[From Bjorn Simonsen (2006.05.23,21:25EUST)]
[Martin Taylor 2006.05.21.09.53]
[From Bjorn Simonsen 2006.05.21,13:10 EUST)]
I think all conflicts result in oscillations. If there is no oscillation,
there is no conflict.
They don’t when you model them in simulations. To get oscillations in
any system, you need special condition involving time delays. When
you do get oscillations, there must be nonlinearities in the system,
or the result is literally an explosion (which is, I guess, an
expression of a nonlinearity :-).
Let me start again.
Rick expressed the development of a conflict below.
From Rick Marken (2006.05.19.0900)
The conflict explanation of bulimia (binge eating and then purging) is
that it is a conflict in oscillation. What is oscillating is the output
in conflict ( eating in this case). This oscillation shows up as swings
in the output in favor of one goal (eating to produce satiation) and
then the other (purging, which is like negative eating, to produce
thinness).
On your figure in your mail “Martin Taylor 2006.05.22.17.09”, the two outputs are o1 and o2.
Let me also refer to Tim A. Carey page 54, last section:
“Patric seemed to be very aware of a struggle as he oscillated between selling now and selling later”. Selling now and selling later are the two outputs o1 and o2 on your figure.
I remember from the day after I first time met my wife. I oscillated between going to the phone to invite her for a movie show and not going to the phone because I would not be answered that she was occupied with other things. I went to the phone and I left the phone. I lifted the phone and I placed the phone back. I oscillated between phoning and not phoning, the two outputs o1 and o2 on your figure. I don’t exploded. Where is the nonlinearity?
I will take it as an advise an listen to your “You don’t study oscillations in connexion with conflict”. But at first I thought that was a good idea to look upon conflicts as oscillations (not always). In what connexions is it rational to study oscillations?
Martin Taylor 2006.05.21.09.53
From Bjorn Simonsen 2006.05.21,13:10 EUST)
I think all conflicts result in oscillations. If there is no oscillation,
there is no conflict.
They don’t when you model them in simulations. To get oscillations in
any system, you need special condition involving time delays. When
you do get oscillations, there must be nonlinearities in the system,
or the result is literally an explosion (which is, I guess, an
expression of a nonlinearity :-).
I see the involving of time delays, and I understand it as if one system must be delayed when the first system is operating. Or is that wrong. I see the possibility for explosion if different parameters are nonlinear. I see it on Ricks conflict file. There the explosion comes with the gain and if the reference is not constant. Are there other parameters that lead to the explosion?
Let me now comment you (our) “Martin Taylor 2006.05.22.17.09”
me:
When I perceive and experience this, a copy of the
perceptual signal goes to a conflicted goal. I get a
great error and I perceive what I wish in the
conflicted system. This perceptual signal goes to
the first goal and I get a great error etc. This is
what I say is oscillating.
Martin:
I’m afraid I can’t follow what you are saying. What
is “a copy of the perceptual signal” that “goes to a
conflicted goal”? How do you “perceive what you
sish in the conflicted system?” There are at least two
conflicted systems. What does it mean to say that a
perceptual signal goes to a goal?
I think your figure is OK, very OK. But I use an equivalent figure at three levels. One low level where the output goes to muscles and glands. This is the level where the environmental disturbance is sensed. This system work for itself. The perceptual signal goes to the comparator etc. A copy of this perceptual signal goes to a middle level where two conflicting systems receive the perceptual signal. The one system controls for phoning and the other system controls for not phoning. This “copy” of perceptual signal goes to the comparator in both systems (look at your figure), but a copy of this perceptual signal goes to some or many systems at a level still above. These systems distribute their outputs to the two lower goals as references (phoning and not phoning). In this way two systems get different reference.
Let me go back to your mail.
The basic state of conflict occurs when several
control systems are trying to control their
perceptions but don’t have enough degrees of
freedom to work with. Not having enough degrees
of freedom means that they can’t all bring their
perceptions to their reference values at the same
time. The prototypical situation that is often simply
called “conflict” occurs when two control systems
try to control through paths that at some point
converge into a single degree of freedom.
This is OK. I understand what you say. I find it some different from one of the ways Bill explain conflict. I think he says that the two outputs, they are about equal and solidly over their maximum, will cancel. No net output will affect possible disturbances. The error will continue.
You say the two systems change their structure in a way to one system and one a changing controlled quantity (the red curve). This explains oscillation with a subsequent explosion.
The explosion comes because:
p1 = p1(v) = p1(o1+d1) = p1(g1(e1) + d1) = p1(g1(r1-p1) + d1)
p2 = p2(v) = p(o2+d2) …
where (v) is the same environmental variable
for both control systems. That’s the one degree
of freedom bottleneck in this example. System
1 “wants” p1 to equal r1, while system 2 wants
p2 to equal r2, and both depend on the single
value of v to make it happen.
Good written. I think I understand.
However, d1 is composed of two parts: d1 = o2 + d.env
and d2 = o1 + d.env. Either way, v = o1 + o2 + d.env.
where d.env is whatever external disturbance might affect d.
So, when system 1 tries to influence p1, it disturbs p2, and
vice versa. Each adjusts its output to counter the new
disturbance, creating a loop of influences that passes
through BOTH control systems (red, in the figure).
Rewriting the equation for control system 1,
p1 = p1(v) = p1(o1+o2+d.env) = p1(g1(e1)+g2(e2)+d.env) …
If oscillation is going to occur in this conflict, it will be in
this “extra” long (red) loop. Whether that happens or not
depends on the gains and timing constraints within the long
loop.
I think this is OK.
However, if there isn’t any nonlinearity, and the
system oscillates, the oscillation will explode to infinity.
Here it stops. Shall the nonlinearity lead to the red curve where two systems are working alternating?
More normally, the variable v will settle to some value
determined by the gains of the two systems, between
the values that the two systems individually would set
(which is what Kent showed). The other option in the
absence of nonlinearity is that the value of v will simply
go exponentially to infinity.
Where do I find what Kent show? If the are the figures on CSG-web, I can’t see any graphs.
bjorn
