基于意图-槽关联建模的意图预测与槽填充联合方法
Intent-Slot Correlation Modeling for Joint Intent Prediction and Slot Filling
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摘要: 1、研究背景(context)
口语理解系统(Spoken language understanding)是用于解析人类语言语义框架的常用方法,其在对话系统中发挥着重要的作用。口语理解系统主要由意图识别和槽填充两个基本任务组成。意图识别用于判断语言所表达的意图。槽填充则从语言中提取出关键信息作为自然语言查询的约束条件。
2、目的(Objective)
在语义框架解析中,槽位词和意图表现出很强的相关性。这体现在,在每个句子中,槽位词中蕴含的指示信息对句子所表达的意图起到决定作用,同时意图类别决定了槽位词的标注。然而,已有研究工作鲜有显式建模意图和槽位词之间的关联,导致这种关联信息并没有得到充分利用。本文关注意图和槽位词之间关联的显式建模,并提出一种基于意图-槽关联建模的意图预测与槽填充联合方法。所提模型将对口语理解系统的发展起到促进作用。
3、方法(Method)
首先,本文通过区分槽位词与其他词研究槽位词对意图的影响,进而将槽位词的识别看做一个序列标注任务,并提出通过双向长短时记忆(BiLSTM)模型解决该任务。其次,将槽位词识别的结果引入到基于注意力的意图预测和槽填充中,以优化语义解析的结果。另外,本文在槽填充任务中集成了槽-门控机制,以建模槽位词对意图的依赖关系。最后,本文利用联合优化训练方法实现槽位词识别、意图识别和槽填充三个任务。
4、结果(Result)
本文分别在ATIS与Snips数据集上进行了试验。所提模型在语义框架解析准确度方面分别在两个数据集上达到了86.4和78.5的成绩。实验结果表明,所提模型通过更加轻量的模型达到了目前该任务的最佳结果。此外,消融试验的结果进一步表明槽位词识别可有效促进模型的全局优化。
5、结论(Conclusions)
本文所提基于意图-槽关联建模的意图预测与槽填充联合方法,有效提高了语义框架解析的性能,而模型中设计的槽位词识别部分有效促进了意图识别、槽填充和语义框架解析。本文相信该工作将促进口语理解系统的发展和应用,并启发更多的相关研究。Abstract: Slot filling and intent prediction are basic tasks in capturing semantic frame of human utterances. Slots and intent have strong correlation for semantic frame parsing. For each utterance, a specific intent type is generally determined with the indication information of words having slot tags (called as slot words), and in reverse the intent type decides that words of certain categories should be used to fill as slots. However, the Intent-Slot correlation is rarely modeled explicitly in existing studies, and hence may be not fully exploited. In this paper, we model Intent-Slot correlation explicitly and propose a new framework for joint intent prediction and slot filling. Firstly, we explore the effects of slot words on intent by differentiating them from the other words, and we recognize slot words by solving a sequence labeling task with the bi-directional long short-term memory (BiLSTM) model. Then, slot recognition information is introduced into attention-based intent prediction and slot filling to improve semantic results. In addition, we integrate the Slot-Gated mechanism into slot filling to model dependency of slots on intent. Finally, we obtain slot recognition, intent prediction and slot filling by training with joint optimization. Experimental results on the benchmark Air-line Travel Information System (ATIS) and Snips datasets show that our Intent-Slot correlation model achieves state-of-the-art semantic frame performance with a lightweight structure.