ABSTRACT

A natural order parameter is the entropy, proposed by Gibbs. In classical thermodynamics, the entropy is defined only for equilibrium states, and these states, when separated from external forcing parameters, approach an entropy maximum. In non-equilibrium processes, however, the entropy may fluctuate and have local minima. In order to measure the level of self-organization in certain systems, one can use the spectral entropy introduced by Powell and Percival. The spectral entropy is a convenient parameter for quantifying self-organization in time series or power-spectra data. In many complex systems, self-organizing behavior is observed. The spectral entropy gives a quantitative measure of the power spectra. A power spectra where the energy is concentrated in a few wave numbers implies higher information content and yields lower spectral entropy. One of the advantages of the spectral entropy is its relative ease of computation.