________________________________
From: Jim Doran [mailto:[log in to unmask]]
Sent: Mon 11/08/2008 20:47
To: Doran, James E
Subject: Re: [SIMSOC] Whendo big models give different results from small ones?
I don't believe that there is any general answer to Nigel's question. And
the conditional answers are complex and hard to think thru. This is why I
and some others have tried experimenting with computer algorithms that can
search for and find the most effective level of granularity/abstraction at
which to
use an initially detailed model (assuming the model is to be used
repeatedly).
This may include aggregating many agents into one.
But, of course, it's difficult eg see my EPOS06 paper.
Jim
Emeritus Professor J E Doran
Department of Computing and Electronic Systems
University of Essex
Colchester CO4 3SQ
United Kingdom
http://www.essex.ac.uk/dces/people/doran.aspx
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From: News and discussion about computer simulation in the social sciences
on behalf of Nigel Gilbert
Sent: Sun 10/08/2008 22:17
To: [log in to unmask]
Subject: [SIMSOC] Whendo big models give different results from small ones?
In what circumstances might it be necessary to implement agent-based models
of thousands or millions of agents, rather than the more typical tens or
hundreds? Do you know of any examples where scaling up the model (in terms
of the number of agents) gives qualitatively different results? Do you know
of any literature that addresses this issue?
I'd be very interested to hear of any suggestions.
Thank you,
Nigel
_______________________________________________________________________
Professor Nigel Gilbert, Editor, Journal of Artificial Societies and
Social Simulation, <http://www.soc.surrey.ac.uk/JASSS/>
Centre for Research on Social Simulation (CRESS)
Department of Sociology, University of Surrey, Guildford, UK.
Tel:+44 1483 689173 [log in to unmask]
<http://cress.soc.surrey.ac.uk/>
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