水生运动是生物学家和工程师感兴趣的经典流体结构相互作用（FSI）问题。求解完全耦合的FSI方程，用于不可压缩的Navier-Stokes和有限的弹性在计算上是昂贵的。在这种系统中，优化机器人游泳器设计通常涉及在已经昂贵的模拟之上繁琐的，无梯度的程序。为了应对这一挑战，我们提出了一种针对FSI的新颖，完全可区分的混合方法，该方法结合了2D直接数值模拟，用于游泳器的可变形固体结构和物理受限的神经网络替代物，以捕获流体的流体动力效应。对于游泳者身体的可变形实心模拟，我们使用来自计算机图形领域的最新技术来加快有限元方法（FEM）。对于流体模拟，我们使用经过基于物理损耗功能的U-NET体系结构来预测每个时间步骤的流场。使用沉浸式边界方法（IBM）在我们游泳器边界的边界周围采样了来自神经网络的压力和速度场输出，以准确有效地计算其游泳运动。我们证明了混合模拟器在2D Carangiform游泳器上的计算效率和可不同性。由于可怜性，该模拟器可用于通过基于直接梯度的优化浸入流体中的软体体系的控件设计。

Accurate simulation of soft mechanisms under dynamic actuation is critical for the design of soft robots. We address this gap with our differentiable simulation tool by learning the material parameters of our soft robotic fish. On the example of a soft robotic fish, we demonstrate an experimentally-verified, fast optimization pipeline for learning the material parameters from quasi-static data via differentiable simulation and apply it to the prediction of dynamic performance. Our method identifies physically plausible Young's moduli for various soft silicone elastomers and stiff acetal copolymers used in creation of our three different robotic fish tail designs. We show that our method is compatible with varying internal geometry of the actuators, such as the number of hollow cavities. Our framework allows high fidelity prediction of dynamic behavior for composite bi-morph bending structures in real hardware to millimeter-accuracy and within 3 percent error normalized to actuator length. We provide a differentiable and robust estimate of the thrust force using a neural network thrust predictor; this estimate allows for accurate modeling of our experimental setup measuring bollard pull. This work presents a prototypical hardware and simulation problem solved using our differentiable framework; the framework can be applied to higher dimensional parameter inference, learning control policies, and computational design due to its differentiable character.

Previous work has shown the potential of deep learning to predict renal obstruction using kidney ultrasound images. However, these image-based classifiers have been trained with the goal of single-visit inference in mind. We compare methods from video action recognition (i.e. convolutional pooling, LSTM, TSM) to adapt single-visit convolutional models to handle multiple visit inference. We demonstrate that incorporating images from a patient's past hospital visits provides only a small benefit for the prediction of obstructive hydronephrosis. Therefore, inclusion of prior ultrasounds is beneficial, but prediction based on the latest ultrasound is sufficient for patient risk stratification.

Facial analysis systems have been deployed by large companies and critiqued by scholars and activists for the past decade. Many existing algorithmic audits examine the performance of these systems on later stage elements of facial analysis systems like facial recognition and age, emotion, or perceived gender prediction; however, a core component to these systems has been vastly understudied from a fairness perspective: face detection, sometimes called face localization. Since face detection is a pre-requisite step in facial analysis systems, the bias we observe in face detection will flow downstream to the other components like facial recognition and emotion prediction. Additionally, no prior work has focused on the robustness of these systems under various perturbations and corruptions, which leaves open the question of how various people are impacted by these phenomena. We present the first of its kind detailed benchmark of face detection systems, specifically examining the robustness to noise of commercial and academic models. We use both standard and recently released academic facial datasets to quantitatively analyze trends in face detection robustness. Across all the datasets and systems, we generally find that photos of individuals who are $\textit{masculine presenting}$, $\textit{older}$, of $\textit{darker skin type}$, or have $\textit{dim lighting}$ are more susceptible to errors than their counterparts in other identities.

Multi-agent artificial intelligence research promises a path to develop intelligent technologies that are more human-like and more human-compatible than those produced by "solipsistic" approaches, which do not consider interactions between agents. Melting Pot is a research tool developed to facilitate work on multi-agent artificial intelligence, and provides an evaluation protocol that measures generalization to novel social partners in a set of canonical test scenarios. Each scenario pairs a physical environment (a "substrate") with a reference set of co-players (a "background population"), to create a social situation with substantial interdependence between the individuals involved. For instance, some scenarios were inspired by institutional-economics-based accounts of natural resource management and public-good-provision dilemmas. Others were inspired by considerations from evolutionary biology, game theory, and artificial life. Melting Pot aims to cover a maximally diverse set of interdependencies and incentives. It includes the commonly-studied extreme cases of perfectly-competitive (zero-sum) motivations and perfectly-cooperative (shared-reward) motivations, but does not stop with them. As in real-life, a clear majority of scenarios in Melting Pot have mixed incentives. They are neither purely competitive nor purely cooperative and thus demand successful agents be able to navigate the resulting ambiguity. Here we describe Melting Pot 2.0, which revises and expands on Melting Pot. We also introduce support for scenarios with asymmetric roles, and explain how to integrate them into the evaluation protocol. This report also contains: (1) details of all substrates and scenarios; (2) a complete description of all baseline algorithms and results. Our intention is for it to serve as a reference for researchers using Melting Pot 2.0.

