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Mu Li 0003

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7 papers

1 author row

ICLR Conference 2023 Conference Paper

AIM: Adapting Image Models for Efficient Video Action Recognition

Taojiannan Yang
Yi Zhu 0001
Yusheng Xie
Aston Zhang
Chen Chen 0001
Mu Li 0003

Recent vision transformer based video models mostly follow the ``image pre-training then finetuning" paradigm and have achieved great success on multiple video benchmarks. However, fully finetuning such a video model could be computationally expensive and unnecessary, given the pre-trained image transformer models have demonstrated exceptional transferability. In this work, we propose a novel method to Adapt pre-trained Image Models (AIM) for efficient video understanding. By freezing the pre-trained image model and adding a few lightweight Adapters, we introduce spatial adaptation, temporal adaptation and joint adaptation to gradually equip an image model with spatiotemporal reasoning capability. We show that our proposed AIM can achieve competitive or even better performance than prior arts with substantially fewer tunable parameters on four video action recognition benchmarks. Thanks to its simplicity, our method is also generally applicable to different image pre-trained models, which has the potential to leverage more powerful image foundation models in the future. The project webpage is https://adapt-image-models.github.io/.

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ICLR Conference 2023 Conference Paper

Automatic Chain of Thought Prompting in Large Language Models

Zhuosheng Zhang 0001
Aston Zhang
Mu Li 0003
Alexander J. Smola

Large Language Models (LLMs) can carry out complex reasoning tasks by generating intermediate reasoning steps. These steps are triggered by what is called chain-of-thought (CoT) prompting, which comes in two flavors: one leverages a simple prompt like "Let’s think step by step" to facilitate step-by-step reasoning before answering a question (Zero-Shot-CoT). The other uses manual demonstrations, each composed of a question and a reasoning chain that leads to an answer (Manual-CoT). Unfortunately, the superior performance of the latter strategy crucially hinges on manually generating task-specific demonstrations. This makes it far less scalable and more dependent on the talent of the CoT engineer. We show that such manual efforts may be eliminated by leveraging LLMs to generate the reasoning chains on its own. Since these generated chains often come with mistakes we propose a number of mitigation strategies. Our proposed Auto-CoT method automaticaly samples diverse questions and we perform post-processing quality control to generate usable reasoning chains from Zero-Shot-CoT. On ten public benchmark reasoning tasks, Auto-CoT performs on par with Manual-CoT without the need for human intervention. Code is available at https://github.com/amazon-research/auto-cot.

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ICLR Conference 2023 Conference Paper

Learning Multimodal Data Augmentation in Feature Space

Zichang Liu
Zhiqiang Tang 0001
Xingjian Shi
Aston Zhang
Mu Li 0003
Anshumali Shrivastava
Andrew Gordon Wilson

The ability to jointly learn from multiple modalities, such as text, audio, and visual data, is a defining feature of intelligent systems. While there have been promising advances in designing neural networks to harness multimodal data, the enormous success of data augmentation currently remains limited to single-modality tasks like image classification. Indeed, it is particularly difficult to augment each modality while preserving the overall semantic structure of the data; for example, a caption may no longer be a good description of an image after standard augmentations have been applied, such as translation. Moreover, it is challenging to specify reasonable transformations that are not tailored to a particular modality. In this paper, we introduce LeMDA, Learning Multimodal Data Augmentation, an easy-to-use method that automatically learns to jointly augment multimodal data in feature space, with no constraints on the identities of the modalities or the relationship between modalities. We show that LeMDA can (1) profoundly improve the performance of multimodal deep learning architectures, (2) apply to combinations of modalities that have not been previously considered, and (3) achieve state-of-the-art results on a wide range of applications comprised of image, text, and tabular data.

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ICLR Conference 2023 Conference Paper

Parameter-Efficient Fine-Tuning Design Spaces

Jiaao Chen
Aston Zhang
Xingjian Shi
Mu Li 0003
Alexander J. Smola
Diyi Yang

Parameter-efficient fine-tuning aims to achieve comparable performances of fine-tuning with much fewer trainable parameters. Recently, various tuning strategies (e.g., Adapters, Prefix Tuning, BitFit, and LoRA) have been proposed. However, their designs are hand-crafted separately, and it remains unclear whether certain design patterns exist for parameter-efficient fine-tuning. Thus, we present a parameter-efficient fine-tuning design paradigm and discover design patterns that are applicable to different experimental settings. Instead of focusing on designing another individual tuning strategy, we introduce parameter-efficient fine-tuning design spaces that parameterize tuning structures and tuning strategies. Specifically, any design space is characterized by four components: layer grouping, trainable parameter allocation, tunable groups, and strategy assignment. Our comprehensive empirical study leads to the discovery of design patterns: (i) grouping layers in a spindle pattern, (ii) uniformly allocating the number of trainable parameters to layers, (ii) tuning all the groups, and (iv) tuning different groups with proper strategies. Our discovered design patterns result in new parameter-efficient fine-tuning methods. Experiments show that these methods consistently outperform investigated parameter-efficient fine-tuning strategies across different backbone models and different tasks in natural language processing.

