Well-annotated medical datasets enable deep neural networks (DNNs) to gain strong power in extracting lesion-related features. Building such large and well-designed medical datasets is costly due to the need for high-level expertise. Model pre-training based on ImageNet is a common practice to gain better generalization when the data amount is limited. However, it suffers from the domain gap between natural and medical images. In this work, we pre-train DNNs on ultrasound (US) domains instead of ImageNet to reduce the domain gap in medical US applications. To learn US image representations based on unlabeled US videos, we propose a novel meta-learning-based contrastive learning method, namely Meta Ultrasound Contrastive Learning (Meta-USCL). To tackle the key challenge of obtaining semantically consistent sample pairs for contrastive learning, we present a positive pair generation module along with an automatic sample weighting module based on meta-learning. Experimental results on multiple computer-aided diagnosis (CAD) problems, including pneumonia detection, breast cancer classification, and breast tumor segmentation, show that the proposed self-supervised method reaches state-of-the-art (SOTA). The codes are available at https://github.com/Schuture/Meta-USCL.
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Deep transfer learning (DTL) has formed a long-term quest toward enabling deep neural networks (DNNs) to reuse historical experiences as efficiently as humans. This ability is named knowledge transferability. A commonly used paradigm for DTL is firstly learning general knowledge (pre-training) and then reusing (fine-tuning) them for a specific target task. There are two consensuses of transferability of pre-trained DNNs: (1) a larger domain gap between pre-training and downstream data brings lower transferability; (2) the transferability gradually decreases from lower layers (near input) to higher layers (near output). However, these consensuses were basically drawn from the experiments based on natural images, which limits their scope of application. This work aims to study and complement them from a broader perspective by proposing a method to measure the transferability of pre-trained DNN parameters. Our experiments on twelve diverse image classification datasets get similar conclusions to the previous consensuses. More importantly, two new findings are presented, i.e., (1) in addition to the domain gap, a larger data amount and huge dataset diversity of downstream target task also prohibit the transferability; (2) although the lower layers learn basic image features, they are usually not the most transferable layers due to their domain sensitivity.
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Understanding of the pathophysiology of obstructive lung disease (OLD) is limited by available methods to examine the relationship between multi-omic molecular phenomena and clinical outcomes. Integrative factorization methods for multi-omic data can reveal latent patterns of variation describing important biological signal. However, most methods do not provide a framework for inference on the estimated factorization, simultaneously predict important disease phenotypes or clinical outcomes, nor accommodate multiple imputation. To address these gaps, we propose Bayesian Simultaneous Factorization (BSF). We use conjugate normal priors and show that the posterior mode of this model can be estimated by solving a structured nuclear norm-penalized objective that also achieves rank selection and motivates the choice of hyperparameters. We then extend BSF to simultaneously predict a continuous or binary response, termed Bayesian Simultaneous Factorization and Prediction (BSFP). BSF and BSFP accommodate concurrent imputation and full posterior inference for missing data, including "blockwise" missingness, and BSFP offers prediction of unobserved outcomes. We show via simulation that BSFP is competitive in recovering latent variation structure, as well as the importance of propagating uncertainty from the estimated factorization to prediction. We also study the imputation performance of BSF via simulation under missing-at-random and missing-not-at-random assumptions. Lastly, we use BSFP to predict lung function based on the bronchoalveolar lavage metabolome and proteome from a study of HIV-associated OLD. Our analysis reveals a distinct cluster of patients with OLD driven by shared metabolomic and proteomic expression patterns, as well as multi-omic patterns related to lung function decline. Software is freely available at https://github.com/sarahsamorodnitsky/BSFP .
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Diffusion models have quickly become the go-to paradigm for generative modelling of perceptual signals (such as images and sound) through iterative refinement. Their success hinges on the fact that the underlying physical phenomena are continuous. For inherently discrete and categorical data such as language, various diffusion-inspired alternatives have been proposed. However, the continuous nature of diffusion models conveys many benefits, and in this work we endeavour to preserve it. We propose CDCD, a framework for modelling categorical data with diffusion models that are continuous both in time and input space. We demonstrate its efficacy on several language modelling tasks.
