大多数现有的因果结构学习方法需要数据以独立且相同分布(i.i.d.),当数据来自不同环境时,通常无法保证。以前的一些努力在两个独立的阶段中尝试解决这个问题,即首次发现i.i.d.非i.i.d的集群。样品,然后学习来自不同组的因果结构。这种直接的解决方案忽略了两个阶段之间的内在连接,即聚类阶段,学习阶段应该被相同的因果机制引导。为此,我们提出了一个统一的因果关系结构学习(命名为CCSL)方法,用于来自非I.I.D的因果区。数据。该方法同时集成了以下两个任务:1)聚类对象具有相同的因果机制; 2)学习受试者样本的因果关系。具体而言,对于前者来说,我们基于因果结构的相似性为集群样本提供了与因果关系相关的中餐馆流程;对于后者,我们介绍了一种基于改性的基于改进的方法来学习因果结构。理论结果提供了线性非高斯假设下因果模型和聚类模型的识别。模拟和现实世界数据的实验结果进一步验证了所提出的方法的正确性和有效性。
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在许多科学领域,观察数据中的因果发现是一项重要但具有挑战性的任务。最近,一种称为宣传的非组合定向无环约束的方法将因果结构学习问题作为使用最小二乘损失的连续优化问题。尽管在标准高斯噪声假设下,最小二乘损耗函数是合理的,但如果假设不存在,则受到限制。在这项工作中,我们从理论上表明,违反高斯噪声假设将阻碍因果方向的识别,从而使因果强度以及线性案例中的噪声和噪声方差完全确定。在非线性情况下的噪音。因此,我们提出了一个更一般的基于熵的损失,理论上与任何噪声分布下的可能性得分一致。我们对合成数据和现实世界数据进行了广泛的经验评估,以验证所提出的方法的有效性,并表明我们的方法在结构锤距离,错误发现率和真实的正速率矩阵方面达到了最佳状态。
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因果推断对于跨业务参与,医疗和政策制定等领域的数据驱动决策至关重要。然而,关于因果发现的研究已经与推理方法分开发展,从而阻止了两个领域方法的直接组合。在这项工作中,我们开发了深层端到端因果推理(DECI),这是一种基于流动的非线性添加噪声模型,该模型具有观察数据,并且可以执行因果发现和推理,包括有条件的平均治疗效果(CATE) )估计。我们提供了理论上的保证,即DECI可以根据标准因果发现假设恢复地面真实因果图。受应用影响的激励,我们将该模型扩展到具有缺失值的异质,混合型数据,从而允许连续和离散的治疗决策。我们的结果表明,与因果发现的相关基线相比,DECI的竞争性能和(c)在合成数据集和因果机器学习基准测试基准的一千多个实验中,跨数据类型和缺失水平进行了估计。
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State-of-the-art causal discovery methods usually assume that the observational data is complete. However, the missing data problem is pervasive in many practical scenarios such as clinical trials, economics, and biology. One straightforward way to address the missing data problem is first to impute the data using off-the-shelf imputation methods and then apply existing causal discovery methods. However, such a two-step method may suffer from suboptimality, as the imputation algorithm may introduce bias for modeling the underlying data distribution. In this paper, we develop a general method, which we call MissDAG, to perform causal discovery from data with incomplete observations. Focusing mainly on the assumptions of ignorable missingness and the identifiable additive noise models (ANMs), MissDAG maximizes the expected likelihood of the visible part of observations under the expectation-maximization (EM) framework. In the E-step, in cases where computing the posterior distributions of parameters in closed-form is not feasible, Monte Carlo EM is leveraged to approximate the likelihood. In the M-step, MissDAG leverages the density transformation to model the noise distributions with simpler and specific formulations by virtue of the ANMs and uses a likelihood-based causal discovery algorithm with directed acyclic graph constraint. We demonstrate the flexibility of MissDAG for incorporating various causal discovery algorithms and its efficacy through extensive simulations and real data experiments.
