HDTenEightyP/NetNews huggingface dataset:
From: jbaez@nevanlinna.mit.edu (John C. Baez)
Newsgroups: sci.physics
Subject: Re: Sorry sorry sorry
Date: 22 Aug 92 23:03:43 GMT
Organization: MIT Department of Mathematics, Cambridge, MA

In article <8400013@trsvax> pauls@trsvax.tandy.com writes:
>
>1) Ge.. I'm sorry all your ARROGANT non-engineers are so touchy. Maybe its
>the fact Gov. Bill might take your pork away in Texas.
>
>2) My post wasn't an ad.
>
>3) If I've done some unspeakable horrible tabu sensitive thing (apparantly
>scott chase has gone nuclear (pun!)) I'm sorry. See..I am used to posting
>into areas like rec.audio and rec.music.synth where 99% of the posts are
>"ads" just like mine was. ie hey this new synthesizer just came out, here
>are the specs, here is the price, check it out. That was my ONLY intention.
>
>sorry sorry sorry sorry.
>

It's best to make up your mind whether you want to be apologetic or
obnoxious BEFORE you post.  If you took a look at sci.physics before you
posted you would note that there are no adverstisements in it.  If you
work for Tandy and were advertising a Tandy product, that's definitely
against the usenet rules, at least for the sci groups.
From: sichase@csa2.lbl.gov (SCOTT I CHASE)
Newsgroups: sci.physics
Subject: Re: Hubble constant?
Date: 16 Aug 92 19:15:17 GMT
Organization: Lawrence Berkeley Laboratory - Berkeley, CA, USA
Distribution: na
Reply-To: sichase@csa2.lbl.gov
NNTP-Posting-Host: 128.3.254.197
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>In article <Aug.13.16.31.25.1992.25521@ruhets.rutgers.edu> bweiner@ruhets.rutgers.edu (Benjamin Weiner) writes:
> 
>>I like the 
>>baryonic possibilities because we already know that baryons exist,
>>and in addition I would rather that dark matter were something
>>astronomically interesting, like so-called Pop III star remnants
>>or whatever, rather than a bunch of dull photinos.

For those of you interesting in the Dark Matter problem, I would like 
to call your attention to an article in last week's Nature reporting the
results of a survey of low-mass stars in our galaxy and an extrapolation
of the mass spectrum which results.  The conclusion is that low-mass,
very-low-magnitude stars can account for much, but not all of the 
dark matter in our galaxy.  I'm not an expert, so I can't judge the 
credibility of the results, but I can at least say that the authors 
make what seems to be a convincing case that we have up to now undercounted 
low-mass stars.

-Scott

--------------------
Scott I. Chase			"The question seems to be of such a character
SICHASE@CSA2.LBL.GOV		that if I should come to life after my death
				and some mathematician were to tell me that it
				had been definitely settled, I think I would
				immediately drop dead again."      - Vandiver
From: sichase@csa2.lbl.gov (SCOTT I CHASE)
Newsgroups: sci.physics
Subject: Re: Hubble constant?
Date: 20 Aug 92 02:57:06 GMT
Organization: Lawrence Berkeley Laboratory - Berkeley, CA, USA
Distribution: na
Reply-To: sichase@csa2.lbl.gov
NNTP-Posting-Host: 128.3.254.197
News-Software: VAX/VMS VNEWS 1.3-4   

In article <Aug.18.21.15.05.1992.16614@ruhets.rutgers.edu>, bweiner@ruhets.rutgers.edu (Benjamin Weiner) writes...
> 
>I'm Dale Bass's evil twin.  Or maybe I'm Dale Bass.  Have you ever
>seen me and Dale in the same room at the same time?

Maybe you're identical fermions.  Then you could not be Dale Bass and still
never be in the same room at the same time.

