HDTenEightyP/NetNews huggingface dataset:
From: "USENET News System" <news@unix.cis.pitt.edu>
Subject: Generator Simulation Program needed -- PLEASE!
Originator: hlab@milton.u.washington.edu
Organization: University of Pittsburgh
Date: Fri, 10 Apr 1992 19:45:50 GMT




        This is my second posting of this request; so far I've only
gotten one response, and THAT one was a request for me to pass along
what I might get.
        Someone out there MUST have a simulation program like the
one below -- I CAN'T believe such an elementary and elegant thermodynamic/
physics/engineering problem hasn't been coded in MULTIPLE times.
        So please, respond!

--------------

        I'm hoping there are a few wizards out there who can help me 
with the following problem.

        I need a program which will simulate, NUMBER-wise (the displays
will be driven by the numbers -- display program already exists) the
operation of a simplistic steam plant: i.e., boiler with water, steam to 
turbine, turbine spinning, generating power from the spin, condensing
the water, and returning the water to the boiler for another cycle.

        The inputs which are to be able to be adjusted by the user
(possibly by running this program as a subprogram) are :
        1) Fuel flow to boiler
        2) Water to boiler from condenser -- obviously with controls to prevent
overfilling boiler or allowing water to come from condenser when there
is none
        3) A makeup pump (for possible lost water), only on/off in nature.
I'd like, however, to be able to possibly modify the amount of water that
the makeup pump delivers when on, not while running the program but to
be able to set it at different levels.

        The outputs are to be the boiler water level and the speed of
the turbine.

        Concealed inputs (ones that the USER won't control, but which
will be passed to the simulator from the external program) will be
the load on the generator and "trip" inputs -- booleans which will trigger
a FAILURE in some part of the system, either a boiler leak, a steam leak,
or a condenser leak.

        The program is to be run on a Sun SPARCstation. The other programs
it is to work with are written in C, so obviously it's got to be compatible
with the other programs.

        One thing it does NOT have to do is be mathematically/physically
perfect. It DOES have to be good enough so that an engineer could watch
the behavior of the system and say "close enough", but it doesn't have
to do thermodynamic modeling of a steamplant cycle if simpler mathematics
will do.

        I'm SURE some such programs exist -- it's a relatively elementary
problem in engineering; I'm looking for a good source program, one that
has been tested (hopefully) and I can get working quickly.


                        Thanks,

                                        Ryk E. Spoor
                                        SEAWASP@vm2.cis.pitt.edu
                                     or seawasp@unixd1.cis.pitt.edu
From: speth@cats.UCSC.EDU (James Gustave)
Newsgroups: sci.virtual-worlds
Subject: LAW and TECH: Glove Emulator Idea
Date: 13 Apr 92 17:16:12 GMT
Organization: University of California, Santa Cruz
Originator: hlab@milton.u.washington.edu


Here's a question that I've had for a while...

I have a PowerGlove communicating with my Mac through an HC11 interface.
I would like to make it emulate a commercial glove.
What proprietary rights does a glove manufacturer (such as VPL) have on their
glove communications standards??

Here's a hypothetical scenario:
  Big VR Company, Inc. makes a product, SuperGlove, which sells for $10k.
It communicates with a generic computer over RS-232 and RS-422 lines at a
changeable baud rate.  To send a command to the glove, the host sends a 3
byte signal, a start-command-flag, followed by two bytes which determine
the command.  In response, the glove-controller sends back a variably long
string of bytes.  One start-flag, one length byte, and a bunch of data bytes.

The exact format and list of commands is printed up in the SuperGlove user's
manual.  It's a very simple system, which lets SuperGlove work with any
machine with a serial port.

I want to make my PowerGlove work with Big VR Company's SuperGlove software.
I'd do this by making the HC11 accept the same format of commands as is
described in the SuperGlove manual (which I can borrow from a rich friend
who has actually bought a SuperGlove).

My questions:
Is a simple command format, such as this, copyright-able?
If I borrow the manual, could I use the information in it to write my
  glove box code?

I'd love to get any opinions on this.
Thanks.


