An evaporative approach to handle dynamics in diffusive aggregation schemes

Distributed computing in large-size dynamic networks often requires the availability at each and every node globally aggregated information about some overall properties of the network. In this context, since traditional broadcasting solutions become inadequate as the number of participating nodes increases, aggregation schemes inspired by the physical/biological phenomenon of diffusion have been recently proposed as a simple yet effective alternative to solve the problem. However, diffusive aggregation requires specific solutions to cope with the dynamics of the network and/or of the values being aggregated. While typical solutions are based on periodic restarts (epoch-based approaches), in this paper, we propose an original and more autonomic solution, relying on coupling diffusive aggregation schemes with the additional bio-inspired mechanism of evaporation. While a gossip-based diffusive communication scheme is used to aggregate values over a network, gradual evaporation of values can be exploited to account for network and value dynamics without requiring periodic restarts. A comparative performance evaluation shows that the evaporative approach is able to manage the dynamism of the values sensed over the network in an effective way and, in the most of the cases, it leads to more accurate aggregate estimations than epoch based techniques.