HDTenEightyP/NetNews huggingface dataset:
Newsgroups: bit.listserv.csg-l
Date:         Fri, 24 Jul 1992 13:25:21 EDT
From:         mmt@BEN.DCIEM.DND.CA
Subject: Re: Energy, Entropy, Info
X-cc:         randall@dretor.dciem.dnd.ca

[Martin Taylor 920724 10:30]
(Bill Powers 920723.2130 and Allan Randall 920723.2100)
=============
(This mailing was sent to Bill Powers personally, by mistake.  It was intended
for CSG-L, so here it is.  Sorry, Bill)
=============

I'm not going to comment directly on these two postings on information, energy,
and entropy.  And I had intended to let Bill's original report pass by, as
well, though I sympathize with Allan's complaints about it.

Information theory is much more subtle than either Bill's or Allan's
postings would suggest.  I think it would help both of them to read at least
the first few pages of Nicolis' "Dynamics of Hierarchical Systems" (Springer
Verlag, 1986), where he derives explicitly the relation between thermodynamic
and informational entropy, and shows that the thermodynamic requirements on
entropy per bit are so small that they can be ignored in any current practical
application.

Information flow can never be determined uniquely, because it is represented
by a change in probability structure as seen by the observer identifying the
information.  That observer may be a party to the transaction, but need not
be.  Information is a perceptual construct, not a physical one.  We had a
long go-around on this last year, but if you go back to the archives and
re-read that discussion, you might find it clarified by referring to my
recent "mirror diagram" of PCT.

Later, perhaps, if I find time, I'll try to write something that can be
deposited in Bill Silvert's ftp system, with an abstract to the net.  But
please don't take either Bill's or Allan's assertions about what Shannon
said too seriously.  They may both be on the side of public received wisdom,
but we all know how likely that is to be correct, don't we?

I'm not trying to diminish discussion of information.  Just be aware that
the direction of both Bill's and Allan's postings is very like that of
S-R psychology, and is just as valid.

Martin
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Date:         Tue, 21 Jul 1992 12:29:08 CDT
From:         "Patricia Alfano" <upalfano@UXA.ECN.BGU.EDU>
Subject:      data analysis
X-To:         csg-l@vmd.cso.uiuc.edu

[From Pat Alfano]

July 21, 1992

I am not very happy with the data analysis I am doing on some recently
collected data.  I was wondering if PCT might offer me a new way of
looking at the data.

Briefly, I used two neuropsychological tests of spatial orientation and
had subjects perform them under different conditions.  Subjects were
timed and errors counted.  After the test subjects were given a list of
strategies and asked to check off any of the strategies they may have
used to perform the test, and to note which strategies worked and which
did not work for them.  I thought that strategies used may have had an
effect on time and errors.  I did a multiple regression on the Stick Test
strategies and found that 5 of the 11 strategies accounted for most of
the variance in time to completion.

The Stick Test uses 10 patterns of 5 inch long by 1/2 inch wide, flat
sticks with one white tip.  The examiner arranges 2, 3, or 4 sticks in a
pattern and the subject who is sitting across the table must arrange her
sticks to look to her as the examiners sticks look to the examiner.  In
other words, the subject has to up-down and left-right reverse the
pattern.  Five of the patterns use only sticks placed in a
vertical/horizontal orientation and 5 patterns use sticks placed on a
diagonal orientation only.

When I did a pilot study of the Stick Test and plotted each subjects
time on the two orinetation dimensions subjects times seemed to fall
into 1 of 2 patterns, but, on further testing, this did not hold up.

If anybody has any ideas about a better way to analyze the data I would
apprecite hearing them.

Thanks in advance.

Pat Alfano
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Date:         Tue, 21 Jul 1992 12:47:28 -0500
From:         "Gary A. Cziko" <g-cziko@UIUC.EDU>
Subject:      Portable Demos
X-To:         Control Systems Group Network CSGnet <csg-l@vmd.cso.uiuc.edu>

[from Gary Cziko 920721.1215]

For the Durango meeting next week, I am compiling a list of portable
demonstrations of perceptual control and will demonstrate a few of my own.

