- Aham-Avatar:https://aham-avatar.org/
- Smart City
- Industrial IoT for Energy Efficiency
- Air Quality Monitoring
- Smart Energy
- Drones
- MBZIRC
- Learning to Control
9.Completed Projects
Projects completed in 2020
Projects completed in 2019
Projects completed in 2017
- Developing a framework for using electricity consumption data to drive energy efficiency in the residential sector
- IISc Smart Campus: Closing the loop from network to knowledge
- The Kumb Mela Experiment: Measuring and understanding the dynamics of mankind’s largest crowd
- Study of India-appropriate technology (IoT) solutions for Smart Cities
Projects completed in 2016
- A solar dashboard for India. A cooperative project between ICER & RBCCPS
Principal Investigator: Pradip Dutta (Department of Mechanical Engineering)
Renewable energy is a critical component of India’s energy portfolio given the ever increasing costs and large capital investments required by fossil fuel based generation. With solar power being a key part of this, a wide range of implementations can be expected from roof-top solar implementations, through micro-grids to large scale solar generation facilities. A huge need exists to develop a comprehensive picture of the deployment, operation and output of such systems, and to couple this information with insolation, geological and climatological models to understand the optimum way to grow and manage solar power infrastrusture in India.
The long term goal of this project was to enable the construction of a data gathering capability that can be deployed at the scale necessary to collect this information and to contribute to a total pathway for solar energy deployment in the country. A key component of this pathway was the development of facilities to ensure optimal operation. The project built a scalable measuring and monitoring infrastructure for development of condition based maintenance of photovoltaic generation systems. In addition to the infrastructure, the project developed algorithms tuned to local deployment and operational practices, and to local environments to optimize the operational efficiency of deployed systems such as in rural micro-grids.
The infrastructure and algorithms were tested and validated against a 5MW photovoltaic implementation that was instrumented and operated as part of the project to provide realistic design and operating data. The system will be extended to cover the solar thermal plant at Chellikere. Subsequent to that, the system will be scaled successively to incorporate corporate and facility solar generation and solar generation facilities with the goal of scaling to a comprehensive national facility. The project also examined the feasibility of providing “micro-monitoring” down to the level of individual roof-top solar installations.
- Sensor network based cyber-physical infrastructure for continuous monitoring of water distribution networks
Principal Investigator: M. S. Mohan Kumar (Department of Civil Engineering)
Water distribution systems (WDS) are one of the most critical infrastructures of a nation. It serves drinking water to the millions of people in the country. An accident or damage on the same will risk the life of many people. Hence securing the water network is of utmost importance. Indian water distribution network is under tremendous pressure owing to population growth, ageing infrastructure, poor maintenance, etc. Water supply in most of the Indian cities is intermittent. These factors cause the quality of water in the system to deteriorate to unacceptable levels. Pressure surges due to intermittent water supply cause pipe bursts and leakages which again increases the possibility of contamination (like cross contamination, accidental contamination, etc.)
And this is why the concept of “Smart Water Networks” is important. Such a network is transparent and flexible to meet future challenges and carries out efficient asset management; as a whole it provides a reliable source of water to the consumer. In a smart water network, water quality and quantity data can be collected from the source to the consumer points using sensors, and is transmitted to a central data base where it can be analyzed to understand its change in its hydraulics and quality. Collecting and analyzing water network data enables better understanding of the dynamics of the system and helps in improving system operations and the control on the system. Remote detection of leaks and water losses early detection of contaminant events, real time data acquisition, data analysis, demand forecasting online modelling, energy optimization, sensor placement optimization, real time control, etc. are the key features of a smart water network.
Project Publications
1. | Anjana, G R; Kumar, Sheetal K R; Kumar, Mohan M S; Amrutur, Bharadwaj A particle filter based leak detection technique for water distribution systems Journal Article Procedia Engineering, 119 , pp. 28-34, 2015. @article{Anjana2015, title = {A particle filter based leak detection technique for water distribution systems}, author = {G. R. Anjana and K. R. Sheetal Kumar and M. S. Mohan Kumar and Bharadwaj Amrutur}, url = {http://www.rbccps.org/wp-content/uploads/2018/12/1-s2.0-S1877705815025199-main.pdf}, doi = {10.1016/j.proeng.2015.08.849}, year = {2015}, date = {2015-09-01}, journal = {Procedia Engineering}, volume = {119}, pages = {28-34}, abstract = {Leak detection and localization plays an important role in the efficient management of Water Distribution Systems (WDS), as it will help in reducing water wastage. Automation of WDS (with water quantity and quality sensors) has helped the water authorities around the world to get near real time data of important system parameters. Various models developed on the basis of Extended Kalman Filter (EKF), Nonlinear Kalman Filter etc. have been widely used for leak detection in pipelines. These models are applied on flow, pressure and acoustic signals from the system. But the main disadvantage of most of these models is that, they require the non-linear pipeline model to be linearized. In this paper, we propose the use of a Particle Filter (PF) based technique for the detection of leaks in water pipelines, and the developed model is applied to a real world network in Mandya (Karnataka, India).}, keywords = {}, pubstate = {published}, tppubtype = {article} } Leak detection and localization plays an important role in the efficient management of Water Distribution Systems (WDS), as it will help in reducing water wastage. Automation of WDS (with water quantity and quality sensors) has helped the water authorities around the world to get near real time data of important system parameters. Various models developed on the basis of Extended Kalman Filter (EKF), Nonlinear Kalman Filter etc. have been widely used for leak detection in pipelines. These models are applied on flow, pressure and acoustic signals from the system. But the main disadvantage of most of these models is that, they require the non-linear pipeline model to be linearized. In this paper, we propose the use of a Particle Filter (PF) based technique for the detection of leaks in water pipelines, and the developed model is applied to a real world network in Mandya (Karnataka, India). |
2. | Kudva, Vignesh D; Nayak, Prashanth; Rawat, Alok; Anjana, G R; Kumar, Sheetal K R; Amrutur, Bharadwaj; Kumar, Mohan M S Towards a real-time campus scale water balance monitoring system Conference Proceedings of the 28th International Conference on VLSI Design and 14th International Conference on Embedded Systems, 03.-07.01.15, Bangalore, 2015. @conference{Kudva2015, title = {Towards a real-time campus scale water balance monitoring system}, author = {Vignesh D. Kudva and Prashanth Nayak and Alok Rawat and G. R. Anjana and K. R. Sheetal Kumar and Bharadwaj Amrutur and M. S. Mohan Kumar}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/07031713.pdf}, doi = {10.1109/VLSID.2015.20}, year = {2015}, date = {2015-02-05}, booktitle = {Proceedings of the 28th International Conference on VLSI Design and 14th International Conference on Embedded Systems, 03.-07.01.15, Bangalore}, pages = {87-92}, abstract = {In this paper, we describe the design of a real time water balance monitoring system, suitable for large campuses. The battery operated sensor nodes consist of an ultra-sound level sensor, a 16-bit microcontroller and a sub-gigahertz radio to setup a hub and spoke system. Real time data from the sensors is pushed to a server on the cloud to log as well as perform analytics. Industrial design of the device allows flexible mounting on a variety of tanks. Experimental results from a trial deployment in a medium sized campus are shown to illustrate the usefulness of such a system towards better management of campus water resources.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } In this paper, we describe the design of a real time water balance monitoring system, suitable for large campuses. The battery operated sensor nodes consist of an ultra-sound level sensor, a 16-bit microcontroller and a sub-gigahertz radio to setup a hub and spoke system. Real time data from the sensors is pushed to a server on the cloud to log as well as perform analytics. Industrial design of the device allows flexible mounting on a variety of tanks. Experimental results from a trial deployment in a medium sized campus are shown to illustrate the usefulness of such a system towards better management of campus water resources. |
Projects completed in 2015
- Agricultural automation: Mobile phone based analysis of images of plant leaves to give decision support in agriculture
Principal Investigator: A. G. Ramakrishnan (Department of Computer Science and Automation)
The ultimate goal of agricultural automation is to manage the farm on a site‐by site basis. Traditional soil and plant sampling and analysis methods are very expensive, tedious, and time consuming for obtaining soil and crop parameters on a fine grid and at a short time scale. Sensors capable of gathering information from time to time are needed. They are particularly useful to measure parameters that vary faster in time, such as nitrogen and other nutrient content.
It is a technical solution which will actually be used in agriculture production systems to diagnose the problem, if any and suggest action based on the problem. Such monitoring is important in any production system to ensure quality and quantity in the product. Thus, with the help of suitable colour image processing of the leaf images, we can ensure quality and quantity output in any agriculture production system.
- Cardiac arrhythmias: In silico studies in realistic mathematical models for cardiac tissue
Principal Investigator: Rahul Pandit (Department of Physics)
Cardiac arrhythmias, such as ventricular tachycardia (VT) and ventricular fibrillation (VF), are responsible for approximately 17% of all deaths. Experimental studies suggest that rotating spiral or scroll waves of electrical activation in cardiac tissue are associated with VT, whereas, when these waves break to yield spiral- or scroll-wave turbulence, VT develops into life-threatening VF. In the absence of medical intervention, this makes the heart incapable of pumping blood and a patient dies roughly two-and-a-half minutes after the initiation of VF. Thus, studies of spiral- and scroll-wave dynamics in cardiac tissue pose important challenges for in vivo and in vitro experimental studies and for in silico numerical studies of mathematical models for cardiac tissue. Furthermore, the study of these waves and their eventual elimination from cardiac tissue is a problem of central importance in biomedical engineering and biophysical science.
We have been studying such spiral and scroll waves and their control in state-of-the-art mathematical models for human cardiac tissue; these models include (a) cardiac myocytes, (b) fibroblasts, one of the major non-myocyte cells in heart tissue, (c) cells that display earlyafterdepolarizations (EADs), because they are not normal, and (d) Purkinje fibers, a special conduction system that carries electrical impulses from the bundle of His to the interior of ventricular tissue. Our goal in this project has been the development of low-amplitude defibrillation schemes for the elimination of VT and VF.
Project Publications
1. | Nayak, Alok Ranjan; Panfilov, A V; Pandit, Rahul Spiral-wave dynamics in a mathematical model of human ventricular tissue with myocytes and Purkinje fibers Journal Article Physical Review E, pp. 022405.1-11, 2017. @article{Nayak2017, title = {Spiral-wave dynamics in a mathematical model of human ventricular tissue with myocytes and Purkinje fibers}, author = {Alok Ranjan Nayak and A. V. Panfilov and Rahul Pandit}, url = {http://www.rbccps.org/wp-content/uploads/2018/12/PhysRevE.95.022405.pdf}, doi = {10.1103/PhysRevE.95.022405}, year = {2017}, date = {2017-02-13}, journal = {Physical Review E}, pages = {022405.1-11}, abstract = {We present systematic numerical studies of the possible effects of the coupling of human endocardial and Purkinje cells at cellular and two-dimensional tissue levels. We find that the autorhythmic-activity frequency of the Purkinje cell in a composite decreases with an increase in the coupling strength; this can even eliminate the autorhythmicity. We observe a delay between the beginning of the action potentials of endocardial and Purkinje cells in a composite; such a delay increases as we decrease the diffusive coupling, and eventually a failure of transmission occurs. An increase in the diffusive coupling decreases the slope of the action-potential-duration-restitution curve of an endocardial cell in a composite. By using a minimal model for the Purkinje network, in which we have a two-dimensional, bilayer tissue, with a layer of Purkinje cells on top of a layer of endocardial cells, we can stabilize spiral-wave turbulence; however, for a sparse distribution of Purkinje-ventricular junctions, at which these two layers are coupled, we can also obtain additional focal activity and many complex transient regimes. We also present additional effects resulting from the coupling of Purkinje and endocardial layers and discuss the relation of our results to the studies performed in anatomically accurate models of the Purkinje network.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We present systematic numerical studies of the possible effects of the coupling of human endocardial and Purkinje cells at cellular and two-dimensional tissue levels. We find that the autorhythmic-activity frequency of the Purkinje cell in a composite decreases with an increase in the coupling strength; this can even eliminate the autorhythmicity. We observe a delay between the beginning of the action potentials of endocardial and Purkinje cells in a composite; such a delay increases as we decrease the diffusive coupling, and eventually a failure of transmission occurs. An increase in the diffusive coupling decreases the slope of the action-potential-duration-restitution curve of an endocardial cell in a composite. By using a minimal model for the Purkinje network, in which we have a two-dimensional, bilayer tissue, with a layer of Purkinje cells on top of a layer of endocardial cells, we can stabilize spiral-wave turbulence; however, for a sparse distribution of Purkinje-ventricular junctions, at which these two layers are coupled, we can also obtain additional focal activity and many complex transient regimes. We also present additional effects resulting from the coupling of Purkinje and endocardial layers and discuss the relation of our results to the studies performed in anatomically accurate models of the Purkinje network. |
2. | Zimik, Soling; Nayak, Alok Ranjan; Pandit, Rahul A computational study of the factors influencing the PVC-triggering ability of a cluster of early afterdepolarization-capable myocytes Journal Article PLoS ONE, 10 (12), 2016. @article{Zimik2016, title = {A computational study of the factors influencing the PVC-triggering ability of a cluster of early afterdepolarization-capable myocytes}, author = {Soling Zimik and Alok Ranjan Nayak and Rahul Pandit}, url = {http://www.rbccps.org/wp-content/uploads/2018/11/journal.pone_.0144979.pdf}, doi = {10.1371/journal.pone.0144979}, year = {2016}, date = {2016-12-16}, journal = {PLoS ONE}, volume = {10}, number = {12}, abstract = {Premature ventricular complexes (PVCs), which are abnormal impulse propagations in cardiac tissue, can develop because of various reasons including early afterdepolarizations (EADs). We show how a cluster of EAD-generating cells (EAD clump) can lead to PVCs in a model of cardiac tissue, and also investigate the factors that assist such clumps in triggering PVCs. In particular, we study, through computer simulations, the effects of the following factors on the PVC-triggering ability of an EAD clump: (1) the repolarization reserve (RR) of the EAD cells; (2) the size of the EAD clump; (3) the coupling strength between the EAD cells in the clump; and (4) the presence of fibroblasts in the EAD clump. We find that, although a low value of RR is necessary to generate EADs and hence PVCs, a very low value of RR leads to low-amplitude EAD oscillations that decay with time and do not lead to PVCs. We demonstrate that a certain threshold size of the EAD clump, or a reduction in the coupling strength between the EAD cells, in the clump, is required to trigger PVCs. We illustrate how randomly distributed inexcitable obstacles, which we use to model collagen deposits, affect PVC-triggering by an EAD clump. We show that the gap-junctional coupling of fibroblasts with myocytes can either assist or impede the PVC-triggering ability of an EAD clump, depending on the resting membrane potential of the fibroblasts and the coupling strength between the myocyte and fibroblasts. We also find that the triggering of PVCs by an EAD clump depends sensitively on factors like the pacing cycle length and the distribution pattern of the fibroblasts.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Premature ventricular complexes (PVCs), which are abnormal impulse propagations in cardiac tissue, can develop because of various reasons including early afterdepolarizations (EADs). We show how a cluster of EAD-generating cells (EAD clump) can lead to PVCs in a model of cardiac tissue, and also investigate the factors that assist such clumps in triggering PVCs. In particular, we study, through computer simulations, the effects of the following factors on the PVC-triggering ability of an EAD clump: (1) the repolarization reserve (RR) of the EAD cells; (2) the size of the EAD clump; (3) the coupling strength between the EAD cells in the clump; and (4) the presence of fibroblasts in the EAD clump. We find that, although a low value of RR is necessary to generate EADs and hence PVCs, a very low value of RR leads to low-amplitude EAD oscillations that decay with time and do not lead to PVCs. We demonstrate that a certain threshold size of the EAD clump, or a reduction in the coupling strength between the EAD cells, in the clump, is required to trigger PVCs. We illustrate how randomly distributed inexcitable obstacles, which we use to model collagen deposits, affect PVC-triggering by an EAD clump. We show that the gap-junctional coupling of fibroblasts with myocytes can either assist or impede the PVC-triggering ability of an EAD clump, depending on the resting membrane potential of the fibroblasts and the coupling strength between the myocyte and fibroblasts. We also find that the triggering of PVCs by an EAD clump depends sensitively on factors like the pacing cycle length and the distribution pattern of the fibroblasts. |
3. | Zimik, Soling; Vandersickel, Nele; Nayak, Alok Ranjan; Panfilov, Alexander V; Pandit, Rahul A comparative study of early afterdepolarization-mediated fibrillation in two mathematical models for human ventricular cells Journal Article PLoS ONE, 10 (6), 2015. @article{Zimik2015, title = {A comparative study of early afterdepolarization-mediated fibrillation in two mathematical models for human ventricular cells}, author = {Soling Zimik and Nele Vandersickel and Alok Ranjan Nayak and Alexander V. Panfilov and Rahul Pandit}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/journal.pone_.0130632.pdf}, doi = {10.1371/journal.pone.0130632}, year = {2015}, date = {2015-06-30}, journal = {PLoS ONE}, volume = {10}, number = {6}, abstract = {Early afterdepolarizations (EADs), which are abnormal oscillations of the membrane potential at the plateau phase of an action potential, are implicated in the development of cardiac arrhythmias like Torsade de Pointes. We carry out extensive numerical simulations of the TP06 and ORd mathematical models for human ventricular cells with EADs. We investigate the different regimes in both these models, namely, the parameter regimes where they exhibit (1) a normal action potential (AP) with no EADs, (2) an AP with EADs, and (3) an AP with EADs that does not go back to the resting potential. We also study the dependence of EADs on the rate of at which we pace a cell, with the specific goal of elucidating EADs that are induced by slow or fast rate pacing. In our simulations in two- and three-dimensional domains, in the presence of EADs, we find the following wave types: (A) waves driven by the fast sodium current and the L-type calcium current (Na-Ca-mediated waves); (B) waves driven only by the L-type calcium current (Ca-mediated waves); (C) phase waves, which are pseudo-travelling waves. Furthermore, we compare the wave patterns of the various wave-types (Na-Ca-mediated, Ca-mediated, and phase waves) in both these models. We find that the two models produce qualitatively similar results in terms of exhibiting Na-Ca-mediated wave patterns that are more chaotic than those for the Ca-mediated and phase waves. However, there are quantitative differences in the wave patterns of each wave type. The Na-Ca-mediated waves in the ORd model show short-lived spirals but the TP06 model does not. The TP06 model supports more Ca-mediated spirals than those in the ORd model, and the TP06 model exhibits more phase-wave patterns than does the ORd model.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Early afterdepolarizations (EADs), which are abnormal oscillations of the membrane potential at the plateau phase of an action potential, are implicated in the development of cardiac arrhythmias like Torsade de Pointes. We carry out extensive numerical simulations of the TP06 and ORd mathematical models for human ventricular cells with EADs. We investigate the different regimes in both these models, namely, the parameter regimes where they exhibit (1) a normal action potential (AP) with no EADs, (2) an AP with EADs, and (3) an AP with EADs that does not go back to the resting potential. We also study the dependence of EADs on the rate of at which we pace a cell, with the specific goal of elucidating EADs that are induced by slow or fast rate pacing. In our simulations in two- and three-dimensional domains, in the presence of EADs, we find the following wave types: (A) waves driven by the fast sodium current and the L-type calcium current (Na-Ca-mediated waves); (B) waves driven only by the L-type calcium current (Ca-mediated waves); (C) phase waves, which are pseudo-travelling waves. Furthermore, we compare the wave patterns of the various wave-types (Na-Ca-mediated, Ca-mediated, and phase waves) in both these models. We find that the two models produce qualitatively similar results in terms of exhibiting Na-Ca-mediated wave patterns that are more chaotic than those for the Ca-mediated and phase waves. However, there are quantitative differences in the wave patterns of each wave type. The Na-Ca-mediated waves in the ORd model show short-lived spirals but the TP06 model does not. The TP06 model supports more Ca-mediated spirals than those in the ORd model, and the TP06 model exhibits more phase-wave patterns than does the ORd model. |
4. | Nayak, Alok Ranjan; Pandit, Rahul The effects of fibroblasts on wave dynamics in a mathematical model for human ventricular tissue Conference Proceedings of the 15th International Symposium on Mathematical and Computational Biology (BIOMAT), India, 2015, ISBN: 978-981-4667-93-7. @conference{Nayak2015, title = {The effects of fibroblasts on wave dynamics in a mathematical model for human ventricular tissue}, author = {Alok Ranjan Nayak and Rahul Pandit}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/1601.02397.pdf}, isbn = {978-981-4667-93-7}, year = {2015}, date = {2015-11-07}, booktitle = {Proceedings of the 15th International Symposium on Mathematical and Computational Biology (BIOMAT), India}, pages = {363-378}, abstract = {We present systematic numerical studies of electrical-wave propagation in two-dimensional (2D) and three-dimensional (3D) mathematical models, for human, ventricular tissue with myocyte cells that are attached (a) regularly and (b) randomly to distributed fibroblasts. In both these cases we show that there is a parameter regime in which single rotating spiral- and scroll-wave states (RS) retain their integrity and do not evolve to a state ST that displays spatiotemporal chaos and turbulence. However, in another range of parameters, we observe a transition from ST to RS states in both 2D or 3D domains and for both cases (a) and (b). Our studies show that the ST-RS transition and rotation period of a spiral or scroll wave in the RS state depends on (i) the coupling strength between myocytes and fibroblasts and (ii) the number of fibroblasts attached to myocytes. We conclude that myocyte-fibroblast coupling strength and the number of fibroblasts are more important for the ST-RS transition than the precise way in which fibroblasts are distributed over myocyte tissue.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } We present systematic numerical studies of electrical-wave propagation in two-dimensional (2D) and three-dimensional (3D) mathematical models, for human, ventricular tissue with myocyte cells that are attached (a) regularly and (b) randomly to distributed fibroblasts. In both these cases we show that there is a parameter regime in which single rotating spiral- and scroll-wave states (RS) retain their integrity and do not evolve to a state ST that displays spatiotemporal chaos and turbulence. However, in another range of parameters, we observe a transition from ST to RS states in both 2D or 3D domains and for both cases (a) and (b). Our studies show that the ST-RS transition and rotation period of a spiral or scroll wave in the RS state depends on (i) the coupling strength between myocytes and fibroblasts and (ii) the number of fibroblasts attached to myocytes. We conclude that myocyte-fibroblast coupling strength and the number of fibroblasts are more important for the ST-RS transition than the precise way in which fibroblasts are distributed over myocyte tissue. |
5. | Nayak, Alok Ranjan; Pandit, Rahul Turbulent states and their transitions in mathematical models for ventricular tissue: The effects of random interstitial fibroblasts Journal Article Physical Review E, 92 (3), 2015. @article{Nayak2015b, title = {Turbulent states and their transitions in mathematical models for ventricular tissue: The effects of random interstitial fibroblasts}, author = {Alok Ranjan Nayak and Rahul Pandit}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/PhysRevE.92.032720.pdf}, doi = {10.1103/PhysRevE.92.032720}, year = {2015}, date = {2015-09-21}, journal = {Physical Review E}, volume = {92}, number = {3}, abstract = {We study the dynamical behaviors of two types of spiral- and scroll-wave turbulence states, respectively, in two-dimensional (2D) and three-dimensional (3D) mathematical models, of human, ventricular, myocyte cells that are attached to randomly distributed interstitial fibroblasts; these turbulence states are promoted by (a) the steep slope of the action-potential-duration-restitution (APDR) plot or (b) early afterdepolarizations (EADs). Our single-cell study shows that (1) the myocyte-fibroblast (MF) coupling G_{j} and (2) the number N_{f} of fibroblasts in an MF unit lower the steepness of the APDR slope and eliminate the EAD behaviors of myocytes; we explore the pacing dependence of such EAD suppression. In our 2D simulations, we observe that a spiral-turbulence (ST) state evolves into a state with a single, rotating spiral (RS) if either (a) G_{j} is large or (b) the maximum possible number of fibroblasts per myocyte N_{f}^{max} is large. We also observe that the minimum value of G_{j}, for the transition from the ST to the RS state, decreases as N_{f}^{max} increases. We find that, for the steep-APDR-induced ST state, once the MF coupling suppresses ST, the rotation period of a spiral in the RS state increases as (1) G_{j} increases, with fixed N_{f}^{max}, and (2) N_{f}^{max} increases, with fixed G_{j}. We obtain the boundary between ST and RS stability regions in the N_{f}^{max}-G_{j} plane. In particular, for low values of N_{f}^{max}, the value of G_{j}, at the ST-RS boundary, depends on the realization of the randomly distributed fibroblasts; this dependence decreases as N_{f}^{max} increases. Our 3D studies show a similar transition from scroll-wave turbulence to a single, rotating, scroll-wave state because of the MF coupling. We examine the experimental implications of our study and propose that the suppression (a) of the steep slope of the APDR or (b) EADs can eliminate spiral- and scroll-wave turbulence in heterogeneous cardiac tissue, which has randomly distributed fibroblasts.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We study the dynamical behaviors of two types of spiral- and scroll-wave turbulence states, respectively, in two-dimensional (2D) and three-dimensional (3D) mathematical models, of human, ventricular, myocyte cells that are attached to randomly distributed interstitial fibroblasts; these turbulence states are promoted by (a) the steep slope of the action-potential-duration-restitution (APDR) plot or (b) early afterdepolarizations (EADs). Our single-cell study shows that (1) the myocyte-fibroblast (MF) coupling G_{j} and (2) the number N_{f} of fibroblasts in an MF unit lower the steepness of the APDR slope and eliminate the EAD behaviors of myocytes; we explore the pacing dependence of such EAD suppression. In our 2D simulations, we observe that a spiral-turbulence (ST) state evolves into a state with a single, rotating spiral (RS) if either (a) G_{j} is large or (b) the maximum possible number of fibroblasts per myocyte N_{f}^{max} is large. We also observe that the minimum value of G_{j}, for the transition from the ST to the RS state, decreases as N_{f}^{max} increases. We find that, for the steep-APDR-induced ST state, once the MF coupling suppresses ST, the rotation period of a spiral in the RS state increases as (1) G_{j} increases, with fixed N_{f}^{max}, and (2) N_{f}^{max} increases, with fixed G_{j}. We obtain the boundary between ST and RS stability regions in the N_{f}^{max}-G_{j} plane. In particular, for low values of N_{f}^{max}, the value of G_{j}, at the ST-RS boundary, depends on the realization of the randomly distributed fibroblasts; this dependence decreases as N_{f}^{max} increases. Our 3D studies show a similar transition from scroll-wave turbulence to a single, rotating, scroll-wave state because of the MF coupling. We examine the experimental implications of our study and propose that the suppression (a) of the steep slope of the APDR or (b) EADs can eliminate spiral- and scroll-wave turbulence in heterogeneous cardiac tissue, which has randomly distributed fibroblasts. |
6. | Vandersickel, Nele; Kazbanov, Ivan K; Nuitermans, Anita; Weise, Louis D; Pandit, Rahul; Panfilov, Alexander V A study of early afterdepolarizations in a model for human ventricular tissue Journal Article PLoS ONE, 9 (1), 2014. BibTeX | Links: @article{Vandersickel2014, title = {A study of early afterdepolarizations in a model for human ventricular tissue}, author = {Nele Vandersickel and Ivan K. Kazbanov and Anita Nuitermans and Louis D. Weise and Rahul Pandit and Alexander V. Panfilov}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/journal.pone_.0084595.pdf}, doi = {10.1371/journal.pone.0084595}, year = {2014}, date = {2014-01-10}, journal = {PLoS ONE}, volume = {9}, number = {1}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
