放射造影通常用于探测动态系统中的复杂,不断发展的密度字段,以便在潜在的物理学中实现进入洞察力。该技术已用于许多领域,包括材料科学,休克物理,惯性监禁融合和其他国家安全应用。然而,在许多这些应用中,噪声,散射,复杂光束动力学等的并发症防止了密度的重建足以足以识别具有足够置信度的底层物理。因此,来自静态/动态射线照相的密度重建通常限于在许多这些应用中识别诸如裂缝和空隙的不连续特征。在这项工作中,我们提出了一种从基本上重建密度的基本上新的射线照片序列的密度。仅使用射线照相识别的稳健特征,我们将它们与使用机器学习方法的底层流体动力方程组合,即条件生成对冲网络(CGAN),以从射线照片的动态序列确定密度字段。接下来,我们寻求通过参数估计和投影的过程进一步提高ML的密度重建的流体动力学一致性,并进入流体动力歧管。在这种情况下,我们注意到,训练数据给出的流体动力歧管在被认为的参数空间中给出的测试数据是用于预测的稳定性的诊断,并用于增强培训数据库,期望后者将进一步降低未来的密度重建错误。最后,我们展示了这种方法优于传统的射线照相重建在捕获允许的流体动力学路径中的能力,即使存在相对少量的散射。
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Data deprivation, or the lack of easily available and actionable information on the well-being of individuals, is a significant challenge for the developing world and an impediment to the design and operationalization of policies intended to alleviate poverty. In this paper we explore the suitability of data derived from OpenStreetMap to proxy for the location of two crucial public services: schools and health clinics. Thanks to the efforts of thousands of digital humanitarians, online mapping repositories such as OpenStreetMap contain millions of records on buildings and other structures, delineating both their location and often their use. Unfortunately much of this data is locked in complex, unstructured text rendering it seemingly unsuitable for classifying schools or clinics. We apply a scalable, unsupervised learning method to unlabeled OpenStreetMap building data to extract the location of schools and health clinics in ten countries in Africa. We find the topic modeling approach greatly improves performance versus reliance on structured keys alone. We validate our results by comparing schools and clinics identified by our OSM method versus those identified by the WHO, and describe OSM coverage gaps more broadly.
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Governments, industry, and academia have undertaken efforts to identify and mitigate harms in ML-driven systems, with a particular focus on social and ethical risks of ML components in complex sociotechnical systems. However, existing approaches are largely disjointed, ad-hoc and of unknown effectiveness. Systems safety engineering is a well established discipline with a track record of identifying and managing risks in many complex sociotechnical domains. We adopt the natural hypothesis that tools from this domain could serve to enhance risk analyses of ML in its context of use. To test this hypothesis, we apply a "best of breed" systems safety analysis, Systems Theoretic Process Analysis (STPA), to a specific high-consequence system with an important ML-driven component, namely the Prescription Drug Monitoring Programs (PDMPs) operated by many US States, several of which rely on an ML-derived risk score. We focus in particular on how this analysis can extend to identifying social and ethical risks and developing concrete design-level controls to mitigate them.
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本文介绍了一种在同时定位和映射(SLAM)框架中进行可靠测量的方法。现有方法在成对的基础上检查一致性或兼容性,但是在成对场景中,许多测量类型都没有足够的约束,以确定是否与其他测量不一致。本文介绍了组-K $一致性最大化(G $ K $ cm),该估计最大的测量值是内部组的一致性。可以为最大的组$ k $一致测量的求解作为广义图上最大集团问题的实例,并可以通过调整电流方法来解决。本文使用模拟数据评估了G $ K $ CM的性能,并将其与以前工作中介绍的成对一致性最大化(PCM)进行比较。
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语言模型既展示了定量的改进,又展示了新的定性功能,随着规模的增加。尽管它们具有潜在的变革性影响,但这些新能力的特征却很差。为了为未来的研究提供信息,为破坏性的新模型能力做准备,并改善社会有害的效果,至关重要的是,我们必须了解目前和近乎未来的能力和语言模型的局限性。为了应对这一挑战,我们介绍了超越模仿游戏基准(Big Bench)。 Big Bench目前由204个任务组成,由132家机构的442位作者贡献。任务主题是多样的,从语言学,儿童发展,数学,常识性推理,生物学,物理学,社会偏见,软件开发等等。 Big-Bench专注于被认为超出当前语言模型的功能的任务。我们评估了OpenAI的GPT型号,Google内部密集变压器体系结构和大型基础上的开关稀疏变压器的行为,跨越了数百万到数十亿个参数。此外,一个人类专家评估者团队执行了所有任务,以提供强大的基准。研究结果包括:模型性能和校准都随规模改善,但绝对的术语(以及与评估者的性能相比);在模型类中的性能非常相似,尽管带有稀疏性。逐渐和预测的任务通常涉及大量知识或记忆成分,而在临界规模上表现出“突破性”行为的任务通常涉及多个步骤或组成部分或脆性指标;社交偏见通常会随着含糊不清的环境而随着规模而增加,但这可以通过提示来改善。
