OCNs stands for optimal channel networks. They are topological configurations of channels that minimize energy expenditure and reproduce the statistical features of real river networks. They were the main topic of my Ph. Thesis, and go some influence in understanding why in nature, many structures are networks, and two of my most cited papers cover this topic. Eventually my advisors and co-workers pursue further the studies and pushed forward the research.
In figures above (top) a small random network developed according to an Eden growth procedure which start from the outlets (seeds of the growth), and (bottom) a OCN developed from it.
Recently I was asked to go back to the topic and do some simulation. For the task, I decided to abandon the old version of the program (first programmed in Mathematica, and secondly in C) and to build a new one in Java. The new version is part of the Java for Hydrologists (and geoscientists) 101 and can be found at github under the project Geoframe (package OCNs). News will follow.
Worth to say, other groups of people are working on OCNs. Notably Lily Briggs and her advisor, prof. Mukkai Krishnamoorthy, are also working on OCNs. She built three-dimensional OCNs. Her paper is here and her code is here, in Github.