Publication6

In this extended abstract, we propose a pipelined parallel architecture for face detection that is appropriate for implementation on a multicore environment. The architecture comprises of modules for video frame acquisition, skin pixel detection, binarization, morphological operations and connected component analysis operating in sequence on an image frame. Successive lines of a frame are processed in a pipeline on multicores. Embedded system realization on a multicore XMOS microcontroller runs the drivers for interfacing image sensor and LCD on different cores along with the various stages of the image processing pipeline. The realization achieves a frame rate of 8 frames/second for an image size of 480×272. Further, the solution is area-efficient and is based on a single XMOS sliceKIT with support for camera, LCD and other units.

This article develops a method to generate ground motion time histories that maximize the response of a given linearly elastic structure. The root mean square (RMS) level of the input power spectral density (PSD) is used as a strong motion parameter. It is related to seismological data that is readily available. An empirical relation to estimate RMS value of the PSD from peak ground acceleration, magnitude, rupture distance, and shear wave velocity is derived from world-wide strong motion data. The ground motion is obtained by solving the inverse problem such that the structural response is maximized under the constraint of fixed value of RMS level of the input PSD enforced using a Lagrange multiplier. The proposed methodology is illustrated for a single-degree of freedom system, a six storey building and an earthen dam. It is shown that the critical PSD obtained in all the cases is a narrow band process resulting in stochastic resonance and not a Dirac-delta function with the entire energy of the system concentrated at its natural frequency. Moreover, the critical excitation samples generated using this critical PSD resembles actual earthquake acceleration time histories.

ECG steganography allows secured transmission of patient data that are tagged to the ECG signals. Signal deterioration leading to loss of diagnosis information and inability to retrieve patient data fully are the major challenges with ECG steganography. In this work, an attempt has been made to use curvelet transforms which permit identifying the coefficients that store the crucial information about diagnosis. The novelty of the proposed approach is the usage of curvelet transform for ECG steganography, adaptive selection of watermark location and a new threshold selection algorithm. It is observed that when coefficients around zero are modified to embed the watermark, the signal deterioration is the least. In order to avoid overlap of watermark, an n × n sequence is used to embed the watermark. The imperceptibility of the watermark is measured using metrics such as Peak Signal to Noise Ratio, Percentage Residual Difference and Kullback-Leibler distance. The ability to extract the patient data is measured by the Bit Error Rate. Performance of the proposed approach is demonstrated on the MIT-BIH database and the results validate that coefficients around zero are ideal for watermarking to minimize deterioration and there is no loss in the data retrieved. For an increased patient data size, the cover signal deteriorates but the Bit Error Rate is zero. Therefore the proposed approach does not affect diagnosability and allows reliable steganography.

We have developed a mild, intramolecular intercepted Meyer-Schuster (M-S) rearrangement for the synthesis of 2-acylfurans from corresponding cis-6-hydroxyhex-2-en-4-ynals. This reaction was found to be very general, and the starting materials are easily accessible. By this methodology the first synthesis of deoxy-nor-abiesesquine B, a sesquiterpene, was also achieved in three steps. The concept of adding two nucleophiles during the M-S rearrangement was introduced.

In this paper, the magnetoelectric coupling and ferroelectric ordering of the orthorhombic Dy1-xHoxMnO3 (x=0 and 0.1) are studied from the magnetodielectric response of the polycrystalline samples. The dielectric study on the DyMnO3 reveals ferroelectric transition at 18K along with an addition transition at 12K. We suggest that the transition at 12K could have originated from the polarization flop rather than being the rare earth magnetic ordering. The magnetodielectric study reveals a magnetoelectric coupling strength of 10%, which is stronger by two orders of magnitude in comparison to the hexagonal manganites. Surprisingly, the Ho3+ substitution in DyMnO3 suppresses the magnetoelectric coupling strength via the suppression of the spiral magnetic ordering. In addition, it also reduces the antiferromagnetic ordering and ferroelectric ordering temperatures. Overall, the studies show that the rare earth plays an important role in the magnetoelectric coupling strength through the modulation of spiral magnetic structure.