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Chapter 5 Exercises 143

Structural models show the organization and architecture of a system. Class diagrams are
used to define the static structure of classes in a system and their associations.
Behavioral models are used to describe the dynamic behavior of an executing system. This
can be modeled from the perspective of the data processed by the system or by the events
that stimulate responses from a system.
Activity diagrams may be used to model the processing of data, where each activity
represents one process step.
State diagrams are used to model a system’s behavior in response to internal or external
events.
Model-driven engineering is an approach to software development in which a system is
represented as a set of models that can be automatically transformed to executable code.

FURTHER RE ADING

Requirements Analysis and System Design. This book focuses on information systems analysis
and discusses how different UML models can be used in the analysis process. (L. Maciaszek,
Addison-Wesley, 2001.)
MDA Distilled: Principles of Model-driven Architecture .This is a concise and accessible
introduction to the MDA method. It is written by enthusiasts so the book says very little about
possible problems with this approach. (S. J. Mellor, K. Scott and D. Weise, Addison-Wesley, 2004.)

Using UML: Software Engineering with Objects and Components, 2nd ed. A short, readable
introduction to the use of the UML in system specification and design. This book is excellent for
learning and understanding the UML, although it is not a full description of the notation.
(P. Stevens with R. Pooley, Addison-Wesley, 2006.)

E XERCISES

5.1. Explain why it is important to model the context of a system that is being developed. Give
two examples of possible errors that could arise if software engineers do not understand
the system context.
5.2. How might you use a model of a system that already exists? Explain why it is not always
necessary for such a system model to be complete and correct. Would the same be true if
you were developing a model of a new system?