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因果代表学习揭示了低级观察背后的潜在高级因果变量,这对于一组感兴趣的下游任务具有巨大的潜力。尽管如此,从观察到的数据中确定真正的潜在因果表示是一个巨大的挑战。在这项工作中,我们专注于确定潜在的因果变量。为此,我们分析了潜在空间中的三个固有特性,包括传递性,置换和缩放。我们表明,传递性严重阻碍了潜在因果变量的可识别性,而排列和缩放指导指导了识别潜在因果变量的方向。为了打破传递性,我们假设潜在的潜在因果关系是线性高斯模型,其中高斯噪声的权重,平均值和方差受到额外观察到的变量的调节。在这些假设下,我们从理论上表明,潜在因果变量可以识别为微不足道的置换和缩放。基于这个理论结果,我们提出了一种新型方法,称为结构性因果变异自动编码器,该方法直接学习潜在因果变量,以及从潜在因果变量到观察到的映射。关于合成和实际数据的实验结果证明了可识别的结果以及所提出的学习潜在因果变量的能力。
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Bayesian causal structure learning aims to learn a posterior distribution over directed acyclic graphs (DAGs), and the mechanisms that define the relationship between parent and child variables. By taking a Bayesian approach, it is possible to reason about the uncertainty of the causal model. The notion of modelling the uncertainty over models is particularly crucial for causal structure learning since the model could be unidentifiable when given only a finite amount of observational data. In this paper, we introduce a novel method to jointly learn the structure and mechanisms of the causal model using Variational Bayes, which we call Variational Bayes-DAG-GFlowNet (VBG). We extend the method of Bayesian causal structure learning using GFlowNets to learn not only the posterior distribution over the structure, but also the parameters of a linear-Gaussian model. Our results on simulated data suggest that VBG is competitive against several baselines in modelling the posterior over DAGs and mechanisms, while offering several advantages over existing methods, including the guarantee to sample acyclic graphs, and the flexibility to generalize to non-linear causal mechanisms.
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作为在人类智能中获得可推广的解决方案的关键组成部分,推理为加强学习(RL)代理人对各种目标的概括提供了巨大的潜力,这是通过汇总部分到全部的论点并发现因果关系的。但是,如何发现和代表因果关系仍然是阻碍因果RL发展的巨大差距。在本文中,我们使用因果图(CG)增强目标条件的RL(GCRL),该结构是基于对象和事件之间的关系建立的。我们在小新生中将GCRL问题提出为变异的可能性最大化,将CG作为潜在变量。为了优化派生目标,我们提出了一个具有理论性能的框架,可以保证在两个步骤之间交替:使用介入数据来估计CG的后验;使用CG学习可推广的模型和可解释的政策。由于缺乏在推理下验证概括能力的公共基准测试,我们设计了九个任务,然后从经验上显示了对这些任务上五个基准的拟议方法的有效性。进一步的理论分析表明,我们的绩效提高归因于因果发现,过渡建模和政策培训的良性周期,这与广泛消融研究中的实验证据相吻合。
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Estimating the structure of directed acyclic graphs (DAGs) of features (variables) plays a vital role in revealing the latent data generation process and providing causal insights in various applications. Although there have been many studies on structure learning with various types of data, the structure learning on the dynamic graph has not been explored yet, and thus we study the learning problem of node feature generation mechanism on such ubiquitous dynamic graph data. In a dynamic graph, we propose to simultaneously estimate contemporaneous relationships and time-lagged interaction relationships between the node features. These two kinds of relationships form a DAG, which could effectively characterize the feature generation process in a concise way. To learn such a DAG, we cast the learning problem as a continuous score-based optimization problem, which consists of a differentiable score function to measure the validity of the learned DAGs and a smooth acyclicity constraint to ensure the acyclicity of the learned DAGs. These two components are translated into an unconstraint augmented Lagrangian objective which could be minimized by mature continuous optimization techniques. The resulting algorithm, named GraphNOTEARS, outperforms baselines on simulated data across a wide range of settings that may encounter in real-world applications. We also apply the proposed approach on two dynamic graphs constructed from the real-world Yelp dataset, demonstrating our method could learn the connections between node features, which conforms with the domain knowledge.
