Showing papers by "Palaniappan Ramu published in 2015"
TL;DR: An attempt has been made to use curvelet transforms which permit identifying the coefficients that store the crucial information about diagnosis in ECG steganography to validate that coefficients around zero are ideal for watermarking to minimize deterioration and there is no loss in the data retrieved.
56 citations
05 Nov 2015
TL;DR: This study evaluates the performance of ECG steganography to ensure secured transmission of patient data where an abnormal ECG signal is used as cover signal and metrics such as Peak Signal to Noise Ratio, Percentage Residual Difference, Kullback-Leibler distance and Bit Error Rate are used.
Abstract: Security and privacy of patient data is a vital requirement during exchange/storage of medical information over communication network. Steganography method hides patient data into a cover signal to prevent unauthenticated accesses during data transfer. This study evaluates the performance of ECG steganography to ensure secured transmission of patient data where an abnormal ECG signal is used as cover signal. The novelty of this work is to hide patient data into two dimensional matrix of an abnormal ECG signal using Discrete Wavelet Transform and Singular Value Decomposition based steganography method. A 2D ECG is constructed according to Tompkins QRS detection algorithm. The missed R peaks are computed using RR interval during 2D conversion. The abnormal ECG signals are obtained from the MIT-BIH arrhythmia database. Metrics such as Peak Signal to Noise Ratio, Percentage Residual Difference, Kullback-Leibler distance and Bit Error Rate are used to evaluate the performance of the proposed approach.
9 citations
TL;DR: In this article, the authors proposed Alpha shapes, a computational geometry technique to approximate the boundaries of the failure domain to estimate reliability and perform optimization of a tube impacting a rigid wall and a tuned mass damper.
Abstract: Treatment of uncertainties in structural design involves identifying the boundaries of the failure domain to estimate reliability. When the structural responses are discontinuous or highly nonlinear, the failure regions tend to be an island in the design space. The boundaries of these islands are to be approximated to estimate reliability and perform optimization. This work proposes Alpha (?) shapes, a computational geometry technique to approximate such boundaries. The ? shapes are simple to construct and only require Delaunay Tessellation. Once the boundaries are approximated based on responses sampled in a design space, a computationally efficient ray shooting algorithm is used to estimate the reliability without any additional simulations. The proposed approach is successfully used to decompose the design space and perform Reliability based Design Optimization of a tube impacting a rigid wall and a tuned mass damper.
9 citations
TL;DR: A participatory framework to identify criteria and their weights are used as parameters to develop a quantitative model for evaluating efficiency of each resource management system and can be used to plan other resource management systems in various regions.
Abstract: While planning resource management systems in rural areas, it is important to consider criteria that are specific to the local social conditions. Such criteria might change from one region to another and are hence best identified using a participatory approach. In this work, we propose a participatory framework to identify such criteria and derive their weights. These identified criteria and their weights are used as parameters to develop a quantitative model for evaluating efficiency of each system. Such a model can serve as a support tool for stakeholders to simulate and analyze “what-if” scenarios, evaluate alternatives, and select one which best satisfies their requirements. We use existing systems to test the model by comparing efficiencies evaluated by the model to efficiencies perceived by the stakeholders. The model is calibrated by repeating the process until statistically significant correlation is achieved between evaluated and perceived efficiencies. The novelty of the proposed framework lies in treating efficiencies perceived by the stakeholders as the ground truth since they know these systems well and are their ultimate users. The framework is successfully demonstrated using case study of rainwater harvesting (RWH) systems in an Indian village. The resulting calibrated model can be used to plan new RWH systems in this region and similar regions elsewhere. The framework can be used to plan other resource management systems in various regions.
8 citations
01 Jan 2015
TL;DR: The primary aim of this work is to provide a simple methodology for the robust optimal design of the Savonius wind turbine using the traditional Taguchi method and dynamic computational fluid dynamics models of the design sets.
Abstract: The Savonius wind turbine, a class of vertical axis wind turbine (VAWT), is simple and provides a better cost-benefit ratio. It works on the principle of differential drag and is effective in rooftop and ground mounting. Despite the advantages of Savonius wind rotors, they are not preferred due to their low aerodynamic performance levels. In order to address this, several experimental and numerical studies have been carried out in recent years. The primary aim of this work is to provide a simple methodology for the robust optimal design of the Savonius wind turbine. In the parameter design stage, the performance of the turbine is maximized using the traditional Taguchi method. An L27 orthogonal array is used considering five factors of three levels each, which affect C p . Wind speed is considered to be the noise factor. Signal-noise ratio (SNR) metric is used to find the optimal settings for robust design. The aerodynamic performance of the turbine is investigated through dynamic computational fluid dynamics (CFD) models of the design sets. The numerical models used for the simulations are also discussed.
4 citations