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AIList Digest Volume 2 Issue 013
AIList Digest Sunday, 5 Feb 1984 Volume 2 : Issue 13
Today's Topics:
Brain Theory - Parallelism,
Seminars -
Feb 7th CSD Colloquium
[STORY: Neural networks]
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Date: 31 Jan 84 09:15:02 EST (Tue)
From: Dana S. Nau <dsn%umcp-cs@CSNet-Relay>
Subject: parallel processing in the brain
From: Rene Bach <BACH@SUMEX-AIM.ARPA>
What are the evidences that the brain is a parallel processor? My own
introspection seem to indicate that mine is doing time-sharing. That is
I can follow only one idea at a time, but with a lot of switching
between reasoning paths (often more non directed than controlled
switching).
Does that mean you hold your breath and stop thinking while you're
walking, and stop walking in order to breathe or think?
More pointedly, I think it's incorrect to consider only
consciously-controlled processes when we talk about whether or not
the brain is doing parallel processing. Perhaps the conscious part
of your mind can keep track of only one thing at a time, but most
(probably >90%) of the processing done by the brain is subconscious.
For example, most of us have to think a LOT about what we're doing
when we're first learning to drive. But after a while, it becomes
largely automatic, and the conscious part of our mind is freed to
think about other things while we're driving.
As another example, have you ever had the experience of trying
unsuccessfully to remember something, and later remembering
whatever-it-was while you were thinking about something else?
SOME kind of processing was going on in the interim, or you
wouldn't have remembered whatever-it-was.
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Date: 30 Jan 84 20:18:33-PST (Mon)
From: pur-ee!uiucdcs!parsec!ctvax!uokvax!andree @ Ucb-Vax
Subject: Re: intelligence and genius - (nf)
Article-I.D.: uiucdcs.5259
Sorry, js@psuvax, but I DO know something about what I spoke, even if I do
have trouble typing.
I am aware that theorom-proving machines are impossible. It's also fairly
obvious that they would use lots of time and space.
However, I didn't even MENTION them. I talked about two flavors of machine.
One generated well-formed strings, and the other said whether they were
true or not. I didn't say either machine proved them. My point was that the
second of these machines is also impossible, and is closely related to
Jerry's genius finding machines. [I assume that any statement containing
genius is true.]
Down with replying without reading!
<mike
------------------------------
Date: Wed, 1 Feb 84 13:54:21 PST
From: Richard Foy <foy@AEROSPACE>
Subject: Brain Processing
The Feb Scientific American has an article entitled "The
Skill of Typing" which can help one to form insights into
mechanisms of the brains processing.
richard
------------------------------
Date: Thu, 2 Feb 84 08:24:35 PST
From: Charlie Crummer <crummer@AEROSPACE>
Subject: AIList Digest V2 #10
Re: Parallel Processing in the Brain
There are several instances of people experiencing what can most easily
be explained as "tasking" in the brain. (an essay by Henri Poincare in "The
World of Mathematics", "The Seamless Web" by Stanley Burnshaw) It appears
that the conscious mind is rather clumsy at creative work and in large measure
assigns tasks (in parallel) to the subconscious mind which operates in the
background. When the background task is finished, an interrupt is generated
and the conscious mind becomes aware of the solution without knowing how the
problem was solved.
--Charlie
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Date: Thu 2 Feb 84 10:17:08-PST
From: Kenji Sugiyama <SUGIYAMA@SRI-AI.ARPA>
Subject: Re: Parallel brain?
I had a strange experience when I had practiced abacus in Japan.
An abacus is used for adding, subtracting, multipling, and dividing
numbers. The practice consisted of a set of calculations in a definite
amount of time, say, 15 minutes. During that time, I began to think
of something other than the problem at hand. Then I noticed that
fact ("Aha, I thought of this and that!"), and grinned at myself in
my mind. In spite of these detours, I continued my calculations without
an interruption. This kind of experience repeated several times.
It seems to me that my brain might be parallel, at least, in simple tasks.
------------------------------
Date: 2 Feb 1984 8:16-PST
From: fc%USC-CSE@ECLA.ECLnet
Subject: Re: AIList Digest V2 #10
parallelism in the brain:
Can you walk and chew gum at the same time?
