Saturday, January 30, 2010

[Yasmin_discussions] yasmin on line again= this is not a simulation


As you may have noticed our heated discussion
about simulation suddenly went quiet- the pleasure
of asynchronous communication= the system gave
us all time to think ! If you send a post that did not
get through please re-post !!

Personally I would like to bring in the science end
of simulation which has been pretty absent from this

Numeric simulations have introduced new ways of
making scientific hypotheses= particular in areas of
complex and non linear systems where it has been difficult
to frame hypotheses in the form of "compact" descriptions
that we associate with equations like E=MC2.

As pointed out by Katherine Hayles ( and others) such
simulations are confirmed through a process of retrodiction
rather than a process of prediction= climate change models
for instance are tested against historical data and the
predictions they are used to make always have large
uncertainties associated with the uncertainties in the
physical theories coded in the models as well as available
historical data. Such systems are also often unstable
(the butterfly effect).

It is also notoriously difficult to validate such large scale
digital simulations= in astronomical simulations of the
evolution of structure of the universe the scientific community
has generated a number of "test cases" which all simulations
are tested against to see if the simulations agree.

We had an interesting seminar with historian of science
patrick mccray at IMERA
<>Where we
discussed the impact of computer science on
the arts, humanities and the sciences and the area of
simulation was an area that emerges as a cross disciplinary
theme that allows new kinds of theory both in the humanities
and the sciences

some of this overlaps with the topic area that we will be
exploring at the NETSCI Leonardo Satellite Conference
on the Arts, Humanities and Complex Systems.
<>we will shortly be announcing the
speakers at this conference.
The science of complex systems introduces new laws that
are applicable in some situations of simulation of complex systems
(for instance the way that people cluster can be modeled in interesting

Understanding spatial connectivity
of individuals with non-uniform
population density
We construct a two-dimensional geometric graph connecting individuals placed
in space
within a given contact distance. The individuals are distributed using a
country's density of population.We observe that while large clusters (group
of individuals
connected) emerge within some regions, they are trapped in detached urban
areas owing
to the low population density of the regions bordering them. To understand
the emergence
of a giant cluster that connects the entire population, we compare the
empirical geometric
graph with the one generated by placing the same number of individuals
randomly in
space. We find that, for small contact distances, the empirical distribution
of population
dominates the growth of connected components, but no critical percolation
transition is
observed in contrast to the graph generated by a random distribution of
population. Our
results show that contact distances from real-world situations as for WIFI
and Bluetooth
connections drop in a zone where a fully connected cluster is not observed,
hinting that
human mobility must play a

I would be interested in other comments on how simulations are being used
across the sciences and humanities to generate new kinds of theories

Yasmin_discussions mailing list

Yasmin URL:

HOW TO SUBSCRIBE: click on the link to the list you wish to subscribe to. In the page that will appear ("info page"), enter e-mail address, name, and password in the fields found further down the page.

HOW TO UNSUBSCRIBE: on the info page, scroll all the way down and enter your e-mail address in the last field. Enter password if asked. Click on the unsubscribe button on the page that will appear ("options page").

HOW TO ENABLE / DISABLE DIGEST MODE: in the options page, find the "Set Digest Mode" option and set it to either on or off.