-Scott
--------------------
Scott I. Chase			"The question seems to be of such a character
SICHASE@CSA2.LBL.GOV		that if I should come to life after my death
				and some mathematician were to tell me that it
				had been definitely settled, I think I would
				immediately drop dead again."      - Vandiver
From: ted@physics2 (Emory F. Bunn)
Newsgroups: sci.physics
Subject: Re: math for physics
Date: 14 Aug 1992 18:41:04 GMT
Organization: /etc/organization
NNTP-Posting-Host: physics2.berkeley.edu

In article <4720045@hpcc01.corp.hp.com> flower@hpcc01.corp.hp.com (Graham Flower) writes:
>
(Request for information about books on mathematical physics, specifically:)
>
>       Morse and Feshbach            
>       Courant and Hilbert           
>       Arfken                        
>       whittaker and watson          
>       Weinberger's PDE book         
>       Bukov                       
>       Boas                 

I haven't used very many of these books, but I'll spit a couple of opinions
at you from my experience.

If you want to find practical formulae for solving specific problems, 
Arfken is quite good.  You're right that it doesn't go into as much 
depth as some of the others, but what it has is good.  If you're looking
for information on Legendre functions, Bessel functions, or spherical
harmonics, Jackson is an easy place to look things up.  (There's a special
table of contents on the back page specifically referring to these
functions.)  Since its an electrodynamics book, it doesn't have anything
on the special functions that are useful mainly in quantum mechanics
(Hermite polynomials, etc.)

There are also lots of useful formulae in the huge integral table by
Gradzhteyn (Spelled way wrong, I'm sure.)

I've talked about where to find specific formulae, because that's what I've
done the most of.  If you want to know about the theory behind  
special functions and diff. eq.'s, you'll have to look elsewhere.
I like Courant and Hilbert, but it's expensive (even in used bookstores).
I've never found Bukov to be especially useful, and I'm not especially
familiar with the others.

By the way, Jeffries and Jeffries is another book some people would 
include on your list.  I've never used it, so I'm not recommending it.
Just pointing out that it exists.

-Ted
From: sichase@csa3.lbl.gov (SCOTT I CHASE)
Newsgroups: sci.physics
Subject: Re: The dangers in microwaved food...
Date: 20 Aug 92 21:31:19 GMT
Organization: Lawrence Berkeley Laboratory - Berkeley, CA, USA
Distribution: na
Reply-To: sichase@csa3.lbl.gov
NNTP-Posting-Host: 128.3.254.198
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In article <1992Aug20.195003.26103@noose.ecn.purdue.edu>, muttiah@stable.ecn.purdue.edu (Ranjan S Muttiah) writes...
>In article <25626@dog.ee.lbl.gov> sichase@csa3.lbl.gov writes:
>>From the barrage of witty cracks and diversions, you would think that 
>>this poor guy was posting about space potatos or something.
>				             ^
> 
>I just couldn't resist.  You forgot the "missing" e Scott! :-).  It's
>an election year you know :-).

You know, I wrote it with the 'e' and then thought "Wait a minute... I'll
look silly if I put an 'e' in potato.  It looks right, but... I can't risk
looking as stupid as Dan Quayle."  So I deleted it!

I guess that the microwaved egg is on my face today.


-Scott  
--------------------
Scott I. Chase			"The question seems to be of such a character
SICHASE@CSA2.LBL.GOV		that if I should come to life after my death
				and some mathematician were to tell me that it
				had been definitely settled, I think I would
				immediately drop dead again."      - Vandiver
From: sichase@csa2.lbl.gov (SCOTT I CHASE)
Newsgroups: sci.physics
Subject: Re: sea waves
Date: 19 Aug 92 01:07:45 GMT
Organization: Lawrence Berkeley Laboratory - Berkeley, CA, USA
Reply-To: sichase@csa2.lbl.gov
NNTP-Posting-Host: 128.3.254.197
Summary: waves colour
Keywords: waves
News-Software: VAX/VMS VNEWS 1.3-4   

In article <boudouvi.714144870@theseas>, boudouvi@ntua.gr (Andreas Boudouvis) writes...
> 
>A summer-time question:
>Why the crests of sea waves are white (esop. when the waves 
>break at the seashore?)

Neat question.  The answer must be "turbulence."  Presumably, the turbulant 
water on the crest scatters light without preference  to wavelength (at least
in the visable), leading to white caps.  I am no expert on turbulence, but
I believe that it is characterized by fluctuations on many length scales,
which leads to the scattering of all wavelengths.  

