Directed information (DI) is a fundamental measure for the study and analysis of sequential stochastic models. In particular, when optimized over input distributions it characterizes the capacity of general communication channels. However, analytic computation of DI is typically intractable and existing optimization techniques over discrete input alphabets require knowledge of the channel model, which renders them inapplicable when only samples are available. To overcome these limitations, we propose a novel estimation-optimization framework for DI over discrete input spaces. We formulate DI optimization as a Markov decision process and leverage reinforcement learning techniques to optimize a deep generative model of the input process probability mass function (PMF). Combining this optimizer with the recently developed DI neural estimator, we obtain an end-to-end estimation-optimization algorithm which is applied to estimating the (feedforward and feedback) capacity of various discrete channels with memory. Furthermore, we demonstrate how to use the optimized PMF model to (i) obtain theoretical bounds on the feedback capacity of unifilar finite-state channels; and (ii) perform probabilistic shaping of constellations in the peak power-constrained additive white Gaussian noise channel.
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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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Recent work attributes progress in NLP to large language models (LMs) with increased model size and large quantities of pretraining data. Despite this, current state-of-the-art LMs for Hebrew are both under-parameterized and under-trained compared to LMs in other languages. Additionally, previous work on pretrained Hebrew LMs focused on encoder-only models. While the encoder-only architecture is beneficial for classification tasks, it does not cater well for sub-word prediction tasks, such as Named Entity Recognition, when considering the morphologically rich nature of Hebrew. In this paper we argue that sequence-to-sequence generative architectures are more suitable for LLMs in the case of morphologically rich languages (MRLs) such as Hebrew. We demonstrate that by casting tasks in the Hebrew NLP pipeline as text-to-text tasks, we can leverage powerful multilingual, pretrained sequence-to-sequence models as mT5, eliminating the need for a specialized, morpheme-based, separately fine-tuned decoder. Using this approach, our experiments show substantial improvements over previously published results on existing Hebrew NLP benchmarks. These results suggest that multilingual sequence-to-sequence models present a promising building block for NLP for MRLs.
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Large language models (LLMs) have shown impressive results across a variety of tasks while requiring little or no direct supervision. Further, there is mounting evidence that LLMs may have potential in information-seeking scenarios. We believe the ability of an LLM to attribute the text that it generates is likely to be crucial for both system developers and users in this setting. We propose and study Attributed QA as a key first step in the development of attributed LLMs. We develop a reproducable evaluation framework for the task, using human annotations as a gold standard and a correlated automatic metric that we show is suitable for development settings. We describe and benchmark a broad set of architectures for the task. Our contributions give some concrete answers to two key questions (How to measure attribution?, and How well do current state-of-the-art methods perform on attribution?), and give some hints as to how to address a third key question (How to build LLMs with attribution?).
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In this short paper, we present our ongoing work on the veriFIRE project -- a collaboration between industry and academia, aimed at using verification for increasing the reliability of a real-world, safety-critical system. The system we target is an airborne platform for wildfire detection, which incorporates two deep neural networks. We describe the system and its properties of interest, and discuss our attempts to verify the system's consistency, i.e., its ability to continue and correctly classify a given input, even if the wildfire it describes increases in intensity. We regard this work as a step towards the incorporation of academic-oriented verification tools into real-world systems of interest.
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Question answering models commonly have access to two sources of "knowledge" during inference time: (1) parametric knowledge - the factual knowledge encoded in the model weights, and (2) contextual knowledge - external knowledge (e.g., a Wikipedia passage) given to the model to generate a grounded answer. Having these two sources of knowledge entangled together is a core issue for generative QA models as it is unclear whether the answer stems from the given non-parametric knowledge or not. This unclarity has implications on issues of trust, interpretability and factuality. In this work, we propose a new paradigm in which QA models are trained to disentangle the two sources of knowledge. Using counterfactual data augmentation, we introduce a model that predicts two answers for a given question: one based on given contextual knowledge and one based on parametric knowledge. Our experiments on the Natural Questions dataset show that this approach improves the performance of QA models by making them more robust to knowledge conflicts between the two knowledge sources, while generating useful disentangled answers.
