基于硬件的加速度是促进许多计算密集型数学操作的广泛尝试。本文提出了一个基于FPGA的体系结构来加速卷积操作 - 在许多卷积神经网络模型中出现的复杂且昂贵的计算步骤。我们将设计定为标准卷积操作,打算以边缘-AI解决方案启动产品。该项目的目的是产生一个可以一次处理卷积层的FPGA IP核心。系统开发人员可以使用Verilog HDL作为体系结构的主要设计语言来部署IP核心。实验结果表明,我们在简单的边缘计算FPGA板上合成的单个计算核心可以提供0.224 GOPS。当董事会充分利用时,可以实现4.48 GOP。
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贝叶斯神经网络(BNNS)通过提供认知不确定性的原则概率表示,有望在协变量转移下改善概括。但是,基于重量的BNN通常会在大规模体系结构和数据集的高计算复杂性上挣扎。基于节点的BNN最近被引入了可扩展的替代方案,该替代方案通过将每个隐藏节点乘以潜在的随机变量来诱导认知不确定性,同时学习权重的点刻度。在本文中,我们将这些潜在的噪声变量解释为训练过程中简单和域 - 不合时宜数据扰动的隐式表示,从而产生了由于输入损坏而导致协变量转移的BNN。我们观察到,隐性腐败的多样性取决于潜在变量的熵,并提出了一种直接的方法来增加训练期间这些变量的熵。我们评估了分布外图像分类基准测试的方法,并显示出由于输入扰动而导致的协变量转移下基于节点的BNN的不确定性估计。作为副作用,该方法还提供了针对嘈杂训练标签的鲁棒性。
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Generative models have been widely studied in computer vision. Recently, diffusion models have drawn substantial attention due to the high quality of their generated images. A key desired property of image generative models is the ability to disentangle different attributes, which should enable modification towards a style without changing the semantic content, and the modification parameters should generalize to different images. Previous studies have found that generative adversarial networks (GANs) are inherently endowed with such disentanglement capability, so they can perform disentangled image editing without re-training or fine-tuning the network. In this work, we explore whether diffusion models are also inherently equipped with such a capability. Our finding is that for stable diffusion models, by partially changing the input text embedding from a neutral description (e.g., "a photo of person") to one with style (e.g., "a photo of person with smile") while fixing all the Gaussian random noises introduced during the denoising process, the generated images can be modified towards the target style without changing the semantic content. Based on this finding, we further propose a simple, light-weight image editing algorithm where the mixing weights of the two text embeddings are optimized for style matching and content preservation. This entire process only involves optimizing over around 50 parameters and does not fine-tune the diffusion model itself. Experiments show that the proposed method can modify a wide range of attributes, with the performance outperforming diffusion-model-based image-editing algorithms that require fine-tuning. The optimized weights generalize well to different images. Our code is publicly available at https://github.com/UCSB-NLP-Chang/DiffusionDisentanglement.
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For solving a broad class of nonconvex programming problems on an unbounded constraint set, we provide a self-adaptive step-size strategy that does not include line-search techniques and establishes the convergence of a generic approach under mild assumptions. Specifically, the objective function may not satisfy the convexity condition. Unlike descent line-search algorithms, it does not need a known Lipschitz constant to figure out how big the first step should be. The crucial feature of this process is the steady reduction of the step size until a certain condition is fulfilled. In particular, it can provide a new gradient projection approach to optimization problems with an unbounded constrained set. The correctness of the proposed method is verified by preliminary results from some computational examples. To demonstrate the effectiveness of the proposed technique for large-scale problems, we apply it to some experiments on machine learning, such as supervised feature selection, multi-variable logistic regressions and neural networks for classification.
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Adversarial machine learning has been both a major concern and a hot topic recently, especially with the ubiquitous use of deep neural networks in the current landscape. Adversarial attacks and defenses are usually likened to a cat-and-mouse game in which defenders and attackers evolve over the time. On one hand, the goal is to develop strong and robust deep networks that are resistant to malicious actors. On the other hand, in order to achieve that, we need to devise even stronger adversarial attacks to challenge these defense models. Most of existing attacks employs a single $\ell_p$ distance (commonly, $p\in\{1,2,\infty\}$) to define the concept of closeness and performs steepest gradient ascent w.r.t. this $p$-norm to update all pixels in an adversarial example in the same way. These $\ell_p$ attacks each has its own pros and cons; and there is no single attack that can successfully break through defense models that are robust against multiple $\ell_p$ norms simultaneously. Motivated by these observations, we come up with a natural approach: combining various $\ell_p$ gradient projections on a pixel level to achieve a joint adversarial perturbation. Specifically, we learn how to perturb each pixel to maximize the attack performance, while maintaining the overall visual imperceptibility of adversarial examples. Finally, through various experiments with standardized benchmarks, we show that our method outperforms most current strong attacks across state-of-the-art defense mechanisms, while retaining its ability to remain clean visually.
