We describe SLING, a framework for parsing natural language into semantic
frames. SLING supports general transition-based, neural-network parsing with
bidirectional LSTM input encoding and a Transition Based Recurrent Unit (TBRU)
for output decoding. The parsing model is trained end-to-end using only the
text tokens as input. The transition system has been designed to output frame
graphs directly without any intervening symbolic representation. The SLING
framework includes an efficient and scalable frame store implementation as well
as a neural network JIT compiler for fast inference during parsing. SLING is
implemented in C++ and it is available for download on GitHub.

SLING 是一个用于将自然语言解析成语义框架的框架，使用双向 LSTM 输入编码和输出解码的转换式神经网络解析，可直接输出帧图而无需任何符号表示。

SLING：用于框架语义解析的框架

SLING: A framework for frame semantic parsing

This paper describes a parsing model that combines the exact dynamic
programming of CRF parsing with the rich nonlinear featurization of neural net
approaches. Our model is structurally a CRF that factors over anchored rule
productions, but instead of linear potential functions based on sparse
features, we use nonlinear potentials computed via a feedforward neural
network. Because potentials are still local to anchored rules, structured
inference (CKY) is unchanged from the sparse case. Computing gradients during
learning involves backpropagating an error signal formed from standard CRF
sufficient statistics (expected rule counts). Using only dense features, our
neural CRF already exceeds a strong baseline CRF model (Hall et al., 2014). In
combination with sparse features, our system achieves 91.1 F1 on section 23 of
the Penn Treebank, and more generally outperforms the best prior single parser
results on a range of languages.

本文利用神经网络方法，结合了准确的 CRF 解析动态规划和丰富的非线性特征，提出了一种解析模型。该模型结构上基于 CRF，以锚定规则制作因素，而不是使用基于稀疏特征的线性势函数，使用前馈神经网络计算非线性势函数。在 Penn Treebank 第 23 节上，我们的系统优于先前最佳单个解析器结果，F1 分数达到 91.1。

神经 CRF 解析

Neural CRF Parsing

We propose a technique for learning representations of parser states in
transition-based dependency parsers. Our primary innovation is a new control
structure for sequence-to-sequence neural networks---the stack LSTM. Like the
conventional stack data structures used in transition-based parsing, elements
can be pushed to or popped from the top of the stack in constant time, but, in
addition, an LSTM maintains a continuous space embedding of the stack contents.
This lets us formulate an efficient parsing model that captures three facets of
a parser's state: (i) unbounded look-ahead into the buffer of incoming words,
(ii) the complete history of actions taken by the parser, and (iii) the
complete contents of the stack of partially built tree fragments, including
their internal structures. Standard backpropagation techniques are used for
training and yield state-of-the-art parsing performance.

该文提出了一种新的序列到序列神经网络控制结构 —— 堆栈 LSTM，用于学习过渡式依赖解析器的解析状态，将其应用于解析模型中，实现了解析器状态的三个方面，提高了解析性能。