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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精确和高保真力控制对于与人类和未知环境相互作用的新一代机器人至关重要。移动机器人(例如可穿戴设备和腿部机器人)也必须轻巧才能完成其功能。已经提出了静液压传输,作为满足这两个具有挑战性要求的有前途的策略。在以前的出版物中,结果表明,使用磁性执行器(MR)执行器与静水透射率相结合,可提供高功率密度和出色的开环人类机器人相互作用。尽管如此,传输动力学和非线性摩擦仍会降低低频和高频下的开环力保真度。这封信比较了MR-Hydrstortic执行器系统的控制策略,以增加其扭矩保真度,该扭矩屈服于带宽(测量得出的扭矩参考)和透明度(最小化在机器人背后反射到最终效应器的不需要的力)。开发了四种控制方法并通过实验进行比较:(1)具有摩擦补偿的开环控制; (2)非集中压力反馈; (3)压力反馈; (4)LQGI状态反馈。还实施了抖动策略来平滑球螺钉摩擦。结果表明,方法(1),(2)和(3)可以提高性能,但面临妥协,而方法(4)可以同时改善所有指标。这些结果表明,使用控制方案使用束缚架构来改善机器人的力控制性能的潜力,从而解决了传输动力学和摩擦等问题。
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可穿戴机器人受到执行器表演的限制,因为它们必须承担自己的电力系统和能源的重量。本文探讨了利用混合模式通过使用液压阀动态重新配置静液压执行器的连接来利用混合模式以轻巧有效的系统来满足多个操作点的想法。分析的机会包括1)在高度齿轮电源或快速电源之间切换,2)动态连接能量蓄能器,3)使用锁定机制进行固定。基于膝盖外骨骼案例研究分析,结果表明,齿轮比之间的切换可以导致更轻,更有效的执行器。此外,结果表明,使用累加器提供预紧力的连续力具有巨大的质量潜力,但如果用作短瞬态的功率助推器,则不会显着降低质量。最后,如果工作周期频繁停止,使用锁定阀可以稍微降低电池质量。提出的多模式方案的操作原理用一氧化碳原型证明。
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超级机器人四肢(SRL)是可穿戴的机器人,通过充当同事,到达物体,支撑人的武器等来增强人类能力。但是,现有的SRL缺乏可控制互动力所需的机械背景和带宽作为绘画,操纵脆弱的物体等。具有高带宽的高度背景,而最小化重量则带来了由常规电磁执行器的有限表现施加的重大技术挑战。本文研究了使用磁性(MR)离合器耦合到低摩擦式静液传动的可行性,以提供高功能强大但可轻巧,可控制的SRL。设计和建造了2.7千克二线可穿戴机器人手臂。肩膀和肘关节的设计可提供39和25 nm,运动范围为115和180 {\ deg}。在一氧化基督测试台上进行的实验研究并在分析上进行了验证,即使在与外部阻抗相互作用时,也表明了高力带宽(> 25 Hz),并且能够控制相互作用的能力。此外,研究并通过实验研究了三种力对照方法:开环,闭环力和压力上的闭环。所有三种方法均显示为有效。总体而言,拟议的MR-Hydrstoratic致动系统非常适合与人类和环境相互作用的轻量级SRL,从而增加了无法预测的干扰。
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$ \ mathbf {perive} $:使用人工智能(AI)到:(1)从相对较大的人群中利用视神经头(ONH)的生物力学知识; (2)评估ONH的单个光学相干断层扫描(OCT)扫描的稳健性; (3)确定哪些关键的三维(3D)结构特征使给定的ONH稳健。 $ \ Mathbf {Design} $:回顾性横断面研究。 $ \ mathbf {Methods} $:316个受试者通过Ophthalmo-Dynamometry在急性眼内和之后与OCT成像。然后将IOP诱导的椎板胶状变形映射为3D,并用于对ONH进行分类。 LC变形高于4%的人被认为是脆弱的,而变形较低的人则较低4%。从这些数据中学习,我们比较了三种AI算法,以严格地从基线(未呈现的)OCT卷中预测鲁棒性:(1)随机森林分类器; (2)自动编码器; (3)动态图CNN(DGCNN)。后一种算法还使我们能够确定哪些关键的3D结构特征使给定的智能稳定。 $ \ mathbf {结果} $:所有3种方法都能够单独预测3D结构信息的稳健性,而无需执行生物力学测试。 DGCNN(接收器操作曲线下的区域[AUC]:0.76 $ \ pm $ 0.08)的表现优于自动编码器(AUC:0.70 $ \ pm $ 0.07)和随机森林分类器(AUC:0.69 $ \ pm $ 0.05)。有趣的是,为了评估稳健性,DGCNN主要使用了巩膜和LC插入部位的信息。 $ \ mathbf {结论} $:我们提出了一种AI驱动的方法,可以仅从ONH的单个OCT扫描中评估给定ONH的稳健性,而无需进行生物力学测试。纵向研究应确定ONH鲁棒性是否可以帮助我们确定快速的视野损失进展者。
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目的:(1)开发深度学习算法,以识别3D光学相干断层扫描(OCT)扫描中的视神经头(ONH)的主要组织结构; (2)利用这些信息在健康,光盘博森(奇数)和乳头膜ONHS之间鲁棒地区分。由于高颅内压(51只眼)和健康对照(100只眼睛),这是一种横截面对比研究,由于高颅内压(51只眼睛),以及健康的对照(100只眼)。使用OCT获得ONH的3D扫描,然后加工以改善深层组织可见性。首先,使用984 B-Scans(从130只眼睛)开发了深度学习算法,以识别:主要的神经/结缔组织和奇数区域。使用骰子系数(DC)评估我们的算法的性能。在第2步骤中,使用1500Ct卷设计了一个分类算法(随机林),以严格从其德鲁森和普拉拉马那肿胀得分(来自细分)来执行3级分类(1:奇数,2:Papilledema,3:健康) )。为了评估性能,我们报告了每个类的接收器操作特征曲线(AUC)下的区域。我们的分割算法能够在存在时隔离神经和结缔组织和奇数区域。这是在测试集上的平均DC为0.93 $ 0.03的平均直流,相应于良好性能。分类是用高AUC的分类,即检测奇数,0.99美元0.01 0.01美元,用于检测Papilledema的0.99美元,0.98美元$ 0.02用于检测健康的ONH。我们的AI方法可以使用单个OCT扫描来准确地歧视奇数乳头。我们的分类表现非常出色,有需要在更大的人口中验证。我们的方法可能有可能建立10月作为神经眼科诊断成像的主干。