Fred
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Date: Sat, 4 Feb 84 15:06:09 PST
From: Philip Kahn <kahn@UCLA-CS>
Subject: The brain is parallel, yet data flow can be serial...
In response to Rene Bach's question whether "the brain is a parallel
processor." There is no other response other than an emphatic YES! The
brain is comprised of about 10E9 neurons. Each one of those neurons is
making locally autonomous calculations; it's hard to get more parallel than
that! The lower brain functions (e.g., sensory preprocessing, lower motor
control, etc.) are highly distributed and locally autonomous processors (i.e.,
pure parallel data flow). At the higher thought processing levels, however,
it has been shown (can't cite anything, but I can get sources if someone
wants me to dig them out) that logic tends to run in a serial fashion.
That is, the brain is parallel (a hardware structure), yet higher logic
processes apply the timing of thought in a serial nature (a "software"
structure).
It is generally agreed that the brain is an associational
machine; it processes based upon the timing of diffuse stimuli and the
resulting changes in the "action potential" of its member neurons.
"Context" helps to define the strength and structure of those associational
links. Higher thinking is generally a cognitive process where the context
of situations is manipulated. Changing context (and some associational
links) will often result in a "conclusion" significantly different than
previously arrived upon. Higher thought may be thought as a three process
cycle: decision (evaluation of an associational network), reasonability
testing (i.e., is the present decision using a new "context" no different
from the decision arrived upon utilizing the previous "context"?), and
context alteration (i.e., "if my 'decision' is not 'reasonable' what
'contextual association' may be omitted or in error?"). This cycle is
continued until the second step -- 'reasonability testing' -- has concluded
that the result of this 'thinking' process is at least plausible. Although the
implementation (assuming the trichotomy is correct) in the brain is
via parallel neural structures, the movement of information through those
structures is serial in nature. An interesting note on the above trichotomy;
note what occurs when the input to the associational network is changed.
If the new input is not consistent with the previously existing 'context'
then the 'reasonability tester' will cause an automatic readjustment of
the 'context'.
Needless to say, this is not a rigorously proven theory of mine,
but I feel it is quite plausible and that there are profuse psychophysical
and phychological studies that reinforce the above model. As of now, I
use it as a general guiding light in my work with vision systems, but it
seems equally appplicable to general AI.
Philip Kahn
KAHN@UCLA-CS.ARPA
------------------------------
Date: 02/01/84 16:09:21
From: STORY at MIT-MC
Re: Neural networks
[Forwarded by SASW@MIT-ML.]
DATE: Friday, February 3, 1984
TITLE: "NEURAL NETWORKS: A DISCUSSION OF VARIOUS MATHEMATICAL MODELS"
SPEAKER: Margaret Lepley, MIT
Neural networks are of interest to researchers in artificial intelligence,
neurobiology, and even statistical mechanics. Because of their random parallel
structure it is difficult to study the transient behavior of the networks. We
will discuss various mathematical models for neural networks and show how the
behaviors of these models differ. In particular we will investigate
asynchronous vs. synchronous models with undirected vs. directed edges of
various weights.
HOST: Professor Silvio Micali
------------------------------
Date: 01 Feb 84 1832 PST
From: Rod Brooks <ROD@SU-AI>
Subject: Feb 7th CSD Colloquium - Stanford
[Reprinted from the SU-SCORE bboard.]
A Perspective on Automatic Programming
David R. Barstow
Schlumberger-Doll Research
4:30pm, Terman Aud., Tues Feb 7th
Most work in automatic programming has focused primarily on the roles of
deduction and programming knowledge. However, the role played by knowledge
of the task domain seems to be at least as important, both for the usability
of an automatic programming system and for the feasibility of building one
which works on non-trivial problems. This perspective has evolved during
the course of a variety of studies over the last several years, including
detailed examination of existing software for a particular domain
(quantitaive interpretation of oil well logs) and the implementation
of an experimental automatic programming system for that domain. The
importance of domain knowledge has two importatnt implications: a primary goal
of automatic programming research should be to characterize the programming
process for specific domains; and a crucial issue to be addressed
in these characterizations is the interaction of domain and programming
knowledge during program synthesis.
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End of AIList Digest
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