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NLP-progress

Repository to track the progress in Natural Language Processing (NLP), including the datasets and the current state-of-the-art for the most common NLP tasks.

Dependency parsing

Dependency parsing is the task of extracting a dependency parse of a sentence that represents its grammatical structure and defines the relationships between “head” words and words, which modify those heads.

Example:

     root
      |
      | +-------dobj---------+
      | |                    |
nsubj | |   +------det-----+ | +-----nmod------+
+--+  | |   |              | | |               |
|  |  | |   |      +-nmod-+| | |      +-case-+ |
+  |  + |   +      +      || + |      +      | |
I  prefer  the  morning   flight  through  Denver

Relations among the words are illustrated above the sentence with directed, labeled arcs from heads to dependents (+ indicates the dependent).

Penn Treebank

Models are evaluated on the Stanford Dependency conversion of the Penn Treebank with predicted POS-tags. Punctuation symbols are excluded from the evaluation. Evaluation metrics are unlabeled attachment score (UAS) and labeled attachment score (LAS).

Model UAS LAS Paper / Source
Stack-only RNNG (Kuncoro et al., 2017) 95.8 94.6 What Do Recurrent Neural Network Grammars Learn About Syntax?
Semi-supervised LSTM-LM (Choe and Charniak, 2016) 95.9 94.1 Parsing as Language Modeling
Deep Biaffine (Dozat and Manning, 2017) 95.66 94.03 Deep Biaffine Attention for Neural Dependency Parsing
Andor et al. (2016) 94.61 92.79 Globally Normalized Transition-Based Neural Networks
Distilled neural FOG (Kuncoro et al., 2016) 94.26 92.06 Distilling an Ensemble of Greedy Dependency Parsers into One MST Parser
Weiss et al. (2015) 94.0 92.0 Structured Training for Neural Network Transition-Based Parsing
Arc-hybrid (Ballesteros et al., 2016) 93.56 91.42 Training with Exploration Improves a Greedy Stack-LSTM Parser
BIST parser (Kiperwasser and Goldberg, 2016) 93.2 91.2 Simple and Accurate Dependency Parsing Using Bidirectional LSTM Feature Representations

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