Direct versus stigmergic information flow in systems-of-systems

The information flow among the Constituent Systems of a System-of-Systems can take place via two different channels: the message transport along communication channels in cyber space which includes the human-to-human communication in natural language among the humans that are part of the Constituent Systems, and the indirect information flow via sensors and actuators to the physical environment, called the stigmergic information flow. In many cases the stigmergic information flow forms an important link for the closure of control loops that can lead to emergent behavior. This paper elaborates the concepts of stigmergy and compares the characteristics of the stigmergic information flow versus the message based information flow in a System-of-Systems.