Modeling of Dynamic Behaviors
Use Cases - Functional specification modeled at the real world level.
Sequence Charts - Interactions among class instances by invocations of
State Charts or State Machines - Graphical specifications for the states
of object instances and the events causing the transitions
among the states of the object instances. State machines are
specified at the class level and govern the behavior of all
State Charts are hierarchical state machines. That is: each
state may be a simple state or a state machine.