Modularity
Model at one level of abstraction: flat
Model with interacting modules that can be understood
separately: modular
Model with modules that are (recursively) decomposed
into modules: hierarchical
Example: Planning a trip from here to a see the Mona
Lisa in Paris.
Flat representations are adequate for simple systems.
Complex biological systems, computer systems,
organizations are all hierarchical
A at description is either continuous or discrete.
Hierarchical reasoning is often a hybrid of continuous and
discrete.