Tabular biomedical data is often high-dimensional but with a very small number of samples. Although recent work showed that well-regularised simple neural networks could outperform more sophisticated architectures on tabular data, they are still prone to overfitting on tiny datasets with many potentially irrelevant features. To combat these issues, we propose Weight Predictor Network with Feature Selection (WPFS) for learning neural networks from high-dimensional and small sample data by reducing the number of learnable parameters and simultaneously performing feature selection. In addition to the classification network, WPFS uses two small auxiliary networks that together output the weights of the first layer of the classification model. We evaluate on nine real-world biomedical datasets and demonstrate that WPFS outperforms other standard as well as more recent methods typically applied to tabular data. Furthermore, we investigate the proposed feature selection mechanism and show that it improves performance while providing useful insights into the learning task.
translated by 谷歌翻译
Genome-wide studies leveraging recent high-throughput sequencing technologies collect high-dimensional data. However, they usually include small cohorts of patients, and the resulting tabular datasets suffer from the "curse of dimensionality". Training neural networks on such datasets is typically unstable, and the models overfit. One problem is that modern weight initialisation strategies make simplistic assumptions unsuitable for small-size datasets. We propose Graph-Conditioned MLP, a novel method to introduce priors on the parameters of an MLP. Instead of randomly initialising the first layer, we condition it directly on the training data. More specifically, we create a graph for each feature in the dataset (e.g., a gene), where each node represents a sample from the same dataset (e.g., a patient). We then use Graph Neural Networks (GNNs) to learn embeddings from these graphs and use the embeddings to initialise the MLP's parameters. Our approach opens the prospect of introducing additional biological knowledge when constructing the graphs. We present early results on 7 classification tasks from gene expression data and show that GC-MLP outperforms an MLP.
translated by 谷歌翻译
大脑区域之间的功能连通性（FC）通常是通过应用于功能磁共振成像（FMRI）数据的统计依赖度量来估计的。所得的功能连接矩阵（FCM）通常用于表示脑图的邻接矩阵。最近，图形神经网络（GNN）已成功应用于FCM，以学习脑图表示。但是，现有GNN方法的一个普遍局限性是，它们要求在模型训练之前知道图形邻接矩阵。因此，隐含地假设数据的基础依赖性结构已知。不幸的是，对于fMRI而言，情况并非如此，因为哪种统计度量的选择最能代表数据的依赖性结构是非平凡的。同样，大多数GNN应用于功能磁共振成像，FC都会随着时间的推移而静态，这与神经科学的证据相反，表明功能性脑网络是随时间变化且动态的。这些复合问题可能会对GNN学习脑图表示的能力产生不利影响。作为解决方案，我们提出了动态大脑图结构学习（DBGSL），这是一种学习fMRI数据最佳时变依赖性结构的监督方法。具体而言，DBGSL通过应用于大脑区域嵌入的时空注意力从fMRI时间表中学习了动态图。然后将所得的图馈送到空间GNN中，以学习分类的图表。大型休息状态以及性别分类任务的fMRI数据集的实验表明，DBGSL可以实现最新的性能。此外，对学习动态图的分析突出了与现有神经科学文献的发现相符的预测相关大脑区域。
translated by 谷歌翻译