-- 
Jim Speth
speth@cats.ucsc.edu
From: ih3e@uvacs.cs.Virginia.EDU (Jan Hoenisch)
Newsgroups: sci.virtual-worlds
Subject: APPS: New Sega Game
Date: 15 Apr 92 20:43:44 GMT
Organization: UVa Computer Science Dept.
Originator: hlab@milton.u.washington.edu


Does anyone have any more info on the game described below?  
Thanks, Jan

--------------------------------------------------------------------


In article <NB920330.4@clarinet.com>, newsbytes@clarinet.com writes:
TOKYO, JAPAN, 1992 MAR 30 (NB) -- Sega Enterprises claims to have
developed a new computer graphics board designed for game-playing
which is based on the latest concept of "virtual reality."

Sega's "Model 1," also called the virtual reality board, will be 
shipped with Sega's newest game machine by July. Able to be 
connected to a television set, this virtual reality board is said
to create a three-dimensional environment. Sega defines that as
high-quality graphics which support a maximum of 180,000 kinds of 
graphic shapes per second. This allows game programs to respond to
high-speed reactions of the users. The board has also a quality 
sound stereo speaker system, the company says.

Another advantage of this virtual reality board is the networking
feature. It has an extension port to support a multiple player
device. With this device, several players can share
the same game at once.
 
Sega hasn't announced any titles for this new game machine yet,
but the games are expected to be a step above current technology.
Sega claims the virtual reality feature will provide game players
with the feeling of actually participating in the game. Sega says
the technology can be used with special head-gear. 
 
(Masayuki Miyazawa/19920330/Press Contact: Sega Enterprises, +81-
3-5461-8331)

-- 
--------------------------------------------------------------------
Jan Hoenisch (ih3e@virginia.edu) or (ih3e@uvacs.cs.virginia.edu)
Graduate Student, Computer Science Department, Thornton Hall,
University of Virginia, Charlottesville, VA 22903-2442 
Virtual reality is REAL; How real is virtuality?
--------------------------------------------------------------------
From: andrey@cco.caltech.edu (Andre T. Yew)
Newsgroups: sci.virtual-worlds
Subject: TECH: Interesting Power Glove news
Date: 14 Apr 92 18:29:44 GMT
Organization: California Institute of Technology, Pasadena
Originator: hlab@milton.u.washington.edu



        Here's an interesting clip from comp.sys.sgi about a new low cost
glove (see, using really expensive stuff can benefit the low-end too, :).
I'm posting it here because the glovelist doesn't seem to be working
for me.

        (I've edited out some of the non-relevance.  If you must see the
whole article, see comp.sys.sgi and look for some title with PowerGlove
in it.)

--Andre

----

    Check out the CHI '91 proceedings (Human Factors in Computing Systems;
Addison Wesley 51278) from ACM Press.  There is an article titled "Virtual
Reality on Five Dollars a Day" by Randy Pausch from the University of Virginia.

In that article, Randy describes how he got the PowerGlove to work on an
IBM-PC compatible.  The following is an excerpt from that article:

"...as a serial device communicating over an RS232 line.  AGE and VPL
Research have recently announced the VPL/AGE Power Glove Education
Support Program [26] and plan to provide a low cost glove with 5 degree
of freedom for between 150 and 200 dollars."
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

[26] Zachary, G., and Gentile, C., "Personal Communication" (letter),
VPL Research, Inc., July 18 1990.  VPL/AGE Power Glove Support Program,
VPL Research, Inc., 656 Bair Island Road, Suite 304, Redwood City, CA
94063, (415) 361-1710.

Dave Marks
Rome Laboratory
marks@ra.rl.af.mil
----

-- 
Andre Yew                            andrey@tybalt.caltech.edu (131.215.48.100)

[Moderator (Mark): Interested in Randy Pausch's paper?  Get it!  It's located 
        on milton.u.washington.edu, in ~ftp/public/virtual-worlds/papers!]
From: bs@gauss.mitre.org (Robert D. Silverman)
Newsgroups: sci.math
Subject: Re: Series involving primes
Date: 31 Mar 92 20:05:31 GMT
Article-I.D.: linus.1992Mar31.200531.9836
Organization: Research Computer Facility, MITRE Corporation, Bedford, MA

In article <1992Mar30.173346.1602@ifi.uio.no> einarr@ifi.uio.no (Einar Andreas R|dland) writes:
:However, I'd like to know if
:
:    oo
:   ---      1 
:   >    ---------
:   ---  p(i) d(i)
:   i=1
:
:converges.

