Causal disentanglement seeks a representation of data involving latent variables that relate to one another via a causal model. A representation is identifiable if both the latent model and the transformation from latent to observed variables are unique. In this paper, we study observed variables that are a linear transformation of a linear latent causal model. Data from interventions are necessary for identifiability: if one latent variable is missing an intervention, we show that there exist distinct models that cannot be distinguished. Conversely, we show that a single intervention on each latent variable is sufficient for identifiability. Our proof uses a generalization of the RQ decomposition of a matrix that replaces the usual orthogonal and upper triangular conditions with analogues depending on a partial order on the rows of the matrix, with partial order determined by a latent causal model. We corroborate our theoretical results with a method for causal disentanglement that accurately recovers a latent causal model.
translated by 谷歌翻译
跨学科的一个重要问题是发现产生预期结果的干预措施。当可能的干预空间很大时,需要进行详尽的搜索,需要实验设计策略。在这种情况下,编码变量之间的因果关系以及因此对系统的影响,对于有效地确定理想的干预措施至关重要。我们开发了一种迭代因果方法来识别最佳干预措施,这是通过分布后平均值和所需目标平均值之间的差异来衡量的。我们制定了一种主动学习策略,该策略使用从不同干预措施中获得的样本来更新有关基本因果模型的信念,并确定对最佳干预措施最有用的样本,因此应在下一批中获得。该方法采用了因果模型的贝叶斯更新,并使用精心设计的,有因果关系的收购功能优先考虑干预措施。此采集函数以封闭形式进行评估,从而有效优化。理论上以信息理论界限和可证明的一致性结果在理论上基于理论上的算法。我们说明了综合数据和现实世界生物学数据的方法,即来自worturb-cite-seq实验的基因表达数据,以识别诱导特定细胞态过渡的最佳扰动;与几个基线相比,观察到所提出的因果方法可实现更好的样品效率。在这两种情况下,我们都认为因果知情的采集函数尤其优于现有标准,从而允许使用实验明显更少的最佳干预设计。
translated by 谷歌翻译
In this review, we discuss approaches for learning causal structure from data, also called causal discovery. In particular, we focus on approaches for learning directed acyclic graphs (DAGs) and various generalizations which allow for some variables to be unobserved in the available data. We devote special attention to two fundamental combinatorial aspects of causal structure learning. First, we discuss the structure of the search space over causal graphs. Second, we discuss the structure of equivalence classes over causal graphs, i.e., sets of graphs which represent what can be learned from observational data alone, and how these equivalence classes can be refined by adding interventional data.
translated by 谷歌翻译
为优化方法建立快速的收敛速率对其在实践中的适用性至关重要。随着过去十年深入学习的普及,随机梯度下降及其自适应变体(例如,Adagagrad,Adam等)已成为机器学习从业者的突出方法。虽然大量作品已经证明,这些第一订单优化方法可以实现亚线性或线性收敛,但我们建立了随机梯度下降的局部二次收敛,具有自适应步长,矩阵反转等问题。
translated by 谷歌翻译
因果结构学习是许多领域的关键问题。通过对感兴趣系统进行实验来学习因果结构。我们解决了设计一批实验的主要原因,每个实验中同时干预多个变量。虽然可能比常用的单变干预措施更具信息丰富,但选择这种干预措施是更具挑战性的,这是由于复合干预措施的双指数组合搜索空间。在本文中,我们开发有效的算法,以优化量化预算限制批次实验的信息性的不同目标函数。通过建立这些目标的新型子模具性质,我们为我们的算法提供近似保证。我们的算法经验上优于随机干预和算法,只能选择单变化干预。
translated by 谷歌翻译
在本文中,我们呈现超级OT,这是一种新的计算谱系追踪方法,其基于生成的对抗网络(GANS)将监督学习框架结合了具有最优传输的监督学习框架。与以前的谱系追踪方法不同,Super-OT具有集成配对数据的灵活性。我们基于针对Waddington-OT的单细胞RNA-SEQ数据进行基于单细胞RNA-SEQ数据的基准测试,这是一种谱系追踪的流行方法,也采用了最佳运输。我们展示超级OT在预测分化期间预测细胞的阶级结果时,Super-Ot达到了vaddington-ot。它允许在培训期间整合附加信息。
translated by 谷歌翻译
