An Island Parsing Interpreter For The Full Augmented Transition Network Formalism

Island parsing is a powerful technique for parsing with Augmented ~ansition Networks (ATNs) which was developed and successfully applied in the HWIM speech understanding project. The HWIM application grammar did not, however, exploit Woods' original full ATN specification. This paper describes an island parsing interpreter based on HWIM, but containing substantial and important extensions to enable it to interpret any grammar which conforms to that full specification of 1970. The most important contributions have been to eliminate the need for prior specification of scope clauses, to provide more power by implementing LIFTR and SENDR actions within the island parsing framework, and to improve the efficiency of the techniques used to merge together partially-built islands within the utterance. This paper also presents some observations about island parsing, based on the use of the parser described, and some suggestions for future directions for island parsing research.