_ Recording reminders to self
_ Recording activities performed to demonstrate accountability for actions
_ Recording requests for someone else to do something
_ Recording direct observations or measures to monitor the condition of a
subject of interest
_ Record the outcome of activities that affect the availability of resources,
such as money in an account, time spent by a specific human resource,
amount of time a specific piece of equipment was used
_ Record the authorization to do something or acknowledge a decision
_ Calculate new measures or summaries from information already available
Using diagrams during the requirements definition phase and recording
the resulting pictures in information system tools that support requirements
definition helps to maintain a clear linking of requirements to delivered information
systems over time. As information systems are added and changed,
the impact on other information systems or related activities can be predicted.
Integration of the specific diagrams and the accompanying detailed
information into requirements definition tools ensures that each perspective
is adequately represented and that all the details are recorded that make up
the accurate specification of just what an information system is supposed to
do and how it is integrated into daily activities. Figure 13.1 represents how
people with different viewpoints would view a complex information system.
If each circle represents the scope of interest of a different perspective, it is
easy to see that complete understanding is impossible by considering only a
single perspective. Effective information systems need to be built from specifications
that integrate the multiple perspectives into a congruent whole.
The ability to view different aspects individually, however, ensures that each
perspective is accommodated and allows the appropriate people to validate
that their needs have been met. The requirement definition tools also help
identify how the activities of people and the corresponding roles and responsibilities
along with the organizational policies and procedures must
be adjusted to make the whole work environment more effective as new
information systems are implemented.
The following diagrams are often used during the requirements definition
phase. There are 13 types of diagram available in UML, each of which adds
clarity to some aspect of the requirements definition or component analysis,
design, and deployment management.