2,485 research outputs found
Multi-space Variational Encoder-Decoders for Semi-supervised Labeled Sequence Transduction
Labeled sequence transduction is a task of transforming one sequence into
another sequence that satisfies desiderata specified by a set of labels. In
this paper we propose multi-space variational encoder-decoders, a new model for
labeled sequence transduction with semi-supervised learning. The generative
model can use neural networks to handle both discrete and continuous latent
variables to exploit various features of data. Experiments show that our model
provides not only a powerful supervised framework but also can effectively take
advantage of the unlabeled data. On the SIGMORPHON morphological inflection
benchmark, our model outperforms single-model state-of-art results by a large
margin for the majority of languages.Comment: Accepted by ACL 201
Advances in Joint CTC-Attention based End-to-End Speech Recognition with a Deep CNN Encoder and RNN-LM
We present a state-of-the-art end-to-end Automatic Speech Recognition (ASR)
model. We learn to listen and write characters with a joint Connectionist
Temporal Classification (CTC) and attention-based encoder-decoder network. The
encoder is a deep Convolutional Neural Network (CNN) based on the VGG network.
The CTC network sits on top of the encoder and is jointly trained with the
attention-based decoder. During the beam search process, we combine the CTC
predictions, the attention-based decoder predictions and a separately trained
LSTM language model. We achieve a 5-10\% error reduction compared to prior
systems on spontaneous Japanese and Chinese speech, and our end-to-end model
beats out traditional hybrid ASR systems.Comment: Accepted for INTERSPEECH 201
Copy mechanism and tailored training for character-based data-to-text generation
In the last few years, many different methods have been focusing on using
deep recurrent neural networks for natural language generation. The most widely
used sequence-to-sequence neural methods are word-based: as such, they need a
pre-processing step called delexicalization (conversely, relexicalization) to
deal with uncommon or unknown words. These forms of processing, however, give
rise to models that depend on the vocabulary used and are not completely
neural.
In this work, we present an end-to-end sequence-to-sequence model with
attention mechanism which reads and generates at a character level, no longer
requiring delexicalization, tokenization, nor even lowercasing. Moreover, since
characters constitute the common "building blocks" of every text, it also
allows a more general approach to text generation, enabling the possibility to
exploit transfer learning for training. These skills are obtained thanks to two
major features: (i) the possibility to alternate between the standard
generation mechanism and a copy one, which allows to directly copy input facts
to produce outputs, and (ii) the use of an original training pipeline that
further improves the quality of the generated texts.
We also introduce a new dataset called E2E+, designed to highlight the
copying capabilities of character-based models, that is a modified version of
the well-known E2E dataset used in the E2E Challenge. We tested our model
according to five broadly accepted metrics (including the widely used BLEU),
showing that it yields competitive performance with respect to both
character-based and word-based approaches.Comment: ECML-PKDD 2019 (Camera ready version
Paradigm Completion for Derivational Morphology
The generation of complex derived word forms has been an overlooked problem
in NLP; we fill this gap by applying neural sequence-to-sequence models to the
task. We overview the theoretical motivation for a paradigmatic treatment of
derivational morphology, and introduce the task of derivational paradigm
completion as a parallel to inflectional paradigm completion. State-of-the-art
neural models, adapted from the inflection task, are able to learn a range of
derivation patterns, and outperform a non-neural baseline by 16.4%. However,
due to semantic, historical, and lexical considerations involved in
derivational morphology, future work will be needed to achieve performance
parity with inflection-generating systems.Comment: EMNLP 201
Improved training of end-to-end attention models for speech recognition
Sequence-to-sequence attention-based models on subword units allow simple
open-vocabulary end-to-end speech recognition. In this work, we show that such
models can achieve competitive results on the Switchboard 300h and LibriSpeech
1000h tasks. In particular, we report the state-of-the-art word error rates
(WER) of 3.54% on the dev-clean and 3.82% on the test-clean evaluation subsets
of LibriSpeech. We introduce a new pretraining scheme by starting with a high
time reduction factor and lowering it during training, which is crucial both
for convergence and final performance. In some experiments, we also use an
auxiliary CTC loss function to help the convergence. In addition, we train long
short-term memory (LSTM) language models on subword units. By shallow fusion,
we report up to 27% relative improvements in WER over the attention baseline
without a language model.Comment: submitted to Interspeech 201
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