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Collaborating Authors

 Peng, Bowen


DeMo: Decoupled Momentum Optimization

arXiv.org Artificial Intelligence

Training large neural networks typically requires sharing gradients between accelerators through specialized high-speed interconnects. Drawing from the signal processing principles of frequency decomposition and energy compaction, we demonstrate that synchronizing full optimizer states and model parameters during training is unnecessary. By decoupling momentum updates and allowing controlled divergence in optimizer states across accelerators, we achieve improved convergence compared to state-of-the-art optimizers. We introduce {\textbf{De}}coupled {\textbf{Mo}}mentum (DeMo), a fused optimizer and data parallel algorithm that reduces inter-accelerator communication requirements by several orders of magnitude. This enables training of large neural networks even with limited network bandwidth and heterogeneous hardware. Our method is topology-agnostic and architecture-independent and supports scalable clock-synchronous distributed training with negligible compute and memory overhead. Empirical results show that models trained with DeMo match or exceed the performance of equivalent models trained with AdamW, while eliminating the need for high-speed interconnects when pre-training large scale foundation models. An open source reference PyTorch implementation is published on GitHub at https://github.com/bloc97/DeMo


S$^4$ST: A Strong, Self-transferable, faSt, and Simple Scale Transformation for Transferable Targeted Attack

arXiv.org Artificial Intelligence

Transferable targeted adversarial attacks (TTAs) against deep neural networks have been proven significantly more challenging than untargeted ones, yet they remain relatively underexplored. This paper sheds new light on performing highly efficient yet transferable targeted attacks leveraging the simple gradient-based baseline. Our research underscores the critical importance of image transformations within gradient calculations, marking a shift from the prevalent emphasis on loss functions to address the gradient vanishing problem. Moreover, we have developed two effective blind estimators that facilitate the design of transformation strategies to enhance targeted transferability under black-box conditions. The adversarial examples' self-transferability to geometric transformations has been identified as strongly correlated with their black-box transferability, featuring these basic operations as potent yet overlapped proxies for facilitating targeted transferability. The surrogate self-alignment assessments further highlight simple scaling transformation's exceptional efficacy, which rivals that of most advanced methods. Building on these insights, we introduce a scaling-centered transformation strategy termed Strong, Self-transferable, faSt, and Simple Scale Transformation (S4ST) to enhance transferable targeted attacks. In experiments conducted on the ImageNet-Compatible benchmark dataset, our proposed S4ST attains a SOTA average targeted transfer success rate across various challenging black-box models, outperforming the previous leading method by over 14% while requiring only 25% of the execution time. Additionally, our approach eclipses SOTA attacks considerably and exhibits remarkable effectiveness against real-world APIs. This work marks a significant leap forward in TTAs, revealing the realistic threats they pose and providing a practical generation method for future research.


ARBiBench: Benchmarking Adversarial Robustness of Binarized Neural Networks

arXiv.org Artificial Intelligence

Network binarization exhibits great potential for deployment on resource-constrained devices due to its low computational cost. Despite the critical importance, the security of binarized neural networks (BNNs) is rarely investigated. In this paper, we present ARBiBench, a comprehensive benchmark to evaluate the robustness of BNNs against adversarial perturbations on CIFAR-10 and ImageNet. We first evaluate the robustness of seven influential BNNs on various white-box and black-box attacks. The results reveal that 1) The adversarial robustness of BNNs exhibits a completely opposite performance on the two datasets under white-box attacks. 2) BNNs consistently exhibit better adversarial robustness under black-box attacks. 3) Different BNNs exhibit certain similarities in their robustness performance. Then, we conduct experiments to analyze the adversarial robustness of BNNs based on these insights. Our research contributes to inspiring future research on enhancing the robustness of BNNs and advancing their application in real-world scenarios.


YaRN: Efficient Context Window Extension of Large Language Models

arXiv.org Artificial Intelligence

Rotary Position Embeddings (RoPE) have been shown to effectively encode positional information in transformer-based language models. However, these models fail to generalize past the sequence length they were trained on. We present YaRN (Yet another RoPE extensioN method), a compute-efficient method to extend the context window of such models, requiring 10x less tokens and 2.5x less training steps than previous methods. Using YaRN, we show that LLaMA models can effectively utilize and extrapolate to context lengths much longer than their original pre-training would allow, while also surpassing previous the state-of-the-art at context window extension. In addition, we demonstrate that YaRN exhibits the capability to extrapolate beyond the limited context of a fine-tuning dataset. The models fine-tuned using YaRN has been made available and reproduced online up to 128k context length at https://github.com/jquesnelle/yarn


Learning Invariant Representation via Contrastive Feature Alignment for Clutter Robust SAR Target Recognition

arXiv.org Artificial Intelligence

The deep neural networks (DNNs) have freed the synthetic aperture radar automatic target recognition (SAR ATR) from expertise-based feature designing and demonstrated superiority over conventional solutions. There has been shown the unique deficiency of ground vehicle benchmarks in shapes of strong background correlation results in DNNs overfitting the clutter and being non-robust to unfamiliar surroundings. However, the gap between fixed background model training and varying background application remains underexplored. Inspired by contrastive learning, this letter proposes a solution called Contrastive Feature Alignment (CFA) aiming to learn invariant representation for robust recognition. The proposed method contributes a mixed clutter variants generation strategy and a new inference branch equipped with channel-weighted mean square error (CWMSE) loss for invariant representation learning. In specific, the generation strategy is delicately designed to better attract clutter-sensitive deviation in feature space. The CWMSE loss is further devised to better contrast this deviation and align the deep features activated by the original images and corresponding clutter variants. The proposed CFA combines both classification and CWMSE losses to train the model jointly, which allows for the progressive learning of invariant target representation. Extensive evaluations on the MSTAR dataset and six DNN models prove the effectiveness of our proposal. The results demonstrated that the CFA-trained models are capable of recognizing targets among unfamiliar surroundings that are not included in the dataset, and are robust to varying signal-to-clutter ratios.