-Scott
--------------------
Scott I. Chase			"The question seems to be of such a character
SICHASE@CSA2.LBL.GOV		that if I should come to life after my death
				and some mathematician were to tell me that it
				had been definitely settled, I think I would
				immediately drop dead again."      - Vandiver
Newsgroups: sci.physics,sci.astro
From: silverstein@vxdesy.desy.de
Subject: Re: Fossil Paradox (was: Structure of Time)
Organization: (DESY, Hamburg, Germany)
Date: Mon, 17 Aug 1992 17:49:22 GMT

In article <1992Aug17.105752.29021@cco.caltech.edu>, keith@cco.caltech.edu (Keith Allan Schneider) writes:
> bedding@physics.su.OZ.AU (Tim Bedding) writes:
> 
>>In article <1992Aug17.105608.421@ecc.tased.edu.au> ecc_jim@ecc.tased.edu.au writes:
>>>
>>>There was a short story like this where a guy trod on a butterfly and totally
>>>changed everything. What was it called?
>>>
>>"The Sound of Thunder", as I recall.  Which was what he heard when he got
>>back to the present to find it changed: his travelling partner blew him
>>away with a shotgun for being a jerk.  :-)
> 
> That wasn't the story I think he was talking about.  If I remember, the
> story he mentioned ended just when the man returns to the present (he had
> been back in time hunting dinosaurs or something--they would figure out 
> when it would die, and then let people shoot it a moment before.  Then, 
> the bullets would be collected, etc.  There was this walkway, but
> the man stepped off it and onto a butterfly.), finding that the spelling
> of a few words on a sign were changed.
> 
> I read this story in 8th grade but cannot recall the title.
> 
> keith
> 

You're both talking about the same story. Not only was the spelling of the sign
changed, but a different president (one who was against time travel) had just
gotten elected.

Sam
From: sichase@csa2.lbl.gov (SCOTT I CHASE)
Newsgroups: sci.physics
Subject: Re: Order-of-Magnitude problems
Date: 17 Aug 92 21:13:41 GMT
Organization: Lawrence Berkeley Laboratory - Berkeley, CA, USA
Distribution: na
Reply-To: sichase@csa2.lbl.gov
NNTP-Posting-Host: 128.3.254.197
News-Software: VAX/VMS VNEWS 1.3-4   

>Rob Salgado (sal7@ellis.uchicago.edu) wrote:
>:         In trying to improve my physical intuition, I've been doing lots
>: of Order-Of-Magnitude (Back-Of-The-Envelope) problems.  
>: ...but I'm stumped by the following:
>:  
>:         Use the uncertainty principle to compute how long an ordinary
>:         lead pencil can be balanced upside down on its point.
>:                                                 [QM: Das/Melissinos p. 53]
>: Any ideas?

Sure.  There are two competing effects which you have to analyze.  Where they
cross is the longest survival time.  First there is the classical time for 
the pencial to drop, which you can easily calculate, given that it is 
at an initial angle of inclination from the vertical, theta.

Second is the position-momentum uncertainty, which tells you that 
dX*dP > h-bar/2, or taking dP = m*dX/dt gives you a relationship between 
dX and dt.  

The classical effect gives you a longer lifetime for smaller theta.  The
QM effect gives you, for sufficiently small theta, a large dP, i.e., a 
shorter lifetime.  The theta (or dX) which gives you the best balance
between the two effects will define the maximum lifetime of the pencil 
before falling.

I would work out the numbers for you, but I don't have an envelope handy. :-)

-Scott
--------------------
Scott I. Chase			"The question seems to be of such a character
SICHASE@CSA2.LBL.GOV		that if I should come to life after my death
				and some mathematician were to tell me that it
				had been definitely settled, I think I would
				immediately drop dead again."      - Vandiver
Newsgroups: sci.physics
From: sichase@csa2.lbl.gov (SCOTT I CHASE)
Newsgroups: sci.physics,alt.religion.kibology
Subject: Re: Kibocolliders (was: Re: Super Conducting Supercollider)
Date: 12 Aug 92 19:02:04 GMT
Reply-To: sichase@csa2.lbl.gov
Distribution: na
Organization: Lawrence Berkeley Laboratory - Berkeley, CA, USA
NNTP-Posting-Host: 128.3.254.197
News-Software: VAX/VMS VNEWS 1.3-4

In article <1992Aug12.053828.8192@nuscc.nus.sg>, matmcinn@nuscc.nus.sg (Mcinnes B T (Dr)) writes...
>Scott: the horrible truth is that none of these guys has any idea who or
>what Kibo is. They are just pretending. A bit like physics actually.

