South America
Finding Memo: Extractive Memorization in Constrained Sequence Generation Tasks
Memorization presents a challenge for several constrained Natural Language Generation (NLG) tasks such as Neural Machine Translation (NMT), wherein the proclivity of neural models to memorize noisy and atypical samples reacts adversely with the noisy (web crawled) datasets. However, previous studies of memorization in constrained NLG tasks have only focused on counterfactual memorization, linking it to the problem of hallucinations. In this work, we propose a new, inexpensive algorithm for extractive memorization (exact training data generation under insufficient context) in constrained sequence generation tasks and use it to study extractive memorization and its effects in NMT. We demonstrate that extractive memorization poses a serious threat to NMT reliability by qualitatively and quantitatively characterizing the memorized samples as well as the model behavior in their vicinity. Based on empirical observations, we develop a simple algorithm which elicits non-memorized translations of memorized samples from the same model, for a large fraction of such samples. Finally, we show that the proposed algorithm could also be leveraged to mitigate memorization in the model through finetuning. We have released the code to reproduce our results at https://github.com/vyraun/Finding-Memo.
AACHER: Assorted Actor-Critic Deep Reinforcement Learning with Hindsight Experience Replay
Sehgal, Adarsh, Sehgal, Muskan, La, Hung Manh
Actor learning and critic learning are two components of the outstanding and mostly used Deep Deterministic Policy Gradient (DDPG) reinforcement learning method. Since actor and critic learning plays a significant role in the overall robot's learning, the performance of the DDPG approach is relatively sensitive and unstable as a result. We propose a multi-actor-critic DDPG for reliable actor-critic learning to further enhance the performance and stability of DDPG. This multi-actor-critic DDPG is then integrated with Hindsight Experience Replay (HER) to form our new deep learning framework called AACHER. AACHER uses the average value of multiple actors or critics to substitute the single actor or critic in DDPG to increase resistance in the case when one actor or critic performs poorly. Numerous independent actors and critics can also gain knowledge from the environment more broadly. We implemented our proposed AACHER on goal-based environments: AuboReach, FetchReach-v1, FetchPush-v1, FetchSlide-v1, and FetchPickAndPlace-v1. For our experiments, we used various instances of actor/critic combinations, among which A10C10 and A20C20 were the best-performing combinations. Overall results show that AACHER outperforms the traditional algorithm (DDPG+HER) in all of the actor/critic number combinations that are used for evaluation. When used on FetchPickAndPlace-v1, the performance boost for A20C20 is as high as roughly 3.8 times the success rate in DDPG+HER.
Backdoor Attacks in Federated Learning by Rare Embeddings and Gradient Ensembling
Recent advances in federated learning have demonstrated its promising capability to learn on decentralized datasets. However, a considerable amount of work has raised concerns due to the potential risks of adversaries participating in the framework to poison the global model for an adversarial purpose. This paper investigates the feasibility of model poisoning for backdoor attacks through rare word embeddings of NLP models. In text classification, less than 1% of adversary clients suffices to manipulate the model output without any drop in the performance on clean sentences. For a less complex dataset, a mere 0.1% of adversary clients is enough to poison the global model effectively. We also propose a technique specialized in the federated learning scheme called Gradient Ensemble, which enhances the backdoor performance in all our experimental settings.
Strengthening international cooperation on artificial intelligence
Artificial Intelligence (AI) is a potentially transformational technology that will have broad social, economic, national security, and geopolitical implications for the United States and the world.1 AI is not one particular technology but a general-purpose technology combining software and hardware in systems that enable technologies (machine learning, knowledge representation, and other forms of computerized approximation of human intelligence). This general-purpose nature means that AI could have wide-ranging economic impacts across manufacturing, transportation, health, education, and many other sectors. In 2018, the McKinsey Global Institute estimated that AI could add around 16 percent, or $13 trillion, to global output by 2030.2 Since then COVID-19 has further accelerated the use of AI. While the United States is the world leader in AI, China is catching up fast (and may lead in some areas) and other governments are expanding their own AI capacity. Rather than a zero-sum game, many such efforts can be additive, benefiting global welfare. The U.S. can encourage and support AI efforts that seek to develop and compete on fair terms. Other national policies--China's above all--seek to erect barriers to free and open development of AI, appropriating the benefits for their national champions and applying AI as a geopolitical lever. Such policies could distort the development and benefits of AI for humanity, make the world less secure for the U.S. and allies, and markets less receptive to U.S. products and services. To foster AI policies that support development of beneficial, trustworthy, and robust artificial intelligence will require international engagement by the United States and cooperation among like-minded democracies that are leaders in artificial intelligence.
