1. For the following scenaro do the appropriate Analysis and
Design. Use either ProxyDesigner, Objecteering,
Rational Rose or other suitable UML Design tool to complete this question.
A Traffic Light System
You've are to construct a traffic light system for a city. Assume the
system is self contained ( isolated); that is, it does
not have to interface to any existing systems. The system must support
between 10 and 100 intersections.
The lights at each intersection are to have the following features:
each light has the usual red, green, and yellow
lamps; these work in the usual way (but see below for more details),
with yellow lamps being on for 30 seconds
when activated if an intersection has any lights, there is a set
of lights
for each direction traffic travels some
intersections have left turn lanes and/or right turn lanes some intersections
have walk/don't walk lights; the walk light
turns on at the same time as the green going in the same direction,
the don't-walk light starts flashing once
per second when the yellow is on, and the don't-walk light is on (steady)
when the red is on
each intersection with lights contains a sensor which detects the emergency
lights on police
cars, firetrucks, and ambulances; when the
sensor detects an emergency light with the proper characteristics
(which differs by vehicle), the traffic
light automatically cycles so that the light is green in the direction
the
emergency vehicle is travelling; if the vehicle
is too close to an intersection to allow a full 30-second yellow
cycle, the cycle is cut short lights
on one-way streets are timed so vehicles driving at a constant 25 mph need
not stop lights on two-way streets are tied
to sensors burried in the road which detect when a car is present;
these lights have minimum and a maximum times
for each green, and the presence of a car in the other direction
between these times will cause the light
to cycle from green to red each intersection contains counters showing
the number of cars travelling through it in
each direction; the system records the total number of cars travelling
through each intersection for each hour, and
this data is passed to a proprietary (purchased) system which
computes optimal times for the traffic lights
in the system
For the above scenaro do the following:
1.Draw a use case diagram. Treat the computer which computes
times for the traffic lights as an external actor.
Other actors include general vehicles,
emergency vehicles, and pedestrians. Using a word processor, write
at least one scenario for each use case,
and possibly more for interesting cases. In particular, your list of
scenarios must include the following:
a car stopping
at a light and triggering the sensor at that light
an ambulance
triggering the sensor that causes the light to change
sending data
to the computer which computes times for the traffic lights; note this
scenario must describe
how the lights become resynchronized with
the new plan
2.Draw at least 4 sequence diagrams for 4 of the more
interesting scenarios. (That is, 4 total; not 4 for each scenario!)
Three of the scenarios must be the ones listed
above, but you are free to pick the others. "More interesting"
means the diagrams should include a number
of classes and messages.
3.Create a design-level class diagram. Be sure to include
appropriate attributes and operations, and be sure to mark
composition, navigability, derived associations,
interface classes, and abstract classes where appropriate.
4.Draw a collaboration Diagram .
5.Draw state diagrams for the SensorLight and PedestrianLight
classes. The SensorLight diagram should take into
account handling emergency vehicles
as well as the other features mentioned above; this will be a
large diagram.
Use one of the aforementioned tools to create your answer.
This is individual work .Do not copy from any source.
2 Give a complete detailed outline of the Object
Analysis and Design Process . This is to be an outline not an essay.
Submit all answers to me in electronic form via email by 8:00AM Tuesday Morning, December 11, 2001