异常气道扩张,称为牵引支气管扩张,是特发性肺纤维化(IPF)的典型特征。体积计算断层扫描(CT)成像捕获IPF中逐渐变细的丢失。我们假设气道异常的自动化量化可以提供IPF疾病程度和严重程度的估算。我们提出了一种自动化计算管道,系统地将气道树木从基于深度学习的气道分割中划分到其裂片和世代分支,从而从胸部CT获得气道结构措施。重要的是,透气阻止通过厚波传播的杂散气道分支的发生,并通过图表搜索去除气道树中的环,克服现有气道骨架算法的限制。在14名健康参与者和14名IPF患者之间比较了透气段(跨空间)和透气曲线曲线之间的逐渐变化。 IPF患者中,Airway interberering显着降低,与健康对照相比,Airway曲线曲调显着增加。差异在下叶中最大标记,符合IPF相关损伤的典型分布。透气是一种开源管道,避免了现有的气道定量算法的限制,并具有临床解释性。自动化气道测量可能具有作为IPF严重程度和疾病程度的新型成像生物标志物。
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受数据驱动的超材料设计的启发,该设计范围已成为一种引人注目的范式,可以释放多尺度体系结构的潜力。然而,以模型为中心的研究趋势缺乏专门用于数据获取的原则性框架,其质量传播到下游任务。通常是由天真的空间填充设计在形状描述符空间中建造的,具有高度不平衡或与感兴趣的设计任务相矛盾的属性分布。为此,我们提出了T-Metaset:一个基于积极学习的数据采集框架,旨在指导多样化和任务感知的数据生成。显然,我们在数据驱动的超材料设计的早期阶段寻求解决方案,但经常被忽视的场景:当已经准备了一个纯属性(〜O(10^4))纯形状的库时,没有评估属性。关键的想法是利用从生成模型中学到的数据驱动的形状描述符,适合稀疏回归器作为启动代理商,并利用与多样性相关的指标,以将数据获取推向帮助设计师实现设计目标的领域。我们在三种部署案例中验证了所提出的框架,其中包括一般使用,特定于任务的使用和可量身定制的使用。两个大规模的机械超材料数据集用于证明功效。 T-Metaset适用于基于图像的一般设计表示,可以提高数据驱动设计的未来进步。
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贝叶斯网络(BN)的图形结构可以使用众所周知的得分和搜索方法从数据中学习。先前的工作表明,将条件概率分布(CPD)的结构化表示形式纳入得分和搜索方法可以提高学习图的准确性。在本文中,我们提出了一种能够学习BN图的新方法,并同时建模变量之间的线性和非线性局部概率关系。我们通过功能选择的组合来实现这一目标,以减少本地关系的搜索空间,并扩展得分和搜索方法,以将CPD模型纳入变量,作为多元自适应回归条纹(MARS)。火星是代表分段样条函数的多项式回归模型。我们在一组离散和连续的基准实例上显示,我们提出的方法可以提高学习图的准确性,同时扩展大量变量的实例。
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Modeling lies at the core of both the financial and the insurance industry for a wide variety of tasks. The rise and development of machine learning and deep learning models have created many opportunities to improve our modeling toolbox. Breakthroughs in these fields often come with the requirement of large amounts of data. Such large datasets are often not publicly available in finance and insurance, mainly due to privacy and ethics concerns. This lack of data is currently one of the main hurdles in developing better models. One possible option to alleviating this issue is generative modeling. Generative models are capable of simulating fake but realistic-looking data, also referred to as synthetic data, that can be shared more freely. Generative Adversarial Networks (GANs) is such a model that increases our capacity to fit very high-dimensional distributions of data. While research on GANs is an active topic in fields like computer vision, they have found limited adoption within the human sciences, like economics and insurance. Reason for this is that in these fields, most questions are inherently about identification of causal effects, while to this day neural networks, which are at the center of the GAN framework, focus mostly on high-dimensional correlations. In this paper we study the causal preservation capabilities of GANs and whether the produced synthetic data can reliably be used to answer causal questions. This is done by performing causal analyses on the synthetic data, produced by a GAN, with increasingly more lenient assumptions. We consider the cross-sectional case, the time series case and the case with a complete structural model. It is shown that in the simple cross-sectional scenario where correlation equals causation the GAN preserves causality, but that challenges arise for more advanced analyses.