Maybe.  But now I do - and from none other than Kibo himself, who E-mailed
a few comments, with a .sig so long that I couldn't read it all in 5 minutes
of trying.  

He seems to be one of those folks who are famous for being famous - kinda
like Charles Nelson Riley or the Gabor sisters.

-Scott
--------------------
Scott I. Chase			"The question seems to be of such a character
SICHASE@CSA2.LBL.GOV		that if I should come to life after my death
				and some mathematician were to tell me that it
				had been definitely settled, I think I would
				immediately drop dead again."      - Vandiver
From: ag3l+@andrew.cmu.edu (Arun K. Gupta)
Newsgroups: sci.physics
Subject: Speculation
Date: 23 Aug 92 08:12:36 GMT
Article-I.D.: andrew.ceZvXoS00VAw40q60q
Organization: Physics, Carnegie Mellon, Pittsburgh, PA



If we had a theory of electrons of charge -e, and heavy positively
charged (say 41 e) particles, then the lowest energy state given
that a bunch of these particles was in existence in a certain volume
would be: a superconducting crystalline solid, in which the electro-
magnetic gauge invariance would be spontaneously broken, at least for
energy scales of 1/100 of an eV. What I mean here is that the long-
wave length photon has an effective mass.
Does anyone else find this weird ? I find it hard to digest. And the
question arises: does something similarly wierd happen in the strong
interactions, if I have three quarks in a certain volume ?

-arun
From: sichase@csa2.lbl.gov (SCOTT I CHASE)
Newsgroups: sci.physics
Subject: Re: Superbashing (was Re: SARFATTI LECTURES ON SUPER PHYSICS #1)
Date: 12 Aug 92 19:13:50 GMT
Article-I.D.: dog.25428
Reply-To: sichase@csa2.lbl.gov
Distribution: na
Organization: Lawrence Berkeley Laboratory - Berkeley, CA, USA
NNTP-Posting-Host: 128.3.254.197
News-Software: VAX/VMS VNEWS 1.3-4

In article <phfrom.238@nyx.uni-konstanz.de>, phfrom@nyx.uni-konstanz.de (Hartmut Frommert) writes...
> 
>any supersymmetry. So there's no experimental, phenomenological, or 
>theoretical evidence for SS. (See also John C. Baez's posting)

That's not the way I understand it.  If you take the SM by itself, there
are intrinsic problems which are guaranteed to arise at sufficiently high
energy.  In loose terms, the Higgs particle behaves badly at high energy,
causing "violation of unitarity," i.e., probabilities for certain processes
are predicted to be greater than unity.  If I remember correctly, these
problems arise with quadratic Higgs self-couplings and longitudinal W-W 
scattering.

Although we have not yet probed the energy scale at which this arises,
so that in the strict sense you are correct that there is no experimental 
evidence for SS, we know that the problems are coming and that SS is 
a way out, which offers additional theoretical appeal on other fronts
as well.  

I think that it would be fair to consider these problems with the SM 
as some "theoretical" evidence for SS or some other theory which is 
mathematically similar.

-Scott

--------------------
Scott I. Chase			"The question seems to be of such a character
SICHASE@CSA2.LBL.GOV		that if I should come to life after my death
				and some mathematician were to tell me that it
				had been definitely settled, I think I would
				immediately drop dead again."      - Vandiver
From: johan@blade.stack.urc.tue.nl (Johan Wevers)
Newsgroups: sci.physics
Subject: Re: FTL
Date: 17 Aug 92 14:22:48 GMT
Organization: MCGV Stack, Eindhoven University of Technology, the Netherlands.

