The Course Timetabling Problem Presented by Ben Paechter Napier University.
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Transcript of The Course Timetabling Problem Presented by Ben Paechter Napier University.
The Course Timetabling Problem
Presented by Ben PaechterNapier University
Course Timetabling by Ben Paechter, Napier University, for the EvoNet Summer School 2001 2
Introduction
In order to produce the timetable for a University, we have to place the classes into:
Timeslots (e.g. Wednesday 3.00-4.00pm)Rooms (e.g. Room 115)
Let’s assume people (students , lecturers) are already assigned.
Course Timetabling by Ben Paechter, Napier University, for the EvoNet Summer School 2001 3
Goal
We want to produce:
Feasible Timetables Good Timetables
Course Timetabling by Ben Paechter, Napier University, for the EvoNet Summer School 2001 4
Feasible Timetables
Every person can attend every class. Not at two classes at once Travel time OK Time for lunch, etc
Each class is assigned a suitable room Big enough Right equipment Disabled access, etc
Course Timetabling by Ben Paechter, Napier University, for the EvoNet Summer School 2001 5
Good Timetables
People and the institution like the timetable. Efficient use of rooms Minimal movement Not too many classes in a row Lecturers have days with no teaching No large gaps in a day Unpopular times avoided
Course Timetabling by Ben Paechter, Napier University, for the EvoNet Summer School 2001 6
Size of the Problem
A typical institution (Napier University) has 2000 classes
200 rooms
45 timeslots
Number of different timetables is
(200*45)2000 – about 108000
The vast majority of these are infeasible.
Course Timetabling by Ben Paechter, Napier University, for the EvoNet Summer School 2001 7
Summer School Problem
Scaled down (but still big) You must find a good feasible timetable in a
short amount of time. Feasible means
Students don’t have any clashes Rooms are big enough and of the right type
Best means: Minimum occurrences of three classes in a row Minimum occurrences of a single class in a day
Course Timetabling by Ben Paechter, Napier University, for the EvoNet Summer School 2001 8
Ways you might solve it:Direct Representation
Each event has a timeslot and room encoded in the chromosome
Might have problems with the large number of infeasible timetables
Course Timetabling by Ben Paechter, Napier University, for the EvoNet Summer School 2001 9
Ways you might solve it:Indirect Representation
The chromosome tells us something about how to build the timetable.
There is a separate timetable builder parameterised by the chromosome.
Parameters might be:A suggested time (and room?) for each classThe heuristics to use at various stages of the
buildThe order of considering the classes
Course Timetabling by Ben Paechter, Napier University, for the EvoNet Summer School 2001 10
Other ways you might solve it:
Decreasing UniverseAssume an infinite number of rooms and
eventsMany more timetables are feasibleGradually reduce the size of the universe
Graph TheoryE.g. find sets of things that can happen at
the same time
Course Timetabling by Ben Paechter, Napier University, for the EvoNet Summer School 2001 11
Ways you might solve it:Something Else
It doesn’t matter so long as it works!
Course Timetabling by Ben Paechter, Napier University, for the EvoNet Summer School 2001 12
You will be given
A windows program to produce (text based) problem file instances of varying hardness. Each instance has at least one perfect solution.
A windows program to check each (text based) problem solution.
More detailed instructions about the problem.
Course Timetabling by Ben Paechter, Napier University, for the EvoNet Summer School 2001 13
You will produce
A program (Windows or Linux) that takes the text input file and produces the text output file
Comments on what your program seems to be good at, and what it seems not so good at
Ideas for further research