部署AI驱动的系统需要支持有效人类互动的值得信赖的模型，超出了原始预测准确性。概念瓶颈模型通过在类似人类的概念的中间级别调节分类任务来促进可信度。这使得人类干预措施可以纠正错误预测的概念以改善模型的性能。但是，现有的概念瓶颈模型无法在高任务准确性，基于概念的强大解释和对概念的有效干预措施之间找到最佳的妥协，尤其是在稀缺完整和准确的概念主管的现实情况下。为了解决这个问题，我们提出了概念嵌入模型，这是一种新型的概念瓶颈模型，它通过学习可解释的高维概念表示形式而超出了当前的准确性-VS解关性权衡。我们的实验表明，嵌入模型（1）达到更好或竞争性的任务准确性W.R.T. W.R.T.没有概念的标准神经模型，（2）提供概念表示，以捕获有意义的语义，包括其地面真相标签，（3）支持测试时间概念干预措施，其在测试准确性中的影响超过了标准概念瓶颈模型，以及（4）规模对于稀缺的完整概念监督的现实条件。
translated by 谷歌翻译
图形神经网络的不透明推理导致缺乏人类的信任。现有的图形网络解释器试图通过提供事后解释来解决此问题，但是，它们无法使模型本身更容易解释。为了填补这一空白，我们介绍了概念编码器模块，这是图形网络的第一个可区分概念 - 发现方法。所提出的方法使图形网络可以通过首先发现图形概念，然后使用这些来解决任务来解释。我们的结果表明，这种方法允许图形网络：（i）达到模型准确性与它们的等效香草版本相当，（ii）发现有意义的概念，以实现高概念完整性和纯度得分，（iii）提供基于高质量的概念逻辑。对其预测的解释，以及（iv）在测试时支持有效的干预措施：这些可以提高人类的信任并显着提高模型绩效。
translated by 谷歌翻译
在不完整的数据集中对样本进行分类是机器学习从业人员的普遍目的，但并非平凡。在大多数现实世界数据集中发现缺失的数据，这些缺失值通常是使用已建立的方法估算的，然后进行分类现在完成，估算的样本。然后，机器学习研究人员的重点是优化下游分类性能。在这项研究中，我们强调必须考虑插补的质量。我们展示了如何评估质量的常用措施有缺陷，并提出了一类新的差异评分，这些分数着重于该方法重新创建数据的整体分布的程度。总而言之，我们强调了使用不良数据训练的分类器模型的可解释性损害。
translated by 谷歌翻译
最近关于其他方式的核化图像T1辅助MRI重建的研究表明，进一步加速MRI收购其他方式的潜力。大多数最先进的方法通过开发用于固定的欠采样模式的网络架构来实现改进，而不完全利用方式之间的互补信息。尽管可以简单地修改现有的下采样模式学习算法以允许完全采样的T1加权MR图像来辅助模式学习，但是可以实现重建任务的显着改进。为此，我们提出了一个迭代框架，优化了MRI获取的另一种方式的采样下采样模式，可以在不同的下抽样因子中补充完全采样的T1加权MR图像，同时共同优化T1辅助MRI重建模型。具体地，我们所提出的方法利用两种模式之间的潜在信息的差异来确定可以最大化T1加权MR图像的辅助功率在改善MRI重建时最大化的采样模式。与常用的下采样模式和最先进的方法相比，我们在公共数据集中展示了我们在公共数据集上的学习的下采样模式的卓越表现，可以联合优化重建网络和欠采样模式以8倍的取样因子。
translated by 谷歌翻译
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.
translated by 谷歌翻译
Artificial neural networks can learn complex, salient data features to achieve a given task. On the opposite end of the spectrum, mathematically grounded methods such as topological data analysis allow users to design analysis pipelines fully aware of data constraints and symmetries. We introduce a class of persistence-based neural network layers. Persistence-based layers allow the users to easily inject knowledge about symmetries (equivariance) respected by the data, are equipped with learnable weights, and can be composed with state-of-the-art neural architectures.
translated by 谷歌翻译
Quantifying motion in 3D is important for studying the behavior of humans and other animals, but manual pose annotations are expensive and time-consuming to obtain. Self-supervised keypoint discovery is a promising strategy for estimating 3D poses without annotations. However, current keypoint discovery approaches commonly process single 2D views and do not operate in the 3D space. We propose a new method to perform self-supervised keypoint discovery in 3D from multi-view videos of behaving agents, without any keypoint or bounding box supervision in 2D or 3D. Our method uses an encoder-decoder architecture with a 3D volumetric heatmap, trained to reconstruct spatiotemporal differences across multiple views, in addition to joint length constraints on a learned 3D skeleton of the subject. In this way, we discover keypoints without requiring manual supervision in videos of humans and rats, demonstrating the potential of 3D keypoint discovery for studying behavior.
translated by 谷歌翻译