tailieunhanh - Báo cáo khoa học: "Knowledge acquisition for a constrained speech system using WoZ"

In the last three iterations 23 subjects performed in all 107 dialogues with 28 different scenarios using a total of 4455 words. The constraints (1) and (2) above on vocabulary size and maximum and average user utterance length have been met. In the last iteration only 3 user utterances out. of 881 contained more than 10 tokens and the average number of tokens per user turn was . | Knowledge acquisition for a constrained speech system using WoZ Laila Dybkjaer Niels Ole Bernsen Hans Dybkjaer Centre for Cognitive Informatics CCI Roskilde University PO Box 260 DK-4000 Roskilde Denmark emails laila@ nob@ dybkjaer@ This paper describes the knowledge acquisition phase in a national project1 aimed at the design of realistic spoken language dialogue system prototypes in the domain of airline ticket reservation and flight information Dybkjaer and Dybkjaer 1993 . The goals of the knowledge acquisition phase were to define a dialogue structure and a sublanguage vocabulary and grammar for subsequent implementation of a first prototype. The development method was the Wizard of Oz simulation technique Fraser and Gilbert 1991 . The dialogue model had to satisfy a number of conflicting constraints most importantly 1 A maximum user vocabulary of 500 word forms. 2 A maximum user utterance length of 10 words and an average length of 3-4 words. 3 A usable dialogue including sufficient domain and task coverage robustness and real-time system performance. 4 A natural form of dialogue and language. A usable system is one which can do the tasks required of it. In principle it can replace a human operator on those tasks. A natural system on the other hand is one which allows users to use free and unconstrained spontaneous speech in efficiently achieving their goals. In the development of the first prototype to be described here the focus was on usability constraints l - 3 above and on laying the foundations for meeting the naturalness constraint 4 in a second prototype. The real-time requirement of 3 forces the recogniser to handle at most 100 active words at a time and together with 1 and 2 this obviously pushes the dialogue model towards a rigid system-directed dialogue structure. Seven iterations of Wizard of Oz experiments were performed involving taped and transcribed dialogues between the wizard and subjects. Voice distorting hardware .