7. | Nayak, Alok Ranjan; Pandit, Rahul Spiral-wave dynamics in ionically realistic mathematical models for human ventricular tissue: The effects of periodic deformation Journal Article Frontiers in Physiology, 5 , 2014. @article{Nayak2014, title = {Spiral-wave dynamics in ionically realistic mathematical models for human ventricular tissue: The effects of periodic deformation}, author = {Alok Ranjan Nayak and Rahul Pandit}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/fphys-05-00207.pdf}, doi = {10.3389/fphys.2014.00207}, year = {2014}, date = {2014-06-10}, journal = {Frontiers in Physiology}, volume = {5}, abstract = {We carry out an extensive numerical study of the dynamics of spiral waves of electrical activation, in the presence of periodic deformation (PD) in two-dimensional simulation domains, in the biophysically realistic mathematical models of human ventricular tissue due to (a) ten-Tusscher and Panfilov (the TP06 model) and (b) ten-Tusscher, Noble, Noble, and Panfilov (the TNNP04 model). We first consider simulations in cable-type domains, in which we calculate the conduction velocity θ and the wavelength λ of a plane wave; we show that PD leads to a periodic, spatial modulation of θ and a temporally periodic modulation of λ; both these modulations depend on the amplitude and frequency of the PD. We then examine three types of initial conditions for both TP06 and TNNP04 models and show that the imposition of PD leads to a rich variety of spatiotemporal patterns in the transmembrane potential including states with a single rotating spiral (RS) wave, a spiral-turbulence (ST) state with a single meandering spiral, an ST state with multiple broken spirals, and a state SA in which all spirals are absorbed at the boundaries of our simulation domain. We find, for both TP06 and TNNP04 models, that spiral-wave dynamics depends sensitively on the amplitude and frequency of PD and the initial condition. We examine how these different types of spiral-wave states can be eliminated in the presence of PD by the application of low-amplitude pulses by square- and rectangular-mesh suppression techniques. We suggest specific experiments that can test the results of our simulations.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We carry out an extensive numerical study of the dynamics of spiral waves of electrical activation, in the presence of periodic deformation (PD) in two-dimensional simulation domains, in the biophysically realistic mathematical models of human ventricular tissue due to (a) ten-Tusscher and Panfilov (the TP06 model) and (b) ten-Tusscher, Noble, Noble, and Panfilov (the TNNP04 model). We first consider simulations in cable-type domains, in which we calculate the conduction velocity θ and the wavelength λ of a plane wave; we show that PD leads to a periodic, spatial modulation of θ and a temporally periodic modulation of λ; both these modulations depend on the amplitude and frequency of the PD. We then examine three types of initial conditions for both TP06 and TNNP04 models and show that the imposition of PD leads to a rich variety of spatiotemporal patterns in the transmembrane potential including states with a single rotating spiral (RS) wave, a spiral-turbulence (ST) state with a single meandering spiral, an ST state with multiple broken spirals, and a state SA in which all spirals are absorbed at the boundaries of our simulation domain. We find, for both TP06 and TNNP04 models, that spiral-wave dynamics depends sensitively on the amplitude and frequency of PD and the initial condition. We examine how these different types of spiral-wave states can be eliminated in the presence of PD by the application of low-amplitude pulses by square- and rectangular-mesh suppression techniques. We suggest specific experiments that can test the results of our simulations. |
8. | Majumder, Rupamanjari; Pandit, Rahul; Panfilov, Alexander V Turbulent electrical activity at sharp-edged inexcitable obstacles in a model for human cardiac tissue Journal Article American Journal of Physiology: Heart and Circulatory Physiology, 307 (7), pp. 1024-1035, 2014. @article{Majumder2014, title = {Turbulent electrical activity at sharp-edged inexcitable obstacles in a model for human cardiac tissue}, author = {Rupamanjari Majumder and Rahul Pandit and Alexander V. Panfilov}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/10.10072F978-3-642-37057-1_24.pdf}, doi = {10.1152/ajpheart.00593.2013}, year = {2014}, date = {2014-10-01}, journal = {American Journal of Physiology: Heart and Circulatory Physiology}, volume = {307}, number = {7}, pages = {1024-1035}, abstract = {Wave propagation around various geometric expansions, structures, and obstacles in cardiac tissue may result in the formation of unidirectional block of wave propagation and the onset of reentrant arrhythmias in the heart. Therefore, we investigated the conditions under which reentrant spiral waves can be generated by high-frequency stimulation at sharp-edged obstacles in the ten Tusscher-Noble-Noble-Panfilov (TNNP) ionic model for human cardiac tissue. We show that, in a large range of parameters that account for the conductance of major inward and outward ionic currents of the model [fast inward Na+ current (INa), L—type slow inward Ca2+ current (ICaL), slow delayed-rectifier current (IKs), rapid delayed-rectifier current (IKr), inward rectifier K+ current (IK1)], the critical period necessary for spiral formation is close to the period of a spiral wave rotating in the same tissue. We also show that there is a minimal size of the obstacle for which formation of spirals is possible; this size is ~2.5 cm and decreases with a decrease in the excitability of cardiac tissue. We show that other factors, such as the obstacle thickness and direction of wave propagation in relation to the obstacle, are of secondary importance and affect the conditions for spiral wave initiation only slightly. We also perform studies for obstacle shapes derived from experimental measurements of infarction scars and show that the formation of spiral waves there is facilitated by tissue remodeling around it. Overall, we demonstrate that the formation of reentrant sources around inexcitable obstacles is a potential mechanism for the onset of cardiac arrhythmias in the presence of a fast heart rate.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Wave propagation around various geometric expansions, structures, and obstacles in cardiac tissue may result in the formation of unidirectional block of wave propagation and the onset of reentrant arrhythmias in the heart. Therefore, we investigated the conditions under which reentrant spiral waves can be generated by high-frequency stimulation at sharp-edged obstacles in the ten Tusscher-Noble-Noble-Panfilov (TNNP) ionic model for human cardiac tissue. We show that, in a large range of parameters that account for the conductance of major inward and outward ionic currents of the model [fast inward Na+ current (INa), L—type slow inward Ca2+ current (ICaL), slow delayed-rectifier current (IKs), rapid delayed-rectifier current (IKr), inward rectifier K+ current (IK1)], the critical period necessary for spiral formation is close to the period of a spiral wave rotating in the same tissue. We also show that there is a minimal size of the obstacle for which formation of spirals is possible; this size is ~2.5 cm and decreases with a decrease in the excitability of cardiac tissue. We show that other factors, such as the obstacle thickness and direction of wave propagation in relation to the obstacle, are of secondary importance and affect the conditions for spiral wave initiation only slightly. We also perform studies for obstacle shapes derived from experimental measurements of infarction scars and show that the formation of spiral waves there is facilitated by tissue remodeling around it. Overall, we demonstrate that the formation of reentrant sources around inexcitable obstacles is a potential mechanism for the onset of cardiac arrhythmias in the presence of a fast heart rate. |
9. | Nayak, Alok Ranjan; Shajahan, T K; Panfilov, Alexander V; Pandit, Rahul Spiral-wave dynamics in a mathematical model of human ventricular tissue with myocytes and fibroblasts Journal Article PloS ONE, 8 , 2013. @article{Nayak2013, title = {Spiral-wave dynamics in a mathematical model of human ventricular tissue with myocytes and fibroblasts}, author = {Alok Ranjan Nayak and T. K. Shajahan and Alexander V. Panfilov and Rahul Pandit}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/journal.pone_.0072950.pdf}, doi = {10.1371/journal.pone.0072950}, year = {2013}, date = {2013-09-04}, journal = {PloS ONE}, volume = {8}, abstract = {Cardiac fibroblasts, when coupled functionally with myocytes, can modulate the electrophysiological properties of cardiac tissue. We present systematic numerical studies of such modulation of electrophysiological properties in mathematical models for (a) single myocyte-fibroblast (MF) units and (b) two-dimensional (2D) arrays of such units; our models build on earlier ones and allow for zero-, one-, and two-sided MF couplings. Our studies of MF units elucidate the dependence of the action-potential (AP) morphology on parameters such as , the fibroblast resting-membrane potential, the fibroblast conductance , and the MF gap-junctional coupling . Furthermore, we find that our MF composite can show autorhythmic and oscillatory behaviors in addition to an excitable response. Our 2D studies use (a) both homogeneous and inhomogeneous distributions of fibroblasts, (b) various ranges for parameters such as , and , and (c) intercellular couplings that can be zero-sided, one-sided, and two-sided connections of fibroblasts with myocytes. We show, in particular, that the plane-wave conduction velocity decreases as a function of , for zero-sided and one-sided couplings; however, for two-sided coupling, decreases initially and then increases as a function of , and, eventually, we observe that conduction failure occurs for low values of . In our homogeneous studies, we find that the rotation speed and stability of a spiral wave can be controlled either by controlling or . Our studies with fibroblast inhomogeneities show that a spiral wave can get anchored to a local fibroblast inhomogeneity. We also study the efficacy of a low-amplitude control scheme, which has been suggested for the control of spiral-wave turbulence in mathematical models for cardiac tissue, in our MF model both with and without heterogeneities.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Cardiac fibroblasts, when coupled functionally with myocytes, can modulate the electrophysiological properties of cardiac tissue. We present systematic numerical studies of such modulation of electrophysiological properties in mathematical models for (a) single myocyte-fibroblast (MF) units and (b) two-dimensional (2D) arrays of such units; our models build on earlier ones and allow for zero-, one-, and two-sided MF couplings. Our studies of MF units elucidate the dependence of the action-potential (AP) morphology on parameters such as , the fibroblast resting-membrane potential, the fibroblast conductance , and the MF gap-junctional coupling . Furthermore, we find that our MF composite can show autorhythmic and oscillatory behaviors in addition to an excitable response. Our 2D studies use (a) both homogeneous and inhomogeneous distributions of fibroblasts, (b) various ranges for parameters such as , and , and (c) intercellular couplings that can be zero-sided, one-sided, and two-sided connections of fibroblasts with myocytes. We show, in particular, that the plane-wave conduction velocity decreases as a function of , for zero-sided and one-sided couplings; however, for two-sided coupling, decreases initially and then increases as a function of , and, eventually, we observe that conduction failure occurs for low values of . In our homogeneous studies, we find that the rotation speed and stability of a spiral wave can be controlled either by controlling or . Our studies with fibroblast inhomogeneities show that a spiral wave can get anchored to a local fibroblast inhomogeneity. We also study the efficacy of a low-amplitude control scheme, which has been suggested for the control of spiral-wave turbulence in mathematical models for cardiac tissue, in our MF model both with and without heterogeneities. |
10. | Majumder, Rupamanjari; Nayak, Alok Ranjan; Pandit, Rahul Nonequilibrium arrhythmic states and transitions in a mathematical model for diffuse fibrosis in human cardiac tissue Journal Article PLoS ONE, 2012. @article{Majumder2012, title = {Nonequilibrium arrhythmic states and transitions in a mathematical model for diffuse fibrosis in human cardiac tissue}, author = {Rupamanjari Majumder and Alok Ranjan Nayak and Rahul Pandit}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/journal.pone_.0045040.pdf}, doi = {10.1371/journal.pone.0045040}, year = {2012}, date = {2012-10-08}, journal = {PLoS ONE}, abstract = {We present a comprehensive numerical study of spiral-and scroll-wave dynamics in a state-of-the-art mathematical model for human ventricular tissue with fiber rotation, transmural heterogeneity, myocytes, and fibroblasts. Our mathematical model introduces fibroblasts randomly, to mimic diffuse fibrosis, in the ten Tusscher-Noble-Noble-Panfilov (TNNP) model for human ventricular tissue; the passive fibroblasts in our model do not exhibit an action potential in the absence of coupling with myocytes; and we allow for a coupling between nearby myocytes and fibroblasts. Our study of a single myocyte-fibroblast (MF) composite, with a single myocyte coupled to fibroblasts via a gap-junctional conductance , reveals five qualitatively different responses for this composite. Our investigations of two-dimensional domains with a random distribution of fibroblasts in a myocyte background reveal that, as the percentage of fibroblasts increases, the conduction velocity of a plane wave decreases until there is conduction failure. If we consider spiral-wave dynamics in such a medium we find, in two dimensions, a variety of nonequilibrium states, temporally periodic, quasiperiodic, chaotic, and quiescent, and an intricate sequence of transitions between them; we also study the analogous sequence of transitions for three-dimensional scroll waves in a three-dimensional version of our mathematical model that includes both fiber rotation and transmural heterogeneity. We thus elucidate random-fibrosis-induced nonequilibrium transitions, which lead to conduction block for spiral waves in two dimensions and scroll waves in three dimensions. We explore possible experimental implications of our mathematical and numerical studies for plane-, spiral-, and scroll-wave dynamics in cardiac tissue with fibrosis.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We present a comprehensive numerical study of spiral-and scroll-wave dynamics in a state-of-the-art mathematical model for human ventricular tissue with fiber rotation, transmural heterogeneity, myocytes, and fibroblasts. Our mathematical model introduces fibroblasts randomly, to mimic diffuse fibrosis, in the ten Tusscher-Noble-Noble-Panfilov (TNNP) model for human ventricular tissue; the passive fibroblasts in our model do not exhibit an action potential in the absence of coupling with myocytes; and we allow for a coupling between nearby myocytes and fibroblasts. Our study of a single myocyte-fibroblast (MF) composite, with a single myocyte coupled to fibroblasts via a gap-junctional conductance , reveals five qualitatively different responses for this composite. Our investigations of two-dimensional domains with a random distribution of fibroblasts in a myocyte background reveal that, as the percentage of fibroblasts increases, the conduction velocity of a plane wave decreases until there is conduction failure. If we consider spiral-wave dynamics in such a medium we find, in two dimensions, a variety of nonequilibrium states, temporally periodic, quasiperiodic, chaotic, and quiescent, and an intricate sequence of transitions between them; we also study the analogous sequence of transitions for three-dimensional scroll waves in a three-dimensional version of our mathematical model that includes both fiber rotation and transmural heterogeneity. We thus elucidate random-fibrosis-induced nonequilibrium transitions, which lead to conduction block for spiral waves in two dimensions and scroll waves in three dimensions. We explore possible experimental implications of our mathematical and numerical studies for plane-, spiral-, and scroll-wave dynamics in cardiac tissue with fibrosis. |
- Computer processing of wrist pulse signals acquired using fiber-optic techniques for healthcare appliances
Principal Investigator: Talabattula Srinivas (Department of Electrical Communication Engineering)
Surveys have revealed that cardio vascular diseases are leading the cause of death in the world. From this point of view, a sensor to record the pulse and a method to subsequently process it using computers have great potential in the medical field. The need here was to focus our research on the development of new methods and devices for monitoring and studying cardiovascular diseases. One of the traditional indicators of the condition of the human cardiovascular system is cardio vascular pulsation. Different cardiovascular diseases can be diagnosed depending on the shape, amplitude and rhythm of this pulsation.
The main objective of the project was to develop recording and processing techniques for wrist pulse signals using conventional and fiber optic sensors. Initially the focus was on processing of signals acquired using conventional sensors. Miniature optic sensors were studied subsequently.
- Control and prevention of hospital acquired infections
Principal Investigator: T. V. Prabhakar (Department of Electronic System Engineering)
Infection control measures through sanitation protocols such as hand washing are key to controlling hospital-acquired infections, which is an enormous health hazard to patients as well as the hospital community at large. A simple, low-cost, scalable monitoring solution based on a ‘crowd-sourced’ architecture has been developed to ensure adequate thoroughness of disinfection. A combination of low-cost beacon tags and mobile phones deployed at multiple locations in themedical facility (in the proximity of ICU beds for instance) to compute location information for tracking the movements of hospital personnel, will be used in conjunction with integrated infection control models and state-following algorithms.
Project Publications
1. | Sridhar, Sabarish; Misra, Prasant; Gill, Gurinder Singh; Warrior, Jay CheepSync: A time synchronization service for resource constrained bluetooth low energy advertisers Journal Article IEEE Communications Magazine, 54 (1), pp. 136-143, 2016. @article{Sridhar2016, title = {CheepSync: A time synchronization service for resource constrained bluetooth low energy advertisers}, author = {Sabarish Sridhar and Prasant Misra and Gurinder Singh Gill and Jay Warrior}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/07378439.pdf}, doi = {10.1109/MCOM.2016.7378439}, year = {2016}, date = {2016-01-12}, journal = {IEEE Communications Magazine}, volume = {54}, number = {1}, pages = {136-143}, abstract = {Clock synchronization is highly desirable in distributed systems, including many applications in the Internet of Things and Humans. It improves the efficiency, modularity, and scalability of the system, and optimizes use of event triggers. For IoTH, BLE – a subset of the recent Bluetooth v4.0 stack – provides a low-power and loosely coupled mechanism for sensor data collection with ubiquitous units (e.g., smartphones and tablets) carried by humans. This fundamental design paradigm of BLE is enabled by a range of broadcast advertising modes. While its operational benefits are numerous, the lack of a common time reference in the broadcast mode of BLE has been a fundamental limitation. This article presents and describes CheepSync, a time synchronization service for BLE advertisers, especially tailored for applications requiring high time precision on resource constrained BLE platforms. Designed on top of the existing Bluetooth v4.0 standard, the CheepSync framework utilizes low-level timestamping and comprehensive error compensation mechanisms for overcoming uncertainties in message transmission, clock drift, and other system-specific constraints. CheepSync was implemented on custom designed nRF24Cheep beacon platforms (as broadcasters) and commercial off-the-shelf Android ported smartphones (as passive listeners). We demonstrate the efficacy of CheepSync by numerous empirical evaluations in a variety of experimental setups, and show that its average (single-hop) time synchronization accuracy is in the 10 μs range.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Clock synchronization is highly desirable in distributed systems, including many applications in the Internet of Things and Humans. It improves the efficiency, modularity, and scalability of the system, and optimizes use of event triggers. For IoTH, BLE – a subset of the recent Bluetooth v4.0 stack – provides a low-power and loosely coupled mechanism for sensor data collection with ubiquitous units (e.g., smartphones and tablets) carried by humans. This fundamental design paradigm of BLE is enabled by a range of broadcast advertising modes. While its operational benefits are numerous, the lack of a common time reference in the broadcast mode of BLE has been a fundamental limitation. This article presents and describes CheepSync, a time synchronization service for BLE advertisers, especially tailored for applications requiring high time precision on resource constrained BLE platforms. Designed on top of the existing Bluetooth v4.0 standard, the CheepSync framework utilizes low-level timestamping and comprehensive error compensation mechanisms for overcoming uncertainties in message transmission, clock drift, and other system-specific constraints. CheepSync was implemented on custom designed nRF24Cheep beacon platforms (as broadcasters) and commercial off-the-shelf Android ported smartphones (as passive listeners). We demonstrate the efficacy of CheepSync by numerous empirical evaluations in a variety of experimental setups, and show that its average (single-hop) time synchronization accuracy is in the 10 μs range. |
2. | Venugopalakrishna, Y R; Murthy, Chandra R; Misra, Prasant; Warrior, Jay A column matching based algorithm for target self-localization using beacon nodes Conference Proceedings of the 14th International Conference on Information Processing in Sensor Networks (IPSN), USA, 2015. @conference{Venugopalakrishna2015, title = {A column matching based algorithm for target self-localization using beacon nodes}, author = {Y. R. Venugopalakrishna and Chandra R. Murthy and Prasant Misra and Jay Warrior}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/p380-venugopalakrishna.pdf}, doi = {10.1145/2737095.2742935}, year = {2015}, date = {2015-04-16}, booktitle = {Proceedings of the 14th International Conference on Information Processing in Sensor Networks (IPSN), USA}, pages = {380-381}, abstract = {In this work, an algorithm is proposed for self-localization of a target node using power measurements from beacon nodes transmitting from known locations. The geographical area is overlaid with a virtual grid, and the problem is treated as one of testing overlapping subsets of grid cells for the presence of the target node. The proposed algorithm is validated both by Monte Carlo simulations as well as using experimental data collected from commercially-off-the-shelf bluetooth low energy (BLE) beacon nodes.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } In this work, an algorithm is proposed for self-localization of a target node using power measurements from beacon nodes transmitting from known locations. The geographical area is overlaid with a virtual grid, and the problem is treated as one of testing overlapping subsets of grid cells for the presence of the target node. The proposed algorithm is validated both by Monte Carlo simulations as well as using experimental data collected from commercially-off-the-shelf bluetooth low energy (BLE) beacon nodes. |
3. | Sridhar, Sabarish; Misra, Prasant; Warrior, Jay CheepSync: A time synchronization service for resource constrained bluetooth low energy advertisers Conference Proceedings of the 14th International Conference on Information Processing in Sensor Networks (IPSN), USA, 2015. @conference{Sridhar2015, title = {CheepSync: A time synchronization service for resource constrained bluetooth low energy advertisers}, author = {Sabarish Sridhar and Prasant Misra and Jay Warrior}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/p364-sridhar.pdf}, doi = {10.1145/2737095.2742925}, year = {2015}, date = {2015-04-16}, booktitle = {Proceedings of the 14th International Conference on Information Processing in Sensor Networks (IPSN), USA}, pages = {364-365}, abstract = {Clock synchronization is highly desirable in distributed systems, including many applications in the Internet of Things and Humans (IoTH). For IoTH, Bluetooth Low Energy (BLE) – a subset of the recent Bluetooth v4:0 stack – provides a low-power and loosely coupled mechanism for sensor data collection with ubiquitous units (e.g., smartphones and tablets) carried by humans. This fundamental design paradigm of BLE is enabled by a range of broadcast advertising modes. While its operational benefits are numerous, the lack of a common time reference in the broadcast mode of BLE has been a fundamental limitation. This work presents and describes CheepSync: a time synchronization service architecture for BLE advertisers. We implement CheepSync on custom designed nRF24Cheep beacon platforms (as broadcasters) and commercial off-the-shelf Android ported smartphones (as passive listeners); and show that the average (single hop) time synchronization accuracy is in the 10 μs range.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } Clock synchronization is highly desirable in distributed systems, including many applications in the Internet of Things and Humans (IoTH). For IoTH, Bluetooth Low Energy (BLE) – a subset of the recent Bluetooth v4:0 stack – provides a low-power and loosely coupled mechanism for sensor data collection with ubiquitous units (e.g., smartphones and tablets) carried by humans. This fundamental design paradigm of BLE is enabled by a range of broadcast advertising modes. While its operational benefits are numerous, the lack of a common time reference in the broadcast mode of BLE has been a fundamental limitation. This work presents and describes CheepSync: a time synchronization service architecture for BLE advertisers. We implement CheepSync on custom designed nRF24Cheep beacon platforms (as broadcasters) and commercial off-the-shelf Android ported smartphones (as passive listeners); and show that the average (single hop) time synchronization accuracy is in the 10 μs range. |
4. | Misra, Prasant; Rajaraman, Vasanth; Aishwarya, S N; Dwivedi, Bharat; Warrior, Jay CleanHands: An integrated monitoring system for control of hospital acquired infections Conference Proceedings of the 14th International Conference on Information Processing in Sensor Networks (IPSN), USA, 2015. @conference{Misra2015, title = {CleanHands: An integrated monitoring system for control of hospital acquired infections}, author = {Prasant Misra and Vasanth Rajaraman and S. N. Aishwarya and Bharat Dwivedi and Jay Warrior}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/p348-misra.pdf}, doi = {10.1145/2737095.2742928}, year = {2015}, date = {2015-04-16}, booktitle = {Proceedings of the 14th International Conference on Information Processing in Sensor Networks (IPSN), USA}, pages = {348-349}, abstract = {A leading cause of mortality of hospitalized patients are hospital acquired infections (HAI). Unclean hands of healthcare personnel (HCP) are the most common factor contributing to HAI, but their strict compliance to hand hygiene protocols is difficult to supervise. In this work, we propose CleanHands: a simple, low-cost and scalable monitoring and alerting system to ensure adequate thoroughness of disinfection. CleanHands uses a combination of low-cost Bluetooth low energy (BLE) beacon tags and mobile phones for HCP tracking. It integrates infection control models and state-following algorithms for alarming in the event of noncompliance to hand hygiene. Our preliminary experiments in a mockup, small scale intensive care unit (ICU) facility shows promising results with less than 5% false positives.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } A leading cause of mortality of hospitalized patients are hospital acquired infections (HAI). Unclean hands of healthcare personnel (HCP) are the most common factor contributing to HAI, but their strict compliance to hand hygiene protocols is difficult to supervise. In this work, we propose CleanHands: a simple, low-cost and scalable monitoring and alerting system to ensure adequate thoroughness of disinfection. CleanHands uses a combination of low-cost Bluetooth low energy (BLE) beacon tags and mobile phones for HCP tracking. It integrates infection control models and state-following algorithms for alarming in the event of noncompliance to hand hygiene. Our preliminary experiments in a mockup, small scale intensive care unit (ICU) facility shows promising results with less than 5% false positives. |
5. | Rajaraman, Vasanth; Misra, Prasant; Dhotrad, Kumaresh; Warrior, Jay Enabling Plug-n-Play for the Internet of Things with self describing devices Conference Proceedings of the 14th International Conference on Information Processing in Sensor Networks (IPSN), USA, 2015. @conference{Rajaraman2015, title = {Enabling Plug-n-Play for the Internet of Things with self describing devices}, author = {Vasanth Rajaraman and Prasant Misra and Kumaresh Dhotrad and Jay Warrior}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/p374-rajaraman.pdf}, doi = {10.1145/2737095.2742927}, year = {2015}, date = {2015-04-16}, booktitle = {Proceedings of the 14th International Conference on Information Processing in Sensor Networks (IPSN), USA}, pages = {374-375}, abstract = {The primal problem with the Internet of Things is the lack of interoperability at various levels, and more predominately at the device level. While there exists multitude of platforms from multiple manufacturers, the existing ecosystem still remains highly closed. In this work, we propose SNaaS or Sensor/Network as a Service: a service layer that enables the creation of the plug-n-play infrastructure, across platforms from multiple vendors, necessary for interoperability and successful deployment of large-scale systems. We present the design and implementation of SNaaS, along with preliminary microbenchmarks.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } The primal problem with the Internet of Things is the lack of interoperability at various levels, and more predominately at the device level. While there exists multitude of platforms from multiple manufacturers, the existing ecosystem still remains highly closed. In this work, we propose SNaaS or Sensor/Network as a Service: a service layer that enables the creation of the plug-n-play infrastructure, across platforms from multiple vendors, necessary for interoperability and successful deployment of large-scale systems. We present the design and implementation of SNaaS, along with preliminary microbenchmarks. |
6. | Govindarajan, Nithyashri; Simmhan, Yogesh; Jamadagni, Nitin; Misra, Prasant Event processing across edge and the cloud for Internet of Things applications Conference Proceedings of the 20th International Conference on Management of Data (COMAD), 17.-19.12.14, Mumbai, 2014. @conference{Govindarajan2014, title = {Event processing across edge and the cloud for Internet of Things applications}, author = {Nithyashri Govindarajan and Yogesh Simmhan and Nitin Jamadagni and Prasant Misra}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/p101-govindarajan.pdf}, year = {2014}, date = {2014-12-17}, booktitle = {Proceedings of the 20th International Conference on Management of Data (COMAD), 17.-19.12.14, Mumbai}, pages = {101-104}, abstract = {The rapid growth of sensing devices has opened up complex event processing (CEP) for real-time analytics in Internet of Things (IoT) Applications. While CEP has traditionally been centralized, the increasing capabilities of edge devices like smart phones, and the operational needs of low latency and privacy makes it desirable to use both edge and the Cloud for distributed CEP, the former often serving as event sources. This paper motivates the need for real-time analytics across edge and the Cloud, formalizes an optimization problem for bi-partitioning a CEP query pipeline based on IoT application needs, and proposes an initial solution.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } The rapid growth of sensing devices has opened up complex event processing (CEP) for real-time analytics in Internet of Things (IoT) Applications. While CEP has traditionally been centralized, the increasing capabilities of edge devices like smart phones, and the operational needs of low latency and privacy makes it desirable to use both edge and the Cloud for distributed CEP, the former often serving as event sources. This paper motivates the need for real-time analytics across edge and the Cloud, formalizes an optimization problem for bi-partitioning a CEP query pipeline based on IoT application needs, and proposes an initial solution. |
Patent Application
Warrior, Jay; Prabhakar, T. V.: Variable range beacon, Indian Patent Application No. 5029/CHE/2014
- Cyber surgery and remote patient care
Principal Investigator: Ashitava Ghosal (Department of Mechanical Engineering)
Endoscopy is extensively used in examination and diagnosis of diseases in the gastrointestinal (GI) tract. Current endoscopy practice is primarily related to imaging, diagnosis and to a small extent in retrieving tissue for biopsy. There is an acute need of training for endoscopy on virtual (simulator) systems before an endoscopist can be allowed to examine patients. Although a few such systems exist, they are typically very expensive, and all do not give realistic virtual environment, i.e. do not provide haptics/force feedback and the surgical tools for minimally invasive surgery (MIS) cannot be positioned very accurately. The development of actuated end-effectors for use in endoscopes and MIS, imaging, visualization, and mechanical characterization of the GI tract and assisted identification and close examination of abnormal parts have been goals of this project. This project addressed these issues in terms of basic research and developing cost-effective laboratory prototypes.
