[FRIAM] A billion agents

[Raymond Parks]

Douglas Roberts wrote:
> Another way to answer this is, "No, it will not be self fulfilling if 
> there is an appropriate experimental design for using 
> stochastically-generated input parameters for agents in an ABM system."  
> EpiSims uses stochastically generated disease parameters to characterize 
> both the disease agents and the individual person responses to disease. 
> When the EpiSims runs are made there are additional stochastic processes 
> that influence population mixing patterns, with the results being 
> statistically valid, and non-self-fulfiling.
> 
> --Doug
> -- 
> Doug Roberts, RTI International
> droberts at rti.org <mailto:droberts at rti.org>
> doug at parrot-farm.net <mailto:doug at parrot-farm.net>
> 505-455-7333 - Office
> 505-670-8195 - Cell
> 
> On 10/9/06, *Marcus G. Daniels* <mgd at santafe.edu 
> <mailto:mgd at santafe.edu>> wrote:
> 
>     Being distributions, the parameters (the mixing ratios of different
>     kinds of agent behaviors) will have random peturbations around typical
>     values and in a large or long enough run you'll witness the consequences
>     of how this bias might play out at a global level.
> 
>     The bigger the computers, the wider variances of agent mixes that can be
>     measured.

   What I'm hearing is that you-all (or at least Doug) use statistically 
valid distributions to program the behaviour of your agents.  This seems 
reasonable for things that can be measured with certainty - patient 
response to disease, for example.  However, it seems to me that if you 
conduct a survey of a population sample concerning, say, political 
opinion or purchasing habits, you run the risk of bias in the survey 
being translated into bias in the ABM.

   Let me suggest an example close to my own heart.  I am interested in 
how people react to retail market price changes in electricity in future 
demand-response systems.  There are some data from existing 
demand-response systems but these function differently than newer 
systems.  What's more, the populations are geographically different from 
the target populations and they are much smaller.  We could survey 
customers to see if they would allow their heating and air-conditioning 
systems to respond to market prices.  The trouble with past surveys of 
this type is that utility customers tend to be more willing to sacrifice 
comfort in the abstract than in reality.  If one uses the PDF from the 
survey, then the results are far different than the PDF from the 
reality.  And, the reality only works for certain locales and climes.

-- 
Ray Parks                   rcparks at sandia.gov
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