I think I have already included most of the demos mentioned in the net plus
the classic ones, but I fear I may have missed a few, particularly ones
involving cooperation-conflict in social situations.

If you have a portable demo that you don't think I know about, please clue
me in.  I know that Clark McPhail uses some demos involving BIG rubber
bands in his sociology class, but I don't know exactly how this work.

I will eventually compile all of these and make them available on the
fileserver.--Gary

------------------------------------------------------------------
Gary A. Cziko                    Telephone: (217) 333-4382
Educational Psychology           FAX: (217) 244-0538
University of Illinois           E-mail: g-cziko@uiuc.edu
1310 S. Sixth Street             Radio: N9MJZ
210 Education Building
Champaign, Illinois 61820-6990
USA
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Date:         Fri, 24 Jul 1992 04:31:00 GMT
From:         Dag Forssell <0004742580@MCIMAIL.COM>
Subject:      Seminar
X-To:         csg <CSG-L@vmd.cso.uiuc.edu>

[From Dag Forssell (920723)]

>Date:     Mon Jul 20, 1992  1:10 pm  PST
>Subject:  PCT Seminar
>
>Hi!  Professor Robertson gave me a copy of your version 9 letter on  PCT
>and I found it interesting.  I will graduate in December 1992 under the
>BOG Program and with a major in Psych.  Control theory is basic to my
>interest in the field and I will be needing something to do soon.  I
>have many years of business management including the conduct of seminars
>in sensitive areas (equal employment opportunity).  I understand you may
>be looking for someone to deliver your program in the Chicago area.
>Please contact me if you have an interest in discussing this.

How do I contact you? I have no name, no address.

Glad you found my letter interesting. Thanks!

What is BOG program? Is your major in PCT?

I have yet to get my first customer. If I get one in Chicago, I will
teach myself. I am sure my program will be modified as it meets reality
beyond trial runs with groups of acquaintances. I am not looking for
associates. In fact, I am sure that for the first year at least I will
not have any, if ever. I know other consultant/trainer people who prize
their independence and control. It seems to me that a program like I am
designing by its nature is quite personalized. My convictions are rooted
in my engineering background and extensive reading and living with PCT.
I don't know how anyone else could just deliver my program and be
prepared to answer questions that are bound to come up about why it is
the way it is, or what I mean by a certain illustration.

As you may conclude, I have no great interest in discussing this for the
purpose of an association, at least not now. However, the world can use
thousands of consultants who teach PCT and do it justice. I am quite
willing to discuss that in general.

Dag Forssell
23903 Via Flamenco
Valencia, Ca 91355-2808
Phone (805) 254-1195    Fax (805) 254-7956
Internet:  0004742580@MCIMAIL.COM
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Date:         Thu, 30 Jul 1992 08:57:11 EDT
From:         "Bruce E. Nevin" <bnevin@CCB.BBN.COM>
Subject:      thanks for Closed Loop
X-To:         csg-l%vmd.cso.uiuc.edu@bbn.com
X-cc:         bn@ccb.bbn.com

[From: Bruce Nevin (Thu 920730 08:54:12)]

Thank you, Greg, and all others involved in putting together the
current number of Closed Loop.  This may both prompt and help me
to remedy my educational deficit re statistics.

	Bruce
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Date:         Mon, 20 Jul 1992 10:40:09 EDT
From:         mmt@BEN.DCIEM.DND.CA
Subject: Re: A Bomb in the Hierarchy

[Martin Taylor 920720 10:30]
(Rick Marken 920719.1300)

Rick says that his spreadsheet modelling indicates that one can't have
a masked positive feedback loop within the hierarchy.  Modelling is certainly
superior to wordsmithing, but I remain unconvinced.  Since I came across
the idea, I seem to see it in a lot of apparently inappropriate human behaviour
including suicide, which seems to correspond exactly to this situation.

