Re: Separation of representations of the ontology

[M Lang / S Railsback]

> Fred Wan wrote:

Hi Fred:

We have dealt with some of these issues in our trout model. In fact, I
was going to post a message that we just remodeled our web site and
updated it with latest models, reports & pubs:

http://math.humboldt.edu/~simsys/

In particular, if you go to the "Products" page on our site you will now
find a report documenting the formulation of our trout model.

We have (in some versions) multiple species of trout competing in a
size-based hierarchy for the available food in a habitat cell- the
biggest fish gets to eat all it wants, the smaller fish get what is left
over. The fact that we use habitat cells (little discrete boxes of
homogeneous space) instead of a continuous space makes this a lot
simpler.

> -Communication between agents, especially when it is non-directed. For
> instance, agents may send out alarms when they see a predator, but this
> signal is non-directional and the sender has no way of knowing which agent
> picks it up. In this case the physics of the world determine how far the
> signal is carried. Should this be represented separately? Perhaps like a
> FoodSpace, but instead of food the representations are soundwaves or photons
> that move across the 2d grid?

Wouldn't it be nice if the Swarm grid object had a method
-getObjectsWithinThisDistance: ?
Then if an agent sends out a signal, you could identify which other
agents detect it. 
(We and I'm sure others have written such a method by hand.)
 
> -Obstacles in the world. On top of hunters, prey and communication there may
> also be physical obstacles or other kinds of structure in the world that
> obstructs movement of entities and phenomena.

We put waterfalls ("barriers") in our trout model- a fish can go
downstream over a barrier but it can't get back up. We therefore assume
that the fish has no knowledge of what lies across the barrier, since it
could not have gone exploring there. The interesting question is then
when/why would a fish decide to go over the waterfall- our hypothesis is
that they take the plunge only if then anticipate that staying where
they are is likely to have bad future consequences. There is at least
one lab study showing that if you take the food away from fish, they
will take such a plunge into the unknown within a few days (which is
long before actual starvation sets in).

Steve
-- 
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Lang, Railsback & Assoc.
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