Project Publications
1. | Ashwin K P; Ghosal, Ashitava Static Modeling of Miniaturized Pneumatic Artificial Muscles, Kinematic Analysis, and Experiments on an Endoscopic End-Effector Journal Article IEEE/ASME Transactions on Mechatronics, 24 (4), pp. 1429-1439, 2019. @article{Ashwin2019b, title = {Static Modeling of Miniaturized Pneumatic Artificial Muscles, Kinematic Analysis, and Experiments on an Endoscopic End-Effector}, author = {Ashwin, K P; Ghosal, Ashitava}, url = {http://10.0.54.4/wp-content/uploads/2019/10/Static-Modeling-of-Miniaturized-Pneumatic-artificial-muscles…..pdf}, doi = {10.1109/TMECH.2019.2916783}, year = {2019}, date = {2019-05-14}, journal = { IEEE/ASME Transactions on Mechatronics}, volume = {24}, number = {4}, pages = {1429-1439}, abstract = {In this paper, we present the design, development, modeling, and experimental validation of an endoscopic attachment that can be used to independently position an endoscopic catheter tip at a desired location. Three miniaturized pneumatic artificial muscles (MPAMs) are used in a flexible endoscopic attachment, each MPAM is of 1.2 mm diameter and 45 mm in length and placed approximately 120 degrees apart within a pair of concentric springs. Pressurizing one or more MPAMs allows the tip to be positioned in a workspace, which is approximately a hemispherical section of radius 45 mm. We present a new and improved theoretical model for pressure-deformation relationship of a MPAM using static equations of a pressurized thick cylinder and constraints due to the braids. Comparison with existing models show that the proposed model performs better and the errors predicted by the model are less than 5% with experiments. A new forward kinematic model relating the position and orientation of the tip of the end-effector with changes in MPAM lengths is developed. Finally, we present experimental results conducted on a prototype endoscopic attachment and show that our model could predict the pose of the end-effector with a maximum error of 2 ± 1 mm.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this paper, we present the design, development, modeling, and experimental validation of an endoscopic attachment that can be used to independently position an endoscopic catheter tip at a desired location. Three miniaturized pneumatic artificial muscles (MPAMs) are used in a flexible endoscopic attachment, each MPAM is of 1.2 mm diameter and 45 mm in length and placed approximately 120 degrees apart within a pair of concentric springs. Pressurizing one or more MPAMs allows the tip to be positioned in a workspace, which is approximately a hemispherical section of radius 45 mm. We present a new and improved theoretical model for pressure-deformation relationship of a MPAM using static equations of a pressurized thick cylinder and constraints due to the braids. Comparison with existing models show that the proposed model performs better and the errors predicted by the model are less than 5% with experiments. A new forward kinematic model relating the position and orientation of the tip of the end-effector with changes in MPAM lengths is developed. Finally, we present experimental results conducted on a prototype endoscopic attachment and show that our model could predict the pose of the end-effector with a maximum error of 2 ± 1 mm. |
2. | Chakravarthy, Shanthanu; Balakuntala, Mythra V S; Rao, Ashwin M; Thakur, Ravi Kumar; Ananthasuresh, G K Development of an integrated haptic system for simulating upper gastrointestinal endoscopy Journal Article Mechatronics, 56 (12), pp. 115-131, 2018. @article{Chakravarthy2018, title = {Development of an integrated haptic system for simulating upper gastrointestinal endoscopy}, author = {Shanthanu Chakravarthy and Mythra V. S. Balakuntala and Ashwin M. Rao and Ravi Kumar Thakur and G. K. Ananthasuresh}, url = {http://www.rbccps.org/wp-content/uploads/2018/12/1-s2.0-S0957415818301636-main.pdf}, doi = {10.1016/j.mechatronics.2018.10.006}, year = {2018}, date = {2018-11-12}, journal = {Mechatronics}, volume = {56}, number = {12}, pages = {115-131}, abstract = {Virtual reality together with haptics offers immersive and flexible platforms for training doctors in medical procedures. In this paper, we present mechanical design, control, integration, and user-studies of a virtual reality-based haptic simulator for Upper Gastrointestinal (GI) endoscopy. The design overcomes some of the limitations of the existing systems. First, there is an extra degree of freedom for simulating junctions controlled by sphincter muscles in addition to translational and rotational degrees of freedom along and about the axis of the endoscope-tube. Second, the force-feedback is continuous over a longer range in all three degrees of freedom. Third, multiple insertions and removals of the tube are made possible with a magnetically actuated snap-fit mechanism. A Dynamics-based feed-forward control algorithm is developed and characterized for fidelity and transparency. The system provides continuous force up to 11 N in the axial direction and continuous torque up to 255 mN.m about the axial direction. The haptic device is integrated with a physics-based Virtual Reality (VR) interface. Furthermore, an immersion study was conducted using the integrated system with a cohort of novice and experienced clinicians. The haptic response and virtual model were rated high and improvements were suggested for graphical visualization and physical arrangement.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Virtual reality together with haptics offers immersive and flexible platforms for training doctors in medical procedures. In this paper, we present mechanical design, control, integration, and user-studies of a virtual reality-based haptic simulator for Upper Gastrointestinal (GI) endoscopy. The design overcomes some of the limitations of the existing systems. First, there is an extra degree of freedom for simulating junctions controlled by sphincter muscles in addition to translational and rotational degrees of freedom along and about the axis of the endoscope-tube. Second, the force-feedback is continuous over a longer range in all three degrees of freedom. Third, multiple insertions and removals of the tube are made possible with a magnetically actuated snap-fit mechanism. A Dynamics-based feed-forward control algorithm is developed and characterized for fidelity and transparency. The system provides continuous force up to 11 N in the axial direction and continuous torque up to 255 mN.m about the axial direction. The haptic device is integrated with a physics-based Virtual Reality (VR) interface. Furthermore, an immersion study was conducted using the integrated system with a cohort of novice and experienced clinicians. The haptic response and virtual model were rated high and improvements were suggested for graphical visualization and physical arrangement. |
3. | Sekuboyina, Anjany Kumar; Devarakonda, Surya Teja; Seelamantula, Chandra Sekhar A convolutional neural network approach for abnormality detection in wireless capsule endoscopy Conference Proceedings of the 2017 IEEE International Symposium on Biomedical Imaging, 18.-21.04.2017, Melbourne (Australia), 2017. @conference{Sekuboyina2017, title = {A convolutional neural network approach for abnormality detection in wireless capsule endoscopy}, author = {Anjany Kumar Sekuboyina and Surya Teja Devarakonda and Chandra Sekhar Seelamantula}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/07950698.pdf}, doi = {10.1109/ISBI.2017.7950698}, year = {2017}, date = {2017-06-19}, booktitle = {Proceedings of the 2017 IEEE International Symposium on Biomedical Imaging, 18.-21.04.2017, Melbourne (Australia)}, pages = {1057-1060}, abstract = {In wireless capsule endoscopy (WCE), a swallowable miniature optical endoscope is used to transmit color images of the gastrointestinal tract. However, the number of images transmitted is large, taking a significant amount of the medical expert’s time to review the scan. In this paper, we propose a technique to automate the abnormality detection in WCE images. We split the image into several patches and extract features pertaining to each block using a convolutional neural network (CNN) to increase their generality while overcoming the drawbacks of manually crafted features. We intend to exploit the importance of color information for the task. Experiments are performed to determine the optimal color space components for feature extraction and classifier design. We ob- tained an area under receiver-operating-characteristic (ROC) curve of approximately 0.8 on a dataset containing multiple abnormalities, namely, aphthae, bleeding, chylous cysts, lymphangiectasias, polypoids, stenoses, ulcers, and villous oedema.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } In wireless capsule endoscopy (WCE), a swallowable miniature optical endoscope is used to transmit color images of the gastrointestinal tract. However, the number of images transmitted is large, taking a significant amount of the medical expert’s time to review the scan. In this paper, we propose a technique to automate the abnormality detection in WCE images. We split the image into several patches and extract features pertaining to each block using a convolutional neural network (CNN) to increase their generality while overcoming the drawbacks of manually crafted features. We intend to exploit the importance of color information for the task. Experiments are performed to determine the optimal color space components for feature extraction and classifier design. We ob- tained an area under receiver-operating-characteristic (ROC) curve of approximately 0.8 on a dataset containing multiple abnormalities, namely, aphthae, bleeding, chylous cysts, lymphangiectasias, polypoids, stenoses, ulcers, and villous oedema. |
4. | Shivashankar, Nithin; Natarajan, Vijay Efficient software for programmable visual analysis using Morse-Smale complexes Conference Proceedings of the 2015 Conference on Topological Methods in Data Analysis and Visualisation (TopoInVis), 20.-22.05.15, Annweiler (Germany) , 2017. @conference{Shivashankar2017, title = {Efficient software for programmable visual analysis using Morse-Smale complexes}, author = {Nithin Shivashankar and Vijay Natarajan}, doi = {10.1007/978-3-319-44684-4_19}, year = {2017}, date = {2017-06-03}, booktitle = {Proceedings of the 2015 Conference on Topological Methods in Data Analysis and Visualisation (TopoInVis), 20.-22.05.15, Annweiler (Germany) }, pages = {337-331}, abstract = {The Morse-Smale complex is a topological data structure that represents the behavior of the gradient of an input scalar field. Recent years have witnessed a significant number of applications that use this data structure for visualization and analysis of data from various scientific domains. However, these applications have required significant expertise in the implementation of algorithms. This potentially makes such analysis inaccessible to a large audience. In this paper we present open source software modules for the computation, analysis, and visualization of scientific data using the Morse-Smale complex. The modules, named pymstri and pyms3d, are intended for domains represented using 2D triangle meshes and 3D structured grids respectively. The software is designed to significantly reduce the effort required to use Morse-Smale complex based analysis. Also, the software leverages modern multi-core CPU and GPU architectures for computational efficiency. We demonstrate the usefulness via a case study to visually analyze and interactively segment the eye of the Hurricane Isabel simulation dataset. In particular, we highlight the ability to couple the visual analysis and the computation with ParaView, a popular general purpose visualization tool. The code is available at the project website http://vgl.csa.iisc.ac.in/mscomplex.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } The Morse-Smale complex is a topological data structure that represents the behavior of the gradient of an input scalar field. Recent years have witnessed a significant number of applications that use this data structure for visualization and analysis of data from various scientific domains. However, these applications have required significant expertise in the implementation of algorithms. This potentially makes such analysis inaccessible to a large audience. In this paper we present open source software modules for the computation, analysis, and visualization of scientific data using the Morse-Smale complex. The modules, named pymstri and pyms3d, are intended for domains represented using 2D triangle meshes and 3D structured grids respectively. The software is designed to significantly reduce the effort required to use Morse-Smale complex based analysis. Also, the software leverages modern multi-core CPU and GPU architectures for computational efficiency. We demonstrate the usefulness via a case study to visually analyze and interactively segment the eye of the Hurricane Isabel simulation dataset. In particular, we highlight the ability to couple the visual analysis and the computation with ParaView, a popular general purpose visualization tool. The code is available at the project website http://vgl.csa.iisc.ac.in/mscomplex. |
5. | Kumar, Harish J R; Seelamantula, Chandra Sekhar; Narayan, Nikhil S; Marziliano, Pina Automatic segmentation of common carotid artery in transverse mode ultrasound images Conference Proceedings of the 2016 IEEE International Conference on Image Processing (ICIP), 25.-28.09.16, Phoenix, 2016. @conference{Kumar2016c, title = {Automatic segmentation of common carotid artery in transverse mode ultrasound images}, author = {J. R. Harish Kumar and Chandra Sekhar Seelamantula and Nikhil S. Narayan and Pina Marziliano}, url = {http://www.rbccps.org/wp-content/uploads/2018/12/07532385.pdf}, doi = {10.1109/ICIP.2016.7532385}, year = {2016}, date = {2016-08-19}, booktitle = {Proceedings of the 2016 IEEE International Conference on Image Processing (ICIP), 25.-28.09.16, Phoenix}, abstract = {We consider the problem of carotid artery segmentation and develop an automated outlining technique based on the active disc formalism that we recently introduced. The outlining problem is posed as one of optimization of a locally defined contrast function with respect to the affine transformation parameters that characterize the active disc. It turns out that standard techniques based on gradient-descent minimization can be used to carry out the optimization, although more sophisticated optimizers could also be deployed. For the initialization, we use a matched filter with a template size chosen based on an estimate of the average size of the carotid artery. We report results of experimental validation on Brno university’s signal processing (SP) lab database, which contains 971 transverse mode ultrasound images of the carotid artery. The images in the database are manually annotated using a circle with center and radius explicitly specified in pixels, which serves as the reference. The circular annotation is also a good match with the active disc template considered in this paper. The proposed method results in an average detection accuracy of 95.5% and an average Dice similarity measure of 87.36% and takes only a few seconds of processing time per image. Comparisons with other state-of-the-art techniques are also reported.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } We consider the problem of carotid artery segmentation and develop an automated outlining technique based on the active disc formalism that we recently introduced. The outlining problem is posed as one of optimization of a locally defined contrast function with respect to the affine transformation parameters that characterize the active disc. It turns out that standard techniques based on gradient-descent minimization can be used to carry out the optimization, although more sophisticated optimizers could also be deployed. For the initialization, we use a matched filter with a template size chosen based on an estimate of the average size of the carotid artery. We report results of experimental validation on Brno university’s signal processing (SP) lab database, which contains 971 transverse mode ultrasound images of the carotid artery. The images in the database are manually annotated using a circle with center and radius explicitly specified in pixels, which serves as the reference. The circular annotation is also a good match with the active disc template considered in this paper. The proposed method results in an average detection accuracy of 95.5% and an average Dice similarity measure of 87.36% and takes only a few seconds of processing time per image. Comparisons with other state-of-the-art techniques are also reported. |
6. | Singh, Puneet; Jana, Sumitash; Ghosal, Ashitava; Murthy, Aditya Exploration of joint redundancy but not task space variability facilitates supervised motor learning Journal Article Proceedings of the National Academy of Sciences of the United States of America, 113 (50), pp. 14414-14419, 2016. @article{Singh2016, title = {Exploration of joint redundancy but not task space variability facilitates supervised motor learning}, author = {Puneet Singh and Sumitash Jana and Ashitava Ghosal and Aditya Murthy}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/PNAS-2016-Singh-14414-9.pdf}, doi = {10.1073/pnas.1613383113}, year = {2016}, date = {2016-10-27}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {113}, number = {50}, pages = {14414-14419}, abstract = {Theories of reinforcement learning claim that motor variability helps in motor learning and are supported by recent experimental work. In contrast, theories of motor control propose that variability is noise that needs to be suppressed. We attempt to reconcile these apparent contradictory positions. Using the formulation of the unconstrained manifold hypothesis, we show that motor variability has two components – a part arising out of the redundancy that does not affect task-space and another component related to task-space variability. We show that the motor variability component resulting from the redundancy determines both dynamic and kinematic learning ability across subjects without affecting task-space variability.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Theories of reinforcement learning claim that motor variability helps in motor learning and are supported by recent experimental work. In contrast, theories of motor control propose that variability is noise that needs to be suppressed. We attempt to reconcile these apparent contradictory positions. Using the formulation of the unconstrained manifold hypothesis, we show that motor variability has two components – a part arising out of the redundancy that does not affect task-space and another component related to task-space variability. We show that the motor variability component resulting from the redundancy determines both dynamic and kinematic learning ability across subjects without affecting task-space variability. |
7. | Katti, Anirudh N; Chakravarthy, Shanthanu; Ananthasuresh, G K A haptic device for entry into the throat in endoscopy Conference Proceedings of the 2015 TrC-IFToMM Symposium on the Theory of Machines and Mechanisms, Turkey, 2015. @conference{Katti2015, title = {A haptic device for entry into the throat in endoscopy}, author = {Anirudh N. Katti and Shanthanu Chakravarthy and G. K. Ananthasuresh}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/198.pdf}, year = {2015}, date = {2015-06-17}, booktitle = {Proceedings of the 2015 TrC-IFToMM Symposium on the Theory of Machines and Mechanisms, Turkey}, pages = {232-328}, abstract = {One of the principal uses of an endoscopy simulator is training personnel who perform endoscopy. The most important skill to be acquired in Gastrointestinal (GI) endoscopy is precise and safe insertion of the endoscope through the throat by avoiding damage and causing minimal discomfort to the patient. In this work, we focus on this aspect and present a haptic device with which novice endoscopists can be trained. The device consists of a single degree-of-freedom compliant mechanism that emulates controlled and responsive circularly shaped opening. The mechanism is designed in view of the anatomy of the throat and the special maneuver required for intubation of the endoscope. The device is actuated by a direct-drive motor controlled by a dSPACE controller. The haptic device is developed to be integrated with the upper GI tract simulator developed by our group. Any standard endoscope can be used in this system. In this paper, we describe the design, fabrication, and experimentation with the throat-haptic device and its integration into the simulator system.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } One of the principal uses of an endoscopy simulator is training personnel who perform endoscopy. The most important skill to be acquired in Gastrointestinal (GI) endoscopy is precise and safe insertion of the endoscope through the throat by avoiding damage and causing minimal discomfort to the patient. In this work, we focus on this aspect and present a haptic device with which novice endoscopists can be trained. The device consists of a single degree-of-freedom compliant mechanism that emulates controlled and responsive circularly shaped opening. The mechanism is designed in view of the anatomy of the throat and the special maneuver required for intubation of the endoscope. The device is actuated by a direct-drive motor controlled by a dSPACE controller. The haptic device is developed to be integrated with the upper GI tract simulator developed by our group. Any standard endoscope can be used in this system. In this paper, we describe the design, fabrication, and experimentation with the throat-haptic device and its integration into the simulator system. |
8. | Acharya, Aditya; Natarajan, Vijay A parallel and memory efficient algorithm for constructing the contour tree Conference Proceedings of the 2015 IEEE Pacific Visualization Symposium (PacificVis), China, 2015. @conference{Acharya2015, title = {A parallel and memory efficient algorithm for constructing the contour tree}, author = {Aditya Acharya and Vijay Natarajan}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/07156387.pdf}, doi = {10.1109/PACIFICVIS.2015.7156387}, year = {2015}, date = {2015-04-17}, booktitle = {Proceedings of the 2015 IEEE Pacific Visualization Symposium (PacificVis), China}, pages = {271-278}, abstract = {The contour tree is a topological structure associated with a scalar function that tracks the connectivity of the evolving level sets of the function. It supports intuitive and interactive visual exploration and analysis of the scalar function. This paper describes a fast, parallel, and memory efficient algorithm for constructing the contour tree of a scalar function on shared memory systems. Comparisons with existing implementations show significant improvement in both the running time and the memory expended. The proposed algorithm is particularly suited for large datasets that do not fit in memory. For example, the contour tree for a scalar function defined on a 8.6 billion vertex domain (2048×2048×2048 volume data) can be efficiently constructed using less than 10GB of memory.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } The contour tree is a topological structure associated with a scalar function that tracks the connectivity of the evolving level sets of the function. It supports intuitive and interactive visual exploration and analysis of the scalar function. This paper describes a fast, parallel, and memory efficient algorithm for constructing the contour tree of a scalar function on shared memory systems. Comparisons with existing implementations show significant improvement in both the running time and the memory expended. The proposed algorithm is particularly suited for large datasets that do not fit in memory. For example, the contour tree for a scalar function defined on a 8.6 billion vertex domain (2048×2048×2048 volume data) can be efficiently constructed using less than 10GB of memory. |
9. | Venkatesh, Manasij; Seelamantula, Chandra Sekhar Directional bilateral filters Conference Proceedings of the 39th IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), Italy, 2015. @conference{Venkatesh2015, title = {Directional bilateral filters}, author = {Manasij Venkatesh and Chandra Sekhar Seelamantula}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/07178236.pdf}, doi = {10.1109/ICASSP.2015.7178236}, year = {2015}, date = {2015-04-24}, booktitle = {Proceedings of the 39th IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), Italy}, pages = {1578-1582}, abstract = {We propose a bilateral filter with a locally controlled domain kernel for directional edge-preserving smoothing. Traditional bilateral filters use a range kernel, which is responsible for edge preservation, and a fixed domain kernel that performs smoothing. Our intuition is that orientation and anisotropy of image structures should be incorporated into the domain kernel while smoothing. For this purpose, we employ an oriented Gaussian domain kernel locally controlled by a structure tensor. The oriented domain kernel combined with a range kernel forms the directional bilateral filter. The two kernels assist each other in effectively suppressing the influence of the outliers while smoothing. To find the optimal parameters of the directional bilateral filter, we propose the use of Stein’s unbiased risk estimate (SURE). We test the capabilities of the kernels separately as well as together, first on synthetic images, and then on real endoscopic images. The directional bilateral filter has better denoising performance than the Gaussian bilateral filter at various noise levels in terms of peak signal-to-noise ratio (PSNR).}, keywords = {}, pubstate = {published}, tppubtype = {conference} } We propose a bilateral filter with a locally controlled domain kernel for directional edge-preserving smoothing. Traditional bilateral filters use a range kernel, which is responsible for edge preservation, and a fixed domain kernel that performs smoothing. Our intuition is that orientation and anisotropy of image structures should be incorporated into the domain kernel while smoothing. For this purpose, we employ an oriented Gaussian domain kernel locally controlled by a structure tensor. The oriented domain kernel combined with a range kernel forms the directional bilateral filter. The two kernels assist each other in effectively suppressing the influence of the outliers while smoothing. To find the optimal parameters of the directional bilateral filter, we propose the use of Stein’s unbiased risk estimate (SURE). We test the capabilities of the kernels separately as well as together, first on synthetic images, and then on real endoscopic images. The directional bilateral filter has better denoising performance than the Gaussian bilateral filter at various noise levels in terms of peak signal-to-noise ratio (PSNR). |
10. | Narayanan, Vidya; Thomas, Dilip Mathew; Natarajan, Vijay Distance between extremum graphs Conference Proceedings of the 2015 IEEE Pacific Visualization Symposium (PacificVis), China, 2015. @conference{Narayanan2015, title = {Distance between extremum graphs}, author = {Vidya Narayanan and Dilip Mathew Thomas and Vijay Natarajan}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/07156386.pdf}, doi = {10.1109/PACIFICVIS.2015.7156386}, year = {2015}, date = {2015-04-17}, booktitle = {Proceedings of the 2015 IEEE Pacific Visualization Symposium (PacificVis), China}, journal = {Proceedings of the IEEE Pacific Visualization Symposium (PacificVis 2015)}, pages = {263-270}, abstract = {Scientific phenomena are often studied through collections of related scalar fields generated from different observations of the same phenomenon. Exploration of such data requires a robust distance measure to compare scalar fields for tasks such as identifying key events and establishing correspondence between features in the data. Towards this goal, we propose a topological data structure called the complete extremum graph and define a distance measure on it for comparing scalar fields in a feature-aware manner. We design an algorithm for computing the distance and show its applications in analysing time varying data.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } Scientific phenomena are often studied through collections of related scalar fields generated from different observations of the same phenomenon. Exploration of such data requires a robust distance measure to compare scalar fields for tasks such as identifying key events and establishing correspondence between features in the data. Towards this goal, we propose a topological data structure called the complete extremum graph and define a distance measure on it for comparing scalar fields in a feature-aware manner. We design an algorithm for computing the distance and show its applications in analysing time varying data. |
Patent Applications
Chakravarthy, Shanthanu; Rao, Ashwin M.; Ananthasuresh, G. K.: A haptic device for endoscopy, Indian Patent Application No. 3439/CHE/2014 (26.02.16), PTC Application No. PCT/IB2015/055251
Katti, Anirudh; Chakravarthy, Shanthanu; Ananthasuresh, G. K.: A single-layer compliant mechanism for reversible motion between circumferential and radial directions, Indian Patent Application No. 1248/CHE/2015
- Fiber Bragg Grating sensors for distributed bio-chemical sensing
Principal Investigator: Manoj Varma (Centre for Nano Science and Engineering)
The main objective of this project has been the development of a personal health diagnostic device based on a distributed sensor based on an array of individual sensing elements that have been functionalized in different ways (polyelectrolyte coatings with multiple receptors). The resulting platform is label-free, i.e, no fluorophores are required to generate the desired signal resulting in simplified sensing protocols. The sensing element is an etched Fiber Bragg grating (FBG) which is a type of distributed Bragg reflector along a short segment of an optical fiber whose outer cladding has been removed for higher sensitivity. This approach of exploiting the large multiplexing capability of FBGs coupled with Remote Neonatal Monitoring and Intervention Fiber Bragg Grating Sensors for distributed bio-chemical sensing two novel techniques for incorporating a wide spectrum of functionalization receptors is able to yield high specificities. Recently, this platform has been used for detecting various biomarkers for diagnosing cardiovascular diseases.
