Hogan and Warrenfeltz's four categories of skills that conceptually build upon each other:

INTRAPERSONAL: self-awareness, self-esteem, resiliency, and self control.

INTERPERSONAL: perspective-taking, empathy, and anticipating others' actions.

LEADERSHIP: recruiting, retaining, and motivating a team, persistence, and promoting a vision.

Describe operations to be performed on the objects

Certain operations are implicit from the object structure and need not be shown

Operations for accessing/modifying attributes values

One way of identifying operations is by modelling the messages that may be passed between the objects

You can derive an object model from...

Goal model

Use cases

Elicitation notes

Any RE model/notes/documents you currently have

Generally:

Nouns -> classes, attributes

Identify core classes

Construct the class structures defining the association between classes

Including class generalization structures

Define the attributes associated with each class

Attributes can be revealed by the analysis of the system requirements

Define the messages that may be passed between classes and determine the relevant operations for each class

Generalization is a relationship between classes where one class is the parent class of another (derived/child) sub-class

in o-o you know this as "inheritance"

The sub-class/child inherits the attributes and operations of super/parent class

A variant of aggregation which adds the property of existence dependency

Aggregation is a special case of association

The aggregate indicates a "whole-part" relation ship

o..1 - Zero or one

1..* - one or more

1..40 - one to forty

1 - exactly one

3, 5, 8 - exactly three, five or eight

* - zero or more