Elastic CRFs for Open-ontology Slot Filling

Fuente: arXiv
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Main Authors: Dai, Yinpei, Zhang, Yichi, Liu, Hong, Ou, Zhijian, Huang, Yi, Feng, Junlan
Format: Preprint
Published: 2018
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author Dai, Yinpei
Zhang, Yichi
Liu, Hong
Ou, Zhijian
Huang, Yi
Feng, Junlan
author_facet Dai, Yinpei
Zhang, Yichi
Liu, Hong
Ou, Zhijian
Huang, Yi
Feng, Junlan
contents Slot filling is a crucial component in task-oriented dialog systems that is used to parse (user) utterances into semantic concepts called slots. An ontology is defined by the collection of slots and the values that each slot can take. The most widely used practice of treating slot filling as a sequence labeling task suffers from two main drawbacks. First, the ontology is usually pre-defined and fixed and therefore is not able to detect new labels for unseen slots. Second, the one-hot encoding of slot labels ignores the correlations between slots with similar semantics, which makes it difficult to share knowledge learned across different domains. To address these problems, we propose a new model called elastic conditional random field (eCRF), where each slot is represented by the embedding of its natural language description and modeled by a CRF layer. New slot values can be detected by eCRF whenever a language description is available for the slot. In our experiment, we show that eCRFs outperform existing models in both in-domain and cross-domain tasks, especially in predicting unseen slots and values.
format Preprint
id arxiv_https___arxiv_org_abs_1811_01331
institution arXiv
publishDate 2018
record_format arxiv
spellingShingle Elastic CRFs for Open-ontology Slot Filling
Dai, Yinpei
Zhang, Yichi
Liu, Hong
Ou, Zhijian
Huang, Yi
Feng, Junlan
Computation and Language
Slot filling is a crucial component in task-oriented dialog systems that is used to parse (user) utterances into semantic concepts called slots. An ontology is defined by the collection of slots and the values that each slot can take. The most widely used practice of treating slot filling as a sequence labeling task suffers from two main drawbacks. First, the ontology is usually pre-defined and fixed and therefore is not able to detect new labels for unseen slots. Second, the one-hot encoding of slot labels ignores the correlations between slots with similar semantics, which makes it difficult to share knowledge learned across different domains. To address these problems, we propose a new model called elastic conditional random field (eCRF), where each slot is represented by the embedding of its natural language description and modeled by a CRF layer. New slot values can be detected by eCRF whenever a language description is available for the slot. In our experiment, we show that eCRFs outperform existing models in both in-domain and cross-domain tasks, especially in predicting unseen slots and values.
title Elastic CRFs for Open-ontology Slot Filling
topic Computation and Language
url https://arxiv.org/abs/1811.01331