Yes it does. We have the above sum equal to the following Stieltjes
integral:

integral from 2 to infty of  f(x) d[pi(x)]  where f(x) is:

	1
 -------------------------
x log^2 x (1 + O(1/log^k x))
 
f(x) is obtained by using the PNT. p(i) ~ i log i   and
 d(i) ~ log i (1+O(1/log^k i))  for some constant k.
 
and pi(x) is the prime counting function.

The above integral is finite, so the sum is finite.

--
Bob Silverman
These are my opinions and not MITRE's.
Mitre Corporation, Bedford, MA 01730
"You can lead a horse's ass to knowledge, but you can't make him think"
Newsgroups: sci.math
From: orourke@sophia.smith.edu (Joseph O'Rourke)
Subject: Re: Erdos (was Re: Fermat's Last Theorem)
Organization: Smith College, Northampton, MA, US
Date: Tue, 14 Apr 1992 19:52:54 GMT

In article <1992Apr14.090047.29346@sbil.co.uk> 
	pbond@spitws100.sbil.co.uk writes:

>I would be interested in seeing a list of some of Erdos' problems. Can anybody
>supply a few ? Many thanks.

	I'm not going to answer this question directly, but I just 
noticed that there is a category in Mathematical Reviews, 52C10, 
entitled `Erdo"s problems and related topics of discrete geometry.'
Interesting that he has his own MR category!
Xref: sparky sci.math:5955 comp.theory:1082
From: jmlake@grimm.cogsci.uiuc.edu (J M Lake)
Newsgroups: sci.math,comp.theory
Subject: Re: factorial function
Date: 11 Apr 92 19:38:42 GMT
Article-I.D.: ux1.1992Apr11.193842.7913
Distribution: usa
Organization: University of Illinois at Urbana

djimenez@ringer.cs.utsa.edu (Daniel Jimenez) writes:
>If we can calculate n! mod 100000, we can know the last few digits
>of n!, assuming the algorithm lends itself to modulus like
>exponentiation does.

	n! mod 100000 = 0 for all n > 24.

Mike
--
J. Michael Lake          Beckman Institute for Advanced Science and Technology
Dept. of Comp. Science           jmlake@uiuc.edu             Urbana, IL  61801
Newsgroups: sci.math
From: davidc@uhics.ics.Hawaii.Edu (David Conrad)
Subject: Request for info: primality testing and factorization
Keywords: prime
Organization: University of Hawaii
Date: Tue, 7 Apr 1992 04:58:04 GMT

With all the discussion about the new prime number, I thought this
would be a good group to ask.  I'm looking for references to papers,
etc. on primality testing and factorization.  Please send responses
to me, as I don't read this group often.  If there's any interest,
I'll summarize to the net.

Thanks,
-drc

Xref: sparky sci.math:6151 rec.music.dementia:601
From: duve@ellis.uchicago.edu (michael andrew duvernois)
Newsgroups: sci.math,rec.music.dementia
Subject: Re: Math songs?
Date: 17 Apr 92 20:00:26 GMT
Article-I.D.: midway.1992Apr17.200026.11761
Reply-To: duve@midway.uchicago.edu
Organization: University of Chicago Computing Organizations

In article <22787@dog.ee.lbl.gov> sichase@csa1.lbl.gov writes:
>In article <1992Apr17.142606.920@drycas.club.cc.cmu.edu>, fenthe@drycas.club.cc.cmu.edu writes...
>>Does anyone have any mathematical songs (mnemonic ideally, but
>
I seem to recall a novelty song on the radio about Nicholai Alexander
Lobachevski.  (Spelled incorrectly no doubt.)  It was about the whole
publish or perish situation in math and science.  It stuck with me
for a while and the words "Nicholai Alexander Lobachevski was his name"
occasionally come into my head for no good reason.

