我们对跨越各个领域的多种域的275个经验网络的随机块模型(SBM)的拟合质量和尺寸幅度的订单进行系统分析。我们采用后预测模型检查作为评估拟合质量的标准,这涉及根据一组网络描述符比较由经验网络的推断模型生成的网络。我们观察到SBM能够为大多数网络提供准确的描述,但缺乏所有建模要求。特别地,具有大直径和慢速混合随机步道的网络往往由SBM非常赘言。然而,与经常假设的相反,在许多情况下,SBM可以很好地描述具有高丰度三角形的网络。我们证明,简单的网络描述符可用于评估SBM是否可以提供足够准确的表示,可能指向可以系统地提高这类模型的表现力的可能模型扩展。
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社区检测是网络科学中最重要的方法领域之一,在过去的几十年里引起了大量关注的方法之一。该区域处理网络的自动部门到基础构建块中,目的是提供其大规模结构的概要。尽管它的重要性和广泛的采用普及,所谓的最先进和实际在各种领域实际使用的方法之间存在明显的差距。在这里,我们试图通过根据是否具有“描述性”或“推论”目标来划分现有方法来解决这种差异。虽然描述性方法在基于社区结构的直观概念的网络中找到模式的模式,但是推理方法阐述了精确的生成模型,并尝试将其符合数据。通过这种方式,他们能够为网络形成机制提供见解,并以统计证据支持的方式与随机性的单独结构。我们审查如何使用推论目标采用描述性方法被陷入困境和误导性答案,因此应该一般而言。我们认为推理方法更通常与更清晰的科学问题一致,产生更强大的结果,并且应该是一般的首选。我们试图消除一些神话和半真半假在实践中使用社区检测时,努力改善这些方法的使用以及对结果的解释。
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网络慷慨地,相似节点的趋势和传递性,连接两个节点的趋势如果它们共享公共邻居,则在网络分析中被混为特性,因为一个机制可以驱动另一个机制。在这里,我们提出了一种能够区分两个机制的生成模型和相应的推理过程。我们的方法基于随机块模型(SBM)的变化,增加了三合一封闭边缘,其推断可以识别负责网络中每个边缘存在的最合理的机制,以及基础社区结构本身。我们展示该方法如何避免通过网络中的三角形形成的单独引起的虚假社区的检测,以及它在与没有三合会的纯版本的纯版本相比,如何提高边缘预测的性能。
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我们将图形神经网络训练来自小工具N体模拟的光晕目录的神经网络,以执行宇宙学参数的无现场级别可能的推断。目录包含$ \ Lessim $ 5,000 HAROS带质量$ \ gtrsim 10^{10} 〜h^{ - 1} m_ \ odot $,定期卷为$(25〜H^{ - 1} {\ rm mpc}){\ rm mpc}) ^3 $;目录中的每个光环都具有多种特性,例如位置,质量,速度,浓度和最大圆速度。我们的模型构建为置换,翻译和旋转的不变性,不施加最低限度的规模来提取信息,并能够以平均值来推断$ \ omega _ {\ rm m} $和$ \ sigma_8 $的值$ \ sim6 \%$的相对误差分别使用位置加上速度和位置加上质量。更重要的是,我们发现我们的模型非常强大:他们可以推断出使用数千个N-n-Body模拟的Halo目录进行测试时,使用五个不同的N-进行测试时,在使用Halo目录进行测试时,$ \ omega _ {\ rm m} $和$ \ sigma_8 $身体代码:算盘,Cubep $^3 $ M,Enzo,PKDGrav3和Ramses。令人惊讶的是,经过培训的模型推断$ \ omega _ {\ rm m} $在对数千个最先进的骆驼水力动力模拟进行测试时也可以使用,该模拟使用四个不同的代码和子网格物理实现。使用诸如浓度和最大循环速度之类的光环特性允许我们的模型提取更多信息,而牺牲了模型的鲁棒性。这可能会发生,因为不同的N体代码不会在与这些参数相对应的相关尺度上收敛。
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社会机器人的快速发展刺激了人类运动建模,解释和预测,主动碰撞,人类机器人相互作用和共享空间中共同损害的积极研究。现代方法的目标需要高质量的数据集进行培训和评估。但是,大多数可用数据集都遭受了不准确的跟踪数据或跟踪人员的不自然的脚本行为。本文试图通过在语义丰富的环境中提供运动捕获,眼睛凝视跟踪器和板载机器人传感器的高质量跟踪信息来填补这一空白。为了诱导记录参与者的自然行为,我们利用了松散的脚本化任务分配,这使参与者以自然而有目的的方式导航到动态的实验室环境。本文介绍的运动数据集设置了高质量的标准,因为使用语义信息可以增强现实和准确的数据,从而使新算法的开发不仅依赖于跟踪信息,而且还依赖于移动代理的上下文提示,还依赖于跟踪信息。静态和动态环境。
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监视自动实时流处理系统的行为已成为现实世界应用中最相关的问题之一。这种系统的复杂性已在很大程度上依赖于高维输入数据和数据饥饿的机器学习(ML)算法。我们提出了一个灵活的系统,功能监视(FM),该系统在此类数据集中检测数据漂移,并具有较小且恒定的内存足迹和流应用程序中的小计算成本。该方法基于多变量统计测试,并且是由设计驱动的数据(从数据中估算了完整的参考分布)。它监视系统使用的所有功能,同时每当发生警报时提供可解释的功能排名(以帮助根本原因分析)。系统的计算和记忆轻度是由于使用指数移动直方图而导致的。在我们的实验研究中,我们用其参数分析了系统的行为,更重要的是显示了它检测到与单个特征无直接相关的问题的示例。这说明了FM如何消除添加自定义信号以检测特定类型问题的需求,并且监视功能可用空间通常足够。
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Accurate determination of a small molecule candidate (ligand) binding pose in its target protein pocket is important for computer-aided drug discovery. Typical rigid-body docking methods ignore the pocket flexibility of protein, while the more accurate pose generation using molecular dynamics is hindered by slow protein dynamics. We develop a tiered tensor transform (3T) algorithm to rapidly generate diverse protein-ligand complex conformations for both pose and affinity estimation in drug screening, requiring neither machine learning training nor lengthy dynamics computation, while maintaining both coarse-grain-like coordinated protein dynamics and atomistic-level details of the complex pocket. The 3T conformation structures we generate are closer to experimental co-crystal structures than those generated by docking software, and more importantly achieve significantly higher accuracy in active ligand classification than traditional ensemble docking using hundreds of experimental protein conformations. 3T structure transformation is decoupled from the system physics, making future usage in other computational scientific domains possible.
