HDTenEightyP/NetNews huggingface dataset:
From: wdh@linus.mitre.org (Dale Hall)
Subject: Boundary of Mandelbrot set
Followup-To: sci.fractals
Summary: characterization of S^1
Keywords: circle, characterization, separation properties
Organization: Research Computer Facility, MITRE Corporation, Bedford, MA
Distribution: na
Date: Fri, 6 Nov 1992 18:31:37 GMT

Some time back, someone (whose name and article I've forgotten)
inquired as to whether, since the Mandelbrot set is connected, its
boundary couldn't be shown to be a simple (but nasty) closed curve in
the complex line C.  A response was given in the group, pointing to
current research along that line (and indicating that the question was
still open).  I have nothing new to add to that, only to suppose that
those interested in this issue were aware of the following property
that uniquely characterizes the circle S^1 (and thus would suffice to
determine whether the boundary of the Mandelbrot set is in fact such a
beast):

	The circle is the unique topological space for which:

		1) no single point separates the space

	and

		2) every pair of distinct points does separate the
		   space. 

Here, a set separates a space if its complement is not connected. (so,
for instance, the empty set separates any non-connected space).

Just an observation that might be of some value.

						Dale.



Newsgroups: sci.fractals
From: Gabriel Landini <g.landini@uk.ac.bham>
Subject: Re: Interpolation & Chaotic TS
Date: Thu, 5 Nov 1992 17:07:51 GMT
Organization: The University of Birmingham, United Kingdom

>
>    Given a chaotic time series with a fractal dimension, does anyone know of
>    any theory or whatever which relates splines to the interpolation of the
>    chaotic time series corresponding to the given fractal dimension?  For
>    example, if I have a signal that can be best interpolated by cubic splines,
>    then that is what I would use (using a linear or quadratic spline would not
>    do so well).  Now, given a chaotic time series (perhaps one similar to that
>    of Brownian motion), it would seem that you cannot interpolate it with any
>    spline of some order, or you need a very high order spline in order to
>    interpolate it accurately.  This may sound crazy, but would it be that you
>    would need a spline of some fractional order (in relation to the fractal
>    dimension of the time series) in order to do an accurate interpolation?  Or,
>    would the spline needed have to have fractal properties itself (a fractal
>    interpolating a fractal, so to speak.  I got this idea from Barnsley's IFS
>    where a base fractal is used to interpolate a fractal image).
>
>     If anyone can give me any guidance at all on this problem, I would greatly
>     appreciate it.  Also, any reference to literature that may help me would
>     be nice.
>
>                          John
>
>------------------------------------------------------------------------------

If your time series is chaotic, then your spline will be always in some way
"wrong". What is the point of getting a spline, then?
Do you have any other example?
How do you know that your time series is chaotic?

Gabriel
Newsgroups: sci.fractals
From: noring@netcom.com (Jon Noring)
Subject: Wanted: ftp sites having parameter,formula and map files for Fractint
Organization: Netcom - Online Communication Services  (408 241-9760 guest) 
Date: Thu, 12 Nov 1992 17:13:27 GMT

Hello,

I'd like to know if anybody is archiving parameter, formula and map files
for use by Fractint?  

Much thanks.

Jon Noring

-- 
=============================================================================
| Jon Noring          | noring@netcom.com        | "The dogs bark, but the  |
| JKN International   | IP    : 192.100.81.100   |  caravan moves on."      |
| 1312 Carlton Place  | Phone : (510) 294-8153   | "Pack your lunch, sit in |
| Livermore, CA 94550 | V-Mail: (510) 862-1101   |  the bushes, and watch." |
=============================================================================
"If your annual income today is $50,000, you have the same buying power as
the average coal miner did in 1949, adjusted for taxes and inflation," John
Sestina, nationally recognized Certified Financial Planner;  quoted in 1987.

------->   I VOTED FOR PEROT IN '92
------->   support UNITED WE STAND!
From: mbk@gibbs.ucsd.edu (Matt Kennel)
Newsgroups: sci.fractals
Subject: Re: Interpolation & Chaotic TS
Date: 6 Nov 1992 06:40:38 GMT
Organization: Institute For Nonlinear Science, UCSD
NNTP-Posting-Host: gibbs.ucsd.edu
X-Newsreader: Tin 1.1 PL3

sassoj@rs6416.ecs.rpi.edu (John J. Sasso Jr.) writes:
:     Given a chaotic time series with a fractal dimension, does anyone know of
:     any theory or whatever which relates splines to the interpolation of the
:     chaotic time series corresponding to the given fractal dimension?  For
:     example, if I have a signal that can be best interpolated by cubic splines,
:     then that is what I would use (using a linear or quadratic spline would not
:     do so well).  Now, given a chaotic time series (perhaps one similar to that
:     of Brownian motion), it would seem that you cannot interpolate it with any
:     spline of some order, or you need a very high order spline in order to 
:     interpolate it accurately.  This may sound crazy, but would it be that you
:     would need a spline of some fractional order (in relation to the fractal
:     dimension of the time series) in order to do an accurate interpolation?  Or,
:     would the spline needed have to have fractal properties itself (a fractal
:     interpolating a fractal, so to speak.

