Phenotropic and stigmergic webs: the new reach of networks

This article proposes a conceptual extension of sensor–actuator networks, taking in all “things” that can be sensed by sensors, or acted upon by actuators, in various physical modalities. These things become nodes of a web, graph, or virtual network overlaid on the existing sensor–actuator networks that make up the “Internet of Things”. The paper explains how the broader concepts of phenotropics and stigmergy may account for the special kind of connections that these networks entail. Phenotropics refer to a model of communication between nodes by way of pattern recognition. Stigmergy refers to a model of self-organization that uses communication between entities by modifications of a shared physical environment. Phenotropic–stimergic webs “loop back” sensor–actuator networks by way of the physical world. Graph-based complexity models provide a means of analyzing the hybrid systems made up by these networks and the additional nodes attached to them in this way. The evolution toward such paradigms in the realm of network-to-environment interfaces draws upon a similar, long-standing evolution in the realm of human-to-information interfaces. The paper explores the consequences of these new networking paradigms on the architecture, management, and organization of networks. It also shows how these ideas can expand and enrich present-day applications of pervasive networking, by taking full advantage of the physical nature of the new end points of digital networks, and how they bear upon human interfaces to networked services, possibly opening up new territories for universal access.