Strongly Incremental Constituency Parsing with Graph Neural Networks-猫眼课题宝

DOI：

发表时间：

2020-10

期刊：

ArXiv

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其他

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作者：

Kaiyu Yang;Jia Deng

将句子解析成语法树可以使NLP中的下游应用受益。基于转换的解析器通过在状态转换系统中执行动作来构建树。它们在计算上是高效的，并且可以利用机器学习来预测基于部分树的动作。然而，现有的基于转换的解析器主要基于移位-归约转换系统，这与人类已知的解析句子的方式不一致。心理语言学研究表明，人类的解析是强烈的增量：人类通过在每一步添加一个标记来生长一个解析树。在本文中，我们提出了一种新的过渡系统称为附加并置。它是强增量的;它使用一棵树表示一个部分句子;每个动作只向部分树中添加一个标记。基于我们的转换系统，我们开发了一个强增量解析器。在每一步中，它使用图神经网络对部分树进行编码，并预测动作。我们在Penn树库（PTB）和中文树库（CTB）上对我们的解析器进行了评估。在PTB上，它的性能优于仅使用选区树训练的现有解析器;并且它的性能与使用依赖树作为额外训练数据的最先进解析器相当。在CTB上，我们的解析器建立了一个新的技术状态。代码可以在这个https URL上找到。

Parsing sentences into syntax trees can benefit downstream applications in NLP. Transition-based parsers build trees by executing actions in a state transition system. They are computationally efficient, and can leverage machine learning to predict actions based on partial trees. However, existing transition-based parsers are predominantly based on the shift-reduce transition system, which does not align with how humans are known to parse sentences. Psycholinguistic research suggests that human parsing is strongly incremental: humans grow a single parse tree by adding exactly one token at each step. In this paper, we propose a novel transition system called attach-juxtapose. It is strongly incremental; it represents a partial sentence using a single tree; each action adds exactly one token into the partial tree. Based on our transition system, we develop a strongly incremental parser. At each step, it encodes the partial tree using a graph neural network and predicts an action. We evaluate our parser on Penn Treebank (PTB) and Chinese Treebank (CTB). On PTB, it outperforms existing parsers trained with only constituency trees; and it performs on par with state-of-the-art parsers that use dependency trees as additional training data. On CTB, our parser establishes a new state of the art. Code is available at this https URL.

Strongly Incremental Constituency Parsing with Graph Neural Networks

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