The cu communicator system 1

TLDR: The CU Communicator system is an initial testbed for research leading to advanced dialog systems enabling robust and graceful human computer interaction and the development of tools to facilitate rapid creation of spokendialog applications by non-expert developers is developed.

Abstract: The CU Communicator system is our initial testbed for researchleading to advanced dialog systems enabling robust and gracefulhuman computer interaction. It is a DARPA hub compliantsystem for the DARPA Communicator task, and wasdemonstrated at the DARPA workshop in June 1999.Robustness and portability of spoken dialog systems are two ofthe issues we attempt to address in the project. We use robustparsing and dialog control strategies to be as flexible as possibleto user variance. In order to make the systems easier to develop,we have adopted a largely declarative representation where thebulk of the domain specific information is provided in externalfiles. 1. INTRODUCTION In April 1999, the University of Colorado speech group begandevelopment of the CU Communicator system, a Hub-compliant implementation of the DARPA Communicatortask[1][2].The system combines continuous speech recognition,natural language understanding and flexible dialog control toenable natural conversational interaction by telephone callers toaccess information about airline flights, hotels and rental cars.In June 1999, the system was fully functional, and wasdemonstrated at the June 1999 DARPA Communicator meeting.This system connects live over the web to get real up-to-date airtravel, hotel and rental car information. Users call the system onthe telephone and make travel plans. We are using the system asa testbed for conversational system technology development. Forthis system, we developed a new Dialog Manager using an eventdriven strategy. Our natural language and dialog specificationfor the task is very much declarative.Our approach to robustness in natural language understanding isto use robust parsing strategies and event driven dialogstrategies. These strategies stress semantic content andcoherence over syntactic form. We have extended the Phoenixsystem as the basis for our robust parsing. This system uses ahierarchical frame parse representation. Our “event driven”dialog manager does not use an explicit script. The developercreates a set of hierarchical forms, representing the informationthat the system and user interact about. Prompts are associatedwith fields in the forms. The dialog manager decides what to donext from the current system context, not from a script.We also attempt to address issues of authoring and portability.Building a spoken dialog system is labor intensive and requiresa great deal of expertise. A major focus of our research is thedevelopment of tools to facilitate rapid creation of spokendialog applications by non-expert developers. Our initial stepshave been:• Declarative representation – To the extent possible, we arerepresenting information in external files rather thanhaving the developer write code.• Libraries – We are creating a library of common grammarsthat would be applicable to many tasks (times, dates, etc).