The success of deep learning is partly attributed to the availability of massive data downloaded freely from the Internet. However, it also means that users' private data may be collected by commercial organizations without consent and used to train their models. Therefore, it's important and necessary to develop a method or tool to prevent unauthorized data exploitation. In this paper, we propose ConfounderGAN, a generative adversarial network (GAN) that can make personal image data unlearnable to protect the data privacy of its owners. Specifically, the noise produced by the generator for each image has the confounder property. It can build spurious correlations between images and labels, so that the model cannot learn the correct mapping from images to labels in this noise-added dataset. Meanwhile, the discriminator is used to ensure that the generated noise is small and imperceptible, thereby remaining the normal utility of the encrypted image for humans. The experiments are conducted in six image classification datasets, consisting of three natural object datasets and three medical datasets. The results demonstrate that our method not only outperforms state-of-the-art methods in standard settings, but can also be applied to fast encryption scenarios. Moreover, we show a series of transferability and stability experiments to further illustrate the effectiveness and superiority of our method.

Machine learning (ML) is revolutionizing protein structural analysis, including an important subproblem of predicting protein residue contact maps, i.e., which amino-acid residues are in close spatial proximity given the amino-acid sequence of a protein. Despite recent progresses in ML-based protein contact prediction, predicting contacts with a wide range of distances (commonly classified into short-, medium- and long-range contacts) remains a challenge. Here, we propose a multiscale graph neural network (GNN) based approach taking a cue from multiscale physics simulations, in which a standard pipeline involving a recurrent neural network (RNN) is augmented with three GNNs to refine predictive capability for short-, medium- and long-range residue contacts, respectively. Test results on the ProteinNet dataset show improved accuracy for contacts of all ranges using the proposed multiscale RNN+GNN approach over the conventional approach, including the most challenging case of long-range contact prediction.

Offline multi-agent reinforcement learning (MARL) aims to learn effective multi-agent policies from pre-collected datasets, which is an important step toward the deployment of multi-agent systems in real-world applications. However, in practice, each individual behavior policy that generates multi-agent joint trajectories usually has a different level of how well it performs. e.g., an agent is a random policy while other agents are medium policies. In the cooperative game with global reward, one agent learned by existing offline MARL often inherits this random policy, jeopardizing the performance of the entire team. In this paper, we investigate offline MARL with explicit consideration on the diversity of agent-wise trajectories and propose a novel framework called Shared Individual Trajectories (SIT) to address this problem. Specifically, an attention-based reward decomposition network assigns the credit to each agent through a differentiable key-value memory mechanism in an offline manner. These decomposed credits are then used to reconstruct the joint offline datasets into prioritized experience replay with individual trajectories, thereafter agents can share their good trajectories and conservatively train their policies with a graph attention network (GAT) based critic. We evaluate our method in both discrete control (i.e., StarCraft II and multi-agent particle environment) and continuous control (i.e, multi-agent mujoco). The results indicate that our method achieves significantly better results in complex and mixed offline multi-agent datasets, especially when the difference of data quality between individual trajectories is large.

在存在未衡量的混杂因素的情况下，我们解决了数据融合的治疗效应估计问题，即在不同的治疗分配机制下收集的多个数据集。例如，营销人员可以在不同时间/地点为相同产品分配不同的广告策略。为了处理由未衡量的混杂因素和数据融合引起的偏见，我们建议将观察数据分为多组（每个组具有独立治疗分配机制），然后将组指标显式地模拟为潜在的组仪器变量（LATGIV），将其模拟为实施基于IV的回归。在本文中，我们概念化了这种思想，并开发了一个统一的框架，以（1）估计跨群体观察到的变量的分布差异； （2）对不同治疗分配机制的LATGIV模型； （3）插入latgivs以估计治疗响应函数。经验结果证明了与最新方法相比，LATGIV的优势。

这是本文的第二部分，为异质变化检测（HCD）问题提供了新的策略，即从图形信号处理（GSP）的角度解决HCD。我们构造一个图表以表示每个图像的结构，并将每个图像视为图表上定义的图形信号。这样，我们可以将HCD问题转换为图表上定义的系统的信号响应的比较。在第一部分中，通过比较顶点域的图之间的结构差来衡量变化。在本第二部分中，我们分析了来自光谱域的HCD的GSP。我们首先分析同一图上不同图像的光谱特性，并表明它们的光谱表现出共同点和差异。特别是，正是变化导致了光谱的差异。然后，我们提出了HCD的回归模型，该模型将源信号分解为回归信号并更改信号，并且需要回归的信号具有与同一图上的目标信号相同的光谱属性。借助图光谱分析，提出的回归模型是灵活且可扩展的。对七个真实数据集进行的实验显示了该方法的有效性。

