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 Machine Translation


Modeling Recurrence for Transformer

arXiv.org Artificial Intelligence

Recently, the Transformer model that is based solely on attention mechanisms, has advanced the state-of-the-art on various machine translation tasks. However, recent studies reveal that the lack of recurrence hinders its further improvement of translation capacity. In response to this problem, we propose to directly model recurrence for Transformer with an additional recurrence encoder. In addition to the standard recurrent neural network, we introduce a novel attentive recurrent network to leverage the strengths of both attention and recurrent networks. Experimental results on the widely-used WMT14 English-German and WMT17 Chinese-English translation tasks demonstrate the effectiveness of the proposed approach. Our studies also reveal that the proposed model benefits from a short-cut that bridges the source and target sequences with a single recurrent layer, which outperforms its deep counterpart.


Information Aggregation for Multi-Head Attention with Routing-by-Agreement

arXiv.org Artificial Intelligence

Multi-head attention is appealing for its ability to jointly extract different types of information from multiple representation subspaces. Concerning the information aggregation, a common practice is to use a concatenation followed by a linear transformation, which may not fully exploit the expressiveness of multi-head attention. In this work, we propose to improve the information aggregation for multi-head attention with a more powerful routing-by-agreement algorithm. Specifically, the routing algorithm iteratively updates the proportion of how much a part (i.e. the distinct information learned from a specific subspace) should be assigned to a whole (i.e. the final output representation), based on the agreement between parts and wholes. Experimental results on linguistic probing tasks and machine translation tasks prove the superiority of the advanced information aggregation over the standard linear transformation.


Convolutional Self-Attention Networks

arXiv.org Artificial Intelligence

Self-attention networks (SANs) have drawn increasing interest due to their high parallelization in computation and flexibility in modeling dependencies. SANs can be further enhanced with multi-head attention by allowing the model to attend to information from different representation subspaces. In this work, we propose novel convolutional self-attention networks, which offer SANs the abilities to 1) strengthen dependencies among neighboring elements, and 2) model the interaction between features extracted by multiple attention heads. Experimental results of machine translation on different language pairs and model settings show that our approach outperforms both the strong Transformer baseline and other existing models on enhancing the locality of SANs. Comparing with prior studies, the proposed model is parameter free in terms of introducing no more parameters.


Revisiting Adversarial Autoencoder for Unsupervised Word Translation with Cycle Consistency and Improved Training

arXiv.org Machine Learning

Adversarial training has shown impressive success in learning bilingual dictionary without any parallel data by mapping monolingual embeddings to a shared space. However, recent work has shown superior performance for non-adversarial methods in more challenging language pairs. In this work, we revisit adversarial autoencoder for unsupervised word translation and propose two novel extensions to it that yield more stable training and improved results. Our method includes regularization terms to enforce cycle consistency and input reconstruction, and puts the target encoders as an adversary against the corresponding discriminator. Extensive experimentations with European, non-European and low-resource languages show that our method is more robust and achieves better performance than recently proposed adversarial and non-adversarial approaches.


Differentiable Sampling with Flexible Reference Word Order for Neural Machine Translation

arXiv.org Machine Learning

Despite some empirical success at correcting exposure bias in machine translation, scheduled sampling algorithms suffer from a major drawback: they incorrectly assume that words in the reference translations and in sampled sequences are aligned at each time step. Our new differentiable sampling algorithm addresses this issue by optimizing the probability that the reference can be aligned with the sampled output, based on a soft alignment predicted by the model itself. As a result, the output distribution at each time step is evaluated with respect to the whole predicted sequence. Experiments on IWSLT translation tasks show that our approach improves BLEU compared to maximum likelihood and scheduled sampling baselines. In addition, our approach is simpler to train with no need for sampling schedule and yields models that achieve larger improvements with smaller beam sizes.


