Graph neural networks (GNNs) have been demonstrated to be a powerful algorithmic model in broad application fields for their effectiveness in learning over graphs. To scale GNN training up for large-scale and ever-growing graphs, the most promising solution is distributed training which distributes the workload of training across multiple computing nodes. However, the workflows, computational patterns, communication patterns, and optimization techniques of distributed GNN training remain preliminarily understood. In this paper, we provide a comprehensive survey of distributed GNN training by investigating various optimization techniques used in distributed GNN training. First, distributed GNN training is classified into several categories according to their workflows. In addition, their computational patterns and communication patterns, as well as the optimization techniques proposed by recent work are introduced. Second, the software frameworks and hardware platforms of distributed GNN training are also introduced for a deeper understanding. Third, distributed GNN training is compared with distributed training of deep neural networks, emphasizing the uniqueness of distributed GNN training. Finally, interesting issues and opportunities in this field are discussed.

大规模图在现实情况下无处不在，可以通过图神经网络（GNN）训练以生成下游任务的表示形式。鉴于大规模图的丰富信息和复杂的拓扑结构，我们认为在这样的图中存在冗余，并将降低训练效率。不幸的是，模型可伸缩性严重限制了通过香草GNNS训练大规模图的效率。尽管在基于抽样的培训方法方面取得了最新进展，但基于抽样的GNN通常忽略了冗余问题。在大规模图上训练这些型号仍然需要无法容忍的时间。因此，我们建议通过重新思考图中的固有特征来降低冗余并提高使用GNN的大规模训练效率。在本文中，我们开拓者提出了一种称为dropreef的曾经使用的方法，以在大规模图中删除冗余。具体而言，我们首先进行初步实验，以探索大规模图中的潜在冗余。接下来，我们提出一个度量标准，以量化图中所有节点的异质性。基于实验和理论分析，我们揭示了大规模图中的冗余，即具有高邻居异质的节点和大量邻居。然后，我们建议Dropreef一劳永逸地检测并删除大规模图中的冗余，以帮助减少训练时间，同时确保模型准确性没有牺牲。为了证明DropReef的有效性，我们将其应用于最新的基于最新的采样GNN，用于训练大规模图，这是由于此类模型的高精度。使用Dropreef杠杆，可以大力提高模型的训练效率。 Dropreef高度兼容，并且在离线上执行，从而在很大程度上使目前和未来的最新采样GNN受益。

异质图神经网络（HGNN）提供了强大的能力，可以将异质图的丰富结构和语义信息嵌入到低维节点表示中。现有的HGNN通常会学习使用层次结构注意机制和重复的邻居聚集来嵌入信息，并遭受不必要的复杂性和冗余计算。本文提出了简单有效的异质图神经网络（SEHGNN），该图通过避免在相同关系中避免过度使用的节点级别的注意来降低这种过度的复杂性，并在预处理阶段预先计算邻居聚集。与以前的工作不同，Sehgnn利用轻重量参数的邻居聚合器来学习每个Metapath的结构信息，以及一个基于变压器的语义聚合器将跨Metapaths的语义信息组合为每个节点的最终嵌入。结果，SEHGNN提供了简单的网络结构，高预测准确性和快速训练速度。在五个现实世界的异质图上进行了广泛的实验，证明了Sehgnn在准确性和训练速度上的优越性。代码可在https://github.com/ict-gimlab/sehgnn上找到。

采样是图形神经网络（GNN）培训的关键操作，有助于降低成本。以前的文献已经通过数学和统计方法探索了改进采样算法。但是，采样算法和硬件之间存在差距。在不考虑硬件的情况下，算法设计人员仅在算法级别优化采样，缺少通过利用硬件功能来促进现有采样算法效率的巨大潜力。在本文中，我们开创了一个为主流采样算法提出的统一编程模型，称为GNNSampler，涵盖了各个类别中采样算法的关键过程。其次，为了利用硬件功能，我们选择数据局部性作为案例研究，并在图中探索节点及其邻居之间的数据位置，以减轻采样中不规则的内存访问。第三，我们在GNNSampler中实现了各种采样算法的局部感知优化，以优化一般的采样过程。最后，我们强调在大图数据集上进行实验，以分析训练时间，准确性和硬件级指标之间的相关性。广泛的实验表明，我们的方法通用到主流采样算法，并有助于大大减少训练时间，尤其是在大规模图中。

Accurate determination of a small molecule candidate (ligand) binding pose in its target protein pocket is important for computer-aided drug discovery. Typical rigid-body docking methods ignore the pocket flexibility of protein, while the more accurate pose generation using molecular dynamics is hindered by slow protein dynamics. We develop a tiered tensor transform (3T) algorithm to rapidly generate diverse protein-ligand complex conformations for both pose and affinity estimation in drug screening, requiring neither machine learning training nor lengthy dynamics computation, while maintaining both coarse-grain-like coordinated protein dynamics and atomistic-level details of the complex pocket. The 3T conformation structures we generate are closer to experimental co-crystal structures than those generated by docking software, and more importantly achieve significantly higher accuracy in active ligand classification than traditional ensemble docking using hundreds of experimental protein conformations. 3T structure transformation is decoupled from the system physics, making future usage in other computational scientific domains possible.

