CS 570: Midterm test 

Submit by November 20, 2002

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Everybody must work on his/her own!
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Problem 1: Study the Tiny Rule Engine (TRE). Describe its structure and 
components. Compare the TRE inference procedure, which does not depend
on the order of the rules in the rule base, to the forward chaining
procedure (which is order-dependent) in terms of efficiency, and explain
how the efficiency problem is handled in TRE. What improvements are
introduced in TRE to make it able to handle assumptions? Run FTRE
and comment on ex7 and ex8 (these are p.97 & p.98 examples implemented
in FTRE). Run N-queens example and explain the idea of choice sets
and chronological backtracking.


Problem 2: Using KM*, prove that Bob is happy given the following:

     1.  If Bob passes the test and wins a lottery, then Bob is happy.
     2.  If Bob studies for the test or Bob is lucky, then Bob passes
         the test.
     3.  Bob did not study for the test, but Bob is lucky.
     4.  If Bob is lucky, then Bob wins a lottery.

Can this problem be solved within a forward chaining inference framework?
Explain.

     I suggest the following formalization of these statements
     (& for logical AND, V for logical OR, ~ for logical NOT):

     1.  Passes_Bob_exam & Wins_Bob_lottery --> Happy_Bob
     2.  Studies_Bob V Lucky_Bob --> Passes_Bob_exam
     3.  ~ Studies_Bob & Lucky_Bob
     4.  Lucky_Bob --> Wins_Bob_lottery

         Prove:  Happy_Bob