本文为异构变化检测（HCD）问题提供了一种新的策略：从图形信号处理（GSP）的角度解决HCD。我们为每个图像构造一个图表以捕获结构信息，并将每个图像视为图形信号。通过这种方式，我们将HCD转换为GSP问题：对两个图上定义的不同系统的响应的比较，试图找到结构性差异（第I部分）和信号差异（第II部分）异质图像之间的变化。在第一部分中，我们用顶点域的GSP分析了HCD。我们首先证明，对于未改变的图像，它们的结构是一致的，然后在两个图上定义的系统上的相同信号的输出相似。但是，一旦区域发生变化，图像的局部结构会发生变化，即包含该区域的顶点的连通性发生变化。然后，我们可以比较通过在两个图上定义的过滤器的相同输入图信号的输出信号以检测更改。我们设计了来自顶点域的不同过滤器，可以灵活地探索原始图中隐藏的高阶邻域信息。我们还从信号传播的角度分析了变化区域对变化检测结果的有害影响。在七个真实数据集上进行的实验显示了基于顶点域滤波的HCD方法的有效性。

宫颈异常细胞检测是一项具有挑战性的任务，因为异常细胞和正常细胞之间的形态差异通常是微妙的。为了确定宫颈细胞是正常还是异常，细胞病理学家总是将周围细胞作为参考，并进行仔细比较以鉴定其异常。为了模仿这些临床行为，我们建议探索上下文关系，以提高宫颈异常细胞检测的性能。具体而言，利用细胞和细胞到全球图像之间的上下文关系，以增强每个感兴趣区域（ROI）建议的特征。因此，开发了两个模块，称为ROI关系注意模块（RRAM）和全球ROI注意模块（GRAM），还研究了它们的组合策略。我们通过使用特征金字塔网络（FPN）使用单头或双头更快的R-CNN来设置强基础，并将我们的RRAM和革兰氏集整合到它们中以验证提出的模块的有效性。由40,000个细胞学图像组成的大宫颈细胞检测数据集进行的实验表明，RRAM和GRAM的引入都比基线方法获得了更好的平均精度（AP）。此外，当级联RRAM和GRAM时，我们的方法优于最先进的方法（SOTA）方法。此外，我们还显示了提出的功能增强方案可以促进图像级别和涂片级别的分类。代码和训练有素的模型可在https://github.com/cviu-csu/cr4cacd上公开获得。

协作多代理增强学习（MARL）已在许多实际应用中广泛使用，在许多实际应用中，每个代理商都根据自己的观察做出决定。大多数主流方法在对分散的局部实用程序函数进行建模时，将每个局部观察结果视为完整的。但是，他们忽略了这样一个事实，即可以将局部观察信息进一步分为几个实体，只有一部分实体有助于建模推理。此外，不同实体的重要性可能会随着时间而变化。为了提高分散政策的性能，使用注意机制用于捕获本地信息的特征。然而，现有的注意模型依赖于密集的完全连接的图，并且无法更好地感知重要状态。为此，我们提出了一个稀疏的状态MARL（S2RL）框架，该框架利用稀疏的注意机制将无关的信息丢弃在局部观察中。通过自我注意力和稀疏注意机制估算局部效用函数，然后将其合并为标准的关节价值函数和中央评论家的辅助关节价值函数。我们将S2RL框架设计为即插即用的模块，使其足够一般，可以应用于各种方法。关于Starcraft II的广泛实验表明，S2RL可以显着提高许多最新方法的性能。

虽然注释大量的数据以满足复杂的学习模型，但对于许多现实世界中的应用程序可能会过于良好。主动学习（AL）和半监督学习（SSL）是两个有效但经常被隔离的方法，可以减轻渴望数据的问题。最近的一些研究探索了将AL和SSL相结合以更好地探测未标记数据的潜力。但是，几乎所有这些当代的SSL-AL作品都采用了简单的组合策略，忽略了SSL和AL的固有关系。此外，在处理大规模，高维数据集时，其他方法则遭受高计算成本。通过标记数据的行业实践的激励，我们提出了一种基于创新的基于不一致的虚拟对抗性积极学习（理想）算法，以进一步研究SSL-AL的潜在优势，并实现Al和SSL的相互增强，即SSL，即SSL宣传标签信息，以使标签信息无标记的样本信息并为Al提供平滑的嵌入，而AL排除了具有不一致的预测和相当不确定性的样品。我们通过不同粒度的增强策略（包括细粒度的连续扰动探索和粗粒数据转换）来估计未标记的样品的不一致。在文本和图像域中，广泛的实验验证了所提出的算法的有效性，并将其与最先进的基线进行了比较。两项实际案例研究可视化应用和部署所提出的数据采样算法的实际工业价值。

Thompson sampling has proven effective across a wide range of stationary bandit environments. However, as we demonstrate in this paper, it can perform poorly when applied to nonstationary environments. We show that such failures are attributed to the fact that, when exploring, the algorithm does not differentiate actions based on how quickly the information acquired loses its usefulness due to nonstationarity. Building upon this insight, we propose predictive sampling, which extends Thompson sampling to do this. We establish a Bayesian regret bound and establish that, in nonstationary bandit environments, the regret incurred by Thompson sampling can far exceed that of predictive sampling. We also present implementations of predictive sampling that scale to complex bandit environments of practical interest in a computationally tractable manner. Through simulations, we demonstrate that predictive sampling outperforms Thompson sampling and other state-of-the-art algorithms across a wide range of nonstationary bandit environments.