在极端分辨率上监测植被生产力对于现实世界中的农业应用非常有价值,例如检测作物压力和提供粮食不安全的预警。太阳能诱导的叶绿素荧光(SIF)提供了一种直接从空间中测量植物生产力的有希望的方法。但是,卫星SIF观察只能以粗空间分辨率进行,因此无法监视单个农作物类型或农场的表现。这构成了一个具有挑战性的粗略监督回归(或缩小)任务;在训练时,我们只有粗分辨率(3公里)的SIF标签,但我们希望以更精细的空间分辨率预测SIF(例如30m,增加了100倍)。我们还具有其他精细分辨率输入功能,但是这些功能与SIF之间的关系尚不清楚。为了解决这个问题,我们提出了一种粗糙的平滑U-NET(CS-Sunet),这是这种粗糙监督设置的新方法。 CS-Sunet基于先验知识(例如平滑度损失),将深卷卷网络的表达能力与新颖的正则化方法相结合,这对于防止过度拟合至关重要。实验表明,CS-Sunet比现有方法更准确地解决SIF中的细粒变化。
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气候变化对作物相关的疑虑构成了新的挑战,包括粮食不安全,供应稳定和经济规划。作为中央挑战之一,作物产量预测已成为机器学习领域的按压任务。尽管重要的是,预测任务是特别的复杂性,因为作物产量取决于天气,陆地,土壤质量等各种因素,以及它们的相互作用。近年来,在该域中成功应用了机器学习模型。然而,这些模型要么将他们的任务限制为相对较小的区域,或者只在单个或几年内进行研究,这使得它们难以在空间和时间上概括。在本文中,我们介绍了一种用于作物产量预测的新型图形的复发性神经网络,以纳入模型中的地理和时间知识,进一步提升预测力。我们的方法是在美国大陆的41个州的2000年历史上进行培训,验证和测试,从1981年到2019年覆盖了几年。据我们所知,这是第一种机器学习方法,可在作物产量预测中嵌入地理知识预测全国县级的作物产量。我们还通过应用众所周知的线性模型,基于树的模型,深度学习方法以及比较它们的性能来对与其他机器学习基线进行稳固的基础。实验表明,我们的提出方法始终如一地优于各种指标上现有的现有方法,验证地理空间和时间信息的有效性。
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尽管当前的视觉算法在许多具有挑战性的任务上都表现出色,但尚不清楚他们如何理解现实世界环境的物理动态。在这里,我们介绍了Physion,一种数据集和基准,用于严格评估预测物理场景如何随着时间而发展的能力。我们的数据集具有对各种物理现象的现实模拟,包括刚性和软体体碰撞,稳定的多对象配置,滚动,滑动和弹丸运动,因此比以前的基准提供了更全面的挑战。我们使用Physion来基准一套模型,其体系结构,学习目标,投入输出结构和培训数据各不相同。同时,我们在同一场景上获得了人类预测行为的精确测量,从而使我们能够直接评估任何模型能够近似人类行为的效果。我们发现,学习以对象为中心的表示的视觉算法通常优于那些没有人的表现,但仍未达到人类绩效。另一方面,绘制具有直接访问物理状态信息的神经网络的表现效果更好,并且做出与人类制作的预测更相似。这些结果表明,提取场景的物理表征是在视力算法中实现人类水平和类似人类的物理理解的主要瓶颈。我们已公开发布了所有数据和代码,以促进使用物理以完全可重现的方式对其他模型进行基准测试,从而使对视觉算法的进度进行系统的评估,这些算法像人们一样坚固地了解物理环境。
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Understanding the relationship between structure and sentiment is essential in highlighting future operations with online social networks. More specifically, within popular conversation on Twitter. This paper provides a development on the relationship between the two variables: structure, defined as the composition of a directed network, and sentiment, a quantified value of the positive/negative connotations of a conversation. We highlight thread sentiment to be inversely proportional to the strength and connectivity of a network. The second portion of this paper highlights differences in query types, specifically how the aforementioned behavior differs within four key query types. This paper focuses on topical, event-based, geographic, and individual queries as orientations which have differing behavior. Using cross-query analysis, we see that the relationship between structure and sentiment, though still inversely proportional, differs greatly across query types. We find this relationship to be the most clear within the individual queries and the least prevalent within the event-based queries. This paper provides a sociological progression in our understanding of opinion and networks, while providing a methodological advancement for future studies on similar subjects.
