It is crucial to choose the appropriate scale in order to build an effective and informational representation of a complex system. Scientists carefully choose the scales for their experiments to extract the variables that describe the causalities in the system. They found that the coarse scale(macro) is sometimes more causal and informative than the numerous-parameter observations(micro). The phenomenon that the causality emerges by coarse-graining is called Causal Emergence(CE). Based on information theory, a number of recent works quantitatively showed that CE indeed happens while coarse-graining a micro model to the macro. However, the existing works have not discussed the question of why and when the CE happens. We quantitatively analyze the redistribution of uncertainties for coarse-graining and suggest that the redistribution of uncertainties is the cause of causal emergence. We further analyze the thresholds that determine if CE happens or not. From the regularity of the transition probability matrix(TPM) of discrete systems, the mathematical expressions of the model properties are derived. The values of thresholds for different operations are computed. The results provide the critical and specific conditions of CE as helpful suggestions for choosing the proper coarse-graining operation. The results also provided a new way to better understand the nature of causality and causal emergence.

主观认知下降（SCD）是阿尔茨海默氏病（AD）的临床前阶段，甚至在轻度认知障碍（MCI）之前就发生。渐进式SCD将转换为MCI，并有可能进一步发展为AD。因此，通过神经成像技术（例如，结构MRI）对进行性SCD的早期鉴定对于AD的早期干预具有巨大的临床价值。但是，现有的基于MRI的机器/深度学习方法通​​常会遇到小样本大小的问题，这对相关的神经影像学分析构成了巨大挑战。我们旨在解决本文的主要问题是如何利用相关领域（例如AD/NC）协助SCD的进展预测。同时，我们担心哪些大脑区域与进行性SCD的识别更加紧密相关。为此，我们提出了一个注意引导自动编码器模型，以进行有效的跨域适应，以促进知识转移从AD到SCD。所提出的模型由四个关键组成部分组成：1）用于学习不同域的共享子空间表示的功能编码模块，2）用于自动定义大脑中定义的兴趣障碍区域的注意模块，3）用于重构的解码模块原始输入，4）用于鉴定脑疾病的分类模块。通过对这四个模块的联合培训，可以学习域不变功能。同时，注意机制可以强调与脑部疾病相关的区域。公开可用的ADNI数据集和私人CLAS数据集的广泛实验证明了该方法的有效性。提出的模型直接可以在CPU上仅5-10秒进行训练和测试，并且适用于具有小数据集的医疗任务。

变压器模型已经取得了有希望的自然语言处理（NLP）任务，包括提取问题应答（QA）。 NLP任务中使用的通用变压器编码器在所有层中处理上下文段落中所有输入令牌的隐藏状态。但是，与序列分类等其他任务不同，应答所提出的问题不一定需要上下文段落中的所有令牌。在此动机之后，我们提出了薄块撇子，这将在更高的隐藏层中略微浏览不必要的上下文，以改善和加速变压器性能。块撇屏的关键概念是识别必须进一步处理的上下文，并且可以在推理期间早期安全地丢弃的语言。批判性地，我们发现这些信息可以充分地从变压器模型内的自我注意重量得出。我们进一步将对应于下层的不必要位置对应的隐藏状态，实现了显着的推理时间加速。令我们惊讶的是，我们观察到这种方式修剪的模型优于他们的全尺寸对应物。 Block-Skim在不同数据集上提高了QA模型的准确性，并在BERT-Base模型上实现了3次加速。

基于混合的点云增强是一种流行的大规模公共数据集可用性问题的问题。但混合点和相应的语义标签之间的不匹配会阻碍诸如部分分割的方向任务中的进一步应用。本文提出了一种点云增强方法，Pointmanifoldcut（PMC），它取代了神经网络嵌入点，而不是欧几里德空间坐标。这种方法利用了在较高级别的神经网络的点已经培训，以培训以嵌入其邻居关系并混合这些表示不会混合自身与其标签之间的关系。我们在PointManifoldCut操作后设置了空间变换模块，以对齐嵌入式空间中的新实例。本文还讨论了不同隐藏层的效果和更换点的方法。实验表明，我们的建议方法可以增强点云分类以及分段网络的性能，并为攻击和几何变换带来了额外的鲁棒性。本文的代码可用于：https://github.com/fun0515/pinityManifoldcut。

Few Shot Instance Segmentation (FSIS) requires models to detect and segment novel classes with limited several support examples. In this work, we explore a simple yet unified solution for FSIS as well as its incremental variants, and introduce a new framework named Reference Twice (RefT) to fully explore the relationship between support/query features based on a Transformer-like framework. Our key insights are two folds: Firstly, with the aid of support masks, we can generate dynamic class centers more appropriately to re-weight query features. Secondly, we find that support object queries have already encoded key factors after base training. In this way, the query features can be enhanced twice from two aspects, i.e., feature-level and instance-level. In particular, we firstly design a mask-based dynamic weighting module to enhance support features and then propose to link object queries for better calibration via cross-attention. After the above steps, the novel classes can be improved significantly over our strong baseline. Additionally, our new framework can be easily extended to incremental FSIS with minor modification. When benchmarking results on the COCO dataset for FSIS, gFSIS, and iFSIS settings, our method achieves a competitive performance compared to existing approaches across different shots, e.g., we boost nAP by noticeable +8.2/+9.4 over the current state-of-the-art FSIS method for 10/30-shot. We further demonstrate the superiority of our approach on Few Shot Object Detection. Code and model will be available.

