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Alife Digest Number 029
ALIFE LIST: Artificial Life Research List Number 29 Monday, July 23rd 1990
ARTIFICIAL LIFE RESEARCH ELECTRONIC MAILING LIST
Maintained by the Indiana University Artificial Life Research Group
Contents:
Computational Metabolism pictures available on line (for Mac viewing)
TR announcement (ftp only)
----------------------------------------------------------------------
Date: Sat, 7 Jul 90 11:52:58 -0500
From: Marek Lugowski <marek@iuvax.cs.indiana.edu>
Subject: Computational Metabolism pictures available on line (for Mac viewing)
Hello. Below is the text of a readme file I just installed under anonymous
ftp on iuvax.cs.indiana.edu. It describes some interesting pix I'd love for
you to take a look at.
-- Marek
--- begin Readme
[this file resides in ~ftp/pub/marek/ComMet-images. ftp anonymously to
iuvax.cs.indiana.edu (129.79.254.192)]
Hi. The images here are 128x128 and each pixel is represented by a byte
that is ASCII and printable and renders as a nice color on the Macintosh.
They are examples of output of a Computational Metabolism (ComMet) model
of computation running with 5 colors of tiles, no state-switching in tiles,
only displacement. See C. Langton's _Artificial Life_ for ComMet description.
The easiest way I know to view them on a Macintosh is to get an application
program that reads in pixel maps. Image 1.19 is one. So is NCSA Image Tool
and NCSA Gelreader (! Commet is a fluid/colloid after all...).
Answer 128 and 128 for width and height in the prompt box of the OPEN
command of any of these three programs. Actualy, for Image 1.19 use
the IMPORT command instead.
You will be rewarded with spectacular color pix of running Computational
Metabolism started in the torus geometry and switched in midstream
into a borderd square at genneration 59,999. The rapid convergence at
62,000 is shown. What you are looking at is a 5-color flip-only (no
state changes) ComMet instance that ends up as a superposed square on
the background of a 4-square checkerboard. The "five" directory
contains runs with one of the 4 being much smaller and the "5deq"
directory contains a run with equal areas all around.
Notice the partial order emergent during the computation as the inital
horizontal dutch flag (5-color horizontal bands running full width) dissolves
into complete hash to reemerge as the 5th-on-background-of-4 pattern after
generation 59,999. It does so exceedingly swiftly and with interesting path.
Your comments, insights and suggestions are most welcome.
Marek Lugowski
Artificial Life Research Group
Indiana University
marek@cs.indiana.edu
7 July 1990, Lake Monroe, Indiana
------------------------------
Date: Thu, 19 Jul 90 22:24:00 PDT
From: schraudo%cs@ucsd.edu (Nici Schraudolph)
Subject: TR announcement (ftp only)
The following technical report is available via anonymous ftp from the
Artificial Life archive server:
--------
Dynamic Parameter Encoding for Genetic Algorithms
-------------------------------------------------
Nicol N. Schraudolph Richard K. Belew
The selection of fixed binary gene representations for real-valued
parameters of the phenotype required by Holland's genetic algorithm
(GA) forces either the sacrifice of representational precision for
efficiency of search or vice versa. Dynamic Parameter Encoding (DPE)
is a mechanism that avoids this dilemma by using convergence statistics
derived from the GA population to adaptively control the mapping from
fixed-length binary genes to real values. By reducing the length of
genes DPE causes the GA to focus its search on the interactions between
genes rather than the details of allele selection within individual
genes. DPE also highlights the general importance of the problem of
premature convergence in GAs, explored here through two convergence
models.
--------
To obtain a copy use the following procedure:
$ ftp iuvax.cs.indiana.edu % (or 129.79.254.192)
login: anonymous
password: <anything>
ftp> cd pub/alife/papers
ftp> binary
ftp> get schrau90-dpe.ps.Z
ftp> quit
$ uncompress schrau90-dpe.ps.Z
$ lpr schrau90-dpe.ps
--------
Hardcopies will be available shortly; I will send out another announcement
then. The DPE algorithm will be an option in the GENESIS 1.1ucsd GA simu-
lator, which should be ready for distribution soon - please hold back the
requests until you see 1.1ucsd announced on this list.
--------
Nici Schraudolph, C-014 nschraudolph@ucsd.edu
University of California, San Diego nschraudolph@ucsd.bitnet
La Jolla, CA 92093 ...!ucsd!nschraudolph
------------------------------
End of ALife Digest
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End of Alife Digest
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