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AIList Digest Volume 2 Issue 001
AIList Digest Wednesday, 4 Jan 1984 Volume 2 : Issue 1
Today's Topics:
Administrivia - Host List & VISION-LIST,
Cognitive Psychology - Looping Problem,
Programming Languages - Questions,
Logic Programming - Disjunctions,
Vision - Fiber Optic Camera
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Date: Tue 3 Jan 84 15:07:27-PST
From: Ken Laws <Laws@SRI-AI.ARPA>
Reply-to: AIList-Request@SRI-AI
Subject: Host List
The AIList readership has continued to grow throughout the year, and only
a few individuals have asked to be dropped from the distribution network.
I cannot estimate the number of readers receiving AIList through bboards
and remailing nodes, but the existence of such services has obviously
reduced the outgoing net traffic. For those interested in such things,
I present the following approximate list of host machines on my direct
distribution list. Numbers in parentheses indicate individual subscribers;
all other hosts (and those marked with "bb") have redistribution systems.
A few of the individual subscribers are undoubtedly redistributing
AIList to their sites, and a few redistribution nodes receive the list
from other such nodes (e.g., PARC-MAXC from RAND-UNIX). AIList is
also available to USENET through the net.ai distribution system.
AEROSPACE(8), AIDS-UNIX, BBNA(2), BBNG(1), BBN-UNIX(8), BBN-VAX(3),
BERKELEY(3), BITNET@BERKELEY(2), ONYX@BERKELEY(1), UCBCAD@BERKELEY(2),
BRANDEIS(1), BRL(bb+1), BRL-VOC(1), BROWN(1), BUFFALO-CS(1),
cal-unix@SEISMO(1), CIT-20, CMU-CS-A(bb+11) CMU-CS-G(3),
CMU-CS-SPICE(1), CMU-RI-ISL1(1), COLUMBIA-20, CORNELL,
DEC-MARLBORO(7), EDXA@UCL-CS(1), GATECH, HI-MULTICS(bb+1),
CSCKNP@HI-MULTICS(2), SRC@HI-MULTICS(1), houxa@UCLA-LOCUS(1),
HP-HULK(1), IBM-SJ(1), JPL-VAX(1), KESTREL(1), LANL, LLL-MFE(2),
MIT-MC, NADC(2), NOSC(4), NOSC-CC(1), CCVAX@NOSC(3), NPRDC(2),
NRL-AIC, NRL-CSS, NSF-CS, NSWC-WO(2), NYU, TYM@OFFICE(bb+2),
RADC-Multics(1), RADC-TOPS20, RAND-UNIX, RICE, ROCHESTER(2),
RUTGERS(bb+2), S1-C(1), SAIL, SANDIA(bb+1), SCAROLINA(1),
sdcrdcf@UCBVAX(1), SRI-AI(bb+6), SRI-CSL(1), SRI-KL(12), SRI-TSC(3),
SRI-UNIX, SU-AI(2), SUMEX, SUMEX-AIM(2), SU-DSN, SU-SIERRA@SU-DSN(1),
SUNY-SBCS(1), SU-SCORE(11), SU-PSYCH@SU-SCORE(1), TEKTRONIX(1), UBC,
UCBKIM, UCF-CS, UCI, UCL-CS, UCLA-ATS(1), UCLA-LOCUS(bb+1),
UDel-Relay(1), UIUC, UMASS-CS, UMASS-ECE(1), UMCP-CS, UMN-CS(bb+1),
UNC, UPENN, USC-ECL(7), USC-CSE@USC-ECL(2), USC-ECLD@USC-ECL(1),
SU-AI@USC-ECL(4), USC-ECLA(1), USC-ECLB(2), USC-ECLC(2), USC-ISI(5),
USC-ISIB(bb+6), USC-ISID(1), USC-ISIE(2), USC-ISIF(10), UTAH-20(bb+2),
utcsrgv@CCA-UNIX(1), UTEXAS-20, TI@UTEXAS-20(1), WISC-CRYS(3),
WASHINGTON(4), YALE
-- Ken Laws
------------------------------
Date: Fri, 30 Dec 83 15:20:41 PST
From: Philip Kahn <kahn@UCLA-CS>
Subject: Are you interested in a more specialized "VISION-LIST"?
I been feeling frustrated (again). I really like AIList,
since it provides a nice forum for general AI topics. Yet, like
many of you out there, I am primarily a vision researcher looking into
ways to facilitate machine vision and trying to decipher the strange,
all-too-often unknown mechanisms of sight. What we need is a
specialized VISION-LIST to provide a more specific forum that will
foster a greater exchange of ideas among our research.
So...one question and one request: 1) is there such a list in the
works?, and 2) if you are interested in such a list PLEASE SPEAK UP!!
Thanks!
Philip Kahn
UCLA
------------------------------
Date: Fri 30 Dec 83 11:04:17-PST
From: Rene Bach <BACH@SUMEX-AIM.ARPA>
Subject: Loop detection
Mike,
It seems to me that we have an inbuilt mechanism which remembers
what is done (thought) at all times. I.E. we know and remember (more or
less) our train of thoughts. When we get in a loop, the mind is
immediately triggered : at the first element, we think it could be a
coincidence, as more elements are found matching the loop, the more
convinced we get that there is a repeat : the reading example is quite
good , even when just one word appears in the same sentence context
(meaning rather than syntactical context), my mind is triggered and I go
back and check if there is actually a loop or not. Thus to implement this
property in the computer we would need a mechanism able to remember the
path and check whether it has been followed already or not (and how
far), at each step. Detection of repeats of logical rather than word for
word sentences (or sets of ideas) is still left open.