Project Publications
1. | Kumar, Saurabh; Amrutur, Bharadwaj; Asokan, Sundarrajan Evaluation of Fiber Bragg Grating sensor interrogation using InGaAs linear detector arrays and Gaussian approximation on embedded hardware Journal Article Review of Scientific Instruments, 89 (2), 2018. @article{Kumar2018b, title = {Evaluation of Fiber Bragg Grating sensor interrogation using InGaAs linear detector arrays and Gaussian approximation on embedded hardware}, author = {Saurabh Kumar and Bharadwaj Amrutur and Sundarrajan Asokan}, url = {http://www.rbccps.org/wp-content/uploads/2018/06/1.5022548.pdf}, doi = {10.1063/1.5022548}, year = {2018}, date = {2018-02-28}, journal = {Review of Scientific Instruments}, volume = {89}, number = {2}, abstract = {Fiber Bragg Grating (FBG) sensors have become popular for applications related to structural health monitoring, biomedical engineering, and robotics. However, for successful large scale adoption, FBG interrogation systems are as important as sensor characteristics. Apart from accuracy, the required number of FBG sensors per fiber and the distance between the device in which the sensors are used and the interrogation system also influence the selection of the interrogation technique. For several measurement devices developed for applications in biomedical engineering and robotics, only a few sensors per fiber are required and the device is close to the interrogation system. For these applications, interrogation systems based on InGaAs linear detector arrays provide a good choice. However, their resolution is dependent on the algorithms used for curve fitting. In this work, a detailed analysis of the choice of algorithm using the Gaussian approximation for the FBG spectrum and the number of pixels used for curve fitting on the errors is provided. The points where the maximum errors occur have been identified. All comparisons for wavelength shift detection have been made against another interrogation system based on the tunable swept laser. It has been shown that maximum errors occur when the wavelength shift is such that one new pixel is included for curve fitting. It has also been shown that an algorithm with lower computation cost compared to the more popular methods using iterative non-linear least squares estimation can be used without leading to the loss of accuracy. The algorithm has been implemented on embedded hardware, and a speed-up of approximately six times has been observed.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Fiber Bragg Grating (FBG) sensors have become popular for applications related to structural health monitoring, biomedical engineering, and robotics. However, for successful large scale adoption, FBG interrogation systems are as important as sensor characteristics. Apart from accuracy, the required number of FBG sensors per fiber and the distance between the device in which the sensors are used and the interrogation system also influence the selection of the interrogation technique. For several measurement devices developed for applications in biomedical engineering and robotics, only a few sensors per fiber are required and the device is close to the interrogation system. For these applications, interrogation systems based on InGaAs linear detector arrays provide a good choice. However, their resolution is dependent on the algorithms used for curve fitting. In this work, a detailed analysis of the choice of algorithm using the Gaussian approximation for the FBG spectrum and the number of pixels used for curve fitting on the errors is provided. The points where the maximum errors occur have been identified. All comparisons for wavelength shift detection have been made against another interrogation system based on the tunable swept laser. It has been shown that maximum errors occur when the wavelength shift is such that one new pixel is included for curve fitting. It has also been shown that an algorithm with lower computation cost compared to the more popular methods using iterative non-linear least squares estimation can be used without leading to the loss of accuracy. The algorithm has been implemented on embedded hardware, and a speed-up of approximately six times has been observed. |
2. | Umesh, Sharath; Kumar, Resmi Ravi; Pant, Shweta; Asokan, Sundarrajan Fiber Bragg Grating based two-dimensional accelerometer Conference Proceedings of the 2015 International Conference on Smart Sensors and Systems (IC-SSS), 21.-23.12.15, Bangalore, 2017. @conference{Umesh2017, title = {Fiber Bragg Grating based two-dimensional accelerometer}, author = {Sharath Umesh and Resmi Ravi Kumar and Shweta Pant and Sundarrajan Asokan}, url = {http://www.rbccps.org/wp-content/uploads/2018/12/07873608.pdf}, doi = {10.1109/SMARTSENS.2015.7873608}, year = {2017}, date = {2017-03-09}, booktitle = {Proceedings of the 2015 International Conference on Smart Sensors and Systems (IC-SSS), 21.-23.12.15, Bangalore}, abstract = {Fiber Bragg Grating (FBG) sensors have become one of the most widely used sensors in the recent times for a variety of applications in the fields of aerospace, civil, automotive, etc. It has been recently realized that FBG based accelerometer’s performance meets and/or exceeds that of traditional sensors. The present work is about the development of a novel, real-time, dynamic two dimensional Accelerometer employing FBG sensors. The proposed FBG Accelerometer works on the principle of inertial mass acceleration which in turn produces strain variations on the adjoining cantilevers, obtained using the FBG sensors bonded over it. The proposed device facilitates compact size and low fabricating cost along with the inherent advantages of FBG sensor, making it an effective device for measuring acceleration.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } Fiber Bragg Grating (FBG) sensors have become one of the most widely used sensors in the recent times for a variety of applications in the fields of aerospace, civil, automotive, etc. It has been recently realized that FBG based accelerometer’s performance meets and/or exceeds that of traditional sensors. The present work is about the development of a novel, real-time, dynamic two dimensional Accelerometer employing FBG sensors. The proposed FBG Accelerometer works on the principle of inertial mass acceleration which in turn produces strain variations on the adjoining cantilevers, obtained using the FBG sensors bonded over it. The proposed device facilitates compact size and low fabricating cost along with the inherent advantages of FBG sensor, making it an effective device for measuring acceleration. |
3. | Chetana, K; Prasad, Arudi Guru S; Omkar, Subbarama N; Asokan, Sundarrajan Fiber bragg grating sensor based device for simultaneous measurement of respiratory and cardiac activities Journal Article Journal of Biophotonics, 10 (2), pp. 278-285, 2017. @article{Chetana2017, title = {Fiber bragg grating sensor based device for simultaneous measurement of respiratory and cardiac activities}, author = {K. Chetana and Arudi S. Guru Prasad and Subbarama N. Omkar and Sundarrajan Asokan}, url = {http://www.rbccps.org/wp-content/uploads/2018/12/Chethana_et_al-2016-Journal_of_Biophotonics.pdf}, doi = {10.1002/jbio.201500268}, year = {2017}, date = {2017-02-28}, journal = {Journal of Biophotonics}, volume = {10}, number = {2}, pages = {278-285}, abstract = {This paper reports a novel optical ballistocardiography technique, which is non‐invasive, for the simultaneous measurement of cardiac and respiratory activities using a Fiber Bragg Grating Heart Beat Device (FBGHBD). The unique design of FBGHBD offers additional capabilities such as monitoring nascent morphology of cardiac and breathing activity, heart rate variability, heart beat rhythm, etc., which can assist in early clinical diagnosis of many conditions associated with heart and lung malfunctioning. The results obtained from the FBGHBD positioned around the pulmonic area on the chest have been evaluated against an electronic stethoscope which detects and records sound pulses originated from the cardiac activity. In order to evaluate the performance of the FBGHBD, quantitative and qualitative studies have been carried out and the results are found to be reliable and accurate, validating its potential as a standalone medical diagnostic device. The developed FBGHBD is simple in design, robust, portable, EMI proof, shock proof and non‐electric in its operation which are desired features for any clinical diagnostic tool used in hospital environment. }, keywords = {}, pubstate = {published}, tppubtype = {article} } This paper reports a novel optical ballistocardiography technique, which is non‐invasive, for the simultaneous measurement of cardiac and respiratory activities using a Fiber Bragg Grating Heart Beat Device (FBGHBD). The unique design of FBGHBD offers additional capabilities such as monitoring nascent morphology of cardiac and breathing activity, heart rate variability, heart beat rhythm, etc., which can assist in early clinical diagnosis of many conditions associated with heart and lung malfunctioning. The results obtained from the FBGHBD positioned around the pulmonic area on the chest have been evaluated against an electronic stethoscope which detects and records sound pulses originated from the cardiac activity. In order to evaluate the performance of the FBGHBD, quantitative and qualitative studies have been carried out and the results are found to be reliable and accurate, validating its potential as a standalone medical diagnostic device. The developed FBGHBD is simple in design, robust, portable, EMI proof, shock proof and non‐electric in its operation which are desired features for any clinical diagnostic tool used in hospital environment. |
4. | Kumar, Saurabh; Shrikanth, Venkoba; Amrutur, Bharadwaj; Asokan, Sundarrajan; Bobji, Musuvathi S Detecting stages of needle penetration into tissues through force estimation at needle tip using Fiber Bragg grating sensors Journal Article Journal of Biomedical Optics, 21 (12), 2016. @article{Kumar2016, title = {Detecting stages of needle penetration into tissues through force estimation at needle tip using Fiber Bragg grating sensors}, author = {Saurabh Kumar and Venkoba Shrikanth and Bharadwaj Amrutur and Sundarrajan Asokan and Musuvathi S. Bobji}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/127009.pdf}, doi = {doi:10.1117/1.JBO.21.12.127009}, year = {2016}, date = {2016-12-30}, journal = {Journal of Biomedical Optics}, volume = {21}, number = {12}, abstract = {Several medical procedures involve the use of needles. The advent of robotic and robot assisted procedures requires dynamic estimation of the needle tip location during insertion for use in both assistive systems as well as for automatic control. Most prior studies have focused on the maneuvering of solid flexible needles using external force measurements at the base of the needle holder. However, hollow needles are used in several procedures and measurements of forces in proximity of such needles can eliminate the need for estimating frictional forces that have high variations. These measurements are also significant for endoscopic procedures in which measurement of forces at the needle holder base is difficult. Fiber Bragg grating sensors, due to their small size, inert nature, and multiplexing capability, provide a good option for this purpose. Force measurements have been undertaken during needle insertion into tissue mimicking phantoms made of polydimethylsiloxane as well as chicken tissue using an 18-G needle instrumented with FBG sensors. The results obtained show that it is possible to estimate the different stages of needle penetration including partial rupture, which is significant for procedures in which precise estimation of needle tip position inside the organ or tissue is required.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Several medical procedures involve the use of needles. The advent of robotic and robot assisted procedures requires dynamic estimation of the needle tip location during insertion for use in both assistive systems as well as for automatic control. Most prior studies have focused on the maneuvering of solid flexible needles using external force measurements at the base of the needle holder. However, hollow needles are used in several procedures and measurements of forces in proximity of such needles can eliminate the need for estimating frictional forces that have high variations. These measurements are also significant for endoscopic procedures in which measurement of forces at the needle holder base is difficult. Fiber Bragg grating sensors, due to their small size, inert nature, and multiplexing capability, provide a good option for this purpose. Force measurements have been undertaken during needle insertion into tissue mimicking phantoms made of polydimethylsiloxane as well as chicken tissue using an 18-G needle instrumented with FBG sensors. The results obtained show that it is possible to estimate the different stages of needle penetration including partial rupture, which is significant for procedures in which precise estimation of needle tip position inside the organ or tissue is required. |
5. | Sridevi, S; Vasu, K S; Asokan, Sundarrajan; Sood, Ajay K Enhanced strain and temperature sensing by reduced graphene oxide coated etched fiber Bragg gratings Journal Article Optics Letters, 41 (11), pp. 2604-2607, 2016. @article{Sridevi2016, title = {Enhanced strain and temperature sensing by reduced graphene oxide coated etched fiber Bragg gratings}, author = {S. Sridevi and K. S. Vasu and Sundarrajan Asokan and Ajay K. Sood}, doi = {10.1364/OL.41.002604}, year = {2016}, date = {2016-05-26}, journal = {Optics Letters}, volume = {41}, number = {11}, pages = {2604-2607}, abstract = {This Letter reports on an etched fiber Bragg grating (eFBG) sensor coated with reduced graphene oxide (RGO) having enhanced sensitivity for physical parameters such as strain and temperature. The synergetic effect of the changes in grating pitch and refractive index of RGO with change in temperature or strain enhances the shift in Bragg wavelength (??). The RGO-coated eFBG sensors exhibit a strain sensitivity of 5.5 pm/μϵ (∼5 times that of bare fiber Bragg gratings) and temperature sensitivity of 33 pm/°C (∼3 times that of bare fiber Bragg gratings). The resolutions of ∼1 μ? and ∼0.3°C have been obtained for strain and temperature respectively, using RGO-coated eFBG sensors.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This Letter reports on an etched fiber Bragg grating (eFBG) sensor coated with reduced graphene oxide (RGO) having enhanced sensitivity for physical parameters such as strain and temperature. The synergetic effect of the changes in grating pitch and refractive index of RGO with change in temperature or strain enhances the shift in Bragg wavelength (??). The RGO-coated eFBG sensors exhibit a strain sensitivity of 5.5 pm/μϵ (∼5 times that of bare fiber Bragg gratings) and temperature sensitivity of 33 pm/°C (∼3 times that of bare fiber Bragg gratings). The resolutions of ∼1 μ? and ∼0.3°C have been obtained for strain and temperature respectively, using RGO-coated eFBG sensors. |
6. | Umesh, Sharath; Ambastha, Shikha; Asokan, Sundarrajan Fiber Bragg Grating tilt meter Conference Proceedings of the 2nd International Conference on Emerging Electronics (ICEE), 03.-06.12.14, Bangalore, 2015. @conference{Umesh2015b, title = {Fiber Bragg Grating tilt meter}, author = {Sharath Umesh and Shikha Ambastha and Sundarrajan Asokan}, url = {http://www.rbccps.org/wp-content/uploads/2018/12/07151142.pdf}, doi = {10.1109/ICEmElec.2014.7151142}, year = {2015}, date = {2015-07-09}, booktitle = {Proceedings of the 2nd International Conference on Emerging Electronics (ICEE), 03.-06.12.14, Bangalore}, abstract = {In this paper, we propose a novel methodology of real time dynamic tilt monitoring through the designed and developed Fiber Bragg Grating Tilt Meter (FBGTM). Based on the volumetric water pressure exerted from inside the chamber on the diaphragm over which the FBG sensor is bonded, the tilt angle of FBGTM can be estimated. An inclination platform is constructed to test the designed FBGTM in conjunction with a commercial inclinometer. The results obtained from both sensor methodologies are in good agreement with each other.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } In this paper, we propose a novel methodology of real time dynamic tilt monitoring through the designed and developed Fiber Bragg Grating Tilt Meter (FBGTM). Based on the volumetric water pressure exerted from inside the chamber on the diaphragm over which the FBG sensor is bonded, the tilt angle of FBGTM can be estimated. An inclination platform is constructed to test the designed FBGTM in conjunction with a commercial inclinometer. The results obtained from both sensor methodologies are in good agreement with each other. |
7. | Chetana, K; Prasad, Arudi Guru S; Vikranth, H N; Varun, H; Omkar, Subbarama N; Asokan, Sundarrajan Fiber Braggs Grating sensor based instrumentation to evaluate postural balance and stability on an unstable platform Journal Article International Journal of Mechanical, Aerospace, Industrial, Mechatronic and Manufacturing Engineering, 9 (1), pp. 96-101, 2015. @article{Chetana2015, title = {Fiber Braggs Grating sensor based instrumentation to evaluate postural balance and stability on an unstable platform}, author = {K. Chetana and Arudi S. Guru Prasad and H. N. Vikranth and H. Varun and Subbarama N. Omkar and Sundarrajan Asokan}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/pdf.pdf}, year = {2015}, date = {2015-01-31}, journal = {International Journal of Mechanical, Aerospace, Industrial, Mechatronic and Manufacturing Engineering}, volume = {9}, number = {1}, pages = {96-101}, abstract = {This paper describes a novel application of Fiber Braggs Grating (FBG) sensors in the assessment of human postural stability and balance on an unstable platform. In this work, FBG sensor Stability Analyzing Device (FBGSAD) is developed for measurement of plantar strain to assess the postural stability of subjects on unstable platforms during different stances in eyes open and eyes closed conditions on a rocker board. The studies are validated by comparing the Centre of Gravity (CG) variations measured on the lumbar vertebra of subjects using a commercial accelerometer. The results obtained from the developed FBGSAD depict qualitative similarities with the data recorded by commercial accelerometer. The advantage of the FBGSAD is that it measures simultaneously plantar strain distribution and postural stability of the subject along with its inherent benefits like non-requirement of energizing voltage to the sensor, electromagnetic immunity and simple design which suits its applicability in biomechanical applications. The developed FBGSAD can serve as a tool/yardstick to mitigate space motion sickness, identify individuals who are susceptible to falls and to qualify subjects for balance and stability, which are important factors in the selection of certain unique professionals such as aircraft pilots, astronauts, cosmonauts etc.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This paper describes a novel application of Fiber Braggs Grating (FBG) sensors in the assessment of human postural stability and balance on an unstable platform. In this work, FBG sensor Stability Analyzing Device (FBGSAD) is developed for measurement of plantar strain to assess the postural stability of subjects on unstable platforms during different stances in eyes open and eyes closed conditions on a rocker board. The studies are validated by comparing the Centre of Gravity (CG) variations measured on the lumbar vertebra of subjects using a commercial accelerometer. The results obtained from the developed FBGSAD depict qualitative similarities with the data recorded by commercial accelerometer. The advantage of the FBGSAD is that it measures simultaneously plantar strain distribution and postural stability of the subject along with its inherent benefits like non-requirement of energizing voltage to the sensor, electromagnetic immunity and simple design which suits its applicability in biomechanical applications. The developed FBGSAD can serve as a tool/yardstick to mitigate space motion sickness, identify individuals who are susceptible to falls and to qualify subjects for balance and stability, which are important factors in the selection of certain unique professionals such as aircraft pilots, astronauts, cosmonauts etc. |
8. | Sridevi, S; Vasu, K S; Sampath, S; Asokan, Sundarrajan; Sood, Ajay K Optical detection of glucose and glycated hemoglobin using etched fiber Bragg gratings coated with functionalized reduced graphene oxide Journal Article Journal of Biophotonics, 9 (7), pp. 760-769, 2015. @article{Sridevi2015, title = {Optical detection of glucose and glycated hemoglobin using etched fiber Bragg gratings coated with functionalized reduced graphene oxide}, author = {S. Sridevi and K. S. Vasu and S. Sampath and Sundarrajan Asokan and Ajay K. Sood}, doi = {10.1002/jbio.201580156}, year = {2015}, date = {2015-08-12}, journal = {Journal of Biophotonics}, volume = {9}, number = {7}, pages = {760-769}, abstract = {An enhanced optical detection of D-glucose and glycated hemoglobin (HbA1c ) has been established in this study using etched fiber Bragg gratings (eFBG) coated with aminophenylboronic acid (APBA)-functionalized reduced graphene oxide (RGO). The read out, namely the shift in Bragg wavelength (ΔλB ) is highly sensitive to changes that occur due to the adsorption of glucose (or HbA1c ) molecules on the eFBG sensor coated with APBA-RGO complex through a five-membered cyclic ester bond formation between glucose and APBA molecules. A limit of detection of 1 nM is achieved with a linear range of detection from 1 nM to 10 mM in the case of D-glucose detection experiments. For HbA1c , a linear range of detection varying from 86 nM to 0.23 mM is achieved. The observation of only 4 pm (picometer) change in ΔλB even for the 10 mM lactose solution confirms the specificity of the APBA-RGO complex coated eFBG sensors to glucose molecules.}, keywords = {}, pubstate = {published}, tppubtype = {article} } An enhanced optical detection of D-glucose and glycated hemoglobin (HbA1c ) has been established in this study using etched fiber Bragg gratings (eFBG) coated with aminophenylboronic acid (APBA)-functionalized reduced graphene oxide (RGO). The read out, namely the shift in Bragg wavelength (ΔλB ) is highly sensitive to changes that occur due to the adsorption of glucose (or HbA1c ) molecules on the eFBG sensor coated with APBA-RGO complex through a five-membered cyclic ester bond formation between glucose and APBA molecules. A limit of detection of 1 nM is achieved with a linear range of detection from 1 nM to 10 mM in the case of D-glucose detection experiments. For HbA1c , a linear range of detection varying from 86 nM to 0.23 mM is achieved. The observation of only 4 pm (picometer) change in ΔλB even for the 10 mM lactose solution confirms the specificity of the APBA-RGO complex coated eFBG sensors to glucose molecules. |
9. | Umesh, Sharath; Padme, Srivani; Ambastha, Shikha; Anand, Kalegowda; Asokan, Sundarrajan Pulse transit time differential measurement by Fiber Bragg Grating pulse recorder Journal Article Journal of Biomedical Optics, 20 (5), 2015. @article{Umesh2015, title = {Pulse transit time differential measurement by Fiber Bragg Grating pulse recorder}, author = {Sharath Umesh and Srivani Padme and Shikha Ambastha and Kalegowda Anand and Sundarrajan Asokan}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/057005.pdf}, doi = {10.1117/1.JBO.20.5.057005}, year = {2015}, date = {2015-05-28}, journal = {Journal of Biomedical Optics}, volume = {20}, number = {5}, abstract = {The present study reports a noninvasive technique for the measurement of the pulse transit time differential (PTTD) from the pulse pressure waveforms obtained at the carotid artery and radial artery using fiber Bragg grating pulse recorders (FBGPR). PTTD is defined as the time difference between the arrivals of a pulse pressure waveform at the carotid and radial arterial sites. The PTTD is investigated as an indicator of variation in the systolic blood pressure. The results are validated against blood pressure variation obtained from a Mindray Patient Monitor. Furthermore, the pulse wave velocity computed from the obtained PTTD is compared with the pulse wave velocity obtained from the color Doppler ultrasound system and is found to be in good agreement. The major advantage of the PTTD measurement via FBGPRs is that the data acquisition system employed can simultaneously acquire pulse pressure waveforms from both FBGPRs placed at carotid and radial arterial sites with a single time scale, which eliminates time synchronization complexity.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The present study reports a noninvasive technique for the measurement of the pulse transit time differential (PTTD) from the pulse pressure waveforms obtained at the carotid artery and radial artery using fiber Bragg grating pulse recorders (FBGPR). PTTD is defined as the time difference between the arrivals of a pulse pressure waveform at the carotid and radial arterial sites. The PTTD is investigated as an indicator of variation in the systolic blood pressure. The results are validated against blood pressure variation obtained from a Mindray Patient Monitor. Furthermore, the pulse wave velocity computed from the obtained PTTD is compared with the pulse wave velocity obtained from the color Doppler ultrasound system and is found to be in good agreement. The major advantage of the PTTD measurement via FBGPRs is that the data acquisition system employed can simultaneously acquire pulse pressure waveforms from both FBGPRs placed at carotid and radial arterial sites with a single time scale, which eliminates time synchronization complexity. |
10. | Kumar, Saurabh; Chakravarthy, Shanthanu; Ananthasuresh, G K; Amrutur, Bharadwaj; Asokan, Sundarrajan Shape estimation for flexible medical instruments: An approach based on FBG sensors embedded in a biocompatible polymer filled tube Conference Proceedings of the 2015 IEEE/RSJ IROS Workshop on Navigation and Actuation of Flexible Instruments for Medical Applications (NAFIMA), Germany, 2015. @conference{Kumar2015, title = {Shape estimation for flexible medical instruments: An approach based on FBG sensors embedded in a biocompatible polymer filled tube}, author = {Saurabh Kumar and Shanthanu Chakravarthy and G. K. Ananthasuresh and Bharadwaj Amrutur and Sundarrajan Asokan}, url = {https://www.researchgate.net/profile/Kumar_Saurabh7/publication/282572657_Shape_Estimation_for_Flexible_Medical_Instruments_-_An_Approach_Based_on_FBG_Sensors_Embedded_in_a_Biocompatible_Polymer_Filled_Tube/links/5612689d08ae6b29b49ea8cd.pdf}, year = {2015}, date = {2015-10-02}, booktitle = {Proceedings of the 2015 IEEE/RSJ IROS Workshop on Navigation and Actuation of Flexible Instruments for Medical Applications (NAFIMA), Germany}, abstract = {Real time shape estimation is important in several applications involving flexible medical instruments for minimally invasive investigations and surgery. Optical fiber sensors have been shown to be effective in this regard as compared to other methods. However, constraints arising out of bonding onto alloy substrates restrict the bending radius due to high strains and spectral distortion. Algorithms based on simple strain measurements from multiple FBG sensors to obtain exact radius of curvature impose the need for very high precision in placement. In this work, we propose a method based on Fiber Bragg Grating (FBG) sensors embedded in Polydimethylsiloxane (PDMS) placed in plastic tubing to overcome these shortcomings.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } Real time shape estimation is important in several applications involving flexible medical instruments for minimally invasive investigations and surgery. Optical fiber sensors have been shown to be effective in this regard as compared to other methods. However, constraints arising out of bonding onto alloy substrates restrict the bending radius due to high strains and spectral distortion. Algorithms based on simple strain measurements from multiple FBG sensors to obtain exact radius of curvature impose the need for very high precision in placement. In this work, we propose a method based on Fiber Bragg Grating (FBG) sensors embedded in Polydimethylsiloxane (PDMS) placed in plastic tubing to overcome these shortcomings. |
Patent Applications
Asokan, Sundarrajan; Umesh, Sharath; Raju, Sukreet; Girish, Apoorva: Apparatus and method to measure blood pressure using Fiber Bragg Grating sensor, Indian Patent Application No. 4989/CHE/2012 (06.05.16)
Vasu, Kalangi Siddeswara; Sridevi, S.; Asokan, Sundarrajan; Jayaraman, Narayanaswamy; Sood, Ajay K.: Optical biosensors having enhanced sensitivity, Indian Patent Application No. 719/CHE/2013 (14.08.15), PCT Application No. PCT/IB2014/058880
Asokan, Sundarrajan; Umesh, Sharath; Chiplunkar, Swetha: Measurement of arterial compliance using Fiber Bragg Grating pulse recorder, Indian Patent Application No. 457/CHE/2014 (07.08.15)
Vasu, Kalangi Siddeswara; Sridevi, S.; Asokan, Sundarrajan; Sood, Ajay K.: Optical sensor, methods and applications thereof, Indian Patent Application No. 6111/CHE/2014
- Formal analysis of CPS protocols and software
Principal Investigator: Aditya Kanade (Department of Computer Science and Automation)
Communication protocols and system software form critical components of cyber-physical systems. The concurrent and distributed nature of different components of a protocol make it difficult to design and debug the protocols. In addition, mechanisms for providing reliable communication over unreliable communication media (e.g. checksums,sliding window protocols) make the protocols intricate. This project aimed at formal modeling and analysis of protocols, in particular, protocols that provide reliable retransmission capabilities over noisy channels.
System software plays a significant role in cyber-physical systems by gluing together different components like sensors, controllers, actuators, and end-user devices. Control algorithms are also commonly implemented in software. The complexity of these software components make them susceptible to bugs. This project focussed at designing techniques to detect, localize, and fix bugs in programs. In particular, we explored combinations of dynamic analysis, symbolic reasoning, and machine learning to develop techniques for debugging and repair of programs.
