So today we're going to talk about one more other element that you should
consider when designing the agents for your agent based model.
We've eluded to this before but you have to choose the level at which you're going
to actually create the agents themselves.
Now it doesn't even have to be the same level for every agent type in the model
but we're get into that in a little bit.
As I mentioned before, an agent doesn't necessarily have to be an individual or
an employee or a person on the street or something like that.
It could be a corporation. It could be an organization. It could be a cell.
It could be whatever, right?
So here, just as an illustration, I have two different models created in the
medical field. So on the left, we have this tumor model. A model where you're
looking at cancer. As you can see, maybe it's not completely obvious, but each of
these little dots represents a cell. So the agents in this model are cells.
Over here, we have an AIDS model. A model of AIDS transmission in a community or a
society. In this case, each of the little agents is represented by a human being,
a person. It's interesting to me. We have two different models, both kind of disease
related phenomenon. But in one case we have the model being done at the person
level and in the other case at the cellular level.
Why would you choose these two different levels?
Well the main reason is because of the question they were interested in answering.
In the tumor model, they're essentially looking at how different treatments can
affect tumor growth. In the HIV model, the AIDS model, they're looking at how HIV
propagation happens throughout an entire community.
They're very different kinds of goals and in each case they chose the level of an
agent to correspond to the research question they were interested in asking.
So that's why you get these two different level choices.
By the way, both of these models are available in the NetLogo models library.
So one other thing we should talk about is...we've talked about agents but there
are a couple of special words that are often thrown around in the agent based
modelling literature that relate to different types of agents that aren't your
traditional formal agents.
One word that is thrown around is a meta- agent. A meta-agent is an agent that is
composed of other agents. For instance, you could imagine you have a business and
you have the business represented as an agent interacting with other businesses.
But then maybe within that business you have different departments and those
different departments take different actions and those different actions are
part of the business organization but the business is not just the composition of
those different departments.
You could even go lower than that. Within the departments you could have
employees and those employees could be agents.