尽管已经取得了重大的理论进步,但揭示了过度参数化神经网络的概括之谜仍然难以捉摸。在本文中,我们通过利用算法稳定性的概念来研究浅神经网络(SNN)的概括行为。我们考虑梯度下降(GD)和随机梯度下降(SGD)来训练SNN,因为这两者都通过通过早期停止来平衡优化和概括来发展一致的多余风险范围。与现有的GD分析相比,我们的新分析需要放松的过度参数化假设,并且还适用于SGD。改进的关键是更好地估计经验风险的Hessian矩阵的最小特征值,以及通过提供对其迭代材料的精制估计,沿GD和SGD的轨迹沿GD和SGD的轨迹进行了更好的估计。
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最近,有大量的工作致力于研究马尔可夫链随机梯度方法(MC-SGMS),这些方法主要集中于他们解决最小化问题的收敛分析。在本文中,我们通过统计学习理论框架中的算法稳定性镜头对MC-SGM进行了全面的MC-SGMS分析。对于经验风险最小化(ERM)问题,我们通过引入实用的论点稳定性来建立平稳和非平滑案例的最佳人口风险界限。对于最小值问题,我们建立了在平均参数稳定性和概括误差之间的定量连接,该误差扩展了均匀稳定性\ cite {lei2021Staritibal}的现有结果。我们进一步开发了预期和高概率的凸孔问题问题的第一个几乎最佳的收敛速率,这与我们的稳定性结果相结合,表明可以在平滑和非平滑案例中达到最佳的概括界限。据我们所知,这是对梯度从马尔可夫过程采样时对SGM的首次概括分析。
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在本文中,通过引入低噪声条件,我们研究了在随机凸出优化(SCO)的环境中,差异私有随机梯度下降(SGD)算法的隐私和效用(概括)表现。对于点心学习,我们建立了订单$ \ Mathcal {o} \ big(\ frac {\ sqrt {\ sqrt {d \ log(1/\ delta)}} {n \ epsilon} \ big)和$ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \\ \ \ \ \\ \ \ \ \ \ big(\ frac {\ frac {\ sqrt {\ sqrt {\ sqrt {\ sqrt {\ sqrt {\ sqrt {\ sqrt {\ sqrt {\ sqrt { Mathcal {o} \ big({n^{ - \ frac {1+ \ alpha} {2}}}}}}+\ frac {\ sqrt {d \ log(1/\ delta)}}} )$(\ epsilon,\ delta)$ - 差异化私有SGD算法,分别是较高的和$ \ alpha $ -h \'分别较旧的光滑损失,其中$ n $是样本尺寸,$ d $是维度。对于成对学习,受\ cite {lei2020sharper,lei2021Generalization}的启发,我们提出了一种基于梯度扰动的简单私人SGD算法,该算法满足$(\ epsilon,\ delta)$ - 差异性限制,并开发出了新颖的私密性,并且算法。特别是,我们证明我们的算法可以实现多余的风险利率$ \ MATHCAL {o} \ big(\ frac {1} {\ sqrt {n}}}+\ frac {\ frac {\ sqrt { delta)}}} {n \ epsilon} \ big)$带有梯度复杂性$ \ mathcal {o}(n)$和$ \ mathcal {o} \ big(n^{\ frac {\ frac {2- \ alpha} {1+ alpha} {1+ \ alpha}}}+n \ big)$,用于强烈平滑和$ \ alpha $ -h \'olde R平滑损失。此外,在低噪声环境中建立了更快的学习率,以实现平滑和非平滑损失。据我们所知,这是第一次实用分析,它提供了超过$ \ Mathcal {o} \ big(\ frac {1} {\ sqrt {\ sqrt {n}}+\ frac {\ sqrt {d sqrt {d \ sqrt {d \ sqrt { log(1/\ delta)}}} {n \ epsilon} \ big)$用于隐私提供成对学习。
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随机梯度下降(SGDA)及其变体一直是解决最小值问题的主力。但是,与研究有差异隐私(DP)约束的经过良好研究的随机梯度下降(SGD)相反,在理解具有DP约束的SGDA的概括(实用程序)方面几乎没有工作。在本文中,我们使用算法稳定性方法在不同的设置中建立DP-SGDA的概括(实用程序)。特别是,对于凸 - 凸环设置,我们证明DP-SGDA可以在平滑和非平滑案例中都可以根据弱原始二元人群风险获得最佳的效用率。据我们所知,这是在非平滑案例中DP-SGDA的第一个已知结果。我们进一步在非convex-rong-concave环境中提供了实用性分析,这是原始人口风险的首个已知结果。即使在非私有设置中,此非convex设置的收敛和概括结果也是新的。最后,进行了数值实验,以证明DP-SGDA在凸和非凸病例中的有效性。
