本文研究了主题模型中高维,离散,可能稀疏的混合模型的估计。数据包括在$ n $独立文档中观察到的$ p $单词的多项式计数。在主题模型中,$ p \ times n $预期的单词频率矩阵被认为被分解为$ p \ times k $ word-top-topic矩阵$ a $ a $和a $ k \ times n $ topic-document $ t $ t $ 。由于两个矩阵的列代表属于概率简单的条件概率,因此$ a $的列被视为$ p $ - 二维混合组件,这些混合组件是所有文档共有的,而$ t $的列被视为$ k $二维的混合物特定文档并允许稀疏的权重。主要的兴趣是提供鲜明的,有限的样本,$ \ ell_1 $ norm收敛速率,用于混合物重量$ t $的估计量,当$ a $是已知或未知时。对于已知的$ a $,我们建议MLE估计为$ t $。我们对MLE的非标准分析不仅建立了其$ \ ell_1 $收敛率,而且揭示了一个非凡的属性:MLE,没有额外的正则化,可能完全稀疏,并且包含$ t $的真实零模式。我们进一步表明,MLE既是最佳的最佳选择,又适应了一大批稀疏主题分布中未知的稀疏性。当$ a $未知时,我们通过优化与$ a $ a $的插件的可能性功能来估计$ t $。对于任何满足与$ a $ $ a $的详细条件的估计器$ \ hat {a} $,显示出$ t $的估计器可保留为MLE建立的属性。环境尺寸$ k $和$ p $可以随着样本量而增长。我们的应用是对文档生成分布之间1-Wasserstein距离的估计。我们建议,估计和分析两个概率文档表示之间的新1-Wasserstein距离。
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Many business workflows require extracting important fields from form-like documents (e.g. bank statements, bills of lading, purchase orders, etc.). Recent techniques for automating this task work well only when trained with large datasets. In this work we propose a novel data augmentation technique to improve performance when training data is scarce, e.g. 10-250 documents. Our technique, which we call FieldSwap, works by swapping out the key phrases of a source field with the key phrases of a target field to generate new synthetic examples of the target field for use in training. We demonstrate that this approach can yield 1-7 F1 point improvements in extraction performance.
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Image-text multimodal representation learning aligns data across modalities and enables important medical applications, e.g., image classification, visual grounding, and cross-modal retrieval. In this work, we establish a connection between multimodal representation learning and multiple instance learning. Based on this connection, we propose a generic framework for constructing permutation-invariant score functions with many existing multimodal representation learning approaches as special cases. Furthermore, we use the framework to derive a novel contrastive learning approach and demonstrate that our method achieves state-of-the-art results on a number of downstream tasks.
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Communication enables agents to cooperate to achieve their goals. Learning when to communicate, i.e., sparse (in time) communication, and whom to message is particularly important when bandwidth is limited. Recent work in learning sparse individualized communication, however, suffers from high variance during training, where decreasing communication comes at the cost of decreased reward, particularly in cooperative tasks. We use the information bottleneck to reframe sparsity as a representation learning problem, which we show naturally enables lossless sparse communication at lower budgets than prior art. In this paper, we propose a method for true lossless sparsity in communication via Information Maximizing Gated Sparse Multi-Agent Communication (IMGS-MAC). Our model uses two individualized regularization objectives, an information maximization autoencoder and sparse communication loss, to create informative and sparse communication. We evaluate the learned communication `language' through direct causal analysis of messages in non-sparse runs to determine the range of lossless sparse budgets, which allow zero-shot sparsity, and the range of sparse budgets that will inquire a reward loss, which is minimized by our learned gating function with few-shot sparsity. To demonstrate the efficacy of our results, we experiment in cooperative multi-agent tasks where communication is essential for success. We evaluate our model with both continuous and discrete messages. We focus our analysis on a variety of ablations to show the effect of message representations, including their properties, and lossless performance of our model.
