An Eclectic Approach to Building Natural Language Interfaces

AN ECLECTIC APPROACH TO BUILDING NATURAL LANGUAGE INTERFACES Brian Phillips. Michael J. Freiling, James H. Alexander, Steven L. M essick, Steve Rehfu~, Sheldon N ichollt Tektronix, Inc. P.O. Box 500, M/S 50-662 Beavertoa, OR 97077 ABSTRACT INKA is a natural language interface to facilitate knowledge acquisition during expert system development for electronic instrument trouble-thooting. The expert system design methodology develops a domain definition, called GLIB, in the form of a semantic grammar. This grammar for- mat enables GLIB to be used with the INGLISH interface, which constrains users to create statements within a subset of English. Incremental patting in INGLISH allows immediate remedial information to be generated if a user deviates from the sublanguage. Sentences are translated into production rules using the methodology of lexical-functional grammar. The sys- tem is written in Sms/ltalk and, in INK,A, produces rides for a Prolog inference engine. INTRODUCTION The ides/ natural language interface would let any user, without any prior training, interact with a computer. Such an interface would be useful in the knowledge acquisition phase of expert system development where the diagnostic knowledge of a Hilled practitioner has to be elicited. As technicians are not farnifiar with formal knowledge representation schemes, a trained intermediary, a knowledge engineer, is generally employed to handcraft the interns/ format. This process is time-consuming and expensive. INKA (INglish Knowledge Acquisition) permits task experts to express their knowledge in a subset of English, and have it automatically translated into the appropriate represen- tational formalism. In particular, the version of INKA to be discussed here accepts input in a sublanguage called GLIB which permits the statement of facts and rules relevant to the troubleshooting of electronic systems (Freiling et al., 1984), and translates these statements into Prolog unit clauses for later proce~ng by a specialized inference mechanism. Experiments with INKA to date have enabled us to construct mfflcient troubleshooting rules to build a localizing troubleshooter for a simple circuit. INKA is designed as one of the tools of DETEKTR, an environment for building knowledge based electronic instru. ment troubleshooters (Freiling & Alexander, 1984). DETEKTR supports an expert system development methodol- ogy which is outlined below. The design goal of INKA is that it serve as a natural language input system to facilitate transfer of knowledge during the knowledge acquisition phase of expert system development. IIqKA is not intended to stand alone as the sole mechanism for knowledge transfer, but to be sup- t A summer intern at Tektronix, currently at the Univer- sity of llfinois, Champs/gn-Urbana. ported by components capable of managing a coherent dis/o- gue with the task expert. McKeown (1984) has po/nted out a number of important aspec~ of the pragmatics that relate to the usage phase of an expert system. Similar pragmatics are required to insure adequate construction of the system's knowledge base during the knowledge ac~n phase of an expert system's development. The most important pragmatic facility is one to estimate the degree of epistemi¢ coverage of the knowledge acquired so far, and to prompt the …

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