Mobile processes, mobile channels and complex dynamic systems

This paper explores a process-oriented approach to complex systems design, using massive fine-grained concurrency, mobile channels and mobile processes. The complex systems studied are self-organising, with emergent and evolving behaviours (apparent at the global level) arising from massive interactions between relatively simple components (that have only local knowledge). Classical ant foraging is used as a case study. Processes are used to represent space, environmental factors and the ants themselves. Ant processes (like all processes) only have knowledge of their internal state (looking for food, looking for their nest) and what they can glean from their local neighbourhood (by interacting with the processes making up that neighbourhood). The networks constructed are dynamic, changing as the ants move around and environmental factors are introduced and modified. The paper reports on two mechanisms for achieving this: channel mobility and process mobility. The language for implementation is occam-pi, which has the necessary concurrency mechanisms built in as fundamental primitives and whose semantics is rooted in the process algebras of CSP and the pi-calculus. Performance figures are given, including speedup curves for multicores, and some conclusions drawn.