The instrumental variable (IV) approach is a widely used way to estimate the causal effects of a treatment on an outcome of interest from observational data with latent confounders. A standard IV is expected to be related to the treatment variable and independent of all other variables in the system. However, it is challenging to search for a standard IV from data directly due to the strict conditions. The conditional IV (CIV) method has been proposed to allow a variable to be an instrument conditioning on a set of variables, allowing a wider choice of possible IVs and enabling broader practical applications of the IV approach. Nevertheless, there is not a data-driven method to discover a CIV and its conditioning set directly from data. To fill this gap, in this paper, we propose to learn the representations of the information of a CIV and its conditioning set from data with latent confounders for average causal effect estimation. By taking advantage of deep generative models, we develop a novel data-driven approach for simultaneously learning the representation of a CIV from measured variables and generating the representation of its conditioning set given measured variables. Extensive experiments on synthetic and real-world datasets show that our method outperforms the existing IV methods.
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在科学研究和现实世界应用的许多领域中,非实验数据的因果效应的无偏估计对于理解数据的基础机制以及对有效响应或干预措施的决策至关重要。从不同角度对这个具有挑战性的问题进行了大量研究。对于数据中的因果效应估计,始终做出诸如马尔可夫财产,忠诚和因果关系之类的假设。在假设下,仍然需要一组协变量或基本因果图之类的全部知识。一个实用的挑战是,在许多应用程序中,没有这样的全部知识或只有某些部分知识。近年来,研究已经出现了基于图形因果模型的搜索策略,以从数据中发现有用的知识,以进行因果效应估计,并具有一些温和的假设,并在应对实际挑战方面表现出了诺言。在这项调查中,我们回顾了方法,并关注数据驱动方法所面临的挑战。我们讨论数据驱动方法的假设,优势和局限性。我们希望这篇综述将激励更多的研究人员根据图形因果建模设计更好的数据驱动方法,以解决因果效应估计的具有挑战性的问题。
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本文研究了通过机器学习模型估计特征对特定实例预测的贡献的问题,以及功能对模型的总体贡献。特征(变量)对预测结果的因果效应反映了该特征对预测的贡献。一个挑战是,如果没有已知的因果图,就无法从数据中估算大多数现有的因果效应。在本文中,我们根据假设的理想实验定义了解释性因果效应。该定义给不可知论的解释带来了一些好处。首先,解释是透明的,具有因果关系。其次,解释性因果效应估计可以数据驱动。第三,因果效应既提供了特定预测的局部解释,又提供了一个全局解释,显示了一个特征在预测模型中的总体重要性。我们进一步提出了一种基于解释性因果效应来解释的方法和组合变量的方法。我们显示了对某些现实世界数据集的实验的定义和方法。
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不观察到的混淆是观测数据的因果效应估计的主要障碍。仪器变量(IVS)广泛用于存在潜在混淆时的因果效应估计。利用标准IV方法,当给定的IV有效时,可以获得无偏估计,但标准IV的有效性要求是严格和不可能的。已经提出了通过调节一组观察变量(称为条件IV的调节装置)来放松标准IV的要求。然而,用于查找条件IV的调节集的标准需要完整的因果结构知识或指向的非循环图(DAG),其代表观察到和未观察的变量的因果关系。这使得无法发现直接从数据设置的调节。在本文中,通过利用潜在变量的因果推断中的最大祖先图(MAGS),我们提出了一种新型的MAG中的IV,祖先IV,并开发了支持给定祖传的调节装置的数据驱动的发现iv在mag。基于该理论,我们在MAG和观测数据中开发了一种与祖先IV的非偏见因果效应估计的算法。与现有IV方法相比,对合成和实际数据集的广泛实验表明了算法的性能。
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在个性化决策中,需要证据来确定诉讼(治疗)是否适合个人。可以通过对亚组中的治疗效应异质性进行建模来获得此类证据。现有的可解释的建模方法采用自上而下的方法来寻找具有异质治疗效果的亚组,它们可能会错过个人最具体和最相关的环境。在本文中,我们设计了\ emph {治疗效果模式(TEP)}来表示数据中的治疗效果异质性。为了实现TEP的可解释呈现,我们使用围绕结果的局部因果结构,以明确说明如何在建模中使用这些重要变量。我们还得出了一个公正估计\ emph {条件平均因果效应(CATE)}的公式,它使用我们的问题设置中的局部结构进行了估计。在发现过程中,我们旨在最大程度地减少以模式表示的每个子组中的异质性。我们提出了一种自下而上的搜索算法,以发现适合个性化决策的最具体情况的最特定模式。实验表明,所提出的方法模型治疗效果的异质性比合成和现实世界数据集中的其他三种基于树的方法更好。
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Diabetic Retinopathy (DR) is a leading cause of vision loss in the world, and early DR detection is necessary to prevent vision loss and support an appropriate treatment. In this work, we leverage interactive machine learning and introduce a joint learning framework, termed DRG-Net, to effectively learn both disease grading and multi-lesion segmentation. Our DRG-Net consists of two modules: (i) DRG-AI-System to classify DR Grading, localize lesion areas, and provide visual explanations; (ii) DRG-Expert-Interaction to receive feedback from user-expert and improve the DRG-AI-System. To deal with sparse data, we utilize transfer learning mechanisms to extract invariant feature representations by using Wasserstein distance and adversarial learning-based entropy minimization. Besides, we propose a novel attention strategy at both low- and high-level features to automatically select the most significant lesion information and provide explainable properties. In terms of human interaction, we further develop DRG-Net as a tool that enables expert users to correct the system's predictions, which may then be used to update the system as a whole. Moreover, thanks to the attention mechanism and loss functions constraint between lesion features and classification features, our approach can be robust given a certain level of noise in the feedback of users. We have benchmarked DRG-Net on the two largest DR datasets, i.e., IDRID and FGADR, and compared it to various state-of-the-art deep learning networks. In addition to outperforming other SOTA approaches, DRG-Net is effectively updated using user feedback, even in a weakly-supervised manner.
