Frozen pretrained models have become a viable alternative to the pretraining-then-finetuning paradigm for transfer learning. However, with frozen models there are relatively few parameters available for adapting to downstream tasks, which is problematic in computer vision where tasks vary significantly in input/output format and the type of information that is of value. In this paper, we present a study of frozen pretrained models when applied to diverse and representative computer vision tasks, including object detection, semantic segmentation and video action recognition. From this empirical analysis, our work answers the questions of what pretraining task fits best with this frozen setting, how to make the frozen setting more flexible to various downstream tasks, and the effect of larger model sizes. We additionally examine the upper bound of performance using a giant frozen pretrained model with 3 billion parameters (SwinV2-G) and find that it reaches competitive performance on a varied set of major benchmarks with only one shared frozen base network: 60.0 box mAP and 52.2 mask mAP on COCO object detection test-dev, 57.6 val mIoU on ADE20K semantic segmentation, and 81.7 top-1 accuracy on Kinetics-400 action recognition. With this work, we hope to bring greater attention to this promising path of freezing pretrained image models.

We present a unified hard-constraint framework for solving geometrically complex PDEs with neural networks, where the most commonly used Dirichlet, Neumann, and Robin boundary conditions (BCs) are considered. Specifically, we first introduce the "extra fields" from the mixed finite element method to reformulate the PDEs so as to equivalently transform the three types of BCs into linear forms. Based on the reformulation, we derive the general solutions of the BCs analytically, which are employed to construct an ansatz that automatically satisfies the BCs. With such a framework, we can train the neural networks without adding extra loss terms and thus efficiently handle geometrically complex PDEs, alleviating the unbalanced competition between the loss terms corresponding to the BCs and PDEs. We theoretically demonstrate that the "extra fields" can stabilize the training process. Experimental results on real-world geometrically complex PDEs showcase the effectiveness of our method compared with state-of-the-art baselines.

近年来，Experts（MOE）的混合物已成为一种有前途的深度学习技术，可以将模型能力扩展为万亿多个参数，同时通过稀疏计算降低计算成本。虽然MoE开设了一个非常大的模型的新领域，但由于MOE的动态性质与系统的静态平行性/管道层之间的不匹配，因此其数以千计的GPU的实现受到限制。我们提出了Tutel，这是一种具有动态自适应并行性和管道的高度可扩展的堆栈设计和实现。 TUTEL在运行时提供自适应并行性切换和自适应管道，分别达到1.74倍和2.00倍的单MOE层加速度。我们还提出了一种用于MOE通信速度的新颖的二维层次结构算法，该算法的表现超过了2,048 GPU的先前最先前的最新时间。 Tutel汇总了所有技术，最终在16 GPU和2,048 GPU上分别提供了4.96倍和5.75倍的加速度，分别通过Fairseq：Meta的Facebook AI AI研究序列到序列工具Kit（Tutel（Tutel）（Tutel）（Tutel）（现在由Fairseq部分采用）。 Tutel源代码可在公共场所获得：https：//github.com/microsoft/tutel。我们的评估表明，Tutel有效，有效地运行了一个基于现实的MOE模型，名为Swinv2-Moe，建立在Swin Transformer V2上，这是一种最先进的计算机视觉体系结构。在效率方面，Tutel加速了Swinv2-MoE，在FairSeq的训练和推理中分别达到1.55倍和2.11倍的速度。关于有效性，SWINV2-MOE模型在预训练和下游计算机视觉任务（例如可可对象检测）方面都比对应的密度密度模型都达到了卓越的精度，这表明Tutel准备对端到端现实世界模型训练的准备就绪和推理。 Swinv2-Moe在https://github.com/microsoft/swin-transformer中开放。

我们提出了用于将Swin变压器缩放到3亿参数的技术，并使其能够使用高达1,536美元的图像培训1,536美元。通过缩放容量和分辨率，Swin变压器在四个代表视觉基准上设置新记录：84.0％的Top-1在Imagenet-V2图像分类准确度，63.1 / 54.4盒/掩模地图上的Coco对象检测，59.9 Miou在Ade20K语义细分中，在动力学-400视频动作分类上的86.8％的前1个精度。我们的技术通常适用于缩放视觉模型，这尚未广泛探索为NLP语言模型，部分原因是培训和应用中的困难：1）视觉模型经常面临规模的不稳定问题，2）许多下游愿景任务需要高分辨率图像或窗口，并且目前尚不清楚如何有效地将模型在低分辨率上预先培训到更高分辨率。当图像分辨率高时，GPU存储器消耗也是一个问题。为了解决这些问题，我们提出了几种技术，通过使用Swin Transformer作为案例研究来说明：1）归一化技术和缩放的余弦注意力，提高大视觉模型的稳定性; 2）一种日志间隔的连续位置偏置技术，以有效地将在低分辨率图像和窗口预先训练的模型转移到其更高分辨率的对应物。此外，我们分享了我们的关键实施细节，导致GPU内存消耗的大量节省，从而使得用常规GPU培训大型视觉模型可行。使用这些技术和自我监督的预训练，我们成功培训了强大的3B往返变压器模型，并有效地将其转移到涉及高分辨率图像或窗口的各种视觉任务，实现了各种最先进的准确性基准。