For Prognostics and Health Management (PHM) of Lithium-ion (Li-ion) batteries, many models have been established to characterize their degradation process. The existing empirical or physical models can reveal important information regarding the degradation dynamics. However, there is no general and flexible methods to fuse the information represented by those models. Physics-Informed Neural Network (PINN) is an efficient tool to fuse empirical or physical dynamic models with data-driven models. To take full advantage of various information sources, we propose a model fusion scheme based on PINN. It is implemented by developing a semi-empirical semi-physical Partial Differential Equation (PDE) to model the degradation dynamics of Li-ion-batteries. When there is little prior knowledge about the dynamics, we leverage the data-driven Deep Hidden Physics Model (DeepHPM) to discover the underlying governing dynamic models. The uncovered dynamics information is then fused with that mined by the surrogate neural network in the PINN framework. Moreover, an uncertainty-based adaptive weighting method is employed to balance the multiple learning tasks when training the PINN. The proposed methods are verified on a public dataset of Li-ion Phosphate (LFP)/graphite batteries.

Non-line-of-sight (NLOS) imaging aims to reconstruct the three-dimensional hidden scenes from the data measured in the line-of-sight, which uses photon time-of-flight information encoded in light after multiple diffuse reflections. The under-sampled scanning data can facilitate fast imaging. However, the resulting reconstruction problem becomes a serious ill-posed inverse problem, the solution of which is of high possibility to be degraded due to noises and distortions. In this paper, we propose two novel NLOS reconstruction models based on curvature regularization, i.e., the object-domain curvature regularization model and the dual (i.e., signal and object)-domain curvature regularization model. Fast numerical optimization algorithms are developed relying on the alternating direction method of multipliers (ADMM) with the backtracking stepsize rule, which are further accelerated by GPU implementation. We evaluate the proposed algorithms on both synthetic and real datasets, which achieve state-of-the-art performance, especially in the compressed sensing setting. All our codes and data are available at https://github.com/Duanlab123/CurvNLOS.

Masked image modeling (MIM) has shown great promise for self-supervised learning (SSL) yet been criticized for learning inefficiency. We believe the insufficient utilization of training signals should be responsible. To alleviate this issue, we introduce a conceptually simple yet learning-efficient MIM training scheme, termed Disjoint Masking with Joint Distillation (DMJD). For disjoint masking (DM), we sequentially sample multiple masked views per image in a mini-batch with the disjoint regulation to raise the usage of tokens for reconstruction in each image while keeping the masking rate of each view. For joint distillation (JD), we adopt a dual branch architecture to respectively predict invisible (masked) and visible (unmasked) tokens with superior learning targets. Rooting in orthogonal perspectives for training efficiency improvement, DM and JD cooperatively accelerate the training convergence yet not sacrificing the model generalization ability. Concretely, DM can train ViT with half of the effective training epochs (3.7 times less time-consuming) to report competitive performance. With JD, our DMJD clearly improves the linear probing classification accuracy over ConvMAE by 5.8%. On fine-grained downstream tasks like semantic segmentation, object detection, etc., our DMJD also presents superior generalization compared with state-of-the-art SSL methods. The code and model will be made public at https://github.com/mx-mark/DMJD.

Reinforcement learning (RL) is one of the most important branches of AI. Due to its capacity for self-adaption and decision-making in dynamic environments, reinforcement learning has been widely applied in multiple areas, such as healthcare, data markets, autonomous driving, and robotics. However, some of these applications and systems have been shown to be vulnerable to security or privacy attacks, resulting in unreliable or unstable services. A large number of studies have focused on these security and privacy problems in reinforcement learning. However, few surveys have provided a systematic review and comparison of existing problems and state-of-the-art solutions to keep up with the pace of emerging threats. Accordingly, we herein present such a comprehensive review to explain and summarize the challenges associated with security and privacy in reinforcement learning from a new perspective, namely that of the Markov Decision Process (MDP). In this survey, we first introduce the key concepts related to this area. Next, we cover the security and privacy issues linked to the state, action, environment, and reward function of the MDP process, respectively. We further highlight the special characteristics of security and privacy methodologies related to reinforcement learning. Finally, we discuss the possible future research directions within this area.

Detecting abrupt changes in data distribution is one of the most significant tasks in streaming data analysis. Although many unsupervised Change-Point Detection (CPD) methods have been proposed recently to identify those changes, they still suffer from missing subtle changes, poor scalability, or/and sensitive to noise points. To meet these challenges, we are the first to generalise the CPD problem as a special case of the Change-Interval Detection (CID) problem. Then we propose a CID method, named iCID, based on a recent Isolation Distributional Kernel (IDK). iCID identifies the change interval if there is a high dissimilarity score between two non-homogeneous temporal adjacent intervals. The data-dependent property and finite feature map of IDK enabled iCID to efficiently identify various types of change points in data streams with the tolerance of noise points. Moreover, the proposed online and offline versions of iCID have the ability to optimise key parameter settings. The effectiveness and efficiency of iCID have been systematically verified on both synthetic and real-world datasets.