🚀 go-pugleaf

Volume: 7, Issue: 2, Mon Jan  9 09:12:57 EST 1989

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| TODAY'S TOPICS |
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(1) Genetic Algorithms
(2) Supercomputing/Numerical Aerodynamics Simulation Division
(3) Looking for BNF Grammar for SPICE
(4) Electronic Mail Address for SIMULA

* Moderator: Paul Fishwick, Univ. of Florida
* Send topical mail to: simulation@uflorida.cis.ufl.edu
* Archives available via FTP to bikini.cis.ufl.edu, login as
  'anonymous', use your last name as the password, change
  directory to pub/simdigest.



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Date: Mon, 19 Dec 88 09:33:25 EST
From: Paul Fishwick <fishwick@fish.cis.ufl.edu>
To: simulation@ufl.edu



[[FROM EDITOR: taken from news group 'bionet.molbio.evolution' -paf]]


Newsgroups: bionet.molbio.evolution
Subject: Simulating Evolution
Date: 17 Dec 88 22:52:00 GMT
References: <4806@phoenix.Princeton.EDU> <4029b61d.ffb5@bumper.engin.umich.edu> <7034@venera.isi.edu>
Reply-To: offutt@caen.engin.umich.edu (daniel m offutt)
Organization: caen

In article <7034@venera.isi.edu> smoliar@vaxa.isi.edu.UUCP (Stephen Smoliar) writes:
>The characterization of genetic algorithms may have reversed the cart and the
>horse.  Genetic algorithms may be said to have been inspired by chromosomal
>behavior, but I think it would be an exaggeration to call them a simulation,
>of any organic situation.  

Genetic algorithms are not just motivated by evolution, they are
simulations of evolution including:

1.  A population of linear or circular strands of DNA each modeled using
    a two-letter alphabet,
2.  An environment modeled as a computable function which determines
    fitness of a chromosome,
3.  Fitness-based reproduction of chromosomes (offspring),
4.  Crossing over of pairs of chromosomes producing recombinants,
5.  Point mutation,
6.  Inversion (in some models),
7.  Punctuation marking sites of possible crossing over (in some models),
8.  Recessive and dominant alleles (in some models),
9.  Speciation (in some models),
10. Semi-isolated subpopulations (in some models),
11. Mate-selection procedures (in some models),
12. A temporal ordering and causal connectedness among these events
    which correspends to the modeled events in nature: successive
    generations of creation, testing, recombination, reproduction,
    and finally deletion from the population.
                    
The world is too complex for any computer simulation to capture every
aspect of evolution, or any other physical process. Consequently there
are aspects of evolution not simulated (yet) in genetic algorithms,
including:

1.  Fertilization,
2.  Spontaneous abortion,
3.  Multiple chromosomes in one genotype,
4.  Any of the idiosyncrasies of the generation of sex cells aside
    from crossing over.
5.  Homologous pairs.
6.  Any of the codon sequences found in DNA, aside from those coding
    for sites of possible crossing over.
7.  Transcription.
8.  Protein synthesis.
9.  etc., etc.

My point again is that the algorithm was copied from nature, not
invented by, say, a clever operations researcher.  (The formal theory
of genetic algorithms is another matter.  Holland (1975,1976) has
proven a generalization of Fisher's (1930) classic result which
is not restricted to alleles, but holds for all subsets of alleles
within individual chromosomes.  Genetic algorithms derive largely
from this genetic search theory (GST) which falls within the field
of mathematical genetics.)  A "no-frills" genetic algorithm, with
the basic allele-set ranking capabilities that make GA's effective
function optimizers, can be implemented in one page of C code.
The fundamental algorithm is simple enough that it is quite plausible
that it was discovered (by nature) via a much weaker pure-random
search process.

The observed efficiency of genetic algorithms at locating ever-better
local optima on a wide variety of complex performance surfaces,
without becoming trapped on a local optimum anywhere,
counts as evidence that if it were applied to optimizing performance
measures defined by natural environments, it would be able to
locate quite complex stable physical systems such as plants and animals.
So perhaps, given the similarity of the algorithm to the natural
evolutionary process, this is what has actually happened.

======================================================================
Dan Offutt                                 offutt@caen.engin.umich.edu





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To: ames!comp-simulation@ames.arc.nasa.gov
Path: eos!eugene
From: eos!eugene@eos.arc.nasa.gov (Eugene Miya)
Newsgroups: comp.simulation
Subject: Supercomputing: Experience Preferred But Not Essential (Announcement of Opportunity)
Keywords: university/college graduating students
Date: 5 Jan 89 07:14:31 GMT
Sender: eos!eugene@eos.arc.nasa.gov
Reply-To: eos!eugene@eos.arc.nasa.gov (Eugene Miya)
Distribution: usa
Organization: NASA Ames Research Center, Calif.