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We present the interpretable meta neural ordinary differential equation (iMODE) method to rapidly learn generalizable (i.e., not parameter-specific) dynamics from trajectories of multiple dynamical systems that vary in their physical parameters. The iMODE method learns meta-knowledge, the functional variations of the force field of dynamical system instances without knowing the physical parameters, by adopting a bi-level optimization framework: an outer level capturing the common force field form among studied dynamical system instances and an inner level adapting to individual system instances. A priori physical knowledge can be conveniently embedded in the neural network architecture as inductive bias, such as conservative force field and Euclidean symmetry. With the learned meta-knowledge, iMODE can model an unseen system within seconds, and inversely reveal knowledge on the physical parameters of a system, or as a Neural Gauge to "measure" the physical parameters of an unseen system with observed trajectories. We test the validity of the iMODE method on bistable, double pendulum, Van der Pol, Slinky, and reaction-diffusion systems.
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We propose Hierarchical ProtoPNet: an interpretable network that explains its reasoning process by considering the hierarchical relationship between classes. Different from previous methods that explain their reasoning process by dissecting the input image and finding the prototypical parts responsible for the classification, we propose to explain the reasoning process for video action classification by dissecting the input video frames on multiple levels of the class hierarchy. The explanations leverage the hierarchy to deal with uncertainty, akin to human reasoning: When we observe water and human activity, but no definitive action it can be recognized as the water sports parent class. Only after observing a person swimming can we definitively refine it to the swimming action. Experiments on ActivityNet and UCF-101 show performance improvements while providing multi-level explanations.
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Artificial intelligence (AI) in the form of deep learning bears promise for drug discovery and chemical biology, $\textit{e.g.}$, to predict protein structure and molecular bioactivity, plan organic synthesis, and design molecules $\textit{de novo}$. While most of the deep learning efforts in drug discovery have focused on ligand-based approaches, structure-based drug discovery has the potential to tackle unsolved challenges, such as affinity prediction for unexplored protein targets, binding-mechanism elucidation, and the rationalization of related chemical kinetic properties. Advances in deep learning methodologies and the availability of accurate predictions for protein tertiary structure advocate for a $\textit{renaissance}$ in structure-based approaches for drug discovery guided by AI. This review summarizes the most prominent algorithmic concepts in structure-based deep learning for drug discovery, and forecasts opportunities, applications, and challenges ahead.
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The ability to convert reciprocating, i.e., alternating, actuation into rotary motion using linkages is hindered fundamentally by their poor torque transmission capability around kinematic singularity configurations. Here, we harness the elastic potential energy of a linear spring attached to the coupler link of four-bar mechanisms to manipulate force transmission around the kinematic singularities. We developed a theoretical model to explore the parameter space for proper force transmission in slider-crank and rocker-crank four-bar kinematics. Finally, we verified the proposed model and methodology by building and testing a macro-scale prototype of a slider-crank mechanism. We expect this approach to enable the development of small-scale rotary engines and robotic devices with closed kinematic chains dealing with serial kinematic singularities, such as linkages and parallel manipulators.
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Prevailing methods for assessing and comparing generative AIs incentivize responses that serve a hypothetical representative individual. Evaluating models in these terms presumes homogeneous preferences across the population and engenders selection of agglomerative AIs, which fail to represent the diverse range of interests across individuals. We propose an alternative evaluation method that instead prioritizes inclusive AIs, which provably retain the requisite knowledge not only for subsequent response customization to particular segments of the population but also for utility-maximizing decisions.
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We study the problem of combining neural networks with symbolic reasoning. Recently introduced frameworks for Probabilistic Neurosymbolic Learning (PNL), such as DeepProbLog, perform exponential-time exact inference, limiting the scalability of PNL solutions. We introduce Approximate Neurosymbolic Inference (A-NeSI): a new framework for PNL that uses neural networks for scalable approximate inference. A-NeSI 1) performs approximate inference in polynomial time without changing the semantics of probabilistic logics; 2) is trained using data generated by the background knowledge; 3) can generate symbolic explanations of predictions; and 4) can guarantee the satisfaction of logical constraints at test time, which is vital in safety-critical applications. Our experiments show that A-NeSI is the first end-to-end method to scale the Multi-digit MNISTAdd benchmark to sums of 15 MNIST digits, up from 4 in competing systems. Finally, our experiments show that A-NeSI achieves explainability and safety without a penalty in performance.
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