在基于模型的医学图像分析中,感兴趣的三个特征是感兴趣的结构,其相对姿势和代表一些物理性质的图像强度谱的形状。通常,这些通过统计模型分别通过统计模型来通过主要测地分析或主成分分析将对象的特征分解成一组基函数。本研究提出了一种统计建模方法,用于在医学图像中自动学习形状,姿势和强度特征,我们称之为动态多特征类高斯过程模型(DMFC-GPM)。 DMFC-GPM是基于高斯过程(GP)的模型,具有编码线性和非线性变化的共享潜在空间。我们的方法在连续域中定义,其具有基于变形字段的线性空间中的形状,姿势和强度特征类。在用于建模形状和强度特征变化的方法以及比较刚性变换(姿势)的方法中,适于变形现场度量。此外,DMFC-GPMS继承了GPS内在的属性,包括边缘化和回归。此外,它们允许在从图像采集过程获得的那些之上增加额外的姿势特征可变性;我们是什么术语作为排列建模。对于使用DMFC-GPMS的图像分析任务,我们适应了Metropolis-Hastings算法,使得具有完全概率的特征预测。我们验证了使用受控合成数据的方法,并且我们在肩部的CT图像上对骨结构进行实验,以说明模型姿势和形状特征预测的功效。模型性能结果表明,这种新的造型范例是强大,准确,可访问的,并且具有潜在的应用,包括肌肉骨骼障碍和临床决策
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开普勒和苔丝任务产生了超过100,000个潜在的传输信号,必须处理,以便创建行星候选的目录。在过去几年中,使用机器学习越来越感兴趣,以分析这些数据以寻找新的外延网。与现有的机器学习作品不同,exoMiner,建议的深度学习分类器在这项工作中,模仿域专家如何检查诊断测试以VET传输信号。 exoMiner是一种高度准确,可说明的和强大的分类器,其中1)允许我们验证来自桅杆开口存档的301个新的外延网,而2)是足够的,足以应用于诸如正在进行的苔丝任务的任务中应用。我们进行了广泛的实验研究,以验证exoMiner在不同分类和排名指标方面比现有的传输信号分类器更可靠,准确。例如,对于固定精度值为99%,exoMiner检索测试集中的93.6%的所有外产网(即,召回= 0.936),而最佳现有分类器的速率为76.3%。此外,exoMiner的模块化设计有利于其解释性。我们介绍了一个简单的解释性框架,提供了具有反馈的专家,为什么exoMiner将运输信号分类为特定类标签(例如,行星候选人或不是行星候选人)。
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我们研究了点击流行为中预测在线课程中学生知识获取的问题。通过电子学习讲座交付的激增,我们专注于讲座视频中的学生在视频活动中,由内容和视频测验组成。我们预测视频测验性能的方法基于我们开发的三个关键思路。首先,我们通过在原始事件数据上运行的时间序列学习架构模拟学生的点击行为,而不是定义可能在现有方法中定义手工制作的功能,可能丢失在单击序列内的重要信息。其次,我们开发了一个自我监督的Clickstream预培训,以学习Clickstream事件的信息表示,可以有效地初始化预测模型。第三,我们提出了一种基于聚类的基于元学习的培训,可以优化预测模型,以利用学生点击流序列中的频繁模式集群。通过对三个现实世界数据集的实验,我们证明我们的方法在预测学生的视频测验性能方面的两个基线模型中获得了大量改进。此外,我们通过消融研究验证了我们框架的预培训和元学习组成部分的重要性。最后,我们展示了我们的方法论如何了解与有用的学习分析有用的知识获取相关的视频监视行为的见解。
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Designing experiments often requires balancing between learning about the true treatment effects and earning from allocating more samples to the superior treatment. While optimal algorithms for the Multi-Armed Bandit Problem (MABP) provide allocation policies that optimally balance learning and earning, they tend to be computationally expensive. The Gittins Index (GI) is a solution to the MABP that can simultaneously attain optimality and computationally efficiency goals, and it has been recently used in experiments with Bernoulli and Gaussian rewards. For the first time, we present a modification of the GI rule that can be used in experiments with exponentially-distributed rewards. We report its performance in simulated 2- armed and 3-armed experiments. Compared to traditional non-adaptive designs, our novel GI modified design shows operating characteristics comparable in learning (e.g. statistical power) but substantially better in earning (e.g. direct benefits). This illustrates the potential that designs using a GI approach to allocate participants have to improve participant benefits, increase efficiencies, and reduce experimental costs in adaptive multi-armed experiments with exponential rewards.
