Course load analytics (CLA) inferred from LMS and enrollment features can offer a more accurate representation of course workload to students than credit hours and potentially aid in their course selection decisions. In this study, we produce and evaluate the first machine-learned predictions of student course load ratings and generalize our model to the full 10,000 course catalog of a large public university. We then retrospectively analyze longitudinal differences in the semester load of student course selections throughout their degree. CLA by semester shows that a student's first semester at the university is among their highest load semesters, as opposed to a credit hour-based analysis, which would indicate it is among their lowest. Investigating what role predicted course load may play in program retention, we find that students who maintain a semester load that is low as measured by credit hours but high as measured by CLA are more likely to leave their program of study. This discrepancy in course load is particularly pertinent in STEM and associated with high prerequisite courses. Our findings have implications for academic advising, institutional handling of the freshman experience, and student-facing analytics to help students better plan, anticipate, and prepare for their selected courses.
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Protein structure prediction is a fundamental problem in computational molecular biology. Classical algorithms such as ab-initio or threading as well as many learning methods have been proposed to solve this challenging problem. However, most reinforcement learning methods tend to model the state-action pairs as discrete objects. In this paper, we develop a reinforcement learning (RL) framework in a continuous setting and based on a stochastic parametrized Hamiltonian version of the Pontryagin maximum principle (PMP) to solve the side-chain packing and protein-folding problem. For special cases our formulation can be reduced to previous work where the optimal folding trajectories are trained using an explicit use of Langevin dynamics. Optimal continuous stochastic Hamiltonian dynamics folding pathways can be derived with use of different models of molecular energetics and force fields. In our RL implementation we adopt a soft actor-critic methodology however we can replace this other RL training based on A2C, A3C or PPO.
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We apply Physics Informed Neural Networks (PINNs) to the problem of wildfire fire-front modelling. The PINN is an approach that integrates a differential equation into the optimisation loss function of a neural network to guide the neural network to learn the physics of a problem. We apply the PINN to the level-set equation, which is a Hamilton-Jacobi partial differential equation that models a fire-front with the zero-level set. This results in a PINN that simulates a fire-front as it propagates through a spatio-temporal domain. We demonstrate the agility of the PINN to learn physical properties of