Retrofaction, Testing theories, Quality of Control -Reply

[Hans Blom, 960130f]

(Rick Marken (960129.1100))

There is no absolute for the quality of control.

You're right about the measure of control of temperature being
dependant on the scale of measurement ... But there are other
measures of control that are absolute. One is the stability measure

S = 1- (V/V')^1/2

where V is actual and V' expected variance of the controlled
variable. ... but its not a great general-purpose measure of

.control.

I think that, in practice, we are stuck with relative measures of
control; ie. RMS error, ratio of reference to actual values of
controlled variables, etc. But that's OK.

Agreed. As long as we compare. Controller versus controller, where
both live in the same world. Control of one controller in one world
versus it controlling in another world. Control with one parameter
setting versus control with a different parameter setting.

Greetings,

Hans

[Hans Blom, 960130e]

(Rick Marken (960129.1100))

If the outside world (partly) determines reference levels, it -- by
implication -- controls what the organism controls for. Agreed thus
far?

No. The outside world _determines_ reference levels but it doesn't
_control_ them.

Let's take small steps now. I rephrase the above: If the outside
world (partly) determines reference levels, it -- by implication --
(partly) determines what the organism controls for. Agreed thus far?

Hans