Project Publications
1. | Thakkar, Jay; Kanade, Aditya Non-deterministic transducer models of retransmission protocols over noisy channels Journal Article Information Processing Letters, 115 (9), pp. 694-698, 2015. @article{Thakkar2015, title = {Non-deterministic transducer models of retransmission protocols over noisy channels}, author = {Jay Thakkar and Aditya Kanade}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/1-s2.0-S0020019015000691-main.pdf}, doi = {10.1016/j.ipl.2015.04.009}, year = {2015}, date = {2015-04-21}, journal = {Information Processing Letters}, volume = {115}, number = {9}, pages = {694-698}, abstract = {Retransmission protocols such as HDLC and TCP are designed to ensure reliable communication over noisy channels (i.e., channels that can corrupt messages). Thakkar et al. have recently presented an algorithmic verification technique for deterministic streaming string transducer (DSST) models of such protocols. The verification problem is posed as equivalence checking between the specification and protocol DSSTs. In this paper, we argue that more general models need to be obtained using non-deterministic streaming string transducers (NSSTs). However, equivalence checking is undecidable for NSSTs. We present two classes where the models belong to a sub-class of NSSTs for which it is decidable.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Retransmission protocols such as HDLC and TCP are designed to ensure reliable communication over noisy channels (i.e., channels that can corrupt messages). Thakkar et al. have recently presented an algorithmic verification technique for deterministic streaming string transducer (DSST) models of such protocols. The verification problem is posed as equivalence checking between the specification and protocol DSSTs. In this paper, we argue that more general models need to be obtained using non-deterministic streaming string transducers (NSSTs). However, equivalence checking is undecidable for NSSTs. We present two classes where the models belong to a sub-class of NSSTs for which it is decidable. |
2. | Santhiar, Anirudh; Pandita, Omesh; Kanade, Aditya Mining unit tests for discovery and migration of math APIs Journal Article ACM Transactions on Software Engineering and Methodology (TOSEM), pp. 4:1-33, 2014. @article{Santhiar2014, title = {Mining unit tests for discovery and migration of math APIs}, author = {Anirudh Santhiar and Omesh Pandita and Aditya Kanade}, url = {http://www.rbccps.org/wp-content/uploads/2018/12/a4-santhiar.pdf}, doi = {10.1145/2629506}, year = {2014}, date = {2014-09-30}, journal = {ACM Transactions on Software Engineering and Methodology (TOSEM)}, pages = {4:1-33}, abstract = { Today’s programming languages are supported by powerful third-party APIs. For a given application domain, it is common to have many competing APIs that provide similar functionality. Programmer productivity therefore depends heavily on the programmer’s ability to discover suitable APIs both during an initial coding phase, as well as during software maintenance. The aim of this work is to support the discovery and migration of math APIs. Math APIs are at the heart of many application domains ranging from machine learning to scientific computations. Our approach, called MathFinder, combines executable specifications of mathematical computations with unit tests (operational specifications) of API methods. Given a math expression, MathFinder synthesizes pseudo-code comprised of API methods to compute the expression by mining unit tests of the API methods. We present a sequential version of our unit test mining algorithm and also design a more scalable data-parallel version. We perform extensive evaluation of MathFinder (1) for API discovery, where math algorithms are to be implemented from scratch and (2) for API migration, where client programs utilizing a math API are to be migrated to another API. We evaluated the precision and recall of MathFinder on a diverse collection of math expressions, culled from algorithms used in a wide range of application areas such as control systems and structural dynamics. In a user study to evaluate the productivity gains obtained by using MathFinder for API discovery, the programmers who used MathFinder finished their programming tasks twice as fast as their counterparts who used the usual techniques like web and code search, IDE code completion, and manual inspection of library documentation. For the problem of API migration, as a case study, we used MathFinder to migrate Weka, a popular machine learning library. Overall, our evaluation shows that MathFinder is easy to use, provides highly precise results across several math APIs and application domains even with a small number of unit tests per method, and scales to large collections of unit tests.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Today’s programming languages are supported by powerful third-party APIs. For a given application domain, it is common to have many competing APIs that provide similar functionality. Programmer productivity therefore depends heavily on the programmer’s ability to discover suitable APIs both during an initial coding phase, as well as during software maintenance. The aim of this work is to support the discovery and migration of math APIs. Math APIs are at the heart of many application domains ranging from machine learning to scientific computations. Our approach, called MathFinder, combines executable specifications of mathematical computations with unit tests (operational specifications) of API methods. Given a math expression, MathFinder synthesizes pseudo-code comprised of API methods to compute the expression by mining unit tests of the API methods. We present a sequential version of our unit test mining algorithm and also design a more scalable data-parallel version. We perform extensive evaluation of MathFinder (1) for API discovery, where math algorithms are to be implemented from scratch and (2) for API migration, where client programs utilizing a math API are to be migrated to another API. We evaluated the precision and recall of MathFinder on a diverse collection of math expressions, culled from algorithms used in a wide range of application areas such as control systems and structural dynamics. In a user study to evaluate the productivity gains obtained by using MathFinder for API discovery, the programmers who used MathFinder finished their programming tasks twice as fast as their counterparts who used the usual techniques like web and code search, IDE code completion, and manual inspection of library documentation. For the problem of API migration, as a case study, we used MathFinder to migrate Weka, a popular machine learning library. Overall, our evaluation shows that MathFinder is easy to use, provides highly precise results across several math APIs and application domains even with a small number of unit tests per method, and scales to large collections of unit tests. |
3. | Kaleeswaran, Shalini; Tulsa, Varun; Kanade, Aditya; Orso, Alessandro MintHint: Automated synthesis of repair hints Conference Proceedings of the 36th International Conference on Software Engineering (ICSE), 31.05.-07.06.14, Hyderabad, 2014. @conference{Kaleeswaran2014, title = {MintHint: Automated synthesis of repair hints}, author = {Shalini Kaleeswaran and Varun Tulsa and Aditya Kanade and Alessandro Orso}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/p266-kaleeswaran.pdf}, doi = {10.1145/2568225.2568258}, year = {2014}, date = {2014-06-07}, booktitle = {Proceedings of the 36th International Conference on Software Engineering (ICSE), 31.05.-07.06.14, Hyderabad}, pages = {266-276}, abstract = {Being able to automatically repair programs is at the same time a very compelling vision and an extremely challenging task. In this paper, we present MintHint, a novel technique for program repair that is a departure from most of today’s approaches. Instead of trying to fully automate program repair, which is often an unachievable goal, MintHint performs statistical correlation analysis to identify expressions that are likely to occur in the repaired code and generates, using pattern-matching based synthesis, repair hints from these expressions. Intuitively, these hints suggest how to rectify a faulty statement and help developers find a complete, actual repair. We also present an empirical evaluation of MintHint in two parts. The first part is a user study that shows that, when debugging, developers’ productivity improved manyfold with the use of repair hints—instead of traditional fault localization information alone. The second part consists of applying MintHint to several faults in Unix utilities to further assess the effectiveness of the approach. Our results show that MintHint performs well even in common situations where (1) the repair space searched does not contain the exact repair, and (2) the operational specification obtained from the test cases for repair is incomplete or even imprecise, which can be challenging for approaches aiming at fully automated repair.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } Being able to automatically repair programs is at the same time a very compelling vision and an extremely challenging task. In this paper, we present MintHint, a novel technique for program repair that is a departure from most of today’s approaches. Instead of trying to fully automate program repair, which is often an unachievable goal, MintHint performs statistical correlation analysis to identify expressions that are likely to occur in the repaired code and generates, using pattern-matching based synthesis, repair hints from these expressions. Intuitively, these hints suggest how to rectify a faulty statement and help developers find a complete, actual repair. We also present an empirical evaluation of MintHint in two parts. The first part is a user study that shows that, when debugging, developers’ productivity improved manyfold with the use of repair hints—instead of traditional fault localization information alone. The second part consists of applying MintHint to several faults in Unix utilities to further assess the effectiveness of the approach. Our results show that MintHint performs well even in common situations where (1) the repair space searched does not contain the exact repair, and (2) the operational specification obtained from the test cases for repair is incomplete or even imprecise, which can be challenging for approaches aiming at fully automated repair. |
4. | Thakkar, Jay; Kanade, Aditya; Alur, Rajeev Transducer-based algorithmic verification of retransmission protocols over noisy channels Conference Proceedings of the IFIP Joint International Conference on Formal Techniques for Distributed Systems (33rd FORTE/15th FMOODS), 03.-05.06.13, Florence (Italy), 2013. @conference{Thakkar2013, title = {Transducer-based algorithmic verification of retransmission protocols over noisy channels}, author = {Jay Thakkar and Aditya Kanade and Rajeev Alur}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/10.10072F978-3-642-38592-6_15.pdf}, doi = {10.1007/978-3-642-38592-6_15}, year = {2013}, date = {2013-06-06}, booktitle = {Proceedings of the IFIP Joint International Conference on Formal Techniques for Distributed Systems (33rd FORTE/15th FMOODS), 03.-05.06.13, Florence (Italy)}, pages = {209-224}, abstract = {Unreliable communication channels are a practical reality. They add to the complexity of protocol design and verification. In this paper, we consider noisy channels which can corrupt messages. We present an approach to model and verify protocols which combine error detection and error control to provide reliable communication over noisy channels. We call these protocols retransmission protocols as they achieve reliable communication through repeated retransmissions of messages. These protocols typically use cyclic redundancy checks and sliding window protocols for error detection and control respectively. We propose models of these protocols as regular transducers operating on bit strings. Streaming string transducers provide a natural way of modeling these protocols and formalizing correctness requirements. The verification problem is posed as functional equivalence between the protocol transducer and the specification transducer. Functional equivalence checking is decidable for this class of transducers and this makes the transducer models amenable to algorithmic verification. We present case studies based on TinyOS serial communication and the HDLC retransmission protocol.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } Unreliable communication channels are a practical reality. They add to the complexity of protocol design and verification. In this paper, we consider noisy channels which can corrupt messages. We present an approach to model and verify protocols which combine error detection and error control to provide reliable communication over noisy channels. We call these protocols retransmission protocols as they achieve reliable communication through repeated retransmissions of messages. These protocols typically use cyclic redundancy checks and sliding window protocols for error detection and control respectively. We propose models of these protocols as regular transducers operating on bit strings. Streaming string transducers provide a natural way of modeling these protocols and formalizing correctness requirements. The verification problem is posed as functional equivalence between the protocol transducer and the specification transducer. Functional equivalence checking is decidable for this class of transducers and this makes the transducer models amenable to algorithmic verification. We present case studies based on TinyOS serial communication and the HDLC retransmission protocol. |
- Low-cost, optical detection of DNA for HPV detection in urine
Principal Investigator: Manoj Varma (Centre for Nano Science and Engineering)
Project Publications
1. | Kumawat, Nityanand; Pal, Parama; Varma, Manoj Quality monitoring of diesel exhaust fluid in vehicles using diffractive interference sensors Conference Proceedings of the 2014 IEEE Sensors Conference, 02.-05.11.14, Valencia (Spain), 2014. @conference{Kumawat2014, title = {Quality monitoring of diesel exhaust fluid in vehicles using diffractive interference sensors}, author = {Nityanand Kumawat and Parama Pal and Manoj Varma}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/06985343.pdf}, doi = {10.1109/ICSENS.2014.6985343}, year = {2014}, date = {2014-12-15}, booktitle = {Proceedings of the 2014 IEEE Sensors Conference, 02.-05.11.14, Valencia (Spain)}, abstract = {In this paper, we describe a simple design for an optical sensing device based on differential interferometry that can be deployed as an in-line sensor for monitoring the quality of diesel exhaust fluid inside engines of diesel vehicles. This sensor can precisely determine (to within ±1% and lower) the percentage of urea in diesel exhaust fluid (DEF), which is a critical reactant in the selective catalytic reduction (SCR) process for reducing harmful nitrous oxide emissions from diesel vehicles into the environment. The operating principle is based on diffraction of laser light from a regularly spaced microarray. Preliminary performance results indicate that our sensor can precisely determine the concentration of urea in the DEF to within ±0.0045%.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } In this paper, we describe a simple design for an optical sensing device based on differential interferometry that can be deployed as an in-line sensor for monitoring the quality of diesel exhaust fluid inside engines of diesel vehicles. This sensor can precisely determine (to within ±1% and lower) the percentage of urea in diesel exhaust fluid (DEF), which is a critical reactant in the selective catalytic reduction (SCR) process for reducing harmful nitrous oxide emissions from diesel vehicles into the environment. The operating principle is based on diffraction of laser light from a regularly spaced microarray. Preliminary performance results indicate that our sensor can precisely determine the concentration of urea in the DEF to within ±0.0045%. |
- Precision farming model for peri-urban agriculture: Technological interventions and innovations to enhance the input use efficiency
Principal Investigator: Jaywant H. Arakeri (Department of Mechanical Engineering)
The project had been collaborative effort three institutes: IISc, the University of Agricultural Sciences, Bangalore, and Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore. UAS has allotted 15 guntas of land for erecting four polyhouses and a field laboratory. An experiment was completed with baby corn (which has a growth period of two months) to optimize the growth conditions inside the polyhouse, deployment of sensors, deployment of micro irrigation/precision delivery systems for water and fertilizers. The existing technologies and their limitations could be understood through design experiments with Capsicum as test crop. The results of the experiments in the standard polyhouse gave inputs for new designs for the climatic conditions obtained in Bangalore.
Technical details on fabrication of a new type of controlled growth chamber have been discussed with engineers of a Chennai based company. Studies have been carried out to optimize the sensors to be used in the polyhouse and for plant image capture. A mini-lysimeter was developed to measure continuously transpiration rates from single plants. The mechanism of clogging of emitters/actuators was researched by examining several emitters/actuators collected from the field. An emitter test set-up to study clogging, obtain pressure-flow characteristics and develop new emitters was set up. A new type of intermittent emitter is was designed as part of an M.Des. project of the Centre for Product Design and Manufacture (CPDM).
- Remote neonatal monitoring and intervention
Principal Investigator: Bharadwaj Amrutur (Robert Bosch Centre for Cyber-Physical Systems)
A robust, easy-to-use prototype device has been developed for continuous, realtime monitoring of the core body temperatures of neonates. The design for this device has factored in considerations for ease-of-use in rural settings with minimal infrastructure. The primary utility of this wearable device is to be able to raise triggers/alarms for prompting appropriate interventions in the case of the neonate’s body temperature exceeding limits predetermined by clinicians (e.g. in the case of hypothermia or sepsis). Recent efforts have been directed into widening the sensing scope of the device by incorporating functionalities such as breathing rate determination, oxygen saturation (SpO2) detection as well as electrocardiogram (ECG) measurements.
Project Publications
1. | Joglekar, Ashish; Rawat, Alok; Rajaraman, Vasanth; Amrutur, Bharadwaj; Mony, Prem; Thankachan, Prashanth; Raj, Tony; Rao, Suman A wearable sensor for monitoring Kangaroo Mother Care for premature neonates Conference Forthcoming Proceedings of the IEEE Sensors 2018 Conference, 28.-31.10.18, New Delhi, Forthcoming. @conference{Joglekar2018, title = {A wearable sensor for monitoring Kangaroo Mother Care for premature neonates}, author = {Ashish Joglekar and Alok Rawat and Vasanth Rajaraman and Bharadwaj Amrutur and Prem Mony and Prashanth Thankachan and Tony Raj and Suman Rao}, year = {2018}, date = {2018-10-31}, booktitle = {Proceedings of the IEEE Sensors 2018 Conference, 28.-31.10.18, New Delhi}, keywords = {}, pubstate = {forthcoming}, tppubtype = {conference} } |
2. | Rao, Suman; Thankachan, Prashanth; Amrutur, Bharadwaj; Washington, Maryann; Mony, Prem Continuous, real-time monitoring of neonatal position and temperature during Kangaroo Mother Care using a wearable sensor: A techno-feasibility pilot study Journal Article Pilot and Feasibility Studies, 99 (4), pp. 1-7, 2018. @article{Rao2018, title = {Continuous, real-time monitoring of neonatal position and temperature during Kangaroo Mother Care using a wearable sensor: A techno-feasibility pilot study}, author = {Suman Rao and Prashanth Thankachan and Bharadwaj Amrutur and Maryann Washington and Prem Mony}, url = {http://www.rbccps.org/wp-content/uploads/2018/06/Rao_et_al-2018-Pilot_and_Feasibility_Studies.pdf}, doi = {10.1186/s40814-018-0293-5}, year = {2018}, date = {2018-05-21}, journal = {Pilot and Feasibility Studies}, volume = {99}, number = {4}, pages = {1-7}, abstract = {Background: Remote biomonitoring of vital parameters in hospitals and homes has the potential to improve coverage and quality of maternal and neonatal health. Wearable sensors coupled with modern information and communication technology now offer an opportunity to monitor temperatures and kangaroo mother care (KMC) adherence in a continuous and real-time manner remotely for several days’ duration in hospital and home settings. Using an innovative remote biomonitoring device to measure both temperature and baby position, we undertook a techno-feasibility study in preparation for a clinical trial. Methods: We designed and developed a wearable sensor for tracking KMC adherence and neonatal temperature, using social innovation design principles. After screening mother-infant dyads using clinical and logistic eligibility criteria, we piloted this wearable sensor along with a gateway device and the commercial cellular network. The dyads were recruited during hospitalization and followed up in the hospital and home phases for several days. Simple descriptive statistical analysis was undertaken. Results: Recruitment rate was 50% (6/12), and consenting rate was 83% (5/6) during a 2-month period. These five neonates contributed a total of 39 study days (15 hospital days and 24 home days). Their mean [± standard deviation (S.D.)] birth weight was 1490 (± 244) g. The mean (± S.D.) of the vital signs for the five babies was temperature [36.5 °C (± 0.3)], heart rate [146.5/min (± 14)], and oxygen saturation [94% (± 4)]. No severe or moderate side-effects were noted; one baby developed mild dermatitis under the device that was transient and self-limiting, yielding an incidence proportion of 20% and incidence rate of 2.6/100 person-days. None of the mothers reported any discomfort with the use of the device. Temperatures detected from 81 paired readings revealed that those from the wearable sensor were 0.2 °C lower than those detected by clinical thermometers [36.4 (± 0.7) vs 36.6 (± 0.3); < 0.001]. There was also iterative feedback that was useful for hardware and software design specifications of the wearable sensor, the gateway device, and the analytics platform. Lastly, lessons were learnt with regard to the logistics of research team interactions with healthcare professionals and study participants during the hospitalization and post-discharge home phases of the study. Conclusions: The pilot study has shown that it is feasible and acceptable to track KMC adherence as well as maternal and newborn temperatures in a potentially safe manner on a real-time mode for several days’ duration during hospitalization and home phases. The pilot has also helped inform modifications in clinical monitoring, technological modifications, and logistics planning in preparation for the definitive clinical trial.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Background: Remote biomonitoring of vital parameters in hospitals and homes has the potential to improve coverage and quality of maternal and neonatal health. Wearable sensors coupled with modern information and communication technology now offer an opportunity to monitor temperatures and kangaroo mother care (KMC) adherence in a continuous and real-time manner remotely for several days’ duration in hospital and home settings. Using an innovative remote biomonitoring device to measure both temperature and baby position, we undertook a techno-feasibility study in preparation for a clinical trial. Methods: We designed and developed a wearable sensor for tracking KMC adherence and neonatal temperature, using social innovation design principles. After screening mother-infant dyads using clinical and logistic eligibility criteria, we piloted this wearable sensor along with a gateway device and the commercial cellular network. The dyads were recruited during hospitalization and followed up in the hospital and home phases for several days. Simple descriptive statistical analysis was undertaken. Results: Recruitment rate was 50% (6/12), and consenting rate was 83% (5/6) during a 2-month period. These five neonates contributed a total of 39 study days (15 hospital days and 24 home days). Their mean [± standard deviation (S.D.)] birth weight was 1490 (± 244) g. The mean (± S.D.) of the vital signs for the five babies was temperature [36.5 °C (± 0.3)], heart rate [146.5/min (± 14)], and oxygen saturation [94% (± 4)]. No severe or moderate side-effects were noted; one baby developed mild dermatitis under the device that was transient and self-limiting, yielding an incidence proportion of 20% and incidence rate of 2.6/100 person-days. None of the mothers reported any discomfort with the use of the device. Temperatures detected from 81 paired readings revealed that those from the wearable sensor were 0.2 °C lower than those detected by clinical thermometers [36.4 (± 0.7) vs 36.6 (± 0.3); < 0.001]. There was also iterative feedback that was useful for hardware and software design specifications of the wearable sensor, the gateway device, and the analytics platform. Lastly, lessons were learnt with regard to the logistics of research team interactions with healthcare professionals and study participants during the hospitalization and post-discharge home phases of the study. Conclusions: The pilot study has shown that it is feasible and acceptable to track KMC adherence as well as maternal and newborn temperatures in a potentially safe manner on a real-time mode for several days’ duration during hospitalization and home phases. The pilot has also helped inform modifications in clinical monitoring, technological modifications, and logistics planning in preparation for the definitive clinical trial. |
3. | George, Jude Baby; Abraham, Grace; Amrutur, Bharadwaj; Sikdar, Sujit Random neuronal networks show homeostatic regulation of global activity while showing persistent changes in specific connectivity paths to theta burst stimuli Journal Article Nature Scientific Reports, 2018. @article{George2018b, title = {Random neuronal networks show homeostatic regulation of global activity while showing persistent changes in specific connectivity paths to theta burst stimuli}, author = {Jude Baby George and Grace Abraham and Bharadwaj Amrutur and Sujit Sikdar}, url = {http://www.rbccps.org/wp-content/uploads/2018/12/s41598-018-34634-x.pdf}, doi = {10.1038/s41598-018-34634-x}, year = {2018}, date = {2018-11-08}, journal = {Nature Scientific Reports}, abstract = {Learning in neuronal networks based on Hebbian principle has been shown to lead to destabilizing effects. Mechanisms have been identified that maintain homeostasis in such networks. However, the way in which these two opposing forces operate to support learning while maintaining stability is an active area of research. In this study, using neuronal networks grown on multi electrode arrays, we show that theta burst stimuli lead to persistent changes in functional connectivity along specific paths while the network maintains a global homeostasis. Simultaneous observations of spontaneous activity and stimulus evoked responses over several hours with theta burst training stimuli shows that global activity of the network quantified from spontaneous activity, which is disturbed due to theta burst stimuli is restored by homeostatic mechanisms while stimulus evoked changes in specific connectivity paths retain a memory trace of the training.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Learning in neuronal networks based on Hebbian principle has been shown to lead to destabilizing effects. Mechanisms have been identified that maintain homeostasis in such networks. However, the way in which these two opposing forces operate to support learning while maintaining stability is an active area of research. In this study, using neuronal networks grown on multi electrode arrays, we show that theta burst stimuli lead to persistent changes in functional connectivity along specific paths while the network maintains a global homeostasis. Simultaneous observations of spontaneous activity and stimulus evoked responses over several hours with theta burst training stimuli shows that global activity of the network quantified from spontaneous activity, which is disturbed due to theta burst stimuli is restored by homeostatic mechanisms while stimulus evoked changes in specific connectivity paths retain a memory trace of the training. |
4. | Mony, Prem; Thankachan, Prashanth; Bhat, Swarnarekha; Rao, Suman; Washington, Maryann; Antony, Sumi; Thomas, Annamma; Nagarajarao, Sheela C; Rao, Hiteshwar; Amrutur, Bharadwaj Remote biomonitoring of temperatures in mothers and newborns: Design, development and testing of a wearable sensor device in a tertiary-care hospital in southern India Journal Article BMJ Innovations, pp. 1-8, 2018. @article{Mony2018b, title = {Remote biomonitoring of temperatures in mothers and newborns: Design, development and testing of a wearable sensor device in a tertiary-care hospital in southern India}, author = {Prem Mony and Prashanth Thankachan and Swarnarekha Bhat and Suman Rao and Maryann Washington and Sumi Antony and Annamma Thomas and Sheela C Nagarajarao and Hiteshwar Rao and Bharadwaj Amrutur}, url = {http://www.rbccps.org/wp-content/uploads/2018/06/bmjinnov-2016-000153.full_.pdf}, doi = {10.1136/bmjinnov-2016-000153}, year = {2018}, date = {2018-02-14}, journal = {BMJ Innovations}, pages = {1-8}, abstract = {Objective: Newer technologies such as wearables, sensors, mobile telephony and computing offer opportunities to monitor vital physiological parameters and tackle healthcare problems, thereby improving access and quality of care. We describe the design, development and testing of a wearable sensor device for remote biomonitoring of body temperatures in mothers and newborns in southern India. Methods: Based on client needs and technological requirements, a wearable sensor device was designed and developed using principles of ‘social innovation’ design. The device underwent multiple iterations in product design and engineering based on user feedback, and then following preclinical testing, a techno- feasibility study and clinical trial were undertaken in a tertiary-care teaching hospital in Bangalore, India. Clinical trial phases I and IIa for evaluation of safety and efficacy were undertaken in the following sequence: 7 healthy adult volunteers; 18 healthy mothers; 3 healthy babies; 10 stable babies in the neonatal care intensive unit and 1 baby with morbidities. Time stamped skin temperature readings obtained at 5 min intervals over a 1-hour period from the device secured on upper arms of mothers and abdomen of neonates were compared against readings from thermometers used routinely in clinical practice. Results: Devices were comfortably secured on to adults and neonates, and data were efficiently transmitted via the gateway device for secure storage and retrieval for analysis. The mean skin temperatures in mothers were lower than the axillary temperatures by 2°C; and in newborns, there was a precision of –0.5°C relative to axillary measurements. While occasional minimal adverse events were noted in healthy volunteers, no adverse events were noted in mothers or neonates. Conclusions: This proof-of-concept study shows that this device is promising in terms of feasibility, safety and accuracy (with appropriate calibration) with potential for further refinements in device accuracy and pursuit of further phases of clinical research for improved maternal and neonatal health.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Objective: Newer technologies such as wearables, sensors, mobile telephony and computing offer opportunities to monitor vital physiological parameters and tackle healthcare problems, thereby improving access and quality of care. We describe the design, development and testing of a wearable sensor device for remote biomonitoring of body temperatures in mothers and newborns in southern India. Methods: Based on client needs and technological requirements, a wearable sensor device was designed and developed using principles of ‘social innovation’ design. The device underwent multiple iterations in product design and engineering based on user feedback, and then following preclinical testing, a techno- feasibility study and clinical trial were undertaken in a tertiary-care teaching hospital in Bangalore, India. Clinical trial phases I and IIa for evaluation of safety and efficacy were undertaken in the following sequence: 7 healthy adult volunteers; 18 healthy mothers; 3 healthy babies; 10 stable babies in the neonatal care intensive unit and 1 baby with morbidities. Time stamped skin temperature readings obtained at 5 min intervals over a 1-hour period from the device secured on upper arms of mothers and abdomen of neonates were compared against readings from thermometers used routinely in clinical practice. Results: Devices were comfortably secured on to adults and neonates, and data were efficiently transmitted via the gateway device for secure storage and retrieval for analysis. The mean skin temperatures in mothers were lower than the axillary temperatures by 2°C; and in newborns, there was a precision of –0.5°C relative to axillary measurements. While occasional minimal adverse events were noted in healthy volunteers, no adverse events were noted in mothers or neonates. Conclusions: This proof-of-concept study shows that this device is promising in terms of feasibility, safety and accuracy (with appropriate calibration) with potential for further refinements in device accuracy and pursuit of further phases of clinical research for improved maternal and neonatal health. |
5. | Gubbi, Sagar Venkatesh; Rao, Hiteshwar; Amrutur, Bharadwaj Continuous ambulatory electrocardiography Technical Report Robert Bosch Centre for Cyber-Physical Systems 3rd Floor, SID Building, Entrepreneurship Centre, Indian Institute of Science, Bangalore – 560012, (RBCCPS/TR/0002), 2016. @techreport{Gubbi2016, title = {Continuous ambulatory electrocardiography}, author = {Sagar Venkatesh Gubbi and Hiteshwar Rao and Bharadwaj Amrutur}, url = {https://github.com/s-gv/rnicu/blob/master/ecg/report/ecg_tech_report.pdf}, year = {2016}, date = {2016-02-29}, number = {RBCCPS/TR/0002}, address = {3rd Floor, SID Building, Entrepreneurship Centre, Indian Institute of Science, Bangalore – 560012}, institution = {Robert Bosch Centre for Cyber-Physical Systems}, abstract = {Continous ambulatory recording of the electrocardiogram could help in early detection of cardiovascular diseases, which could lower healthcare costs and improve prognosis. For such continuous recordings, sensors that are discreet and have few electrodes are needed. Two electrode ECG systems exhibit worse power line interference than three electrode systems, but are desirable because they have one less electrode. A circuit model that captures power line interference is reviewed, which is then used to analyse the performance characteristics of different interface circuits. For two electrode systems, an adaptive filter is found to be effective in digitally removing any remnant power line interference. Finally, our analysis shows that the low-impedance electrode in a three electrode system may be sized differently than the high impedance electrodes while keeping the power line interference sufficiently small. This observation leads to a pseudo two electrode electrocardiograph which is in fact a three electrode system with an inconspicuous third electrode.}, keywords = {}, pubstate = {published}, tppubtype = {techreport} } Continous ambulatory recording of the electrocardiogram could help in early detection of cardiovascular diseases, which could lower healthcare costs and improve prognosis. For such continuous recordings, sensors that are discreet and have few electrodes are needed. Two electrode ECG systems exhibit worse power line interference than three electrode systems, but are desirable because they have one less electrode. A circuit model that captures power line interference is reviewed, which is then used to analyse the performance characteristics of different interface circuits. For two electrode systems, an adaptive filter is found to be effective in digitally removing any remnant power line interference. Finally, our analysis shows that the low-impedance electrode in a three electrode system may be sized differently than the high impedance electrodes while keeping the power line interference sufficiently small. This observation leads to a pseudo two electrode electrocardiograph which is in fact a three electrode system with an inconspicuous third electrode. |
6. | Rao, Hiteshwar; Saxena, Dhruv; Kumar, Saurabh; Gubbi, Sagar Venkatesh; Amrutur, Bharadwaj; Mony, Prem; Thankachan, Prashanth; Shankar, Kiruba; Rao, Suman; Bhat, Swarnarekha Design of a wearable remote neonatal health monitoring device Conference Proceedings of the 7th International Joint Conference on Biomedical Engineering Systems and Technologies (BIOSTEC), 03.-06.03.14, Angers (France), 2016. @conference{Rao2016, title = {Design of a wearable remote neonatal health monitoring device}, author = {Hiteshwar Rao and Dhruv Saxena and Saurabh Kumar and Sagar Venkatesh Gubbi and Bharadwaj Amrutur and Prem Mony and Prashanth Thankachan and Kiruba Shankar and Suman Rao and Swarnarekha Bhat}, doi = {10.1007/978-3-319-26129-4_3}, year = {2016}, date = {2016-01-07}, booktitle = {Proceedings of the 7th International Joint Conference on Biomedical Engineering Systems and Technologies (BIOSTEC), 03.-06.03.14, Angers (France)}, pages = {34-51}, abstract = {In this text we present the design of a wearable health monitoring device capable of remotely monitoring health parameters of neonates for the first few weeks after birth. The device is primarily aimed at continuously tracking the skin temperature to indicate the onset of hypothermia in newborns. A medical grade thermistor is responsible for temperature measurement and is directly interfaced to a microcontroller with an integrated bluetooth low energy radio. An inertial sensor is also present in the device to facilitate breathing rate measurement which has been discussed briefly. Sensed data is transferred securely over bluetooth low energy radio to a nearby gateway, which relays the information to a central database for real time monitoring. Low power optimizations at both the circuit and software levels ensure a prolonged battery life. The device is packaged in a baby friendly, water proof housing and is easily sterilizable and reusable.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } In this text we present the design of a wearable health monitoring device capable of remotely monitoring health parameters of neonates for the first few weeks after birth. The device is primarily aimed at continuously tracking the skin temperature to indicate the onset of hypothermia in newborns. A medical grade thermistor is responsible for temperature measurement and is directly interfaced to a microcontroller with an integrated bluetooth low energy radio. An inertial sensor is also present in the device to facilitate breathing rate measurement which has been discussed briefly. Sensed data is transferred securely over bluetooth low energy radio to a nearby gateway, which relays the information to a central database for real time monitoring. Low power optimizations at both the circuit and software levels ensure a prolonged battery life. The device is packaged in a baby friendly, water proof housing and is easily sterilizable and reusable. |
