Document 
Eur. Phys. J. B 38, 147-162 (2004)
DOI: 10.1140/epjb/e2004-00110-5
Complex networks
Augmenting the framework for the study of complex systems
L.A.N. Amaral and J.M. OttinoDepartment of Chemical and Biological Engineering, Northwestern University, Evanston, IL 60208, USA amaral@northwestern.edu
(Received 12 November 2003 / Published online 14 May 2004 )
Abstract
We briefly describe the toolkit used for studying complex
systems: nonlinear dynamics, statistical physics, and network theory.
We place particular emphasis on network theory-the topic of this
special issue-and its importance in augmenting the framework for the
quantitative study of complex systems. In order to illustrate the
main issues, we briefly review several areas where network theory has
led to significant developments in our understanding of complex
systems. Specifically, we discuss changes, arising from network
theory, in our understanding of (i) the Internet and other
communication networks, (ii) the structure of natural ecosystems,
(iii) the spread of diseases and information, (iv) the structure
of cellular signalling networks, and (v) infrastructure robustness.
Finally, we discuss how complexity
requires both new tools and an augmentation of the conceptual
framework-including an expanded definition of what is meant by a
"quantitative prediction."
89.75.Fb - Structures and organization in complex systems.
89.75.Da - Systems obeying scaling laws.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2004