Shubhajit Chowdhury | IIIT Hyderabad (original) (raw)

Papers by Shubhajit Chowdhury

Research paper thumbnail of Simulation Studies for Non Invasive Classification of Ischemic and Hemorrhagic Stroke using Near Infrared Spectroscopy

Proceedings of the 12th International Joint Conference on Biomedical Engineering Systems and Technologies, 2019

This paper presents an approach to identify and classify the type of stroke, viz ischemic and hem... more This paper presents an approach to identify and classify the type of stroke, viz ischemic and hemorrhagic conditions. Ischemic stroke is caused by the blood clot and plaque present in the blood vessel. Hemorrhagic stroke, on the other hand, occurs when a rupture happens in the cerebrovascular artery or mid-cerebral artery causing impairments in blood flow and hence the supply of oxygen to the cerebral tissues. The current research analyses the blood flow velocity, the pressure profile of blood clot and plaque, and the condition at which ischemic and hemorrhagic stroke occurs. Simulation studies show the pressure on the blood vessel walls under ischemic and hemorrhagic stroke conditions and also that under nominal blood flow velocity the hemorrhage does not occur, but when the velocity is sufficient enough to increase the pressure on the wall, rupture of the mid-cerebral artery takes place. The simulation assumes the blood flow to be laminar, non-Newtonian, viscous, incompressible, and the arterial wall as elastic. Using the simulation model, an approach to classifying ischemic and hemorrhagic stroke using near infrared spectroscopy has been proposed in the paper.

Research paper thumbnail of Design of NIRS Probe Based on Computational Model to Find Out the Optimal Location for Non-Invasive Brain Stimulation

Journal of medical systems, Jan 29, 2018

The paper presents a computational model to analyse the electric field distribution on the cerebr... more The paper presents a computational model to analyse the electric field distribution on the cerebral cortex during high definition transcranial direct current stimulation (HD-tDCS) technique. The current research aims to improve the focality in term of magnitude of electric field (norm [E]) and magnitude of current density (norm [J]) in the gyri and sulci of white matter. The proposed computational model is used to predict the magnitude of current density and magnitude of electric field distribution generated across the target region of cerebral cortex for specific small size 1 × 1 cm multi-electrode HD-tDCS configurations. The current works aims at optimizing the number of electrodes and current density for multielectrode HD-tDCS configuration and weak current intensity is obtained by calculating surface area and penetration depth of target region of cerebral cortex. In terms of surface area and penetration depth 4 × 1 HD-tDCS and 2 mA weak dc current configuration has been selected...

Research paper thumbnail of Near-Infrared Spectroscopy – Electroencephalography-Based Brain-State-Dependent Electrotherapy: A Computational Approach Based on Excitation–Inhibition Balance Hypothesis

Frontiers in Neurology, 2016

FiGUre 1 | electroencephalography (eeG)-functional near-infrared spectroscopy (fnirs) joint-imagi... more FiGUre 1 | electroencephalography (eeG)-functional near-infrared spectroscopy (fnirs) joint-imaging during non-invasive brain stimulation (niBs) and neuromuscular electrical stimulation (nMes). Left panel: experimental setup for the upper limb, Right panel: EEG-fNIRS sensor montage along with NIBS stimulation electrodes [from Ref. (20)]. Figure adapted from Dutta et al. (19).

Research paper thumbnail of FPGA based signal processing: Prospects and Challenges

Research paper thumbnail of Modeling onset effects of transcranial direct current stimulation from NIRS-EEG joint-imaging : an ischemic stroke study

Effects of transcranial direct current stimulation (tDCS) from simultaneous recording of electroe... more Effects of transcranial direct current stimulation (tDCS) from simultaneous recording of electroencephalogram (EEG) and near infra red spectroscopy (NIRS) are presented. Here, tDCS has been shown to modulate cortical neural activity leading to changes in the EEG power spectrum. During neural activity, the electric currents from excitable membranes of brain tissue superimpose at a given location in the extracellular medium and generate a potential, which is referred to as the electroencephalogram (EEG) when recorded from the scalp. This neural activity is closely related, spatially and temporally, to cerebral blood flow (CBF) that supplies glucose via neurovascular coupling. The hemodynamic response to neural activity can be captured by near-infrared spectroscopy (NIRS), which enables continuous monitoring of cerebral oxygenation and blood volume. CBF is increased in brain regions with neural enhanced activity via metabolic coupling mechanisms. SUMMARY Simultaneous recording of NIRS ...