I think that the loop detection mechanism is part of the
memorization process, which is an integral part of the reasoning engine
and it is not sitting "on top" and monitoring the reasoning process from
above.
Rene
------------------------------
Date: 2 January 1984 14:40 EST
From: Herb Lin <LIN @ MIT-ML>
Subject: stupid questions....
Speaking as an interested outsider to AI, I have a few questions that
I hope someone can answer in non-jargon. Any help is greatly appreciated:
1. Just why is a language like LISP better for doing AI stuff than a
language like PASCAL or ADA? In what sense is LISP "more natural" for
simulating cognitive processes? Why can't you do this in more tightly
structured languages like PASCAL?
2. What is the significance of not distinguishing between data and
program in LISP? How does this help?
3. What is the difference between decisions made in a production
system (as I understand it, a production is a construct of the form IF
X is true, then do Y, where X is a condition and Y is a procedure),
and decisions made in a PASCAL program (in which IF statements also
have the same (superficial) form).
many thanks.
------------------------------
Date: 1 Jan 84 1:01:50-PST (Sun)
From: hplabs!hpda!fortune!rpw3 @ Ucb-Vax
Subject: Re: Re: a trivial reasoning problem? - (nf)
Article-I.D.: fortune.2135
Gee, and to a non-Prolog person (me) your problem seemed so simple
(even given the no-exhaustive-search rule). Let's see,
1. At least one of A or B is on = (A v B)
2. If A is on, B is not = (A -> ~B) = (~A v (~B)) [def'n of ->]
3. A and B are binary conditions.
>From #3, we are allowed to use first-order Boolean algebra (WFF'n'PROOF game).
(That is, #3 is a meta-condition.)
So, #1 and #2 together is just (#1) ^ (#2) [using caret ^ for disjunction]
or, #1 ^ #2 = (A v B) ^ (~A v ~B)
(distributivity) = (A ^ ~A) v (A ^ ~B) v (B ^ ~A) v (B ^ ~B)
(from #3 and ^-axiom) = (A ^ ~B) v (B ^ ~A)
(def'n of xor) = A xor B
Hmmm... Maybe I am missing your original question altogether. Is your real
question "How does one enumerate the elements of a state-space (powerset)
for which a certain logical proposition is true without enumerating (examining)
elements of the state-space for which the proposition is false?"?
To me (an ignorant "non-ai" person), this seems excluded by a version of the
First Law of Thermodynamics, namely, the Law of the Excluded Miraculous Sort
(i.e. to tell which of two elements is bigger, you have to look at both).
It seems to me that you must at least look at SOME of the states for which the
proposition is false, or equivalently, you must use the structure of the
formula itself to do the selection (say, while doing a tree-walk). The problem
of the former approach is that the number of "bad" states should be kept
small (for efficiency), leading to all kinds of pruning heuristics; while
for the latter method the problem of elimination of duplicates (assuming
parallel processing) leads to the former method!
In either case, however, reasoning about the variables does not seem to
solve the problem; one must reason about the formulae. If Prolog admits
of constructing such meta-rules, you may have a chance. (I.e., "For all
true formula 'X xor Y', only X need be considered when ~Y, & v-v.)
In any event, I think your problem can be simplified to:
1'. A xor B
2'. A, B are binary variables.
Rob Warnock
UUCP: {sri-unix,amd70,hpda,harpo,ihnp4,allegra}!fortune!rpw3
DDD: (415)595-8444
USPS: Fortune Systems Corp, 101 Twin Dolphins Drive, Redwood City, CA 94065
------------------------------
Date: 28 Dec 83 4:01:48-PST (Wed)
From: hplabs!hpda!fortune!rpw3 @ Ucb-Vax
Subject: Re: REFERENCES FOR SPECIALIZED CAMERA DE - (nf)
Article-I.D.: fortune.2114
Please clarify what you mean by "get close to the focal point of the
optical system". For any lens system I've used (both cameras and TVs),
the imaging surface (the film or the sensor) already IS at the focal point.
As I recall, the formula (for convex lenses) is:
1 1 1
--- = --- + ---
f obj img
where "f" is the focal length of the lens, "obj" the distance to the "object",
and "img" the distance to the (real) image. Solving for minimum "obj + img",
the closest you can get a focused image to the object (using a lens) is 4*f,
with the lens midway between the object and the image (1/f = 1/2f + 1/2f).
Not sure what a bundle of fibers would do for you, since without a lens each
fiber picks up all the light around it within a cone of its numerical
aperture (NA). Some imaging systems DO use fiber bundles directly in contact
with film, but that's generally going the other way (from a CRT to film).
I think Tektronix has a graphics output device like that. I suppose you
could use it if the object were self-luminous...
Rob Warnock
UUCP: {sri-unix,amd70,hpda,harpo,ihnp4,allegra}!fortune!rpw3
DDD: (415)595-8444
USPS: Fortune Systems Corp, 101 Twin Dolphins Drive, Redwood City, CA 94065
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End of AIList Digest
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