Are you a savvy tiger?

A Special Announcement of Opportunity (AO)

Numerical Aerodynamic Simulation Systems Division
NASA Ames Research Center

The Numerical Aerodynamic Simulation (NAS) Systems Division is seeking
new, recent, "fresh-out," graduates for challenging positions in large-scale
computer systems research, development, and operational support at
the NASA Ames Research Center located on Moffett Field, CA
[southern-most tip of San Francisco Bay in the Santa Clara Valley].

The NAS Facility houses one of the world's largest and most advanced
supercomputer systems, used by a nationwide user community for
solving highly complex problems in fluid dynamics, aeronautics, space,
and other scientific disciplines.  The System includes a CRAY Y-MP*,
a CRAY-2, a Thinking Machine's Connection Machine-2, dual Amdahl 5880's,
four VAX 11/780s, over 30 Silicon Graphics Iris and SUN workstations
interconnected with local area networks ranging in speed 10 to 800 Mhz.
The user visible operating system is UNIX with TCP/IP-based networking
extensions.  [Everything!]

Systems research, development, and computational service opportunities
exist in the following areas:
	1) Supercomputers
	2) Mass Storage Systems
	3) High Performance Scientific Workstations
	4) High Performance Data Networks
	5) Long Haul Communications
	6) Mini-supercomputers

Future developments will involve NeXT machines, Ardent Titan and Stellar
graphical superworkstations, and other flavors of state of the art
high technology.

These positions require at least a Bachelor's degree [or more] in
computer science, engineering, or one of the physical sciences.
Knowledge of the UNIX operating system and the DoD Internet Protocols
is highly desireable.  This is an excellent entry opportunity for the
young and young-at-heart.

NASA (The National Aeronautics and Space Administration) is the Nation's
civilian space Agency.  The NASA Ames Research Center is an
Equal Opportunity Employer.
US Citizenship is required.  Security clearance is not required.
Send resumes to:

	Mr. Bruce Blaylock
	Chief, NAS Systems Development Branch
	M/S 258-5
	NASA Ames Research Center
	Moffett Field, CA 94035
	blaylock@prandtl.nas.nasa.gov or
	ames!prandtl!blaylock
	TeX and troff okay.
	
*Trademarks:
CRAY Y-MP, CRAY-2 are trademarks of Cray Research Inc.
Connection Machine-2 is a trademark of Thinking Machines Corp.
UNIX is a trademark of AT&T Bell Laboratories.
VAX is a trademark of Digital Equipment Corporation.
Iris is a trademark of Silicon Graphics Inc.
SUN is a trademark of SUN Microsystems Inc.

Send specific questions to me.

  eugene miya, NASA Ames Research Center, eugene@aurora.arc.nasa.gov
  resident cynic at the Rock of Ages Home for Retired Hackers:
  "Mailers?! HA!", "If my mail does not reach you, please accept my apology."
  {uunet,hplabs,ncar,decwrl,allegra,tektronix}!ames!aurora!eugene



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To: comp-simulation@rutgers.edu
Path: hplabs!hp-ses!hpcuhb!najmi
From: hplabs!najmi@hpcuhb.hp.com (Farrukh Najmi)
Newsgroups: comp.simulation
Subject: Looking for BNF for SPICE.
Date: 6 Jan 89 17:00:45 GMT
Organization: Hewlett Packard, Cupertino


I am looking for a BNF description of HSPICE
or spice syntax. If any one has a yacc parser
and lex scanner for any variation of spice I
would love to have it. 

Thanks in advance. Farrukh Najmi.



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Sender: "Leonard_S._Li.ESAE"@Xerox.COM
Date: 6 Jan 89 11:30:56 PST (Friday)
Subject: Electronic mail address for Simula a.s.?
From: LLi.ESAE@Xerox.COM
To: Simulation@ufl.EDU
Cc: LLi.ESAE@Xerox.COM


We are interested in the capabilities and the cost of Simula.  The 10/88
issue of "Simulation" lists the address of the organization supporting
Simula as:

Simula a.s.
Postbox 4403 Torshov
N-0402 Oslo 4
Norway
(472) 156710

Does anyone know if they have an electronic mail address?  Please also tell
us if they have an agent/dealer in the U.S.  Thanks.

Leonard Li
Xerox
El Segundo, CA, U.S.A.



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