Precisely the Point: Adversarial Augmentations for Faithful and Informative Text Generation
Wu, Wenhao, Li, Wei, Liu, Jiachen, Xiao, Xinyan, Li, Sujian, Lyu, Yajuan
Though model robustness has been extensively studied in language understanding, the robustness of Seq2Seq generation remains understudied. In this paper, we conduct the first quantitative analysis on the robustness of pre-trained Seq2Seq models. We find that even current SOTA pre-trained Seq2Seq model (BART) is still vulnerable, which leads to significant degeneration in faithfulness and informativeness for text generation tasks. This motivated us to further propose a novel adversarial augmentation framework, namely AdvSeq, for generally improving faithfulness and informativeness of Seq2Seq models via enhancing their robustness. AdvSeq automatically constructs two types of adversarial augmentations during training, including implicit adversarial samples by perturbing word representations and explicit adversarial samples by word swapping, both of which effectively improve Seq2Seq robustness. Extensive experiments on three popular text generation tasks demonstrate that AdvSeq significantly improves both the faithfulness and informativeness of Seq2Seq generation under both automatic and human evaluation settings.
Varifocal Question Generation for Fact-checking
Ousidhoum, Nedjma, Yuan, Zhangdie, Vlachos, Andreas
Fact-checking requires retrieving evidence related to a claim under investigation. The task can be formulated as question generation based on a claim, followed by question answering. However, recent question generation approaches assume that the answer is known and typically contained in a passage given as input, whereas such passages are what is being sought when verifying a claim. In this paper, we present {\it Varifocal}, a method that generates questions based on different focal points within a given claim, i.e.\ different spans of the claim and its metadata, such as its source and date. Our method outperforms previous work on a fact-checking question generation dataset on a wide range of automatic evaluation metrics. These results are corroborated by our manual evaluation, which indicates that our method generates more relevant and informative questions. We further demonstrate the potential of focal points in generating sets of clarification questions for product descriptions.
On Advances in Text Generation from Images Beyond Captioning: A Case Study in Self-Rationalization
Palaskar, Shruti, Bhagia, Akshita, Bisk, Yonatan, Metze, Florian, Black, Alan W, Marasović, Ana
Combining the visual modality with pretrained language models has been surprisingly effective for simple descriptive tasks such as image captioning. More general text generation however remains elusive. We take a step back and ask: How do these models work for more complex generative tasks, i.e. conditioning on both text and images? Are multimodal models simply visually adapted language models, or do they combine they reason jointly over modalities? We investigate these questions in the context of self-rationalization (jointly generating task labels/answers and free-text explanations) of three tasks: (i) visual question answering in VQA-X, (ii) visual commonsense reasoning in VCR, and (iii) visual-textual entailment in e-SNLI-VE. We show that recent unimodal advances, CLIP image representations and scaling of language models, do not consistently improve self-rationalization in multimodal tasks. We find that no single model type works universally best across tasks, datasets, and finetuning data sizes. Our findings motivate the need for novel general backbones approach that move text generation from images and text beyond image captioning.
Improving Tokenisation by Alternative Treatment of Spaces
Gow-Smith, Edward, Madabushi, Harish Tayyar, Scarton, Carolina, Villavicencio, Aline
Tokenisation is the first step in almost all NLP tasks, and state-of-the-art transformer-based language models all use subword tokenisation algorithms to process input text. Existing algorithms have problems, often producing tokenisations of limited linguistic validity, and representing equivalent strings differently depending on their position within a word. We hypothesise that these problems hinder the ability of transformer-based models to handle complex words, and suggest that these problems are a result of allowing tokens to include spaces. We thus experiment with an alternative tokenisation approach where spaces are always treated as individual tokens. Specifically, we apply this modification to the BPE and Unigram algorithms. We find that our modified algorithms lead to improved performance on downstream NLP tasks that involve handling complex words, whilst having no detrimental effect on performance in general natural language understanding tasks. Intrinsically, we find our modified algorithms give more morphologically correct tokenisations, in particular when handling prefixes. Given the results of our experiments, we advocate for always treating spaces as individual tokens as an improved tokenisation method.
Boy, 8, stricken with cerebral palsy takes his first steps thanks to a new exoskeleton
An eight-year-old boy with cerebral palsy has been restricted to a wheelchair all his life, but he recently took his first steps thanks to a robotic exoskeleton designed specifically for children. David Zabala was fitted with a new Atlas 2030 exoskeleton that features mechanical joints that adapt to his motions, allowing him to finally walk freely. The innovation is part of a therapy method being used at a facility in Mexico City, because research shows that allowing paralyzed children the opportunity to walk'not only extends their life expectancy and enhances their physical well-being, but also improves their self-esteem.' The suit helps'to achieve in record time rehabilitation goals' that would take months to achieve with conventional therapies, Guadalupe Maldonado, director of Mexico's Association for People with Cerebral Palsy told AFP. The suit was create by Elena García Armada who won the 2022 European Inventor Award for the innovation.