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Variational autoencoders model high-dimensional data by positing low-dimensional latent variables that are mapped through a flexible distribution parametrized by a neural network. Unfortunately, variational autoencoders often suffer from posterior collapse: the posterior of the latent variables is equal to its prior, rendering the variational autoencoder useless as a means to produce meaningful representations. Existing approaches to posterior collapse often attribute it to the use of neural networks or optimization issues due to variational approximation. In this paper, we consider posterior collapse as a problem of latent variable non-identifiability. We prove that the posterior collapses if and only if the latent variables are non-identifiable in the generative model. This fact implies that posterior collapse is not a phenomenon specific to the use of flexible distributions or approximate inference. Rather, it can occur in classical probabilistic models even with exact inference, which we also demonstrate. Based on these results, we propose a class of latent-identifiable variational autoencoders, deep generative models which enforce identifiability without sacrificing flexibility. This model class resolves the problem of latent variable non-identifiability by leveraging bijective Brenier maps and parameterizing them with input convex neural networks, without special variational inference objectives or optimization tricks. Across synthetic and real datasets, latent-identifiable variational autoencoders outperform existing methods in mitigating posterior collapse and providing meaningful representations of the data.
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Differentiable Architecture Search (DARTS) has attracted considerable attention as a gradient-based Neural Architecture Search (NAS) method. Since the introduction of DARTS, there has been little work done on adapting the action space based on state-of-art architecture design principles for CNNs. In this work, we aim to address this gap by incrementally augmenting the DARTS search space with micro-design changes inspired by ConvNeXt and studying the trade-off between accuracy, evaluation layer count, and computational cost. To this end, we introduce the Pseudo-Inverted Bottleneck conv block intending to reduce the computational footprint of the inverted bottleneck block proposed in ConvNeXt. Our proposed architecture is much less sensitive to evaluation layer count and outperforms a DARTS network with similar size significantly, at layer counts as small as 2. Furthermore, with less layers, not only does it achieve higher accuracy with lower GMACs and parameter count, GradCAM comparisons show that our network is able to better detect distinctive features of target objects compared to DARTS.
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Landing an unmanned aerial vehicle unmanned aerial vehicle (UAV) on top of an unmanned surface vehicle (USV) in harsh open waters is a challenging problem, owing to forces that can damage the UAV due to a severe roll and/or pitch angle of the USV during touchdown. To tackle this, we propose a novel model predictive control (MPC) approach enabling a UAV to land autonomously on a USV in these harsh conditions. The MPC employs a novel objective function and an online decomposition of the oscillatory motion of the vessel to predict, attempt, and accomplish the landing during near-zero tilt of the landing platform. The nonlinear prediction of the motion of the vessel is performed using visual data from an onboard camera. Therefore, the system does not require any communication with the USV or a control station. The proposed method was analyzed in numerous robotics simulations in harsh and extreme conditions and further validated in various real-world scenarios.
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