Selecting Help Messages by Using Robust Grammar Verification for Handling Out-of-Grammar Utterances in Spoken Dialogue Systems

Kazunori KOMATANI  Yuichiro FUKUBAYASHI  Satoshi IKEDA  Tetsuya OGATA  Hiroshi G. OKUNO  

IEICE TRANSACTIONS on Information and Systems   Vol.E93-D   No.12   pp.3359-3367
Publication Date: 2010/12/01
Online ISSN: 1745-1361
DOI: 10.1587/transinf.E93.D.3359
Print ISSN: 0916-8532
Type of Manuscript: PAPER
Category: Speech and Hearing
spoken dialogue system,  help generation,  out-of-grammar utterances,  novice user,  utterance history,  

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We address the issue of out-of-grammar (OOG) utterances in spoken dialogue systems by generating help messages. Help message generation for OOG utterances is a challenge because language understanding based on automatic speech recognition (ASR) of OOG utterances is usually erroneous; important words are often misrecognized or missing from such utterances. Our grammar verification method uses a weighted finite-state transducer, to accurately identify the grammar rule that the user intended to use for the utterance, even if important words are missing from the ASR results. We then use a ranking algorithm, RankBoost, to rank help message candidates in order of likely usefulness. Its features include the grammar verification results and the utterance history representing the user's experience.