Benefiting from the intrinsic supervision information exploitation capability, contrastive learning has achieved promising performance in the field of deep graph clustering recently. However, we observe that two drawbacks of the positive and negative sample construction mechanisms limit the performance of existing algorithms from further improvement. 1) The quality of positive samples heavily depends on the carefully designed data augmentations, while inappropriate data augmentations would easily lead to the semantic drift and indiscriminative positive samples. 2) The constructed negative samples are not reliable for ignoring important clustering information. To solve these problems, we propose a Cluster-guided Contrastive deep Graph Clustering network (CCGC) by mining the intrinsic supervision information in the high-confidence clustering results. Specifically, instead of conducting complex node or edge perturbation, we construct two views of the graph by designing special Siamese encoders whose weights are not shared between the sibling sub-networks. Then, guided by the high-confidence clustering information, we carefully select and construct the positive samples from the same high-confidence cluster in two views. Moreover, to construct semantic meaningful negative sample pairs, we regard the centers of different high-confidence clusters as negative samples, thus improving the discriminative capability and reliability of the constructed sample pairs. Lastly, we design an objective function to pull close the samples from the same cluster while pushing away those from other clusters by maximizing and minimizing the cross-view cosine similarity between positive and negative samples. Extensive experimental results on six datasets demonstrate the effectiveness of CCGC compared with the existing state-of-the-art algorithms.

In robust Markov decision processes (MDPs), the uncertainty in the transition kernel is addressed by finding a policy that optimizes the worst-case performance over an uncertainty set of MDPs. While much of the literature has focused on discounted MDPs, robust average-reward MDPs remain largely unexplored. In this paper, we focus on robust average-reward MDPs, where the goal is to find a policy that optimizes the worst-case average reward over an uncertainty set. We first take an approach that approximates average-reward MDPs using discounted MDPs. We prove that the robust discounted value function converges to the robust average-reward as the discount factor $\gamma$ goes to $1$, and moreover, when $\gamma$ is large, any optimal policy of the robust discounted MDP is also an optimal policy of the robust average-reward. We further design a robust dynamic programming approach, and theoretically characterize its convergence to the optimum. Then, we investigate robust average-reward MDPs directly without using discounted MDPs as an intermediate step. We derive the robust Bellman equation for robust average-reward MDPs, prove that the optimal policy can be derived from its solution, and further design a robust relative value iteration algorithm that provably finds its solution, or equivalently, the optimal robust policy.

Representing and synthesizing novel views in real-world dynamic scenes from casual monocular videos is a long-standing problem. Existing solutions typically approach dynamic scenes by applying geometry techniques or utilizing temporal information between several adjacent frames without considering the underlying background distribution in the entire scene or the transmittance over the ray dimension, limiting their performance on static and occlusion areas. Our approach $\textbf{D}$istribution-$\textbf{D}$riven neural radiance fields offers high-quality view synthesis and a 3D solution to $\textbf{D}$etach the background from the entire $\textbf{D}$ynamic scene, which is called $\text{D}^4$NeRF. Specifically, it employs a neural representation to capture the scene distribution in the static background and a 6D-input NeRF to represent dynamic objects, respectively. Each ray sample is given an additional occlusion weight to indicate the transmittance lying in the static and dynamic components. We evaluate $\text{D}^4$NeRF on public dynamic scenes and our urban driving scenes acquired from an autonomous-driving dataset. Extensive experiments demonstrate that our approach outperforms previous methods in rendering texture details and motion areas while also producing a clean static background. Our code will be released at https://github.com/Luciferbobo/D4NeRF.

Differentiable Architecture Search (DARTS) has attracted considerable attention as a gradient-based Neural Architecture Search (NAS) method. Since the introduction of DARTS, there has been little work done on adapting the action space based on state-of-art architecture design principles for CNNs. In this work, we aim to address this gap by incrementally augmenting the DARTS search space with micro-design changes inspired by ConvNeXt and studying the trade-off between accuracy, evaluation layer count, and computational cost. To this end, we introduce the Pseudo-Inverted Bottleneck conv block intending to reduce the computational footprint of the inverted bottleneck block proposed in ConvNeXt. Our proposed architecture is much less sensitive to evaluation layer count and outperforms a DARTS network with similar size significantly, at layer counts as small as 2. Furthermore, with less layers, not only does it achieve higher accuracy with lower GMACs and parameter count, GradCAM comparisons show that our network is able to better detect distinctive features of target objects compared to DARTS.

The traditional statistical inference is static, in the sense that the estimate of the quantity of interest does not affect the future evolution of the quantity. In some sequential estimation problems however, the future values of the quantity to be estimated depend on the estimate of its current value. This type of estimation problems has been formulated as the dynamic inference problem. In this work, we formulate the Bayesian learning problem for dynamic inference, where the unknown quantity-generation model is assumed to be randomly drawn according to a random model parameter. We derive the optimal Bayesian learning rules, both offline and online, to minimize the inference loss. Moreover, learning for dynamic inference can serve as a meta problem, such that all familiar machine learning problems, including supervised learning, imitation learning and reinforcement learning, can be cast as its special cases or variants. Gaining a good understanding of this unifying meta problem thus sheds light on a broad spectrum of machine learning problems as well.