Nir.Oren@f54.n7101.z5.fidonet.org (Nir Oren) writes:

>Using the uncertanty principle, is it possible to travel faster than 
>the speed of light: A particles exact speed can't be mesured 
>ks>|for an exact period of time, therefore, could one not exceed 
>the speed of light, if he were then to slow down below it for an 
>equal ( or slightly greater) amount of time?

That's true. According to Feynman's book ``QCD'', the traveling of
a photon is can be described as a combination of a lot of Feynman
diagrams, in which the photon sometimes decays into a particle-
antiparticle pair, and so on. As far as I understood it, each (virtual)
photon traveled with speed c, but the net result was an uncertancy
on macroscopic scale. However, usually this uncertancy is very small,
but maybe measurable.

I'm not an expert on this subject, so please correct me if I put
something not totally correct.

 ********************************************************************
 * J.C.A. Wevers                *         u\  _\       /e+        2 *
 * johan@blade.stack.urc.tue.nl *     1 |   \ u \  X  /         |   *
 ******************************** P = - |    >   >---<     + ...|   *
 *     The only nature of       *     N |   /   /     \         |   *
 *     reality is physics       *         u/   /d     u\            *
 ********************************************************************
From: agnew@gems.vcu.edu
Newsgroups: sci.image.processing
Subject: RE: art gallery flame apology
Date: 21 Aug 92 12:38:57 GMT
Organization: Medical College of Virginia

Dear all.

  In stupidly looking at my reply after I sent it, (It was to the poster
who was saying that Japan was better at making stuff), I am now sorry I 
sent such a usless flame.  I apologize to all on this list.  Please, do not
start a flame war, they are useless.  Japan is better at a lot of things,
the U.S. at others.  We are all going thru a global depression right now,
and teamwork is needed rather than flaming or running keyboards uselessly.
I will do my part and shut up.  This is my own responsibility.  

  Now, back to image processing, and no more trade wars....

  Jim.


-- 
         /^^^\   \ /   Jim Agnew         AGNEW@RUBY.VCU.EDU  (Internet)
        /      >  ||   Neurosurgery,     AGNEW@VCUVAX        (Bitnet)
   /\_/     '   \  /   MCV-VCU           This tape will self destruct in
 /________________>    Richmond, Va      five seconds.  Good luck, Jim..."
From: maynard@tamar.msc.cornell.edu (Maynard J. Handley)
Newsgroups: sci.image.processing
Subject: Re: image processing loops: a c programming question
Date: 22 Aug 92 05:17:23 GMT
Distribution: sci.image.processing
Organization: Cornell-Materials-Science-Center

In article <ben.714157437@galaxy>, ben@ph.tn.tudelft.nl (Ben Verwer)
writes:
>The basic question is how to program for images with variable sizes. The 
>solution presented by the author here (malloc a linear array of
>xsize*ysize) is
>imo the best. Those numerical recipies in C readers who propose the famous
>>array of pointers solution are thinking rather 2d. What if you go to 3d:
>an 
>image of pointers? Which is of course implemented as an array of pointers
>to 
>pointers. Good luck!
>As for the author who proposed the function call in the innerloop: you
>must 
>drink lots of coffee at work :)
>
Why not do what I do and have the best of both worlds? Allocate one long
array of nx*ny doubles, then an array of nx double*s, each of which points
to the appropriate section of the previous array. Operations that naturally
run across the entire array can be coded like that, and operations that
make use of the 2Dness of the array can be coded like that. You also have
something you can pass to Fortran. Of course I wrap it up in a C++ class to
hide the ugly details of creating and destroying the objects each time I
use them.

Maynard Handley
Newsgroups: sci.image.processing,comp.compression
From: rvk@isl.Stanford.EDU (Rick A. VanderKam)
Subject: Re: Compressing halftone images
Organization: Stanford University
Date: Fri, 14 Aug 92 18:04:46 GMT

In article <sjreeves.920810102554@eng.auburn.edu> sjreeves@eng.auburn.edu (Stan Reeves) writes:
>
>I read in SP Magazine that "coding of halftone images, once thought to
>have great promise, has not been successful."  I would like to find out
>more information about this.  Can someone summarize what's been done in
>this area and just how "unsucessful" the efforts have been?
>
>Stan Reeves
>Auburn University, Department of Electrical Engineering, Auburn, AL  36849
>INTERNET: sjreeves@eng.auburn.edu


