基于草图的3D形状检索(SBSR)是一项重要但艰巨的任务,近年来引起了越来越多的关注。现有方法在限制设置中解决了该问题,而无需适当模拟真实的应用程序方案。为了模仿现实的设置,在此曲目中,我们采用了不同级别的绘图技能的业余爱好者以及各种3D形状的大规模草图,不仅包括CAD型号,而且还可以从真实对象扫描的模型。我们定义了两个SBSR任务,并构建了两个基准,包括46,000多个CAD型号,1,700个现实型号和145,000个草图。四个团队参加了这一轨道,并为这两个任务提交了15次跑步,由7个常用指标评估。我们希望,基准,比较结果和开源评估法会在3D对象检索社区中促进未来的研究。
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Modern deep neural networks have achieved superhuman performance in tasks from image classification to game play. Surprisingly, these various complex systems with massive amounts of parameters exhibit the same remarkable structural properties in their last-layer features and classifiers across canonical datasets. This phenomenon is known as "Neural Collapse," and it was discovered empirically by Papyan et al. \cite{Papyan20}. Recent papers have theoretically shown the global solutions to the training network problem under a simplified "unconstrained feature model" exhibiting this phenomenon. We take a step further and prove the Neural Collapse occurrence for deep linear network for the popular mean squared error (MSE) and cross entropy (CE) loss. Furthermore, we extend our research to imbalanced data for MSE loss and present the first geometric analysis for Neural Collapse under this setting.
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We present a Machine Learning (ML) study case to illustrate the challenges of clinical translation for a real-time AI-empowered echocardiography system with data of ICU patients in LMICs. Such ML case study includes data preparation, curation and labelling from 2D Ultrasound videos of 31 ICU patients in LMICs and model selection, validation and deployment of three thinner neural networks to classify apical four-chamber view. Results of the ML heuristics showed the promising implementation, validation and application of thinner networks to classify 4CV with limited datasets. We conclude this work mentioning the need for (a) datasets to improve diversity of demographics, diseases, and (b) the need of further investigations of thinner models to be run and implemented in low-cost hardware to be clinically translated in the ICU in LMICs. The code and other resources to reproduce this work are available at https://github.com/vital-ultrasound/ai-assisted-echocardiography-for-low-resource-countries.
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Collecting large-scale medical datasets with fully annotated samples for training of deep networks is prohibitively expensive, especially for 3D volume data. Recent breakthroughs in self-supervised learning (SSL) offer the ability to overcome the lack of labeled training samples by learning feature representations from unlabeled data. However, most current SSL techniques in the medical field have been designed for either 2D images or 3D volumes. In practice, this restricts the capability to fully leverage unlabeled data from numerous sources, which may include both 2D and 3D data. Additionally, the use of these pre-trained networks is constrained to downstream tasks with compatible data dimensions. In this paper, we propose a novel framework for unsupervised joint learning on 2D and 3D data modalities. Given a set of 2D images or 2D slices extracted from 3D volumes, we construct an SSL task based on a 2D contrastive clustering problem for distinct classes. The 3D volumes are exploited by computing vectored embedding at each slice and then assembling a holistic feature through deformable self-attention mechanisms in Transformer, allowing incorporating long-range dependencies between slices inside 3D volumes. These holistic features are further utilized to define a novel 3D clustering agreement-based SSL task and masking embedding prediction inspired by pre-trained language models. Experiments on downstream tasks, such as 3D brain segmentation, lung nodule detection, 3D heart structures segmentation, and abnormal chest X-ray detection, demonstrate the effectiveness of our joint 2D and 3D SSL approach. We improve plain 2D Deep-ClusterV2 and SwAV by a significant margin and also surpass various modern 2D and 3D SSL approaches.
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Graph Neural Networks (GNNs) had been demonstrated to be inherently susceptible to the problems of over-smoothing and over-squashing. These issues prohibit the ability of GNNs to model complex graph interactions by limiting their effectiveness at taking into account distant information. Our study reveals the key connection between the local graph geometry and the occurrence of both of these issues, thereby providing a unified framework for studying them at a local scale using the Ollivier's Ricci curvature. Based on our theory, a number of principled methods are proposed to alleviate the over-smoothing and over-squashing issues.
