Natural frequency of beams with embedded piezoelectric sensors and actuators

A mathematical model is developed to study the natural frequency of beams with embedded piezoelectric sensors and actuators. The piezoelectric sensors/actuators in a non-piezoelectric matrix (host beam) are analyzed as two inhomogeneity problems by using Eshelby’s equivalent inclusion method. The natural frequency of the beam is determined from the variational principle in Rayleigh quotient form, which is expressed as functions of the elastic strain energy and dielectric energy of the piezoelectric sensors/actuators. The Euler-Bernoulli beam theory and Rayleigh-Ritz approximation technique are used in the present analysis. Parametric studies show that the size, volume fraction and location of the piezoelectric inclusions significantly influence the natural frequency of the beam

A Hybrid Intelligent Early Warning System for Predicting Economic Crises: The Case of China

This paper combines artificial neural networks (ANN), fuzzy optimization and time-series econometric models in one unified framework to form a hybrid intelligent early warning system (EWS) for predicting economic crises. Using quarterly data on 12 macroeconomic and financial variables for the Chinese economy during 1999 and 2008, the paper finds that the hybrid model possesses strong predictive power and the likelihood of economic crises in China during 2009 and 2010 remains high.Computational intelligence; artificial neural networks; fuzzy optimization; early warning system; economic crises

Understanding Kernel Size in Blind Deconvolution

Most blind deconvolution methods usually pre-define a large kernel size to guarantee the support domain. Blur kernel estimation error is likely to be introduced, yielding severe artifacts in deblurring results. In this paper, we first theoretically and experimentally analyze the mechanism to estimation error in oversized kernel, and show that it holds even on blurry images without noises. Then to suppress this adverse effect, we propose a low rank-based regularization on blur kernel to exploit the structural information in degraded kernels, by which larger-kernel effect can be effectively suppressed. And we propose an efficient optimization algorithm to solve it. Experimental results on benchmark datasets show that the proposed method is comparable with the state-of-the-arts by accordingly setting proper kernel size, and performs much better in handling larger-size kernels quantitatively and qualitatively. The deblurring results on real-world blurry images further validate the effectiveness of the proposed method.Comment: Accepted by WACV 201

Mechanism of phospholipid induction of cell migration

Lysophosphatidic acid (LPA) is a potent bioactive lipid component of oxidized low density lipoproteins (oxLDL). High concentrations of LPA have been detected in human atherosclerotic plaques. Our data has shown that LPA highly induces smooth muscle cell (SMC) migration. Cyr61, a matricellular protein, which also accumulates in human atherosclerotic plaques, has been implicated in the injury-induced neointimal formation. Smooth muscle cell migration is a key event in the development of atherosclerosis, and it contributes to the progressive growth of atherosclerotic lesions. Data generated by this study demonstrate that LPA markedly induces Cyr61 expression in mouse aortic smooth muscle cells (MASMC). We hypothesized that LPA-induced matricellular Cyr61 mediates LPA-induced MASMC migration. To date, little is known about the relationship between LPA and Cyr61 in smooth muscle cells; the signaling pathway leading to LPA-induced Cyr61 is unknown. Furthermore, whether Cyr61 contributes to LPA-induced cell migration is unrevealed. Our study demonstrates that LPA, by binding to LPA1 receptor, activates the intracellular signaling pathway leading to the activation of PKCdelta which in turn contributes to the increased expression of Cyr61 in MASMCs. Interestingly, we found that after LPA-induced Cyr61 mRNA has been translated into its protein intracellularly, the de novo synthesized proteins promptly accumulate in the Golgi apparatus and then translocalize to the extracellular matrix. Importantly, our data reveal a novel LPA/Cyr61 pathway in controlling MASMC migration. Understanding the mechanism underlying LPA induction of Cyr61 provides new insight into pathogenesis of atherosclerosis