Four Ways Evolutionary AI Can Extend AI's Problem-Solving Capacity - Digitally Cognizant

#artificialintelligence

Deep neural networks (DNN) have produced groundbreaking results in many complex applications of AI, such as natural language processing, facial recognition, sentiment analytics and object recognition. For instance, the accuracy of Google's machine translation system improved 60% using a DNN approach. Finding the right network architecture โ€“ that is, the components of the network and how they are instantiated and connected โ€“ is essential to this process. If the architecture is chosen based on history and convenience, the network will not reach its full potential. Much of the recent research in DNNs has focused on designing specialized architectures that excel with specific tasks.


VideoBERT: A Joint Model for Video and Language Representation Learning

arXiv.org Artificial Intelligence

Self-supervised learning has become increasingly important Deep learning can benefit a lot from labeled data [23], to leverage the abundance of unlabeled data available but this is hard to acquire at scale. Consequently there has on platforms like YouTube. Whereas most existing been a lot of recent interest in "self supervised learning", approaches learn low-level representations, we propose a where we train a model on various "proxy tasks", which joint visual-linguistic model to learn high-level features we hope will result in the discovery of features or representations without any explicit supervision. In particular, inspired that can be used in downstream tasks (see e.g., by its recent success in language modeling, we build upon [22]). A wide variety of such proxy tasks have been proposed the BERT model to learn bidirectional joint distributions in the image and video domains. However, most of over sequences of visual and linguistic tokens, derived from these methods focus on low level features (e.g., textures) vector quantization of video data and off-the-shelf speech and short temporal scales (e.g., motion patterns that last a recognition outputs, respectively. We use this model in a second or less). We are interested in discovering high-level number of tasks, including action classification and video semantic features which correspond to actions and events captioning. We show that it can be applied directly to openvocabulary that unfold over longer time scales (e.g.


A Survey of Code-switched Speech and Language Processing

arXiv.org Machine Learning

Code-switching, the alternation of languages within a conversation or utterance, is a common communicative phenomenon that occurs in multilingual communities across the world. This survey reviews computational approaches for code-switched Speech and Natural Language Processing. We motivate why processing code-switched text and speech is essential for building intelligent agents and systems that interact with users in multilingual communities. As code-switching data and resources are scarce, we list what is available in various code-switched language pairs with the language processing tasks they can be used for. We review code-switching research in various Speech and NLP applications, including language processing tools and end-to-end systems. We conclude with future directions and open problems in the field.


Interpreting Black Box Models with Statistical Guarantees

arXiv.org Machine Learning

While many methods for interpreting machine learning models have been proposed, they are frequently ad hoc, difficult to evaluate, and come with no statistical guarantees on the error rate. This is especially problematic in scientific domains, where interpretations must be accurate and reliable. In this paper, we cast black box model interpretation as a hypothesis testing problem. The task is to discover "important" features by testing whether the model prediction is significantly different from what would be expected if the features were replaced with randomly-sampled counterfactuals. We derive a multiple hypothesis testing framework for finding important features that enables control over the false discovery rate. We propose two testing methods, as well as analogs of one-sided and two-sided tests. In simulation, the methods have high power and compare favorably against existing interpretability methods. When applied to vision and language models, the framework selects features that intuitively explain model predictions.


Competence-based Curriculum Learning for Neural Machine Translation

arXiv.org Machine Learning

Current state-of-the-art NMT systems use large neural networks that are not only slow to train, but also often require many heuristics and optimization tricks, such as specialized learning rate schedules and large batch sizes. This is undesirable as it requires extensive hyperparameter tuning. In this paper, we propose a curriculum learning framework for NMT that reduces training time, reduces the need for specialized heuristics or large batch sizes, and results in overall better performance. Our framework consists of a principled way of deciding which training samples are shown to the model at different times during training, based on the estimated difficulty of a sample and the current competence of the model. Filtering training samples in this manner prevents the model from getting stuck in bad local optima, making it converge faster and reach a better solution than the common approach of uniformly sampling training examples. Furthermore, the proposed method can be easily applied to existing NMT models by simply modifying their input data pipelines. We show that our framework can help improve the training time and the performance of both recurrent neural network models and Transformers, achieving up to a 70% decrease in training time, while at the same time obtaining accuracy improvements of up to 2.2 BLEU.