What do you mean by "interpolating a fractal?"  

A fractal attractor certainly has a fractal measure and support--but this
is a set, not a function. 

If you mean predicting some value, say the future point of a time series,
given the past and a data set of obseved dynamics, the fractal structure
of the attractor does not really matter--the dynamics (i.e. evolution
function) is supposed to be a smooth function of phase space and thus
easily approximated by splines, even though you observe data only on
some fractal set.

:                           John


--
-Matt Kennel  		mbk@inls1.ucsd.edu
-Institute for Nonlinear Science, University of California, San Diego
-*** AD: Archive for nonlinear dynamics papers & programs: FTP to
-***     lyapunov.ucsd.edu, username "anonymous".
Newsgroups: sci.fractals
From: twegner@mwunix.mitre.org (Timothy Wegner)
Subject: Re: Colour printing with fractint
Organization: The MITRE Corporation
Date: Mon, 9 Nov 1992 14:41:56 GMT

shirriff@sprite.berkeley.edu (Ken Shirriff) writes:

>In article <groot.721065728@jupiter.idca.tds.philips.nl> groot@idca.tds.philips.nl (Henk de Groot) writes:
>>   Both fractint 17.1 AND 17.2 respond on the argument
>>   rleps=yes or 'rleps=yes' or "rleps=yes" with a humming sound and the
>>   message:
>>   *** Error during startup:

>I guess the rleps option didn't get into fractint yet, so ignore my previous
>suggestion of using rleps to fix the color printing problem.

Yes, rleps is not in the DOS Fractint. (Ken knows this - the following is
for everybody else) Ken's Xfractint represents the current state of the
Fractint developer's version, which is not public. Therefore typically there
will be features in Xfract that are not yet in the PC DOS-based Fractint.

The reason for this is that the Fractint authors get a lot of mail and 
questions about Fractint, and we do not want to have to support developer's
versions that change every few days. In the case of Xfract, Ken's doing
the supporting so it's his call :-) Fractint v 18 with rleps will be out
sometime early next year. 

A side comment - with the exception of the ever-improving postscript support,
Fractint printing capability is pretty bad. There is no attempt to render
colors as dithered shades. Folks "in the know" save as GIF and print with
other software. PICLAB does a really good job with HP printers. 
--
Tim Wegner     Fractint co-author
Internet: twegner@mwunix.mitre.org  Compuserve: 71320.675@compuserve.com
Newsgroups: sci.fractals
From: Gabriel Landini <g.landini@uk.ac.bham>
Subject: Re: Fractal and Chaotic music, et al...
Date: Tue, 10 Nov 1992 09:33:11 GMT
Organization: The University of Birmingham, United Kingdom

>Does anyone know of where one can obtain information, or find discussions,
>concerning musical applications of fractals, the 1/f nature of music, source
>code(preferably C, but anything will do), random number generation using
>fractal principles, chaos theory, and musical applications of chaotic systems?
>I would particularly like to know if there are any source code examples of
>anything related to any of these topics. Also, does anyone have info they
>would like to share?
>
>Thanks for your help!
>	- Adam Alpern
>
>
>
>
>--
>Adam Alpern			* "All that is gold does not glitter, not all  *AAlpern@hamp.hampshire.edu	* those who wander are lost." - JRR Tolkien    *				* "When I look in the mirror I see the days to *				* come
>------------------------------------------------------------------------------

I have written a short paper on 1/f noise and its use in music:
G. Landini. Fractal music: The 1/f algorithm. Fractal Report 20, 14-17, 1992.
G.R. Turner. Production of 1/ music series. Fractal Report 22, 16-20, 1992.
G. Landini. Noises, noises & noises. Fractal Report 23, 6-7, 1992.
If you want to subscribe to FR, let me know and I will leave their address
here.
Gabriel (G.Landini@bham.ac.uk)
Newsgroups: sci.fractals
From: mroussel@alchemy.chem.utoronto.ca (Marc Roussel)
Subject: Re: Lorenz' Weather
Organization: Department of Chemistry, University of Toronto
Date: Thu, 12 Nov 1992 20:13:58 GMT