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目的:评估中央视网膜血管躯干及其分支(CRVT&B)的三维(3D)结构构型是否可用作青光眼的诊断标志物。方法:我们训练了深度学习网络,从光神经头(ONH)的光学相干断层扫描(OCT)体积的B-Scans自动分割CRVT&B。随后,使用从OCT体积中提取的CRVT&B的结构构型,两种不同的方法用于青光眼诊断。在第一种方法中,我们旨在仅使用CNN的3D CNN和CRVT&B的3D结构提供诊断。对于第二种方法,我们将CRVT&B的3D结构投射到三个平面上以获得2D图像,然后使用2D CNN进行诊断。使用骰子系数评估分割精度,而使用接收器操作特性曲线(AUC)下的区域评估诊断准确度。 CRVT&B的诊断性能也与视网膜神经纤维层(RNFL)厚度进行了比较。结果:我们的分割网络能够从OCT扫描有效地分段视网膜血管。在测试集上,我们实现了0.81 \ PM0.07的骰子系数。 3D和2D诊断网络能够将青光眼与非青光眼受试者区分别分别区分82.7%和83.3%的精度。 CRVT&B的相应AUC为0.89和0.90,高于用RNFL厚度获得的0.90℃。结论:我们的工作表明,CRVT&B的诊断功能优于金标 - 标准的青光眼参数,即RNFL厚度。我们的作品还建议主要视网膜血管形成骨架 - 其配置可以代表主要的ONH结构变化,通常观察到青光眼的开发和进展。
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Real-world robotic grasping can be done robustly if a complete 3D Point Cloud Data (PCD) of an object is available. However, in practice, PCDs are often incomplete when objects are viewed from few and sparse viewpoints before the grasping action, leading to the generation of wrong or inaccurate grasp poses. We propose a novel grasping strategy, named 3DSGrasp, that predicts the missing geometry from the partial PCD to produce reliable grasp poses. Our proposed PCD completion network is a Transformer-based encoder-decoder network with an Offset-Attention layer. Our network is inherently invariant to the object pose and point's permutation, which generates PCDs that are geometrically consistent and completed properly. Experiments on a wide range of partial PCD show that 3DSGrasp outperforms the best state-of-the-art method on PCD completion tasks and largely improves the grasping success rate in real-world scenarios. The code and dataset will be made available upon acceptance.
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Model estimates obtained from traditional subspace identification methods may be subject to significant variance. This elevated variance is aggravated in the cases of large models or of a limited sample size. Common solutions to reduce the effect of variance are regularized estimators, shrinkage estimators and Bayesian estimation. In the current work we investigate the latter two solutions, which have not yet been applied to subspace identification. Our experimental results show that our proposed estimators may reduce the estimation risk up to $40\%$ of that of traditional subspace methods.
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This report summarizes the work carried out by the authors during the Twelfth Montreal Industrial Problem Solving Workshop, held at Universit\'e de Montr\'eal in August 2022. The team tackled a problem submitted by CBC/Radio-Canada on the theme of Automatic Text Simplification (ATS).
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