a fire under extreme changes in external conditions (such as wind) and show that this approach encourages continuity of the PINN's solution across time. Furthermore, we demonstrate how data assimilation and uncertainty quantification can be incorporated into the PINN in the wildfire context. This is significant contribution to wildfire modelling as the level-set method -- which is a standard solver to the level-set equation -- does not naturally provide this capability.
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ICECUBE是一种用于检测1 GEV和1 PEV之间大气和天体中微子的光学传感器的立方公斤阵列,该阵列已部署1.45 km至2.45 km的南极的冰盖表面以下1.45 km至2.45 km。来自ICE探测器的事件的分类和重建在ICeCube数据分析中起着核心作用。重建和分类事件是一个挑战,这是由于探测器的几何形状,不均匀的散射和冰中光的吸收,并且低于100 GEV的光,每个事件产生的信号光子数量相对较少。为了应对这一挑战,可以将ICECUBE事件表示为点云图形,并将图形神经网络(GNN)作为分类和重建方法。 GNN能够将中微子事件与宇宙射线背景区分开,对不同的中微子事件类型进行分类,并重建沉积的能量,方向和相互作用顶点。基于仿真,我们提供了1-100 GEV能量范围的比较与当前ICECUBE分析中使用的当前最新最大似然技术,包括已知系统不确定性的影响。对于中微子事件分类,与当前的IceCube方法相比,GNN以固定的假阳性速率(FPR)提高了信号效率的18%。另外,GNN在固定信号效率下将FPR的降低超过8(低于半百分比)。对于能源,方向和相互作用顶点的重建,与当前最大似然技术相比,分辨率平均提高了13%-20%。当在GPU上运行时,GNN能够以几乎是2.7 kHz的中位数ICECUBE触发速率的速率处理ICECUBE事件,这打开了在在线搜索瞬态事件中使用低能量中微子的可能性。
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在二阶不确定的贝叶斯网络中,条件概率仅在分布中已知,即概率上的概率。Delta方法已应用于扩展精确的一阶推理方法,以通过从贝叶斯网络得出的总和产物网络传播均值和方差,从而表征了认知不确定性或模型本身的不确定性。另外,已经证明了Polytrees的二阶信仰传播,但没有针对一般的定向无环形结构。在这项工作中,我们将循环信念传播扩展到二阶贝叶斯网络的设置,从而产生二阶循环信念传播(SOLBP)。对于二阶贝叶斯网络,SOLBP生成了与Sum-Propoduct网络生成的网络一致的推论,同时更加有效且可扩展。
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当历史数据受到限制时,与贝叶斯网络节点相关的条件概率不确定,并且可以在经验上进行估计。二阶估计方法为估计概率和量化这些估计的不确定性提供了一个框架。我们将这些案例称为Uncer Tain或二阶贝叶斯网络。当完成此类数据时,即每个实例化都观察到所有可变值,已知有条件的概率是dirichlet分布的。本文通过使他们能够学习参数(即条件概率),通过不完整的数据来学习不确定的贝叶斯网络的当前最新方法。我们广泛评估各种方法,通过各种查询的置信界的所需和经验得出的强度来学习参数的后验。
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在深度学习研究中,自学学习(SSL)引起了极大的关注,引起了计算机视觉和遥感社区的兴趣。尽管计算机视觉取得了很大的成功,但SSL在地球观测领域的大部分潜力仍然锁定。在本文中,我们对在遥感的背景下为计算机视觉的SSL概念和最新发展提供了介绍,并回顾了SSL中的概念和最新发展。此外,我们在流行的遥感数据集上提供了现代SSL算法的初步基准,从而验证了SSL在遥感中的潜力,并提供了有关数据增强的扩展研究。最后,我们确定了SSL未来研究的有希望的方向的地球观察(SSL4EO),以铺平了两个领域的富有成效的相互作用。
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野火传播的计算模拟通常在各种条件下(例如地形,燃料类型,天气)采用经验分布计算。条件下的小扰动通常会导致火灾传播(例如速度和方向)的显着变化,因此需要进行计算昂贵的大型模拟以量化不确定性。模型仿真寻求使用机器学习的物理模型的替代表示,旨在提供更有效和/或简化的替代模型。我们提出了一个专用时空神经网络,用于模型仿真,能够捕获火灾传播模型的复杂行为。所提出的方法可以在基于神经网络的方法通常具有挑战性的空间和时间分辨率上进行近似预测。此外,由于新的数据增强方法,即使使用小型训练集,提出的方法也是可靠的。经验实验表明,模拟和模拟的火山之间的良好一致性,平均Jaccard得分为0.76。
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我们介绍并评估了一种弱监督的方法,以基于远程感知的数据和接近零的人类相互作用来量化城市森林的时空分布。成功训练语义细分的机器学习模型通常取决于高质量标签的可用性。我们评估高分辨率,三维点云数据(LIDAR)作为嘈杂标签的来源的好处,以便训练模型以在正吞原中的定位。作为概念证明,我们感觉到桑迪飓风对纽约市康尼岛(NYC)的城市森林的影响,并将其引用到纽约布鲁克林的影响较小的城市空间。
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自欺欺人的学习(SSL)由于能够学习任务不足的表示而没有人类注释的能力,因此对遥感和地球观察引起了极大的兴趣。尽管大多数现有的SSL在遥感中起作用,利用Convnet骨架并专注于单个模态,但我们探索了视觉变压器(VIT)的潜在,用于关节SAR-OCTICATION学习。基于Dino,一种最先进的SSL算法,它从输入图像的两个增强视图中提取知识,我们通过将所有通道串联到统一输入来结合SAR和光学图像。随后,我们随机掩盖了一种模式作为数据增强策略的通道。在训练期间,该模型将被喂养仅光学,仅SAR-SAR-SAR-SAR-OFICATION图像对学习内部和模式内表示。使用BigeArthnet-MM数据集的实验结果证明了VIT骨架和拟议的多模式SSL算法Dino-MM的好处。
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