Spoken Dialogue in Information Retrieval

1. Spoken Dialogue in Information Retrieval Jia-lin Shen Oct. 22, 1998

2. Outline • Introduction • Spoken Dialogue Technologies • Spoken Dialogue in Information Retrieval • Information Retrieval in Spoken Dialogue • Some Speech Information Retrieval Examples • Conclusion

3. Introduction Speech Processing Applications Command control Data entry Consumer electronics Telephony Synthesis Verification/ Identification

4. Introduction • Using speech in information retrieval system Text database / Speech database • Platform : • Computer • Consumer electronic products • Telephone Database Input queries Retrieved documents Information Retrieval System Text output / Speech output Text input / Speech input

5. Introduction • The impact of speech in information retrieval system • Speech input : data entry • Speech output :synthesis • Multimedia database : including speech, text, image • Platform : • Consumer electronic products : PDA, remote controller, GPS... • Telephone • Personalization : speaker identification/verification

6. Introduction • Advantages using speech • Naturalness • Penetrability • Convenience • Platform flexibility • Drawbacks using speech • Probability • Variability • Security

7. Spoken Dialogue • Spoken Dialogue system • Telephony-based speech interactive system Acoustic models Lexicon Language models Syntactic models Semantic models Concept grammar Telephony-based Speech Recognition Language Understanding Speech Synthesis Language Generation Dialogue Control Database Discourse context

8. Spoken Dialogue • Related Research Topics in spoken dialogue • Telephony based speech recognition • Robustness in dealing with both speaker variability and environment variability • Language understanding • Corpus-based statistical approach • Rule based syntactic/semantic driven approach • Dialogue control • Language generation / speech synthesis • Spoken dialogue system evaluation • Architecture development in spoken dialogue system • Client-server platform

9. Spoken Dialogue in Information Retrieval • Data entry platform • Wired/wireless telephone • Output retrieved documents using speech • Precision rates are much more important than recall rates • Dialogue control technology helps Interactive communication between human and machine • Language understanding technology improves query input from text to concept • Speaker verification/identification using speech can help security for personalization

10. Information Retrieval in Spoken Dialogue • Input queries are usually proper nouns, which are out-of-vocabulary terms in the lexicon for speech recognition • Non-grammatical and very short input queries leads to the degradation in language modeling • Speaker independence over the telephone is highly desired • Confidence measure (probabilistic / deterministic) due to speech recognition errors • Speech coding/transmission in internet

11. Some Examples • Air travel information service (ATIS) in USA • Best performance - at the end of 1995 • Understanding error rate of 5.9% and 8.9% for text and speech input, respectively • Flight and train schedule inquiry system in Europe • Multilingual : English, French, German, Italian • MIT Galaxy weather inquiry system • Telephone Directory Services for Financing /Banking Organizations in Taipei Area

12. Conclusion • What role can SPEECH play in information retrieval ? • What impact can spoken dialogue make in information retrieval ?