A Malay proverb "jika sesat di hujung jalan, baleklah kepangkal jalan" roughly means "if you get lost at the end of the road, go back to the beginning". In going back to the beginning of the road, we learn our mistakes and hopefully will not repeat the same mistake again. Thus, this work investigates the use of formal logic as a practical tool for reasoning why we could not infer or deduce a correct answer from a question posed to a database.
An extension of the Prolog interpreter is written to mechanise
a theorem-proving system based on Horn clauses. This extension
procedure will form the basis of the question-answering
system. Both input into and output from this system is in the
form of predicate calculus. This system can answer all four
classes of questions as classified by Chang and Lee (1973). [Continues.]
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy at Loughborough University.
Universiti Kebangsaan Malaysia (Bangi, Malaysia). Malaysia, Public Service Department (JPA).