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Online Class Incremental learning (CIL) is a challenging setting in Continual Learning (CL), wherein data of new tasks arrive in incoming streams and online learning models need to handle incoming data streams without revisiting previous ones. Existing works used a single centroid adapted with incoming data streams to characterize a class. This approach possibly exposes limitations when the incoming data stream of a class is naturally multimodal. To address this issue, in this work, we first propose an online mixture model learning approach based on nice properties of the mature optimal transport theory (OT-MM). Specifically, the centroids and covariance matrices of the mixture model are adapted incrementally according to incoming data streams. The advantages are two-fold: (i) we can characterize more accurately complex data streams and (ii) by using centroids for each class produced by OT-MM, we can estimate the similarity of an unseen example to each class more reasonably when doing inference. Moreover, to combat the catastrophic forgetting in the CIL scenario, we further propose Dynamic Preservation. Particularly, after performing the dynamic preservation technique across data streams, the latent representations of the classes in the old and new tasks become more condensed themselves and more separate from each other. Together with a contraction feature extractor, this technique facilitates the model in mitigating the catastrophic forgetting. The experimental results on real-world datasets show that our proposed method can significantly outperform the current state-of-the-art baselines.
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In this paper we examine the problem of determining demonstration sufficiency for AI agents that learn from demonstrations: how can an AI agent self-assess whether it has received enough demonstrations from an expert to ensure a desired level of performance? To address this problem we propose a novel self-assessment approach based on Bayesian inverse reinforcement learning and value-at-risk to enable agents that learn from demonstrations to compute high-confidence bounds on their performance and use these bounds to determine when they have a sufficient number of demonstrations. We propose and evaluate two definitions of sufficiency: (1) normalized expected value difference, which measures regret with respect to the expert's unobserved reward function, and (2) improvement over a baseline policy. We demonstrate how to formulate high-confidence bounds on both of these metrics. We evaluate our approach in simulation and demonstrate the feasibility of developing an AI system that can accurately evaluate whether it has received sufficient training data to guarantee, with high confidence, that it can match an expert's performance or surpass the performance of a baseline policy within some desired safety threshold.
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3D hand pose estimation from RGB images suffers from the difficulty of obtaining the depth information. Therefore, a great deal of attention has been spent on estimating 3D hand pose from 2D hand joints. In this paper, we leverage the advantage of spatial-temporal Graph Convolutional Neural Networks and propose LG-Hand, a powerful method for 3D hand pose estimation. Our method incorporates both spatial and temporal dependencies into a single process. We argue that kinematic information plays an important role, contributing to the performance of 3D hand pose estimation. We thereby introduce two new objective functions, Angle and Direction loss, to take the hand structure into account. While Angle loss covers locally kinematic information, Direction loss handles globally kinematic one. Our LG-Hand achieves promising results on the First-Person Hand Action Benchmark (FPHAB) dataset. We also perform an ablation study to show the efficacy of the two proposed objective functions.
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语义分割是开发医学图像诊断系统的重要任务。但是,构建注释的医疗数据集很昂贵。因此,在这种情况下,半监督方法很重要。在半监督学习中,标签的质量在模型性能中起着至关重要的作用。在这项工作中,我们提出了一种新的伪标签策略,可提高用于培训学生网络的伪标签的质量。我们遵循多阶段的半监督训练方法,该方法在标记的数据集上训练教师模型,然后使用训练有素的老师将伪标签渲染用于学生培训。通过这样做,伪标签将被更新,并且随着培训的进度更加精确。上一个和我们的方法之间的关键区别在于,我们在学生培训过程中更新教师模型。因此,在学生培训过程中,提高了伪标签的质量。我们还提出了一种简单但有效的策略,以使用动量模型来提高伪标签的质量 - 训练过程中原始模型的慢复制版本。通过应用动量模型与学生培训期间的重新渲染伪标签相结合,我们在五个数据集中平均达到了84.1%的骰子分数(即Kvarsir,CVC-ClinicdB,Etis-laribpolypdb,cvc-colondb,cvc-colondb,cvc-colondb和cvc-300)和CVC-300)只有20%的数据集用作标记数据。我们的结果超过了3%的共同实践,甚至在某些数据集中取得了完全监督的结果。我们的源代码和预培训模型可在https://github.com/sun-asterisk-research/online学习SSL上找到
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持久图(PDS)通常以同源性类别的死亡和出生为特征,以提供图形结构的拓扑表示,通常在机器学习任务中有用。先前的作品依靠单个图形签名来构建PD。在本文中,我们探讨了多尺度图标志家族的使用,以增强拓扑特征的鲁棒性。我们提出了一个深度学习体系结构来处理该集合的输入。基准图分类数据集上的实验表明,与使用图神经网络的最新方法相比,我们所提出的架构优于其他基于同源的方法,并实现其他基于同源的方法,并实现竞争性能。此外,我们的方法可以轻松地应用于大尺寸的输入图,因为它不会遭受有限的可伸缩性,这对于图内核方法可能是一个问题。
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