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大多数传统人群计数方法利用完全监督的学习框架来学习场景图像和人群密度映射之间的映射。在这种完全监督培训设置的情况下,需要大量昂贵且耗时的像素级注释,以产生密度图作为监控。减少昂贵标签的一种方法是利用未标记图像之间的自我结构信息和内在关系。与利用原始图像级别的这些关系和结构信息的先前方法不同,我们从潜在特征空间探讨了这种自我关系,因为它可以提取更丰富的关系和结构信息。具体而言,我们提出了S $ ^ 2 $ FPR,其可以提取结构信息,并在潜在空间中学习粗良好的金字塔特征的部分订单,以便更好地与大规模未标记的图像计数。此外,我们收集了一个新的未标记的人群计数数据集(Fudan-UCC),总共有4,000张图片进行培训。一个副产物是我们提出的S $ ^ 2 $ FPR方法可以利用未标记图像之间的潜在空间中的众多部分订单来加强模型表示能力,并减少人群计数任务的估计误差。关于四个基准数据集的大量实验,即UCF-QNRF,Shanghaitech Parta和Partb以及UCF-CC-50,与先前半监督方法相比,我们的方法显示了我们的方法。源代码和数据集可用于https://github.com/bridgeqiqi/s2fpr。
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成对学习是指损失函数取决于一对情况的学习任务。它实例化了许多重要的机器学习任务,如双级排名和度量学习。一种流行的方法来处理成对学习中的流数据是在线梯度下降(OGD)算法,其中需要将当前实例配对以前具有足够大的尺寸的先前实例的电流实例,因此遭受可扩展性问题。在本文中,我们提出了用于成对学习的简单随机和在线梯度下降方法。与现有研究的显着差异是,我们仅将当前实例与前一个构建梯度方向配对,这在存储和计算复杂性中是有效的。我们为凸和非凸起的展示结果,优化和泛化误差界以及平滑和非光滑问题都开发了新颖的稳定性结果,优化和泛化误差界限。我们引入了新颖的技术来解耦模型的依赖性和前一个例子在优化和泛化分析中。我们的研究解决了使用具有非常小的固定尺寸的缓冲集开发OGD的有意义的泛化范围的开放问题。我们还扩展了我们的算法和稳定性分析,以便为成对学习开发差异私有的SGD算法,这显着提高了现有结果。
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Face Anti-spoofing (FAS) is essential to secure face recognition systems from various physical attacks. However, recent research generally focuses on short-distance applications (i.e., phone unlocking) while lacking consideration of long-distance scenes (i.e., surveillance security checks). In order to promote relevant research and fill this gap in the community, we collect a large-scale Surveillance High-Fidelity Mask (SuHiFiMask) dataset captured under 40 surveillance scenes, which has 101 subjects from different age groups with 232 3D attacks (high-fidelity masks), 200 2D attacks (posters, portraits, and screens), and 2 adversarial attacks. In this scene, low image resolution and noise interference are new challenges faced in surveillance FAS. Together with the SuHiFiMask dataset, we propose a Contrastive Quality-Invariance Learning (CQIL) network to alleviate the performance degradation caused by image quality from three aspects: (1) An Image Quality Variable module (IQV) is introduced to recover image information associated with discrimination by combining the super-resolution network. (2) Using generated sample pairs to simulate quality variance distributions to help contrastive learning strategies obtain robust feature representation under quality variation. (3) A Separate Quality Network (SQN) is designed to learn discriminative features independent of image quality. Finally, a large number of experiments verify the quality of the SuHiFiMask dataset and the superiority of the proposed CQIL.
