CPSC 433: Artifical Intelligence Winter 2009 |
The assignment is based on the Sisyphus I problem-solving process modeling problem as used in the knowledge accusation community in the KAW series of workshops and other workshops and conferences. The problem has been reformulated (specialized, actually) to be a search problem for the purposes of this course.
The task is to assign office workers to offices, maximizing the happiness of the workers and convenience of the work environment (both of which are, of course, important for worker productivity). There are a large number of factors which our model uses to measure the "goodness" of a solution. These are modeled as constraints.
There are a few mandatory constraints that may not be violated. Any room assignment that violates these is not considered a solution. These are:
//everyone
is assigned a room
FORALL p:person . EXISTS r:room . assigned-to(p,r)
//
no person is assigned more than one room
FORALL p:person . ~ EXISTS r,s:room
| r /= s . assigned-to(p,r) /\ assigned-to(p,s)
// not more than 2 people
to a room
FORALL r:room . ~ EXISTS x,y,z:person | x /= y /\ x /= z /\ y /=
z . assigned-to(x,r) /\ assigned-to(y,r) /\ assigned-to(z,r)
//project
heads, group heads, and managers can't share a room with anyone else
FORALL
h:person, g:name | heads-project(h,g) \/ heads-group(h,g) \/ manager(h) . ~ EXISTS
p:person, r:room | p /= h . assigned-to(p,r) /\ assigned-to(h,r)
There are also a large number of "soft" constraints that may be violated (and since some of these constraints actually conflict with each other, must be violated). These all have a penalty associated with them (reflecting their importance). Your job is to come up with a solution that maximizes the utility function that naturally arises from these soft constraints and their penalty weightings. I have, of course, written my own version of this utility function that (I believe) precisely conforms to the these constraints, and I will test your program's solutions against my utility function. You will have to write your own utility function to test your program.
The soft constraints are available in PDF, Microsoft Word .doc format, and RTF. You will note that some of the formal semantics in the soft constraints table are omitted. These should be filled in on the table and the complete table should be submitted as an appendix to your group paper (which is due just before reading week).
The input and output file formats are the same, namely, a set of ASCII-format predicates, one per line. The BNF for this format is:
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There are also a few inference rules that you must observe when reading input files. These may be hard-coded if you wish.
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You will be pleased to learn that I have saved you the effort of writing a parser for the file format. See the JavaDoc documentation. You can download the following JAVA classes: :
(or download them all in a jar file which includes the .class files and manifest as well).
It is highly recommended that you use this parser
for your assignment, as it will save you a lot of trouble, it works, and might
avoid some possible problems with your assessment and demos. These classes make
use of the JAVA reflect package, so that you need only define methods a_predicateName()
(to assert a predicate as true) and/or e_predicateName()
(to
evaluate the truth value of a predicate). Your methods must also, of course, support
the appropriate parameter list. You may define additional predicates if you wish,
but the assessment will only require you to interpret the predicates listed here.
Be warned that the only predicate type expected in your output file is
the assigned-to(name,room-name)
predicate (and perhaps comments).
You can use the following sample text as a test suite for your program. It is the problem described in the Sisyphus I problem description. You will be tested on other scenarios.
// the YQT group staff descriptions researcher(Werner) group(Werner, YQT) project(Werner, RESPECT) hacker(Werner) works-with(Werner, {Angi, Marc}) researcher(Jurgen) researcher(Marc) researcher(Angi) researcher(Andy) researcher(Michael) researcher(Harry) researcher(Uwe) researcher(Thomas) secretary(Monika) secretary(Ulrike) researcher(Hans) manager(Eva) researcher(Joachim) researcher(Katharina) // project descriptions //
room sizes // room proximity |
The following is the solution suggested to the above problem in the Sisyphus I problem description. My utility function rates its utility at -163.
assign-to(Thomas,C5117) assign-to(Monika,C5119) assign-to(Ulrike,C5119) assign-to(Eva,C5116) assign-to(Joachim,C5115) assign-to(Hans,C5114) assign-to(Katharina,C5113) assign-to(Andy,C5120) assign-to(Uwe,C5120) assign-to(Werner,C5123) assign-to(Jurgen,C5123) assign-to(Marc,C5122) assign-to(Angi,C5122) assign-to(Harry,C5121) assign-to(Michael,C5121) |
Last updated 2009-04-07 22:08 |