Research paper thumbnail of Performance enhancement in the associative processing of floating point numbers using multi-core superscalar architecture

TENCON 2008 - 2008 IEEE Region 10 Conference, 2008

Page 1. Performance Enhancement in the Associative Processing of Floating Point Numbers using Mul... more Page 1. Performance Enhancement in the Associative Processing of Floating Point Numbers using Multi-core Superscalar Architecture. Subhagya Pani Dept. of Electronics and Communication Engineering, Tezpur University, Tezpur, India Email: subha_pani@rediffmail.com ...

Research paper thumbnail of Fault tolerant design for low power hierarchical search motion estimation algorithms

2011 IEEE/IFIP 19th International Conference on VLSI and System-on-Chip, 2011

Research paper thumbnail of Design, Simulation and Testing of an Optimized Fuzzy Neural Network for Early Criticality Diagnosis

2008 First International Conference on Emerging Trends in Engineering and Technology, 2008

Page 1. Design, Simulation and Testing of an Optimized Fuzzy Neural Network for Early Criticality... more Page 1. Design, Simulation and Testing of an Optimized Fuzzy Neural Network for Early Criticality Diagnosis Shubhajit Roy Chowdhury1, Arijit Biswas2, Rini Chowdhury3 IC Design and Fabrication Centre, Department of Electronics ...

Research paper thumbnail of Non invasive estimation of blood glucose using near infra red spectroscopy and double regression analysis

2013 Seventh International Conference on Sensing Technology (ICST), 2013

A_DSiraci-inis paper presenis a unique lecnnique ior noninvasive estimation ol blood glucose conc... more A_DSiraci-inis paper presenis a unique lecnnique ior noninvasive estimation ol blood glucose concentration using near inlra red spectroscopy. 1 he spectroscopy has been perlormed at the second overtone ol glucose which lalls in the near inlra red region. Ihe near inlra red spectroscopy has been perlormed using transmission pnotopletnsymograpny (li(j). Ine analog Iront end system has been implemented to get tne riG signal at tne near inlra red wavelengths ol 1070nm, 95Unm, 935nm. Ihe II(J signal that has been obtained is processed and double regression analysis is carried out with the artilicial neural network lor estimating the glucose levels. 1 he root mean square error ol the prediction was 5.o4mg/d-L.

Research paper thumbnail of Smart Learning Environments for Teaching Electronics to Students

2013 IEEE Fifth International Conference on Technology for Education (t4e 2013), 2013

The paper presents an alternate approach of teaching electronics by hands on activities instead o... more The paper presents an alternate approach of teaching electronics by hands on activities instead of the conventional approach of classroom lectures and structured lab sessions. The current work applies the notion of Butterfly Model in developing three Learning by Doing (LbD) courses in Electronics viz. Digital System Design Using Verilog, VLSI Architectures, Topics in Embedded Systems. The effectiveness of these courses has been tested in the classroom on a population of 250 students with around 195 people giving positive feedback.

Research paper thumbnail of Maximum power point tracking of partially shaded solar photovoltaic arrays

Solar Energy Materials and Solar Cells, 2010

The paper presents the simulation and hardware implementation of maximum power point (MPP) tracki... more The paper presents the simulation and hardware implementation of maximum power point (MPP) tracking of a partially shaded solar photovoltaic (PV) array using a variant of Particle Swarm Optimization known as Adaptive Perceptive Particle Swarm Optimization (APPSO). Under partially shaded conditions, the photovoltaic (PV) array characteristics get more complex with multiple maxima in the power–voltage characteristic. The paper presents an

Research paper thumbnail of Field Programmable Gate Array Based Fuzzy Neural Signal Processing System for Differential Diagnosis of QRS Complex Tachycardia and Tachyarrhythmia in Noisy ECG Signals

