Recent investigations on rotation invariance for 3D point clouds have been devoted to devising rotation-invariant feature descriptors or learning canonical spaces where objects are semantically aligned. Examinations of learning frameworks for invariance have seldom been looked into. In this work, we review rotation invariance in terms of point cloud registration and propose an effective framework for rotation invariance learning via three sequential stages, namely rotation-invariant shape encoding, aligned feature integration, and deep feature registration. We first encode shape descriptors constructed with respect to reference frames defined over different scales, e.g., local patches and global topology, to generate rotation-invariant latent shape codes. Within the integration stage, we propose Aligned Integration Transformer to produce a discriminative feature representation by integrating point-wise self- and cross-relations established within the shape codes. Meanwhile, we adopt rigid transformations between reference frames to align the shape codes for feature consistency across different scales. Finally, the deep integrated feature is registered to both rotation-invariant shape codes to maximize feature similarities, such that rotation invariance of the integrated feature is preserved and shared semantic information is implicitly extracted from shape codes. Experimental results on 3D shape classification, part segmentation, and retrieval tasks prove the feasibility of our work. Our project page is released at: https://rotation3d.github.io/.
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The number of international benchmarking competitions is steadily increasing in various fields of machine learning (ML) research and practice. So far, however, little is known about the common practice as well as bottlenecks faced by the community in tackling the research questions posed. To shed light on the status quo of algorithm development in the specific field of biomedical imaging analysis, we designed an international survey that was issued to all participants of challenges conducted in conjunction with the IEEE ISBI 2021 and MICCAI 2021 conferences (80 competitions in total). The survey covered participants' expertise and working environments, their chosen strategies, as well as algorithm characteristics. A median of 72% challenge participants took part in the survey. According to our results, knowledge exchange was the primary incentive (70%) for participation, while the reception of prize money played only a minor role (16%). While a median of 80 working hours was spent on method development, a large portion of participants stated that they did not have enough time for method development (32%). 25% perceived the infrastructure to be a bottleneck. Overall, 94% of all solutions were deep learning-based. Of these, 84% were based on standard architectures. 43% of the respondents reported that the data samples (e.g., images) were too large to be processed at once. This was most commonly addressed by patch-based training (69%), downsampling (37%), and solving 3D analysis tasks as a series of 2D tasks. K-fold cross-validation on the training set was performed by only 37% of the participants and only 50% of the participants performed ensembling based on multiple identical models (61%) or heterogeneous models (39%). 48% of the respondents applied postprocessing steps.
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对于不同的任务,已经越来越多地研究了一般点云,并且提出了最近的基于变换器的网络,用于点云分析。然而,医疗点云几乎没有相关的作品,这对疾病检测和治疗很重要。在这项工作中,我们提出了专门用于医疗点云的关注模型,即3D医疗点变压器(3Dmedpt),以检查复杂的生物结构。通过增强上下文信息并在查询时总结本地响应,我们的注意模块可以捕获本地上下文和全局内容功能交互。然而,医疗数据的培训样本不足可能导致特征学习差,因此我们应用位置嵌入,以学习准确的局部几何和多图形推理(MGR)来检查通过通道图的全局知识传播,以丰富特征表示。在数据集内进行的实验证明了3DMedpt的优越性,在那里我们达到了最佳分类和分割结果。此外,我们的方法的有希望的泛化能力在一般的3D点云基准测试中验证:ModelNet40和ShapenetPart。代码即将发布。
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Given a resource-rich source graph and a resource-scarce target graph, how can we effectively transfer knowledge across graphs and ensure a good generalization performance? In many high-impact domains (e.g., brain networks and molecular graphs), collecting and annotating data is prohibitively expensive and time-consuming, which makes domain adaptation an attractive option to alleviate the label scarcity issue. In light of this, the state-of-the-art methods focus on deriving domain-invariant graph representation that minimizes the domain discrepancy. However, it has recently been shown that a small domain discrepancy loss may not always guarantee a good generalization performance, especially in the presence of disparate graph structures and label distribution shifts. In this paper, we present TRANSNET, a generic learning framework for augmenting knowledge transfer across graphs. In particular, we introduce a novel notion named trinity signal that can naturally formulate various graph signals at different granularity (e.g., node attributes, edges, and subgraphs). With that, we further propose a domain unification module together with a trinity-signal mixup scheme to jointly minimize the domain discrepancy and augment the knowledge transfer across graphs. Finally, comprehensive empirical results show that TRANSNET outperforms all existing approaches on seven benchmark datasets by a significant margin.
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Rising usage of deep neural networks to perform decision making in critical applications like medical diagnosis and financial analysis have raised concerns regarding their reliability and trustworthiness. As automated systems become more mainstream, it is important their decisions be transparent, reliable and understandable by humans for better trust and confidence. To this effect, concept-based models such as Concept Bottleneck Models (CBMs) and Self-Explaining Neural Networks (SENN) have been proposed which constrain the latent space of a model to represent high level concepts easily understood by domain experts in the field. Although concept-based models promise a good approach to both increasing explainability and reliability, it is yet to be shown if they demonstrate robustness and output consistent concepts under systematic perturbations to their inputs. To better understand performance of concept-based models on curated malicious samples, in this paper, we aim to study their robustness to adversarial perturbations, which are also known as the imperceptible changes to the input data that are crafted by an attacker to fool a well-learned concept-based model. Specifically, we first propose and analyze different malicious attacks to evaluate the security vulnerability of concept based models. Subsequently, we propose a potential general adversarial training-based defense mechanism to increase robustness of these systems to the proposed malicious attacks. Extensive experiments on one synthetic and two real-world datasets demonstrate the effectiveness of the proposed attacks and the defense approach.
