L-CATA: A logic-based expert travel system

L-CATA (Logic-based Computer Aided Travel Assistant) is a logic-based expert database system, which asks the user to input his query specification, such as starting place, destination, constraints, rules and goals, etc., and outputs a list of flights meeting the traveller's specification; together with an alternative list which may not quite meet the user's specification but optimizes his goals. L-CATA is written as a deductive database system, and uses heuristic rules to prune its search of the database. Unlike other air-travel related expert systems, L-CATA does not attempt to model the traveller. Instead, L-CATA complements existing Computer Reservation Systems by providing comprehensive individually tailored advice and information to the traveller. There are several approaches to implement such a system. The logic approach is a very promising one, and the aims of L-CATA can be more easily achieved by using it. In this paper, we present a logic approach to the L-CATA expert database system, and provide a theoretical foundation for such a database system.