4 papers
Hybrid principal component analysis in multivariate allometric regression
Koji Tsukuda, Shun Matsuura
In biological data from allometry studies, the largest eigenvalue is typically dominant, and the gaps between minor eigenvalues are often narrow. Such proximity among small minor e…
On spectral clustering under non-isotropic Gaussian mixture models
Kohei Kawamoto, Yuichi Goto, Koji Tsukuda
We evaluate the misclustering probability of a spectral clustering algorithm under a Gaussian mixture model with a general covariance structure. The algorithm partitions the data i…
Robust -Estimation of Scatter Matrices via Precision Structure Shrinkage
Soma Nikai, Yuichi Goto, Koji Tsukuda
Maronna's and Tyler's -estimators are among the most widely used robust estimators for scatter matrices. However, when the dimension of observations is relatively high, their pe…
Equality between two general ridge estimators and equivalence of their residual sums of squares
Hirai Mukasa, Koji Tsukuda
General ridge estimators are typical linear estimators in a general linear model. The class of them includes some shrinkage estimators in addition to classical linear unbiased esti…