Federated learning (FL) is an emerging machine learning paradigm, in which clients jointly learn a model with the help of a cloud server. A fundamental challenge of FL is that the clients are often heterogeneous, e.g., they have different computing powers, and thus the clients may send model updates to the server with substantially different delays. Asynchronous FL aims to address this challenge by enabling the server to update the model once any client's model update reaches it without waiting for other clients' model updates. However, like synchronous FL, asynchronous FL is also vulnerable to poisoning attacks, in which malicious clients manipulate the model via poisoning their local data and/or model updates sent to the server. Byzantine-robust FL aims to defend against poisoning attacks. In particular, Byzantine-robust FL can learn an accurate model even if some clients are malicious and have Byzantine behaviors. However, most existing studies on Byzantine-robust FL focused on synchronous FL, leaving asynchronous FL largely unexplored. In this work, we bridge this gap by proposing AFLGuard, a Byzantine-robust asynchronous FL method. We show that, both theoretically and empirically, AFLGuard is robust against various existing and adaptive poisoning attacks (both untargeted and targeted). Moreover, AFLGuard outperforms existing Byzantine-robust asynchronous FL methods.

Decentralized bilevel optimization has received increasing attention recently due to its foundational role in many emerging multi-agent learning paradigms (e.g., multi-agent meta-learning and multi-agent reinforcement learning) over peer-to-peer edge networks. However, to work with the limited computation and communication capabilities of edge networks, a major challenge in developing decentralized bilevel optimization techniques is to lower sample and communication complexities. This motivates us to develop a new decentralized bilevel optimization called DIAMOND (decentralized single-timescale stochastic approximation with momentum and gradient-tracking). The contributions of this paper are as follows: i) our DIAMOND algorithm adopts a single-loop structure rather than following the natural double-loop structure of bilevel optimization, which offers low computation and implementation complexity; ii) compared to existing approaches, the DIAMOND algorithm does not require any full gradient evaluations, which further reduces both sample and computational complexities; iii) through a careful integration of momentum information and gradient tracking techniques, we show that the DIAMOND algorithm enjoys $\mathcal{O}(\epsilon^{-3/2})$ in sample and communication complexities for achieving an $\epsilon$-stationary solution, both of which are independent of the dataset sizes and significantly outperform existing works. Extensive experiments also verify our theoretical findings.

Heterogeneous treatment effects (HTEs) are commonly identified during randomized controlled trials (RCTs). Identifying subgroups of patients with similar treatment effects is of high interest in clinical research to advance precision medicine. Often, multiple clinical outcomes are measured during an RCT, each having a potentially heterogeneous effect. Recently there has been high interest in identifying subgroups from HTEs, however, there has been less focus on developing tools in settings where there are multiple outcomes. In this work, we propose a framework for partitioning the covariate space to identify subgroups across multiple outcomes based on the joint CIs. We test our algorithm on synthetic and semi-synthetic data where there are two outcomes, and demonstrate that our algorithm is able to capture the HTE in both outcomes simultaneously.

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.

团队是人类成就的核心。在过去的半个世纪中，心理学家已经确定了五个跨文化有效的人格变量：神经质，外向性，开放性，尽职尽责和同意。前四个与团队绩效显示一致的关系。然而，令人愉快的（和谐，无私，谦虚和合作）表现出与团队绩效的无关紧要和高度可变的关系。我们通过计算建模解决这种不一致。基于代理的模型（ABM）用于预测人格特质对团队合作的影响，然后使用遗传算法来探索ABM的限制，以发现哪种特征与最佳和最差的表现相关，以解决与与最差的团队相关的问题，以解决与问题有关的问题。不同级别的不确定性（噪声）。探索所揭示的新依赖性通过分析迄今为止最大的团队绩效数据集的先前未观察到的数据来证实，其中包括593个团队中的3,698个个人，从事5,000多个没有不确定性的小组任务，在10年内收集了不确定性。我们的发现是，团队绩效和同意之间的依赖性受到任务不确定性的调节。以这种方式将进化计算与ABM相结合，为团队合作的科学研究，做出新的预测以及提高我们对人类行为的理解提供了一种新方法。我们的结果证实了计算机建模对发展理论的潜在实用性，并阐明了随着工作环境的越来越流畅和不确定的启示。

