AGENT-BASED MODELLING FOR SYSTEMS BIOLOGY

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Complex Systems

Although it is difficult to give a formal characterisation of complex systems, the following characteristics are generally agreed to be present (Cilliers, 1998):

  • Complex systems consist of a large number of elements.

  • The elements of a complex system interact in a dynamic fashion and these interactions change over time.

  • The interactions between elements are richly connected - any one element influences, and is influenced by, a large number of others.

  • The interactions between elements are nonlinear. Small causes have large results, and vice versa.

  • The interactions between elements are relatively short-range. Physical constraints and information are mostly transmitted between immediate neighbours. However, this does not mean that there cannot be long-range influences. These can also be enhanced, suppressed, or modulated in some way along their path.

  • There are recurrent interaction pathways. The effects of a state change at one element can feed back on itself, either directly or via a number of intervening states.

  • Complex systems have a history. They evolve through time, and their present state is constrained by their past.

References:

Cilliers, P. Complexity and Postmodernism. Routledge, London, 1998.

 

© 2006 Chih-Chun Chen, Christopher D. Clack, Sylvia Nagl