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ICML Conference 2023 Conference Paper

XTab: Cross-table Pretraining for Tabular Transformers

Bingzhao Zhu
Xingjian Shi
Nick Erickson
Mu Li 0003
George Karypis
Mahsa Shoaran

The success of self-supervised learning in computer vision and natural language processing has motivated pretraining methods on tabular data. However, most existing tabular self-supervised learning models fail to leverage information across multiple data tables and cannot generalize to new tables. In this work, we introduce XTab, a framework for cross-table pretraining of tabular transformers on datasets from various domains. We address the challenge of inconsistent column types and quantities among tables by utilizing independent featurizers and using federated learning to pretrain the shared component. Tested on 84 tabular prediction tasks from the OpenML-AutoML Benchmark (AMLB), we show that (1) XTab consistently boosts the generalizability, learning speed, and performance of multiple tabular transformers, (2) by pretraining FT-Transformer via XTab, we achieve superior performance than other state-of-the-art tabular deep learning models on various tasks such as regression, binary, and multiclass classification.

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ICML Conference 2022 Conference Paper

Partial and Asymmetric Contrastive Learning for Out-of-Distribution Detection in Long-Tailed Recognition

Haotao Wang
Aston Zhang
Yi Zhu 0001
Shuai Zheng 0004
Mu Li 0003
Alexander J. Smola
Zhangyang Wang

Existing out-of-distribution (OOD) detection methods are typically benchmarked on training sets with balanced class distributions. However, in real-world applications, it is common for the training sets to have long-tailed distributions. In this work, we first demonstrate that existing OOD detection methods commonly suffer from significant performance degradation when the training set is long-tail distributed. Through analysis, we posit that this is because the models struggle to distinguish the minority tail-class in-distribution samples, from the true OOD samples, making the tail classes more prone to be falsely detected as OOD. To solve this problem, we propose Partial and Asymmetric Supervised Contrastive Learning (PASCL), which explicitly encourages the model to distinguish between tail-class in-distribution samples and OOD samples. To further boost in-distribution classification accuracy, we propose Auxiliary Branch Finetuning, which uses two separate branches of BN and classification layers for anomaly detection and in-distribution classification, respectively. The intuition is that in-distribution and OOD anomaly data have different underlying distributions. Our method outperforms previous state-of-the-art method by $1. 29%$, $1. 45%$, $0. 69%$ anomaly detection false positive rate (FPR) and $3. 24%$, $4. 06%$, $7. 89%$ in-distribution classification accuracy on CIFAR10-LT, CIFAR100-LT, and ImageNet-LT, respectively. Code and pre-trained models are available at https: //github. com/amazon-research/long-tailed-ood-detection.

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ICML Conference 2022 Conference Paper

Removing Batch Normalization Boosts Adversarial Training

Haotao Wang
Aston Zhang
Shuai Zheng 0004
Xingjian Shi
Mu Li 0003
Zhangyang Wang

Adversarial training (AT) defends deep neural networks against adversarial attacks. One challenge that limits its practical application is the performance degradation on clean samples. A major bottleneck identified by previous works is the widely used batch normalization (BN), which struggles to model the different statistics of clean and adversarial training samples in AT. Although the dominant approach is to extend BN to capture this mixture of distribution, we propose to completely eliminate this bottleneck by removing all BN layers in AT. Our normalizer-free robust training (NoFrost) method extends recent advances in normalizer-free networks to AT for its unexplored advantage on handling the mixture distribution challenge. We show that NoFrost achieves adversarial robustness with only a minor sacrifice on clean sample accuracy. On ImageNet with ResNet50, NoFrost achieves $74. 06%$ clean accuracy, which drops merely $2. 00%$ from standard training. In contrast, BN-based AT obtains $59. 28%$ clean accuracy, suffering a significant $16. 78%$ drop from standard training. In addition, NoFrost achieves a $23. 56%$ adversarial robustness against PGD attack, which improves the $13. 57%$ robustness in BN-based AT. We observe better model smoothness and larger decision margins from NoFrost, which make the models less sensitive to input perturbations and thus more robust. Moreover, when incorporating more data augmentations into NoFrost, it achieves comprehensive robustness against multiple distribution shifts. Code and pre-trained models are public at https: //github. com/amazon-research/normalizer-free-robust-training.

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