Drew McDermott, Ruven Brooks
Arby is a software system or higher order language for writing expert systems to do diagnosis in electronic systems. As such, it is similar to EMYCIN (Van Melle 1982) in application, but quite different in design. It is rule-based to an extent, but the rules are written in predicate calculus. It resembles Caduceus (Pople 1977) in its mechanisms for refining and combining hypotheses.