"array" (was visual encoding)

[Martin Taylor 2000.02.19.13:14]

[From Bruce Nevin (2000.02.18.1155 EST)]

I know that you have been looking for ways to talk about cross-connections
between elementary control systems. Does the notion of arrays help you with
that? If so, can you explain how it helps?

The mathematical notion of "array" hasn't entered the discussion
except in your message.

I'm concerned not with explicit cross connections, but with what
happens, specifically in respect of reorganization, in an environment
in which the actions of one control unit may affect the ability of
another to control. In other words, I'm concerned with the
interactions among control units. I haven't brought this subject up
explicitly on CSGnet, but I have been thinking about it (and I gave a
talk on it at the CSG meeting in Durango 93). Regardless of my
specific interest, we _do_ need a language in which we can talk about
what happens among large numbers/arrays/groups/sets of control
systems that can affect each other.

There are several different kinds of interaction between two control
units. Here's a partial list, in which A is always the prime actor:

(1) A is not influenced by B but:
   (1a) The side effects of A's control actions disturb B's perceptual signal
   (1b) A controls a CEV that is not orthogonal to B's CEV (i.e. the
_deliberate_ effects of A's control actions disturb B's perceptual
signal.)
   (1c) The side effects of A's control actions affect the linkage
between the disturbance source and B's CEV.
   (1d) The deliberate effects of A's control actions affect the
linkage between the disturbance source and B's CEV. [Note: in 1c and
1d, the effect could be either to strengthen the disturbing influence
on B or to shield B from the disturbance. I'm particularly interested
in how reorganization might proceed when the effect is shielding.]
   (1e (and f)) The side effects (deliberate effects) of A's control
actions affect B's environmental feedback path, thereby changing the
characteristics of B's control loop.

(2) A is influenced by B's actions through A's perceptual input (B
disturbs A's perception). There are 6 cases here, matching 1a-1d.

(3, included so it is clear this case is not ignored) A and B are
hierarchically related:
   (3a) A's perceptual signal forms a part of B's perceptual input.
   (3b) B's output signal forms part of A's reference input.
In these case, it is assumed that 3a and 3b are mutually exclusive.

And indeed, there could also be the situation you were
considering--cross connections between elementary control units,
though that possibility does not occur in the canonical hierarchy
that we were talking about. There are several different cases here,
none of which are of immediate interest in the present context
(though you are right that the case "A's perceptual signal forms part
of B's perceptual input while B's perceptual signal forms part of A's
perceptual input" is the flip-flop connection I have discussed).

How does the notion of arrays help in the discussion? It helps only
if it helps clarify the discussions with people competent to deal
with the issues of how large numbers/sets/arrays/groups of control
units interact, and how those interactions evolve over long periods
of reorganization. Particularly, it might be of help if it clarifies
a discussion of the evolution of "language as an artifact", which was
the subject of my talk in Durango 93.

Martin