Feature selection from high-order tensorial data via sparse decomposition

Principal component analysis (PCA) suffers from the fact that each principal component (PC) is a linear combination of all the original variables, thus it is difficult to interpret the results. For this reason, sparse PCA (sPCA), which produces modified PCs with sparse loadings, arises to clear away this interpretation puzzlement. However, as a result of that sPCA is limited in handling vector-represented data, if we use sPCA to reduce the dimensionality and select significant features on the real-world data which are often naturally represented by high-order tensors, we have to reshape them into vectors beforehand, and this will destroy the intrinsic data structures and induce the curse of dimensionality. Focusing on this issue, in this paper, we address the problem to find a set of critical features with multi-directional sparse loadings directly from the tensorial data, and propose a novel method called sparse high-order PCA (sHOPCA) to derive a set of sparse loadings in multiple directions. The computational complexity analysis is also presented to illustrate the efficiency of sHOPCA. To evaluate the proposed sHOPCA, we perform several experiments on both synthetic and real-world datasets, and the experimental results demonstrate the merit of sHOPCA on sparse representation of high-order tensorial data. (c) 2012 Elsevier B.V. All rights reserved.