Journal of Medical Systems, 2012

The paper reports of a Field Programmable Gate Array (FPGA) based embedded system for detection o... more The paper reports of a Field Programmable Gate Array (FPGA) based embedded system for detection of QRS complex in a noisy electrocardiogram (ECG) signal and thereafter differential diagnosis of tachycardia and tachyarrhythmia. The QRS complex has been detected after application of entropy measure of fuzziness to build a detection function of ECG signal, which has been previously filtered to remove power line interference and base line wander. Using the detected QRS complexes, differential diagnosis of tachycardia and tachyarrhythmia has been performed. The entire algorithm has been realized in hardware on an FPGA. Using the standard CSE ECG database, the algorithm performed highly effectively. The performance of the algorithm in respect of QRS detection with sensitivity (Se) of 99.74% and accuracy of 99.5% is achieved when tested using single channel ECG with entropy criteria. The performance of the QRS detection system has been compared and found to be better than most of the QRS detection systems available in literature. Using the system, 200 patients have been diagnosed with an accuracy of 98.5%.

Research paper thumbnail of Studies on Rat Brain Phantoms for the Development of Near-Infrared Spectroscopy (NIRS) System

Proceedings of the 11th International Joint Conference on Biomedical Engineering Systems and Technologies, 2018

The present work aims at developing static phantom for rat brain to model the inhomogeneities in ... more The present work aims at developing static phantom for rat brain to model the inhomogeneities in the brain tissues. The inhomogeneities have been modelled by varying the concentration of the fluids that mimic those inhomogeneities. The local variations in various parts of brain can be considered as different concentration of substances and accordingly having different optical attributes. Near-infrared spectroscopy (NIRS) has been used to detect and estimate these local changes that indicate different brain activities. The paper presents the development of static rat brain tissue phantoms and its analysis using a single channel near-infrared spectroscopy (NIRS) system. Homogeneous phantoms have been prepared with different concentrations of agarose and intralipid. For different concentrations, the NIRS signal has been acquired at dual wavelengths (770 nm and 850 nm). With increase in the concentration of intralipid, an increase in the amplitude of NIRS signal was noted. The response obtained due to 770 nm and 850 nm sources corresponded to lower and upper amplitude respectively.

Research paper thumbnail of Signal Processing through Field Programmable Gate Arrays : Prospects and Challenges

The paper focuses on the use of field programmable gate arrays (FPGA) for signal processing appli... more The paper focuses on the use of field programmable gate arrays (FPGA) for signal processing applications. By allowing designers to create circuit architectures developed for the specific applications, high levels of performance can be achieved using FPGA for many digital signal processing (DSP) applications providing considerable improvements over conventional microprocessor and dedicated DSP processor solutions. A key reason is that an FPGA can side step the classic Von Neumann architecture’s instruction—fetch, load/store bottleneck—found in most DSP. The paper highlights the flexibility offered by FPGA in realizing signal processing architectures and algorithms. The possibility of realizing low power signal processors on FPGA by functional transformation approach has also been discussed. The bottlenecks faced in the state of the art technologies have also been explained.

Research paper thumbnail of Coronary artery disease detection using photoplethysmography

2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)

Research paper thumbnail of Grey-box modeling and hypothesis testing of functional near-infrared spectroscopy-based cerebrovascular reactivity to anodal high-definition tDCS in healthy humans

PLOS Computational Biology

Transcranial direct current stimulation (tDCS) has been shown to evoke hemodynamics response; how... more Transcranial direct current stimulation (tDCS) has been shown to evoke hemodynamics response; however, the mechanisms have not been investigated systematically using systems biology approaches. Our study presents a grey-box linear model that was developed from a physiologically detailed multi-compartmental neurovascular unit model consisting of the vascular smooth muscle, perivascular space, synaptic space, and astrocyte glial cell. Then, model linearization was performed on the physiologically detailed nonlinear model to find appropriate complexity (Akaike information criterion) to fit functional near-infrared spectroscopy (fNIRS) based measure of blood volume changes, called cerebrovascular reactivity (CVR), to high-definition (HD) tDCS. The grey-box linear model was applied on the fNIRS-based CVR during the first 150 seconds of anodal HD-tDCS in eleven healthy humans. The grey-box linear models for each of the four nested pathways starting from tDCS scalp current density that per...