Michael DuVernois                              m-duvernois@uchicago.edu
Disclaimer: They really don't care what I say.
Organization: Brigham Young University
Date: Friday, 17 Apr 1992 11:16:13 MDT
From: Stewart J Mayhew <ECOSJMG@BYUVM.BITNET>
Newsgroups: sci.math
Subject: Request concerning Jensen's Inequality

(Also posted in sci.math.stat)

Could somebody please e-mail me a simple statement of Jensen's Inequality
and either the proof or a reference where I can find it?
Thanks in advance.
Newsgroups: sci.math
From: wilson@glitch.cs.jhu.edu (Dwight Wilson)
Subject: Re: Does Goedel's work apply to number theory?
Organization: The Johns Hopkins University CS Department
Distribution: usa
Date: Fri, 10 Apr 1992 01:50:32 GMT

In article <1992Apr9.224106.4243@wdl.loral.com> mab@wdl39.wdl.loral.com (Mark A Biggar) writes:
>In article <1992Apr9.213653.965@aero.org> sinclair@aero.org (William S. Sinclair) writes:
>>A colleague where I work insists that Goedel's work shows that there
>>can be unprovable statements in the field of number theory. Even if they
>>exist, are the any KNOWN unprovable statements in this field? Has there 
>>been much conjecuture about the prvability of conjectures such as Fermat's
>>theorem, or Goldbach's conjecture?
>
>I believe that the following problem has been shown to be undecidable in first
>order logic + peano axioms (which should be sufficient for number threory):
>
>Call a finite set in positive integers LARGE if the smallest member
>of the set is greater then the number of elements in the set.
>
>Take the set of numbers 1..N and partition them as follows: randomly
>select a pair out of the set and color (label) one of the pair BLUE
>and the other RED.  Continue selecting pairs without replacement and coloring
>until the set is empty (if N is odd randomly color the left over element).
>
>Now for any given k, show that there exists a sufficiently large N such that
>it is guarenteed that the will exist a LARGE subset of the RED numbers
>containing k elements.
>

This is the Paris-Harrington statement, which is indeed unprovable
in Peano arithmetic.  For more information consult Ramsey Theory,
by Graham, Rothschild, and Spencer (which has just been cited
in another thread).  

-Dwight
Xref: sparky sci.math:5786 alt.fractals:815
From: joshua@wiretap.wiretap.Spies.COM (Joshua Geller)
Newsgroups: sci.math,alt.irc
Subject: Re: electronic math seminar?
Date: 11 Apr 92 14:26:58 GMT
Distribution: sci
Organization: Institute for the Study of Ancient Science
In-reply-to: jk87377@cc.tut.fi's message of 10 Apr 92 13:56:25 GMT


IRC would be suitable for your conference. You should use one
of the emacs-lisp IRC clients (which allow editing of your own 
lines, killing and redisplaying of someone elses lines, stores
your entire IRC session in a buffer by default (with this line
in your .emacs file: (setq irc-maximum-size nil)).

when you form your channel you should set the mode to +ni (no
messages from outside the channel and invite only).

summoning people to the conference is another problem; you will
have to either arrange the meeting in advance or summon people 
who are online using 'talk' or some such.

emacs irc clients are available on anonymous ftp at various places;
csd.bu.edu, slopoke.mlb.semi.harris.com, nic.funet.edu, 
coombs.anu.edu.au.

josh
From: loeb@geocub.UUCP (Daniel LOEB)
Newsgroups: sci.math
Subject: Iterated Differences
Date: 8 Apr 92 11:54:41 GMT

Consider the following problem. 
Write down n numbers in a row.			8	10	1 	6
Then write down their absolute differneces	    2        9      5
And continue to do so					7	4
Until there is only one number left			     3 

In total, there are n(n+1)/2 numbers written. Say the you have "won",
if (as above) each number from 1 to n(n+1)/2 appears exactly once.

It is possible to win for n = 1 to 5.
(I have an exhaustive list of winning triangles, and it might amuse
you to see how many you can find....)

