Covid-19疾病迅速蔓延，在中国确认第一个积极案件后近三个月，冠状病毒开始遍布美国。一些州和县报告了大量的积极病例和死亡，而一些据报道的Covid-19相关病例和死亡率。本文在县级分析了可能影响Covid-19感染和死亡率风险的因素。使用K-Means聚类和多种分类模型的创新方法来确定最关键的因素。结果表明，平均温度，低于贫困人数，肥胖，空气压力，人口密度，风力速度，经度和未知人民百分比的成年人的百分比是最重要的属性

Reinforcement learning (RL) has shown great promise with algorithms learning in environments with large state and action spaces purely from scalar reward signals. A crucial challenge for current deep RL algorithms is that they require a tremendous amount of environment interactions for learning. This can be infeasible in situations where such interactions are expensive; such as in robotics. Offline RL algorithms try to address this issue by bootstrapping the learning process from existing logged data without needing to interact with the environment from the very beginning. While online RL algorithms are typically evaluated as a function of the number of environment interactions, there exists no single established protocol for evaluating offline RL methods.In this paper, we propose a sequential approach to evaluate offline RL algorithms as a function of the training set size and thus by their data efficiency. Sequential evaluation provides valuable insights into the data efficiency of the learning process and the robustness of algorithms to distribution changes in the dataset while also harmonizing the visualization of the offline and online learning phases. Our approach is generally applicable and easy to implement. We compare several existing offline RL algorithms using this approach and present insights from a variety of tasks and offline datasets.

The reconstruction of images from their corresponding noisy Radon transform is a typical example of an ill-posed linear inverse problem as arising in the application of computerized tomography (CT). As the (na\"{\i}ve) solution does not depend on the measured data continuously, regularization is needed to re-establish a continuous dependence. In this work, we investigate simple, but yet still provably convergent approaches to learning linear regularization methods from data. More specifically, we analyze two approaches: One generic linear regularization that learns how to manipulate the singular values of the linear operator in an extension of [1], and one tailored approach in the Fourier domain that is specific to CT-reconstruction. We prove that such approaches become convergent regularization methods as well as the fact that the reconstructions they provide are typically much smoother than the training data they were trained on. Finally, we compare the spectral as well as the Fourier-based approaches for CT-reconstruction numerically, discuss their advantages and disadvantages and investigate the effect of discretization errors at different resolutions.

Humans have perfected the art of learning from multiple modalities through sensory organs. Despite their impressive predictive performance on a single modality, neural networks cannot reach human level accuracy with respect to multiple modalities. This is a particularly challenging task due to variations in the structure of respective modalities. Conditional Batch Normalization (CBN) is a popular method that was proposed to learn contextual features to aid deep learning tasks. This technique uses auxiliary data to improve representational power by learning affine transformations for convolutional neural networks. Despite the boost in performance observed by using CBN layers, our work reveals that the visual features learned by introducing auxiliary data via CBN deteriorates. We perform comprehensive experiments to evaluate the brittleness of CBN networks to various datasets, suggesting that learning from visual features alone could often be superior for generalization. We evaluate CBN models on natural images for bird classification and histology images for cancer type classification. We observe that the CBN network learns close to no visual features on the bird classification dataset and partial visual features on the histology dataset. Our extensive experiments reveal that CBN may encourage shortcut learning between the auxiliary data and labels.

Current pre-trained language models rely on large datasets for achieving state-of-the-art performance. However, past research has shown that not all examples in a dataset are equally important during training. In fact, it is sometimes possible to prune a considerable fraction of the training set while maintaining the test performance. Established on standard vision benchmarks, two gradient-based scoring metrics for finding important examples are GraNd and its estimated version, EL2N. In this work, we employ these two metrics for the first time in NLP. We demonstrate that these metrics need to be computed after at least one epoch of fine-tuning and they are not reliable in early steps. Furthermore, we show that by pruning a small portion of the examples with the highest GraNd/EL2N scores, we can not only preserve the test accuracy, but also surpass it. This paper details adjustments and implementation choices which enable GraNd and EL2N to be applied to NLP.

Large language models (LLMs) have been shown to be able to perform new tasks based on a few demonstrations or natural language instructions. While these capabilities have led to widespread adoption, most LLMs are developed by resource-rich organizations and are frequently kept from the public. As a step towards democratizing this powerful technology, we present BLOOM, a 176B-parameter open-access language model designed and built thanks to a collaboration of hundreds of researchers. BLOOM is a decoder-only Transformer language model that was trained on the ROOTS corpus, a dataset comprising hundreds of sources in 46 natural and 13 programming languages (59 in total). We find that BLOOM achieves competitive performance on a wide variety of benchmarks, with stronger results after undergoing multitask prompted finetuning. To facilitate future research and applications using LLMs, we publicly release our models and code under the Responsible AI License.

强化学习（RL）的成功在很大程度上取决于从环境观察中学习强大表示的能力。在大多数情况下，根据价值功能的变化，在各州之间纯粹通过强化学习损失所学的表示形式可能会有很大差异。但是，所学的表示形式不必非常具体地针对手头的任务。仅依靠RL目标可能会产生在连续的时间步骤中变化很大的表示形式。此外，由于RL损失的目标变化，因此所学的表示将取决于当前价值/策略的良好。因此，从主要任务中解开表示形式将使他们更多地专注于捕获可以改善概括的过渡动态。为此，我们提出了局部约束的表示，辅助损失迫使国家表示由邻近状态的表示可以预测。这不仅鼓励表示形式受到价值/政策学习的驱动，还可以自我监督的学习来驱动，这会限制表示表示的变化太快。我们在几个已知的基准上评估了所提出的方法，并观察到强劲的性能。尤其是在连续控制任务中，我们的实验比强基线显示出显着的优势。

韵律在言语交流中起着至关重要的作用。韵律的声明已被广泛研究。但是，韵律特征不仅被视而不见，而且在视觉上是基于头部和面部运动的视觉上。本报告的目的是提出一种使用虚拟现实检查视听韵律的方法。我们表明，基于虚拟人的动画提供了与真正说话者视频录音相似的运动提示。虚拟现实的使用开辟了新的途径，以检查口头交流的多模式效应。我们讨论了研究人工耳蜗听众中韵律感知的框架中的方法。

服务监视应用程序不断生成数据以监视其可用性。因此，实时和准确地对传入数据进行分类至关重要。为此，我们的研究开发了一种使用Learn ++来处理不断发展的数据分布的自适应分类方法。这种方法顺序预测并使用新数据更新监视模型，逐渐忘记了过去的知识并确定了突然的概念漂移。我们采用从工业应用获得的连续数据块来逐步评估预测变量的性能。

大多数强化学习算法都利用了经验重播缓冲液，以反复对代理商过去观察到的样本进行训练。这样可以防止灾难性的遗忘，但是仅仅对每个样本都分配了同等的重要性是一种天真的策略。在本文中，我们提出了一种根据样本可以从样本中学到多少样本确定样本优先级的方法。我们将样本的学习能力定义为随着时间的推移，与该样品相关的训练损失的稳定减少。我们开发了一种算法，以优先考虑具有较高学习能力的样本，同时将优先级较低，为那些难以学习的样本，通常是由噪声或随机性引起的。我们从经验上表明，我们的方法比随机抽样更强大，而且比仅在训练损失方面优先排序更好，即时间差损失，这是在香草优先的经验重播中使用的。