This study presents a new method to find the optimal control forces for active tuned mass damper. The method uses three algorithms: discrete wavelet transform (DWT), particle swarm optimization (PSO), and linear quadratic regulator (LQR). DWT is used to obtain the local energy distribution of the motivation over the frequency bands. PSO is used to determine the gain matrices through the online update of the weighting matrices used in the LQR controller while eliminating the trial and error. The method is tested on a 10‐story structure subject to several historical pulse‐like near‐fault ground motions. The results indicate that the proposed method is more effective at reducing the displacement response of the structure in real time than conventional LQR controllers.

The principal purpose of this article is to present a novel method based on particle swarm optimization (PSO) and wavelet packet transform (WPT) techniques and multilayer feed‐forward (MLFF) neural networks, in order to generate spectrum‐compatible near‐field artificial earthquake accelerograms. PSO is employed to optimize the weight values of the networks. Moreover, to improve the training efficiency principal component analysis (PCA) is used, as a reduction technique. The proposed PSO‐based MLFF (PSOBMLFF) neural network develops an inverse mapping from compacted and reduced spectrum coefficients into metamorphosed accelerogram wavelet packet coefficients. In this research, to produce compatible synthetic long‐period near‐field ground motions with median predicted spectra, the attenuation of peak ground velocity (PGV) with the close horizontal distance (R), moment magnitude (M), and time‐average shear‐wave velocity from the surface to 30 m (Vs30) has been developed using nonlinear regression analysis.

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Phase retrieval is a central problem in coherent x-ray diffraction microscopy. Various methods have been proposed to solve the problem with the most successful being iterative methods with a finite spatial support constraint. In this work, a new constraint is formulated in the wavelet domain using low-resolution a priori information. Experimental results indicate that the constraint is sufficient to reconstruct an object from Fourier modulus measurements.

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SUMMARYA structure that has a permanent offset from a true vertical line is commonly referred to as being 'out-ofplumb'. Out-of-plumb may result from construction tolerances or post-earthquake permanent deformations in steel buildings. This paper quantifies the displacements of buildings with out-of-plumb in subsequent seismic events by means of inelastic dynamic time history analysis. Structures considered have different structural heights, force design reduction factors (R), and target inter-story drifts. It is shown that buildings with greater out of plumb and force design reduction factor have larger normalized peak inter-story drift ratio and ratio of residual-to-peak drift. Also, the ratio of residual-to-peak drift was not strongly dependent on structural height or design drift. A design procedure and example provided, based on the results obtained, show how peak and residual inter-story drift ratio can be estimated.