随着空间的尺寸增加,在真实数据中分类高维形状的问题在复杂性中增长。对于识别不同几何形状的凸形形状的情况,最近提出了一种新的分类框架,其中使用一种称为射线的一组一维表示的交叉点,其中具有形状的边界来识别特定几何形状。基于射线的分类(RBC)已经使用两维和三维形状的合成数据集进行了经验验证的(Zwolak等人。在第三讲习班关于机器学习和物理科学(Neurips 2020),温哥华,加拿大的第三次研讨会的程序中[ arxiv:2010年12月11日,2010年12月11日,最近也已经通过实验验证(Zwolak等,Prx量子2:020335,2021)。在这里,我们建立了由关键角度度量定义的形状分类所需的光线数量的绑定,用于任意凸形形状。对于两个维度,我们在形状的长度,直径和外部角度方面导出了射线数量的下限。对于$ \ mathbb {r} ^ n $的凸多台,我们将此结果概括为与二向角度的函数和多边形面的几何参数给出的类似绑定。该结果使得能够使用比体积或基于表面的方法基本更少的数据元素估计高维形状的不同方法。
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Remote sensing imagery provides comprehensive views of the Earth, where different sensors collect complementary data at different spatial scales. Large, pretrained models are commonly finetuned with imagery that is heavily augmented to mimic different conditions and scales, with the resulting models used for various tasks with imagery from a range of spatial scales. Such models overlook scale-specific information in the data. In this paper, we present Scale-MAE, a pretraining method that explicitly learns relationships between data at different, known scales throughout the pretraining process. Scale-MAE pretrains a network by masking an input image at a known input scale, where the area of the Earth covered by the image determines the scale of the ViT positional encoding, not the image resolution. Scale-MAE encodes the masked image with a standard ViT backbone, and then decodes the masked image through a bandpass filter to reconstruct low/high frequency images at lower/higher scales. We find that tasking the network with reconstructing both low/high frequency images leads to robust multiscale representations for remote sensing imagery. Scale-MAE achieves an average of a $5.0\%$ non-parametric kNN classification improvement across eight remote sensing datasets compared to current state-of-the-art and obtains a $0.9$ mIoU to $3.8$ mIoU improvement on the SpaceNet building segmentation transfer task for a range of evaluation scales.
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By transferring knowledge from large, diverse, task-agnostic datasets, modern machine learning models can solve specific downstream tasks either zero-shot or with small task-specific datasets to a high level of performance. While this capability has been demonstrated in other fields such as computer vision, natural language processing or speech recognition, it remains to be shown in robotics, where the generalization capabilities of the models are particularly critical due to the difficulty of collecting real-world robotic data. We argue that one of the keys to the success of such general robotic models lies with open-ended task-agnostic training, combined with high-capacity architectures that can absorb all of the diverse, robotic data. In this paper, we present a model class, dubbed Robotics Transformer, that exhibits promising scalable model properties. We verify our conclusions in a study of different model classes and their ability to generalize as a function of the data size, model size, and data diversity based on a large-scale data collection on real robots performing real-world tasks. The project's website and videos can be found at robotics-transformer.github.io
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Point-of-Care Ultrasound (POCUS) refers to clinician-performed and interpreted ultrasonography at the patient's bedside. Interpreting these images requires a high level of expertise, which may not be available during emergencies. In this paper, we support POCUS by developing classifiers that can aid medical professionals by diagnosing whether or not a patient has pneumothorax. We decomposed the task into multiple steps, using YOLOv4 to extract relevant regions of the video and a 3D sparse coding model to represent video features. Given the difficulty in acquiring positive training videos, we trained a small-data classifier with a maximum of 15 positive and 32 negative examples. To counteract this limitation, we leveraged subject matter expert (SME) knowledge to limit the hypothesis space, thus reducing the cost of data collection. We present results using two lung ultrasound datasets and demonstrate that our model is capable of achieving performance on par with SMEs in pneumothorax identification. We then developed an iOS application that runs our full system in less than 4 seconds on an iPad Pro, and less than 8 seconds on an iPhone 13 Pro, labeling key regions in the lung sonogram to provide interpretable diagnoses.
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Supervised machine learning-based medical image computing applications necessitate expert label curation, while unlabelled image data might be relatively abundant. Active learning methods aim to prioritise a subset of available image data for expert annotation, for label-efficient model training. We develop a controller neural network that measures priority of images in a sequence of batches, as in batch-mode active learning, for multi-class segmentation tasks. The controller is optimised by rewarding positive task-specific performance gain, within a Markov decision process (MDP) environment that also optimises the task predictor. In this work, the task predictor is a segmentation network. A meta-reinforcement learning algorithm is proposed with multiple MDPs, such that the pre-trained controller can be adapted to a new MDP that contains data from different institutes and/or requires segmentation of different organs or structures within the abdomen. We present experimental results using multiple CT datasets from more than one thousand patients, with segmentation tasks of nine different abdominal organs, to demonstrate the efficacy of the learnt prioritisation controller function and its cross-institute and cross-organ adaptability. We show that the proposed adaptable prioritisation metric yields converging segmentation accuracy for the novel class of kidney, unseen in training, using between approximately 40\% to 60\% of labels otherwise required with other heuristic or random prioritisation metrics. For clinical datasets of limited size, the proposed adaptable prioritisation offers a performance improvement of 22.6\% and 10.2\% in Dice score, for tasks of kidney and liver vessel segmentation, respectively, compared to random prioritisation and alternative active sampling strategies.
