Oceania
A New Task: Deriving Semantic Class Targets for the Physical Sciences
Bowles, Micah, Tang, Hongming, Vardoulaki, Eleni, Alexander, Emma L., Luo, Yan, Rudnick, Lawrence, Walmsley, Mike, Porter, Fiona, Scaife, Anna M. M., Slijepcevic, Inigo Val, Segal, Gary
We define deriving semantic class targets as a novel multi-modal task. By doing so, we aim to improve classification schemes in the physical sciences which can be severely abstracted and obfuscating. We address this task for upcoming radio astronomy surveys and present the derived semantic radio galaxy morphology class targets.
Self-Supervised Speech Representation Learning: A Review
Mohamed, Abdelrahman, Lee, Hung-yi, Borgholt, Lasse, Havtorn, Jakob D., Edin, Joakim, Igel, Christian, Kirchhoff, Katrin, Li, Shang-Wen, Livescu, Karen, Maalรธe, Lars, Sainath, Tara N., Watanabe, Shinji
Although supervised deep learning has revolutionized speech and audio processing, it has necessitated the building of specialist models for individual tasks and application scenarios. It is likewise difficult to apply this to dialects and languages for which only limited labeled data is available. Self-supervised representation learning methods promise a single universal model that would benefit a wide variety of tasks and domains. Such methods have shown success in natural language processing and computer vision domains, achieving new levels of performance while reducing the number of labels required for many downstream scenarios. Speech representation learning is experiencing similar progress in three main categories: generative, contrastive, and predictive methods. Other approaches rely on multi-modal data for pre-training, mixing text or visual data streams with speech. Although self-supervised speech representation is still a nascent research area, it is closely related to acoustic word embedding and learning with zero lexical resources, both of which have seen active research for many years. This review presents approaches for self-supervised speech representation learning and their connection to other research areas. Since many current methods focus solely on automatic speech recognition as a downstream task, we review recent efforts on benchmarking learned representations to extend the application beyond speech recognition.
Zoom Out and Observe: News Environment Perception for Fake News Detection
Sheng, Qiang, Cao, Juan, Zhang, Xueyao, Li, Rundong, Wang, Danding, Zhu, Yongchun
Fake news detection is crucial for preventing the dissemination of misinformation on social media. To differentiate fake news from real ones, existing methods observe the language patterns of the news post and "zoom in" to verify its content with knowledge sources or check its readers' replies. However, these methods neglect the information in the external news environment where a fake news post is created and disseminated. The news environment represents recent mainstream media opinion and public attention, which is an important inspiration of fake news fabrication because fake news is often designed to ride the wave of popular events and catch public attention with unexpected novel content for greater exposure and spread. To capture the environmental signals of news posts, we "zoom out" to observe the news environment and propose the News Environment Perception Framework (NEP). For each post, we construct its macro and micro news environment from recent mainstream news. Then we design a popularity-oriented and a novelty-oriented module to perceive useful signals and further assist final prediction. Experiments on our newly built datasets show that the NEP can efficiently improve the performance of basic fake news detectors.
Poisson Reweighted Laplacian Uncertainty Sampling for Graph-based Active Learning
We show that uncertainty sampling is sufficient to achieve exploration versus exploitation in graph-based active learning, as long as the measure of uncertainty properly aligns with the underlying model and the model properly reflects uncertainty in unexplored regions. In particular, we use a recently developed algorithm, Poisson ReWeighted Laplace Learning (PWLL) for the classifier and we introduce an acquisition function designed to measure uncertainty in this graph-based classifier that identifies unexplored regions of the data. We introduce a diagonal perturbation in PWLL which produces exponential localization of solutions, and controls the exploration versus exploitation tradeoff in active learning. We use the well-posed continuum limit of PWLL to rigorously analyze our method, and present experimental results on a number of graph-based image classification problems.
Truncation Sampling as Language Model Desmoothing
Hewitt, John, Manning, Christopher D., Liang, Percy
Long samples of text from neural language models can be of poor quality. Truncation sampling algorithms--like top-$p$ or top-$k$ -- address this by setting some words' probabilities to zero at each step. This work provides framing for the aim of truncation, and an improved algorithm for that aim. We propose thinking of a neural language model as a mixture of a true distribution and a smoothing distribution that avoids infinite perplexity. In this light, truncation algorithms aim to perform desmoothing, estimating a subset of the support of the true distribution. Finding a good subset is crucial: we show that top-$p$ unnecessarily truncates high-probability words, for example causing it to truncate all words but Trump for a document that starts with Donald. We introduce $\eta$-sampling, which truncates words below an entropy-dependent probability threshold. Compared to previous algorithms, $\eta$-sampling generates more plausible long English documents according to humans, is better at breaking out of repetition, and behaves more reasonably on a battery of test distributions.