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Causal learning has attracted much attention in recent years because causality reveals the essential relationship between things and indicates how the world progresses. However, there are many problems and bottlenecks in traditional causal learning methods, such as high-dimensional unstructured variables, combinatorial optimization problems, unknown intervention, unobserved confounders, selection bias and estimation bias. Deep causal learning, that is, causal learning based on deep neural networks, brings new insights for addressing these problems. While many deep learning-based causal discovery and causal inference methods have been proposed, there is a lack of reviews exploring the internal mechanism of deep learning to improve causal learning. In this article, we comprehensively review how deep learning can contribute to causal learning by addressing conventional challenges from three aspects: representation, discovery, and inference. We point out that deep causal learning is important for the theoretical extension and application expansion of causal science and is also an indispensable part of general artificial intelligence. We conclude the article with a summary of open issues and potential directions for future work.
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因果表示学习是识别基本因果变量及其从高维观察(例如图像)中的关系的任务。最近的工作表明,可以从观测的时间序列中重建因果变量,假设它们之间没有瞬时因果关系。但是,在实际应用中,我们的测量或帧速率可能比许多因果效应要慢。这有效地产生了“瞬时”效果,并使以前的可识别性结果无效。为了解决这个问题,我们提出了ICITRI,这是一种因果表示学习方法,当具有已知干预目标的完美干预措施时,可以在时间序列中处理瞬时效应。 Icitris从时间观察中识别因果因素,同时使用可区分的因果发现方法来学习其因果图。在三个视频数据集的实验中,Icitris准确地识别了因果因素及其因果图。
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我们介绍了一个新型的多层加权网络模型,该模型除了本地信号外,还考虑了全局噪声。该模型类似于多层随机块模型(SBM),但关键区别在于,跨层之间的块之间的相互作用在整个系统中是常见的,我们称之为环境噪声。单个块还以这些固定的环境参数为特征,以表示不属于其他任何地方的成员。这种方法允许将块同时聚类和类型化到信号或噪声中,以便更好地理解其在整个系统中的作用,而现有块模型未考虑。我们采用了分层变异推断的新颖应用来共同检测和区分块类型。我们称此模型为多层加权网络称为随机块(具有)环境噪声模型(SBANM),并开发了相关的社区检测算法。我们将此方法应用于费城神经发育队列中的受试者,以发现与精神病有关的具有共同心理病理学的受试者社区。
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结构方程模型(SEM)是一种有效的框架,其原因是通过定向非循环图(DAG)表示的因果关系。最近的进步使得能够从观察数据中实现了DAG的最大似然点估计。然而,在实际场景中,可以不能准确地捕获在推断下面的底层图中的不确定性,其中真正的DAG是不可识别的并且/或观察到的数据集是有限的。我们提出了贝叶斯因果发现网(BCD网),一个变分推理框架,用于估算表征线性高斯SEM的DAG的分布。由于图形的离散和组合性质,开发一个完整的贝叶斯后面是挑战。我们通过表达变分别家庭分析可扩展VI的可扩展VI的关键设计选择,例如1)表达性变分别家庭,2)连续弛豫,使低方差随机优化和3)在潜在变量上具有合适的前置。我们提供了一系列关于实际和合成数据的实验,显示BCD网在低数据制度中的标准因果发现度量上的最大似然方法,例如结构汉明距离。
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重度抑郁症(MDD)需要研究患者的大脑功能连通性改变,可以通过静止状态功能磁共振成像(RS-FMRI)数据发现。我们考虑确定单个MDD患者大脑功能连通性改变的问题。这是特别困难的,因为在fMRI扫描期间收集的数据量过于限制,无法为个人分析提供足够的信息。此外,RS-FMRI数据通常具有不完整,稀疏性,可变性,高维度和高噪声的特征。为了解决这些问题,我们提出了一个多任务高斯贝叶斯网络(MTGBN)框架,该框架能够识别MDD患者的个体疾病诱导的改变。我们假设这种疾病引起的改变显示了与该工具相似的程度,以学习从观察到了解系统如何共同从相关任务结构构造的网络结构。首先,我们将每类观察中的每个患者视为一项任务,然后通过从共享编码先验知识的默认协方差矩阵的所有任务中学习该数据类的高斯贝叶斯网络(GBN)。此设置可以帮助我们从有限的数据中学习更多信息。接下来,我们得出了完整的似然函数的封闭式公式,并使用蒙特卡洛期望 - 最大化(MCEM)算法有效地搜索大约最佳的贝叶斯网络结构。最后,我们通过模拟和现实世界的RS-FMRI数据评估方法的性能。
