LAI YING-CHENG
Email Address
cscly@nus.edu.sg
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Publication Uncovering evolutionary ages of nodes in complex networks(2012-03) Zhu, G.-M.; Yang, H.J.; Yang, R.; Ren, J.; Li, B.; Lai, Y.-C.; PHYSICSIn a complex network, different groups of nodes may have existed for different amounts of time. To detect the evolutionary history of a network is of great importance. We present a spectral-analysis based method to address this fundamental question in network science. In particular, we find that there are complex networks in the real-world for which there is a positive correlation between the eigenvalue magnitude and node age. In situations where the network topology is unknown but short time series measured from nodes are available, we suggest to uncover the network topology at the present (or any given time of interest) by using compressive sensing and then perform the spectral analysis. Knowledge of ages of various groups of nodes can provide significant insights into the evolutionary process underpinning the network. It should be noted, however, that at the present the applicability of our method is limited to the networks for which information about the node age has been encoded gradually in the eigen-properties through evolution. © 2012 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.Publication Enhancing mammalian hearing by a balancing between spontaneous otoacoustic emissions and spatial coupling(2012-04) Liu, Z.; Li, B.; Lai, Y.-C.; PHYSICSNonlinear dynamics has provided significant insights into the origin of frequency discrimination and signal amplification underlying mammalian hearing. Existing signal amplification models, however, tend to ignore two basic known aspects of the hearing: spontaneous otoacoustic emissions (SOAEs) and intrinsic dynamical coupling in the cochlea. We construct and study a class of coupled-oscillator models to remedy this deficiency. Our analysis and computations reveal that the interplay and balance between the two aspects can naturally explain the phenomena of frequency discrimination and signal amplification and, more strikingly, the origin of hearing loss, all at a quantitative level. In the presence of SOAEs, there exists a critical coupling threshold below which hearing loss can occur, suggesting enhancement of coupling as a potentially effective therapeutic strategy to restore or even significantly enhance hearing. © Europhysics Letters Association, 2012.