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This paper presents a two-step algorithm for online trajectory planning in indoor environments with unknown obstacles. In the first step, sampling-based path planning techniques such as the optimal Rapidly exploring Random Tree (RRT*) algorithm and the Line-of-Sight (LOS) algorithm are employed to generate a collision-free path consisting of multiple waypoints. Then, in the second step, constrained quadratic programming is utilized to compute a smooth trajectory that passes through all computed waypoints. The main contribution of this work is the development of a flexible trajectory planning framework that can detect changes in the environment, such as new obstacles, and compute alternative trajectories in real time. The proposed algorithm actively considers all changes in the environment and performs the replanning process only on waypoints that are occupied by new obstacles. This helps to reduce the computation time and realize the proposed approach in real time. The feasibility of the proposed algorithm is evaluated using the Intel Aero Ready-to-Fly (RTF) quadcopter in simulation and in a real-world experiment.
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Solving the analytical inverse kinematics (IK) of redundant manipulators in real time is a difficult problem in robotics since its solution for a given target pose is not unique. Moreover, choosing the optimal IK solution with respect to application-specific demands helps to improve the robustness and to increase the success rate when driving the manipulator from its current configuration towards a desired pose. This is necessary, especially in high-dynamic tasks like catching objects in mid-flights. To compute a suitable target configuration in the joint space for a given target pose in the trajectory planning context, various factors such as travel time or manipulability must be considered. However, these factors increase the complexity of the overall problem which impedes real-time implementation. In this paper, a real-time framework to compute the analytical inverse kinematics of a redundant robot is presented. To this end, the analytical IK of the redundant manipulator is parameterized by so-called redundancy parameters, which are combined with a target pose to yield a unique IK solution. Most existing works in the literature either try to approximate the direct mapping from the desired pose of the manipulator to the solution of the IK or cluster the entire workspace to find IK solutions. In contrast, the proposed framework directly learns these redundancy parameters by using a neural network (NN) that provides the optimal IK solution with respect to the manipulability and the closeness to the current robot configuration. Monte Carlo simulations show the effectiveness of the proposed approach which is accurate and real-time capable ($\approx$ \SI{32}{\micro\second}) on the KUKA LBR iiwa 14 R820.
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This work proposes a novel singularity avoidance approach for real-time trajectory optimization based on known singular configurations. The focus of this work lies on analyzing kinematically singular configurations for three robots with different kinematic structures, i.e., the Comau Racer 7-1.4, the KUKA LBR iiwa R820, and the Franka Emika Panda, and exploiting these configurations in form of tailored potential functions for singularity avoidance. Monte Carlo simulations of the proposed method and the commonly used manipulability maximization approach are performed for comparison. The numerical results show that the average computing time can be reduced and shorter trajectories in both time and path length are obtained with the proposed approach
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切成薄片的Wasserstein(SW)距离已在不同的应用程序场景中广泛使用,因为它可以缩放到大量的支撑量,而不会受到维数的诅咒。切成薄片的瓦斯坦距离的值是通过radon变换(RT)获得的原始度量的一维表示(投影)之间运输成本的平均值。尽管估计切成薄片的瓦斯坦族的支持效率,但仍需要在高维环境中进行相对较大的预测。因此,对于与维度相比,支撑次数相对较少的应用,例如,使用微型批量方法的几个深度学习应用,radon transform的矩阵乘法中的复杂性成为主要计算瓶颈。为了解决这个问题,我们建议通过线性和随机组合少量的预测来得出预测,这些预测被称为瓶颈预测。我们通过引入层次ra transform(HRT)来解释这些投影的用法,该层rad rad transform(HRT)是通过递归应用radon变换变体构建的。然后,我们将方法制定为措施之间的新指标,该指标命名为分层切片瓦斯坦(HSW)距离。通过证明HRT的注入性,我们得出了HSW的指标。此外,我们研究了HSW的理论特性,包括其与SW变体的联系及其计算和样品复杂性。最后,我们将HSW的计算成本和生成质量与常规SW进行比较,使用包括CIFAR10,Celeba和Tiny Imagenet在内的各种基准数据集进行深层生成建模的任务。
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尽管在过去的几年中取得了重大进展,但歧义仍然是面部表情识别(FER)的关键挑战。它可能导致嘈杂和不一致的注释,这阻碍了现实世界中深度学习模型的性能。在本文中,我们提出了一种新的不确定性标签分布学习方法,以提高深层模型的鲁棒性,以防止不确定性和歧义。我们利用价值空间中的邻里信息来适应培训训练样本的情绪分布。我们还考虑提供的标签将其纳入标签分布时的不确定性。我们的方法可以轻松地集成到深层网络中,以获得更多的培训监督并提高识别准确性。在各种嘈杂和模棱两可的环境下,在几个数据集上进行了密集的实验表明,我们的方法取得了竞争成果,并且超出了最新的最新方法。我们的代码和模型可在https://github.com/minhnhatvt/label-distribution-learning-fer-tf上找到。
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