If have PROVEN using a parity argument, that it is IMPOSSIBLE to win
for n = 6, 14, 30, 62, 126, ..., 2^{i} - 2, ....   
Ask me if you like details of the proof, or try to prove it yourself
(it is not too hard). 

A colleague of mine thought he had proven that it is IMPOSSIBLE for
all n>5 however his proof is flawed. Via an exhaustive computer search
(relying in part on my parity argument) I have showed that there are
no winning triangles for n = 7 or 8. Above n=8, the problem seems
intractable. 

Anyone have any ideas how we may continue.

Thanks.

Yours, Daniel Loeb				loeb@geocub.greco-prog.fr
HOME 	150, cours Victor-Hugo; Appt D45; 33000 Bordeaux France
WORK	LABRI; Universite de Bordeaux I; 33405 Talence Cedex France
PHONE(H)+(33) 56 31 48 26, (W)+(33) 56 84 69 05, (FAX) +(33) 56 84 66 69
-------------
Where a calculator on the ENIAC is equipped with 18,000 vacuum tubes and weighs
30 tons, computers in the future may have only 1,000 vacuum tubes and weigh
only 1 1/2 tons.			---Popular Mechanics, March  1949
Newsgroups: sci.math
Subject: Re: On expected convergence
From: news@massey.ac.nz (USENET News System)
Date: Mon, 13 Apr 92 02:56:45 GMT
Organization: Massey University

Congratulations, you have just invented summability!

Cesaro used a slightly different approach: a series a_0 + a_1 + a_2 + ...
is summable C1 to a if the series s_0 + s_1/2 + s_2/3 + ... converges to a.
That is, the series of averages of partial sums converges. It can be proved
that a convergent series is summable C1 to its sum.

If that does't work the we can use the C1 method on the averages of the
partial sums. This gives summability C2. In general we can have summability
Cn for any n. Riesz has given an even more general method.

Also you could try Borel method (summable B):
                         2        3
 lim  a_0 + a_1*x + a_2*x  + a_3*x  + ...
x->0+

which often converges.

What use is it? Well, at least summability C1 is useful in the theory of
Fourier series. A Fourier series may fail to converge at some points but
it may be summable C1 - and this may be easier to prove than convergence
even where the series does converge.
From: bs@gauss.mitre.org (Robert D. Silverman)
Newsgroups: sci.math
Subject: Re: New Mersenne prime discovered
Date: 9 Apr 92 13:25:49 GMT
Article-I.D.: linus.1992Apr9.132549.24451
Organization: Research Computer Facility, MITRE Corporation, Bedford, MA

In article <pete.02ff@bignode.equinox.gen.nz> pete@bignode.equinox.gen.nz (Pete Moore) writes:
:While skimming through some articles on Mersenne numbers, I found
:`The New Mersenne Conjecture' by Bateman, Selfridge and Wagstaff, 
:published in `American Mathematical Monthly' in February 1989.
:They made the following conjecture:
:
:   If two of the following statements about an odd positive integer p
:   are true, then the third is also true:
:     (1) p = 2^k plus or minus 1   or   p = 4^k plus or minus 3 
:     (2) 2^p-1  is prime  
:     (3) (2^p+1)/3  is prime
:
:It is easy to see that the conjecture holds if p is composite, since then
:both (2) and (3) are false.
:B, S & W included a table listing odd primes p which were known to satisfy
:(1),(2) or (3), up to the limits 1E6, 1E5 and 4000 respectively. All
:satisfied the conjecture.
:
:As noted in this newsgroup, it has recently been discovered that
:p=756839 gives a Mersenne prime. For what it's worth, the conjecture
:also holds for p=756839: while I was typing this posting, a background
:process I'm running found that (2^p+1)/3 is divisible by 1640826953.
:
:Does anyone know how far the conjecture has been verified, and in
:particular, whether a counter-example has been found?
 
The 'conjecture' is based upon some coincidences that work for SMALL
exponents. It is observed that M127 and (2^127+1)/3 are both prime.
Probabalistically one can look at p > 127 and come to the conclusion
that for this to happen again is highly improbable.

Let me quote John Selfridge, who originally put forth this 'conjecture'.

