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arXiv 2007.01263cs.LGstat.ML
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基于神经网络空间分析的离群点检测

Outlier Detection through Null Space Analysis of Neural Networks

University of Florida(佛罗里达大学)

Matthew Cook, Alina Zare, Paul Gader

摘要:

许多机器学习分类系统缺乏能力意识。具体地,许多系统缺乏识别何时异常值(例如,与训练数据分布不同且未在其中表示的样本)被呈现给系统。检测异常值的能力具有实际意义,因为它可以帮助系统在遇到意外数据时以合理的方式运行。在先前的工作中,离群值检测通常在与分类模型不同的处理管道中进行。因此,对于一个包含离群值检测和分类的完整系统,必须训练两个模型,从而增加了该方法的整体复杂性。在本文中,我们使用的零空间的概念,集成离群值检测方法直接到一个神经网络用于分类。我们的方法,称为神经网络的空间分析(NuSA),其工作原理是计算和控制的零空间投影的大小,数据通过网络。使用这些预测,我们可以计算出一个可以区分正常和异常数据的分数。结果表明,用NuSA训练的网络保留了它们的分类性能,同时也能够以类似于常用离群值检测算法的速度检测离群值。

英文摘要:

Many machine learning classification systems lack competency awareness. Specifically, many systems lack the ability to identify when outliers (e.g., samples that are distinct from and not represented in the training data distribution) are being presented to the system. The ability to detect outliers is of practical significance since it can help the system behave in an reasonable way when encountering unexpected data. In prior work, outlier detection is commonly carried out in a processing pipeline that is distinct from the classification model. Thus, for a complete system that incorporates outlier detection and classification, two models must be trained, increasing the overall complexity of the approach. In this paper we use the concept of the null space to integrate an outlier detection method directly into a neural network used for classification. Our method, called Null Space Analysis (NuSA) of neural networks, works by computing and controlling the magnitude of the null space projection as data is passed through a network. Using these projections, we can then calculate a score that can differentiate between normal and abnormal data. Results are shown that indicate networks trained with NuSA retain their classification performance while also being able to detect outliers at rates similar to commonly used outlier detection algorithms.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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