Research paper thumbnail of Non Invasive Estimation of Blood Urea Concentration Using Near Infrared Spectroscopy

International Journal on Smart Sensing and Intelligent Systems

This paper details about the noninvasive estimation of Urea concentration in blood using near inf... more This paper details about the noninvasive estimation of Urea concentration in blood using near infrared spectroscopy (NIRS) and Artificial neural network based prediction model. The absorption spectrum of the urea has been studied experimentally in order to choose the wavelengths of peak absorption. For this purpose, IR absorption spectrum of 0.1M aqueous urea solution has been collected and analyzed in second overtone region of the near-infra red spectra using the Bruker tensor 27 FTIR spectrometer. Based on the theoretical analysis the optimal wavelength of sensor is found to be 995nm for obtaining proper Photo plethysmograph (PPG). The regression analysis has been carried out on PPG signal with the artificial neural networks for obtaining a prediction model for estimating the blood urea concentration. The mean square error of prediction is found to be ± 2.23mg/dL. Index terms: Noninvasive, blood urea, photo plethysmograph, artificial neural network.

Research paper thumbnail of Field Programmable Gate Array Based Embedded System for Non-Invasive Estimation of Hemoglobin in Blood Using Photoplethysmography

International Journal on Smart Sensing and Intelligent Systems

In this paper, a Field Programmable Gate Array (FPGA) based embedded system has been proposed for... more In this paper, a Field Programmable Gate Array (FPGA) based embedded system has been proposed for non-invasive detection of hemoglobin in blood using photoplethysmography. Photoplethysmography (PPG) is a non-invasive and low-cost optical technique that can be used to detect blood volume changes in the micro-vascular bed of tissue. Our investigations revealed that volume of water present in blood considerably affects the reading of the concentration of blood hemoglobin. In our current work, the proposed device is developed with monitoring of PPG waves at three wavelengths so as

Research paper thumbnail of Development of an Fpga Based Smart Diagnostic System for Spirometric Data Processing Applications

International Journal on Smart Sensing and Intelligent Systems

The paper describes the development of an FPGA based fuzzy processing system for pulmonary spirom... more The paper describes the development of an FPGA based fuzzy processing system for pulmonary spirometry applications predicting the approaching obstructive or restrictive pulmonary disorder of the patient before criticality actually occurs. The system employs a smart agent that accepts the Peak Expiratory Flow Rate (PEFR), Forced Expiratory Volume in 1 second (FEV1) and Forced Vital Capacity (FVC) data of patients. In order to speed up the computation process, hybrid parallel data processing architectures with dynamic scheduling mechanism have been employed leading to a speed up of approximately 12 times. The processor implemented on the FPGA can perform fuzzy inferencing at a speed of approximately 5.0 MFLIPS. The whole system is realized on Altera Cyclone EP1K6Q240C8 FPGA chip requiring 5,865 logic blocks. The system has been designed to be inexpensive, portable and user friendly for occupational health care applications in developing countries. Using the system, approaching pulmonary disorder of patients has been predicted with an accuracy of 95.83%.

Research paper thumbnail of Breath Acetone-Based Non-Invasive Detection of Blood Glucose Levels

International Journal on Smart Sensing and Intelligent Systems

There has been a constant demand for the development of non-invasive, sensitive glucose sensor sy... more There has been a constant demand for the development of non-invasive, sensitive glucose sensor system that offers fast and real-time electronic readout of blood glucose levels. In this article, we propose a new system for detecting blood glucose levels by estimating the concentration of acetone in the exhaled breath. A TGS822 tin oxide (SnO 2) sensor has been used to detect the concentration of acetone in the exhaled air. Acetone in exhaled breath showed a correlation with the blood glucose levels. Effects of pressure, temperature and humidity have been considered. Artificial Neural Network (ANN) has been used to extract features from the output waveform of the sensors. The system has been trained and tested with patient data in the blood glucose ranges from 80 mg/dl to 180 mg/dl. Using the proposed system, the blood glucose concentration has been estimated within an error limit of ±7.5 mg/dl.