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We consider the problem of recovering the causal structure underlying observations from different experimental conditions when the targets of the interventions in each experiment are unknown. We assume a linear structural causal model with additive Gaussian noise and consider interventions that perturb their targets while maintaining the causal relationships in the system. Different models may entail the same distributions, offering competing causal explanations for the given observations. We fully characterize this equivalence class and offer identifiability results, which we use to derive a greedy algorithm called GnIES to recover the equivalence class of the data-generating model without knowledge of the intervention targets. In addition, we develop a novel procedure to generate semi-synthetic data sets with known causal ground truth but distributions closely resembling those of a real data set of choice. We leverage this procedure and evaluate the performance of GnIES on synthetic, real, and semi-synthetic data sets. Despite the strong Gaussian distributional assumption, GnIES is robust to an array of model violations and competitive in recovering the causal structure in small- to large-sample settings. We provide, in the Python packages "gnies" and "sempler", implementations of GnIES and our semi-synthetic data generation procedure.
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了解因果关系有助于构建干预措施,以实现特定的目标并在干预下实现预测。随着学习因果关系的越来越重要,因果发现任务已经从使用传统方法推断出潜在的因果结构从观察数据到深度学习涉及的模式识别领域。大量数据的快速积累促进了具有出色可扩展性的因果搜索方法的出现。因果发现方法的现有摘要主要集中在基于约束,分数和FCM的传统方法上,缺乏针对基于深度学习的方法的完美分类和阐述,还缺乏一些考虑和探索因果关系的角度来探索因果发现方法范式。因此,我们根据变量范式将可能的因果发现任务分为三种类型,并分别给出三个任务的定义,定义和实例化每个任务的相关数据集以及同时构建的最终因果模型,然后审查不同任务的主要因果发现方法。最后,我们从不同角度提出了一些路线图,以解决因果发现领域的当前研究差距,并指出未来的研究方向。
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本文介绍了一种新型的因果结构,即多尺度非平稳的定向无环图(MN-DAG),该图将DAG概括为时频域。我们的贡献是双重的。首先,通过利用光谱和因果关系的结果,我们揭露了一种新型的概率生成模型,该模型允许根据用户指定的先验对因果图的时间依赖性和多尺度属性进行采样。其次,我们通过随机变异推理(SVI)(称为多阶层非稳态的因果结构学习者(MN-Castle))设计了一种用于估计Mn-DAGS的贝叶斯方法。除了直接观察外,MN-Castle还通过不同时间分辨率的时间序列的总功率谱分解来利用信息。在我们的实验中,我们首先使用所提出的模型根据潜在的MN-DAG生成合成数据,这表明数据生成的数据再现了不同域中时间序列的众所周知的特征。然后,我们将学习方法的MN媒体与基线模型进行比较,该模型在使用不同的多尺度和非平稳设置生成的合成数据上进行了比较,从而证实了MN-Castle的良好性能。最后,我们展示了一些从MN-Castle的应用中得出的一些见解,以研究COVID-19期间7个全球股票市场的因果结构。