In article <gordon.721582896@tramp.Colorado.EDU> gordon@tramp.Colorado.EDU
(GORDON ALLEN R) writes:
>mrmarcel@eos.ncsu.edu (MICHAEL RONN MARCELAIS) writes:
>>Does anybody have the equations that Lorenz used in his old weather program? 
>>It was the first time he noticed the 'sensitive to initial conditions'
>>phenomenon that started research into Chaos.
>
>	dX/dt = a(Y-X)
>	dY/dt = bX-Y-XZ
>	dZ/dt = XY - cZ
>
>				where a = 10
>				      c = 8/3
>				      b = control parameter (try 28)

     These are indeed the Lorenz equations (as they are now known) but
these aren't the original weather simulation equations where Lorenz
noticed sensitive dependence on initial conditions.  Lorenz actually
started out with some specialized version of the Navier-Stokes equation
(a PDE) and noticed sensitive dependence in these equations under the conditions
of his weather simulation.  The Lorenz ODEs shown above are a truncation
of the Navier-Stokes equation for the special case of (I think)
Rayleigh-Benard convection under certain fairly restrictive conditions.
Lorenz cooked up these equations as a simple example of what he was
seeing in his more sophisticated weather models.

				Marc R. Roussel
                                mroussel@alchemy.chem.utoronto.ca
Newsgroups: sci.fractals
From: noring@netcom.com (Jon Noring)
Subject: Can Resolution in Fractint be increased for Disk/RAM Mode?
Summary: There is currently a 2048x2048 limit.
Organization: Netcom - Online Communication Services  (408 241-9760 guest) 
Date: Mon, 9 Nov 1992 17:52:57 GMT

Hello,

I'm in the process of producing high quality fractal prints/posters using
Fractint v17.2.  To maintain resolution for large posters, I'd like to exceed
the maximum resolution of 2048x2048 in Disk/RAM Mode.

Can this be done by a simple tweaking of the source code, or is it a much more
involved programming job to do this?

Thanks.

Jon Noring


-- 
=============================================================================
| Jon Noring          | noring@netcom.com        | "The dogs bark, but the  |
| JKN International   | IP    : 192.100.81.100   |  caravan moves on."      |
| 1312 Carlton Place  | Phone : (510) 294-8153   | "Pack your lunch, sit in |
| Livermore, CA 94550 | V-Mail: (510) 862-1101   |  the bushes, and watch." |
=============================================================================
"If your annual income today is $50,000, you have the same buying power as
the average coal miner did in 1949, adjusted for taxes and inflation," John
Sestina, nationally recognized Certified Financial Planner;  quoted in 1987.

------->   I VOTED FOR PEROT IN '92
------->   support UNITED WE STAND!

Newsgroups: sci.fractals
From: lmitchel@nyx.cs.du.edu (lloyd mitchell)
Subject: Fractal Data Analysis
Summary: uses fractal compression
Organization: University of Denver, Dept. of Math & Comp. Sci.
Date: Mon, 9 Nov 92 11:21:44 GMT

Entirely too long ago, I posted that I had a paper about data analysis
using fractals, and that I would post the reference.  Well, here it
(finally!) is, if anyone is (still) interested:

Turbulent Combustion Data Analysis Using Fractals, W. Strahle, AIAA
paper 90-0729, 28th Aerospace Sciences Meeting, Jan. 1990.

The abstract reads:

This paper investigates several types of data analysis, based upon fractal
geometry concepts, using time series generated in turbulent combustion
research.  The techniques are quite general and may be used for other
turbulent flows.  Investigated are the generalized fractal dimension, 
multifractal probability density function, fractal filtration, multifractal
spectrum, and fractal interpolation and its possible connection with
chaotic dynamics.  It is concluded that several of the techniques are
useful for a) new visual depiction of the data, b) discrimination of
portions of data traces as noise-contaminated, c) separation of wanted and
unwanted high or low frequency events, and d) interpolation between sparse
data points in either short run time or low data acquisition rate situations.

Sorry for the delay!

Kerry Mitchell
Newsgroups: sci.fractals
From: stam@dgp.toronto.edu (Jos Stam)
Subject: Re: Interpolation & Chaotic TS
Date: 5 Nov 92 16:20:13 GMT

sassoj@rs6416.ecs.rpi.edu (John J. Sasso Jr.) writes:


>    Given a chaotic time series with a fractal dimension, does anyone know of
>    any theory or whatever which relates splines to the interpolation of the
>    chaotic time series corresponding to the given fractal dimension?  
>    ........