7. | Gubbi, Sagar Venkatesh; Amrutur, Bharadwaj Adaptive pulse width control and sampling for pulse oximetry Journal Article IEEE Transactions on Biomedical Circuits and Systems, 9 (2), pp. 272-283, 2015. @article{Gubbi2015, title = {Adaptive pulse width control and sampling for pulse oximetry}, author = {Sagar Venkatesh Gubbi and Bharadwaj Amrutur}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/06846367.pdf}, doi = {10.1109/TBCAS.2014.2326712}, year = {2015}, date = {2015-04-30}, journal = {IEEE Transactions on Biomedical Circuits and Systems}, volume = {9}, number = {2}, pages = {272-283}, abstract = {Remote sensing of physiological parameters could be a cost effective approach to improving health care, and low-power sensors are essential for remote sensing because these sensors are often energy constrained. This paper presents a power optimized photoplethysmographic sensor interface to sense arterial oxygen saturation, a technique to dynamically trade off SNR for power during sensor operation, and a simple algorithm to choose when to acquire samples in photoplethysmography. A prototype of the proposed pulse oximeter built using commercial-off-the-shelf (COTS) components is tested on 10 adults. The dynamic adaptation techniques described reduce power consumption considerably compared to our reference implementation, and our approach is competitive to state-of-the-art implementations. The techniques presented in this paper may be applied to low-power sensor interface designs where acquiring samples is expensive in terms of power as epitomized by pulse oximetry.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Remote sensing of physiological parameters could be a cost effective approach to improving health care, and low-power sensors are essential for remote sensing because these sensors are often energy constrained. This paper presents a power optimized photoplethysmographic sensor interface to sense arterial oxygen saturation, a technique to dynamically trade off SNR for power during sensor operation, and a simple algorithm to choose when to acquire samples in photoplethysmography. A prototype of the proposed pulse oximeter built using commercial-off-the-shelf (COTS) components is tested on 10 adults. The dynamic adaptation techniques described reduce power consumption considerably compared to our reference implementation, and our approach is competitive to state-of-the-art implementations. The techniques presented in this paper may be applied to low-power sensor interface designs where acquiring samples is expensive in terms of power as epitomized by pulse oximetry. |
8. | Prabhakar, T V; Mysore, Ujwal; Saini, Uday; Vinoy, K J; Amrutur, Bharadwaj NFC for pervasive healthcare monitoring Conference Proceedings of the 28th International Conference on VLSI Design and the 14th International Conference on Embedded Systems, 03.-07.01.15, Bangalore, 2015. @conference{Prabhakar2015, title = {NFC for pervasive healthcare monitoring}, author = {T. V. Prabhakar and Ujwal Mysore and Uday Saini and K. J. Vinoy and Bharadwaj Amrutur}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/07031711.pdf}, doi = {10.1109/VLSID.2015.18}, year = {2015}, date = {2015-02-05}, booktitle = {Proceedings of the 28th International Conference on VLSI Design and the 14th International Conference on Embedded Systems, 03.-07.01.15, Bangalore}, pages = {75-80}, abstract = {We undertake a step-by-step approach in the design of two Near Field Communication (NFC) products for pervasive healthcare monitoring. Our first product is an NFC based battery charger circuit to charge a thermometer equipped with wireless communication. Our system design has a simple linear charger, with overvoltage and under voltage protection implemented as an android App. The NFC power source provides 13 — 15 mW of continuous power and is able to charge a 45mAH battery in about 10 hours from deep discharge to full charge state. Since the weight of the charger is about 3 grams and the size is about 2 cms in diameter, this product is useful for wearable sensor devices and provides a convenient way of recharging the batteries without the need for any connectors in the device. This allows devices to be hermetically sealed, besides enabling smaller form factors. The second product is an NFC based battery-less medical grade thermometer. To obtain the temperature of a single patient, a maximum of 10 seconds is sufficient to read the sensor value starting from placement of a smartphone over the product.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } We undertake a step-by-step approach in the design of two Near Field Communication (NFC) products for pervasive healthcare monitoring. Our first product is an NFC based battery charger circuit to charge a thermometer equipped with wireless communication. Our system design has a simple linear charger, with overvoltage and under voltage protection implemented as an android App. The NFC power source provides 13 — 15 mW of continuous power and is able to charge a 45mAH battery in about 10 hours from deep discharge to full charge state. Since the weight of the charger is about 3 grams and the size is about 2 cms in diameter, this product is useful for wearable sensor devices and provides a convenient way of recharging the batteries without the need for any connectors in the device. This allows devices to be hermetically sealed, besides enabling smaller form factors. The second product is an NFC based battery-less medical grade thermometer. To obtain the temperature of a single patient, a maximum of 10 seconds is sufficient to read the sensor value starting from placement of a smartphone over the product. |
9. | Jeyashankar, Karthik Ramkumar; Mahalley, Makrand; Amrutur, Bharadwaj A time-based low voltage body temperature monitoring unit Conference Proceedings of the 27th International Conference on VLSI Design and the 13th International Conference on Embedded Systems, 05.-09.01.14, Mumbai, 2014. @conference{Jeyashankar2014, title = {A time-based low voltage body temperature monitoring unit}, author = {Karthik Ramkumar Jeyashankar and Makrand Mahalley and Bharadwaj Amrutur}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/06733186.pdf}, doi = {10.1109/VLSID.2014.97}, year = {2014}, date = {2014-02-06}, booktitle = {Proceedings of the 27th International Conference on VLSI Design and the 13th International Conference on Embedded Systems, 05.-09.01.14, Mumbai}, pages = {522-527}, abstract = {A neonatal temperature monitoring system operating in sub threshold regime that utilizes time mode signal processing is presented. Resistance deviations in a thermistor due to temperature variations are converted to delay variations that are subsequently quantized by a Delay measurement unit (DMU). The DMU does away with the need for any analog circuitry and is synthesizable entirely from digital logic. An FPGA implementation of the system demonstrates the viability of employing time mode signal processing, and measured results show that temperature resolution better than 0.1°C can be achieved using this approach.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } A neonatal temperature monitoring system operating in sub threshold regime that utilizes time mode signal processing is presented. Resistance deviations in a thermistor due to temperature variations are converted to delay variations that are subsequently quantized by a Delay measurement unit (DMU). The DMU does away with the need for any analog circuitry and is synthesizable entirely from digital logic. An FPGA implementation of the system demonstrates the viability of employing time mode signal processing, and measured results show that temperature resolution better than 0.1°C can be achieved using this approach. |
10. | Kumar, Saurabh; Rao, Hiteshwar; Amrutur, Bharadwaj; Asokan, Sundarrajan Continuous core body temperature estimation via surface temperature measurements using wearable sensors – Is it feasible? Conference Proceedings of the 7th International Conference on Biomedical Electronics and Devices, 03.-06.03.14, Angers (France), 2014. @conference{Kumar2014, title = {Continuous core body temperature estimation via surface temperature measurements using wearable sensors – Is it feasible?}, author = {Saurabh Kumar and Hiteshwar Rao and Bharadwaj Amrutur and Sundarrajan Asokan}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/BIODEVICES_2014_42.pdf}, doi = {10.5220/0004889901810186}, year = {2014}, date = {2014-03-06}, booktitle = {Proceedings of the 7th International Conference on Biomedical Electronics and Devices, 03.-06.03.14, Angers (France)}, pages = {181-186}, abstract = {Core body temperature is an important indicator of well being of humans. The commonly used methods and sites of measurement do not lend well for continuous measurement at home. However, continuous monitoring using non-invasive, small, low cost sensors could have many applications like detection of hypothermia and fever in low birth weight neonates in rural settings. We investigate the feasibility of making such measurements using only skin temperature sensors. Our initial sensor prototype is composed of flexible materials, with embedded high precision thermistors and is based on dual heat flux technique. Our initial experiments show that the reliable estimation of core temperature under varying ambient conditions and at different measurement sites is a challenge, but promising. Further work is needed to combine results from experimental measurements and theoretical simulations to provide good insights and enable accurate estimation of core body temperature for long term monitoring at home.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } Core body temperature is an important indicator of well being of humans. The commonly used methods and sites of measurement do not lend well for continuous measurement at home. However, continuous monitoring using non-invasive, small, low cost sensors could have many applications like detection of hypothermia and fever in low birth weight neonates in rural settings. We investigate the feasibility of making such measurements using only skin temperature sensors. Our initial sensor prototype is composed of flexible materials, with embedded high precision thermistors and is based on dual heat flux technique. Our initial experiments show that the reliable estimation of core temperature under varying ambient conditions and at different measurement sites is a challenge, but promising. Further work is needed to combine results from experimental measurements and theoretical simulations to provide good insights and enable accurate estimation of core body temperature for long term monitoring at home. |
11. | Rao, Hiteshwar; Saxena, Dhruv; Kumar, Saurabh; Gubbi, Sagar Venkatesh; Amrutur, Bharadwaj; Mony, Prem; Thankachan, Prasanth; Shankar, Kiruba; Rao, Suman; Bhat, Swarnarekha Low power remote neonatal temperature monitoring device Conference Proceedings of the 7th International Conference on Biomedical Electronics and Devices, 03.-06.03.14, Angers (France), 2014. @conference{Rao2014, title = {Low power remote neonatal temperature monitoring device}, author = {Hiteshwar Rao and Dhruv Saxena and Saurabh Kumar and Sagar Venkatesh Gubbi and Bharadwaj Amrutur and Prem Mony and Prasanth Thankachan and Kiruba Shankar and Suman Rao and Swarnarekha Bhat}, url = {https://pdfs.semanticscholar.org/45e5/9d035f47c2fba8f9dec597db1f56cf4e083c.pdf}, doi = {10.5220/0004798300280038}, year = {2014}, date = {2014-03-06}, booktitle = {Proceedings of the 7th International Conference on Biomedical Electronics and Devices, 03.-06.03.14, Angers (France)}, pages = {28-38}, abstract = {In this paper we present the design of a wearable temperature sensing device for remote neonatal monitoring. It is designed for continuous and real-time monitoring of the infants in remote rural areas, for the first few weeks after their birth. It is capable of sensing the neonate’s skin temperature with 0.1°C accuracy to detect the early onset of hypothermia. The sensed data is transferred securely over bluetooth low energy radio to a nearby gateway, which then relays the information to a central database for real time monitoring. The device incorporates a medical grade thermistor which is directly interfaced to a microcontroller with an integrated bluetooth low energy radio. Low power optimizations at both the circuit and software levels ensure sleep currents of only 1uA, ensuring very long battery life. The device is packaged in a baby friendly, water proof housing and is easily sterilizable and reusable.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } In this paper we present the design of a wearable temperature sensing device for remote neonatal monitoring. It is designed for continuous and real-time monitoring of the infants in remote rural areas, for the first few weeks after their birth. It is capable of sensing the neonate’s skin temperature with 0.1°C accuracy to detect the early onset of hypothermia. The sensed data is transferred securely over bluetooth low energy radio to a nearby gateway, which then relays the information to a central database for real time monitoring. The device incorporates a medical grade thermistor which is directly interfaced to a microcontroller with an integrated bluetooth low energy radio. Low power optimizations at both the circuit and software levels ensure sleep currents of only 1uA, ensuring very long battery life. The device is packaged in a baby friendly, water proof housing and is easily sterilizable and reusable. |
12. | Alex, Doney; Gorur, Pushkar; Amrutur, Bharadwaj; Ramakrishnan, Kalpathi LampTop: Touch detection for a projector-camera system based on shape classification Conference Proceedings of the 2013 ACM International conference on Interactive Tabletops and Surfaces (ITS), 06.-09.10.13, St. Andrews (UK), 2013. @conference{Alex2013, title = {LampTop: Touch detection for a projector-camera system based on shape classification}, author = {Doney Alex and Pushkar Gorur and Bharadwaj Amrutur and Kalpathi Ramakrishnan}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/p429-alex.pdf}, doi = {10.1145/2512349.2514921}, year = {2013}, date = {2013-10-09}, booktitle = {Proceedings of the 2013 ACM International conference on Interactive Tabletops and Surfaces (ITS), 06.-09.10.13, St. Andrews (UK)}, pages = {429-432}, abstract = {The LampTop enables an effective low cost touch interface utilizing only a single camera and a pico projector. It embeds a small shape in the image generated by the user application (e.g. a touch screen menu with icons) and detects touch by measuring the geometrical distortion in the camera captured image. Fourier shape descriptors are extracted from the camera-captured image to obtain an estimate of the shape distortion. The touch event is detected using a Support Vector Machine. Quantitative results show that the proposed method can effectively detect touch.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } The LampTop enables an effective low cost touch interface utilizing only a single camera and a pico projector. It embeds a small shape in the image generated by the user application (e.g. a touch screen menu with icons) and detects touch by measuring the geometrical distortion in the camera captured image. Fourier shape descriptors are extracted from the camera-captured image to obtain an estimate of the shape distortion. The touch event is detected using a Support Vector Machine. Quantitative results show that the proposed method can effectively detect touch. |
Patent Applications
Gubbi, Sagar Venkatesh; Amrutur, Bharadwaj: Low power pulse oximeter and a method thereof, Indian Patent Application No. 1979/CHE/2014 (01.01.16)
Amrutur, Bharadwaj; Rao, Hiteshwar; Saxena, Dhruv; Mony, Prem: A method and a device for monitoring physiological characteristics with adaptive power management, Indian Patent Application No. 4499/CHE/2014 (01.07.16)
- Sensor system for monitoring stroke patients in rehabilitation
Principal Investigator: K. Gopinath (Department of Computer Science and Automation)
The project’s original aim was to enable stroke patients in their rehabilitation by providing an interesting way to perform the required exercises. A stroke patient, during his/her rehabilitation period is required to perform regular, repetitive exercises, especially some predefined movements of the affected region, to gain back the functionality of those regions. However, these exercises are often highly repetitive in nature and may become boring over the time, because of which the patient may stop doing it. Instead, the basic idea was to make such movements part of some video game(s) that would have the desired motions (exercise movements). We also planned to capture the movement of the patient during these exercises by placing sensors on the moving body parts and provide feedback to the patient or the doctor, either off-line or, if possible, on-line regarding the patient performance.
In the process of formally defining the problem, we spoke to medical specialists who work in related areas. During these discussions it became clear that the Human Gait Analysis is a far more pressing problem. Given its immediate need, the cost of doing so can be reduced substantially. Also, from the point of validation, there are well defined standards available for Gait Analysis, like Optical Gait Analysis, which can be used for evaluating any new system.
Given the commonality of the hardware for our original problem and Human Gait Analysis and due to lack of data for the original problem, we therefore decided to shift our attention to Human Gait Analysis. Based on our discussions with specialists, our new goals was to calculate the clinically important joint angles (knee joint angle, ankle joint angle, hip joint angle, etc.) using IMU Sensors (Inertial Measurement Unit) and to validate the results using an Optical system (BIMRA Gait Lab). If the angles produced by the IMU sensors is comparable with that produced by Optical system, then potentially, one can use IMU sensors system to do Gait Analysis at a much lower cost.
Project Publications
1. | Kumar, Sandeep; Gopinath, K; Rocchi, Laura; Sukumar, Poorna Talked; Kulkarni, Suyameendra; Sampath, Jayanth Towards a portable human gait analysis and monitoring system Conference Proceedings of the 2018 International Conference on Signals and Systems (ICSigSys), 01.-03.05.18, Bali (Indonesia), 2018. @conference{Kumar2018bb, title = {Towards a portable human gait analysis and monitoring system}, author = {Sandeep Kumar and K. Gopinath and Laura Rocchi and Poorna Talked Sukumar and Suyameendra Kulkarni and Jayanth Sampath}, url = {http://www.rbccps.org/wp-content/uploads/2018/12/08372660.pdf}, doi = {10.1109/ICSIGSYS.2018.8372660}, year = {2018}, date = {2018-06-07}, booktitle = {Proceedings of the 2018 International Conference on Signals and Systems (ICSigSys), 01.-03.05.18, Bali (Indonesia)}, abstract = {Human Gait analysis is useful in many cases, such as, detecting the underlying cause of an abnormal gait, rehabilitation of subjects suffering from motor related diseases such as Parkinson’s disease or Cerebral Palsy, improving the athletic performance of sports person etc. However, gait analysis has seen limited usage, especially in developing countries, because of the high cost involved in setting up a gait laboratory. We present a portable gait analysis system using Inertial Measurement Unit (IMU) sensors to collect movement data and a Smart-phone to process it. IMU sensors has gained significant popularity in the last few years as viable option for gait analysis because its low cost, small size and ease of use. Using the accelerometer and gyroscope data from 3 EXL-S3 IMU sensors (on thigh, shank and foot), we measure kinematic angles in the sagittal plane and detect Heel Strike (HT) and Toe Off (TO) events using methods based on [11] and [4] respectively. To measure the accuracy of our system, we compare it with an Optical Gait Analysis system, which is the current gold standard for gait analysis 1 . We measure the gait parameters for 3 healthy individuals belonging to different age group and achieve an RMSE of 4.739° ± 1.961°, 3.7° ± 3.02° and 4.12° ± 1.21° for Knee Flexion Extension, Ankle Dorsi Flexion respectively and Hip Flexion Extension respectively. We measure the Heel Strike and Toe Off using shank and foot mounted sensor independently. 34.5 ± 28.3 ms and 27.5 ± 32.8 ms is the RMSE for HT calculated by shank and foot sensor w.r.t. optical system respectively. The RMSE for Toe Off is 36.2 ± 36.8 ms and 37.5 ± 35.9 ms for shank and foot sensor w.r.t. optical system respectively.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } Human Gait analysis is useful in many cases, such as, detecting the underlying cause of an abnormal gait, rehabilitation of subjects suffering from motor related diseases such as Parkinson’s disease or Cerebral Palsy, improving the athletic performance of sports person etc. However, gait analysis has seen limited usage, especially in developing countries, because of the high cost involved in setting up a gait laboratory. We present a portable gait analysis system using Inertial Measurement Unit (IMU) sensors to collect movement data and a Smart-phone to process it. IMU sensors has gained significant popularity in the last few years as viable option for gait analysis because its low cost, small size and ease of use. Using the accelerometer and gyroscope data from 3 EXL-S3 IMU sensors (on thigh, shank and foot), we measure kinematic angles in the sagittal plane and detect Heel Strike (HT) and Toe Off (TO) events using methods based on [11] and [4] respectively. To measure the accuracy of our system, we compare it with an Optical Gait Analysis system, which is the current gold standard for gait analysis 1 . We measure the gait parameters for 3 healthy individuals belonging to different age group and achieve an RMSE of 4.739° ± 1.961°, 3.7° ± 3.02° and 4.12° ± 1.21° for Knee Flexion Extension, Ankle Dorsi Flexion respectively and Hip Flexion Extension respectively. We measure the Heel Strike and Toe Off using shank and foot mounted sensor independently. 34.5 ± 28.3 ms and 27.5 ± 32.8 ms is the RMSE for HT calculated by shank and foot sensor w.r.t. optical system respectively. The RMSE for Toe Off is 36.2 ± 36.8 ms and 37.5 ± 35.9 ms for shank and foot sensor w.r.t. optical system respectively. |
2. | Rangaprakash, D; Dutt, Narayana D Study of wrist pulse signals using time domain spatial features Journal Article Computers and Electrical Engineering, 45 , pp. 100-107, 2015. @article{Rangaprakash2015, title = {Study of wrist pulse signals using time domain spatial features}, author = {D. Rangaprakash and D. Narayana Dutt}, url = {http://www.rbccps.org/wp-content/uploads/2018/12/1-s2.0-S0045790615000051-main.pdf}, doi = {10.1016/j.compeleceng.2014.12.016}, year = {2015}, date = {2015-07-31}, journal = {Computers and Electrical Engineering}, volume = {45}, pages = {100-107}, abstract = {Blood travels throughout the body and thus its flow is modulated by changes in body condition. As a consequence, the wrist pulse signal contains important information about the status of the human body. In this work we have employed signal processing techniques to extract important information from these signals. Radial artery pulse pressure signals are acquired at wrist position noninvasively for several subjects for two cases of interest, viz. before and after exercise, and before and after lunch. Further analysis is performed by fitting a bi-modal Gaussian model to the data and extracting spatial features from the fit. The spatial features show statistically significant (p < 0.001) changes between the groups for both the cases, which indicates that they are effective in distinguishing the changes taking place due to exercise or food intake. Recursive cluster elimination based support vector machine classifier is used to classify between the groups. A high classification accuracy of 99.71% is achieved for the exercise case and 99.94% is achieved for the lunch case. This paper demonstrates the utility of certain spatial features in studying wrist pulse signals obtained under various experimental conditions. The ability of the spatial features in distinguishing changing body conditions can be potentially used for various healthcare applications.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Blood travels throughout the body and thus its flow is modulated by changes in body condition. As a consequence, the wrist pulse signal contains important information about the status of the human body. In this work we have employed signal processing techniques to extract important information from these signals. Radial artery pulse pressure signals are acquired at wrist position noninvasively for several subjects for two cases of interest, viz. before and after exercise, and before and after lunch. Further analysis is performed by fitting a bi-modal Gaussian model to the data and extracting spatial features from the fit. The spatial features show statistically significant (p < 0.001) changes between the groups for both the cases, which indicates that they are effective in distinguishing the changes taking place due to exercise or food intake. Recursive cluster elimination based support vector machine classifier is used to classify between the groups. A high classification accuracy of 99.71% is achieved for the exercise case and 99.94% is achieved for the lunch case. This paper demonstrates the utility of certain spatial features in studying wrist pulse signals obtained under various experimental conditions. The ability of the spatial features in distinguishing changing body conditions can be potentially used for various healthcare applications. |
3. | Rangaprakash, D; Dutt, Narayana D Analysis of wrist pulse signals using spatial features in time domain Conference Proceedings of the 2014 International Conference on Communication and Signal Processing, 03.-05.04.14, Melmaruvathur, 2014. @conference{Rangaprakash2014, title = {Analysis of wrist pulse signals using spatial features in time domain}, author = {D. Rangaprakash and D. Narayana Dutt}, url = {http://www.rbccps.org/wp-content/uploads/2018/12/06949859.pdf}, doi = {10.1109/ICCSP.2014.6949859}, year = {2014}, date = {2014-11-10}, booktitle = {Proceedings of the 2014 International Conference on Communication and Signal Processing, 03.-05.04.14, Melmaruvathur}, abstract = {Wrist pulse signal contains more important information about the health status of a person and pulse signal diagnosis has been employed in oriental medicine since very long time. In this paper we have used signal processing techniques to extract information from wrist pulse signals. For this purpose we have acquired radial artery pulse signals at wrist position noninvasively for different cases of interest. The wrist pulse waveforms have been analyzed using spatial features. Results have been obtained for the case of wrist pulse signals recorded for several subjects before exercise and after exercise. It is shown that the spatial features show statistically significant changes for the two cases and hence they are effective in distinguishing the changes taking place due to exercise. Support vector machine classifier is used to classify between the groups, and a high classification accuracy of 99.71% is achieved. Thus this paper demonstrates the utility of the spatial features in studying wrist pulse signals obtained under various recording conditions. The ability of the model to distinguish changes occurring under two different recording conditions can be potentially used for healthcare applications.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } Wrist pulse signal contains more important information about the health status of a person and pulse signal diagnosis has been employed in oriental medicine since very long time. In this paper we have used signal processing techniques to extract information from wrist pulse signals. For this purpose we have acquired radial artery pulse signals at wrist position noninvasively for different cases of interest. The wrist pulse waveforms have been analyzed using spatial features. Results have been obtained for the case of wrist pulse signals recorded for several subjects before exercise and after exercise. It is shown that the spatial features show statistically significant changes for the two cases and hence they are effective in distinguishing the changes taking place due to exercise. Support vector machine classifier is used to classify between the groups, and a high classification accuracy of 99.71% is achieved. Thus this paper demonstrates the utility of the spatial features in studying wrist pulse signals obtained under various recording conditions. The ability of the model to distinguish changes occurring under two different recording conditions can be potentially used for healthcare applications. |
4. | Sukumar, Poorna Talked; Gopinath, K Human activity recognition by matching curve shapes Conference Proceedings of the 21st International Conference of Neural Information Processing (ICONIP), 03.-06.11.14, Kuching (Malaysia), Lecture Notes in Computer Science 2014. @conference{Sukumar2014, title = {Human activity recognition by matching curve shapes}, author = {Poorna Talked Sukumar and K. Gopinath}, doi = {10.1007/978-3-319-12640-1_43}, year = {2014}, date = {2014-11-06}, booktitle = {Proceedings of the 21st International Conference of Neural Information Processing (ICONIP), 03.-06.11.14, Kuching (Malaysia)}, pages = {352-360}, series = {Lecture Notes in Computer Science}, abstract = {In this paper, we present a new method for Human Activity Recognition (HAR) from body-worn accelerometers or inertial sensors using comparison of curve shapes. Simple motion activities have characteristic patterns that are visible in the time series representations of the sensor data. These time series representations, such as the 3D accelerations or the Euler angles (roll, pitch and yaw), can be treated as curves and activities can be recognized by matching patterns (shapes) in the curves using curve comparison and alignment techniques. We transform the sensor signals into cubic B-splines and parametrize the curves with respect to arc length for comparison. We tested our algorithm on the accelerometer data collected at Cleveland State University. The 3D acceleration signals were segmented at high-level and subject-dependent ‘representative’ curves for the activities were constructed with which test curves were compared and labeled with an overall accuracy rate of 88.46% by our algorithm.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } In this paper, we present a new method for Human Activity Recognition (HAR) from body-worn accelerometers or inertial sensors using comparison of curve shapes. Simple motion activities have characteristic patterns that are visible in the time series representations of the sensor data. These time series representations, such as the 3D accelerations or the Euler angles (roll, pitch and yaw), can be treated as curves and activities can be recognized by matching patterns (shapes) in the curves using curve comparison and alignment techniques. We transform the sensor signals into cubic B-splines and parametrize the curves with respect to arc length for comparison. We tested our algorithm on the accelerometer data collected at Cleveland State University. The 3D acceleration signals were segmented at high-level and subject-dependent ‘representative’ curves for the activities were constructed with which test curves were compared and labeled with an overall accuracy rate of 88.46% by our algorithm. |
5. | Rangaprakash, D Statistical analysis of wrist pulse signals obtained under different food intake conditions Conference Proceedings of the 2014 International Conference on Communication and Signal Processing, 03.-05.04.14, Melmaruvathur, 2014. @conference{Rangaprakash2014c, title = {Statistical analysis of wrist pulse signals obtained under different food intake conditions}, author = {D. Rangaprakash}, url = {http://www.rbccps.org/wp-content/uploads/2018/12/06950081.pdf}, doi = {10.1109/ICCSP.2014.6950081}, year = {2014}, date = {2014-11-10}, booktitle = {Proceedings of the 2014 International Conference on Communication and Signal Processing, 03.-05.04.14, Melmaruvathur}, abstract = {It is well known that wrist pulse signals contain information about the status of health of a person and hence diagnosis based on pulse signals has assumed great importance since long time. In this paper the efficacy of signal processing techniques in extracting useful information from wrist pulse signals has been demonstrated by using signals recorded under two different experimental conditions viz. before lunch condition and after lunch condition. We have used Pearson’s product-moment correlation coefficient, which is an effective measure of phase synchronization, in making a statistical analysis of wrist pulse signals. Contour plots and boxplots are used to illustrate various differences. Two-sample t-tests show that the correlations show statistically significant differences between the groups. Results show that the correlation coefficient is effective in distinguishing the changes taking place after having lunch. This paper demonstrates the ability of the wrist pulse signals in detecting changes occurring under two different conditions. The study assumes importance in view of limited literature available on the analysis of wrist pulse signals in the case of food intake and also in view of its potential health care applications.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } It is well known that wrist pulse signals contain information about the status of health of a person and hence diagnosis based on pulse signals has assumed great importance since long time. In this paper the efficacy of signal processing techniques in extracting useful information from wrist pulse signals has been demonstrated by using signals recorded under two different experimental conditions viz. before lunch condition and after lunch condition. We have used Pearson’s product-moment correlation coefficient, which is an effective measure of phase synchronization, in making a statistical analysis of wrist pulse signals. Contour plots and boxplots are used to illustrate various differences. Two-sample t-tests show that the correlations show statistically significant differences between the groups. Results show that the correlation coefficient is effective in distinguishing the changes taking place after having lunch. This paper demonstrates the ability of the wrist pulse signals in detecting changes occurring under two different conditions. The study assumes importance in view of limited literature available on the analysis of wrist pulse signals in the case of food intake and also in view of its potential health care applications. |
6. | Rangaprakash, D; Dutt, Narayana D Study of wrist pulse signals using a bi-modal Gaussian model Conference Proceedings of the 2014 International Conference on Advances in Computing, Communications and Informatics (ICACCI), 24.-27.09.14, New Delhi, 2014. @conference{Rangaprakash2014b, title = {Study of wrist pulse signals using a bi-modal Gaussian model}, author = {D. Rangaprakash and D. Narayana Dutt}, url = {http://www.rbccps.org/wp-content/uploads/2018/12/06968397.pdf}, doi = {10.1109/ICACCI.2014.6968397}, year = {2014}, date = {2014-12-01}, booktitle = {Proceedings of the 2014 International Conference on Advances in Computing, Communications and Informatics (ICACCI), 24.-27.09.14, New Delhi}, abstract = {Wrist pulse signals contain important information about the health of a person and hence diagnosis based on pulse signals has assumed great importance. In this paper we demonstrate the efficacy of a two term Gaussian model to extract information from pulse signals. Results have been obtained by conducting experiments on several subjects to record wrist pulse signals for the cases of before exercise and after exercise. Parameters have been extracted from the recorded signals using the model and a paired t-test is performed, which shows that the parameters are significantly different between the two groups. Further, a recursive cluster elimination based support vector machine is used to perform classification between the groups. An average classification accuracy of 99.46% is obtained, along with top classifiers. It is thus shown that the parameters of the Gaussian model show changes across groups and hence the model is effective in distinguishing the changes taking place due to the two different recording conditions. The study has potential applications in healthcare.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } Wrist pulse signals contain important information about the health of a person and hence diagnosis based on pulse signals has assumed great importance. In this paper we demonstrate the efficacy of a two term Gaussian model to extract information from pulse signals. Results have been obtained by conducting experiments on several subjects to record wrist pulse signals for the cases of before exercise and after exercise. Parameters have been extracted from the recorded signals using the model and a paired t-test is performed, which shows that the parameters are significantly different between the two groups. Further, a recursive cluster elimination based support vector machine is used to perform classification between the groups. An average classification accuracy of 99.46% is obtained, along with top classifiers. It is thus shown that the parameters of the Gaussian model show changes across groups and hence the model is effective in distinguishing the changes taking place due to the two different recording conditions. The study has potential applications in healthcare. |
- Simulation environment with active feedback for epidural procedures
Principal Investigator: M. S. Bobji (Department of Mechanical Engineering)
Epidural procedures are routinely performed by trained physicians for anesthesia and treatment. It is a procedure that requires considerable skill on the part of the physician to correctly place the needle and catheter at the exact position in the epidural space as puncturing or damaging the dura mater may lead to side effects like headache or even paralysis. Training on cadavers is one way to provide necessary skills in the procedure. The current project involved the development of a training system to realistically provide a simulation environment with a haptic feedback and immersive visualisation. Some key features of the project are development of custom sensors and mechanisms and an intelligent software engine to provide measurements, feedback and operations of the training environment.
