More than 40 models have been established to date to determine the axial compressive behavior of noncircular (square or rectangular) concrete sections confined with fiber-reinforced polymers (FRPs) under concentric loadings. In this study, these models were classified into four groups, represented by nine analytical models. The accuracies of these models to capture the cyclic response of seven noncircular RC columns subjected to axial and reversible horizontal loads were evaluated. Specifically, the predicted responses revealed that the studied models predicted a premature FRP rupture failure mode, and in turn the simulation process was aborted early, revealing a low deformability capacity. By scrutinizing the available results, it was concluded that the axial compression behavior of the FRP-wrapped concrete was dependent on the applied loads, e.g., concentric axial load or axial load and bending moment. Subsequently, one of the examined models was adopted and revised to consider this effect. The modified model can accurately and safely simulate the lateral response of RC noncircular columns retrofitted with FRP, and it can be expanded for general application after verification against a notably large number of noncircular columns.

Clock synchronization has been a challenging task in the design of wireless networks because the synchronization accuracy suffers from uncertain transmission delay and/or packet loss due to poor wireless channel conditions. To address this problem, this paper develops a robust clock synchronization schemes based on matrix completion theory to improve the accuracy in presence of random transmission delay and packet loss. We propose a matrix completion based maximum likelihood estimator (MC-MLE) to estimate the clock offset and clock skew under Gaussian transmission delay model. Thanks to the denoise feature of matrix completion, the proposed schemes outperform the maximum likelihood estimator (MLE) in the presence of packet loss and random transmission delay. That is, the proposed schemes are closer to the Cramer-Rao lower bound (CRLB) than the MLE when the timestamp packets are randomly corrupted. The robustness and accuracy of the proposed schemes are validated by numerical results.

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Urban Heat Island (UHI) effect causes the increasing energy consumption for building and environment cooling. Reflective coating is an effective cool pavement technology to counterbalance UHI. However, the investigation of the optical properties and their relation of colored reflective pavement coatings at full solar spectrum are still in its infancy. This paper prepared ten non-white coating samples to evaluate the optical properties and thermal performance of pigments and coatings. It was founded that color lightness is a dominant factor of visible reflectance however it does not affect the near-infrared reflectance. The coatings doped in chrome achieved reflectance around 60% and the near-infrared reflectance was as high as the white coating around 95%. The relation between lightness and visible reflectance was linear for coatings in dark and medium color while the exponential growth was shown for the coating