语言模型既展示了定量的改进，又展示了新的定性功能，随着规模的增加。尽管它们具有潜在的变革性影响，但这些新能力的特征却很差。为了为未来的研究提供信息，为破坏性的新模型能力做准备，并改善社会有害的效果，至关重要的是，我们必须了解目前和近乎未来的能力和语言模型的局限性。为了应对这一挑战，我们介绍了超越模仿游戏基准（Big Bench）。 Big Bench目前由204个任务组成，由132家机构的442位作者贡献。任务主题是多样的，从语言学，儿童发展，数学，常识性推理，生物学，物理学，社会偏见，软件开发等等。 Big-Bench专注于被认为超出当前语言模型的功能的任务。我们评估了OpenAI的GPT型号，Google内部密集变压器体系结构和大型基础上的开关稀疏变压器的行为，跨越了数百万到数十亿个参数。此外，一个人类专家评估者团队执行了所有任务，以提供强大的基准。研究结果包括：模型性能和校准都随规模改善，但绝对的术语（以及与评估者的性能相比）；在模型类中的性能非常相似，尽管带有稀疏性。逐渐和预测的任务通常涉及大量知识或记忆成分，而在临界规模上表现出“突破性”行为的任务通常涉及多个步骤或组成部分或脆性指标；社交偏见通常会随着含糊不清的环境而随着规模而增加，但这可以通过提示来改善。

在本文中，我们研究了多语言句子嵌入的使用，以转移跨管辖区，法律制度（普通和民法），语言和域名的审判决策功能分割的预测模型（即语境）。利用原始环境之外的语言资源的机制在AI和法律中具有显着的潜在利益，因为法律制度，语言或传统之间的差异往往阻碍了更广泛的研究结果。我们使用跨语言可转换的门控复发单元（GRUS）分析使用语言无话句子表示的使用。调查不同背景之间的转移，我们开发了一种审判决策功能分割的注释方案。我们发现模特超出了他们接受培训的背景（例如，在美国的行政决定上培训的模型可以应用于意大利的刑法决定）。此外，我们发现在多种上下文上培训模型增加了鲁棒性并在评估先前看不见的上下文时提高整体性能。最后，我们发现，从所有上下文中汇集训练数据增强了模型的上下文性能。

我们研究了点击流行为中预测在线课程中学生知识获取的问题。通过电子学习讲座交付的激增，我们专注于讲座视频中的学生在视频活动中，由内容和视频测验组成。我们预测视频测验性能的方法基于我们开发的三个关键思路。首先，我们通过在原始事件数据上运行的时间序列学习架构模拟学生的点击行为，而不是定义可能在现有方法中定义手工制作的功能，可能丢失在单击序列内的重要信息。其次，我们开发了一个自我监督的Clickstream预培训，以学习Clickstream事件的信息表示，可以有效地初始化预测模型。第三，我们提出了一种基于聚类的基于元学习的培训，可以优化预测模型，以利用学生点击流序列中的频繁模式集群。通过对三个现实世界数据集的实验，我们证明我们的方法在预测学生的视频测验性能方面的两个基线模型中获得了大量改进。此外，我们通过消融研究验证了我们框架的预培训和元学习组成部分的重要性。最后，我们展示了我们的方法论如何了解与有用的学习分析有用的知识获取相关的视频监视行为的见解。

疟疾是一种威胁生命的疾病，影响了数百万。基于显微镜的薄膜评估是（i）确定疟疾物种和（ii）定量高寄生虫感染的标准方法。通过机器学习（ML）对疟疾显微镜的完全自动化是一项具有挑战性的任务，因为预先准备的滑动在质量和表现方面差异很大，并且伪像通常超过相对较少的寄生虫。在这项工作中，我们描述了一个用于薄膜疟疾分析的完整，完全自动化的框架，该框架应用了ML方法，包括卷积神经网（CNN），该方法在大型且多样化的田间预先准备的薄膜数据集中进行了训练。定量和物种鉴定结果几乎足够准确地满足了耐药性监测和临床用例的混凝土需求。我们将方法和性能指标集中在现场用例要求上。我们讨论了将ML方法应用于疟疾显微镜的关键问题和重要指标。

Designing experiments often requires balancing between learning about the true treatment effects and earning from allocating more samples to the superior treatment. While optimal algorithms for the Multi-Armed Bandit Problem (MABP) provide allocation policies that optimally balance learning and earning, they tend to be computationally expensive. The Gittins Index (GI) is a solution to the MABP that can simultaneously attain optimality and computationally efficiency goals, and it has been recently used in experiments with Bernoulli and Gaussian rewards. For the first time, we present a modification of the GI rule that can be used in experiments with exponentially-distributed rewards. We report its performance in simulated 2- armed and 3-armed experiments. Compared to traditional non-adaptive designs, our novel GI modified design shows operating characteristics comparable in learning (e.g. statistical power) but substantially better in earning (e.g. direct benefits). This illustrates the potential that designs using a GI approach to allocate participants have to improve participant benefits, increase efficiencies, and reduce experimental costs in adaptive multi-armed experiments with exponential rewards.