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本文提出了在适当的监督信息下进行分解的生成因果代表(亲爱的)学习方法。与实施潜在变量独立性的现有分解方法不同,我们考虑了一种基本利益因素可以因果关系相关的一般情况。我们表明,即使在监督下,先前具有独立先验的方法也无法解散因果关系。在这一发现的激励下,我们提出了一种称为DEAR的新的解开学习方法,该方法可以使因果可控的产生和因果代表学习。这种新公式的关键要素是使用结构性因果模型(SCM)作为双向生成模型的先验分布。然后,使用合适的GAN算法与发电机和编码器共同训练了先验,并与有关地面真相因子及其基本因果结构的监督信息合并。我们提供了有关该方法的可识别性和渐近收敛性的理论理由。我们对合成和真实数据集进行了广泛的实验,以证明DEAR在因果可控生成中的有效性,以及在样本效率和分布鲁棒性方面,学到的表示表示对下游任务的好处。
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从观察数据中学习因果结构是机器学习的基本挑战。但是,大多数常用的可区分因果发现方法是不可识别的,这将此问题变成了容易发生数据偏差的连续优化任务。在许多现实生活中,数据是从不同环境中收集的,在不同的环境中,功能关系在整个环境中保持一致,而添加噪声的分布可能会有所不同。本文提出了可区分的因果发现(DICD),利用基于可区分框架的多环境信息,以避免学习虚假边缘和错误的因果方向。具体而言,DICD旨在在消除环境依赖性相关性的同时发现环境不变的因果关系。我们进一步制定了强制执行目标结构方程模型的约束,以在整个环境中保持最佳状态。在温和条件下提供了足够的环境,提供了针对拟议DICD的可识别性的理论保证。关于合成和现实世界数据集的广泛实验验证了DICD优于最先进的因果发现方法,而SHD中最高36%。我们的代码将是开源的。
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在许多学科中,在大量解释变量中推断反应变量的直接因果父母的问题具有很高的实际意义。但是,建立的方法通常至少会随着解释变量的数量而呈指数级扩展,难以扩展到非线性关系,并且很难扩展到周期性数据。受{\ em Debiased}机器学习方法的启发,我们研究了一种单Vs.-the-Rest特征选择方法,以发现响应的直接因果父母。我们提出了一种用于纯观测数据的算法,同时还提供理论保证,包括可能在周期存在下的部分非线性关系的情况。由于它仅需要对每个变量进行一个估计,因此我们的方法甚至适用于大图。与既定方法相比,我们证明了显着改善。
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Linear structural causal models (SCMs)-- in which each observed variable is generated by a subset of the other observed variables as well as a subset of the exogenous sources-- are pervasive in causal inference and casual discovery. However, for the task of causal discovery, existing work almost exclusively focus on the submodel where each observed variable is associated with a distinct source with non-zero variance. This results in the restriction that no observed variable can deterministically depend on other observed variables or latent confounders. In this paper, we extend the results on structure learning by focusing on a subclass of linear SCMs which do not have this property, i.e., models in which observed variables can be causally affected by any subset of the sources, and are allowed to be a deterministic function of other observed variables or latent confounders. This allows for a more realistic modeling of influence or information propagation in systems. We focus on the task of causal discovery form observational data generated from a member of this subclass. We derive a set of necessary and sufficient conditions for unique identifiability of the causal structure. To the best of our knowledge, this is the first work that gives identifiability results for causal discovery under both latent confounding and deterministic relationships. Further, we propose an algorithm for recovering the underlying causal structure when the aforementioned conditions are satisfied. We validate our theoretical results both on synthetic and real datasets.
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