We introduce a novel gated recurrent unit (GRU) with a weighted time-delay feedback mechanism in order to improve the modeling of long-term dependencies in sequential data. This model is a discretized version of a continuous-time formulation of a recurrent unit, where the dynamics are governed by delay differential equations (DDEs). By considering a suitable time-discretization scheme, we propose $\tau$-GRU, a discrete-time gated recurrent unit with delay. We prove the existence and uniqueness of solutions for the continuous-time model, and we demonstrate that the proposed feedback mechanism can help improve the modeling of long-term dependencies. Our empirical results show that $\tau$-GRU can converge faster and generalize better than state-of-the-art recurrent units and gated recurrent architectures on a range of tasks, including time-series classification, human activity recognition, and speech recognition.

我们介绍了嘈杂的特征混音（NFM），这是一个廉价但有效的数据增强方法，这些方法结合了基于插值的训练和噪声注入方案。不是用凸面的示例和它们的标签的凸面组合训练，而不是在输入和特征空间中使用对数据点对的噪声扰动凸组合。该方法包括混合和歧管混合作为特殊情况，但它具有额外的优点，包括更好地平滑决策边界并实现改进的模型鲁棒性。我们提供理论要理解这一点以及NFM的隐式正则化效果。与混合和歧管混合相比，我们的理论得到了经验结果的支持，展示了NFM的优势。我们表明，在一系列计算机视觉基准数据集中，使用NFM培训的剩余网络和视觉变压器在清洁数据的预测准确性和鲁棒性之间具有有利的权衡。

最近引入的普通微分方程网络（ODE-网）在深度学习和动态系统之间建立了丰富的连接。在这项工作中，我们使用基础函数的线性组合重新考虑重量作为连续的函数，这使我们能够利用诸如功能投影的参数变换。反过来，这个视图允许我们制定处理有状态层的新型有状态ode-块。这个新的ode-块的好处是双重的：首先，它使得能够纳入有意义的连续深度批量归一代化层以实现最先进的性能;其次，它使得能够通过改变来压缩权重，而不会再培训，同时保持近最先进的性能并降低推理时间和存储器占用。使用卷积单元和（b）使用变压器编码器单元将（b）句子标记任务应用于（a）图像分类任务来证明性能。

我们为研究通过将噪声注入隐藏状态而训练的经常性神经网络（RNN）提供了一般框架。具体地，我们考虑RNN，其可以被视为由输入数据驱动的随机微分方程的离散化。该框架允许我们通过在小噪声制度中导出近似显式规范器来研究一般噪声注入方案的隐式正则化效果。我们发现，在合理的假设下，这种隐含的正规化促进了更平坦的最小值;它偏向具有更稳定动态的模型;并且，在分类任务中，它有利于具有较大分类余量的模型。获得了全局稳定性的充分条件，突出了随机稳定的现象，其中噪音注入可以在训练期间提高稳定性。我们的理论得到了经验结果支持，证明RNN对各种输入扰动具有改善的鲁棒性。

The availability of challenging benchmarks has played a key role in the recent progress of machine learning. In cooperative multi-agent reinforcement learning, the StarCraft Multi-Agent Challenge (SMAC) has become a popular testbed for centralised training with decentralised execution. However, after years of sustained improvement on SMAC, algorithms now achieve near-perfect performance. In this work, we conduct new analysis demonstrating that SMAC is not sufficiently stochastic to require complex closed-loop policies. In particular, we show that an open-loop policy conditioned only on the timestep can achieve non-trivial win rates for many SMAC scenarios. To address this limitation, we introduce SMACv2, a new version of the benchmark where scenarios are procedurally generated and require agents to generalise to previously unseen settings (from the same distribution) during evaluation. We show that these changes ensure the benchmark requires the use of closed-loop policies. We evaluate state-of-the-art algorithms on SMACv2 and show that it presents significant challenges not present in the original benchmark. Our analysis illustrates that SMACv2 addresses the discovered deficiencies of SMAC and can help benchmark the next generation of MARL methods. Videos of training are available at https://sites.google.com/view/smacv2

Estimating the probability of failure for complex real-world systems using high-fidelity computational models is often prohibitively expensive, especially when the probability is small. Exploiting low-fidelity models can make this process more feasible, but merging information from multiple low-fidelity and high-fidelity models poses several challenges. This paper presents a robust multi-fidelity surrogate modeling strategy in which the multi-fidelity surrogate is assembled using an active learning strategy using an on-the-fly model adequacy assessment set within a subset simulation framework for efficient reliability analysis. The multi-fidelity surrogate is assembled by first applying a Gaussian process correction to each low-fidelity model and assigning a model probability based on the model's local predictive accuracy and cost. Three strategies are proposed to fuse these individual surrogates into an overall surrogate model based on model averaging and deterministic/stochastic model selection. The strategies also dictate which model evaluations are necessary. No assumptions are made about the relationships between low-fidelity models, while the high-fidelity model is assumed to be the most accurate and most computationally expensive model. Through two analytical and two numerical case studies, including a case study evaluating the failure probability of Tristructural isotropic-coated (TRISO) nuclear fuels, the algorithm is shown to be highly accurate while drastically reducing the number of high-fidelity model calls (and hence computational cost).

