Software architecture of self-organizing systems-of-systems for the Internet-of-Things with SosADL

A challenging issue in the architectural design of Systems-of-Systems (SoS) for the Internet-of-Things (IoT) is how to architect an SoS in a way that the required behavior to fulfil the SoS mission will emerge. Indeed, on the one hand, at design-time, most often we do not know which are the concrete IoT systems that will become constituents of the SoS, these being predominantly identified at run-time; on the other hand, the correct architecture depends not only on the constituent systems but also, largely, on the operational environment where the SoS will be deployed. To address this challenge, this paper investigates the notion of self-organization, whose mechanism makes possible that the IoT constituent systems themselves create and maintain a valid architecture enabling the production of the required emergent behavior to fulfil the SoS mission. In particular, it describes how SosADL, a formal SoS Architecture Description Language (ADL), based on the novel π-Calculus for SoS, supports the architectural description of self-organizing SoSs for the IoT, upwardly causing SoS emergent behaviors at run-time.