Re: Walls and Communication

[dsumpter]

>Ahh, so the walls are big enough to contain more than one bee!
>Can the clusters of bees change members?  And do you have more
>than one cluster in your sims?  Final question (then I'll leave
>you alone, I promise [grin]), do the walls move or change shape?

So, in reality bees will normally only cluster with other bees of the
same hive (indicated by a chemical thing). I'm just really looking at
one hive. I scatter the artificial bees randomly and watch how they
cluster as the ambient temperature drops. Depending on various
parameters they'll cluster into one large group or several smaller
ones. Larger groups will survive longer than smaller groups. Sometimes
these small clusters do swap members but that normally leads to one
cluster swallowing another.

As for walls: Just now all the bees are trapped in one big square (a
hive). Unfortunately, not anywhere near as interesting as the sort of
thing you were envisaging. At some point I may be looking at bee
swarming (appropriately enough) and this will involve bees settling on
a branch which could be represented as a more complicated wall structure. 

>One of the issues we hope Swarm will help us deal with is the
>preservation of the properties of swarms in spite of the turn
>over in membership.  And if you've already got members of a
>swarm surrounded by a membrane that's permeable to those members,
>then you've got half of it in place.  A bee would move out of 
>a cluster/swarm, through the membrane into space (where it would
>either be a singleton member of the owner swarm or some special
>transient swarm that contains only an individual bee), and then,
>possibly, move into another swarm.

My thermoregulation model is just a get to grips with modelling task
with which I hope to model the spread of parasites in bee hives. One
interest is the collapse of single hives but also interesting is the
way bees in `unhappy' hives attempt to join other `happy' hives...thus
causing the parasite to spread quickly. I think this model would be
down those lines.

>But, this will definitely be different from your Wall in that 
>it will only surround one agent and it probably won't be passive.
>Hmm...It sure would make things easier if it were passive, though,
>wouldn't it?  All you do is decrease the amount of heat that
>passes through the wall?  It works the same in both directions,
>right?

All cells in the simulation grid take new values by the diffusion
equation:

NewTemp = OldTemp + InsulationFactor * (Neighbourhood Differences).

InsulationFactor is 1.0 for no object in the cell and some value less 
than 1.0 if their is an object (e.g. a wall) in the cell.

This leads to a reduction in heat transfer from one side of the wall
to the other.

------------------------------

You obviously have put a lot more thought into `self' than I
have...its not always that healthy you know........ 
Actually, one thing people always comment on when they see me press
the stop button after a simulation is how I happily kill all my
bees. I'm sure thats irrelevant but interestingly irrelevant.

David.