TRISTRUCCUCTIONATIOPIC（TRISO）涂层颗粒燃料是强大的核燃料，并确定其可靠性对于先进的核技术的成功至关重要。然而，Triso失效概率很小，相关的计算模型很昂贵。我们使用耦合的主动学习，多尺度建模和子集模拟来估计使用几个1D和2D模型的Triso燃料的故障概率。通过多尺度建模，我们用来自两个低保真（LF）模型的信息融合，取代了昂贵的高保真（HF）模型评估。对于1D TRISO模型，我们考虑了三种多倍性建模策略：仅克里格，Kriging LF预测加克里格校正，深神经网络（DNN）LF预测加克里格校正。虽然这些多尺度建模策略的结果令人满意地比较了从两个LF模型中使用信息融合的策略，但是通常常常称为HF模型。接下来，对于2D Triso模型，我们考虑了两个多倍性建模策略：DNN LF预测加克里格校正（数据驱动）和1D Triso LF预测加克里格校正（基于物理学）。正如所预期的那样，基于物理的策略一直需要对HF模型的最少的呼叫。然而，由于DNN预测是瞬时的，数据驱动的策略具有较低的整体模拟时间，并且1D Triso模型需要不可忽略的模拟时间。

制定了具有机器学习模拟（骆驼）项目的宇宙学和天体物理学，通过数千名宇宙的流体动力模拟和机器学习将宇宙学与天体物理学结合起来。骆驼包含4,233个宇宙学仿真，2,049个n-body和2,184个最先进的流体动力模拟，在参数空间中采样巨大的体积。在本文中，我们介绍了骆驼公共数据发布，描述了骆驼模拟的特性和由它们产生的各种数据产品，包括光环，次麦，银河系和空隙目录，功率谱，Bispectra，Lyman - $ \ Alpha $光谱，概率分布函数，光环径向轮廓和X射线光子列表。我们还释放了超过骆驼 - 山姆的数十亿个星系的目录：与Santa Cruz半分析模型相结合的大量N身体模拟。我们释放包含350多个Terabytes的所有数据，并包含143,922个快照，数百万光环，星系和摘要统计数据。我们提供有关如何访问，下载，读取和处理数据AT \ URL {https://camels.readthedocs.io}的进一步技术详细信息。

尽管数据增强和转移学习有所进步，但卷积神经网络（CNNS）难以推广到看不见的域。在分割大脑扫描时，CNN对分辨率和对比度的变化非常敏感：即使在相同的MRI模式内，则性能可能会跨数据集减少。在这里，我们介绍了Synthseg，第一个分段CNN无关紧要对比和分辨率。 Synthseg培训，用从分段上的生成模型采样的合成数据培训。至关重要，我们采用域随机化策略，我们完全随机开启了合成培训数据的对比度和解决。因此，Synthseg可以在没有再培训或微调的情况下对任何目标结构域进行真实扫描，这是首次分析大量的异构临床数据。因为Synthseg仅需要进行培训（无图像），所以它可以从通过不同群体的对象（例如，老化和患病）的自动化方法获得的标签中学习，从而实现广泛的形态变异性的鲁棒性。我们展示了Synthseg在六种方式的5,300扫描和十项决议中，与监督CNN，最先进的域适应和贝叶斯分割相比，它表现出无与伦比的泛化。最后，我们通过将其施加到心脏MRI和CT分割来证明SyntheeG的恒定性。

The recent increase in public and academic interest in preserving biodiversity has led to the growth of the field of conservation technology. This field involves designing and constructing tools that utilize technology to aid in the conservation of wildlife. In this article, we will use case studies to demonstrate the importance of designing conservation tools with human-wildlife interaction in mind and provide a framework for creating successful tools. These case studies include a range of complexities, from simple cat collars to machine learning and game theory methodologies. Our goal is to introduce and inform current and future researchers in the field of conservation technology and provide references for educating the next generation of conservation technologists. Conservation technology not only has the potential to benefit biodiversity but also has broader impacts on fields such as sustainability and environmental protection. By using innovative technologies to address conservation challenges, we can find more effective and efficient solutions to protect and preserve our planet's resources.