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Author

V. Jagadeesh Kumar

Other affiliations: Indian Institutes of Technology
Bio: V. Jagadeesh Kumar is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Signal conditioning & Capacitive sensing. The author has an hindex of 15, co-authored 83 publications receiving 637 citations. Previous affiliations of V. Jagadeesh Kumar include Indian Institutes of Technology.


Papers
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Proceedings ArticleDOI
15 May 2016
TL;DR: Using the proposed analytical model, a method of estimation of the concentration of hemoglobin in arterial blood is derived and the results of the clinical study establish the viability of measuring hemoglobin concentration, noninvasively, using magnetic plethysmogram.
Abstract: A method for determining the concentration of hemoglobin in arterial blood, non invasively, is explored in this paper. A permanent magnet is placed just above the radial artery of a person whose hemoglobin concentration is to be ascertained. The flux produced by the permanent magnet (that links with the blood flow in the radial artery) is sensed to obtain a signal called magnetic plethysmogram (MPG). In this paper, an analytical model for a magnetic plethysmogram is derived. Using the proposed analytical model, a method of estimation of the concentration of hemoglobin in arterial blood is derived. The proposed method is then validated through a limited clinical study. The results of the clinical study establish the viability of measuring hemoglobin concentration, noninvasively, using magnetic plethysmogram.

1 citations

Journal ArticleDOI
24 Aug 2020
TL;DR: In this article, a noncontact capacitively coupled probe for the measurement of the liquid fill level and conductivity in a partially filled but horizontally kept pipe is presented, which is designed to provide voltage directly proportional to the resistance of the water column.
Abstract: A noncontact capacitively coupled probe for the measurement of the liquid fill level and conductivity in a partially filled but horizontally kept pipe is presented. Capacitively coupled electrodes are used for conductivity measurements, but the error is high when the tube is partially filled with liquid. In this letter, we propose to use the values of the coupling capacitors formed between the liquid column and conductive electrodes to calculate the fill level and estimate the conductivity of water in the pipe. The resistance of the liquid column is determined using a recently reported autobalancing signal conditioning circuit. The circuit is designed to provide voltage directly proportional to the resistance of the water column. Voltages at the relevant nodes of the circuit are tapped to compute the equivalent coupling capacitance values. The resistance of the liquid column along with fill level determined through coupling capacitance values helps in measuring the conductivity of water flowing through the pipe. A worst-case error of ±0.9% was obtained in measuring the conductivity, and a worst-case error less than 0.52% was observed in the water fill level measurement from a prototype noncontact water conductivity measurement probe for a partially filled pipe that has been developed and tested.

1 citations

Proceedings ArticleDOI
05 May 2009
TL;DR: In this paper, the viscoelastic properties of polyacrylamide gel based tissue mimicking phantoms have been measured by subjecting the samples to cyclic loading.
Abstract: Most biological soft tissues exhibit viscous behavior in addition to their well known elastic properties. Polyacrylamide gel based tissue mimicking phantoms have been developed. The viscoelastic properties of these phantoms were measured by subjecting the samples to cyclic loading. Samples prepared with varying concentration of monomer were considered so as to cover the normal and pathological lesions. Results obtained in the measurement are fit to three models - Maxwell, Kelvin-Voigt (KV) and Kelvin-Voigt fractional derivative (KVFD) models, in order to determine the best fitting model. KVFD model is found to be best fitting model for the experimental data obtained.

1 citations

Book ChapterDOI
01 Jan 2021
TL;DR: In this article, the authors describe in detail a couple of novel methods of oxygen saturation calculation using the red and IR photoplethysmography (PPG) obtained using red and infrared wavelength light sources and an empirical equation.
Abstract: The method of photoplethysmography (PPG) detailed in Chapters 1 and 2 gained enormous prominence due to the development of pulse oximetry. In pulse oximetry, the fact that hemoglobin bound with oxygen (called oxyhemoglobin) and hemoglobin without oxygen (deoxy-hemoglobin or reduced hemoglobin) absorb/reflect light differently is exploited in ascertaining, noninvasively, oxygen saturation in arterial blood. Most pulse oximeters that are in existence today use a couple of PPGs obtained using red and infrared wavelength light sources and calculate oxygen saturation in arterial blood using the red and IR PPGs and an empirical equation. This chapter details the development of pulse oximetry. It describes in detail a couple of novel methods of oxygen saturation calculation using the red and IR PPGs. The methods presented here do not need any calibration to be performed.

1 citations


Cited by
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Journal ArticleDOI
TL;DR: A new ECG enhancement method based on the recently developed empirical mode decomposition (EMD) that is able to remove both high-frequency noise and BW with minimum signal distortion and is validated through experiments on the MIT-BIH databases.

604 citations

Journal ArticleDOI
TL;DR: A comprehensive review of wave energy converters and air turbines can be found in this paper, together with a survey of theoretical, numerical and experimental modelling techniques of OWC converters.

594 citations

Journal ArticleDOI
TL;DR: This study presents an overview of the wide range of IPPG systems currently being introduced along with examples of their application in various physiological assessments and believes that the widespread acceptance ofIPPG is happening, and it will dramatically accelerate the promotion of this healthcare model in the near future.
Abstract: Photoplethysmography (PPG) is a noninvasive optical technique for detecting microvascular blood volume changes in tissues. Its ease of use, low cost and convenience make it an attractive area of research in the biomedical and clinical communities. Nevertheless, its single spot monitoring and the need to apply a PPG sensor directly to the skin limit its practicality in situations such as perfusion mapping and healing assessments or when free movement is required. The introduction of fast digital cameras into clinical imaging monitoring and diagnosis systems, the desire to reduce the physical restrictions, and the possible new insights that might come from perfusion imaging and mapping inspired the evolution of the conventional PPG technology to imaging PPG (IPPG). IPPG is a noncontact method that can detect heart-generated pulse waves by means of peripheral blood perfusion measurements. Since its inception, IPPG has attracted significant public interest and provided opportunities to improve personal healthcare. This study presents an overview of the wide range of IPPG systems currently being introduced along with examples of their application in various physiological assessments. We believe that the widespread acceptance of IPPG is happening, and it will dramatically accelerate the promotion of this healthcare model in the near future.

434 citations