|
Where
|
|
one object
|
|
needs to act on
|
|
another.
|
|
|
Where
|
|
a
person
|
|
needs
to locate
|
|
information.
|
|
|
Where
|
|
an object
|
|
needs to be
|
|
located.
|
|
|
Where
|
|
software
|
|
needs
to control
|
|
a
process.
|
|
|
Where
|
|
a
process
|
|
needs
to react
|
|
to
an object.
|
|
|
Where
|
|
an
object
|
|
needs
to control
|
|
the
software.
|
|