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3D场景由大量背景点主导,这对于主要需要集中在前景对象的检测任务是多余的。在本文中,我们分析了现有的稀疏3D CNN的主要组成部分,发现3D CNN忽略了数据的冗余,并在下降过程中进一步扩大了数据,这带来了大量的多余和不必要的计算间开销。受到这一点的启发,我们提出了一个名为“空间修剪稀疏卷积”(SPS-CONV)的新型卷积操作员,其中包括两个变体,空间修剪的Submanifold稀疏卷积(SPSS-CONV)和空间修剪的常规稀疏卷积(SPRS-CONV),包括这是基于动态确定冗余降低关键领域的想法。我们验证该幅度可以作为确定摆脱基于学习方法的额外计算的关键领域的重要提示。提出的模块可以轻松地将其纳入现有的稀疏3D CNN中,而无需额外的架构修改。关于Kitti,Waymo和Nuscenes数据集的广泛实验表明,我们的方法可以在不损害性能的情况下实现超过50%的GFLOPS。
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传统的多播路由方法在构建多播树时存在一些问题,例如对网络状态信息的访问有限,对网络的动态和复杂变化的适应性不佳以及不灵活的数据转发。为了解决这些缺陷,软件定义网络(SDN)中的最佳多播路由问题是根据多目标优化问题量身定制的,以及基于深Q网络(DQN)深度强化学习(DQN)的智能多播路由算法DRL-M4MR( DRL)方法旨在构建SDN中的多播树。首先,通过组合SDN的全局视图和控制,将多播树状态矩阵,链路带宽矩阵,链路延迟矩阵和链路延迟损耗矩阵设计为DRL代理的状态空间。其次,代理的动作空间是网络中的所有链接,而动作选择策略旨在将链接添加到四种情况下的当前多播树。第三,单步和最终奖励功能表格旨在指导智能以做出决定以构建最佳多播树。实验结果表明,与现有算法相比,DRL-M4MR的多播树结构可以在训练后获得更好的带宽,延迟和数据包损耗率,并且可以在动态网络环境中做出更智能的多播路由决策。
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2D CNN和视觉变压器(VIT)的最新进展表明,大型内核对于足够的接受场和高性能至关重要。受这些文献的启发,我们研究了3D大型设计的可行性和挑战。我们证明,在3D CNN中应用大型卷积内核在性能和效率方面都有更多困难。在2D CNN中运行良好的现有技术在3D网络中无效,包括流行的深度卷积。为了克服这些障碍,我们介绍了空间团体卷积及其大内核模块(SW-LK块)。它避免了幼稚3D大核的优化和效率问题。我们的大型内核3D CNN网络,即grounkernel3d,对各种3D任务(包括语义分割和对象检测)产生了非平凡的改进。值得注意的是,它在ScannETV2语义细分和72.8%的NDS NUSCENES对象检测基准上获得了73.9%的MIOU,在Nuscenes Lidar Leadar排行榜上排名第一。具有简单的多模式融合,将其进一步提高到74.2%NDS。与其CNN和Transformer对应物相比,bamekernel3d获得了可比或优越的结果。我们第一次表明,大型内核是可行的,对于3D网络至关重要。
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在点击率(CTR)预测方案中,用户的顺序行为很好地利用来捕获最近文献中的用户兴趣。然而,尽管正在广泛研究,但这些顺序方法仍然存在三个限制。首先,现有方法主要利用对用户行为的注意,这并不总是适用于CTR预测,因为用户经常点击与任何历史行为无关的新产品。其次,在真实场景中,很久以前存在许多具有运营的用户,但最近的次数相对不活跃。因此,难以通过早期行为精确地捕获用户的当前偏好。第三,不同特征子空间中用户历史行为的多个表示主要被忽略。为了解决这些问题,我们提出了一种多互动关注网络(Mian),全面提取各种细粒度特征之间的潜在关系(例如,性别,年龄和用户档案)。具体而言,MIAN包含多交互式层(MIL),其集成了三个本地交互模块,通过顺序行为捕获用户偏好的多个表示,并同时利用细粒度的用户特定的以及上下文信息。此外,我们设计了一个全局交互模块(GIM)来学习高阶交互,平衡多个功能的不同影响。最后,脱机实验结果来自三个数据集,以及在大型推荐系统中的在线A / B测试,展示了我们提出的方法的有效性。
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Unsupervised domain adaptation (UDA) for semantic segmentation is a promising task freeing people from heavy annotation work. However, domain discrepancies in low-level image statistics and high-level contexts compromise the segmentation performance over the target domain. A key idea to tackle this problem is to perform both image-level and feature-level adaptation jointly. Unfortunately, there is a lack of such unified approaches for UDA tasks in the existing literature. This paper proposes a novel UDA pipeline for semantic segmentation that unifies image-level and feature-level adaptation. Concretely, for image-level domain shifts, we propose a global photometric alignment module and a global texture alignment module that align images in the source and target domains in terms of image-level properties. For feature-level domain shifts, we perform global manifold alignment by projecting pixel features from both domains onto the feature manifold of the source domain; and we further regularize category centers in the source domain through a category-oriented triplet loss and perform target domain consistency regularization over augmented target domain images. Experimental results demonstrate that our pipeline significantly outperforms previous methods. In the commonly tested GTA5$\rightarrow$Cityscapes task, our proposed method using Deeplab V3+ as the backbone surpasses previous SOTA by 8%, achieving 58.2% in mIoU.
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