It is certainly true, and equally certainly it will never be proved.

Counter examples are beyond the range of current computers. There is no known
method that will allow us to prove (2^p+1)/3 is prime for p much above 5000.
[There is no equivalent to the Lucas-Lehmer test for 2^p+1/3]

--
Bob Silverman
These are my opinions and not MITRE's.
Mitre Corporation, Bedford, MA 01730
"You can lead a horse's ass to knowledge, but you can't make him think"
Newsgroups: sci.math
From: delliott@cec2.wustl.edu (Dave Elliott)
Subject: Re: ARE equations
Organization: Washington University, St. Louis Mo.
Date: Sun, 12 Apr 1992 00:59:03 GMT


For Algebraic Riccati Equations see "Linear Systems" by Thomas Kailath
(Prentice-Hall 1980) or any other graduate-level text on linear [control]
systems. 
                                David L. Elliott
				Dept. of Systems Science and Mathematics
                                Washington University, St. Louis, MO 63130
				delliott@CEC2.WUSTL.EDU
Xref: sparky sci.math:5695 sci.crypt:1821
From: elkies@ramanujan.harvard.edu (Noam Elkies)
Newsgroups: sci.math,sci.crypt
Subject: Tangent^2 re: Mersenne
Summary: nitpick
Date: 7 Apr 92 03:11:47 GMT
Organization: Harvard Math Department

In article <1992Apr1.185322.22929@linus.mitre.org>
bs@gauss.mitre.org (Robert D. Silverman) writes:

> Now, if [p is prime and] 2p+1 is prime, then it will divide 2^p-1
>with probability 1/2. (Theorem! This arises from quadratic reciprocity
>and the fact that 2 is a quadratic residue of 1/2 the primes).

Whoa --- one also needs that half the primes p *such that 2p+1 is prime*
are congruent to 1 mod 4; it is still a big open problem to prove that
there are infinitely many such p to begin with!  I certainly have no
reasonable doubt that there are infinitely many, and that they are
correctly distributed mod 4, but a "Theorem!" it isn't.

--Noam D. Elkies (elkies@zariski.harvard.edu)
  Department of Mathematics, Harvard University
From: ags@mentor.cc.purdue.edu (Dave Seaman)
Newsgroups: sci.math
Subject: Re: factoid about new prime
Date: 8 Apr 92 16:45:35 GMT
Organization: Purdue University Computing Center

In article <57048@cup.portal.com> ts@cup.portal.com (Tim W Smith) writes:
>No, the *value* of the new prime is 2.3E162781 times the *value* of the old
>one.  The size is 3.5 times.  It would take 3.5 times as much space to
>write it.

What you call the *value* of the new prime is in fact the new prime itself.
What you call the *size* of the new prime is not the size of the number at all,
but only the size of *the name of the new prime*, using decimal notation.

Q. Which is larger, Chicago or Albuquerque?
A. Chicago has more people.

Q. Which is larger, the population of Chicago or the population of Albuquerque?
A. I have already answered that.

Q. Which is larger, "Chicago" or "Albuquerque"?
A. "Albuquerque" has more letters.

The original poster was correct. CNN understated the ratio of the numbers.

-- 
Dave Seaman
ags@seaman.cc.purdue.edu
Newsgroups: sci.math
From: mlevin@forte.cs.tufts.edu
Subject: need a recent reference to Julia sets
Organization: Tufts University
Distribution: usa
Date: Fri, 10 Apr 1992 02:13:24 GMT


      I am looking for a recent reference (a paper?) on Julia sets,
that I can use to backward search for other references (I need one
with an extensive bibliography). I am also looking for any references
on using Julia sets to simulate biological, chemical, or physical
processes. Please send info to mlevin@presto.cs.tufts.edu.

Mike Levin
From: dabbott@augean.eleceng.adelaide.edu.AU (Derek Abbott)
Newsgroups: sci.math
Subject: distribution of wealth
Date: 6 Apr 92 06:10:33 GMT
Organization: Electrical and Electronic Eng., University of Adelaide


If you added up everbody's bank balances, in the world, and then
divided by the world population, what would we all get??

A lot or a little?