An expert system for mapping acoustic cues into phonetic features

Abstract

The paper describes the conception of the sublexical levels of a speech-understanding system as a society of experts. Experts cooperate in extracting and describing acoustic cues, generating and verifying phonetic hypotheses, and accessing a large lexicon. The knowledge of each expert is described by a frame language which allows integration between structural and procedural knowledge. Structural knowledge deals with relations between facts like acoustic-cue descriptions and phonetic-feature hypotheses. Procedural knowledge deals with rules for the use of relations, for the generation of contextual constraints for relation application, and for the extraction of new cues in specified contexts. The main purpose of the research proposed here is that of providing at the same time a model for computer perception and algorithms useful for designing complex systems operating in real time. Some experimental results on the performance of the proposed system are reported.