Rick, I guess I will have to do a little more analysis.  But are you absolutely
sure about your spreadsheet analysis?  There are issues of computational
order and the gain regime within which masking will happen, aren't there?
In the situation I envisage, if Z acts alone, it will display negative
feedback and be able stably to control its percept, because if B, C, and D
have the same impedance, the effects of Z on b and c will swamp those on D.
You say that your model agrees with this.  If the effective impedance of
B and C is reduced by Y, this should make Z more stable, but if it is increased
by Y opposing Z's action on them, then the effect of Z on D should be
relatively more important, and at some point the overall Z loop should go
positive.  If this doesn't show up when modelled, I'd like to understand
why not.  How is the effective gain of Z affected by the action of Y?

I don't see how you can reconcile:
> It is true that system Z can control it's perception
>even with the wrong output connection to one component of that
>perception -- at least over the range of references I investigated.

with
> The result was that there
>is no "collaborative" way for systems Y and Z to control
>their perceptions when system Z has an inappropriate connection
>to one of the variables it is controlling.

You mean Z can control if it acts alone, but never if Y is also acting, even
if Y is affecting B and C in the same sense that Z is?

Martin
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Date:         Mon, 27 Jul 1992 15:36:33 +0200
From:         Oded Maler <Oded.Maler@IRISA.FR>
Subject: Re: Justifying the Blues

From: Oded Maler (920727)

[I promised myself to refrain from participating in this kind
of things, at least till I get a position, but it's stronger
than me].

I don't know if it will comfort you but in the Aix summer
school, Tom Bourbon's talk, and PCT ideas were some of the
*least* controversial. Many people accepted them (though
some without understanding them [not to mention *really*
understanding them..]) {I'm not sure whether this would have
been the case if Rick was presenting them :-}

While explaining what I know to CS/robotics people, the usual
misunderstandings came by (the name "control theory" confused
with the math/engineering discipline, B is the C of P which
is really a truism for roboticists (also not for cognitivists),
etc.)

Concerning Bill P.'s criticism of Brooks, the latter didn't agree with
Bill's insistence that higher-level CS don't have direct access to
low-level sensors (he indicated also biological evidence for direct
pathways). I think the recent CSG discussion (which I didn't read)
about functional vs. anatomical connections is relevant. He was not
convinced either that it is useful to see everything in terms of
servoing and references, especially in the higher-levels.

And a last advice for some dedicated PCTers: you shouldn't adopt
a too PCT-centric point of view - there's much work going on biology
and psychology which is neither pro nor contra-PCT, but rather
orthogonal, by asking different questions, by investigating cognitive
functions where HPCT is nomt more than a reasonable guess, etc.
One's frustration of being rejected from a certain esoteric community
called Psychology should not be taken too seriously.

Best regards

--Oded
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Date:         Wed, 22 Jul 1992 17:16:41 -0600
From:         "William T. Powers" <POWERS_W%FLC@VAXF.COLORADO.EDU>
Subject:      S
X-To:         CSG-L@vmd.cso.uiuc.edu

Hello, Martin --

I have an ulterior motive in throwing that problem back into your lap.
Right now the CSG has only three people actively developing simulations and
doing HPCT experiments: Rick Marken, Tom Bourbon, and me. That isn't
enough. Rick and Tom both began, when they started working with me, with
only a rudimentary understanding of BASIC and no real-time simulation
experience at all. Both of them have since become quite expert in this
field and no longer need me to show the way.

You are probably farther ahead than either of them were, by a long
distance, in all regards. But I'm going to be frank with you: you have a
tendency to sit on your butt and try to figure things out in general and in
the abstract without carrying the ideas to the stage of actual testing. I
would love to get you out from behind that desk and into some programming
of real experiments and simulations. You would obviously be extremely good
at it. You are already very proficient at analysis; there would be less cut
and try for you than there is for me. I expect that you already do, or at
least supervise, a lot of this kind of experimentation and stimulation --
but not in HPCT.

