Observational Constraints on Varying Alpha in Λ(α)\Lambda(\alpha)CDM Cosmology

In this work, we consider the so-called $\Lambda(\alpha)$CDM cosmology with $\Lambda\propto\alpha^{-6}$ while the fine-structure "constant" $\alpha$ is varying. In this scenario, the accelerated expansion of the universe is driven by the cosmological "constant" $\Lambda$ (equivalently the vacuum energy), and the varying $\alpha$ is driven by a subdominant scalar field $\phi$ coupling with the electromagnetic field. The observational constraints on the varying $\alpha$ and $\Lambda\propto\alpha^{-6}$ models with various couplings $B_F(\phi)$ between the subdominant scalar field $\phi$ and the electromagnetic field are considered.Comment: 13 pages, 5 figures, 1 table, revtex4; v2: appendix removed, Commun. Theor. Phys. in press; v3: published version. arXiv admin note: text overlap with arXiv:1605.0457

Learning distance to subspace for the nearest subspace methods in high-dimensional data classification

The nearest subspace methods (NSM) are a category of classification methods widely applied to classify high-dimensional data. In this paper, we propose to improve the classification performance of NSM through learning tailored distance metrics from samples to class subspaces. The learned distance metric is termed as ‘learned distance to subspace’ (LD2S). Using LD2S in the classification rule of NSM can make the samples closer to their correct class subspaces while farther away from their wrong class subspaces. In this way, the classification task becomes easier and the classification performance of NSM can be improved. The superior classification performance of using LD2S for NSM is demonstrated on three real-world high-dimensional spectral datasets