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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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个性化联合学习(PFL)是一种新的联邦学习(FL)方法,可解决分布式用户设备(UES)生成的数据集的异质性问题。但是,大多数现有的PFL实现都依赖于同步培训来确保良好的收敛性能,这可能会导致严重的散乱问题,在这种情况下,训练时间大量延长了最慢的UE。为了解决这个问题,我们提出了一种半同步PFL算法,被称为半同步个性化的FederatedAveraging(Perfeds $^2 $),而不是移动边缘网络。通过共同优化无线带宽分配和UE调度策略,它不仅减轻了Straggler问题,而且还提供了收敛的培训损失保证。我们根据每回合的参与者数量和回合数量来得出Perfeds2收敛速率的上限。在此基础上,可以使用分析解决方案解决带宽分配问题,并且可以通过贪婪算法获得UE调度策略。实验结果与同步和异步PFL算法相比,验证了Perfeds2在节省训练时间和保证训练损失的收敛方面的有效性。
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我们介绍了第一个机器学习引力波搜索模拟数据挑战(MLGWSC-1)的结果。在这一挑战中,参与的小组必须从二进制黑洞合并中识别出复杂性和持续时间逐渐嵌入在逐渐更现实的噪声中的引力波信号。 4个提供的数据集中的决赛包含O3A观察的真实噪声,并发出了20秒的持续时间,其中包含进动效应和高阶模式。我们介绍了在提交前从参与者未知的1个月的测试数据中得出的6个输入算法的平均灵敏度距离和运行时。其中4个是机器学习算法。我们发现,最好的基于机器学习的算法能够以每月1个的错误警报率(FAR)的速度(FAR)实现基于匹配过滤的生产分析的敏感距离的95%。相反,对于真实的噪音,领先的机器学习搜索获得了70%。为了更高的范围,敏感距离缩小的差异缩小到某些数据集上选择机器学习提交的范围$ \ geq 200 $以优于传统搜索算法的程度。我们的结果表明,当前的机器学习搜索算法可能已经在有限的参数区域中对某些生产设置有用。为了改善最新的技术,机器学习算法需要降低他们能够检测信号并将其有效性扩展到参数空间区域的虚假警报率,在这些区域中,建模的搜索在计算上很昂贵。根据我们的发现,我们汇编了我们认为,将机器学习搜索提升到重力波信号检测中的宝贵工具,我们认为这是最重要的研究领域。
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我们提出了一个数据收集和注释管道,该数据从越南放射学报告中提取信息,以提供胸部X射线(CXR)图像的准确标签。这可以通过注释与其特有诊断类别的数据相匹配,这些数据可能因国家而异。为了评估所提出的标签技术的功效,我们构建了一个包含9,752项研究的CXR数据集,并使用该数据集的子集评估了我们的管道。以F1得分为至少0.9923,评估表明,我们的标签工具在所有类别中都精确而始终如一。构建数据集后,我们训练深度学习模型,以利用从大型公共CXR数据集传输的知识。我们采用各种损失功能来克服不平衡的多标签数据集的诅咒,并使用各种模型体系结构进行实验,以选择提供最佳性能的诅咒。我们的最佳模型(CHEXPERT-FRECTER EDIDENENET-B2)的F1得分为0.6989(95%CI 0.6740,0.7240),AUC为0.7912,敏感性为0.7064,特异性为0.8760,普遍诊断为0.8760。最后,我们证明了我们的粗分类(基于五个特定的异常位置)在基准CHEXPERT数据集上获得了可比的结果(十二个病理),以进行一般异常检测,同时在所有类别的平均表现方面提供更好的性能。
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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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无人驾驶汽车(UAV)在许多领域都受雇于摄影,紧急,娱乐,国防,农业,林业,采矿和建筑。在过去的十年中,无人机技术在许多施工项目阶段中找到了应用程序,从现场映射,进度监控,建筑物检查,损坏评估和材料交付等等。尽管已经对无人机在各种施工相关的过程中的优势进行了广泛的研究,但关于提高任务能力和效率的无人机协作的研究仍然很少。本文提出了一种基于塔格狩猎游戏和粒子群优化(PSO)的多个无人机的新合作路径计划算法。首先,定义了每个无人机的成本函数,并包含多个目标和约束。然后,开发了无人机游戏框架,以将多功能路径计划制定到寻找回报优势均衡的问题。接下来,提出了基于PSO的算法来获得无人机的最佳路径。由三个无人机检查的大型建筑工地的仿真结果表明,在检查任务期间,提出的算法在为无人机形成的可行和高效飞行路径生成可行,高效的飞行路径上的有效性。
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