Sensitivity analysis on dynamic responses of geometrically imperfect base excited cantilevered beams

The non-linear non-planar dynamic responses of a near-square cantilevered geometrically imperfect (i.e., slightly curved) beam under harmonic primary resonant base excitation with a one-to-one internal resonance is investigated. By assuming two different geometric imperfection shapes, the sensitivity of the perfect beam model predicted limit-cycles to small geometric imperfections is analyzed by continuing them versus the imperfection parameter incorporating the imperfect beam model. This was carried out by assuming that the corresponding frequency detuning parameter associated with each limit-cycle is fixed. Also, other possible branches of dynamic solutions for the corresponding fixed detuning parameter within the interval of the imperfection amplitude are determined and the importance of accounting for the small geometric imperfections is discussed

A model-free ratio based nonlocal framework for denoising of SAR and TomoSAR data

This paper introduces a general patch-based model-free framework for despeckling of single and multi-baseline synthetic aperture radar (SAR) image. Particularly, the method is based on the empirical distribution similarity between the patch containing the pixel to be restored and the patch containing a candidate similar pixel. In order to decide whether the patches follow a similar distribution, the Kolmogorov-Smirnov test is adapted. Finally, within the restoration process, the selected similar pixels are aggregated based on their relative importance obtained according to their distribution similarities. Experimental validation of the proposed methodology is provided using different real data sets and compared with existing NLSAR approach in relation to single SAR image despeckling and tomographic application for the 3D reflectivity reconstruction of volumetric media as well as permanent scatterer detection in urban environments