It's like The Sims (Maxis TM)---people,
their interactions, their world, and objects in the world are
represented. However, activities are modeled in Brahms
in more detail, beliefs and how they change are explicitly
modeled, and focus of attention (what people notice in
the world) is also simulated (based on what people think they
are doing). In particular, communications are modeled in
much more detail, plus the logistic interactions are represented
(e.g., you need to know a fax number for sending a fax; how do
you find out the fax number?). In the Brahms framework, how people
behave depends on their group memberships/identities. People
belonging to the same group behave similarly. Behaviors are "blends"
of all the groups to which the person belongs. Finally, the simulation
display allows finding out why simulated people did what
they did and how their behaviors influenced each other.
In Brahms, people are called agents. Each agent has
his/her own beliefs, which may be specified when the simulation
begins (at both the agent or group level). Agent behaviors are
specified by situation-action rules, called workframes.
A workframe has a logical precondition (beliefs required
for workframe to be activated), actions (primitive with
durations, communications, movement, etc.), and consequences
(changed beliefs or facts in the world).
A workframe's detectables specify what types of objects/attributes
the agent might observe in the world while doing the actions.
An activity is modeled as an organized collection of workframes
(e.g., alternative behaviors or steps in a procedure).
An optional end condition specifies how the activity might
be satisfied, impassed, or aborted.
Workframes that do not have actions and so do not take time are
called thoughtframes.
In the jargon of AI, each agent is essential a "knowledge-based
system"; the simulation engine coordinates the processing
of each agent's behaviors.
Objects, such as telephones, rovers, etc. are modeled similarly,
except they are organized into classes and do not have
thoughtframes.