安全的数字无线通信水下已成为一个关键问题，因为海上运营转向采用机器人资产的异质组合，并且随着数字系统的安全性在所有领域都受到挑战。同时，水下信号编码和物理层选项的增殖提供了更大的带宽和灵活性，但主要没有互操作性所需的标准。我们在这里解决了对安全的基本要求，即对资产身份的确认也称为身份验证。我们建议，实施，验证和验证基于第一个数字水下通信标准的身份验证协议。我们的计划主要适用于在海上石油和天然气设施周围运行的AUV，也适用于将来可能还具有声学调制解调器的其他水下设备。它使包括命令和控制在内的沟通更加安全，并为开发更复杂的安全机制提供了基础。

磁共振光谱成像（MRSI）是量化体内代谢物的必不可少的工具，但是低空间分辨率限制了其临床应用。基于深度学习的超分辨率方法为改善MRSI的空间分辨率提供了有希望的结果，但是与实验获得的高分辨率图像相比，超级分辨图像通常是模糊的。已经使用生成对抗网络进行了尝试，以提高图像视觉质量。在这项工作中，我们考虑了另一种类型的生成模型，即基于流的模型，与对抗网络相比，训练更稳定和可解释。具体而言，我们提出了一个基于流动的增强器网络，以提高超分辨率MRSI的视觉质量。与以前的基于流的模型不同，我们的增强器网络包含了来自其他图像模式（MRI）的解剖信息，并使用可学习的基础分布。此外，我们施加指南丢失和数据一致性丢失，以鼓励网络在保持高忠诚度的同时以高视觉质量生成图像。从25名高级神经胶质瘤患者获得的1H-MRSI数据集上进行的实验表明，我们的增强子网络的表现优于对抗网络和基线基线方法。我们的方法还允许视觉质量调整和不确定性估计。

队列研究越来越多地使用加速度计进行体育活动和久坐行为估计。这些设备往往比自我报告易于错误，可以全天捕获活动，并且是经济的。但是，在自由生活的情况下和受试者对象变化下，基于髋关节wor的数据估算久坐行为的先前方法通常是无效的或次优的。在本文中，我们提出了一个本地马尔可夫切换模型，该模型考虑了这种情况，并引入了一种姿势分类和久坐行为分析的一般程序，该程序自然适合该模型。我们的方法在时间序列中具有更改点检测方法，也是一个两个阶段分类步骤，将数据标记为3类（坐着，站立，步进）。通过严格的训练测试范例，我们表明我们的方法达到了80％的精度。此外，我们的方法是强大的，易于解释。

非对比度CT（NCCT）图像中准确的梗塞分割是迈向计算机辅助急性缺血性中风（AIS）评估的关键步骤。在临床实践中，脑半球的双侧对称比较通常用于定位病理异常。最近的研究探索了不对称的协助AIS分割。但是，在评估其对AIS的贡献时，大多数以前基于对称性的工作都混合了不同类型的不对称性。在本文中，我们提出了一个新型的不对称分解网络（ADN），以自动将NCCT中的病理不对称性和内在的解剖不对称分离，以进行更有效和可解释的AIS分割。 ADN首先基于输入NCCT进行不对称分解，该输入nccts产生不同类型的3D不对称图。然后生成合成的，固有的 - 敏化补偿和病理 - 空气 - 对称盐的NCCT体积，后来用作分割网络的输入。 ADN的培训结合了领域知识，并采用了组织型意识到的正则化损失函数，以鼓励临床上敏感的病理不对称提取。加上无监督的3D转换网络，ADN在公共NCCT数据集上实现了最新的AIS分割性能。除了出色的表现外，我们认为学到的临床可解剖的不对称图也可以为更好地理解AIS评估提供见解。我们的代码可从https://github.com/nihaomiao/miccai22_adn获得。

从历史上看，患者数据集已用于开发和验证PET/MRI和PET/CT的各种重建算法。为了使这种算法开发，无需获得数百个患者检查，在本文中，我们展示了一种深度学习技术，可以从丰富的全身MRI中产生合成但逼真的全身宠物纹状体。具体来说，我们使用56 $^{18} $ F-FDG-PET/MRI考试的数据集训练3D残差UNET来预测全身T1加权MRI的生理PET摄取。在训练中，我们实施了平衡的损失函数，以在较大的动态范围内产生逼真的吸收，并沿着层析成像线的响应线对模仿宠物的获取产生计算的损失。预测的PET图像预计会产生合成宠物飞行时间（TOF）正式图，可与供应商提供的PET重建算法一起使用，包括使用基于CT的衰减校正（CTAC）和基于MR的衰减校正（MRAC（MRAC） ）。由此产生的合成数据概括了生理学$^{18} $ f-fdg摄取，例如高摄取量位于大脑和膀胱，以及肝脏，肾脏，心脏和肌肉的吸收。为了模拟高摄取的异常，我们还插入合成病变。我们证明，该合成PET数据可以与实际PET数据互换使用，用于比较CT和基于MR的衰减校正方法的PET量化任务，与使用真实数据相比，在平均值中实现了$ \ leq 7.6 \％$误差。这些结果共同表明，所提出的合成PET数据管道可以合理地用于开发，评估和验证PET/MRI重建方法。