Learning More Effective Dialogue Strategies Using Limited Dialogue Move Features
Learning More Effective Dialogue Strategies Using Limited Dialogue Move Features
复制标题
使用有限的对话移动功能学习更有效的对话策略
DOI:
10.3115/1220175.1220199
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发表时间:
2006
期刊:
影响因子:
--
通讯作者:
Oliver Lemon
中科院分区:
文献类型:
--
作者:
Matthew Frampton;Oliver Lemon
We explore the use of restricted dialogue contexts in reinforcement learning (RL) of effective dialogue strategies for information seeking spoken dialogue systems (e.g. COMMUNICATOR (Walker et al., 2001)). The contexts we use are richer than previous research in this area, e.g. (Levin and Pieraccini, 1997; Scheffler and Young, 2001; Singh et al., 2002; Pietquin, 2004), which use only slot-based information, but are much less complex than the full dialogue "Information States" explored in (Henderson et al., 2005), for which tractabe learning is an issue. We explore how incrementally adding richer features allows learning of more effective dialogue strategies. We use 2 user simulations learned from COMMUNICATOR data (Walker et al., 2001; Georgila et al., 2005b) to explore the effects of different features on learned dialogue strategies. Our results show that adding the dialogue moves of the last system and user turns increases the average reward of the automatically learned strategies by 65.9% over the original (hand-coded) COMMUNICATOR systems, and by 7.8% over a baseline RL policy that uses only slot-status features. We show that the learned strategies exhibit an emergent "focus switching" strategy and effective use of the 'give help' action.