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Quadruped robots are currently used in industrial robotics as mechanical aid to automate several routine tasks. However, presently, the usage of such a robot in a domestic setting is still very much a part of the research. This paper discusses the understanding and virtual simulation of such a robot capable of detecting and understanding human emotions, generating its gait, and responding via sounds and expression on a screen. To this end, we use a combination of reinforcement learning and software engineering concepts to simulate a quadruped robot that can understand emotions, navigate through various terrains and detect sound sources, and respond to emotions using audio-visual feedback. This paper aims to establish the framework of simulating a quadruped robot that is emotionally intelligent and can primarily respond to audio-visual stimuli using motor or audio response. The emotion detection from the speech was not as performant as ERANNs or Zeta Policy learning, still managing an accuracy of 63.5%. The video emotion detection system produced results that are almost at par with the state of the art, with an accuracy of 99.66%. Due to its "on-policy" learning process, the PPO algorithm was extremely rapid to learn, allowing the simulated dog to demonstrate a remarkably seamless gait across the different cadences and variations. This enabled the quadruped robot to respond to generated stimuli, allowing us to conclude that it functions as predicted and satisfies the aim of this work.
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Real-world robotic grasping can be done robustly if a complete 3D Point Cloud Data (PCD) of an object is available. However, in practice, PCDs are often incomplete when objects are viewed from few and sparse viewpoints before the grasping action, leading to the generation of wrong or inaccurate grasp poses. We propose a novel grasping strategy, named 3DSGrasp, that predicts the missing geometry from the partial PCD to produce reliable grasp poses. Our proposed PCD completion network is a Transformer-based encoder-decoder network with an Offset-Attention layer. Our network is inherently invariant to the object pose and point's permutation, which generates PCDs that are geometrically consistent and completed properly. Experiments on a wide range of partial PCD show that 3DSGrasp outperforms the best state-of-the-art method on PCD completion tasks and largely improves the grasping success rate in real-world scenarios. The code and dataset will be made available upon acceptance.
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When robots learn reward functions using high capacity models that take raw state directly as input, they need to both learn a representation for what matters in the task -- the task ``features" -- as well as how to combine these features into a single objective. If they try to do both at once from input designed to teach the full reward function, it is easy to end up with a representation that contains spurious correlations in the data, which fails to generalize to new settings. Instead, our ultimate goal is to enable robots to identify and isolate the causal features that people actually care about and use when they represent states and behavior. Our idea is that we can tune into this representation by asking users what behaviors they consider similar: behaviors will be similar if the features that matter are similar, even if low-level behavior is different; conversely, behaviors will be different if even one of the features that matter differs. This, in turn, is what enables the robot to disambiguate between what needs to go into the representation versus what is spurious, as well as what aspects of behavior can be compressed together versus not. The notion of learning representations based on similarity has a nice parallel in contrastive learning, a self-supervised representation learning technique that maps visually similar data points to similar embeddings, where similarity is defined by a designer through data augmentation heuristics. By contrast, in order to learn the representations that people use, so we can learn their preferences and objectives, we use their definition of similarity. In simulation as well as in a user study, we show that learning through such similarity queries leads to representations that, while far from perfect, are indeed more generalizable than self-supervised and task-input alternatives.
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and widely used information measurement metric, particularly popularized for SSVEP- based Brain-Computer (BCI) interfaces. By combining speed and accuracy into a single-valued parameter, this metric aids in the evaluation and comparison of various target identification algorithms across different BCI communities. To accurately depict performance and inspire an end-to-end design for futuristic BCI designs, a more thorough examination and definition of ITR is therefore required. We model the symbiotic communication medium, hosted by the retinogeniculate visual pathway, as a discrete memoryless channel and use the modified capacity expressions to redefine the ITR. We use graph theory to characterize the relationship between the asymmetry of the transition statistics and the ITR gain with the new definition, leading to potential bounds on data rate performance. On two well-known SSVEP datasets, we compared two cutting-edge target identification methods. Results indicate that the induced DM channel asymmetry has a greater impact on the actual perceived ITR than the change in input distribution. Moreover, it is demonstrated that the ITR gain under the new definition is inversely correlated with the asymmetry in the channel transition statistics. Individual input customizations are further shown to yield perceived ITR performance improvements. An algorithm is proposed to find the capacity of binary classification and further discussions are given to extend such results to ensemble techniques.We anticipate that the results of our study will contribute to the characterization of the highly dynamic BCI channel capacities, performance thresholds, and improved BCI stimulus designs for a tighter symbiosis between the human brain and computer systems while enhancing the efficiency of the underlying communication resources.
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A step-search sequential quadratic programming method is proposed for solving nonlinear equality constrained stochastic optimization problems. It is assumed that constraint function values and derivatives are available, but only stochastic approximations of the objective function and its associated derivatives can be computed via inexact probabilistic zeroth- and first-order oracles. Under reasonable assumptions, a high-probability bound on the iteration complexity of the algorithm to approximate first-order stationarity is derived. Numerical results on standard nonlinear optimization test problems illustrate the advantages and limitations of our proposed method.
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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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