Developing autonomous vehicles (AVs) helps improve the road safety and traffic efficiency of intelligent transportation systems (ITS). Accurately predicting the trajectories of traffic participants is essential to the decision-making and motion planning of AVs in interactive scenarios. Recently, learning-based trajectory predictors have shown state-of-the-art performance in highway or urban areas. However, most existing learning-based models trained with fixed datasets may perform poorly in continuously changing scenarios. Specifically, they may not perform well in learned scenarios after learning the new one. This phenomenon is called "catastrophic forgetting". Few studies investigate trajectory predictions in continuous scenarios, where catastrophic forgetting may happen. To handle this problem, first, a novel continual learning (CL) approach for vehicle trajectory prediction is proposed in this paper. Then, inspired by brain science, a dynamic memory mechanism is developed by utilizing the measurement of traffic divergence between scenarios, which balances the performance and training efficiency of the proposed CL approach. Finally, datasets collected from different locations are used to design continual training and testing methods in experiments. Experimental results show that the proposed approach achieves consistently high prediction accuracy in continuous scenarios without re-training, which mitigates catastrophic forgetting compared to non-CL approaches. The implementation of the proposed approach is publicly available at https://github.com/BIT-Jack/D-GSM
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Training a Neural Radiance Field (NeRF) without pre-computed camera poses is challenging. Recent advances in this direction demonstrate the possibility of jointly optimising a NeRF and camera poses in forward-facing scenes. However, these methods still face difficulties during dramatic camera movement. We tackle this challenging problem by incorporating undistorted monocular depth priors. These priors are generated by correcting scale and shift parameters during training, with which we are then able to constrain the relative poses between consecutive frames. This constraint is achieved using our proposed novel loss functions. Experiments on real-world indoor and outdoor scenes show that our method can handle challenging camera trajectories and outperforms existing methods in terms of novel view rendering quality and pose estimation accuracy.
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In this paper, we propose an end-to-end Retrieval-Augmented Visual Language Model (REVEAL) that learns to encode world knowledge into a large-scale memory, and to retrieve from it to answer knowledge-intensive queries. REVEAL consists of four key components: the memory, the encoder, the retriever and the generator. The large-scale memory encodes various sources of multimodal world knowledge (e.g. image-text pairs, question answering pairs, knowledge graph triplets, etc) via a unified encoder. The retriever finds the most relevant knowledge entries in the memory, and the generator fuses the retrieved knowledge with the input query to produce the output. A key novelty in our approach is that the memory, encoder, retriever and generator are all pre-trained end-to-end on a massive amount of data. Furthermore, our approach can use a diverse set of multimodal knowledge sources, which is shown to result in significant gains. We show that REVEAL achieves state-of-the-art results on visual question answering and image captioning.
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This work explores an efficient approach to establish a foundational video-text model for tasks including open-vocabulary video classification, text-to-video retrieval, video captioning and video question-answering. We present VideoCoCa that reuses a pretrained image-text contrastive captioner (CoCa) model and adapt it to video-text tasks with minimal extra training. While previous works adapt image-text models with various cross-frame fusion modules (for example, cross-frame attention layer or perceiver resampler) and finetune the modified architecture on video-text data, we surprisingly find that the generative attentional pooling and contrastive attentional pooling layers in the image-text CoCa design are instantly adaptable to ``flattened frame embeddings'', yielding a strong zero-shot transfer baseline for many video-text tasks. Specifically, the frozen image encoder of a pretrained image-text CoCa takes each video frame as inputs and generates \(N\) token embeddings per frame for totally \(T\) video frames. We flatten \(N \times T\) token embeddings as a long sequence of frozen video representation and apply CoCa's generative attentional pooling and contrastive attentional pooling on top. All model weights including pooling layers are directly loaded from an image-text CoCa pretrained model. Without any video or video-text data, VideoCoCa's zero-shot transfer baseline already achieves state-of-the-art results on zero-shot video classification on Kinetics 400/600/700, UCF101, HMDB51, and Charades, as well as zero-shot text-to-video retrieval on MSR-VTT and ActivityNet Captions. We also explore lightweight finetuning on top of VideoCoCa, and achieve strong results on video question-answering (iVQA, MSRVTT-QA, MSVD-QA) and video captioning (MSR-VTT, ActivityNet, Youcook2). Our approach establishes a simple and effective video-text baseline for future research.
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Swarm learning (SL) is an emerging promising decentralized machine learning paradigm and has achieved high performance in clinical applications. SL solves the problem of a central structure in federated learning by combining edge computing and blockchain-based peer-to-peer network. While there are promising results in the assumption of the independent and identically distributed (IID) data across participants, SL suffers from performance degradation as the degree of the non-IID data increases. To address this problem, we propose a generative augmentation framework in swarm learning called SL-GAN, which augments the non-IID data by generating the synthetic data from participants. SL-GAN trains generators and discriminators locally, and periodically aggregation via a randomly elected coordinator in SL network. Under the standard assumptions, we theoretically prove the convergence of SL-GAN using stochastic approximations. Experimental results demonstrate that SL-GAN outperforms state-of-art methods on three real world clinical datasets including Tuberculosis, Leukemia, COVID-19.
