论文标题

在加标协方差模型下的高维二次判别分析

High-Dimensional Quadratic Discriminant Analysis under Spiked Covariance Model

论文作者

Sifaou, Houssem, Kammoun, Abla, Alouini, Mohamed-Slim

论文摘要

二次判别分析(QDA)是一种广泛使用的分类技术,将线性判别分析(LDA)分类器推广到类别之间不同协方差矩阵的情况。为了使QDA分类器得出高分类性能,需要对协方差矩阵进行准确的估计。在高维度设置中,这样的任务变得更加具有挑战性,其中观察数与特征维度相当。在这种情况下,提高QDA分类器性能的一种流行方法是使协方差矩阵正规化,将名称正规QDA(R-QDA)定为相应的分类器。在这项工作中,我们考虑了种群协方差矩阵具有尖峰协方差结构的情况,该模型通常在几种应用中假定。在经典QDA的基础上,我们提出了一种新颖的二次分类技术,其选择的参数是最大化的,以使Fisher-Distiscistrimination的比例最大化。数值模拟表明,所提出的分类器不仅胜过合成和真实数据的经典R-QDA,而且还需要较低的计算复杂性,使其适合于高维设置。

Quadratic discriminant analysis (QDA) is a widely used classification technique that generalizes the linear discriminant analysis (LDA) classifier to the case of distinct covariance matrices among classes. For the QDA classifier to yield high classification performance, an accurate estimation of the covariance matrices is required. Such a task becomes all the more challenging in high dimensional settings, wherein the number of observations is comparable with the feature dimension. A popular way to enhance the performance of QDA classifier under these circumstances is to regularize the covariance matrix, giving the name regularized QDA (R-QDA) to the corresponding classifier. In this work, we consider the case in which the population covariance matrix has a spiked covariance structure, a model that is often assumed in several applications. Building on the classical QDA, we propose a novel quadratic classification technique, the parameters of which are chosen such that the fisher-discriminant ratio is maximized. Numerical simulations show that the proposed classifier not only outperforms the classical R-QDA for both synthetic and real data but also requires lower computational complexity, making it suitable to high dimensional settings.

扫码加入交流群

加入微信交流群

微信交流群二维码

扫码加入学术交流群,获取更多资源