Project Publications
1. | Shrikanth, V; Simha, K R Y; Bobji, Musuvathi S Frictional force measurement during stick-slip motion of a piezoelectric walker Journal Article Proceedings of the 2015 IEEE International Conference on Industrial Technology (ICIT), 17.-19.03.15, Seville (Spain), (1463-1468), 2015. @article{Shrikanth2015, title = {Frictional force measurement during stick-slip motion of a piezoelectric walker}, author = {V. Shrikanth and K. R. Y. Simha and Musuvathi S. Bobji}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/07125303.pdf}, doi = {10.1109/ICIT.2015.7125303}, year = {2015}, date = {2015-06-18}, journal = {Proceedings of the 2015 IEEE International Conference on Industrial Technology (ICIT), 17.-19.03.15, Seville (Spain)}, number = {1463-1468}, abstract = {The stick-slip actuator motion is dependent on its natural frequency. The backward motion of the actuator during the slip phase due to the stiffness alters the motion of any stickslip friction principle based positioners drastically. This work is an attempt to design and fabricate a simple and compact piezoelectric walker integrated with a force sensor to measure the frictional force during the slip phase. The underlying idea is to achieve a smooth motion of the walker by understanding the dynamics during slipping.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The stick-slip actuator motion is dependent on its natural frequency. The backward motion of the actuator during the slip phase due to the stiffness alters the motion of any stickslip friction principle based positioners drastically. This work is an attempt to design and fabricate a simple and compact piezoelectric walker integrated with a force sensor to measure the frictional force during the slip phase. The underlying idea is to achieve a smooth motion of the walker by understanding the dynamics during slipping. |
2. | Shrikanth, V; Bobji, Musuvathi S A non-resonant mass sensor to eliminate the “missing mass” effect during mass measurement of biological materials Journal Article Review of Scientific Instruments, pp. 105006:1-9, 2014. @article{Shrikanth2014, title = {A non-resonant mass sensor to eliminate the “missing mass” effect during mass measurement of biological materials }, author = {V. Shrikanth and Musuvathi S. Bobji}, url = {http://www.rbccps.org/wp-content/uploads/2018/12/1.4899201.pdf}, doi = {10.1063/1.4899201}, year = {2014}, date = {2014-10-24}, journal = {Review of Scientific Instruments}, pages = {105006:1-9}, abstract = {Resonant sensors and crystal oscillators for mass detection need to be excited at very high natural frequencies (MHz). Use of such systems to measure mass of biological materials affects the accuracy of mass measurement due to their viscous and/or viscoelastic properties. The measurement limitation of such sensor system is the difficulty in accounting for the “missing mass” of the biological specimen in question. A sensor system has been developed in this work, to be operated in the stiffness controlled region at very low frequencies as compared to its fundamental natural frequency. The resulting reduction in the sensitivity due to non-resonant mode of operation of this sensor is compensated by the high resolution of the sensor. The mass of different aged Drosophila Melanogaster (fruit fly) is measured. The difference in its mass measurement during resonant mode of operation is also presented. That, viscosity effects do not affect the working of this non-resonant mass sensor is clearly established by direct comparison.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Resonant sensors and crystal oscillators for mass detection need to be excited at very high natural frequencies (MHz). Use of such systems to measure mass of biological materials affects the accuracy of mass measurement due to their viscous and/or viscoelastic properties. The measurement limitation of such sensor system is the difficulty in accounting for the “missing mass” of the biological specimen in question. A sensor system has been developed in this work, to be operated in the stiffness controlled region at very low frequencies as compared to its fundamental natural frequency. The resulting reduction in the sensitivity due to non-resonant mode of operation of this sensor is compensated by the high resolution of the sensor. The mass of different aged Drosophila Melanogaster (fruit fly) is measured. The difference in its mass measurement during resonant mode of operation is also presented. That, viscosity effects do not affect the working of this non-resonant mass sensor is clearly established by direct comparison. |
- Smart transportation and mobility solutions
Principal Investigator: T. G. Sitharam (Department of Civil Engineering)
Integrated Urban Transportation Planning includes collaborative planning of land use and transport, integration of various modes of transport in terms of infrastructure like coexisting terminals for public transportation and service like having common fare payment systems etc.
Intelligent Transport System (ITS) is another promising and prevalent means of improving mobility in an optimal manner, ITS provides very efficient and smooth coordination among functioning of various infrastructure elements that constitutes the transport system. It is majorly divided into Advanced Traffic Management System (ATMS), Advanced Traveler Management System (ATIS), and Advanced Public Transport Systems (APTS). All three of these involve utilization of telematics. Real time estimation of traffic stream characteristics such as traffic flow, speed and traffic density act as inputs to all three and helps in unparalleled enhancement of mobility.
Project Publications
1. | Prabuchandran, K J; Bhatnagar, Shalabh; Borkar, Vivek S An actor-critic algorithm based on Grassmanian search Conference Proceedings of the 53rd IEEE Annual Conference on Decision and Control (CDC), 15.-17.12.14, Los Angeles (USA), 2015. @conference{Prabuchandran2015b, title = {An actor-critic algorithm based on Grassmanian search}, author = {K. J. Prabuchandran and Shalabh Bhatnagar and Vivek S. Borkar}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/07039948.pdf}, doi = {10.1109/CDC.2014.7039948}, year = {2015}, date = {2015-02-12}, booktitle = {Proceedings of the 53rd IEEE Annual Conference on Decision and Control (CDC), 15.-17.12.14, Los Angeles (USA)}, pages = {3597-3602}, abstract = {We propose the first online actor-critic scheme with adaptive basis to find a local optimal control policy for a Markov Decision Process (MDP) under the weighted discounted cost objective. We parameterize both the policy in the actor and the value function in the critic. The actor performs gradient search in the space of policy parameters using simultaneous perturbation stochastic approximation (SPSA) gradient estimates. This gradient computation requires estimates of value function that are provided by the critic by minimizing a mean square Bellman error objective. In order to obtain good estimates of the value function, the critic adaptively tunes the basis functions (or the features) to obtain the best representation of the value function using gradient search in the Grassmanian of features. Our control algorithm makes use of multi-timescale stochastic approximation. The actor updates its parameters along the slowest time scale. The critic uses two time scales to estimate the value function. For any given feature value, our algorithm performs gradient search in the parameter space via a residual gradient scheme on the faster timescale and, on a medium timescale, performs gradient search in the Grassman manifold of features. We provide an outline of the proof of convergence of our control algorithm to a locally optimum policy. We show empirical results using our algorithm as well as a similar algorithm that uses temporal difference (TD) learning in place of the residual gradient scheme for the faster timescale updates.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } We propose the first online actor-critic scheme with adaptive basis to find a local optimal control policy for a Markov Decision Process (MDP) under the weighted discounted cost objective. We parameterize both the policy in the actor and the value function in the critic. The actor performs gradient search in the space of policy parameters using simultaneous perturbation stochastic approximation (SPSA) gradient estimates. This gradient computation requires estimates of value function that are provided by the critic by minimizing a mean square Bellman error objective. In order to obtain good estimates of the value function, the critic adaptively tunes the basis functions (or the features) to obtain the best representation of the value function using gradient search in the Grassmanian of features. Our control algorithm makes use of multi-timescale stochastic approximation. The actor updates its parameters along the slowest time scale. The critic uses two time scales to estimate the value function. For any given feature value, our algorithm performs gradient search in the parameter space via a residual gradient scheme on the faster timescale and, on a medium timescale, performs gradient search in the Grassman manifold of features. We provide an outline of the proof of convergence of our control algorithm to a locally optimum policy. We show empirical results using our algorithm as well as a similar algorithm that uses temporal difference (TD) learning in place of the residual gradient scheme for the faster timescale updates. |
2. | Prabuchandran, K J; Kumar, Hemanth A N; Bhatnagar, Shalabh Multi-agent reinforcement learning for traffic signal control Conference Proceedings of the 17th IEEE International Conference on Intelligent Transportation Systems (ITSC), China, 2014. @conference{Prabuchandran2014, title = {Multi-agent reinforcement learning for traffic signal control}, author = {K. J. Prabuchandran and A. N. Hemanth Kumar and Shalabh Bhatnagar}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/06958095.pdf}, doi = {10.1109/ITSC.2014.6958095}, year = {2014}, date = {2014-10-11}, booktitle = {Proceedings of the 17th IEEE International Conference on Intelligent Transportation Systems (ITSC), China}, pages = {2529-2534}, abstract = {Optimal control of traffic lights at junctions or traffic signal control (TSC) is essential for reducing the average delay experienced by the road users amidst the rapid increase in the usage of vehicles. In this paper, we formulate the TSC problem as a discounted cost Markov decision process (MDP) and apply multi-agent reinforcement learning (MARL) algorithms to obtain dynamic TSC policies. We model each traffic signal junction as an independent agent. An agent decides the signal duration of its phases in a round-robin (RR) manner using multi-agent Q-learning with either ε-greedy or UCB based exploration strategies. It updates its Q-factors based on the cost feedback signal received from its neighbouring agents. This feedback signal can be easily constructed and is shown to be effective in minimizing the average delay of the vehicles in the network. We show through simulations over VISSIM that our algorithms perform significantly better than both the standard fixed signal timing (FST) algorithm and the saturation balancing (SAT) algorithm over two real road networks.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } Optimal control of traffic lights at junctions or traffic signal control (TSC) is essential for reducing the average delay experienced by the road users amidst the rapid increase in the usage of vehicles. In this paper, we formulate the TSC problem as a discounted cost Markov decision process (MDP) and apply multi-agent reinforcement learning (MARL) algorithms to obtain dynamic TSC policies. We model each traffic signal junction as an independent agent. An agent decides the signal duration of its phases in a round-robin (RR) manner using multi-agent Q-learning with either ε-greedy or UCB based exploration strategies. It updates its Q-factors based on the cost feedback signal received from its neighbouring agents. This feedback signal can be easily constructed and is shown to be effective in minimizing the average delay of the vehicles in the network. We show through simulations over VISSIM that our algorithms perform significantly better than both the standard fixed signal timing (FST) algorithm and the saturation balancing (SAT) algorithm over two real road networks. |
- SPMU based solar water pump and smart controller
Principal Investigator: L. Umanand (Department of Electronic Systems Engineering)
Solar pump units provide varying power to pumps with varying solar isolation. The solar panels are also by about 25% oversized to accommodate wide seasonal variations. As a result, the pump rarely runs at full capacity, and thereby, subjects the pump, the pump motor and motor driver to run at lower efficiencies most of the time.
We developed a new solar pump system with an intelligent solar power management unit (SPMU) to help regulate constant power to the pump. The unit diverts solar power to battery whenever it is greater than the pump power requirement, and also supplements the solar power with battery power whenever it is lesser than the pump power requirement. The unit features “maximum power point tracking (MPPT)” to harness maximum power from the solar panel. The system also (uniquely) provides the capability to measure the total and time profile of water pumped, and also supports the collection of inline Total Dissolved Solids (TDS), a critical water quality parameter that is necessary to determine appropriate watering levels.
Patent Application
Warrior, Jay; Sekhar, Muddu; Misra, Prasant: Smart solar water pump system, Indian Patent Application No. 3578/CHE/2014
- Studies into impact of dust and PV temperature on PV system (performance) efficiency in tropical regions
Principal Investigator: Monto Mani (Centre for Sustainable Technologies and Centre for Product Design and Manufacturing)
Clean energy technologies are an imminent necessity to sustain modern civilization and ensuring environmental vitality for future generations. While solar photovoltaics (PV) for clean electricity generation is promising, ensuring its optimum performance is crucial for sustainability. Often, onsite parameters such as dust-settlement and ambient climatic factors have a significant bearing on PV system output, including the dependence on clean-water for maintenance. Despite enormous ongoing efforts to devise novel materials for higher PV yield and efficiency, there is inadequate study dealing with onsite factors. Dust deposition and operating PV temperatures are acute considerations in tropical regions such as India. Research and development, under the current project, investigated the impact of dust settlement, associated water-based cleaning cycles and operating PV temperature profiles on PV system output (efficiency) for various PV material and design configurations. Further, to minimize use of clean water for maintenance, given site-specific conditions, an effort was made to evolve a methodology to identify appropriate cleaning mechanisms. Further, results of the study paved way for research in other domains of material sciences such as development of dust repelling coatings and self-cleaning glasses.
Project Publications
1. | Mani, Monto; Aaditya, Gayathri; Balaji, N C Appreciating performance of a BIPV lab in Bangalore (India) Proceeding 2016. @proceedings{Mani2016, title = {Appreciating performance of a BIPV lab in Bangalore (India)}, author = {Monto Mani and Gayathri Aaditya and N. C. Balaji}, year = {2016}, date = {2016-06-24}, booktitle = {Proceedings of the 32nd European Photovoltaic Solar Energy Conference and Exhibition (EU PVSEC 2016), Munich (Germany)}, abstract = {A BIPV (Building Integrated Photovoltaic) is essentially PV integrated as a building envelope (roof, wall, façade, and fenestration) regulating indoor thermal comfort and generating on-site energy. Tropical regions are solar rich (>4 kWH/m2/day) and generally warmer (20~30°C) and impose a specific need for preventing indoor heat build-up and increased natural ventilation. Roofs have been found to be the single largest contributor of indoor heat gain, and with PV integration this gain is amplified due to low thermal mass and higher radiation. This results in a stratified temperature gradient between the (PV) roof and the floor below in conjunction with a higher natural buoyancy of warm air below the PV panel. In tropical conditions, PV performance is characterized by higher a higher operating temperature that is generally detrimental to its efficiency and aggravates indoor heat buildup when integrated as the roof. The interplay between indoor thermal comfort and PV performance needs to be carefully investigated particularly the influence of stratified indoor temperature on thermal comfort and the natural buoyancy induced ventilation on PV performance. The current study is an experimental investigation into a 5.25 kWp roof integrated BIPV lab located at the campus of the Indian Institute of Science, Bangalore (India).}, keywords = {}, pubstate = {published}, tppubtype = {proceedings} } A BIPV (Building Integrated Photovoltaic) is essentially PV integrated as a building envelope (roof, wall, façade, and fenestration) regulating indoor thermal comfort and generating on-site energy. Tropical regions are solar rich (>4 kWH/m2/day) and generally warmer (20~30°C) and impose a specific need for preventing indoor heat build-up and increased natural ventilation. Roofs have been found to be the single largest contributor of indoor heat gain, and with PV integration this gain is amplified due to low thermal mass and higher radiation. This results in a stratified temperature gradient between the (PV) roof and the floor below in conjunction with a higher natural buoyancy of warm air below the PV panel. In tropical conditions, PV performance is characterized by higher a higher operating temperature that is generally detrimental to its efficiency and aggravates indoor heat buildup when integrated as the roof. The interplay between indoor thermal comfort and PV performance needs to be carefully investigated particularly the influence of stratified indoor temperature on thermal comfort and the natural buoyancy induced ventilation on PV performance. The current study is an experimental investigation into a 5.25 kWp roof integrated BIPV lab located at the campus of the Indian Institute of Science, Bangalore (India). |
2. | Pillai, Rohitkumar; Aaditya, Gayathri; Mani, Monto; Ramamurthy, Praveen Cell (module) temperature regulated performance of a building integrated photovoltaic system in tropical conditions Journal Article Renewable Energy, 72 , pp. 140-148, 2016. @article{Pillai2016, title = {Cell (module) temperature regulated performance of a building integrated photovoltaic system in tropical conditions}, author = {Rohitkumar Pillai and Gayathri Aaditya and Monto Mani and Praveen Ramamurthy}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/1-s2.0-S0960148114003632-main.pdf}, doi = {10.1016/j.renene.2014.06.023}, year = {2016}, date = {2016-12-30}, journal = {Renewable Energy}, volume = {72}, pages = {140-148}, abstract = {The performance of a building integrated photovoltaic system (BIPV) has to be commendable, not only on the electrical front but also on the thermal comfort front, thereby fulfilling the true responsibility of an energy providing shelter. Given the low thermal mass of BIPV systems, unintended and undesired outcomes of harnessing solar energy − such as heat gain into the building, especially in tropical regions − have to be adequately addressed. Cell (module) temperature is one critical factor that affects both the electrical and the thermal performance of such installations. The current paper discusses the impact of cell (module) temperature on both the electrical efficiency and thermal comfort by investigating the holistic performance of one such system (5.25 kWp) installed at the Centre for Sustainable Technologies in the Indian Institute of Science, Bangalore. Some recommendations (passive techniques) for improving the performance and making BIPV structures thermally comfortable have been listed out.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The performance of a building integrated photovoltaic system (BIPV) has to be commendable, not only on the electrical front but also on the thermal comfort front, thereby fulfilling the true responsibility of an energy providing shelter. Given the low thermal mass of BIPV systems, unintended and undesired outcomes of harnessing solar energy − such as heat gain into the building, especially in tropical regions − have to be adequately addressed. Cell (module) temperature is one critical factor that affects both the electrical and the thermal performance of such installations. The current paper discusses the impact of cell (module) temperature on both the electrical efficiency and thermal comfort by investigating the holistic performance of one such system (5.25 kWp) installed at the Centre for Sustainable Technologies in the Indian Institute of Science, Bangalore. Some recommendations (passive techniques) for improving the performance and making BIPV structures thermally comfortable have been listed out. |
3. | Khanum, Khadija K; Rao, Abhishek; Balaji, N C; Mani, Monto; Ramamurthy, Praveen Performance evaluation for PV systems to synergistic influences of dust, wind and panel temperatures: Spectral insight Conference Proceedings of the 43rd IEEE Photovoltaic Specialists Conference (PVSC 2016), Portland (USA), 2016. @conference{Khanum2016b, title = {Performance evaluation for PV systems to synergistic influences of dust, wind and panel temperatures: Spectral insight}, author = {Khadija K. Khanum and Abhishek Rao and N. C. Balaji and Monto Mani and Praveen Ramamurthy}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/07749917.pdf}, doi = {10.1109/PVSC.2016.7749917}, year = {2016}, date = {2016-11-21}, booktitle = {Proceedings of the 43rd IEEE Photovoltaic Specialists Conference (PVSC 2016), Portland (USA)}, abstract = {Dust is a ubiquitous occurrence influencing PV performance, primarily by cutting the solar radiation reaching the PV cell. Since the PV cell is always encapsulated, the dynamics of light reaching the cell involves a complex interplay of scattering, absorption and reflection of light starting from surface of glass till it reaches the cell. Dust settling on the glass adds to this complex interplay and alters the way both direct and diffused radiation reaches the PV cell. The impact of dust thus far has always been understood to be detrimental, which may not be valid under all conditions. Dust on PV (panel) glass could be studied as optical filters determining which wavelength of light reaches the PV cell. While few studies on dust have dealt with the spectral-band of light necessary for PV output, they have overlooked the fact that the remainder of the spectra is absorbed by the PV system, and could influence its output. It is possible that dust actually absorbs the unwanted IR that would otherwise increase cell temperature, degrading its output. Preliminary study concurs that certain kind of dust deposition at specific settlement densities could be beneficial for PV performance by absorbing unwanted IR. The current study deals with Si based PV which is known to predominantly operate on the visible part of the solar spectrum, and is easily affected by temperature (IR absorption) and dust.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } Dust is a ubiquitous occurrence influencing PV performance, primarily by cutting the solar radiation reaching the PV cell. Since the PV cell is always encapsulated, the dynamics of light reaching the cell involves a complex interplay of scattering, absorption and reflection of light starting from surface of glass till it reaches the cell. Dust settling on the glass adds to this complex interplay and alters the way both direct and diffused radiation reaches the PV cell. The impact of dust thus far has always been understood to be detrimental, which may not be valid under all conditions. Dust on PV (panel) glass could be studied as optical filters determining which wavelength of light reaches the PV cell. While few studies on dust have dealt with the spectral-band of light necessary for PV output, they have overlooked the fact that the remainder of the spectra is absorbed by the PV system, and could influence its output. It is possible that dust actually absorbs the unwanted IR that would otherwise increase cell temperature, degrading its output. Preliminary study concurs that certain kind of dust deposition at specific settlement densities could be beneficial for PV performance by absorbing unwanted IR. The current study deals with Si based PV which is known to predominantly operate on the visible part of the solar spectrum, and is easily affected by temperature (IR absorption) and dust. |
4. | Khanum, Khadija K; Mani, Monto; Ramamurthy, Praveen Spectral studies investigating the influence of dust on solar transmittance Presentation 24.06.2016. @misc{Khanum2016, title = {Spectral studies investigating the influence of dust on solar transmittance}, author = {Khadija K. Khanum and Monto Mani and Praveen Ramamurthy}, year = {2016}, date = {2016-06-24}, booktitle = {Proceedings of the 32nd European Photovoltaic Solar Energy Conference and Exhibition (EU PVSEC 2016), Munich (Germany)}, pages = {2049-2051}, abstract = {Photovoltaic (PV) performance is significantly impacted due to dust settlement on the glass covering the panel, fundamentally understood as transmittance loss. Maintaining a dust free PV panel requires a minimum of 0.5 L/m2 of water daily in most tropical conditions where dust settlement is common. Most commercially available cells are Si based which harnesses as electricity most of the visible part of the solar spectrum, while the rest of the spectrum is absorbed as heat. However given the fact that the cross-section of a typical solar panel is multi-layered, with the top being a hi-transmittance glass, it is crucial to understand influence of dust on this primary layer. Dust though universally present is not universally uniform and varies depending on the atmospheric pollution, terrain (natural and anthropogenic) aggravations and vegetation. The composition is thus extremely varied. Little is understood on the geometry of settled dust, its composition and spectral absorptivity in response to incident direct and diffused radiation and its angle of incidence. The current study experimentally investigates the spectral response (Spectroradiometer) of dust characteristic to Bangalore for varying densities from mild soiling (~1g/m2) to heavy soiling (>5g/m2) and its elemental composition. The spectral absorptivity has also been compared for near direct solar incidence vs diffused. Elemental composition (EDAX) of the dust samples partially explained their spectral absorptivity. The results of the study provides critical insight into possible benefit of dust, at specific densities and compositions, in reducing the heat gain of solar cell by absorbing IR at the surface of the glass.}, keywords = {}, pubstate = {published}, tppubtype = {presentation} } Photovoltaic (PV) performance is significantly impacted due to dust settlement on the glass covering the panel, fundamentally understood as transmittance loss. Maintaining a dust free PV panel requires a minimum of 0.5 L/m2 of water daily in most tropical conditions where dust settlement is common. Most commercially available cells are Si based which harnesses as electricity most of the visible part of the solar spectrum, while the rest of the spectrum is absorbed as heat. However given the fact that the cross-section of a typical solar panel is multi-layered, with the top being a hi-transmittance glass, it is crucial to understand influence of dust on this primary layer. Dust though universally present is not universally uniform and varies depending on the atmospheric pollution, terrain (natural and anthropogenic) aggravations and vegetation. The composition is thus extremely varied. Little is understood on the geometry of settled dust, its composition and spectral absorptivity in response to incident direct and diffused radiation and its angle of incidence. The current study experimentally investigates the spectral response (Spectroradiometer) of dust characteristic to Bangalore for varying densities from mild soiling (~1g/m2) to heavy soiling (>5g/m2) and its elemental composition. The spectral absorptivity has also been compared for near direct solar incidence vs diffused. Elemental composition (EDAX) of the dust samples partially explained their spectral absorptivity. The results of the study provides critical insight into possible benefit of dust, at specific densities and compositions, in reducing the heat gain of solar cell by absorbing IR at the surface of the glass. |
5. | Khadija, Khadija K; Shruti, Soni; Ramamurthy, Praveen; Mani, Monto Evaluating effectiveness of non-water based cleaning mechanisms for PV systems Conference Proceedings of the 3rd South African Solar Energy Conference (SASEC2015), 2015. @conference{Khadija2015, title = {Evaluating effectiveness of non-water based cleaning mechanisms for PV systems}, author = {Khadija K. Khadija and Soni Shruti and Praveen Ramamurthy and Monto Mani}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/Khanum_Evaluating_2015.pdf}, year = {2015}, date = {2015-05-13}, booktitle = {Proceedings of the 3rd South African Solar Energy Conference (SASEC2015)}, pages = {29-32}, abstract = {PV systems in tropical regions are gifted with ample sunshine, but also vulnerabilities to high cell temperatures and dust settlement. Dust related degradation is progressive and if left unattended, can severely inhibit by more than 40% the efficiency and output of the system. Current mechanisms of cleaning PV systems adopt large quantities of clean water, making the system unsustainable. The current study thereby investigates the effectiveness of non-water based cleaning mechanisms based on traditional palm-leaf brooms. These brooms were found to be more than 90% effective in comparison to water based cleaning. The reason for this effective cleaning has been further scrutinized based on micro-structure studies and dust adhering properties.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } PV systems in tropical regions are gifted with ample sunshine, but also vulnerabilities to high cell temperatures and dust settlement. Dust related degradation is progressive and if left unattended, can severely inhibit by more than 40% the efficiency and output of the system. Current mechanisms of cleaning PV systems adopt large quantities of clean water, making the system unsustainable. The current study thereby investigates the effectiveness of non-water based cleaning mechanisms based on traditional palm-leaf brooms. These brooms were found to be more than 90% effective in comparison to water based cleaning. The reason for this effective cleaning has been further scrutinized based on micro-structure studies and dust adhering properties. |
6. | Rao, Abhishek; Pillai, Rohitkumar; Mani, Monto; Ramamurthy, Praveen Influence of dust deposition on photovoltaic panel performance Conference Proceedings of the 4th International Conference on Advances in Energy Research (ICAER), 10.-12.12.13, Mumbai, 2014. @conference{Rao2014b, title = {Influence of dust deposition on photovoltaic panel performance}, author = {Abhishek Rao and Rohitkumar Pillai and Monto Mani and Praveen Ramamurthy}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/1-s2.0-S1876610214011874-main.pdf}, doi = {10.1016/j.egypro.2014.07.310}, year = {2014}, date = {2014-08-25}, booktitle = {Proceedings of the 4th International Conference on Advances in Energy Research (ICAER), 10.-12.12.13, Mumbai}, pages = {690-700}, abstract = {Solar photovoltaic power plants are ideally located in regions with high insolation levels. Photovoltaic performance is affected by high cell temperatures, soiling, mismatch and other balance-of-systems related losses. It is crucial to understand the significance of each of these losses on system performance. Soiling, highly dependent on installation conditions, is a complex performance issue to accurately quantify. The settlement of dust on panel surfaces may or may not be uniform depending on local terrain and environmental factors such as ambient temperature, wind and rainfall. It is essential to investigate the influence of dust settlement on the operating characteristics of photovoltaic systems to better understand losses in performance attributable to soiling. The current–voltage (I–V) characteristics of photovoltaic panels reveal extensive information to support degradation analysis of the panels. This paper attempts to understand performance losses due to dust through a dynamic study into the I–V characteristics of panels under varying soiling conditions in an outdoor experimental test-bed. Further, the results of an indoor study simulating the performance of photovoltaic panels under different dust deposition regimes are discussed in this paper.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } Solar photovoltaic power plants are ideally located in regions with high insolation levels. Photovoltaic performance is affected by high cell temperatures, soiling, mismatch and other balance-of-systems related losses. It is crucial to understand the significance of each of these losses on system performance. Soiling, highly dependent on installation conditions, is a complex performance issue to accurately quantify. The settlement of dust on panel surfaces may or may not be uniform depending on local terrain and environmental factors such as ambient temperature, wind and rainfall. It is essential to investigate the influence of dust settlement on the operating characteristics of photovoltaic systems to better understand losses in performance attributable to soiling. The current–voltage (I–V) characteristics of photovoltaic panels reveal extensive information to support degradation analysis of the panels. This paper attempts to understand performance losses due to dust through a dynamic study into the I–V characteristics of panels under varying soiling conditions in an outdoor experimental test-bed. Further, the results of an indoor study simulating the performance of photovoltaic panels under different dust deposition regimes are discussed in this paper. |
7. | Rao, Abhishek; Pillai, Rohitkumar; Mani, Monto; Ramamurthy, Praveen An experimental investigation into the interplay of wind, dust and temperature on photovoltaic performance in tropical conditions Presentation 29.08.2013. @misc{Rao2013b, title = {An experimental investigation into the interplay of wind, dust and temperature on photovoltaic performance in tropical conditions}, author = {Abhishek Rao and Rohitkumar Pillai and Monto Mani and Praveen Ramamurthy}, year = {2013}, date = {2013-08-29}, booktitle = {Proceedings of the 12th International Conference on Sustainable Energy Technologies (SET) 26.-29.08.13, Hongkong (China)}, keywords = {}, pubstate = {published}, tppubtype = {presentation} } |
8. | Pillai, Rohitkumar; Rao, Abhishek; Mani, Monto; Ramamurthy, Praveen Understanding near sunrise and sunset PV system behaviour to identify measures to maximize effective energy yield Presentation 29.08.2013. @misc{Pillai2013, title = {Understanding near sunrise and sunset PV system behaviour to identify measures to maximize effective energy yield}, author = {Rohitkumar Pillai and Abhishek Rao and Monto Mani and Praveen Ramamurthy}, year = {2013}, date = {2013-08-29}, booktitle = {Proceedings of the 12th International Conference on Sustainable Energy Technologies (SET), China}, keywords = {}, pubstate = {published}, tppubtype = {presentation} } |
- Verified model of real–time operating systems for multi-core processors
Principal Investigator: Deepak D’Souza (Department of Computer Science and Automation)
Real-time operating systems (RTOS) play a central role in embedded system applications, and will likely do so for cyber-physical systems in the future. Given the paradigm shift towards multi-core processors, most embedded processors are likely to be multi-core ones in the near future. Today’s RTOS that are typically designed to be run on uni-processors will need to be re-designed and implemented for multi-core processors. Reasoning about the correctness of embedded applications is impossible without a precise specification and proof of correctness of the RTOS itself.