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如果对准确的预测的置信度不足,则选择性回归允许弃权。通常,通过允许拒绝选项,人们期望回归模型的性能会以减少覆盖范围的成本(即预测较少的样本)的成本提高。但是,正如我们所显示的,在某些情况下,少数子组的性能可以减少,同时我们减少覆盖范围,因此选择性回归可以放大不同敏感亚组之间的差异。在这些差异的推动下,我们提出了新的公平标准,用于选择性回归,要求每个子组的性能在覆盖范围内降低。我们证明,如果特征表示满足充分性标准或为均值和方差进行校准,则与所提出的公平标准相比。此外,我们介绍了两种方法,以减轻子组之间的性能差异:(a)通过在高斯假设下正规化有条件相互信息的上限,以及(b)通过对条件均值和条件方差预测的对比度损失正规。这些方法的有效性已在合成和现实世界数据集上证明。
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Amoebot模型将主动的可编程物质抽象为简单的计算元素的集合,称为Amoebot,它们在本地交互以集体完成协调和运动任务。自2014年SPAA推出以来,越来越多的文献已经改编了其对各种问题的假设。但是,如果没有标准化的假设层次结构,则很难对Amoebot模型下的结果进行精确的系统比较。我们提出了规范的Amoebot模型,该模型是一个更新的形式化,可区分核心模型特征和假设变体系列。规范Amoebot模型解决的关键改进是并发。现有的许多文献隐含地假设Amoebot动作是孤立且可靠的,将分析降低到一个顺序设置,其中最多一次是Amoebot活跃的。但是,实际可编程系统是并发的。 Canonical Amoebot模型将所有Amoebot通信形式化为消息传递,利用并发执行的对抗激活模型。在这种颗粒状的时间处理下,我们采用两种互补方法来并发算法设计。我们首先在任何并发执行下建立一组足够的条件,以实现算法正确性,将并发控制直接嵌入算法设计中。然后,我们提出了一个并发控制框架,该框架使用锁来转换在顺序设置中终止的Amoebot算法,并满足某些约定在并发设置中表现出等效行为的算法中的某些约定。作为案例研究,我们使用简单的六边形形成算法证明了这两种方法。共同的Amoebot模型以及这些并发算法设计的互补方法设计开放的新方向,用于分布式计算可编程问题。
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学习排名 - 制作特定于查询的项目的排名列表以及一组监督项目 - 是一个普遍兴趣的问题。我们认为的设置是没有分析描述构成良好排名的设置。取而代之的是,我们有一个包含(目标项目,有趣的项目集)对的表示和监督信息的集合。我们在仿真中进行了分析证明,在实际数据示例中,当监督与“这几个相似的项目相似”时,通过使用整数线性程序组合表示来进行排名是有效的。尽管这项提名任务是相当普遍的,但对于特异性,我们从图表中的顶点提名的角度介绍了我们的方法论。本文描述的方法是模型不可知论。
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Making histopathology image classifiers robust to a wide range of real-world variability is a challenging task. Here, we describe a candidate deep learning solution for the Mitosis Domain Generalization Challenge 2022 (MIDOG) to address the problem of generalization for mitosis detection in images of hematoxylin-eosin-stained histology slides under high variability (scanner, tissue type and species variability). Our approach consists in training a rotation-invariant deep learning model using aggressive data augmentation with a training set enriched with hard negative examples and automatically selected negative examples from the unlabeled part of the challenge dataset. To optimize the performance of our models, we investigated a hard negative mining regime search procedure that lead us to train our best model using a subset of image patches representing 19.6% of our training partition of the challenge dataset. Our candidate model ensemble achieved a F1-score of .697 on the final test set after automated evaluation on the challenge platform, achieving the third best overall score in the MIDOG 2022 Challenge.
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Supervised Question Answering systems (QA systems) rely on domain-specific human-labeled data for training. Unsupervised QA systems generate their own question-answer training pairs, typically using secondary knowledge sources to achieve this outcome. Our approach (called PIE-QG) uses Open Information Extraction (OpenIE) to generate synthetic training questions from paraphrased passages and uses the question-answer pairs as training data for a language model for a state-of-the-art QA system based on BERT. Triples in the form of <subject, predicate, object> are extracted from each passage, and questions are formed with subjects (or objects) and predicates while objects (or subjects) are considered as answers. Experimenting on five extractive QA datasets demonstrates that our technique achieves on-par performance with existing state-of-the-art QA systems with the benefit of being trained on an order of magnitude fewer documents and without any recourse to external reference data sources.
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