General measure of chaoticity of a system?

[Gerenuk]

Is there a way to have some observables, apply an equation and find a measure if the system is chaotic or not?

For example, measure the time-dependent displacement of the wings of an airplane, apply some analysis and then say "OMG! And I mean O.M.G.! We are in the chaotic regime. Better do something about it!"

 

[atyy]

According to these guys, it's easy to fool yourself, but they also give some practical advice:

http://arxiv.org/abs/chao-dyn/9807001

http://arxiv.org/abs/chao-dyn/9810005

http://www.mpipks-dresden.mpg.de/~tisean/