>     If anyone can give me any guidance at all on this problem, I would greatly
>     appreciate it.  Also, any reference to literature that may help me would
>     be nice.

I cannot help you directly but have a look at the following paper:
R. Szeliski and D. Terzopoulos, "From Splines to Fractals", Proceedings of
SIGGRAPH'89.

It relates the energy of a (physical) spline to fractal statistics via a
Gibbs distribution (p(x) = exp(-E(x)/T)).

good luck,
Jos
Newsgroups: comp.doc.reports,sci.fractals
From: dieter@cs.kuleuven.ac.be (Dieter van Melkebeek)
Subject: reference request
Organization: Dept. Computerwetenschappen K.U.Leuven
Date: Fri, 13 Nov 1992 12:40:29 GMT



   Hi,

For my thesis, I am looking for next reference : 

      Digital image compression with two-dimensional affine 
      fractal interpolation functions
      S.A. Hollatz
      Technical Report 91 - 2
      University of Minnesota-Duluth
      Department of Mathematics and Statistics

Also, I 'd like to have contact with the Naval Ocean Systems Center
(NOSC) in San Diego.

Is there anybody who can help me ?

                   
                                         Kris Van Baelen


Newsgroups: sci.fractals
From: modus@gagme.chi.il.us (Patrick M. Kane)
Subject: Newton's Method
Originator: modus@gagme
Organization: Gagme Public Access UNIX, Chicago, Illinois.
Date: Sun, 8 Nov 1992 22:13:26 GMT

I recently read the book FRACTAL PROGRAMMING IN PASCAL and have a question
relating to the generation of Newton's Method fractals.  The following code
fragment iterates the equation z^3-1=0 :
xsquare= x * x
ysquare = y * y
denom = 3 * ((xsquare - ysquare) * (xsquare - yswaure) - 4 * xsquare *
ysquare)
IF denom = 0 then denom = 0.0000001
x = (2/3) * x + (xsquare - ysquare) / denom
y = (2/3) * y - (2 * x * y) / denom

This does, of course, work beautifully.  However, with my high school calculus
skills, I am unable to understand WHY.  Could someone please e-mail or post a
step by step explanation of each part of the above fragment?  Any help is
appreciated.

Patrick Kane
From: obry@flash.bellcore.com (Pascal Obry)
Newsgroups: sci.fractals
Subject: xfractint
Date: 6 Nov 92 22:15:32 GMT
Distribution: sci.fractals
Organization: /u/obry/.organization


Hello,

I'am unable to use the batch mode with xfractint-1.07.
Is it a known bug ? if not, could someone give me an example on how to use it ?
Maybe I use it wrong, but I don't think so, since I read carefully the manual.

Thanks,
Pascal.
--

-------------------------------------------------------------------------------
--  Pascal OBRY								     --
--  Room 2D-337				e_mail : obry@bellcore.com  	     --
--  Bellcore								     --
--  445 South Street			voice : 1 - 201 829 4039	     --
--  Post Office Box 1910						     --
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  `` inheritance is surely a good answer, but who knows the question ? ''
Newsgroups: sci.fractals
From: yavuz@bnr.ca (Yavuz Onder)
Subject: (x)fractint authors please read
Organization: Bell-Northern Research, Ottawa, Canada
Date: Thu, 12 Nov 1992 18:21:16 GMT



I am trying to print black and white postscript in device resolution,
and have a few problems/questions:

1. my postscript image comes out with 00 and FB as gray levels, I
would like the latter to be FF so that output has white instead of a
pattern of dots for the very light gray FB represents. How can I do
this?  What is the array "convert" into which a linear combination of
"dacbox" entries are put, when colorps=no is specified, why 00 and
FF are not used as the only "colors"? (also see the (3) below). Why
"convert" is filled differently based on compression usage?

2. scaling of the image is defective: when I specify epsf=0
printer=psl/300 the page gets filled by a distorted picture. instead
of using the part of page for a picture of correct aspect. When i
tried epsf=1 and psl it could fit only a small part of the picture,
and ignored the landscape spec. The same scaling factor for both
coordinates should be used to keep the image proportions correct. To
cater for the need of forcing the use of the finest resolution the
device can provide a double scaling just before the "image" is a good
idea e.g. "72 300 scale 2048 1536 scale" for the case of a 300 dpi
printer printing a 2048x1536 image. Note that the first scaling is
from postscript default (always 72) to current resolution whether
fractint default or user specified. Forcing the device resolution
should be tied to a user specified option of course. Which one is
appropriate (or a new one?)  you guys think?

