Alife Digest Number 029

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Alife Digest

 · 10 months ago

 
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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