16,002 research outputs found
Combination Strategies for Semantic Role Labeling
This paper introduces and analyzes a battery of inference models for the
problem of semantic role labeling: one based on constraint satisfaction, and
several strategies that model the inference as a meta-learning problem using
discriminative classifiers. These classifiers are developed with a rich set of
novel features that encode proposition and sentence-level information. To our
knowledge, this is the first work that: (a) performs a thorough analysis of
learning-based inference models for semantic role labeling, and (b) compares
several inference strategies in this context. We evaluate the proposed
inference strategies in the framework of the CoNLL-2005 shared task using only
automatically-generated syntactic information. The extensive experimental
evaluation and analysis indicates that all the proposed inference strategies
are successful -they all outperform the current best results reported in the
CoNLL-2005 evaluation exercise- but each of the proposed approaches has its
advantages and disadvantages. Several important traits of a state-of-the-art
SRL combination strategy emerge from this analysis: (i) individual models
should be combined at the granularity of candidate arguments rather than at the
granularity of complete solutions; (ii) the best combination strategy uses an
inference model based in learning; and (iii) the learning-based inference
benefits from max-margin classifiers and global feedback
Deep Cascade Multi-task Learning for Slot Filling in Online Shopping Assistant
Slot filling is a critical task in natural language understanding (NLU) for
dialog systems. State-of-the-art approaches treat it as a sequence labeling
problem and adopt such models as BiLSTM-CRF. While these models work relatively
well on standard benchmark datasets, they face challenges in the context of
E-commerce where the slot labels are more informative and carry richer
expressions. In this work, inspired by the unique structure of E-commerce
knowledge base, we propose a novel multi-task model with cascade and residual
connections, which jointly learns segment tagging, named entity tagging and
slot filling. Experiments show the effectiveness of the proposed cascade and
residual structures. Our model has a 14.6% advantage in F1 score over the
strong baseline methods on a new Chinese E-commerce shopping assistant dataset,
while achieving competitive accuracies on a standard dataset. Furthermore,
online test deployed on such dominant E-commerce platform shows 130%
improvement on accuracy of understanding user utterances. Our model has already
gone into production in the E-commerce platform.Comment: AAAI 201
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