4 research outputs found
C-SURE: Shrinkage Estimator and Prototype Classifier for Complex-Valued Deep Learning
The James-Stein (JS) shrinkage estimator is a biased estimator that captures
the mean of Gaussian random vectors.While it has a desirable statistical
property of dominance over the maximum likelihood estimator (MLE) in terms of
mean squared error (MSE), not much progress has been made on extending the
estimator onto manifold-valued data.
We propose C-SURE, a novel Stein's unbiased risk estimate (SURE) of the JS
estimator on the manifold of complex-valued data with a theoretically proven
optimum over MLE. Adapting the architecture of the complex-valued SurReal
classifier, we further incorporate C-SURE into a prototype convolutional neural
network (CNN) classifier. We compare C-SURE with SurReal and a real-valued
baseline on complex-valued MSTAR and RadioML datasets.
C-SURE is more accurate and robust than SurReal, and the shrinkage estimator
is always better than MLE for the same prototype classifier. Like SurReal,
C-SURE is much smaller, outperforming the real-valued baseline on MSTAR
(RadioML) with less than 1 percent (3 percent) of the baseline sizeComment: Submitted to CVPR PBVS worksho
HUNK inhibits epithelial-mesenchymal transition of CRC via direct phosphorylation of GEF-H1 and activating RhoA/LIMK-1/CFL-1
Abstract Epithelial-mesenchymal transition (EMT) is associated with the invasive and metastatic phenotypes in colorectal cancer (CRC). However, the mechanisms underlying EMT in CRC are not completely understood. In this study, we find that HUNK inhibits EMT and metastasis of CRC cells via its substrate GEF-H1 in a kinase-dependent manner. Mechanistically, HUNK directly phosphorylates GEF-H1 at serine 645 (S645) site, which activates RhoA and consequently leads to a cascade of phosphorylation of LIMK-1/CFL-1, thereby stabilizing F-actin and inhibiting EMT. Clinically, the levels of both HUNK expression and phosphorylation S645 of GEH-H1 are not only downregulated in CRC tissues with metastasis compared with that without metastasis, but also positively correlated among these tissues. Our findings highlight the importance of HUNK kinase direct phosphorylation of GEF-H1 in regulation of EMT and metastasis of CRC