CS322 Fall 1999
Module 7 (Knowledge Representation Issues)
Due: 1:30pm, Friday 29 October 1999.
The aim of this assignment is to learn about some knowledge
representation issues that will be used later in the course.
Consider the relations:
Consider the knowledge base:
- course(Id,Year,Inst,Room,Limit) that is true if the course
with identifier Id, in year Year has instructor Inst, is held in
room Room and has a limit of Limit students.
- limit(Id,Year,Limit) that is true if the course
with identifier Id, in year Year has a limit of Limit students.
Check that your representation works with CIlog. Your new axiomatization should be able
to answer exactly the same limit queries as the original version.
Suppose a conditional expression is either:
- Give the knowledge base where we represent the course relation using
the object-attribute-value representation. (I.e., specify the above
three facts for course in terms of the prop relation.)
- Define limit
in terms of this new representation for the course
information. (The limit relation should have the same semantics as
- Explain why it may be advantageous to use the
object-attribute-value representation for course information.
You are to write a relation
- a value, where a value is either a number or is a Boolean value (true or
- is of the form if(Att,Then,Else) where Att is a Boolean
attribute, and Then and Else are conditional expressions.
To evaluate a conditional expression for an individual is simple: if
the conditional expression is a value, then that value is returned. If
the conditional expression is of the form if(Att,Then,Else), then if
the value of the attribute Att for the individual is true, you
evaluate the Then conditional expression, otherwise evaluate the
Else conditional expression.
- ceval(Obj,CE,Val) where Obj is an object, CE is a
conditional expression and Val is the resulting value of evaluating
the conditional expression for the individual Obj.
For example, given the knowledge base:
should return Val=80.
For each question in this assignment, say how long you spent on it.
reasonable? What did you learn?