ABSTRACT
Conceptually, requirements are requested system’s fea-
tures, often described as properties that help a system fulfill
its purpose. Requirements are the product of the require-
ments elicitation process, a central part of requirements
engineering (cf. Requirements Engineering: Principles
and Practice, p. 949) intended to determine the needs of
the system stakeholders. In that context, functional require-
ments capture the intended behavior of the system in ques-
tion. This behavior may be expressed as services, tasks, or
functions a system is required to perform. Here, one of the
most important goals of requirements engineering is to
help system stakeholders understand the behavior of the
system in question. Among the different techniques for
capturing system behavior, use cases are of major impor-
tance because their approach ensures expressing require-
ments in a way understandable to both users and
developers.
