1,721,028 research outputs found
Evaluating neural network explanation methods using hybrid documents and morphosyntactic agreement
Full text linkThe behavior of deep neural networks (DNNs) is hard to understand. This makes it necessary to explore post hoc explanation methods. We conduct the first comprehensive evaluation of explanation methods for NLP. To this end, we design two novel evaluation paradigms that cover two important classes of NLP problems: small context and large context problems. Both paradigms require no manual annotation and are therefore broadly applicable.We also introduce LIMSSE, an explanation method inspired by LIME that is designed for NLP. We show empirically that LIMSSE, LRP and DeepLIFT are the mosteffective explanation methods and recommend them for explaining DNNs in NLP
Probabilistic FastText for Multi-Sense Word Embeddings
Full text linkWe introduce Probabilistic FastText, a new model for word embeddings that can capture multiple word senses, sub-word structure, and uncertainty information. In particular, we represent each word with a Gaussian mixture density, where the mean of a mixture component is given by the sum of n-grams. This representation allows the model to share statistical strength across sub-word structures (e.g. Latin roots), producing accurate representations of rare, misspelt, or even unseen words. Moreover, each component of the mixture can capture a different word sense. Probabilistic FastText outperforms both FastText, which has no probabilistic model, and dictionary-level probabilistic embeddings, which do not incorporate subword structures, on several word-similarity benchmarks, including English RareWord and foreign language datasets. We also achieve state-of-art performance on benchmarks that measure ability to discern different meanings. Thus, the proposed model is the first to achieve multi-sense representations while having enriched semantics on rare words
Explicit Retrofitting of Distributional Word Vectors
Full text linkSemantic specialization of distributional word vectors, referred to as retrofitting, is a process of fine-tuning word vectors using external lexical knowledge in order to better embed some semantic relation. Existing retrofitting models integrate linguistic constraints directly into learning objectives and, consequently, specialize only the vectors of words from the constraints. In this work, in contrast, we transform external lexico-semantic relations into training examples which we use to learn an explicit retrofitting model (ER). The ER model allows us to learn a global specialization function and specialize the vectors of words unobserved in the training data as well. We report large gains over original distributional vector spaces in (1) intrinsic word similarity evaluation and on (2) two downstream tasks -- lexical simplification and dialog state tracking. Finally, we also successfully specialize vector spaces of new languages (i.e., unseen in the training data) by coupling ER with shared multilingual distributional vector spaces
Learning how to actively learn:a deep imitation learning approach
No full textHeuristic-based active learning (AL) methods are limited when the data distribution of the underlying learning problems vary. We introduce a methodthat learns an AL policy using imitation learning (IL). Our IL-based approachmakes use of an efficient and effective algorithmic expert, which provides thepolicy learner with good actions in the encountered AL situations. The AL strategy is then learned with a feedforward network, mapping situations to mostinformative query datapoints. We evaluate our method on two different tasks: text classification and named entity recognition. Experimental results show that our IL-based AL strategy is more effective than strong previous methods usingheuristics and reinforcement learning
Numeracy for language models: Evaluating and improving their ability to predict numbers
Full text linkNumeracy is the ability to understand and work with numbers. It is a necessary skill for composing and understanding documents in clinical, scientific, and other technical domains. In this paper, we explore different strategies for modelling numerals with language models, such as memorisation and digit-by-digit composition, and propose a novel neural architecture that uses a continuous probability density function to model numerals from an open vocabulary. Our evaluation on clinical and scientific datasets shows that using hierarchical models to distinguish numerals from words improves a perplexity metric on the subset of numerals by 2 and 4 orders of magnitude, respectively, over non-hierarchical models. A combination of strategies can further improve perplexity. Our continuous probability density function model reduces mean absolute percentage errors by 18% and 54% in comparison to the second best strategy for each dataset, respectively
Adaptive knowledge sharing in multi-task learning:improving low-resource neural machine translation
Full text linkNeural Machine Translation (NMT) is notorious for its need for large amounts ofbilingual data. An effective approach to compensate for this requirement is Multi-Task Learning (MTL) to leverage different linguistic resources as a source of inductive bias. Current MTL architectures are based on the SEQ2SEQ transduction, and (partially) share different components of the models among the tasks. However, this MTL approach often suffers from task interference, and is not able to fully capture commonalities among subsets of tasks. We address this issue by extending the recurrent units with multiple blocks along with a trainable routing network. The routing network enables adaptive collaboration by dynamic sharing of blocks conditioned on the task at hand, input, and model state. Empirical evaluation of two low-resource translation tasks, English to Vietnamese and Farsi, show +1 BLEU score improvements compared to strong baselines
Open SDP
No full textThe original SDP 2014 and 2015 data collections were made available under task-specific ‘evaluation’ licenses to registered SemEval participants. In mid-2016, all original data has been bundled with system submissions, supporting software, an additional SDP-style collection of semantic dependency graphs, and additional background material (from which some of the SDP target representations were derived) for release through the Linguistic Data Consortium (with LDC catalogue number LDC2016 T10).
