You have identified the use cases for the system or application
and captured them in a use case model. The next step in the development process
is to build on the use case model by describing the structure of the system.
In this phase, you analyze the application domain to discover the domain requirements
of the system and create a high-level object model that describes how the
system will be logically constructed. You can use class diagrams and sequence
diagrams to capture the logical implementation of the functional requirements
that you described in the use case model.