from the If-it's-not-one-thing-it's-another dept.
Researchers examining complex systems, both biological and artificial, find interesting parallels between communities of organisms and the Internet in their tolerance for error — and in their high vulnerability to attack. Complex networks of nanotech devices may exhibit similar behaviors; this presents a design challenge for future MNT systems engineers, as well as today's information system engineers. The article appeared in Nature (sorry, no link, since access requires an active subscription).
If you have access to the printed journal, see "Error and attack tolerance of complex networks," by Reka Albert, Hawoong Jeong and Albert-Loszlo Barabosi, Nature, v406, pp 378 – 382.
(The full text of the abstract appears in the "Read More.")
Update: The full text of the Nature article, plus a commentary is available either online or as an Acrobat PDF file on the Nature web site. (Note: Full access may eventually be cut off, but this was current as of 31 August 2000.)
Error and attack tolerance of complex networks
Reka Albert, Hawoong Jeong and Albert-Loszlo Barabosi
Nature v406, pp 378 – 382 (2000)
Many complex systems display a surprising degree of tolerance against errors. For example, relatively simple organisms grow, persist and reproduce despite drastic pharmaceutical or environmental interventions, an error tolerance attributed to the robustness of the underlying metabolic network. Complex communication networks display a surprising degree of robustness: although key components regularly malfunction, local failures rarely lead to the loss of the global information-carrying ability of the network. The stability of these and other complex systems is often attributed to the redundant wiring of the functional web defined by the systems' components. Here we demonstrate that error tolerance is not shared by all redundant systems: it is displayed only by a class of inhomogeneously wired networks, called scale-free networks, which include the World-Wide Web, the Internet, social networks and cells. We find that such networks display an unexpected degree of robustness, the ability of their nodes to communicate being unaffected even by unrealistically high failure rates. However, error tolerance comes at a high price in that these networks are extremely vulnerable to attacks (that is, to the selection and removal of a few nodes that play a vital role in maintaining the network's connectivity). Such error tolerance and attack vulnerability are generic properties of communication networks.