Research paper thumbnail of Simulation Studies for Non Invasive Classification of Ischemic and Hemorrhagic Stroke using Near Infrared Spectroscopy

Proceedings of the 12th International Joint Conference on Biomedical Engineering Systems and Technologies, 2019

This paper presents an approach to identify and classify the type of stroke, viz ischemic and hem... more This paper presents an approach to identify and classify the type of stroke, viz ischemic and hemorrhagic conditions. Ischemic stroke is caused by the blood clot and plaque present in the blood vessel. Hemorrhagic stroke, on the other hand, occurs when a rupture happens in the cerebrovascular artery or mid-cerebral artery causing impairments in blood flow and hence the supply of oxygen to the cerebral tissues. The current research analyses the blood flow velocity, the pressure profile of blood clot and plaque, and the condition at which ischemic and hemorrhagic stroke occurs. Simulation studies show the pressure on the blood vessel walls under ischemic and hemorrhagic stroke conditions and also that under nominal blood flow velocity the hemorrhage does not occur, but when the velocity is sufficient enough to increase the pressure on the wall, rupture of the mid-cerebral artery takes place. The simulation assumes the blood flow to be laminar, non-Newtonian, viscous, incompressible, and the arterial wall as elastic. Using the simulation model, an approach to classifying ischemic and hemorrhagic stroke using near infrared spectroscopy has been proposed in the paper.

Research paper thumbnail of Design of NIRS Probe Based on Computational Model to Find Out the Optimal Location for Non-Invasive Brain Stimulation

Journal of medical systems, Jan 29, 2018

The paper presents a computational model to analyse the electric field distribution on the cerebr... more The paper presents a computational model to analyse the electric field distribution on the cerebral cortex during high definition transcranial direct current stimulation (HD-tDCS) technique. The current research aims to improve the focality in term of magnitude of electric field (norm [E]) and magnitude of current density (norm [J]) in the gyri and sulci of white matter. The proposed computational model is used to predict the magnitude of current density and magnitude of electric field distribution generated across the target region of cerebral cortex for specific small size 1 × 1 cm multi-electrode HD-tDCS configurations. The current works aims at optimizing the number of electrodes and current density for multielectrode HD-tDCS configuration and weak current intensity is obtained by calculating surface area and penetration depth of target region of cerebral cortex. In terms of surface area and penetration depth 4 × 1 HD-tDCS and 2 mA weak dc current configuration has been selected...

Research paper thumbnail of Near-Infrared Spectroscopy – Electroencephalography-Based Brain-State-Dependent Electrotherapy: A Computational Approach Based on Excitation–Inhibition Balance Hypothesis

Frontiers in Neurology, 2016

FiGUre 1 | electroencephalography (eeG)-functional near-infrared spectroscopy (fnirs) joint-imagi... more FiGUre 1 | electroencephalography (eeG)-functional near-infrared spectroscopy (fnirs) joint-imaging during non-invasive brain stimulation (niBs) and neuromuscular electrical stimulation (nMes). Left panel: experimental setup for the upper limb, Right panel: EEG-fNIRS sensor montage along with NIBS stimulation electrodes [from Ref. (20)]. Figure adapted from Dutta et al. (19).

Research paper thumbnail of FPGA based signal processing: Prospects and Challenges

Research paper thumbnail of Modeling onset effects of transcranial direct current stimulation from NIRS-EEG joint-imaging : an ischemic stroke study

Effects of transcranial direct current stimulation (tDCS) from simultaneous recording of electroe... more Effects of transcranial direct current stimulation (tDCS) from simultaneous recording of electroencephalogram (EEG) and near infra red spectroscopy (NIRS) are presented. Here, tDCS has been shown to modulate cortical neural activity leading to changes in the EEG power spectrum. During neural activity, the electric currents from excitable membranes of brain tissue superimpose at a given location in the extracellular medium and generate a potential, which is referred to as the electroencephalogram (EEG) when recorded from the scalp. This neural activity is closely related, spatially and temporally, to cerebral blood flow (CBF) that supplies glucose via neurovascular coupling. The hemodynamic response to neural activity can be captured by near-infrared spectroscopy (NIRS), which enables continuous monitoring of cerebral oxygenation and blood volume. CBF is increased in brain regions with neural enhanced activity via metabolic coupling mechanisms. SUMMARY Simultaneous recording of NIRS ...

