ns2 project in kerala
ns2 project in kerala the remaining two schemas are operation schemas.
Operation schemas have a A-list of those attributes
whose values may change. By convention, no Alist
means no attribute changes value. Every operation ns2 project in kerala
schema implicitly includes the state schema in
un-primed form ,Operation ns2 project in kerala Leaveoutputs a value item! defined as the head of sequence
items and reduces items to the tail of its original value A history invariant is an optional predicate over histories
of objects of the class expressed in temporal logic.
Such predicates further constrain possible behaviour.
For example, suppose we wish to specify in the generic
queue that whenever Leave or Delete is continuously
enabled it must eventually occur. Objects ns2 project in kerala may have object references as attributes] i . 9
conceptually, an object may have constituent objects.
Such references may either be individually named or
occur in aggregates. For example, the declaration, C declares c to be a reference to an object of the class
described by C. A declaration c, d : C need not mean
that c and d reference distinct objects. If the ns2 project in kerala intention
is that they do so at all times, then the predicate c d
would be included in the class invariant.
The term c.att denotes the value of attribute att
of the object referenced by c, and c.Op denotes the
evolution of the object according to the ns2 project in kerala definition of
Op in the class C, A lift system for an multi-floor building consist of
multiple elevators. Inside the elevator there is a ns2 project in kerala panel
of floor buttons each of which indicates a destination
floor. Outside the elevator there are two direction ns2 project in kerala buttons
on each floor which call for service, one for up and
the other for down (except the first floor and ns2 project in kerala the top
floor on which only one button is needed). Any button
can be pushed at any time. Any external floor
button will be on from the time it is pushed until the
elevator with the same travel direction stops at the
floor and opens the door. Any internal ‘on’ button of
a lift will be turned off when the lift visits the corresponding
floor. safety property (S): The lift door must be closed
before any movement (Up or Down).
system property (Pl): When a lift has no ns2 project in kerala request,
it should remain at its final destination.
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. system property (P3): When a request arrives
from a floor the system will put the request at
the end of the external request queue.
system property (P4): If an external request in
the queue is serviced by some lift on the way Up
or Down, then this request should be removed
from the request queue. temporal property (Tl): whenever there are some
idle lifts and the external service queue is not empty, ns2 project in kerala the longest waiting request is
removed from the queue and assigned to one idle lift as the temporal final destination. temporal property (T2): All request for lifts from floors must be serviced eventually. temporal property (T3): All internal requests for
lifts must be serviced eventually. temporal property (T4): If a lift’s door is open,
eventually it will be closed.