Issues in Complexity and Emergence

Complex systems are ubiquitous in nature --- bacteria colonies, amoebas and social insects on the one hand, and chemical, fluid and solid-state systems on the  other hand --- all exhibit complex behavior. Some cite human organizations as yet another example of a complex system. In many of these systems, while the individual and its behavior appear simple to the outside observer, the  collective behavior of the entire system can often be quite complex. In physical systems complexity manifests itself in pattern formation --- convection in fluid systems or reaction-diffusion patterns in chemistry. Biological systems, especially social insects, offer a rich domain for studying self-organization and collective behavior --- trail formation in ants, hive building by bees and mound construction by termites are just few of the examples of complex behaviors. The apparent success of these organisms has inspired computer scientists and engineers to design algorithms and distributed problem-solving systems modeled after them. While some aspects of complex systems have been quantitatively understood, other proposed facts have been only observed in models. While the mathematical theory of some systems has been well established, it is not clear whether existing mathematics is sufficient for other systems, or some as yet undiscovered (or is it?) science of complexity is needed. In these seminar series we will try to find out what the right questions are, and attempt to separate hype from reality.

Schedule

Topics

Questions

• What are complex systems? What is complex behavior? What empirical evidence for it exists?
• pattern formation
• self-organization
• collective behavior
• ?
• What concepts from complexity made an impact?
• biology
• physics 
• engineering
• models
• Why are models and concepts of compex systems so controversial?
• Pattern formation in physics/chemistry is not controversial. Why?
• Can complex systems be useful for engineering in general and communication networks in particular?
• What math/theory/models exist for complex systems?
• Does the science of complexity exist? Do we need new science?

Reading list

• G. Nicolis and I. Prigogine, Self Organization in Nonequilibrium Systems (Wiley, New York, 1977)
• Cross and Hohenberg, Pattern formation outside of equilibrium, [VERY LARGE FILE] Reviews of Modern Physics 65 851--1112
• Swinney group (UTexas/Austin)
• Ahlers group (UCSB)

• Stuart Kauffman, The Origins of Order: Self-Organization and Selection in Evolution Copyright 1993 by Oxford University Press
• Gordon lab (Stanford): field studies of collective behavior and organization in ants
  
• Julia Parrish, & WH Hamner (eds.) 1997. Animal Groups in Three Dimensions. Cambridge University Press, New York. 378p, also collective motion of fish schools
  

• Eric Bonabeau, Marco Dorigo and Guy Theraulaz, Swarm Intelligence: From Natural to Artificial Systems, New York, NY: Oxford University Press, Santa Fe Institute Studies in the Sciences of Complexity 1999
• Maja Mataric group (USC): design of robot collectives
• Alcherio Martinoli group (Caltech): quantitative studies of collective behavior in robots
  

• SOC: P. Bak, C. Tang, and K. Wiesenfeld, Phys. Rev. Lett . 59, 381 (1987).
• HOT: Carlson, J. M. & Doyle, J. Highly optimized tolerance: a mechanism for power laws in designed systems. Physical Review E, 60, 1412 - 1427, (1999). 
• D. Sornette, Critical Phenomena in Natural Sciences: Chaos, Fractals, Self-organization and Disorder: Concepts and Tools, 432 pp., 87 figs., 4 tabs  (Springer Series in Synergetics, Heidelberg, 2000)
  

• Remo Badii and Antonio Politi, Complexity Hierarchical Structures and Scaling in Physics, Cambridge Nonlinear Science Series, vol. 6. Cambridge University Press, 1997 
• Santa Fe Institute Computational Mechanics group: J. Crutchfield and C. Shalizi

• Laughlin and Pines, The Theory of Everything , in the Jan 4, 2000 issue of  Proceedings of the National Academy of Sciences.