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This paper is a technical overview of DeepMind and Google's recent work on reinforcement learning for controlling commercial cooling systems. Building on expertise that began with cooling Google's data centers more efficiently, we recently conducted live experiments on two real-world facilities in partnership with Trane Technologies, a building management system provider. These live experiments had a variety of challenges in areas such as evaluation, learning from offline data, and constraint satisfaction. Our paper describes these challenges in the hope that awareness of them will benefit future applied RL work. We also describe the way we adapted our RL system to deal with these challenges, resulting in energy savings of approximately 9% and 13% respectively at the two live experiment sites.
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Large language models (LLMs) have been shown to be able to perform new tasks based on a few demonstrations or natural language instructions. While these capabilities have led to widespread adoption, most LLMs are developed by resource-rich organizations and are frequently kept from the public. As a step towards democratizing this powerful technology, we present BLOOM, a 176B-parameter open-access language model designed and built thanks to a collaboration of hundreds of researchers. BLOOM is a decoder-only Transformer language model that was trained on the ROOTS corpus, a dataset comprising hundreds of sources in 46 natural and 13 programming languages (59 in total). We find that BLOOM achieves competitive performance on a wide variety of benchmarks, with stronger results after undergoing multitask prompted finetuning. To facilitate future research and applications using LLMs, we publicly release our models and code under the Responsible AI License.
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医学图像分割模型的性能指标用于衡量参考注释和预测之间的一致性。在开发此类模型中,使用了一组通用指标,以使结果更具可比性。但是,公共数据集中的分布与临床实践中遇到的案例之间存在不匹配。许多常见的指标无法衡量这种不匹配的影响,尤其是对于包含不确定,小或空参考注释的临床数据集。因此,可能无法通过此类指标来验证模型在临床上有意义的一致性。评估临床价值的维度包括独立于参考注释量的大小,考虑参考注释的不确定性,体积计和/或位置一致性的奖励以及对空参考注释正确分类的奖励。与普通的公共数据集不同,我们的内部数据集更具代表性。它包含不确定的,小或空的参考注释。我们研究了有关深度学习框架的预测的公开度量指标,以确定哪些设置共同指标可提供有意义的结果。我们将公共基准数据集进行比较而没有不确定,小或空参考注释。该代码将发布。
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在这项研究中,将放射学方法扩展到用于组织分类的光学荧光分子成像数据,称为“验光”。荧光分子成像正在出现在头颈部鳞状细胞癌(HNSCC)切除期间的精确手术引导。然而,肿瘤到正常的组织对比与靶分子表皮生长因子受体(EGFR)的异质表达的内在生理局限性混淆。验光学试图通过探测荧光传达的EGFR表达中的质地模式差异来改善肿瘤识别。从荧光图像样品中提取了总共1,472个标准化的验光特征。涉及支持矢量机分类器的监督机器学习管道接受了25个顶级功能的培训,这些功能由最小冗余最大相关标准选择。通过将切除组织的图像贴片分类为组织学确认的恶性肿瘤状态,将模型预测性能与荧光强度阈值方法进行了比较。与荧光强度阈值方法相比,验光方法在所有测试集样品中提供了一致的预测准确性(无剂量)(平均精度为89%vs. 81%; P = 0.0072)。改进的性能表明,将放射线学方法扩展到荧光分子成像数据为荧光引导手术中的癌症检测提供了有希望的图像分析技术。
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考虑到整个时间领域的信息有助于改善自动驾驶中的环境感知。但是,到目前为止,尚未研究暂时融合的神经网络是否容易受到故意产生的扰动,即对抗性攻击,或者时间历史是否是对它们的固有防御。在这项工作中,我们研究了用于对象检测的时间特征网络是否容易受到通用对抗性攻击的影响。我们评估了两种类型的攻击:整个图像和本地界面贴片的不可察觉噪声。在这两种情况下,使用PGD以白盒方式生成扰动。我们的实验证实,即使攻击时间的一部分时间都足以欺骗网络。我们在视觉上评估生成的扰动,以了解攻击功能。为了增强鲁棒性,我们使用5-PGD应用对抗训练。我们在Kitti和Nuscenes数据集上进行的实验证明了通过K-PGD鲁棒化的模型能够承受研究的攻击,同时保持基于地图的性能与未破坏模型的攻击。
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