valid and (2) the simulation of gene library evolution. Firstly, DynamiCS is extended in order to decrease the false positive (FP) error rates caused by memory detectors. The extended DynamiCS eliminates memory detectors when they show a poor degree of self-tolerance to new antigens. This system is tested to determine whether surviving memory detectors no longer cause high FP error rates. The results show a marked decrease in FP errors produced by the system but an increase in the amount of costimulation required. The large amount of costimulation can render the system weak for intrusion detection. The second extension to DynamiCS is proposed to resolve this problem. It employs the use of hypermutation to produce the effect of gene library evolution. This is designed to fine-tune generated memory detectors so that the system obtains higher true positive (TP) detection rates without increasing the amount of co-stimulation. The new extension is tested to determine whether it gains high TP detection rates without increasing the amount of costimulation as the result of gene library evolution. The test results prove that hypermutation leads the progress of gene library evolution and thus produces immature detectors that are more tuned to cover existing non-self antigens.