I understand what you mean about simulations vs. analysis. But an analysis
contains far more in it than you will ever notice (even when it's done
right). The analysis stage is extremely useful for looking at
sensitivities, singularities, extremums, and so on. I use it a lot that
way, within my capacities. But a simulation of something you think you
already understand through analysis, I guarantee you, will produce both
surprises and shocks -- and sometimes delight. Analysis can't give you a
grasp of control theory anything like what you can get out of writing and
running even a SIMPLE simulation of a SIMPLE control process. There is
nothing in analytical forms to suggest solving for different variables, re-
expressing the forms in ways that reveal new relationships, and so on. No
matter how much you know already, a simulation will teach you more.

I hope you'll brush up your programming techniques by trying some simple
control system simulations before you get into the complexities; do some
five-finger exercises first. I'm here to help.

I've had more than one excited phone call from Rick and Tom over the years,
saying "You won't believe this, but this stuff ACTUALLY WORKS!" Join the
party.

Best,

Bill

PS: I wish you were coming to Durango, too.
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Date:         Mon, 27 Jul 1992 14:20:30 EDT
From:         "Bruce E. Nevin" <bnevin@CCB.BBN.COM>
Subject:      anyone get back to van Loon?
X-To:         csg-l%vmd.cso.uiuc.edu@bbn.com

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Date:         Thu, 23 Jul 1992 12:31:12 EDT
Reply-To:     Cybernetics and Systems
 <CYBSYS-L%BINGVMB.BITNET@pucc.Princeton.EDU>
 <CYBSYS-L%BINGVMB.BITNET@pucc.Princeton.EDU>
From:         Cliff Joslyn <cybsys@bingsuns.cc.binghamton.edu>
Subject:      New member
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 <CYBSYS-L%BINGVMB.BITNET@pucc.Princeton.EDU>

Really-From: John_Van_Loon.XRCC%xerox.com@BINGVMB.cc.binghamton.edu
Date: 	Wed, 22 Jul 1992 08:30:08 PDT

     Hi,
           My name is John van Loon and I am currently in my last year of
electrical engineering at McMaster University in Ontario Canada.  I am most
interested in robotics and control,  that is, I love working on all aspects of
robots from Neuronet integrated intelligence to motor control and installation.
The problem is that my experience is severely limited to what I can afford to
fund myself.  As a thesis I will be responsible for the   design and
construction of a mobile base and manipulator system for a self-controlled
robot.  In addition to this I will also be working to help develop the
supervisory controls of this robot.  The more that I see  and learn, the more
interested and fascinated I become with the whole art of cybernetics.

     If there are any discussion groups established for walking robots,
sensory developement, and hand/manipulator control please send me a short note
about your group and an address where I can E-Mail you.
 					Thank you,
					John van Loon.
--------------------------------------------------------------
     John van Loon: John_Van_Loon.XRCC%xerox.com@uunet.ca
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Date:         Wed, 22 Jul 1992 10:20:24 -0600
From:         "William T. Powers" <POWERS_W%FLC@VAXF.COLORADO.EDU>
Subject:      Simulating a bomb
X-To:         CSG-L@vmd.cso.uiuc.edu

[From Bill Powers (920722.0930)]

Martin Taylor (920722.1100) --

>Consider a CEV with output gain G controlling the percept x+y, where x >is
based on the CEV "X" and y on "Y".  Disregarding disturbances on "X" >and
"Y" the value of x and y depend on the output O of the ECS. x=XO >and y=yO.
The percept p=O(X+Y).  Let us make the sign of the output >such that
positive signs mean negative feedback (i.e. choose the >comparator sign
appropriately in the ECS).  As described, everything is >fine.

I interpret this to mean:

Initialize: X = 0; Y = 0; O = 0; G = 0.01;
            r = 100;
do
{
x = X; y = Y;
p = x + y;
e = r - p;
O = O + G*e;     /* integrating output function */
X = O; Y = O;
printf(variables)
}
while (!kbhit());

>Now change the sign of the output relation to Y, so that y=-YO and >p=O(X-
Y). ...

