House of Quality

/pdf/citizen-science-a-study-of-people-expertise-and-sustainable-3po1jwi9qc.pdf

Citizen Science: A Study of People, Expertise and Sustainable Development

International Joint Conference on Neural Networks

Computational methods in optimization considering uncertainties – An overview

Review of uncertainty-based multidisciplinary design optimization methods for aerospace vehicles

http://www2.mae.ufl.edu/nkim/Papers/paper42.pdf

Multiple tail median approach for high reliability estimation

Connected health enables patient centric interventions resulting in better healthcare and hence better living. In order to accomplish this, bio-signals, medical and diagnosis information are shared and accessed by multiple actors and it is important to protect the privacy of patient data. Steganography is widely used to protect patient data by hiding it in the medical information. Current work investigates ECG steganography using Discrete Wavelet Transform (DWT) and Quick Response (QR) code. Steganography deteriorates the ECG signal and it is important to minimize this deterioration to preserve diagnosability. 1D ECG signal is converted to 2D ECG image and decomposed into sub-bands by subjecting it to DWT. The novelty of the proposed approach lies in converting the patient data into QR code and using it as watermark in ECG steganography. The QR code is embedded in the 2D image using additive quantization scheme. The performance of proposed method is measured using Peak Signal to Noise Ratio, Percentage Residual Difference and Kullback-Leibler distance. These metrics are used as a measure of imperceptibility while the data loss during retrieval is measured by Bit Retrieval Rate. The proposed method is demonstrated on normal ECG signals obtained from MIT-BIH database for different QR code versions. Metrics reveal that imperceptibility decreased for increasing patient data size and increasing scaling factors. Metrics were independent of the sub-band and the proposed method allows reliable patient data protection with full retrieval ability.

https://link.springer.com/content/pdf/10.1007%2Fs13246-018-0695-y.pdf

QR code based patient data protection in ECG steganography

Pull out strength calculator for pedicle screws using a surrogate ensemble approach

Probability performance measure and probability sufficiency factor are two inverse reliability measures that have gained importance as alternate measures of safety. Inverse measures have several advantages, including improving accuracy in response surface approximations, computational efficiency, and allowing easy estimates of resources needed for achieving the target safety levels. This paper establishes the relationship between the two inverse measures, and describes their advantages compared to the direct measures of probability and reliability index. Methods to compute the inverse measures are also described. Reliability based design optimization with inverse measure is demonstrated with a beam design example.

/pdf/safety-factor-and-inverse-reliability-measures-2yam6p2yek.pdf

Safety Factor and Inverse Reliability Measures

Current study presents fluid flow analysis using CFD and a surrogate based framework for design optimization of Savonius wind turbines. The CFD model used for the study is validated with results from a physical model in water tunnel experiment. Four variables that best define blade geometry are considered and a feasible design space consisting of different combinations of these variables that provide positive overlap ratio is identified. The feasible space is then sampled with Latin hyper cube design of experiment. Numerical simulations utilizing K-epsilon turbulence model are performed at each point in the Design of Experiments to obtain coefficient of performance and weighted average surrogate (WAS) is fitted to them. Novelty of the current work is the use of WAS for design of savonius turbine. The WAS is an ensemble of surrogates that consists of polynomial response surface, kriging and radial basis functions. Error metrics reveal that WAS performs better compared to any surrogate individually thus avoiding misleading optima and eliminates surrogate dependent optima. WAS is used to explore the design space and perform optimization with limited number of CFD analyses. It is observed that at the optimal profile, there is more power on the rotors and primary recirculation in the immediate downstream of rotor is high, enforcing maximum momentum on turbine.

Palaniappan Ramu

Papers

Multiple tail median approach for high reliability estimation

QR code based patient data protection in ECG steganography

Pull out strength calculator for pedicle screws using a surrogate ensemble approach

Safety Factor and Inverse Reliability Measures

Optimal design of savonius wind turbines using ensemble of surrogates and CFD analysis