The number of international benchmarking competitions is steadily increasing in various fields of machine learning (ML) research and practice. So far, however, little is known about the common practice as well as bottlenecks faced by the community in tackling the research questions posed. To shed light on the status quo of algorithm development in the specific field of biomedical imaging analysis, we designed an international survey that was issued to all participants of challenges conducted in conjunction with the IEEE ISBI 2021 and MICCAI 2021 conferences (80 competitions in total). The survey covered participants' expertise and working environments, their chosen strategies, as well as algorithm characteristics. A median of 72% challenge participants took part in the survey. According to our results, knowledge exchange was the primary incentive (70%) for participation, while the reception of prize money played only a minor role (16%). While a median of 80 working hours was spent on method development, a large portion of participants stated that they did not have enough time for method development (32%). 25% perceived the infrastructure to be a bottleneck. Overall, 94% of all solutions were deep learning-based. Of these, 84% were based on standard architectures. 43% of the respondents reported that the data samples (e.g., images) were too large to be processed at once. This was most commonly addressed by patch-based training (69%), downsampling (37%), and solving 3D analysis tasks as a series of 2D tasks. K-fold cross-validation on the training set was performed by only 37% of the participants and only 50% of the participants performed ensembling based on multiple identical models (61%) or heterogeneous models (39%). 48% of the respondents applied postprocessing steps.
translated by 谷歌翻译
Polypharmacy, most often defined as the simultaneous consumption of five or more drugs at once, is a prevalent phenomenon in the older population. Some of these polypharmacies, deemed inappropriate, may be associated with adverse health outcomes such as death or hospitalization. Considering the combinatorial nature of the problem as well as the size of claims database and the cost to compute an exact association measure for a given drug combination, it is impossible to investigate every possible combination of drugs. Therefore, we propose to optimize the search for potentially inappropriate polypharmacies (PIPs). To this end, we propose the OptimNeuralTS strategy, based on Neural Thompson Sampling and differential evolution, to efficiently mine claims datasets and build a predictive model of the association between drug combinations and health outcomes. We benchmark our method using two datasets generated by an internally developed simulator of polypharmacy data containing 500 drugs and 100 000 distinct combinations. Empirically, our method can detect up to 33\% of PIPs while maintaining an average precision score of 99\% using 10 000 time steps.
translated by 谷歌翻译
平行操纵器的配置歧管比串行操纵器表现出更多的非线性。从定性上讲,它们可以看到额外的褶皱。通过将这种歧管投射到工程相关性的空间上,例如输出工作区或输入执行器空间,这些折叠式的边缘呈现出表现非滑动行为的边缘。例如,在五杆链接的全局工作空间边界内显示了几个局部工作空间边界,这些边界仅限于该机制的某些输出模式。当专门研究这些投影而不是配置歧管本身时,这种边界的存在在输入和输出投影中都表现出来。特别是,非对称平行操纵器的设计已被其输入和输出空间中的外来投影所困扰。在本文中,我们用半径图表示配置空间,然后通过使用同型延续来量化传输质量来解决每个边缘。然后,我们采用图路径计划器来近似于避免传输质量区域的配置点之间的大地测量。我们的方法会自动生成能够在非邻居输出模式之间过渡的路径,该运动涉及示波多个工作空间边界(局部,全局或两者)。我们将技术应用于两个非对称五杆示例,这些示例表明如何通过切换输出模式来选择工作空间的传输属性和其他特征。
translated by 谷歌翻译
由多种因素引起的组织学图像的染色变化不仅是病理学家的视觉诊断,而且是细胞分割算法的挑战。为了消除颜色变化,已经提出了许多染色归一化方法。但是,大多数是为苏木精和曙红染色图像而设计的,并且在免疫组织化学染色图像上表现不佳。当前的细胞分割方法系统地将染色归一化作为预处理步骤,但是尚未定量研究颜色变化带来的影响。在本文中,我们制作了五组具有不同颜色的Neun染色图像。我们应用了一种深度学习的图像录制方法来在组织学图像组之间执行色彩转移。最后,我们改变了分割集的颜色,并量化了颜色变化对细胞分割的影响。结果证明了在后续分析之前必须进行颜色归一化的必要性。
translated by 谷歌翻译