我们争辩说,当模型学习\ texit {good}表示时,我们应该有一个有价值的视角是,应该由人类类似地观察到模型的类似表示的输入。我们使用\ textit {表示反转}来生成映射到相同模型表示的多个输入,然后通过人类调查量化这些输入的感知相似性。我们的方法产生了模型与人类感知对齐的程度的衡量标准。使用这种对准度量,我们评估了用各种学习范例(例如〜监督和自我监督学习)和不同培训损失(标准和强大培训)培训的模型。我们的研究结果表明,具有人类感知的表现的对齐提供了对模型的品质的有用的额外见解。例如,我们发现与人类感知的对齐可以用作模型对不同模型对输出冲突的输入的模型预测的信任的量度。我们还发现模型的各种属性,如其架构,培训范式,培训损失和数据增强在与人类感知一致的学习陈述中起着重要作用。
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ICECUBE是一种用于检测1 GEV和1 PEV之间大气和天体中微子的光学传感器的立方公斤阵列,该阵列已部署1.45 km至2.45 km的南极的冰盖表面以下1.45 km至2.45 km。来自ICE探测器的事件的分类和重建在ICeCube数据分析中起着核心作用。重建和分类事件是一个挑战,这是由于探测器的几何形状,不均匀的散射和冰中光的吸收,并且低于100 GEV的光,每个事件产生的信号光子数量相对较少。为了应对这一挑战,可以将ICECUBE事件表示为点云图形,并将图形神经网络(GNN)作为分类和重建方法。 GNN能够将中微子事件与宇宙射线背景区分开,对不同的中微子事件类型进行分类,并重建沉积的能量,方向和相互作用顶点。基于仿真,我们提供了1-100 GEV能量范围的比较与当前ICECUBE分析中使用的当前最新最大似然技术,包括已知系统不确定性的影响。对于中微子事件分类,与当前的IceCube方法相比,GNN以固定的假阳性速率(FPR)提高了信号效率的18%。另外,GNN在固定信号效率下将FPR的降低超过8(低于半百分比)。对于能源,方向和相互作用顶点的重建,与当前最大似然技术相比,分辨率平均提高了13%-20%。当在GPU上运行时,GNN能够以几乎是2.7 kHz的中位数ICECUBE触发速率的速率处理ICECUBE事件,这打开了在在线搜索瞬态事件中使用低能量中微子的可能性。
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深度学习在学习高维数据的低维表示方面取得了巨大的成功。如果在感兴趣的数据中没有隐藏的低维结构,那么这一成功将是不可能的。这种存在是由歧管假设提出的,该假设指出数据在于固有维度低的未知流形。在本文中,我们认为该假设无法正确捕获数据中通常存在的低维结构。假设数据在于单个流形意味着整个数据空间的内在维度相同,并且不允许该空间的子区域具有不同数量的变异因素。为了解决这一缺陷,我们提出了多种假设的结合,该假设适应了非恒定固有维度的存在。我们从经验上验证了在常用图像数据集上的这一假设,发现确实应该允许内在维度变化。我们还表明,具有较高内在维度的类更难分类,以及如何使用这种见解来提高分类精度。然后,我们将注意力转移到该假设的影响下,在深层生成模型(DGM)的背景下。当前的大多数DGM都难以建模具有几个连接组件和/或不同固有维度的数据集建模。为了解决这些缺点,我们提出了群集的DGM,首先将数据聚集,然后在每个群集上训练DGM。我们表明,聚类的DGM可以模拟具有不同固有维度的多个连接组件,并在没有增加计算要求的情况下经验优于其非簇的非群体。
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在本文中,我们研究了多服务器边缘计算中基于区块链的联合学习(BFL)的新延迟优化问题。在此系统模型中,分布式移动设备(MDS)与一组Edge服务器(ESS)通信,以同时处理机器学习(ML)模型培训和阻止开采。为了协助ML模型培训用于资源受限的MD,我们制定了一种卸载策略,使MD可以将其数据传输到相关的ESS之一。然后,我们基于共识机制在边缘层上提出了一个新的分散的ML模型聚合解决方案,以通过基于对等(P2P)基于基于的区块链通信构建全局ML模型。区块链在MDS和ESS之间建立信任,以促进可靠的ML模型共享和合作共识形成,并能够快速消除由中毒攻击引起的操纵模型。我们将延迟感知的BFL作为优化,旨在通过联合考虑数据卸载决策,MDS的传输功率,MDS数据卸载,MDS的计算分配和哈希功率分配来最大程度地减少系统延迟。鉴于离散卸载和连续分配变量的混合作用空间,我们提出了一种具有参数化优势演员评论家算法的新型深度强化学习方案。从理论上讲,我们根据聚合延迟,迷你批量大小和P2P通信回合的数量来表征BFL的收敛属性。我们的数值评估证明了我们所提出的方案优于基线,从模型训练效率,收敛速度,系统潜伏期和对模型中毒攻击的鲁棒性方面。
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There are multiple scales of abstraction from which we can describe the same image, depending on whether we are focusing on fine-grained details or a more global attribute of the image. In brain mapping, learning to automatically parse images to build representations of both small-scale features (e.g., the presence of cells or blood vessels) and global properties of an image (e.g., which brain region the image comes from) is a crucial and open challenge. However, most existing datasets and benchmarks for neuroanatomy consider only a single downstream task at a time. To bridge this gap, we introduce a new dataset, annotations, and multiple downstream tasks that provide diverse ways to readout information about brain structure and architecture from the same image. Our multi-task neuroimaging benchmark (MTNeuro) is built on volumetric, micrometer-resolution X-ray microtomography images spanning a large thalamocortical section of mouse brain, encompassing multiple cortical and subcortical regions. We generated a number of different prediction challenges and evaluated several supervised and self-supervised models for brain-region prediction and pixel-level semantic segmentation of microstructures. Our experiments not only highlight the rich heterogeneity of this dataset, but also provide insights into how self-supervised approaches can be used to learn representations that capture multiple attributes of a single image and perform well on a variety of downstream tasks. Datasets, code, and pre-trained baseline models are provided at: https://mtneuro.github.io/ .