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Contrails, short for condensation trails, are line-shaped ice clouds produced by aircraft engine exhaust when they fly through cold and humid air. They generate a greenhouse effect by absorbing or directing back to Earth approximately 33% of emitted outgoing longwave radiation. They account for over half of the climate change resulting from aviation activities. Avoiding contrails and adjusting flight routes could be an inexpensive and effective way to reduce their impact. An accurate, automated, and reliable detection algorithm is required to develop and evaluate contrail avoidance strategies. Advancement in contrail detection has been severely limited due to several factors, primarily due to a lack of quality-labeled data. Recently, proposed a large human-labeled Landsat-8 contrails dataset. Each contrail is carefully labeled with various inputs in various scenes of Landsat-8 satellite imagery. In this work, we benchmark several popular segmentation models with combinations of different loss functions and encoder backbones. This work is the first to apply state-of-the-art segmentation techniques to detect contrails in low-orbit satellite imagery. Our work can also be used as an open benchmark for contrail segmentation and is publicly available.
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As predictive models are increasingly being employed to make consequential decisions, there is a growing emphasis on developing techniques that can provide algorithmic recourse to affected individuals. While such recourses can be immensely beneficial to affected individuals, potential adversaries could also exploit these recourses to compromise privacy. In this work, we make the first attempt at investigating if and how an adversary can leverage recourses to infer private information about the underlying model's training data. To this end, we propose a series of novel membership inference attacks which leverage algorithmic recourse. More specifically, we extend the prior literature on membership inference attacks to the recourse setting by leveraging the distances between data instances and their corresponding counterfactuals output by state-of-the-art recourse methods. Extensive experimentation with real world and synthetic datasets demonstrates significant privacy leakage through recourses. Our work establishes unintended privacy leakage as an important risk in the widespread adoption of recourse methods.
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Deep Ensemble Convolutional Neural Networks has become a methodology of choice for analyzing medical images with a diagnostic performance comparable to a physician, including the diagnosis of Diabetic Retinopathy. However, commonly used techniques are deterministic and are therefore unable to provide any estimate of predictive uncertainty. Quantifying model uncertainty is crucial for reducing the risk of misdiagnosis. A reliable architecture should be well-calibrated to avoid over-confident predictions. To address this, we propose a UATTA-ENS: Uncertainty-Aware Test-Time Augmented Ensemble Technique for 5 Class PIRC Diabetic Retinopathy Classification to produce reliable and well-calibrated predictions.
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流行模型是理解传染病的强大工具。但是,随着它们的大小和复杂性的增加,它们可以迅速在计算上棘手。建模方法的最新进展表明,替代模型可用于模拟具有高维参数空间的复杂流行模型。我们表明,深层序列到序列(SEQ2SEQ)模型可以作为具有基于序列模型参数的复杂流行病模型的准确替代物,从而有效地复制了季节性和长期传播动力学。一旦受过培训,我们的代理人可以预测场景比原始模型快几千倍,从而使其非常适合策略探索。我们证明,用博学的模拟器代替传统的流行模型有助于强大的贝叶斯推断。
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我们提出了一种确定性等效方案,以自适应控制标量线性系统,约为I.I.D.高斯干扰和有限的控制输入约束,而无需先验系统参数的界限,也不需要控制方向。假设该系统处于偏差稳定的范围内,则证明了闭环系统状态的均方根界。最后,提出了数值示例,以说明我们的结果。
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本文介绍了Apamant,这是一组软件模块,可为现有的机器人计划和控制软件框架提供掌握计划功能。我们提出的工作允许用户调整操作任务,以在不同的情况下使用最小的用户输入,从而减少操作员的认知负载。开发的工具包括(1)基于插件的组件,使得易于扩展默认功能并使用第三方Grasp库,(2)以对象为中心的方式来定义任务约束,(3)用户友好的RVIZ接口使用GRASP计划者实用程序,以及(4)使用感知数据来编程任务的交互式工具。我们在各种机器人模拟上测试了框架。
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