Research paper thumbnail of Performance enhancement in the associative processing of floating point numbers using multi-core superscalar architecture

TENCON 2008 - 2008 IEEE Region 10 Conference, 2008

Page 1. Performance Enhancement in the Associative Processing of Floating Point Numbers using Mul... more Page 1. Performance Enhancement in the Associative Processing of Floating Point Numbers using Multi-core Superscalar Architecture. Subhagya Pani Dept. of Electronics and Communication Engineering, Tezpur University, Tezpur, India Email: subha_pani@rediffmail.com ...

Research paper thumbnail of Fault tolerant design for low power hierarchical search motion estimation algorithms

2011 IEEE/IFIP 19th International Conference on VLSI and System-on-Chip, 2011

Research paper thumbnail of Design, Simulation and Testing of an Optimized Fuzzy Neural Network for Early Criticality Diagnosis

2008 First International Conference on Emerging Trends in Engineering and Technology, 2008

Page 1. Design, Simulation and Testing of an Optimized Fuzzy Neural Network for Early Criticality... more Page 1. Design, Simulation and Testing of an Optimized Fuzzy Neural Network for Early Criticality Diagnosis Shubhajit Roy Chowdhury1, Arijit Biswas2, Rini Chowdhury3 IC Design and Fabrication Centre, Department of Electronics ...

Research paper thumbnail of Non invasive estimation of blood glucose using near infra red spectroscopy and double regression analysis

2013 Seventh International Conference on Sensing Technology (ICST), 2013

A_DSiraci-inis paper presenis a unique lecnnique ior noninvasive estimation ol blood glucose conc... more A_DSiraci-inis paper presenis a unique lecnnique ior noninvasive estimation ol blood glucose concentration using near inlra red spectroscopy. 1 he spectroscopy has been perlormed at the second overtone ol glucose which lalls in the near inlra red region. Ihe near inlra red spectroscopy has been perlormed using transmission pnotopletnsymograpny (li(j). Ine analog Iront end system has been implemented to get tne riG signal at tne near inlra red wavelengths ol 1070nm, 95Unm, 935nm. Ihe II(J signal that has been obtained is processed and double regression analysis is carried out with the artilicial neural network lor estimating the glucose levels. 1 he root mean square error ol the prediction was 5.o4mg/d-L.

Research paper thumbnail of Smart Learning Environments for Teaching Electronics to Students

2013 IEEE Fifth International Conference on Technology for Education (t4e 2013), 2013

The paper presents an alternate approach of teaching electronics by hands on activities instead o... more The paper presents an alternate approach of teaching electronics by hands on activities instead of the conventional approach of classroom lectures and structured lab sessions. The current work applies the notion of Butterfly Model in developing three Learning by Doing (LbD) courses in Electronics viz. Digital System Design Using Verilog, VLSI Architectures, Topics in Embedded Systems. The effectiveness of these courses has been tested in the classroom on a population of 250 students with around 195 people giving positive feedback.

Research paper thumbnail of Maximum power point tracking of partially shaded solar photovoltaic arrays

Solar Energy Materials and Solar Cells, 2010

The paper presents the simulation and hardware implementation of maximum power point (MPP) tracki... more The paper presents the simulation and hardware implementation of maximum power point (MPP) tracking of a partially shaded solar photovoltaic (PV) array using a variant of Particle Swarm Optimization known as Adaptive Perceptive Particle Swarm Optimization (APPSO). Under partially shaded conditions, the photovoltaic (PV) array characteristics get more complex with multiple maxima in the power–voltage characteristic. The paper presents an

Research paper thumbnail of Field Programmable Gate Array Based Fuzzy Neural Signal Processing System for Differential Diagnosis of QRS Complex Tachycardia and Tachyarrhythmia in Noisy ECG Signals

