1. © 2002 – 2007 Versay Solutions, LLC. All rights reserved. Building Fault Tolerant Voice User Interfaces SpeechTEK 2007 Tuesday, August 21 Track B “Getting the VUI Right when Recognition Goes Wrong”

2. © 2002 – 2007 Versay Solutions, LLC. All rights reserved. Versay Solutions, LLC Daniel Padgett Senior Speech Technology Consultant Jessica Peterson Hicks, Ph.D. Speech Technology Consultant

3. © 2002 – 2007 Versay Solutions, LLC. All rights reserved. Fault Tolerant Voice User Interfaces Error Prevention Error Resolution

4. © 2002 – 2007 Versay Solutions, LLC. All rights reserved. Directed Dialog Prompt Design Grammar Coverage

5. © 2002 – 2007 Versay Solutions, LLC. All rights reserved. Proof of Concept NL Routing Application Natural Language (NL) Main Menu –“How can I help you?” Main Menu Confirmation “Back Off” Menu to support Main Menu failures Disambiguation dialog states Form-filling dialog states

6. © 2002 – 2007 Versay Solutions, LLC. All rights reserved. Case Study – Back Off Main Menu Initial Prompt –Designed to handle exception cases from Main Menu –Options mapped to core business practices Grammar –Optimally constrained static grammar –5 slots / semantic interpretations

7. © 2002 – 2007 Versay Solutions, LLC. All rights reserved. Case Study – Back Off Main Menu

8. © 2002 – 2007 Versay Solutions, LLC. All rights reserved. Case Study – Main Menu Confirmation Initial Prompt –Dynamically constructed –Covered ~100 categories “Okay. [You need to change your address.] Is that right?” Grammar –Optimally constrained static grammar –2 slots / semantic interpretations

9. © 2002 – 2007 Versay Solutions, LLC. All rights reserved. Case Study – Main Menu Confirmation

10. © 2002 – 2007 Versay Solutions, LLC. All rights reserved. Robust Interpretation (RI) Statistical Language Models Interpretation Grammars

11. © 2002 – 2007 Versay Solutions, LLC. All rights reserved. RI – Back Off Main Menu Statistical Language Model –Training set of ~2500 utterances –Test set of ~1000 utterances Interpretation Grammar –8 slots / semantic interpretations

12. © 2002 – 2007 Versay Solutions, LLC. All rights reserved. RI – Back Off Main Menu

13. © 2002 – 2007 Versay Solutions, LLC. All rights reserved. RI – Main Menu Confirmation Statistical Language Model –Training set of ~3000 utterances –Test set of ~1000 utterances Interpretation Grammar –20 slots / semantic interpretations –Y, N, N+RoutingCategory, RoutingCategory

14. © 2002 – 2007 Versay Solutions, LLC. All rights reserved. RI – Main Menu Confirmation

15. © 2002 – 2007 Versay Solutions, LLC. All rights reserved. Error Prevention - Summary Robust Interpretation for two key states Considerable increases in coverage Significant decreases in no-match rates Minimal False-Accepts

16. © 2002 – 2007 Versay Solutions, LLC. All rights reserved. Fault Tolerant Voice User Interfaces Error Prevention Error Resolution

17. © 2002 – 2007 Versay Solutions, LLC. All rights reserved. Error Resolution Dialog State Error Strategy Universal Error Strategy Task-related Error Strategy

18. © 2002 – 2007 Versay Solutions, LLC. All rights reserved. Established Methods Dialog State Error Handling –Escalating error strategy –No-input and no-match handlers –Implicit DTMF Universal Error Handling –Increment for each no-match, no-input –Transfer when maximum exceeded

19. © 2002 – 2007 Versay Solutions, LLC. All rights reserved. Dialog State Error Strategy Escalating error handling –Rapid reprompt –Explicit DTMF on penultimate error prompt –Transfer on final error Combination of no-match and no-input handlers

20. © 2002 – 2007 Versay Solutions, LLC. All rights reserved. Universal Error Strategy Increment / decrement counter Score errors on distinct dimensions –Number –Consecutivity

21. © 2002 – 2007 Versay Solutions, LLC. All rights reserved. Task-related Error Strategy Determine “sensitivity” level for each call path Allow fewer errors on sensitive paths, more errors on less sensitive paths –Report a Problem = highly sensitive –Monthly Payment = moderately sensitive –Hours of Operation / Location = less sensitive

22. © 2002 – 2007 Versay Solutions, LLC. All rights reserved. Customer Service Universals Acknowledge Explain Re-prompt

23. © 2002 – 2007 Versay Solutions, LLC. All rights reserved. Customer Service Universals – Case Study

24. © 2002 – 2007 Versay Solutions, LLC. All rights reserved. Summary Fault Tolerance means striking the right balance between: Error Prevention Error Resolution

25. © 2002 – 2007 Versay Solutions, LLC. All rights reserved. Contact Us www.versay.com dpadgett@versay.com jhicks@versay.com (888) 869-0121