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Air pollution is an emerging problem that needs to be solved especially in developed and developing countries. In Vietnam, air pollution is also a concerning issue in big cities such as Hanoi and Ho Chi Minh cities where air pollution comes mostly from vehicles such as cars and motorbikes. In order to tackle the problem, the paper focuses on developing a solution that can estimate the emitted PM2.5 pollutants by counting the number of vehicles in the traffic. We first investigated among the recent object detection models and developed our own traffic surveillance system. The observed traffic density showed a similar trend to the measured PM2.5 with a certain lagging in time, suggesting a relation between traffic density and PM2.5. We further express this relationship with a mathematical model which can estimate the PM2.5 value based on the observed traffic density. The estimated result showed a great correlation with the measured PM2.5 plots in the urban area context.
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Pareto Front Learning (PFL) was recently introduced as an effective approach to obtain a mapping function from a given trade-off vector to a solution on the Pareto front, which solves the multi-objective optimization (MOO) problem. Due to the inherent trade-off between conflicting objectives, PFL offers a flexible approach in many scenarios in which the decision makers can not specify the preference of one Pareto solution over another, and must switch between them depending on the situation. However, existing PFL methods ignore the relationship between the solutions during the optimization process, which hinders the quality of the obtained front. To overcome this issue, we propose a novel PFL framework namely \ourmodel, which employs a hypernetwork to generate multiple solutions from a set of diverse trade-off preferences and enhance the quality of the Pareto front by maximizing the Hypervolume indicator defined by these solutions. The experimental results on several MOO machine learning tasks show that the proposed framework significantly outperforms the baselines in producing the trade-off Pareto front.
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多分辨率的深度学习方法,例如U-NET体系结构,在分类和分割图像中已经达到了高性能。但是,这些方法不能提供潜在的图像表示形式,也不能用于分解,denoise和重建图像数据。 U-NET和其他卷积神经网络(CNNS)通常使用合并来扩大接受场,这通常会导致不可逆的信息丢失。这项研究建议包括riesz-quincunx(RQ)小波变换,结合1)高阶Riesz小波变换和2)在U-NET体系结构内正交Quincunx小波(两者都用于减少医学图像中的模糊) ,以减少卫星图像及其时间序列中的噪音。在变换的特征空间中,我们提出了一种变异方法,以了解特征的随机扰动如何影响图像以进一步降低噪声。结合两种方法,我们引入了一种用于减少卫星图像中噪声的图像和时间序列分解的混合Rqunet-VAE方案。我们提出了定性和定量的实验结果,表明与其他最先进的方法相比,我们提出的Rqunet-VAE在降低卫星图像中的噪声方面更有效。我们还将我们的方案应用于多波段卫星图像的多个应用程序,包括:通过扩散和图像分割分解图像denoising,图像和时间序列分解。
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鉴于在各种条件和背景下捕获的图像的识别药物已经变得越来越重要。已经致力于利用基于深度学习的方法来解决文献中的药丸识别问题。但是,由于药丸的外观之间的相似性很高,因此经常发生错误识别,因此识别药丸是一个挑战。为此,在本文中,我们介绍了一种名为Pika的新颖方法,该方法利用外部知识来增强药丸识别精度。具体来说,我们解决了一种实用的情况(我们称之为上下文药丸识别),旨在在患者药丸摄入量的情况下识别药丸。首先,我们提出了一种新的方法,用于建模在存在外部数据源的情况下,在这种情况下,在存在外部处方的情况下,药丸之间的隐式关联。其次,我们提出了一个基于步行的图形嵌入模型,该模型从图形空间转换为矢量空间,并提取药丸的凝结关系。第三,提供了最终框架,该框架利用基于图像的视觉和基于图的关系特征来完成药丸识别任务。在此框架内,每种药丸的视觉表示形式都映射到图形嵌入空间,然后用来通过图表执行注意力,从而产生了有助于最终分类的语义丰富的上下文矢量。据我们所知,这是第一项使用外部处方数据来建立药物之间的关联并使用此帮助信息对其进行分类的研究。皮卡(Pika)的体系结构轻巧,并且具有将识别骨架纳入任何识别骨架的灵活性。实验结果表明,通过利用外部知识图,与基线相比,PIKA可以将识别精度从4.8%提高到34.1%。
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