Self-Organization: A Common Principle of Information Processing by Distributed Dynamic Systems - Molecular Computing: Origins and Promises - page 180

In view of all this opposition between the concept of “self-organization” and a
number of concepts such as self-assembly, dissipation, and conservative self-
organization, this hardly makes sense. These concepts, of course, can be used as
limited terms highlighting some partial aspect of the phenomenon. In general, all of
them rather correspond to separate levels of the general concept of “self-organiza-
tion,” which differ in complexity (structural and behavioral), corresponding to the
considered level of the process and its dynamic mechanism.

6.4 Reaction-Diffusion Processor: A Self-Organizing
Dynamic System

Self-organization plays a decisive role in information processing by biological
objects at different levels of their complexity. Therefore, devices that implement
biological principles of information processing fundamentally differ in terms of
their physical nature from von Neumann devices commonly used today.
Consider as an example a possible variant of the processor based on the
Belousov-Zhabotinsky chemical reaction-diffusion medium. Without discussing
specific technical solutions, we will pay attention to the basic organizational
principles and mechanisms of functioning of the processor. We will use the specific
experience gained in the pilot study of the information capabilities of the prototypes
of such devices described in Chap. 5 .
Let us define the primary characteristics of the processor, which determine its
information capabilities. The processor must be an extended reaction-diffusion
medium, in the simplest case quasi two-dimensional, i.e., a layer whose thickness
is medium, small compared with its length and width. Dynamic regimes of the
reaction-diffusion medium are determined by its state—the chemical composition
and temperature. Therefore, the environment must be thermostated. The preserva-
tion of its initial composition in each regime must also be ensured, because the
components of the medium in a closed volume are depleted during the reaction.
One of the easiest ways to meet this condition is the use of a flow reactor, in which
the composition of the medium is continuously kept constant. Let us also assume
that the Belousov-Zhabotinsky medium is light sensitive. Therefore, the illumina-
tion of the environment should be strictly regulated. Assume that the initial state of
the processor is given by a certain choice of concentrations of the medium compo-
nents. It will be shown below that it is most convenient to choose this state such that
the concentration of medium components would correspond to the vibrational mode
at zero illumination of the medium (Fig. 6.11 ). We will assume that the catalyst of
the reaction is situated in the reactor and is immobilized on a suitable carrier. Under
these conditions, the medium, whose components are evenly distributed in the
system feeding the reactor, upon entering the reactor spontaneously goes over
into a dynamic state of concentration fluctuations. Thus, the initial working