Re: [Swarm-Modelling] newbie question

[alex dinovitser]

--- "Marcus G. Daniels" <address@hidden> wrote:
> alex dinovitser wrote:
> 
> >It appears to me that development in the project has
> >slowed down if not stalled over the past 3 years. Is this true? if so, why?
> >  
> >
> Quite correct!   The reason is no funding.  The reason for no funding is 
> debatable, of course, but my take is that many people in serious 
> scientific circles feel that agent based modelling is a dodgy scientific 
> activity.  Too many free parameters, too many ways to make up nonsense 
> stories for why simulations did what they did, no general theoretical 
> way to know whether a given simulation configuration is the only way to 
> get from some set of initial conditions to a result or one of a family 
> of hundreds or millions of ways to get to a result.   This is assuming 
> that the authors of a given computer simulation (in Swarm or whatever) 
> come close to understanding what their program really does or even 
> understand what they intend it to do.

This suggests that perhaps the goals of the project are too ambitious? 
Simple discrete time-update simulation modelling tools such as GPSS/h and Siman
(part of ARENA) that I have used, have very restricred capability in terms of
agent behaviour, however, they have been useful tools for many decades in such
diverse areas as mine planning design, transport systems, queuing behaviour,
etc, etc. The basic purpose of these models is simply to find good numerical
solutions to relatively simple problems that do not have optimal analytical
solution. The simulation also feeds measurements (from calculations) into an
animation, which serves to verify the model operation, as well as a great prop
for board room presentations!


My main question regarding SWARM, is; How suitable is it for these less
ambitious applications where there is a small number of simple agents
(entities) and only a few types of agents, each with a fixed set of attributes
that get re-calculated during every interaction, with results fed to a simple
2D animation as the model runs???
In these applications, we are not looking for emergent behaviours, and indeed
big surprises are rare. We just want to model the real world to try out
different operating procedures/ scenarios to calculate such simple attributes
as cost, contamination, delay time, etc.
There is no question here about us knowing what we want the model to actually
do, parts of it could be done using a spreadsheet. A simulation modelling tool,
however, would allow us to more easily expand the model as more data becomes
available, introducing more entities as the modelled space increases, and drive
some sort of animation engine.
Would SWARM be a good choice?


> 
> Even if one limits the goal of a simulation to be illustrative of 
> dynamics that challenge popular analytical techniques or assumptions of 
> the possible, there is still the challenge to convince some people that 
> the programs that generate these phenomena are correct and consistent 
> enough to bother with.  Norms are needed in these academic communities 
> for validation and verification and both are complicated tasks.  That 
> kind of activity can be an unwelcome distraction to advocates and 
> skeptics alike.

In that case, why are there all these new (apparently) copycat closed-source
software projects now??
Here's an example....
http://www.dis.anl.gov/DIAS/

What do you think about it?


regards,

Alex Dinovitser.




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