simulation@uflorida.cis.ufl.edu (Moderator: Paul Fishwick) (08/22/90)
Volume: 17, Issue: 4, Wed Aug 22 10:16:59 EDT 1990
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| TODAY'S TOPICS |
+----------------+
(1) RE: Simula 67
(2) Simulation Tools in Physical Education
(3) Numerical Integration and Stability
(4) Review of Simulation Tools
(5) RE: MAC Simulation Software (msg 1)
(6) RE: MAC Simulation Software (msg 2)
* Moderator: Paul Fishwick, Univ. of Florida
* Send topical mail to: simulation@bikini.cis.ufl.edu OR
post to comp.simulation via USENET
* Archives available via FTP to bikini.cis.ufl.edu (128.227.224.1).
Login as 'ftp', use your last name as the password, change
directory to pub/simdigest. Do 'type binary' before any file xfers.
* Simulation Tools available by doing above and changing the
directory to pub/simdigest/tools.
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Date: Thu, 9 Aug 90 07:12:41 EST
From: Richard E. Nance - SRC <srcnance@popeye.cs.vt.edu>
To: cho@cs.ucla.edu
Subject: Simulation of Distributed Systems
Cc: simulation@bikini.cis.ufl.edu
=> Organization: UCLA Computer Science Department
=>
=>
=> Hi, Netter,
=>
=> I plan to simulate resource or load management methods in Time Warp, and
=> I am curious whether anyone have already built such simulators.
=> I know that Orna Berry builted one Time Warp simulator, but it was written
=> in SIMULA 67 whose compiler is not available to me.
Simula 67 for Macintosh/MPW is in the public domain and can
be obtained from
Lund Software House AB
Box 7056
S-220 07 LUND
Sweden
or copied from an existing disk which they distribute.
=> cho@cs.ucla.edu
Dick Nance
nance@vtopus.cs.vt.edu
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Return-Path: <cypark@june.cs.washington.edu>
To: comp-simulation@beaver.cs.washington.edu
Path: uw-june!cypark
From: cypark@cs.washington.edu (Chang Yun Park)
Newsgroups: comp.simulation
Subject: REQUEST: high-level tools for physical education
Date: 13 Aug 90 23:06:39 GMT
Organization: U of Washington, Computer Science, Seattle
This inquiry is for my friend in Korea, looking for
simulation packages or languages.
(Originally, he asked the following question to me,
but I couldn't help him. I think this group is the
place to have some ideas.)
Please tell me any hints or guides. I will forward
all of them to him. Thank you.
-------------
As a professor in physical education, he has been thinking
about computer-aided education; for example, he wants to
show his students how a change of running style has effect
on speed. Visualization would be better if possible.
All information in his field was already collected,
and some basic plans of what and how to do are made.
However, he has no idea on how to use computers.
Although he is willing to learn, he doesn't know where he
can start.
Any experiences for similar applications ?
Are there any (commercial) programs or languages easy to
learn and use, and with some graphic display ?
-------------
ChangYun Park
(cypark@june.cs.washington.edu)
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To: comp-simulation@sdcc6.UCSD.EDU
Path: sdcc6!beowulf!heirich
From: aheirich@UCSD.EDU (Alan Heirich)
Newsgroups: comp.simulation
Subject: Continuous System Simulation
Summary: Help: integration of autonomous systems with mixed variables
Keywords: numerical integration, dynamical systems
Date: 17 Aug 90 00:52:41 GMT
Sender: news%sdcc6@ucsd.edu
Distribution: all
Organization: California Institute of Technology
Nntp-Posting-Host: beowulf.ucsd.edu
I am writing a package for simulation of continuous dynamical
systems. The core of simulator is a numerical integration loop.
I have what may be a rather naive question about numerical
integration, and my guess as to an answer to my question. I
would be grateful if any numerical integration experts out
there can tell me whether my head is screwed on straight. In
return for helpful information I would be glad to share my
package when it is ready. (First version is for IBM-AT's).
Most continuous system simulation packages require you to
write first order rate equations. In other words, all differential
equations have the form
d x/d t = f (x, t, ...)
It would be nice to model autonomous systems (where the O.D.E.'s
are not all written with respect to t), e.g.
d x/d t = f (x, t, ...)
d y/d x = g (y, x, ...)
For the sake of argument, assume that you are using 2nd order
Runge-Kutta numerical integration to simulate the trajectories of
your state variable(s) x (and y). Then the second example would
update according to the following rule:
xk1 = f (x, t, ...) * delta_t
xk2 = f (x + xk1, t + delta_t) * delta_t
x_next = x + (xk1 + xk2) / 2
delta_x = x_next - x
yk1 = f (y, x, ...) * delta_x
yk2 = f (y + yk1, x + delta_x) * delta_x
y_next = y + (yk1 + yk2) / 2
My question is this: are common integration methods (like
2nd order Runge-Kutta) numerically stable in this sort of
situation? My guess is that they are not, because the size
of delta_x is not fixed and is hard to predict. Thus the
method might, for example, step over a singularity in the y
trajectory and miss it.
Since I think this answer is probably correct, my *real*
question is: are there any methods which don't have this
problem? Or more generally, how do people manage to simulate
autonomous continuous systems defined by differential equations?
Alan Heirich heirich@aurel.cns.caltech.edu
============================================
Program in Computation and Neural Systems
California Institute of Technology
Pasadena, CA 91125
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To: comp-simulation@ucsd.edu
Path: cod!burkley
From: burkley@cod.nosc.mil (V. J. Burkley)
Newsgroups: comp.simulation
Subject: Review of simulation tools/environments
Date: 17 Aug 90 16:25:52 GMT
Distribution: usa
Organization: Naval Ocean Systems Center, San Diego
Hi, I am somewhat new to creating simulations. I am currently
trying to find out people's experiences with two products. The first
is Simscript II.5 from CACI and the other is SES Workbench (I don't
know who makes it). I would also appreciate any information on other
products that run on Sun workstations that are suitable for large
scale simulations. Please reply to my e-mail. I will post a summary
if there is interest. Thanks.
Joe Burkley
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To: uunet!comp-simulation@uunet.UU.NET
Path: inmet!ma
From: ma@inmet.inmet.com
Newsgroups: comp.simulation
Subject: Simulation tools advice needed
Date: 16 Aug 90 20:06:00 GMT
Nf-Id: #N:inmet:27600001:000:238
Nf-From: inmet.inmet.com!ma Aug 16 16:06:00 1990
I am planning to do some performance modeling of a large distributed
software system. Are there any good simulation tools available on the
Macintosh for doing this? I will appreciate your advice.
malgosia askanas (ma@inmet.inmet.com)
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To: comp-simulation%munnari@munnari.OZ.AU
Path: munnari.oz.au!stats.mu.oz.au!koula
From: koula@stats.mu.oz.au (Koula Courtot 6605)
Newsgroups: comp.simulation,sci.math.stat
Subject: Request for simulation packages
Keywords: simulation
Date: 20 Aug 90 22:53:34 GMT
Sender: news@cs.mu.oz.au
Could anyone please let me know what packages are available on
simulation of random processes for a Macintosh system.
Could you please e-mail your responses to me. My email address
is: koula@mugga.stats.mu.oz.au
Thanks.
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