>Suppose that for some values of x, dx/dO (i.e. X) is large, whereas for
>other values it is small

I interpret these changes to mean:

Initialize: X = 0; Y = 0; O = 0; G = 0.01;
            r = 100;

for(k=0.25; k <= 2.0; k += 0.25)
do
{
x = X; Y = y;
p = x - y;
e = r - p;
O = O + G*e;     /* integrating output function */
X = k*O; Y = -O;
printf(variables)
}
while (!kbhit());

>Still everything is OK so long as X>Y. Now comes the bomb.
>Suppose that for some values of x, dx/dO (i.e. X) is large, whereas for
>other values it is small--the ECS has, for example, pushed an object >off
a slippery surface onto a sticky one.  Then the ECS will control >fine so
long as x stays in the high compliance (large X) region, but >will go into
a positive feedback condition when "X" becomes stiffer >(the object goes
onto the sticky surface).

Is this what actually happens? I'm not going to tell you. You tell me. If
my interpretations above are OK, make the programs runnable and run them
and let me know what happens. Otherwise, substitute your own program, run
it, and let me know what the program is and what happens.

You don't know what will happen until you simulate the situation. Are you
right or wrong? Find out.
----------------------------------------------------------------------
Best,


Bill P.
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Date:         Tue, 21 Jul 1992 18:43:07 EDT
From:         mmt@BEN.DCIEM.DND.CA
Subject: Re: No bomb in hierarchy

[Martin Taylor 920721 18:30]
(Rick Marken 920720.1130)

>Actually, what I found in the simulation is that two control systems,
>one with the wrong connection to one envrionmental variable, DO blow
>up. I took this to mean that there was no way to "hide" a "positive
>feedback system" in the hierarchy, as Martin suggested.

Actually, I think they needn't blow up.  I don't know whether my message in
response to your simulation result ever got distributed, but your result is
"intuitively" correct.  If Z is the ECS with the bad connection, and Y affects
some variable alse affected by Z, then the fact of Y controlling will tend
to stabilize or "stiffen" that variable.  Z will be acting more through any
overlapping variables, increasing the cotnribution by the one with the
positive feedback, and reducing Z's effective negative gain.  If Y stiffens
enough the overlapping variables, then Z will go into positive feedback.
Whether this happens depends both on the gain of Y and the degree of overlap
between Y and Z.  Of course, if Y overlaps on the variable with the positive
feedback, it will help Z to stabilize.

I think that there are parts of this situation that require a dynamic analysis
rather than the DC analysis Bill produced.  And yes, Bill, the expressions
get horrendous.  After getting Rick's result, I went through the algenbra
to get the result discussed above.

Martin
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Date:         Mon, 27 Jul 1992 19:48:00 GMT
From:         Hortideas Publishing <0004972767@MCIMAIL.COM>
Subject:      Blues, 2 (%)
X-To:         CSGnet <CSG-L@vmd.cso.uiuc.edu>

From Greg Williams (920727-2)

>Rick Marken (920727.1000)

GW>>My prescription: ignore the "wrongs" and concentrate on
GW>>publicizing the "right." In particular, I suggest showing how PCT can
GW>>explain numerous empirical findings already in the literature. That should
GW>>keep PCTers too busy to be depressed.

>I would be happy to do this. But what I have discovered (recently) is that
>most (say 90%+) of these empirical findings are of such LOW QUALITY
>(being statistical results -- the highest degree of relationship I found
>while perusing published studies was .90; not bad, but still not good
>enough for doing modeling) that they are really NOT RESULTS.

I would be surprised if high quality results amount to as much as 2% of the
total.

>An unfortunate implication of PCT
>is that there are almost NO empirical findings of any use to the PCT
>modeller in the current, standard psychological literature. PCTers may
>not have collected hugh amounts of research data in big research projects
>but I've looked through a lot of journals lately and unless one considers
>noisy statistical results to be data, conventional psych ain't got much
>data either.

Still, the good 2% (or maybe more) would keep PCTers busy for a long time in
ways which could be perceived as relevant by non-PCT psychologists. In fact,
there's more than enough to keep PCTers busy for a long time just in the sub-
sub-sub-field of limb trajectories!

Greg
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