COMMUNICATION WITH CHEMICAL CHAOS IN THE PRESENCE OF NOISE

We use control of chaos to encode information into the oscillations of the Belousov-Zhabotinsky reaction. An arbitrary binary message is enc oded by forcing the chaotic oscillations to follow a specified traject ory. The information manipulating control requires only small perturba tions to vary the binary message. In this paper we extend our recent t heoretical work [Bollt and Dolnik, Phys. Rev. E 64, 1196 (1990)] by in troducing anew and simplified encoding technique which can be utilized in the presence of experimental noise. We numerically and theoretical ly study several practical aspects of controlling symbol dynamics incl uding: modeling noisy time-series, learning underlying symbol dynamics , and evaluation of derivatives for control by observing system respon ses to an intelligent and deliberate sequence of input parameter varia tions. All of the modeling techniques incorporated here are ultimately designed to learn and control symbol dynamics of experimental data kn own only as an observed time-series;the simulation assumes no global m odel. We find that noise affects reliability of encoding information a nd may cause coding errors. But, if the level of noise is confined to relatively small values, which are achievable in experiments, the cont rol mechanism is robust to the noise. Thus we can still produce a desi red symbolic code. However, scarce errors in encoding may occur due to rare but large fluctuations. These errors may be corrected during the decoding process by a variation of the filtering technique suggested by Rosa et al. (C) 1998 American Institute of Physics.