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The purpose of this work was to tackle practical issues which arise when using a tendon-driven robotic manipulator with a long, passive, flexible proximal section in medical applications. A separable robot which overcomes difficulties in actuation and sterilization is introduced, in which the body containing the electronics is reusable and the remainder is disposable. A control input which resolves the redundancy in the kinematics and a physical interpretation of this redundancy are provided. The effect of a static change in the proximal section angle on bending angle error was explored under four testing conditions for a sinusoidal input. Bending angle error increased for increasing proximal section angle for all testing conditions with an average error reduction of 41.48% for retension, 4.28% for hysteresis, and 52.35% for re-tension + hysteresis compensation relative to the baseline case. Two major sources of error in tracking the bending angle were identified: time delay from hysteresis and DC offset from the proximal section angle. Examination of these error sources revealed that the simple hysteresis compensation was most effective for removing time delay and re-tension compensation for removing DC offset, which was the primary source of increasing error. The re-tension compensation was also tested for dynamic changes in the proximal section and reduced error in the final configuration of the tip by 89.14% relative to the baseline case.
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Compliance in actuation has been exploited to generate highly dynamic maneuvers such as throwing that take advantage of the potential energy stored in joint springs. However, the energy storage and release could not be well-timed yet. On the contrary, for multi-link systems, the natural system dynamics might even work against the actual goal. With the introduction of variable stiffness actuators, this problem has been partially addressed. With a suitable optimal control strategy, the approximate decoupling of the motor from the link can be achieved to maximize the energy transfer into the distal link prior to launch. However, such continuous stiffness variation is complex and typically leads to oscillatory swing-up motions instead of clear launch sequences. To circumvent this issue, we investigate decoupling for speed maximization with a dedicated novel actuator concept denoted Bi-Stiffness Actuation. With this, it is possible to fully decouple the link from the joint mechanism by a switch-and-hold clutch and simultaneously keep the elastic energy stored. We show that with this novel paradigm, it is not only possible to reach the same optimal performance as with power-equivalent variable stiffness actuation, but even directly control the energy transfer timing. This is a major step forward compared to previous optimal control approaches, which rely on optimizing the full time-series control input.
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The previous fine-grained datasets mainly focus on classification and are often captured in a controlled setup, with the camera focusing on the objects. We introduce the first Fine-Grained Vehicle Detection (FGVD) dataset in the wild, captured from a moving camera mounted on a car. It contains 5502 scene images with 210 unique fine-grained labels of multiple vehicle types organized in a three-level hierarchy. While previous classification datasets also include makes for different kinds of cars, the FGVD dataset introduces new class labels for categorizing two-wheelers, autorickshaws, and trucks. The FGVD dataset is challenging as it has vehicles in complex traffic scenarios with intra-class and inter-class variations in types, scale, pose, occlusion, and lighting conditions. The current object detectors like yolov5 and faster RCNN perform poorly on our dataset due to a lack of hierarchical modeling. Along with providing baseline results for existing object detectors on FGVD Dataset, we also present the results of a combination of an existing detector and the recent Hierarchical Residual Network (HRN) classifier for the FGVD task. Finally, we show that FGVD vehicle images are the most challenging to classify among the fine-grained datasets.
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The task of reconstructing 3D human motion has wideranging applications. The gold standard Motion capture (MoCap) systems are accurate but inaccessible to the general public due to their cost, hardware and space constraints. In contrast, monocular human mesh recovery (HMR) methods are much more accessible than MoCap as they take single-view videos as inputs. Replacing the multi-view Mo- Cap systems with a monocular HMR method would break the current barriers to collecting accurate 3D motion thus making exciting applications like motion analysis and motiondriven animation accessible to the general public. However, performance of existing HMR methods degrade when the video contains challenging and dynamic motion that is not in existing MoCap datasets used for training. This reduces its appeal as dynamic motion is frequently the target in 3D motion recovery in the aforementioned applications. Our study aims to bridge the gap between monocular HMR and multi-view MoCap systems by leveraging information shared across multiple video instances of the same action. We introduce the Neural Motion (NeMo) field. It is optimized to represent the underlying 3D motions across a set of videos of the same action. Empirically, we show that NeMo can recover 3D motion in sports using videos from the Penn Action dataset, where NeMo outperforms existing HMR methods in terms of 2D keypoint detection. To further validate NeMo using 3D metrics, we collected a small MoCap dataset mimicking actions in Penn Action,and show that NeMo achieves better 3D reconstruction compared to various baselines.
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Rigorous guarantees about the performance of predictive algorithms are necessary in order to ensure their responsible use. Previous work has largely focused on bounding the expected loss of a predictor, but this is not sufficient in many risk-sensitive applications where the distribution of errors is important. In this work, we propose a flexible framework to produce a family of bounds on quantiles of the loss distribution incurred by a predictor. Our method takes advantage of the order statistics of the observed loss values rather than relying on the sample mean alone. We show that a quantile is an informative way of quantifying predictive performance, and that our framework applies to a variety of quantile-based metrics, each targeting important subsets of the data distribution. We analyze the theoretical properties of our proposed method and demonstrate its ability to rigorously control loss quantiles on several real-world datasets.
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