We develop a corrective mechanism for neural network approximation: the total available non-linear units are divided into multiple groups and the first group approximates the function under consideration, the second group approximates the error in approximation produced by the first group and corrects it, the third group approximates the error produced by the first and second groups together and so on. This technique yields several new representation and learning results for neural networks. First, we show that two-layer neural networks in the random features regime (RF) can memorize arbitrary labels for arbitrary points under under Euclidean distance separation condition using $\tilde{O}(n)$ ReLUs which is optimal in $n$ up to logarithmic factors. Next, we give a powerful representation result for two-layer neural networks with ReLUs and smoothed ReLUs which can achieve a squared error of at most $ε$ with $O(C(a,d)ε^{-1/(a+1)})$ for $a \in \mathbb{N}\cup\{0\}$ when the function is smooth enough (roughly when it has $Θ(ad)$ bounded derivatives). In certain cases $d$ can be replaced with effective dimension $q \ll d$. Previous results of this type implement Taylor series approximation using deep architectures. We also consider three-layer neural networks and show that the corrective mechanism yields faster representation rates for smooth radial functions. Lastly, we obtain the first $O(\mathrm{subpoly}(1/ε))$ upper bound on the number of neurons required for a two layer network to learn low degree polynomials up to squared error $ε$ via gradient descent. Even though deep networks can express these polynomials with $O(\mathrm{polylog}(1/ε))$ neurons, the best learning bounds on this problem require $\mathrm{poly}(1/ε)$ neurons.
Adynamical systems view of training generativemodels and the memorization phenomenon
International Institute for Theoretical Sciences（理论科学国际研究所）；Department of Computer Science and Automation（计算机科学与自动化系）；Indian Institute of Science（印度科学研究所）；Department of Electrical Engineering（电气工程系）；Indian Institute of Technology Bombay（博亚理工大学）
Expert demonstrations are a rich source of supervision for training visual robotic manipulation policies, but imitation learning methods often require either a large number of demonstrations or expensive online expert supervision to learn reactive closed-loop behaviors. In this work, we introduce SPARTN (Synthetic Perturbations for Augmenting Robot Trajectories via NeRF): a fully-offline data augmentation scheme for improving robot policies that use eye-in-hand cameras. Our approach leverages neural radiance fields (NeRFs) to synthetically inject corrective noise into visual demonstrations, us…
Pairwise AUC Optimization Needs Corrective Power: A Unified View
School of Computer Science and Technology, University of Chinese Academy of Sciences（中国科学院大学计算机科学与技术学院）；Institute of Computing Technology, Chinese Academy of Sciences（中国科学院计算技术研究所）
University of Pisa（比萨大学）；University of Padova（帕多瓦大学）
Learning to solve sequential tasks with recurrent models requires the ability to memorize long sequences and to extract task-relevant features from them. In this paper, we study the memorization subtask from the point of view of the design and training of recurrent neural networks. We propose a new model, the Linear Memory Network, which features an encoding-based memorization component built with a linear autoencoder for sequences. We extend the memorization component with a modular memory that encodes the hidden state sequence at different sampling frequencies. Additionally, we provide a spe…
Flatness is Necessary, Neural Collapse is Not: Rethinking Generalization via Grokking
Ting Han Lamarr Institute, TU Dortmund, Germany（廷汉拉马尔研究所，杜伊斯堡-艾森大学，德国）；Institute for AI in Medicine, UK Essen（人工智能医学研究所，英国埃森）；Research Center Trustworthy Data Science and Security of the University Alliance Ruhr, TU Dortmund, Germany（trustworthy数据科学与安全研究所以及鲁尔大学联盟，杜伊斯堡-艾森大学，德国）；Ruhr University Bochum, Germany（波恩鲁尔大学，德国）；Department of Physics, TU Dortmund, Germany（物理系，杜伊斯堡-艾森大学，德国）；Lamarr Institute, TU Dortmund, Germany（廷汉拉马尔研究所，杜伊斯堡-艾森大学，德国）
University of Queensland（昆士兰大学）；Mila, University of Montreal（蒙特利尔大学Mila）；Huawei Noah’s Ark Lab（华为诺亚方舟实验室）；University of Toronto（多伦多大学）；Samsung AI Research Center, Toronto（多伦多三星人工智能研究中心）
The impressive performance of deep convolutional neural networks in single-view 3D reconstruction suggests that these models perform non-trivial reasoning about the 3D structure of the output space. However, recent work has challenged this belief, showing that complex encoder-decoder architectures perform similarly to nearest-neighbor baselines or simple linear decoder models that exploit large amounts of per category data in standard benchmarks. On the other hand settings where 3D shape must be inferred for new categories with few examples are more natural and require models that generalize a…
Utrecht University（乌得勒支大学）；Université Catholique de Louvain（鲁汶大学）
Neural networks with random weights appear in a variety of machine learning applications, most prominently as the initialization of many deep learning algorithms and as a computationally cheap alternative to fully learned neural networks. In the present article, we enhance the theoretical understanding of random neural networks by addressing the following data separation problem: under what conditions can a random neural network make two classes $\mathcal{X}^-, \mathcal{X}^+ \subset \mathbb{R}^d$ (with positive distance) linearly separable? We show that a sufficiently large two-layer ReLU-netw…
Neural networks are very successful tools in for example advanced classification. From a statistical point of view, fitting a neural network may be seen as a kind of regression, where we seek a function from the input space to a space of classification probabilities that follows the "general" shape of the data, but avoids overfitting by avoiding memorization of individual data points. In statistics, this can be done by controlling the geometric complexity of the regression function. We propose to do something similar when fitting neural networks by controlling the slope of the network. After d…
Zhejiang University（浙江大学）；Alibaba Group（阿里巴巴集团）；Baidu Research（百度研究院）；University of Notre Dame（圣母大学）
Graph Neural Networks (GNNs) have become widely-used models for semi-supervised learning. However, the robustness of GNNs in the presence of label noise remains a largely under-explored problem. In this paper, we consider an important yet challenging scenario where labels on nodes of graphs are not only noisy but also scarce. In this scenario, the performance of GNNs is prone to degrade due to label noise propagation and insufficient learning. To address these issues, we propose a novel RTGNN (Robust Training of Graph Neural Networks via Noise Governance) framework that achieves better robustn…
