| Requirements engineering is an activity
of software engineering. Using requirements engineering
techniques, we define the requirements of the system under
development. Requirements engineering consists of two
main activities: requirements elicitation (which
produces a specification of the system that the customer
understands) and analysis (which produces a models that
software developers unambiguously understand.)
We will use scenario-based
requirements elicitation. With scenario-based
requirements elicitation, we map a system problem statement
into a system specification that we represent as a set of
actors and use cases. Actors represent external
entities that interact with the system. The first step
of requirements elicitation is the identification of
actors.
Once the actors are identified, we
determine the functionality that need be accessible to each
actor by identifying scenarios. A scenario is a description of
a system use in terms of a series of interactions between the
system and the user. We work with the customer to get a
complete set of scenarios, which enumerate in natural language
using customer terminology. A complete set of scenarios
will describe everything the system is intended to do. Next,
developers formalize scenarios into use cases. A
scenario is an instance of a use case. A use case
specifies all possible scenarios for a given piece of
functionality. A use case is initiated by an
actor.
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Use Case Flow of Events Example:
Intersection
Bank
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