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Real-world robotic grasping can be done robustly if a complete 3D Point Cloud Data (PCD) of an object is available. However, in practice, PCDs are often incomplete when objects are viewed from few and sparse viewpoints before the grasping action, leading to the generation of wrong or inaccurate grasp poses. We propose a novel grasping strategy, named 3DSGrasp, that predicts the missing geometry from the partial PCD to produce reliable grasp poses. Our proposed PCD completion network is a Transformer-based encoder-decoder network with an Offset-Attention layer. Our network is inherently invariant to the object pose and point's permutation, which generates PCDs that are geometrically consistent and completed properly. Experiments on a wide range of partial PCD show that 3DSGrasp outperforms the best state-of-the-art method on PCD completion tasks and largely improves the grasping success rate in real-world scenarios. The code and dataset will be made available upon acceptance.
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Embedding words in vector space is a fundamental first step in state-of-the-art natural language processing (NLP). Typical NLP solutions employ pre-defined vector representations to improve generalization by co-locating similar words in vector space. For instance, Word2Vec is a self-supervised predictive model that captures the context of words using a neural network. Similarly, GLoVe is a popular unsupervised model incorporating corpus-wide word co-occurrence statistics. Such word embedding has significantly boosted important NLP tasks, including sentiment analysis, document classification, and machine translation. However, the embeddings are dense floating-point vectors, making them expensive to compute and difficult to interpret. In this paper, we instead propose to represent the semantics of words with a few defining words that are related using propositional logic. To produce such logical embeddings, we introduce a Tsetlin Machine-based autoencoder that learns logical clauses self-supervised. The clauses consist of contextual words like "black," "cup," and "hot" to define other words like "coffee," thus being human-understandable. We evaluate our embedding approach on several intrinsic and extrinsic benchmarks, outperforming GLoVe on six classification tasks. Furthermore, we investigate the interpretability of our embedding using the logical representations acquired during training. We also visualize word clusters in vector space, demonstrating how our logical embedding co-locate similar words.
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The surrogate loss of variational autoencoders (VAEs) poses various challenges to their training, inducing the imbalance between task fitting and representation inference. To avert this, the existing strategies for VAEs focus on adjusting the tradeoff by introducing hyperparameters, deriving a tighter bound under some mild assumptions, or decomposing the loss components per certain neural settings. VAEs still suffer from uncertain tradeoff learning.We propose a novel evolutionary variational autoencoder (eVAE) building on the variational information bottleneck (VIB) theory and integrative evolutionary neural learning. eVAE integrates a variational genetic algorithm into VAE with variational evolutionary operators including variational mutation, crossover, and evolution. Its inner-outer-joint training mechanism synergistically and dynamically generates and updates the uncertain tradeoff learning in the evidence lower bound (ELBO) without additional constraints. Apart from learning a lossy compression and representation of data under the VIB assumption, eVAE presents an evolutionary paradigm to tune critical factors of VAEs and deep neural networks and addresses the premature convergence and random search problem by integrating evolutionary optimization into deep learning. Experiments show that eVAE addresses the KL-vanishing problem for text generation with low reconstruction loss, generates all disentangled factors with sharp images, and improves the image generation quality,respectively. eVAE achieves better reconstruction loss, disentanglement, and generation-inference balance than its competitors.
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