### ASA 124th Meeting New Orleans 1992 October

## 5pPA12. A study of the premonitions of chaos.

**P. G. Vaidya
**

**
Tim Doughty
**

**
Rong He
**

**
**
*Dept. of Mech. and Mater. Eng., Washington State Univ., Pullman, WA
99164-2920
*

*
*
There are two unrelated developments that form the basis for research. One
of these is the work by Weisenfeld [J. Stat. Phys. (1985)]. He showed that a
small amount of noise would have a profound effect on the output spectrum of a
nonlinear system undergoing bifurcations. These modifications thus serve as the
precursors of these bifurcations. The second is the development of the
trans-spectral coherence technique for the analysis of nonlinear signals,
developed by Vaidya and Anderson [J. Acoust. Soc. Am. 89, 2370--2378 (1991)].
This technique has been used to educe small signals out of noise and to show
inherent structure in chaos. These two ideas are put together to show that such
precursors of chaos could be detected, even earlier, using the trans-spectral
coherence technique. Such detection, would have a wide range of applications,
from cardiology to oceanography.