One of the four English target representations (viz. DM) and the entire Czech data (in the PSD target representation) are not derivative of LDC-licensed annotations and, thus, can be made available for direct download (Open SDP; version 1.1; April 2016) under a more permissive licensing scheme, viz. the Creative Common Attribution-NonCommercial-ShareAlike license. This package also includes some ‘richer’ meaning representations from which the English bi-lexical DM graphs derive, viz. scope-underspecified logical forms and more abstract, non-lexicalized ‘semantic networks’. The latter of these are formally (if not linguistically) similar to Abstract Meaning Representation (AMR) and are available in a range of serializations, including in AMR-like syntax.
Please use the following bibliographic reference for the SDP 2016 data:
@string{C:LREC = {{I}nternational {C}onference on
{L}anguage {R}esources and {E}valuation}}
@string{LREC:16 = {Proceedings of the 10th } # C:LREC}
@string{L:LREC:16 = {Portoro\v{z}, Slovenia}}
@inproceedings{Oep:Kuh:Miy:16,
author = {Oepen, Stephan and Kuhlmann, Marco and Miyao, Yusuke
and Zeman, Daniel and Cinkov{\'a}, Silvie
and Flickinger, Dan and Haji\v{c}, Jan
and Ivanova, Angelina and Ure\v{s}ov{\'a}, Zde\v{n}ka},
title = {Towards Comparability of Linguistic Graph Banks for Semantic Parsing},
booktitle = LREC:16
year = 2016,
address = L:LREC:16,
pages = {3991--3995}
Open SDP 1.2
No full textThe original SDP 2014 and 2015 data collections were made available under task-specific ‘evaluation’ licenses to registered SemEval participants. In mid-2016, all original data has been bundled with system submissions, supporting software, an additional SDP-style collection of semantic dependency graphs, and additional background material (from which some of the SDP target representations were derived) for release through the Linguistic Data Consortium (with LDC catalogue number LDC2016 T10).
One of the four English target representations (viz. DM) and the entire Czech data (in the PSD target representation) are not derivative of LDC-licensed annotations and, thus, can be made available for direct download (Open SDP; version 1.2; January 2017) under a more permissive licensing scheme, viz. the Creative Common Attribution-NonCommercial-ShareAlike license. This package also includes some ‘richer’ meaning representations from which the English bi-lexical DM graphs derive, viz. scope-underspecified logical forms and more abstract, non-lexicalized ‘semantic networks’. The latter of these are formally (if not linguistically) similar to Abstract Meaning Representation (AMR) and are available in a range of serializations, including in AMR-like syntax.
Version 1.1 was released April 2016. Version 1.2 adds the 2015 Turku system, which was accidentally left out from version 1.1.
Please use the following bibliographic reference for the SDP 2016 data:
@string{C:LREC = {{I}nternational {C}onference on
{L}anguage {R}esources and {E}valuation}}
@string{LREC:16 = {Proceedings of the 10th } # C:LREC}
@string{L:LREC:16 = {Portoro\v{z}, Slovenia}}
@inproceedings{Oep:Kuh:Miy:16,
author = {Oepen, Stephan and Kuhlmann, Marco and Miyao, Yusuke
and Zeman, Daniel and Cinkov{\'a}, Silvie
and Flickinger, Dan and Haji\v{c}, Jan
and Ivanova, Angelina and Ure\v{s}ov{\'a}, Zde\v{n}ka},
title = {Towards Comparability of Linguistic Graph Banks for Semantic Parsing},
booktitle = LREC:16
year = 2016,
address = L:LREC:16,
pages = {3991--3995}
Graph-to-sequence learning using Gated Graph Neural Networks
Full text linkMany NLP applications can be framed as a graph-to-sequence learning problem.Previous work proposing neural architectures on this setting obtained promisingresults compared to grammar-based approaches but still rely on linearisationheuristics and/or standard recurrent networks to achieve the best performance.In this work, we propose a new model that encodes the full structural information contained in the graph. Our architecture couples the recently proposed Gated Graph Neural Networks with an input transformation that allows nodes and edges to have their own hidden representations, while tackling the parameter explosion problem present in previous work. Experimental results show that our model outperforms strong baselines in generation from AMR graphs and syntax-based neural machine translation
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