Worth Reading

David A. Forsyth et al., Computational Studies of Human Motion: Part1, Tracking and Motion Synthesis.
comment: a good book to review the works in this area.

See P108, this book gives an excellent example of a simple non-linear system dynamic demonstrating multi-model behavior .I managed to verify this model by the following MATLAB script:

X0=randn(10000,1);
k=100
epsilon=1e-3;
for ii=1:k
X0=X0+epsilon*sin(X0);
end
hist(X0);

As k is small (=100), the system is still uni-model.

k=10000, there's two models