Frame heuristics examples
These examples have been taken directly from Jackson's Problem Frames
book. This handout is used in conjunction with Week 10.
Tennis Court Lights
A tennis club has a new and very expensive indoor
court. 'Indoors' members pay a special extra subscription, and pay for
lighting. An indoor game must include at least one 'indoors' member. The
lighting cost is billed to and 'indoors' member included in the game.
'Indoors' members are issued with magnetic cards. The court entrance lock
and the lighting control box can read these cards. To use the indoor court
a member inserts the card into the lock and gains entry. Inside the court,
the card is inserted into the lighting control box and the desired playing
time is entered. The lights then come on and remain on for that length of
time. A computer system is needed: to manage general and 'indoors'
subscriptions; to operate the lights by managing the lighting control box
and the court entrance lock; and to manage the billing and receipts for
Home Heating Control
A home heating system uses hot water radiators. …
The computer must regulate the behaviour of the system to maintain room
temperatures as set on the control knobs. For economy, the temperature of
an unoccupied room should be 5 degrees below the knob setting. The system
should use information from the occupancy sensors to anticipate room use,
starting to raise the temperature 30 minutes before occupancy is expected.
In a system to manage undergraduate degree courses,
students enrol for course modules by online interaction with the computer
system. The result of these interactions is, of course, to change the
states of model domains in the system that model the states of the course
modules and of the enrolled students. Other people - administrative staff
and faculty members - also use the system. They enter various information
about the students and the courses: for example, that an undersubscribed
module has been cancelled, or that a student has been awarded a particular
Air Traffic Control
There are two runways. Runway A is… Runway B is…
Here's how planes behave in the air and when landing and taking off…
The system must ensure a horizontal separation of
at least 10,000 feet and a vertical separation of at least 2000 feet
between planes at all times.
If at any time the separation between two planes
in the air is less than the required minimum, the system should…