Journal of Medical Systems, 2012

The paper reports of a Field Programmable Gate Array (FPGA) based embedded system for detection o... more The paper reports of a Field Programmable Gate Array (FPGA) based embedded system for detection of QRS complex in a noisy electrocardiogram (ECG) signal and thereafter differential diagnosis of tachycardia and tachyarrhythmia. The QRS complex has been detected after application of entropy measure of fuzziness to build a detection function of ECG signal, which has been previously filtered to remove power line interference and base line wander. Using the detected QRS complexes, differential diagnosis of tachycardia and tachyarrhythmia has been performed. The entire algorithm has been realized in hardware on an FPGA. Using the standard CSE ECG database, the algorithm performed highly effectively. The performance of the algorithm in respect of QRS detection with sensitivity (Se) of 99.74% and accuracy of 99.5% is achieved when tested using single channel ECG with entropy criteria. The performance of the QRS detection system has been compared and found to be better than most of the QRS detection systems available in literature. Using the system, 200 patients have been diagnosed with an accuracy of 98.5%.

Research paper thumbnail of Studies on Rat Brain Phantoms for the Development of Near-Infrared Spectroscopy (NIRS) System

Proceedings of the 11th International Joint Conference on Biomedical Engineering Systems and Technologies, 2018

The present work aims at developing static phantom for rat brain to model the inhomogeneities in ... more The present work aims at developing static phantom for rat brain to model the inhomogeneities in the brain tissues. The inhomogeneities have been modelled by varying the concentration of the fluids that mimic those inhomogeneities. The local variations in various parts of brain can be considered as different concentration of substances and accordingly having different optical attributes. Near-infrared spectroscopy (NIRS) has been used to detect and estimate these local changes that indicate different brain activities. The paper presents the development of static rat brain tissue phantoms and its analysis using a single channel near-infrared spectroscopy (NIRS) system. Homogeneous phantoms have been prepared with different concentrations of agarose and intralipid. For different concentrations, the NIRS signal has been acquired at dual wavelengths (770 nm and 850 nm). With increase in the concentration of intralipid, an increase in the amplitude of NIRS signal was noted. The response obtained due to 770 nm and 850 nm sources corresponded to lower and upper amplitude respectively.

Research paper thumbnail of Signal Processing through Field Programmable Gate Arrays : Prospects and Challenges

The paper focuses on the use of field programmable gate arrays (FPGA) for signal processing appli... more The paper focuses on the use of field programmable gate arrays (FPGA) for signal processing applications. By allowing designers to create circuit architectures developed for the specific applications, high levels of performance can be achieved using FPGA for many digital signal processing (DSP) applications providing considerable improvements over conventional microprocessor and dedicated DSP processor solutions. A key reason is that an FPGA can side step the classic Von Neumann architecture’s instruction—fetch, load/store bottleneck—found in most DSP. The paper highlights the flexibility offered by FPGA in realizing signal processing architectures and algorithms. The possibility of realizing low power signal processors on FPGA by functional transformation approach has also been discussed. The bottlenecks faced in the state of the art technologies have also been explained.

Research paper thumbnail of Coronary artery disease detection using photoplethysmography

2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)

Research paper thumbnail of Grey-box modeling and hypothesis testing of functional near-infrared spectroscopy-based cerebrovascular reactivity to anodal high-definition tDCS in healthy humans

PLOS Computational Biology

Transcranial direct current stimulation (tDCS) has been shown to evoke hemodynamics response; how... more Transcranial direct current stimulation (tDCS) has been shown to evoke hemodynamics response; however, the mechanisms have not been investigated systematically using systems biology approaches. Our study presents a grey-box linear model that was developed from a physiologically detailed multi-compartmental neurovascular unit model consisting of the vascular smooth muscle, perivascular space, synaptic space, and astrocyte glial cell. Then, model linearization was performed on the physiologically detailed nonlinear model to find appropriate complexity (Akaike information criterion) to fit functional near-infrared spectroscopy (fNIRS) based measure of blood volume changes, called cerebrovascular reactivity (CVR), to high-definition (HD) tDCS. The grey-box linear model was applied on the fNIRS-based CVR during the first 150 seconds of anodal HD-tDCS in eleven healthy humans. The grey-box linear models for each of the four nested pathways starting from tDCS scalp current density that per...