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We present temporally layered architecture (TLA), a biologically inspired system for temporally adaptive distributed control. TLA layers a fast and a slow controller together to achieve temporal abstraction that allows each layer to focus on a different time-scale. Our design is biologically inspired and draws on the architecture of the human brain which executes actions at different timescales depending on the environment's demands. Such distributed control design is widespread across biological systems because it increases survivability and accuracy in certain and uncertain environments. We demonstrate that TLA can provide many advantages over existing approaches, including persistent exploration, adaptive control, explainable temporal behavior, compute efficiency and distributed control. We present two different algorithms for training TLA: (a) Closed-loop control, where the fast controller is trained over a pre-trained slow controller, allowing better exploration for the fast controller and closed-loop control where the fast controller decides whether to "act-or-not" at each timestep; and (b) Partially open loop control, where the slow controller is trained over a pre-trained fast controller, allowing for open loop-control where the slow controller picks a temporally extended action or defers the next n-actions to the fast controller. We evaluated our method on a suite of continuous control tasks and demonstrate the advantages of TLA over several strong baselines.
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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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We present a new algorithm for automatically bounding the Taylor remainder series. In the special case of a scalar function $f: \mathbb{R} \mapsto \mathbb{R}$, our algorithm takes as input a reference point $x_0$, trust region $[a, b]$, and integer $k \ge 0$, and returns an interval $I$ such that $f(x) - \sum_{i=0}^k \frac {f^{(i)}(x_0)} {i!} (x - x_0)^i \in I (x - x_0)^{k+1}$ for all $x \in [a, b]$. As in automatic differentiation, the function $f$ is provided to the algorithm in symbolic form, and must be composed of known elementary functions. At a high level, our algorithm has two steps. First, for a variety of commonly-used elementary functions (e.g., $\exp$, $\log$), we derive sharp polynomial upper and lower bounds on the Taylor remainder series. We then recursively combine the bounds for the elementary functions using an interval arithmetic variant of Taylor-mode automatic differentiation. Our algorithm can make efficient use of machine learning hardware accelerators, and we provide an open source implementation in JAX. We then turn our attention to applications. Most notably, we use our new machinery to create the first universal majorization-minimization optimization algorithms: algorithms that iteratively minimize an arbitrary loss using a majorizer that is derived automatically, rather than by hand. Applied to machine learning, this leads to architecture-specific optimizers for training deep networks that converge from any starting point, without hyperparameter tuning. Our experiments show that for some optimization problems, these hyperparameter-free optimizers outperform tuned versions of gradient descent, Adam, and AdaGrad. We also show that our automatically-derived bounds can be used for verified global optimization and numerical integration, and to prove sharper versions of Jensen's inequality.
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A typical product or place often has hundreds of reviews, and summarization of these texts is an important and challenging problem. Recent progress on abstractive summarization in domains such as news has been driven by supervised systems trained on hundreds of thousands of news articles paired with human-written summaries. However for opinion texts, such large scale datasets are rarely available. Unsupervised methods, self-training, and few-shot learning approaches bridge that gap. In this work, we present a novel self-training approach, OpineSum, for abstractive opinion summarization. The summaries in this approach are built using a novel application of textual entailment and capture the consensus of opinions across the various reviews for an item. This method can be used to obtain silver-standard summaries on a large scale and train both unsupervised and few-shot abstractive summarization systems. OpineSum achieves state-of-the-art performance in both settings.
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The applicability of computational models to the biological world is an active topic of debate. We argue that a useful path forward results from abandoning hard boundaries between categories and adopting an observer-dependent, pragmatic view. Such a view dissolves the contingent dichotomies driven by human cognitive biases (e.g., tendency to oversimplify) and prior technological limitations in favor of a more continuous, gradualist view necessitated by the study of evolution, developmental biology, and intelligent machines. Efforts to re-shape living systems for biomedical or bioengineering purposes require prediction and control of their function at multiple scales. This is challenging for many reasons, one of which is that living systems perform multiple functions in the same place at the same time. We refer to this as "polycomputing" - the ability of the same substrate to simultaneously compute different things. This ability is an important way in which living things are a kind of computer, but not the familiar, linear, deterministic kind; rather, living things are computers in the broad sense of computational materials as reported in the rapidly-growing physical computing literature. We argue that an observer-centered framework for the computations performed by evolved and designed systems will improve the understanding of meso-scale events, as it has already done at quantum and relativistic scales. Here, we review examples of biological and technological polycomputing, and develop the idea that overloading of different functions on the same hardware is an important design principle that helps understand and build both evolved and designed systems. Learning to hack existing polycomputing substrates, as well as evolve and design new ones, will have massive impacts on regenerative medicine, robotics, and computer engineering.
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Abstractive summarization has enjoyed renewed interest in recent years, thanks to pre-trained language models and the availability of large-scale datasets. Despite promising results, current models still suffer from generating factually inconsistent summaries, reducing their utility for real-world application. Several recent efforts attempt to address this by devising models that automatically detect factual inconsistencies in machine generated summaries. However, they focus exclusively on English, a language with abundant resources. In this work, we leverage factual consistency evaluation models to improve multilingual summarization. We explore two intuitive approaches to mitigate hallucinations based on the signal provided by a multilingual NLI model, namely data filtering and controlled generation. Experimental results in the 45 languages from the XLSum dataset show gains over strong baselines in both automatic and human evaluation.
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