On self-adaptation in systems-of-systems

Adaptivity and systems-of-systems (SoS) have always had a close relationship, as it is one of their defining features. Moreover, there is a clear similarity between the requirements of a SoS and those of many adaptive systems, such as autonomic and self-adaptive systems. In recent years, this kind of adaptive systems has been carefully studied; however, they often operate at a very different scale, being smaller than a typical SoS. The common nexus between both perspectives seem to be situated at the architectural level: the same adaptive techniques are recursively applied in different strata in a hierarchical composite. Therefore, the principles embodied in adaptive architectures seem to provide a good basis for the definition and description of SoS. This paper relates those principles to the corresponding structures in software evolution, and suggests to coordinate both through a pace layering strategy.