Research paper thumbnail of Non Invasive Estimation of Blood Urea Concentration Using Near Infrared Spectroscopy

International Journal on Smart Sensing and Intelligent Systems

This paper details about the noninvasive estimation of Urea concentration in blood using near inf... more This paper details about the noninvasive estimation of Urea concentration in blood using near infrared spectroscopy (NIRS) and Artificial neural network based prediction model. The absorption spectrum of the urea has been studied experimentally in order to choose the wavelengths of peak absorption. For this purpose, IR absorption spectrum of 0.1M aqueous urea solution has been collected and analyzed in second overtone region of the near-infra red spectra using the Bruker tensor 27 FTIR spectrometer. Based on the theoretical analysis the optimal wavelength of sensor is found to be 995nm for obtaining proper Photo plethysmograph (PPG). The regression analysis has been carried out on PPG signal with the artificial neural networks for obtaining a prediction model for estimating the blood urea concentration. The mean square error of prediction is found to be ± 2.23mg/dL. Index terms: Noninvasive, blood urea, photo plethysmograph, artificial neural network.

Research paper thumbnail of Field Programmable Gate Array Based Embedded System for Non-Invasive Estimation of Hemoglobin in Blood Using Photoplethysmography

International Journal on Smart Sensing and Intelligent Systems

In this paper, a Field Programmable Gate Array (FPGA) based embedded system has been proposed for... more In this paper, a Field Programmable Gate Array (FPGA) based embedded system has been proposed for non-invasive detection of hemoglobin in blood using photoplethysmography. Photoplethysmography (PPG) is a non-invasive and low-cost optical technique that can be used to detect blood volume changes in the micro-vascular bed of tissue. Our investigations revealed that volume of water present in blood considerably affects the reading of the concentration of blood hemoglobin. In our current work, the proposed device is developed with monitoring of PPG waves at three wavelengths so as

Research paper thumbnail of Development of an Fpga Based Smart Diagnostic System for Spirometric Data Processing Applications

International Journal on Smart Sensing and Intelligent Systems

The paper describes the development of an FPGA based fuzzy processing system for pulmonary spirom... more The paper describes the development of an FPGA based fuzzy processing system for pulmonary spirometry applications predicting the approaching obstructive or restrictive pulmonary disorder of the patient before criticality actually occurs. The system employs a smart agent that accepts the Peak Expiratory Flow Rate (PEFR), Forced Expiratory Volume in 1 second (FEV1) and Forced Vital Capacity (FVC) data of patients. In order to speed up the computation process, hybrid parallel data processing architectures with dynamic scheduling mechanism have been employed leading to a speed up of approximately 12 times. The processor implemented on the FPGA can perform fuzzy inferencing at a speed of approximately 5.0 MFLIPS. The whole system is realized on Altera Cyclone EP1K6Q240C8 FPGA chip requiring 5,865 logic blocks. The system has been designed to be inexpensive, portable and user friendly for occupational health care applications in developing countries. Using the system, approaching pulmonary disorder of patients has been predicted with an accuracy of 95.83%.

Research paper thumbnail of Breath Acetone-Based Non-Invasive Detection of Blood Glucose Levels

International Journal on Smart Sensing and Intelligent Systems

There has been a constant demand for the development of non-invasive, sensitive glucose sensor sy... more There has been a constant demand for the development of non-invasive, sensitive glucose sensor system that offers fast and real-time electronic readout of blood glucose levels. In this article, we propose a new system for detecting blood glucose levels by estimating the concentration of acetone in the exhaled breath. A TGS822 tin oxide (SnO 2) sensor has been used to detect the concentration of acetone in the exhaled air. Acetone in exhaled breath showed a correlation with the blood glucose levels. Effects of pressure, temperature and humidity have been considered. Artificial Neural Network (ANN) has been used to extract features from the output waveform of the sensors. The system has been trained and tested with patient data in the blood glucose ranges from 80 mg/dl to 180 mg/dl. Using the proposed system, the blood glucose concentration has been estimated within an error limit of ±7.5 mg/dl.