深度神经网络(DNN)容易受到对抗性示例的影响,其中DNN由于含有不可察觉的扰动而被误导为虚假输出。对抗性训练是一种可靠有效的防御方法,可能会大大减少神经网络的脆弱性,并成为强大学习的事实上的标准。尽管许多最近的作品实践了以数据为中心的理念,例如如何生成更好的对抗性示例或使用生成模型来产生额外的培训数据,但我们回顾了模型本身,并从深度特征分布的角度重新审视对抗性的鲁棒性有见地的互补性。在本文中,我们建议分支正交性对抗训练(BORT)获得最先进的性能,仅使用原始数据集用于对抗训练。为了练习我们整合多个正交解决方案空间的设计思想,我们利用一个简单明了的多分支神经网络,可消除对抗性攻击而不会增加推理时间。我们启发提出相应的损耗函数,分支 - 正交丢失,以使多支出模型正交的每个溶液空间。我们分别在CIFAR-10,CIFAR-100和SVHN上评估了我们的方法,分别针对\ ell _ {\ infty}的规范触发尺寸\ epsilon = 8/255。进行了详尽的实验,以表明我们的方法超出了所有最新方法,而无需任何技巧。与所有不使用其他数据进行培训的方法相比,我们的模型在CIFAR-10和CIFAR-100上实现了67.3%和41.5%的鲁棒精度(在最先进的ART上提高了 +7.23%和 +9.07% )。我们还使用比我们的训练组胜过比我们的方法的表现要大得多。我们所有的模型和代码均可在https://github.com/huangd1999/bort上在线获得。
translated by 谷歌翻译
在本文中,我们探讨了构建统一基础模型的可能性,该模型可以适应愿景和仅文本任务。从BERT和VIT开始,我们设计一个由模态特定标记,共享变压器编码器和任务特定的输出头组成的统一变压器。为了有效地预先列车在未配对的图像和文本上联合培训拟议的模型,我们提出了两种新颖的技术:(i)我们使用单独培训的BERT和VIT模型作为老师,并应用知识蒸馏,为关节提供额外的准确的监督信号训练; (ii)我们提出了一种新颖的渐变掩蔽策略,以平衡图像和文本预培训损失的参数更新。我们通过微调它分别在图像分类任务和自然语言理解任务上进行微调,评估联合预训练的变压器。实验表明,由此产生的统一基础变压器令人惊讶地在视觉和仅文本任务中令人惊讶地令人惊讶,并且所提出的知识蒸馏和梯度掩蔽策略可以有效地提升分别训练模型水平的性能。
translated by 谷歌翻译
在点击率(CTR)预测方案中,用户的顺序行为很好地利用来捕获最近文献中的用户兴趣。然而,尽管正在广泛研究,但这些顺序方法仍然存在三个限制。首先,现有方法主要利用对用户行为的注意,这并不总是适用于CTR预测,因为用户经常点击与任何历史行为无关的新产品。其次,在真实场景中,很久以前存在许多具有运营的用户,但最近的次数相对不活跃。因此,难以通过早期行为精确地捕获用户的当前偏好。第三,不同特征子空间中用户历史行为的多个表示主要被忽略。为了解决这些问题,我们提出了一种多互动关注网络(Mian),全面提取各种细粒度特征之间的潜在关系(例如,性别,年龄和用户档案)。具体而言,MIAN包含多交互式层(MIL),其集成了三个本地交互模块,通过顺序行为捕获用户偏好的多个表示,并同时利用细粒度的用户特定的以及上下文信息。此外,我们设计了一个全局交互模块(GIM)来学习高阶交互,平衡多个功能的不同影响。最后,脱机实验结果来自三个数据集,以及在大型推荐系统中的在线A / B测试,展示了我们提出的方法的有效性。
translated by 谷歌翻译
A recent study has shown a phenomenon called neural collapse in that the within-class means of features and the classifier weight vectors converge to the vertices of a simplex equiangular tight frame at the terminal phase of training for classification. In this paper, we explore the corresponding structures of the last-layer feature centers and classifiers in semantic segmentation. Based on our empirical and theoretical analysis, we point out that semantic segmentation naturally brings contextual correlation and imbalanced distribution among classes, which breaks the equiangular and maximally separated structure of neural collapse for both feature centers and classifiers. However, such a symmetric structure is beneficial to discrimination for the minor classes. To preserve these advantages, we introduce a regularizer on feature centers to encourage the network to learn features closer to the appealing structure in imbalanced semantic segmentation. Experimental results show that our method can bring significant improvements on both 2D and 3D semantic segmentation benchmarks. Moreover, our method ranks 1st and sets a new record (+6.8% mIoU) on the ScanNet200 test leaderboard. Code will be available at https://github.com/dvlab-research/Imbalanced-Learning.
