Indian Institute of Technology Bhubaneswar

About: Indian Institute of Technology Bhubaneswar is a education organization based out in Bhubaneswar, India. It is known for research contribution in the topics: Large Hadron Collider & Higgs boson. The organization has 1185 authors who have published 3132 publications receiving 48832 citations.

Real-Time Quality-Aware PPG Waveform Delineation and Parameter Extraction for Effective Unsupervised and IoT Health Monitoring Systems

Abstract: In this paper, we present a real-time quality-aware pulse waveform delineation and parameter extraction method for accurate and reliable measurements of pulse parameters from photoplethysmogram (PPG) signals. It consists of three major stages: the PPG signal quality assessment (PPG-SQA) using autocorrelation function (ACF) and number of threshold-crossings (NTC) features, the zero-frequency resonator (ZFR) based pulse onset and peak determination, and the pulse parameter extraction. The method is implemented on the Arduino Due with a 32-bit Atmel SAM3X8E ARM Cortex-M3 CPU, 512-kB flash memory, 96-kB SRAM, and 84-MHz clock speed. The method is evaluated on the recorded PPG signals and three standard PPG databases. The PPG-SQA algorithm achieves an average sensitivity (Se)=98.62%, specificity (Sp)=97.37%, and overall accuracy (OA)=98.09%. The algorithm achieves an average Se=99.88%, positive predictivity (Pp)=99.89, Se=99.82%, and Pp=99.95%, respectively with the delineation errors (mean ± standard deviation) of 8.45 ± 9.39 $ms$ and 0.23 ± 1.33 $ms$ for finding onsets and peaks, respectively. The statistical analysis demonstrates that the parameter measurement errors are minimum for most of the pulse cycles. Results show that our quality-aware PPG analysis scheme can achieve a false alarm rate reduction (FARR) of 97.36% which outperforms the other existing SQA algorithms. It can lead to save transmission and processing energy from 8.33% to 95.63% and 8.33% to 59.77% for a duration from 5 to 60 s, respectively. The method has great potential for low-energy IoT and unsupervised health monitoring devices.

Capillary Displacement of Viscous Liquids in Geometries with Axial Variations

Abstract: Axial variations in geometry and presence of viscous displaced fluid are known to alter the diffusive-dynamics of capillary imbibition of a wetting liquid. We here show that the coupled effect of axially varying capillary geometry and finite viscosity of the displaced fluid can lead to significant variations in both short and long time dynamics of imbibition. Based on a theoretical model and lattice Boltzmann simulations, we analyze capillary displacement of a viscous liquid in straight and diverging capillaries. At short times, the imbibition length scales proportionally with time as opposed to the diffusive-dynamics of imbibition of a single wetting liquid. Whereas, at long times, geometry-dependent power-law behavior occurs which qualitatively resembles single liquid imbibition. The distance at which the crossover between these two regimes occurs depends strongly on the viscosities of the imbibing and the displaced liquid. Additionally, our simulations show that the early time imbibition dynamics are a...

Synthesis of linear aperiodic array using Cauchy mutated cat swarm optimization

Abstract: A novel Cauchy mutated cat swarm optimization (CMCSO) that features effective global search capabilities with fast convergence is introduced in this paper. The Cauchy mutation enables the cats of the cat swarm optimization (CSO) algorithm to seek their positions in directions that avoid the problem of premature convergence and local optima. In this communication, CMCSO is applied to the synthesis of linear aperiodic arrays for minimizing sidelobe level and controlling the null positions. Various synthesis examples are considered and the obtained results are compared with linear aperiodic array designs from literature. Numerical results demonstrate that the proposed method is superior to existing methods in terms of accuracy and convergence speed. Some of the synthesized aperiodic array designs are implemented with wire dipole antenna elements using a full-wave electromagnetic simulator. Furthermore, experiments are conducted on several standard benchmark complex multimodal problems to demonstrate the effectiveness of the proposed method. The sensitivity analysis is performed on different parameters of CMCSO to demonstrate their influence on the overall performance of the benchmark and antenna array synthesis problems.

Variability in the ENSO-induced southern hemispheric circulation and Antarctic sea ice extent

Abstract: The linkages between the El Nino Southern Oscillation (ENSO) and the sea ice extent (SIE) in the Weddell Sea (South Atlantic) and the Bellingshausen–Amundsen Sea (South-Eastern Pacific) sectors of the Southern Ocean have been studied for the period 1979–2005 using crosswavelet analysis. The analysis showed that the relationship between the tropical expression of ENSO and the SIE in these two areas are different before and after 1992. Further, we investigated the structure and strength of the regional Ferrel cell (RFC) during El Nino and La Nina episodes using composite latitude–pressure cross-sections of wind anomalies for these two periods. Contrasting features were observed in the structure and strength of the RFC before and after 1992 in both, the South Atlantic and the South-Eastern Pacific. These modulations in the RFC control the heat transport from the tropics to high latitudes and hence the extent of sea ice in both the regions. We propose that the modulation of the RFC is responsible for the phase shift in the tropical–polar teleconnection.