ns2 project in lakshadweep
ns2 project in lakshadweep the basic component objects of the lift system is
the buttons on the floors or inside the lifts. Buttons
have a common behaviour; they can be pushed On
by people and turned Off by the system. The projection symbol ns2 project in lakshadweep indicates visibility, i.e.
introduces the list of those features (local schema)
which are accessible via the dot notation. If the list is omitted, as in previous examples, all features are
visible. In the class Lift, the attribute fbuts (floor buttons)
models the panel of floor buttons where the ns2 project in lakshadweep index of
the sequence models the floor numbers. The attribute
md and ds models the move direction status and liftdoor
status. The attribute current models the floor
position where the lift is currently at. The attribute
extGoal represents an external request ns2 project in lakshadweep which is assigned
to the lift as a temporary destination. Inside a lift, a floor button can be selected by people.
This action is modelled by operation SelectFloor.
Note that the notation operation1 operation2 denotes ns2 project in lakshadweep
environment enrichment in that the schema
text of operation1 enriches the environment in which
operation2 is interpreted. This environment enrichment
frame also can used to model multiple concurrent
operation interactions. The lift door can ns2 project in lakshadweep be opened and closed.
There are two kinds of move operations: one
is driven by the external request (MoveToExtGoal),
the other is driven by the internal request . The lift move direction is dominated
by the external request (if it has been assigned
to the lift) rather than the internal request. This is ns2 project in lakshadweep
ensured by the precondition extGoal = @ of the operation
- The system safety property (S), “The lift door must
be closed before any movement (Up or Down),” is
ensured by the predicate ds Closed in the preconditions
of both the operation MoveToExtGoal and
MoveToIntGoal. Also, as preconditions of both the
operation MoveToExtGoal and MoveToIntGoal requires
that there is an external and/or internal ns2 project in lakshadweep request,
therefore the system property (Pl), “When a
lift has no request, it should remain at its final destination”,
is ensured. The system property (P2), “The
lift has to satisfy an external floor request only if it
goes in the same direction or if the request is the external
destination of the lift”, is also captured in the
definition of the operation MoveToExtGoal. As the definition of some operations ToOpenDoor,
MoveToExtGoal and MoveToIntGoal are relatively
complex, to improve the understandability of the
model, we present a finite state machine diagram Figure
2 to highlight the essential behaviour of the lift. Because the main characteristic states of the lift are
the move direction and the door status. A permutation of ns2 project in lakshadweep the cross state space of MoveDzrectzon and
DoorStatus forms the states of the finite state machine
for the lift. Transactions between states are labelled
with Object-Z operations with instantiated preconditions.
The instantiated preconditions for each ns2 project in lakshadweep operations
are also partitioned and labelled so that they
can be presented in a reusable fashion. We believe this
improves the readability of the finite state machine diagram
for a complex system.