translated by 谷歌翻译
When using LiDAR semantic segmentation models for safety-critical applications such as autonomous driving, it is essential to understand and improve their robustness with respect to a large range of LiDAR corruptions. In this paper, we aim to comprehensively analyze the robustness of LiDAR semantic segmentation models under various corruptions. To rigorously evaluate the robustness and generalizability of current approaches, we propose a new benchmark called SemanticKITTI-C, which features 16 out-of-domain LiDAR corruptions in three groups, namely adverse weather, measurement noise and cross-device discrepancy. Then, we systematically investigate 11 LiDAR semantic segmentation models, especially spanning different input representations (e.g., point clouds, voxels, projected images, and etc.), network architectures and training schemes. Through this study, we obtain two insights: 1) We find out that the input representation plays a crucial role in robustness. Specifically, under specific corruptions, different representations perform variously. 2) Although state-of-the-art methods on LiDAR semantic segmentation achieve promising results on clean data, they are less robust when dealing with noisy data. Finally, based on the above observations, we design a robust LiDAR segmentation model (RLSeg) which greatly boosts the robustness with simple but effective modifications. It is promising that our benchmark, comprehensive analysis, and observations can boost future research in robust LiDAR semantic segmentation for safety-critical applications.
translated by 谷歌翻译
Human parsing aims to partition humans in image or video into multiple pixel-level semantic parts. In the last decade, it has gained significantly increased interest in the computer vision community and has been utilized in a broad range of practical applications, from security monitoring, to social media, to visual special effects, just to name a few. Although deep learning-based human parsing solutions have made remarkable achievements, many important concepts, existing challenges, and potential research directions are still confusing. In this survey, we comprehensively review three core sub-tasks: single human parsing, multiple human parsing, and video human parsing, by introducing their respective task settings, background concepts, relevant problems and applications, representative literature, and datasets. We also present quantitative performance comparisons of the reviewed methods on benchmark datasets. Additionally, to promote sustainable development of the community, we put forward a transformer-based human parsing framework, providing a high-performance baseline for follow-up research through universal, concise, and extensible solutions. Finally, we point out a set of under-investigated open issues in this field and suggest new directions for future study. We also provide a regularly updated project page, to continuously track recent developments in this fast-advancing field: https://github.com/soeaver/awesome-human-parsing.
translated by 谷歌翻译
Supervised Deep-Learning (DL)-based reconstruction algorithms have shown state-of-the-art results for highly-undersampled dynamic Magnetic Resonance Imaging (MRI) reconstruction. However, the requirement of excessive high-quality ground-truth data hinders their applications due to the generalization problem. Recently, Implicit Neural Representation (INR) has appeared as a powerful DL-based tool for solving the inverse problem by characterizing the attributes of a signal as a continuous function of corresponding coordinates in an unsupervised manner. In this work, we proposed an INR-based method to improve dynamic MRI reconstruction from highly undersampled k-space data, which only takes spatiotemporal coordinates as inputs. Specifically, the proposed INR represents the dynamic MRI images as an implicit function and encodes them into neural networks. The weights of the network are learned from sparsely-acquired (k, t)-space data itself only, without external training datasets or prior images. Benefiting from the strong implicit continuity regularization of INR together with explicit regularization for low-rankness and sparsity, our proposed method outperforms the compared scan-specific methods at various acceleration factors. E.g., experiments on retrospective cardiac cine datasets show an improvement of 5.5 ~ 7.1 dB in PSNR for extremely high accelerations (up to 41.6-fold). The high-quality and inner continuity of the images provided by INR has great potential to further improve the spatiotemporal resolution of dynamic MRI, without the need of any training data.
