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 Grammars & Parsing


Measuring Compositionality in Representation Learning

arXiv.org Machine Learning

Many machine learning algorithms represent input data with vector embeddings or discrete codes. When inputs exhibit compositional structure (e.g. objects built from parts or procedures from subroutines), it is natural to ask whether this compositional structure is reflected in the the inputs' learned representations. While the assessment of compositionality in languages has received significant attention in linguistics and adjacent fields, the machine learning literature lacks general-purpose tools for producing graded measurements of compositional structure in more general (e.g. vector-valued) representation spaces. We describe a procedure for evaluating compositionality by measuring how well the true representation-producing model can be approximated by a model that explicitly composes a collection of inferred representational primitives. We use the procedure to provide formal and empirical characterizations of compositional structure in a variety of settings, exploring the relationship between compositionality and learning dynamics, human judgments, representational similarity, and generalization.


Learning to Generalize from Sparse and Underspecified Rewards

arXiv.org Machine Learning

We consider the problem of learning from sparse and underspecified rewards, where an agent receives a complex input, such as a natural language instruction, and needs to generate a complex response, such as an action sequence, while only receiving binary success-failure feedback. Such success-failure rewards are often underspecified: they do not distinguish between purposeful and accidental success. Generalization from underspecified rewards hinges on discounting spurious trajectories that attain accidental success, while learning from sparse feedback requires effective exploration. We address exploration by using a mode covering direction of KL divergence to collect a diverse set of successful trajectories, followed by a mode seeking KL divergence to train a robust policy. We propose Meta Reward Learning (MeRL) to construct an auxiliary reward function that provides more refined feedback for learning. The parameters of the auxiliary reward function are optimized with respect to the validation performance of a trained policy. The MeRL approach outperforms our alternative reward learning technique based on Bayesian Optimization, and achieves the state-of-the-art on weakly-supervised semantic parsing. It improves previous work by 1.2% and 2.4% on WikiTableQuestions and WikiSQL datasets respectively.


Parsing the Shadow Docket

Slate

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Improving Semantic Parsing for Task Oriented Dialog

arXiv.org Artificial Intelligence

Semantic parsing using hierarchical representations has recently been proposed for task oriented dialog with promising results [Gupta et al 2018]. In this paper, we present three different improvements to the model: contextualized embeddings, ensembling, and pairwise re-ranking based on a language model. We taxonomize the errors possible for the hierarchical representation, such as wrong top intent, missing spans or split spans, and show that the three approaches correct different kinds of errors. The best model combines the three techniques and gives 6.4% better exact match accuracy than the state-of-the-art, with an error reduction of 33%, resulting in a new state-of-the-art result on the Task Oriented Parsing (TOP) dataset.


Parsing of Audit Work Creates Opening for Technology Firms

WSJ.com: WSJD - Technology

Dividing the work could pave the way for companies to automate elements of the audit process, allowing them to free up human resources to focus on improving controls and preventing fraud. "When clients decide to split a professional service, it paves the way for change in the competitive landscape, and that's what's happening in audit at the moment," said Fiona Czerniawska, co-founder of Source Global, which surveyed 150 executives in the U.S. and U.K who are involved in the selection of external auditors. "People are already starting to act on this." Fifty-nine percent of executives said technology firms would gather data faster and at a lower cost than external accounting and audit firms, the report said. Sixty-one percent said technology firms would do a better job of automating financial processes than these firms, according to the report.


LS-Tree: Model Interpretation When the Data Are Linguistic

arXiv.org Machine Learning

We study the problem of interpreting trained classification models in the setting of linguistic data sets. Leveraging a parse tree, we propose to assign least-squares based importance scores to each word of an instance by exploiting syntactic constituency structure. We establish an axiomatic characterization of these importance scores by relating them to the Banzhaf value in coalitional game theory. Based on these importance scores, we develop a principled method for detecting and quantifying interactions between words in a sentence. We demonstrate that the proposed method can aid in interpretability and diagnostics for several widely-used language models.


Non-Monotonic Sequential Text Generation

arXiv.org Machine Learning

Standard sequential generation methods assume a pre-specified generation order, such as text generation methods which generate words from left to right. In this work, we propose a framework for training models of text generation that operate in non-monotonic orders; the model directly learns good orders, without any additional annotation. Our framework operates by generating a word at an arbitrary position, and then recursively generating words to its left and then words to its right, yielding a binary tree. Learning is framed as imitation learning, including a coaching method which moves from imitating an oracle to reinforcing the policy's own preferences. Experimental results demonstrate that using the proposed method, it is possible to learn policies which generate text without pre-specifying a generation order, while achieving competitive performance with conventional left-to-right generation.


Introduction to StanfordNLP with Python Implementation

#artificialintelligence

A common challenge I came across while learning Natural Language Processing (NLP) โ€“ can we build models for non-English languages? The answer has been no for quite a long time. Each language has its own grammatical patterns and linguistic nuances. I could barely contain my excitement when I read the news last week. The authors claimed StanfordNLP could support more than 53 human languages!


StanfordNLP

#artificialintelligence

StanfordNLP is the combination of the software package used by the Stanford team in the CoNLL 2018 Shared Task on Universal Dependency Parsing, and the group's official Python interface to the Stanford CoreNLP software. Aside from the functions it inherits from CoreNLP, it contains tools to convert a string of text to lists of sentences and words, generate base forms of those words, their parts of speech and morphological features, and a syntactic structure that is designed to be parallel among more than 70 languages. This package is built with highly accurate neural network components that enables efficient training and evaluation with your own annotated data. The modules are built on top of PyTorch. To see StanfordNLP's neural pipeline in action, you can launch the Python interactive interpreter, and try the following commands At the end, you should be able to see the dependency parse of the first sentence in the example.


The Latest: Trump Says He's 'Set the Stage' for Wall Action

U.S. News

The DEA has reported that land ports of entry are the primary means for getting drugs into the country, not stretches of the border without barriers. The agency says the most common trafficking technique by transnational criminal organizations is to hide drugs in passenger vehicles or tractor-trailers.