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Vision-language foundation models pretrained on large-scale data provide a powerful tool for many visual understanding tasks. Notably, many vision-language models build two encoders (visual and textual) that can map two modalities into the same embedding space. As a result, the learned representations achieve good zero-shot performance on tasks like image classification. However, when there are only a few examples per category, the potential of large vision-language models is often underperformed, mainly due to the gap between a large number of parameters and a relatively small amount of training data. This paper shows that we can significantly improve the performance of few-shot classification by using the category names to initialize the classification head. More interestingly, we can borrow the non-perfect category names, or even names from a foreign language, to improve the few-shot classification performance compared with random initialization. With the proposed category name initialization method, our model obtains the state-of-the-art performance on a number of few-shot image classification benchmarks (e.g., 87.37\% on ImageNet and 96.08\% on Stanford Cars, both using five-shot learning). We also investigate and analyze when the benefit of category names diminishes and how to use distillation to improve the performance of smaller models, providing guidance for future research.
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域的概括旨在学习一个可以很好地概括在看不见的测试数据集(即分布数据集)上的模型,该数据与培训数据集不同。为了解决计算机视觉中的领域概括,我们将损失景观理论引入该领域。具体而言,我们从损失景观的角度从四个方面(包括骨干,正则化,训练范式和学习率)引起了深度学习模型的概括能力。我们通过进行广泛的消融研究和可视化来验证有关NICO ++,PAC和VLCS数据集的提议理论。此外,我们将该理论应用于ECCV 2022 NICO挑战1,并在不使用任何域不变方法的情况下获得第三名。
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激活压缩训练〜(ACT)已被证明是减少训练深神经网络中记忆消耗的一种有希望的方法。但是,现有的ACT工作依赖于在深神经网络(DNN)训练期间寻找最佳的位宽度以减少量化噪声,从而使过程变得复杂且透明。为此,我们提出了一种简单有效的DNN培训方法。我们的方法是由观察结果激励的:\ emph {DNN向后传播主要取决于激活图的低频组分〜(LFC),而不是高频组件〜(HFC)}。它表明激活图的HFC在DNN训练过程中是高度冗余和可压缩的,这激发了我们提出的双重激活精度〜(分裂)。在培训期间,分裂估计激活图的LFC和HFC,并将HFC压缩到低精度副本中以消除冗余。这可以大大减少记忆消耗,而不会对DNN向后传播的精度产生负面影响。这样,部门可以实现可比的表现与正常培训。三个基准数据集的实验结果表明,在记忆消耗,模型准确性和跑步速度方面,分裂的表现优于最先进的基线方法。
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机器学习的普及增加了不公平模型的风险,该模型被部署在高级应用程序中,例如司法系统,药物/疫苗接种设计和医学诊断。尽管有有效的方法可以从头开始训练公平模型,但如何自动揭示和解释受过训练的模型的不公平仍然是一项艰巨的任务。以可解释的方式揭示机器学习模型的不公平是朝着公平和值得信赖的AI迈出的关键一步。在本文中,我们系统地解决了通过挖掘可解释的证据(Rumie)来揭示不公平模型的新任务。关键思想是以一组模型区分的数据实例的形式找到可靠的证据。为了使证据可以解释,我们还找到了一组人为理解的关键属性和决策规则,这些属性和决策规则表征了歧视的数据实例,并将其与其他非歧视数据区分开来。正如在许多现实世界数据集上进行的广泛实验所证明的那样,我们的方法找到了高度可解释和可靠的证据,可以有效揭示受过训练的模型的不公平性。此外,它比所有基线方法更可扩展。
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最近,诸如Interovae和S-Introvae之类的内省模型在图像生成和重建任务方面表现出色。内省模型的主要特征是对VAE的对抗性学习,编码器试图区分真实和假(即合成)图像。但是,由于有效度量标准无法评估真实图像和假图像之间的差异,因此后塌陷和消失的梯度问题仍然存在,从而降低了合成图像的保真度。在本文中,我们提出了一种称为对抗性相似性距离内省变化自动编码器(AS-Introvae)的新变体。我们理论上分析了消失的梯度问题,并使用2-Wasserstein距离和内核技巧构建了新的对抗相似性距离(AS-cantance)。随着重量退火,AS-Introvae能够产生稳定和高质量的图像。通过每批次尝试转换图像,以使其更好地适合潜在空间中的先前分布,从而解决了后塌陷问题。与每个图像方法相比,该策略促进了潜在空间中更多样化的分布,从而使我们的模型能够产生巨大的多样性图像。基准数据集的全面实验证明了AS-Introvae对图像生成和重建任务的有效性。
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