EAGER: CDS&E: Applied geometry and harmonic analysis in deep learning regularization: theory and applications

在这个大数据时代，深度学习已经成为一个新兴领域，具有推动科学、技术和人类生活的巨大潜力。尽管深度神经网络(DNN)在各种数据密集型机器学习应用中取得了巨大的实践成功，但仍有许多有待解决的问题：(1)当可用训练数据稀缺时，DNN往往存在过度拟合问题，这使得它们在小数据制度下的效率较低。(2)DNN被证明具有完美地“记忆”随机训练样本的能力，当训练数据受到噪声和破坏时，它们的可信度较低。(3)尽管对称性在机器学习中无处不在(例如，在图像分类中，如果图像被空间重新缩放和平移，则图像的类别标签保持不变)，但一般的DNN体系结构通常破坏表示中的这种对称性，这导致模型中的显著冗余，以从数据中记忆这样的信息。该项目的目标是通过利用数据及其网络表示中的低维几何和对称性来解决深度学习中的这些挑战，旨在开发深度学习正规化的新理论和方法，从而在机器学习和人工智能方面取得切实进展，特别是在小数据/受破坏的数据制度下。此外，该项目还为博士后提供了研究培训机会。该项目的总体主题是利用微分几何和应用调和分析在数学方法方面的最新进展来提高深度学习的稳定性、可靠性、数据效率和可解释性。这将包括发展基础理论和有效的算法来实现以下三个目标：(1)通过关注输入数据及其表示的拓扑和几何，开发具有显著改进的泛化性能的基于流形的DNN正则化。这将释放小数据制度中深度学习的潜力。(2)建立并分析了一种在深度学习中施加几何约束的创新框架，该框架具有极大的限制DNN记忆能力的潜力。对这种模型训练动态的数学分析将有助于理解深度学习中“记忆”和“泛化”之间的根本区别。(3)针对不同数据域上的各种对称变换，构造变形稳健的保对称DNN结构。通过将对称信息硬连接到变形稳健表示中，正则化的DNN模型将在减少冗余和模型规模的情况下提高性能和可解释性。在应用方面，该项目将在真实世界的机器学习任务中演示和部署所提出的理论，如对象识别、定位和分割。该项目开发的技术将广泛应用于不同学科，为下一代用于大数据计算建模的数学工具提供基础构建块。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

In this era of Big Data, deep learning has become a burgeoning domain with immense potential to advance science, technology, and human life. Despite the tremendous practical success of deep neural networks (DNNs) in various data-intensive machine learning applications, there remain many open problems to be addressed: (1) DNNs tend to suffer from overfitting when the available training data are scarce, which renders them less effective in the small data regime. (2) DNNs have been shown to have the capability of perfectly “memorizing” random training samples, making them less trustworthy when the training data are noisy and corrupted. (3) While symmetry is ubiquitous in machine learning (e.g., in image classification, the class label of an image remains the same if the image is spatially rescaled and translated,) generic DNN architectures typically destroy such symmetry in the representation, which leads to significant redundancy in the model to “memorize” such information from the data. The goal of this project is to address these challenges in deep learning by exploiting the low-dimensional geometry and symmetry within the data and their network representations, aiming at developing new theories and methodologies for deep learning regularization that can lead to tangible advances in machine learning and artificial intelligence, especially in the small/corrupted data regime. In addition, the project also provides research training opportunities for postdocs. The overarching theme of this project is to leverage recent progress in mathematical methods from differential geometry and applied harmonic analysis to improve the stability, reliability, data efficiency, and interpretability of deep learning. This will involve developing both foundational theories and efficient algorithms to achieve the following three objectives: (1) developing manifold-based DNN regularizations with significantly improved generalization performance by focusing on the topology and geometry of both the input data and their representations. This will unlock the potential of deep learning in the small data regime. (2) Establishing and analyzing an innovative framework of imposing geometric constraints in deep learning that has immense potential to limit the memorizing capacity of DNN. The mathematical analysis of the training dynamics of such a model will shed light on the understanding of the fundamental difference between “memorization” and generalization in deep learning. (3) The construction of deformation robust symmetry-preserving DNN architectures for various symmetry transformations on different data domains. By "hardwiring" the symmetry information into the deformation robust representations, the regularized DNN models will have improved performance and interpretability with reduced redundancy and model size. In terms of application, the project will demonstrate and deploy the proposed theories in real-world machine learning tasks, such as object recognition, localization, and segmentation. The techniques developed in this project will be widely applicable across different disciplines, providing fundamental building blocks for the next generation of mathematical tools for the computational modeling of Big Data.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.