Re: calibration

[alan penn]

To throw in twopenny worth,

>> Perhaps you are talking about ecosystems from your simulation-oriented
>> point of view, as the word 'calibrate' indicates.
>
>Perhaps I am.
>
>> I think that a complex
>> system like an ecosystem cannot be modeled with some large FSM  or even
>> with a set of stochastic equations (except in the short-term): in an
>> ecosystem there is probably no unique latent 'model' to be discovered,
>> against which we could compare some data and make adjustments. Instead
>> there probably exists many possible modes, with the system unpredictably
>> switching from time to time to one or another.
>
>I am not sure that we could argue this one way or the other. I see
>no reason why a model could not be developed. When you say "many
>possible modes", this can easily be modeled by stepping up a level
>of abstraction so that the modes are modeled as well.
>
>> The first thing to do could be to try to recognize these modes. 
>
>Yes, as part of our systems identification process.
>
>> Because
>> switching is unpredictable (ecosystems seem to exhibit self-organized
>> critical modes), it makes no sense to try to 'calibrate' the whole system,
>> in the same manner simulation engineers calibrate a model of a factory or a
>> flexible workshop.

Try this one. Perhaps the 'calibration' is in the environment. What I mean
by this is that the configuration of the spatial environment inhabited by
moving and stationary individuals in the ecosystem could in principle carry
with it the 'model' (or several models) inherent in patterns of
co-occupancy of space. Think, for example, about human systems like
buildings or cities. Modern societies in Levi-Strauss 'statistical' sense,
consist in a set of probabilities describing regularities - eg: within race
marriages are more likely than inter racial marriages, but there is no rule
system prohibiting them as there might have been in more primitive
'mechanical' social forms. How could such probabilistic regularities emerge
and be maintained? One possibility is that they arise through the way that
spatial configuration and movement of individuals bring different groups
into contact. 

Most geographers treat space as 'map space' in that it is essentially open
and homogeneous in all directions, but as soon as you start to think about
the space through which we actually move, within and between buildings,
then the probabilities of co-presence become significantly structured. If
you then map onto this sort of spatial configuration the locations of
particular individual's or social groups' facilities, the places they must
visit regularly in their daily lives, then you can create a structured, but
essentially probabilitic set of interfaces. You could envisage a single
spatial configuration coupled to multiple sets of group's 'programmes'
giving rise to just the sort of latent model with multiple realisations
that complex things like societies require.

A final point - perhaps it is the mapping of spatial configuration and
cultural 'programmes' - which are actually constructed by people after all
- that provides the locus for reproduction of the regularities that we call
social??

Alan Penn

________________________________________________
Alan Penn
The Bartlett School of Architecture and Planning
Philips House  (Room 335)
University College London, Gower Street, London WC1E 6BT
tel. (+44) (0)171 387 7050 ext 5919   fax. (+44) (0)171 916 1887
email. address@hidden
www.   http://doric.bart.ucl.ac.uk/web/Pangea/index.html
________________________________________________




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