I can't give an exhaustive summary, but can perhaps get you started.
I'll assume that you're referring to binary (monochrome) rather than
color halftoning.  There seems to be relatively more research activity
in the area of halftoning per se than there is in the area of
compression of halftoned images.  If you are interested in halftoning
by itself, see the Proceedings of the ICASSP-91, ICASSP-92, and
SPIE-92 conferences for some of the most recent proposed methods.  A
few (not all) of the relevant names are Neuhoff & Pappas, Zakhor, and
Allebach.  There is also Ulichney's book, _Digital Halftoning_, put
out by MIT Press (1987), which presents a variety of analyses on a
variety of halftoning techniques.

There are two forms of compression that you might be interested
in---lossless and lossy.  For lossless (noiseless, no information
loss) compression, the most promising method (in my opinion) is IBM's
Q-coder, which is documented by about five articles in the _IBM
Journal of Research and Development_, November, 1988 (Vol. 32, No. 6).
These articles have other useful references as well.  IBM is working
to have their system established as part of the Joint Binary Image
Group (JBIG) standard for compression.  It seems to be an excellent
noiseless coding scheme, which routinely produces coding rates that
achieve or beat the first-order entropy for a variety of halftoned
images. 

For lossy compression, there have been a couple of published works in
which the halftoning and compression are done separately (Neuhoff &
Pappas, ICASSP-91; Y.-M. Chao, "An Investigation into the Coding of
Halftone Images," Ph.D. thesis, MIT, 1987).  I co-authored a paper at
ICASSP-92 showing that a better idea is to do the halftoning and
compression jointly.  In that paper, we showed an image compressed at
about 11:1 which looks pretty decent (we think!).  We are continuing
to work on this problem here at Stanford.  Hope this helps....

Rick A. Vander Kam
rvk@isl.stanford.edu
From: alien@essex.ac.uk ("Adrian F Clark")
Newsgroups: sci.image.processing
Subject: Re: FFT's. Help with Region Segmentation
Date: 13 Aug 92 11:02:00 GMT
	<ck.713491034@iconix.oz.au>
Organization: University of Essex, UK
In-reply-to: ck@iconix.oz.au's message of 10 Aug 92 23:57:14 GMT


In article <ck.713491034@iconix.oz.au> ck@iconix.oz.au (Chris Karadaglis) writes:

> Ok. Understood. But exactly what does it contain? I just can't seem to
> grasp what the phase information in a 2d FFT actually means. I'm after
> an intuitive answer, not a mathematical one. With 1d signals, it's a
> little bit easier.

I don't understand your confusion.  The meaning of phase in a 2-D
image is _precisely_ the same as that of phase in a 1-D signal: each
pixel (sample) in the image (signal) has a modulus component and a
phase component.  Think of it in a vector way: the modulus is the
length of an arrow with its blunt end at the origin, and the phase
gives the direction in which the arrowhead points.

This is why it's important not to fiddle with the phase when filtering
(which fiddles with the amplitude).  There are demonstrations of the
relative importance published, such as mixing the phase of one image's
FT with the amplitude of another image's FT and then inverting the
transform: the `phase image' is usually dominant.

--
 Dr Adrian F. Clark                                   JANET: alien@uk.ac.essex
 INTERNET: alien%uk.ac.essex@nsfnet-relay.ac.uk          FAX: (+44) 206-872900
 BITNET: alien%uk.ac.essex@ac.uk              PHONE: (+44) 206-872432 (direct)
 Dept ESE, University of Essex, Wivenhoe Park, Colchester, Essex, C04 3SQ, UK.
From: frost@sdsc.edu (Richard Frost)
Newsgroups: sci.image.processing
Subject: where is FAQ ??
Date: 13 Aug 1992 21:54:50 GMT
Organization: San Diego Supercomputer Center @UCSD.
Distribution: world
Reply-To: frost@sdsc.edu
NNTP-Posting-Host: stimpy.sdsc.edu
Keywords: where is FAQ

Is there an FAQ for this group?  If so, where is it archived?

Thanks!