Title
The Hidden Agenda User Simulation Model
Abstract
A key advantage of taking a statistical approach to spoken dialogue systems is the ability to formalise dialogue policy design as a stochastic optimization problem. However, since dialogue policies are learnt by interactively exploring alternative dialogue paths, conventional static dialogue corpora cannot be used directly for training and instead, a user simulator is commonly used. This paper describes a novel statistical user model based on a compact stack-like state representation called a user agenda which allows state transitions to be modeled as sequences of push- and pop-operations and elegantly encodes the dialogue history from a user's point of view. An expectation-maximisation based algorithm is presented which models the observable user output in terms of a sequence of hidden states and thereby allows the model to be trained on a corpus of minimally annotated data. Experimental results with a real-world dialogue system demonstrate that the trained user model can be successfully used to optimise a dialogue policy which outperforms a hand-crafted baseline in terms of task completion rates and user satisfaction scores.
Year
DOI
Venue
2009
10.1109/TASL.2008.2012071
IEEE Transactions on Audio, Speech & Language Processing
Keywords
Field
DocType
dialogue history,conventional static dialogue corpus,observable user output,dialogue policy design,alternative dialogue path,dialogue system,hidden agenda user simulation,trained user model,novel statistical user model,real-world dialogue system,dialogue policy,state transition,design optimization,simulation model,limiting,helium,markov decision process,stochastic optimization,parameter estimation,uncertainty,delta modulation,speech synthesis,stochastic processes,history,noise measurement,speech processing,speech recognition,user model,data models
Data modeling,Speech processing,Stochastic optimization,Markov process,Computer science,Expectation–maximization algorithm,Markov decision process,Speech recognition,User modeling,Artificial intelligence,Statistical model,Machine learning
Journal
Volume
Issue
ISSN
17
4
1558-7916
Citations 
PageRank 
References 
7
0.52
17
Authors
2
Name
Order
Citations
PageRank
Jost Schatzmann168837.81
S. Young21347.84