translated by 谷歌翻译
Denoising Diffusion Probabilistic Models (DDPMs) are emerging in text-to-speech (TTS) synthesis because of their strong capability of generating high-fidelity samples. However, their iterative refinement process in high-dimensional data space results in slow inference speed, which restricts their application in real-time systems. Previous works have explored speeding up by minimizing the number of inference steps but at the cost of sample quality. In this work, to improve the inference speed for DDPM-based TTS model while achieving high sample quality, we propose ResGrad, a lightweight diffusion model which learns to refine the output spectrogram of an existing TTS model (e.g., FastSpeech 2) by predicting the residual between the model output and the corresponding ground-truth speech. ResGrad has several advantages: 1) Compare with other acceleration methods for DDPM which need to synthesize speech from scratch, ResGrad reduces the complexity of task by changing the generation target from ground-truth mel-spectrogram to the residual, resulting into a more lightweight model and thus a smaller real-time factor. 2) ResGrad is employed in the inference process of the existing TTS model in a plug-and-play way, without re-training this model. We verify ResGrad on the single-speaker dataset LJSpeech and two more challenging datasets with multiple speakers (LibriTTS) and high sampling rate (VCTK). Experimental results show that in comparison with other speed-up methods of DDPMs: 1) ResGrad achieves better sample quality with the same inference speed measured by real-time factor; 2) with similar speech quality, ResGrad synthesizes speech faster than baseline methods by more than 10 times. Audio samples are available at https://resgrad1.github.io/.
translated by 谷歌翻译
The counting task, which plays a fundamental rule in numerous applications (e.g., crowd counting, traffic statistics), aims to predict the number of objects with various densities. Existing object counting tasks are designed for a single object class. However, it is inevitable to encounter newly coming data with new classes in our real world. We name this scenario as \textit{evolving object counting}. In this paper, we build the first evolving object counting dataset and propose a unified object counting network as the first attempt to address this task. The proposed model consists of two key components: a class-agnostic mask module and a class-increment module. The class-agnostic mask module learns generic object occupation prior via predicting a class-agnostic binary mask (e.g., 1 denotes there exists an object at the considering position in an image and 0 otherwise). The class-increment module is used to handle new coming classes and provides discriminative class guidance for density map prediction. The combined outputs of class-agnostic mask module and image feature extractor are used to predict the final density map. When new classes come, we first add new neural nodes into the last regression and classification layers of this module. Then, instead of retraining the model from scratch, we utilize knowledge distilling to help the model remember what have already learned about previous object classes. We also employ a support sample bank to store a small number of typical training samples of each class, which are used to prevent the model from forgetting key information of old data. With this design, our model can efficiently and effectively adapt to new coming classes while keeping good performance on already seen data without large-scale retraining. Extensive experiments on the collected dataset demonstrate the favorable performance.
translated by 谷歌翻译
Crowdsourcing, in which human intelligence and productivity is dynamically mobilized to tackle tasks too complex for automation alone to handle, has grown to be an important research topic and inspired new businesses (e.g., Uber, Airbnb). Over the years, crowdsourcing has morphed from providing a platform where workers and tasks can be matched up manually into one which leverages data-driven algorithmic management approaches powered by artificial intelligence (AI) to achieve increasingly sophisticated optimization objectives. In this paper, we provide a survey presenting a unique systematic overview on how AI can empower crowdsourcing - which we refer to as AI-Empowered Crowdsourcing(AIEC). We propose a taxonomy which divides algorithmic crowdsourcing into three major areas: 1) task delegation, 2) motivating workers, and 3) quality control, focusing on the major objectives which need to be accomplished. We discuss the limitations and insights, and curate the challenges of doing research in each of these areas to highlight promising future research directions.
translated by 谷歌翻译