Concadia: Towards Image-Based Text Generation with a Purpose
Kreiss, Elisa, Fang, Fei, Goodman, Noah D., Potts, Christopher
Current deep learning models often achieve excellent results on benchmark image-to-text datasets but fail to generate texts that are useful in practice. We argue that to close this gap, it is vital to distinguish descriptions from captions based on their distinct communicative roles. Descriptions focus on visual features and are meant to replace an image (often to increase accessibility), whereas captions appear alongside an image to supply additional information. To motivate this distinction and help people put it into practice, we introduce the publicly available Wikipedia-based dataset Concadia consisting of 96,918 images with corresponding English-language descriptions, captions, and surrounding context. Using insights from Concadia, models trained on it, and a preregistered human-subjects experiment with human- and model-generated texts, we characterize the commonalities and differences between descriptions and captions. In addition, we show that, for generating both descriptions and captions, it is useful to augment image-to-text models with representations of the textual context in which the image appeared.
Improving Zero-Shot Multilingual Translation with Universal Representations and Cross-Mappings
The many-to-many multilingual neural machine translation can translate between language pairs unseen during training, i.e., zero-shot translation. Improving zero-shot translation requires the model to learn universal representations and cross-mapping relationships to transfer the knowledge learned on the supervised directions to the zero-shot directions. In this work, we propose the state mover's distance based on the optimal theory to model the difference of the representations output by the encoder. Then, we bridge the gap between the semantic-equivalent representations of different languages at the token level by minimizing the proposed distance to learn universal representations. Besides, we propose an agreement-based training scheme, which can help the model make consistent predictions based on the semantic-equivalent sentences to learn universal cross-mapping relationships for all translation directions. The experimental results on diverse multilingual datasets show that our method can improve consistently compared with the baseline system and other contrast methods. The analysis proves that our method can better align the semantic space and improve the prediction consistency.
Adapting Neural Models with Sequential Monte Carlo Dropout
Carreno-Medrano, Pamela, Kuliฤ, Dana, Burke, Michael
Neural models and policies are now ubiquitous in modern robotics. The prevailing approach to training these follows a two stage process - a large, comprehensive collection of data (often state and action pairs) is used to train a suitable model or policy, which is then frozen and deployed. Unfortunately, this results in models that are unable to adapt to changes in the environment, which is a particular concern in robotics. For example, it would be preferable for a robot dynamics model to handle context dependent kinematic or dynamic properties, or a collaborative robot relying on predictions of human behaviour to adapt to different human abilities or preferences. Many existing adaptive control techniques [1] attempting to tackle this problem rely on carefully considered parametric models, but these may lack the requisite capacity for prediction that is typically associated with neural models. In contrast, meta-learning and adaptive neural control approaches addressing this problem are often quite cumbersome to train and implement. This paper introduces a simple and effective approach to achieve adaptation for neural network models.
Dictionary-Assisted Supervised Contrastive Learning
Wu, Patrick Y., Bonneau, Richard, Tucker, Joshua A., Nagler, Jonathan
Text analysis in the social sciences often involves using specialized dictionaries to reason with abstract concepts, such as perceptions about the economy or abuse on social media. These dictionaries allow researchers to impart domain knowledge and note subtle usages of words relating to a concept(s) of interest. We introduce the dictionary-assisted supervised contrastive learning (DASCL) objective, allowing researchers to leverage specialized dictionaries when fine-tuning pretrained language models. The text is first keyword simplified: a common, fixed token replaces any word in the corpus that appears in the dictionary(ies) relevant to the concept of interest. During fine-tuning, a supervised contrastive objective draws closer the embeddings of the original and keyword-simplified texts of the same class while pushing further apart the embeddings of different classes. The keyword-simplified texts of the same class are more textually similar than their original text counterparts, which additionally draws the embeddings of the same class closer together. Combining DASCL and cross-entropy improves classification performance metrics in few-shot learning settings and social science applications compared to using cross-entropy alone and alternative contrastive and data augmentation methods.
AI art raises questions about copyright
Want to have an impressionist painting of Thai temples in the style of Claude Monet, but you cannot afford to commission an artist? Let artificial intelligence (AI) do the work for you. Then you change your mind and want to have the painting in a surrealistic style. Type what you want in the message field of the AI art-generating program. You get what you wanted.