3. when epsf is not specified, even if the PS/PSL is selected as the
printer type,a *.prn file is generated, whereas epsf=0 with everything
else the same, a *.eps file  is output. Is this a bug or do I have a
misunderstanding of the options involved. I think a little more
explanation of epsf and its interaction with other postscript related
parameters would be helpful.

4. i think imagemask should be used instead of image when device
resolution is specified.

I can suggest fixes for last three as I have already corrected them on
*.eps files and tried successfully, but the first one seems little
more complex.  for which I need your advice.

Thanks in advance for responses...

--
Yavuz Onder     |  Bell-Northern Research Ltd.    | My opinions aren't
(613)-763-2294  |  P.O. Box 3511 Station C        | necessarily BNR's,
yavuz@bnr.ca    |  Ottawa, Ont. CANADA  K1Y 4H7   | or vice versa.
From: gathe@ul.ie
Newsgroups: sci.fractals
Subject: Gif to postscript
Date: 4 Nov 92 19:41:01 GMT
Organization: University of Limerick, Ireland

Hello,
      I recently got FRACTINT and have been trying out some of its wonderful
features. I have managed to generate .gif files of the images, but when I
use my giftops coverter, it complains about the GIF version being 89A
(rather than 87A?). Do earlier versions of FRACTINT have a different
gif type, or does someone know where I can get an appropriate giftops
converter for FRACTINT output. Please e-mail me at gathe@ul.ie
Thanks,
       Eugene Gath
Newsgroups: sci.fractals
From: sassoj@rs6416.ecs.rpi.edu (John J. Sasso Jr.)
Subject: Interpolation & Chaotic TS
Organization: Rensselaer Polytechnic Institute, Troy NY
Date: Thu, 5 Nov 1992 14:49:30 GMT


    Given a chaotic time series with a fractal dimension, does anyone know of
    any theory or whatever which relates splines to the interpolation of the
    chaotic time series corresponding to the given fractal dimension?  For
    example, if I have a signal that can be best interpolated by cubic splines,
    then that is what I would use (using a linear or quadratic spline would not
    do so well).  Now, given a chaotic time series (perhaps one similar to that
    of Brownian motion), it would seem that you cannot interpolate it with any
    spline of some order, or you need a very high order spline in order to 
    interpolate it accurately.  This may sound crazy, but would it be that you
    would need a spline of some fractional order (in relation to the fractal
    dimension of the time series) in order to do an accurate interpolation?  Or,
    would the spline needed have to have fractal properties itself (a fractal
    interpolating a fractal, so to speak.  I got this idea from Barnsley's IFS
    where a base fractal is used to interpolate a fractal image).

     If anyone can give me any guidance at all on this problem, I would greatly
     appreciate it.  Also, any reference to literature that may help me would
     be nice.

                          John

Newsgroups: sci.fractals
From: psm3@cunixa.cc.columbia.edu (Perrin S Meyer)
Subject: Need C source for fractal modeling
Organization: Columbia University
Date: Thu, 5 Nov 1992 07:54:09 GMT


Does anyone know where I can get C source code that implements the 
fractal modeling of time-series data?

Thanks in advance.

Perrin Meyer
psm3@cunixa.cc.columbia.edu
From: bert.tyler@satalink.com (Bert Tyler) 
Newsgroups: sci.fractals
Subject: Can Resolution in Fractin
Date: 9 Nov 92 21:34:00 GMT
Distribution: world
Organization: Datamax/Satalink Connection * Ivyland, PA (215) 443-9434
Reply-To: bert.tyler@satalink.com (Bert Tyler) 

JN>I'm in the process of producing high quality fractal prints/posters using
JN>Fractint v17.2.  To maintain resolution for large posters, I'd like to exceed
JN>the maximum resolution of 2048x2048 in Disk/RAM Mode.
JN>Can this be done by a simple tweaking of the source code, or is it a much more
JN>involved programming job to do this?

For the current versions of Fractint (and Winfract), it would be a massive
job.  Lots of equivalenced arrays all squashed together into a single
64K segment space.

Xfract (and possibly the OS/2 2.x-specific version of PMfract) might well
be a different story.

                   Bert Tyler   (bert.tyler@satalink.com)
---
 . DeLuxe./386 1.25 #343sa . Did you expect mere proof to sway my opinion?
                               
Newsgroups: sci.fractals