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保存隐私的神经网络(NN)推理解决方案最近在几种提供不同的延迟带宽权衡的解决方案方面获得了重大吸引力。其中,许多人依靠同态加密(HE),这是一种对加密数据进行计算的方法。但是,与他们的明文对应物相比,他的操作即使是最先进的计划仍然很慢。修剪NN模型的参数是改善推理潜伏期的众所周知的方法。但是,在明文上下文中有用的修剪方法可能对HE案的改善几乎可以忽略不计,这在最近的工作中也证明了这一点。在这项工作中,我们提出了一套新颖的修剪方法,以减少潜伏期和记忆要求,从而将明文修剪方法的有效性带到HE中。至关重要的是,我们的建议采用两种关键技术,即。堆积模型权重的置换和扩展,使修剪能够明显更多的密封性下文并分别恢复大部分精度损失。我们证明了我们的方法在完全连接的层上的优势,其中使用最近提出的称为瓷砖张量的包装技术填充了权重,该技术允许在非相互作用模式下执行Deep NN推断。我们在各种自动编码器架构上评估了我们的方法,并证明,对于MNIST上的小均值重建损失为1.5*10^{ - 5},我们将HE-SEAMABLE推断的内存要求和延迟减少了60%。
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切成薄片的相互信息(SMI)定义为在随机变量的一维随机投影之间的平均值(MI)项。它是对经典MI依赖的替代度量,该量子保留了许多特性,但更可扩展到高维度。但是,对SMI本身和其估计率的定量表征取决于环境维度,这对于理解可伸缩性至关重要,仍然晦涩难懂。这项工作将原始的SMI定义扩展到$ K $ -SMI,该定义将预测视为$ k $维二维子空间,并提供了有关其依赖性尺寸的多方面帐户。在2-Wasserstein指标中使用差分熵连续性的新结果,我们对Monte Carlo(MC)基于$ K $ -SMI的估计的错误得出了尖锐的界限,并明确依赖于$ K $和环境维度,揭示了他们与样品数量的相互作用。然后,我们将MC Integrator与神经估计框架相结合,以提供端到端$ K $ -SMI估算器,为此建立了最佳的收敛率。随着尺寸的增长,我们还探索了人口$ k $ -smi的渐近学,从而为高斯近似结果提供了在适当的力矩范围下衰减的残差。我们的理论通过数值实验验证,并适用于切片Infogan,该切片完全提供了$ k $ -smi的可伸缩性问题的全面定量说明,包括SMI作为特殊情况,当$ k = 1 $。
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概率分布之间的差异措施是统计推理和机器学习的核心。在许多应用中,在不同的空格上支持感兴趣的分布,需要在数据点之间进行有意义的对应。激励明确地将一致的双向图编码为差异措施,这项工作提出了一种用于匹配的新型不平衡的Monge最佳运输制剂,达到异构体,在不同空间上的分布。我们的配方由于公制空间之间的Gromov-Haussdrow距离而受到了原则放松,并且采用了两个周期一致的地图,将每个分布推向另一个分布。我们研究了拟议的差异的结构性,并且特别表明它将流行的循环一致的生成对抗网络(GaN)框架捕获为特殊情况,从而提供理论解释它。通过计算效率激励,然后我们将差异括起来并将映射限制为参数函数类。由此产生的核化版本被创建为广义最大差异(GMMD)。研究了GMMD的经验估计的收敛速率,并提供了支持我们理论的实验。
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Wassersein距离,植根于最佳运输(OT)理论,是在统计和机器学习的各种应用程序之间的概率分布之间的流行差异测量。尽管其结构丰富,但效用,但Wasserstein距离对所考虑的分布中的异常值敏感,在实践中阻碍了适用性。灵感来自Huber污染模型,我们提出了一种新的异常值 - 强大的Wasserstein距离$ \ mathsf {w} _p ^ \ varepsilon $,它允许从每个受污染的分布中删除$ \ varepsilon $异常块。与以前考虑的框架相比,我们的配方达到了高度定期的优化问题,使其更好地分析。利用这一点,我们对$ \ mathsf {w} _p ^ \ varepsilon $的彻底理论研究,包括最佳扰动,规律性,二元性和统计估算和鲁棒性结果的表征。特别是,通过解耦优化变量,我们以$ \ mathsf {w} _p ^ \ varepsilon $到达一个简单的双重形式,可以通过基于标准的基于二元性的OT响音器的基本修改来实现。我们通过应用程序来说明我们的框架的好处,以与受污染的数据集进行生成建模。
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