This paper presents a new vision Transformer, called Swin Transformer, that capably serves as a general-purpose backbone for computer vision. Challenges in adapting Transformer from language to vision arise from differences between the two domains, such as large variations in the scale of visual entities and the high resolution of pixels in images compared to words in text. To address these differences, we propose a hierarchical Transformer whose representation is computed with Shifted windows. The shifted windowing scheme brings greater efficiency by limiting self-attention computation to non-overlapping local windows while also allowing for cross-window connection. This hierarchical architecture has the flexibility to model at various scales and has linear computational complexity with respect to image size. These qualities of Swin Transformer make it compatible with a broad range of vision tasks, including image classification (87.3 top-1 accuracy on ImageNet-1K) and dense prediction tasks such as object detection (58.7 box AP and 51.1 mask AP on COCO testdev) and semantic segmentation (53.5 mIoU on ADE20K val). Its performance surpasses the previous state-of-theart by a large margin of +2.7 box AP and +2.6 mask AP on COCO, and +3.2 mIoU on ADE20K, demonstrating the potential of Transformer-based models as vision backbones. The hierarchical design and the shifted window approach also prove beneficial for all-MLP architectures. The code and models are publicly available at https://github. com/microsoft/Swin-Transformer.

Modern object detectors rely heavily on rectangular bounding boxes, such as anchors, proposals and the final predictions, to represent objects at various recognition stages. The bounding box is convenient to use but provides only a coarse localization of objects and leads to a correspondingly coarse extraction of object features. In this paper, we present RepPoints (representative points), a new finer representation of objects as a set of sample points useful for both localization and recognition. Given ground truth localization and recognition targets for training, RepPoints learn to automatically arrange themselves in a manner that bounds the spatial extent of an object and indicates semantically significant local areas. They furthermore do not require the use of anchors to sample a space of bounding boxes. We show that an anchor-free object detector based on RepPoints can be as effective as the state-of-the-art anchor-based detection methods, with 46.5 AP and 67.4 AP 50 on the COCO test-dev detection benchmark, using ResNet-101 model. Code is available at https://github.com/microsoft/RepPoints.

We revisit a simple Learning-from-Scratch baseline for visuo-motor control that uses data augmentation and a shallow ConvNet. We find that this baseline has competitive performance with recent methods that leverage frozen visual representations trained on large-scale vision datasets.

Visual Place Recognition is an essential component of systems for camera localization and loop closure detection, and it has attracted widespread interest in multiple domains such as computer vision, robotics and AR/VR. In this work, we propose a faster, lighter and stronger approach that can generate models with fewer parameters and can spend less time in the inference stage. We designed RepVGG-lite as the backbone network in our architecture, it is more discriminative than other general networks in the Place Recognition task. RepVGG-lite has more speed advantages while achieving higher performance. We extract only one scale patch-level descriptors from global descriptors in the feature extraction stage. Then we design a trainable feature matcher to exploit both spatial relationships of the features and their visual appearance, which is based on the attention mechanism. Comprehensive experiments on challenging benchmark datasets demonstrate the proposed method outperforming recent other state-of-the-art learned approaches, and achieving even higher inference speed. Our system has 14 times less params than Patch-NetVLAD, 6.8 times lower theoretical FLOPs, and run faster 21 and 33 times in feature extraction and feature matching. Moreover, the performance of our approach is 0.5\% better than Patch-NetVLAD in Recall@1. We used subsets of Mapillary Street Level Sequences dataset to conduct experiments for all other challenging conditions.

This paper mainly describes the dma submission to the TempoWiC task, which achieves a macro-F1 score of 77.05% and attains the first place in this task. We first explore the impact of different pre-trained language models. Then we adopt data cleaning, data augmentation, and adversarial training strategies to enhance the model generalization and robustness. For further improvement, we integrate POS information and word semantic representation using a Mixture-of-Experts (MoE) approach. The experimental results show that MoE can overcome the feature overuse issue and combine the context, POS, and word semantic features well. Additionally, we use a model ensemble method for the final prediction, which has been proven effective by many research works.

基于深度学习的方法，例如物理知识的神经网络（PINN）和DeepOnets已显示出解决PDE受约束优化（PDECO）问题的希望。但是，现有方法不足以处理对优化目标具有复杂或非线性依赖性的PDE约束。在本文中，我们提出了一个新颖的双层优化框架，以通过将目标和约束的优化解耦来解决挑战。对于内部循环优化，我们采用PINN仅解决PDE约束。对于外循环，我们通过基于隐式函数定理（IFT）使用Broyden的方法来设计一种新颖的方法，该方法对于近似高度级别而言是有效且准确的。我们进一步介绍了高度级计算的理论解释和误差分析。在多个大规模和非线性PDE约束优化问题上进行了广泛的实验表明，与强基础相比，我们的方法可实现最新的结果。