In this project we used the open source Free-RTOS operating system as an example. To begin with we defined a precise specification (for example in a formal modelling language like Z notation or Event B) of the intended behaviour of a Free-RTOS-like OS on a multicore processor. Secondly, we proposed a multicore implementation of Free-RTOS. Finally we investigated techniques to prove the correctness of this implementation with respect to the top-level specification.
Project Publications
1. | Divakaran, Sumesh; D’Souza, Deepak; Kushwah, Anirudh; Sampath, Prahladavaradan; Sridhar, Nigamanth; Woodcock, Jim Refinement-based verification of the FreeRTOS scheduler in VCC Conference Proceedings of the 17th International Conference on Formal Engineering Methods (ICFEM), France, Lecture Notes in Computer Science 2015. @conference{Divakaran2015, title = {Refinement-based verification of the FreeRTOS scheduler in VCC}, author = {Sumesh Divakaran and Deepak D’Souza and Anirudh Kushwah and Prahladavaradan Sampath and Nigamanth Sridhar and Jim Woodcock}, doi = {10.1007/978-3-319-25423-4_11}, year = {2015}, date = {2015-11-05}, booktitle = {Proceedings of the 17th International Conference on Formal Engineering Methods (ICFEM), France}, pages = {170-186}, series = {Lecture Notes in Computer Science}, abstract = {We describe our experience with verifying the scheduler-related functionality of FreeRTOS, a popular open-source embedded real-time operating system. We propose a methodology for carrying out refinement-based proofs of functional correctness of abstract data types in the popular code-level verifier VCC. We then apply this methodology to carry out a full machine-checked proof of the functional correctness of the FreeRTOS scheduler. We describe the bugs found during this exercise, the fixes made, and the effort involved.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } We describe our experience with verifying the scheduler-related functionality of FreeRTOS, a popular open-source embedded real-time operating system. We propose a methodology for carrying out refinement-based proofs of functional correctness of abstract data types in the popular code-level verifier VCC. We then apply this methodology to carry out a full machine-checked proof of the functional correctness of the FreeRTOS scheduler. We describe the bugs found during this exercise, the fixes made, and the effort involved. |
2. | Chandrasekaran, Prakash; Kumar, Shibu K B; Minz, Remish L; D’Souza, Deepak; Meshram, Lomesh A multi-core version of FreeRTOS verified for datarace and deadlock freedom Conference Proceedings of the 12th ACM/IEEE International Conference on Formal Methods and Models for Codesign (MEMOCODE), 19.-21.10.14, Lausanne (Switzerland), 2014. @conference{Chandrasekaran2014, title = {A multi-core version of FreeRTOS verified for datarace and deadlock freedom}, author = {Prakash Chandrasekaran and K. B. Shibu Kumar and Remish L. Minz and Deepak D’Souza and Lomesh Meshram}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/06961844.pdf}, doi = {10.1109/MEMCOD.2014.6961844}, year = {2014}, date = {2014-11-20}, booktitle = {Proceedings of the 12th ACM/IEEE International Conference on Formal Methods and Models for Codesign (MEMOCODE), 19.-21.10.14, Lausanne (Switzerland)}, pages = {62-71}, abstract = {We present the design of a multicore version of FreeRTOS, a popular open source real-time operating system for embedded applications. We generalize the scheduling policy of FreeRTOS to schedule the n highest-priority longest-waiting tasks, for an n-core processsor. We use a locking mechanism that provides maximum decoupling between tasks, while ensuring mutually exclusive access to kernel data-structures. We provide an implementation of the portable part of FreeRTOS (written in C) and provide the device specific implementation of the locking mechanism for Intel and ARM Cortex multicore processors. We model the locking mechanism and the locking protocol used by the API’s in the Spin model-checking tool and verify that the design is free from dataraces and deadlocks. Finally, we extend the existing FreeRTOS Windows simulator to simulate our multicore version of FreeRTOS, and evaluate its performance on some demo applications.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } We present the design of a multicore version of FreeRTOS, a popular open source real-time operating system for embedded applications. We generalize the scheduling policy of FreeRTOS to schedule the n highest-priority longest-waiting tasks, for an n-core processsor. We use a locking mechanism that provides maximum decoupling between tasks, while ensuring mutually exclusive access to kernel data-structures. We provide an implementation of the portable part of FreeRTOS (written in C) and provide the device specific implementation of the locking mechanism for Intel and ARM Cortex multicore processors. We model the locking mechanism and the locking protocol used by the API’s in the Spin model-checking tool and verify that the design is free from dataraces and deadlocks. Finally, we extend the existing FreeRTOS Windows simulator to simulate our multicore version of FreeRTOS, and evaluate its performance on some demo applications. |
3. | Divakaran, Sumesh; D’Souza, Deepak; Sridhar, Nigamanth Efficient refinement checking in VCC Conference Proceedings of the 6th Working Conference on Verified Software: Theories, Tools and Experiments (VSTTE), 17.-18.07.14, Vienna (Austria), Lecture Notes in Computer ScienceLecture Notes in Computer Science 2014. @conference{Divakaran2014, title = {Efficient refinement checking in VCC}, author = {Sumesh Divakaran and Deepak D’Souza and Nigamanth Sridhar}, doi = {10.1007/978-3-319-12154-3_2}, year = {2014}, date = {2014-10-14}, booktitle = {Proceedings of the 6th Working Conference on Verified Software: Theories, Tools and Experiments (VSTTE), 17.-18.07.14, Vienna (Austria)}, pages = {21-36}, series = {Lecture Notes in Computer ScienceLecture Notes in Computer Science}, abstract = {We propose a methodology for carrying out refinement proofs across declarative abstract models and concrete implementations in C, using the VCC verification tool. The main idea is to first perform a systematic translation from the top-level abstract model to a ghost implementation in VCC. Subsequent refinement proofs between successively refined abstract models and between abstract and concrete implementations are carried out in VCC. We propose an efficient technique to carry out these refinement checks in VCC. We illustrate our methodology with a case study in which we verify a simplified C implementation of an RTOS scheduler, with respect to its abstract Z specification. Overall, our methodology leads to efficient and automatic refinement proofs for complex systems that would typically be beyond the capability of tools such as Z/Eves or Rodin.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } We propose a methodology for carrying out refinement proofs across declarative abstract models and concrete implementations in C, using the VCC verification tool. The main idea is to first perform a systematic translation from the top-level abstract model to a ghost implementation in VCC. Subsequent refinement proofs between successively refined abstract models and between abstract and concrete implementations are carried out in VCC. We propose an efficient technique to carry out these refinement checks in VCC. We illustrate our methodology with a case study in which we verify a simplified C implementation of an RTOS scheduler, with respect to its abstract Z specification. Overall, our methodology leads to efficient and automatic refinement proofs for complex systems that would typically be beyond the capability of tools such as Z/Eves or Rodin. |
- Zero energy smart building
Principal Investigator: Joy Kuri (Department of Electronic System Engineering)
The Zero Energy Building project had two principal objectives: (a) To use renewable energy sources to meet, at least in part, the energy requirements of a building, and (b) to retrofit this capability to an existing building, with no structural changes allowed. A two-pronged approach was used: To exploit solar photovoltaics, and to implement load management to reduce energy demand.
The solution incorporated several novel features. On the supply side, the traditional inductor stage used in interfacing the transformer to the grid was eliminated completely — instead, the leakage inductance of the transformer was utilized; this lead to significant savings in weight and space. On the demand side, load management is the key requirement, and an elaborate measurement and control infrastructure has been developed. This consists of Load Management Units (LMU-s, one in each lab or office) that provide aggregate measurement and control functionality, a smart meter for pluggable loads with communication and storage capabilities called the Joule Jotter, and a Master Energy Consumption Scheduler, that collects measurements from LMU-s and Joule Jotters and makes load scheduling decisions, taking into account time-of-day energy prices, available solar energy as well as user convenience.
LMU-s and the master communicate using the DNP v3.0 protocol. Keeping the goal of retrofitting in mind, a Smart Switch that can be substituted for the traditional 2-terminal wall switch, has been developed. The Smart Switch can respond to commands from a remote controller sent via the power line (PLC) or via a wireless link. The challenge here is to provide power to the electronics inside the switch from the two terminals – line and load point – that are available at the switch; in particular, the neutral is not available.
The complete solution was designed and implemented in the Department of Electronic Systems Engineering, Indian Institute of Science Bangalore. It is operational and provides an average of 70 KWh of energy per day.
Project Publications
1. | Rao, Mannam Rama; Kuri, Joy; Prabhakar, T V Towards optimal load management with day-ahead pricing Conference Proceedings of the 7th International Conference on Communication Systems and Networks (COMSNETS), 06.-10.01.15, Bangalore, 2015. @conference{Rao2015, title = {Towards optimal load management with day-ahead pricing}, author = {Mannam Rama Rao and Joy Kuri and T. V. Prabhakar}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/07098699.pdf}, doi = {10.1109/COMSNETS.2015.7098699}, year = {2015}, date = {2015-05-04}, booktitle = {Proceedings of the 7th International Conference on Communication Systems and Networks (COMSNETS), 06.-10.01.15, Bangalore}, abstract = {Demand Response is under implementation throughout the globe by many utilities to incorporate the end user as an active player in reducing supply-demand imbalances. Day-ahead pricing is provided as an option to schedule electric loads so as to take advantage of time-varying prices. However, user convenience is also a factor that must be taken into account, as users may be willing to forego some savings to reduce inconvenience. We formulate an optimal scheduling problem considering both aspects. As the search space is exponentially large, we propose two greedy algorithms to find good schedules. To assess performance, we obtain the optimal schedule via Markov Chain Monte Carlo (MCMC) based simulations. We apply the framework to two case studies; one study uses appliance energy profiles obtained by actual measurements using the Joule Jotter, a device designed and developed in-house. Results indicate that the proposed algorithms perform very well, achieving performance within 10% of the optimal.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } Demand Response is under implementation throughout the globe by many utilities to incorporate the end user as an active player in reducing supply-demand imbalances. Day-ahead pricing is provided as an option to schedule electric loads so as to take advantage of time-varying prices. However, user convenience is also a factor that must be taken into account, as users may be willing to forego some savings to reduce inconvenience. We formulate an optimal scheduling problem considering both aspects. As the search space is exponentially large, we propose two greedy algorithms to find good schedules. To assess performance, we obtain the optimal schedule via Markov Chain Monte Carlo (MCMC) based simulations. We apply the framework to two case studies; one study uses appliance energy profiles obtained by actual measurements using the Joule Jotter, a device designed and developed in-house. Results indicate that the proposed algorithms perform very well, achieving performance within 10% of the optimal. |
Patent Application
Umanand, Loganathan; Karthik, A.: Energy-harvesting electronic switch, Indian Patent Application No. 4110/CHE/2015
Projects completed in 2014
- An interactive gateway for relaying physiological parameters and video data between mobile ambulances and hospitals (AMBULET)
Principal Investigator: Malati Hegde (Department of Electrical Communication Engineering)
“AMBULET” is an interactive gateway for relaying physiological parameters and video data between mobile ambulances and the health practitioners/hospitals. Nearly 51% of accident–related deaths occur due to inadequate medical attention during transportation to the hospital. AMBULET supports multiple streams of multiplexed real-time data transport using associated application proxies over a set of bonded channels to transparently and dynamically maintain desired levels of service quality over the cellular communications infrastructure.
Project Publications
1. | Kumaresh, D; Suhas, N; Krishna, Garge Gopi S; Anand, S V R; Hedge, Malati SeaMoX: A seamless mobility management scheme for real-time multimedia traffic over cellular networks Conference Proceedings of 2nd International Symposium on Signal Processing and Intelligent Recognition Systems (SIRS), India, Advances in Intelligent Systems and Computing 2015. @conference{Kumaresh2015, title = {SeaMoX: A seamless mobility management scheme for real-time multimedia traffic over cellular networks}, author = {D. Kumaresh and N. Suhas and S. Garge Gopi Krishna and S. V. R. Anand and Malati Hedge}, doi = {10.1007/978-3-319-28658-7_59}, year = {2015}, date = {2015-12-19}, booktitle = {Proceedings of 2nd International Symposium on Signal Processing and Intelligent Recognition Systems (SIRS), India}, pages = {699-710}, series = {Advances in Intelligent Systems and Computing}, abstract = {Real-time multimedia applications are often deployed to provide critical information in situations such as news coverage of an event or an incident or an ambulance rushing to provide emergency care. Mobile cellular coverage and performance of a provider network varies both spatially and temporally and challenges the ability of the network to support uninterrupted network access and application continuity. We propose that inter-provider handoffs could alleviate this problem, given the recent proliferation of Dual SIM Dual Active (DSDA) devices and the possibility of Multi SIM Multi Active devices by configuring laptops with multiple wireless broadband connections. We propose an application QoS aware mobility management approach. The software implementation is termed as SeaMoX and based on SeaMo+, an earlier implementation. We use live video streaming as an example application and demonstrate the impact of network selection and handoff by examining the playback at the receiver, which uses an adaptive jitter buffer algorithm.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } Real-time multimedia applications are often deployed to provide critical information in situations such as news coverage of an event or an incident or an ambulance rushing to provide emergency care. Mobile cellular coverage and performance of a provider network varies both spatially and temporally and challenges the ability of the network to support uninterrupted network access and application continuity. We propose that inter-provider handoffs could alleviate this problem, given the recent proliferation of Dual SIM Dual Active (DSDA) devices and the possibility of Multi SIM Multi Active devices by configuring laptops with multiple wireless broadband connections. We propose an application QoS aware mobility management approach. The software implementation is termed as SeaMoX and based on SeaMo+, an earlier implementation. We use live video streaming as an example application and demonstrate the impact of network selection and handoff by examining the playback at the receiver, which uses an adaptive jitter buffer algorithm. |
- Development of a smart-camera based optofluidic microscope for Malaria detection
Principal Investigator: Sai Siva Gorthi (Department of Instrumentation and Applied Physics)
In this project, we developed an “imaging” based point-of-care diagnostic device, which can fully-automate the complete work flow of conventional clinical microscopy. A custom designed portable digital microscope augmented with dedicated microfluidic lab-on-chips enables process automation, as well as, cost effective implementation of microscopic diagnosis of malaria. Such an inexpensive, portable and easy-to-use diagnostic device, which requires minimal skilled human intervention, greatly enhances the quality of health-care available to the rural population of the world.
Project Publications
1. | Srinivasan, Rajesh; Umesh, Sharath; Murali, Swetha; Asokan, Sundarrajan; Gorthi, Sai Siva Bare Fiber Bragg grating immunosensor for real‐time detection of Escherichia coli bacteria Journal Article Journal of Biophotonics, 10 (2), pp. 224-230, 2017. @article{Srinivasan2017, title = {Bare Fiber Bragg grating immunosensor for real‐time detection of Escherichia coli bacteria }, author = {Rajesh Srinivasan and Sharath Umesh and Swetha Murali and Sundarrajan Asokan and Sai Siva Gorthi}, url = {http://www.rbccps.org/wp-content/uploads/2018/12/Srinivasan_et_al-2016-Journal_of_Biophotonics.pdf}, doi = {10.1002/jbio.201500208}, year = {2017}, date = {2017-02-28}, journal = {Journal of Biophotonics}, volume = {10}, number = {2}, pages = {224-230}, abstract = {Escherichia coli (E. coli) bacteria have been identified to be the cause of variety of health outbreaks resulting from contamination of food and water. Timely and rapid detection of the bacteria is thus crucial to maintain desired quality of food products and water resources. A novel methodology proposed in this paper demonstrates for the first time, the feasibility of employing a bare fiber Bragg grating (bFBG) sensor for detection of E. coli bacteria. The sensor was fabricated in a photo‐sensitive optical fiber (4.2 µm/80 µm). Anti‐E. coli antibody was immobilized on the sensor surface to enable the capture of target cells/bacteria present in the sample solution. Strain induced on the sensor surface as a result of antibody immobilization and subsequent binding of E. coli bacteria resulted in unique wavelength shifts in the respective recording of the reflected Bragg wavelength, which can be exploited for the application of biosensing. Functionalization and antibody binding on to the fiber surface was cross validated by the color development resulting from the reaction of an appropriate substrate solution with the enzyme label conjugated to the anti‐E. coli antibody. Scanning electron microscope image of the fiber, further verified the E. coli cells bound to the antibody immobilized sensor surface. }, keywords = {}, pubstate = {published}, tppubtype = {article} } Escherichia coli (E. coli) bacteria have been identified to be the cause of variety of health outbreaks resulting from contamination of food and water. Timely and rapid detection of the bacteria is thus crucial to maintain desired quality of food products and water resources. A novel methodology proposed in this paper demonstrates for the first time, the feasibility of employing a bare fiber Bragg grating (bFBG) sensor for detection of E. coli bacteria. The sensor was fabricated in a photo‐sensitive optical fiber (4.2 µm/80 µm). Anti‐E. coli antibody was immobilized on the sensor surface to enable the capture of target cells/bacteria present in the sample solution. Strain induced on the sensor surface as a result of antibody immobilization and subsequent binding of E. coli bacteria resulted in unique wavelength shifts in the respective recording of the reflected Bragg wavelength, which can be exploited for the application of biosensing. Functionalization and antibody binding on to the fiber surface was cross validated by the color development resulting from the reaction of an appropriate substrate solution with the enzyme label conjugated to the anti‐E. coli antibody. Scanning electron microscope image of the fiber, further verified the E. coli cells bound to the antibody immobilized sensor surface. |
2. | Daniel, Kiruba S C G; Julius, Lourdes Albina Nirupa; Gorthi, Sai Siva Instantaneous detection of melamine by interference biosynthesis of silver nanoparticles Journal Article Sensors and Actuators B: Chemical, 238 , pp. 641-650, 2017. @article{Daniel2017b, title = {Instantaneous detection of melamine by interference biosynthesis of silver nanoparticles}, author = {S. C. G. Kiruba Daniel and Lourdes Albina Nirupa Julius and Sai Siva Gorthi}, url = {http://www.rbccps.org/wp-content/uploads/2018/12/1-s2.0-S092540051631156X-main.pdf}, doi = {10.1016/j.snb.2016.07.112}, year = {2017}, date = {2017-01-31}, journal = {Sensors and Actuators B: Chemical}, volume = {238}, pages = {641-650}, abstract = {Instantaneous detection of melamine, a potential milk adulterant has been demonstrated at room temperature by means of interference biosynthesis of silver nanoparticles. The sensing mechanism is based on the colorimetric change observed during the synthesis of silver nanoparticles due to the presence of melamine added during the biosynthesis. Presence and absence of melamine led to either inhibition of nanoparticle formation or enable partial synthesis of nanoparticles which is detected spectrally. A limit of detection (LOD) of 0.1 ppm in water and 0.5 ppm in raw milk was detected by the proposed technique at room temperature. UV–vis spectroscopy and High Resolution Transmission Electron Microscopy (HR-TEM) have been used to detect the spectral Surface Plasmon Resonance (SPR) and morphological changes of synthesized silver nanoparticle with and without the presence of the analyte melamine. Further, interference synthesis based sensing of melamine was done with caffeic acid as a reducing agent which confirms the role of caffeic acid a major constituent of Parthenium leaf extract for interference biosynthesis based sensing. Melamine is detected from raw milk by interference biosynthesis based sensing after a facile milk pre-processing step. Thus the method can be converted into a workable handheld prototype for detection of melamine for in-situ field applications.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Instantaneous detection of melamine, a potential milk adulterant has been demonstrated at room temperature by means of interference biosynthesis of silver nanoparticles. The sensing mechanism is based on the colorimetric change observed during the synthesis of silver nanoparticles due to the presence of melamine added during the biosynthesis. Presence and absence of melamine led to either inhibition of nanoparticle formation or enable partial synthesis of nanoparticles which is detected spectrally. A limit of detection (LOD) of 0.1 ppm in water and 0.5 ppm in raw milk was detected by the proposed technique at room temperature. UV–vis spectroscopy and High Resolution Transmission Electron Microscopy (HR-TEM) have been used to detect the spectral Surface Plasmon Resonance (SPR) and morphological changes of synthesized silver nanoparticle with and without the presence of the analyte melamine. Further, interference synthesis based sensing of melamine was done with caffeic acid as a reducing agent which confirms the role of caffeic acid a major constituent of Parthenium leaf extract for interference biosynthesis based sensing. Melamine is detected from raw milk by interference biosynthesis based sensing after a facile milk pre-processing step. Thus the method can be converted into a workable handheld prototype for detection of melamine for in-situ field applications. |
3. | Daniel, Kiruba S C G; Julius, Lourdes Albina Nirupa; Gorthi, Sai Siva Microfluidics based handheld nanoparticle synthesizer Journal Article Journal of Cluster Science, 28 (3), pp. 1201-1213, 2017. @article{Daniel2017, title = {Microfluidics based handheld nanoparticle synthesizer}, author = {S. C. G. Kiruba Daniel and Lourdes Albina Nirupa Julius and Sai Siva Gorthi}, url = {http://www.rbccps.org/wp-content/uploads/2018/12/KirubaDaniel2017_Article_MicrofluidicsBasedHandheldNano.pdf}, doi = {10.1007/s10876-016-1120-x}, year = {2017}, date = {2017-05-31}, journal = {Journal of Cluster Science}, volume = {28}, number = {3}, pages = {1201-1213}, abstract = {Current study relates to the development of an electrical power-free, handheld microfluidic nanoparticle synthesizer for synthesis of uniform sized silver nanoparticles at room temperature. The synthesizer module consists of a custom designed microreactor and employs negative pressure based pumping mechanism for the electrical power free synthesis of metal nanoparticles. In order to realize a microreactor capable of on-site synthesis of monodisperse nanoparticles, optimization studies by bulk biosynthesis at varying ratios of the precursor and the reducing agent followed by UV–VIS absorption studies were performed to determine the appropriate mixing ratio. Later, a custom designed microfluidic micromixer was used to perform volumetric flow rate optimizations at the desired ratio using syringe pumps. From the knowledge of the precursor and reducing agent ratio and the flow rates, we modified the hydraulic resistance of micro-mixer inlets by varying the channel geometry to meet the optimized specifications leading to effective synthesis. The synthesized nanoparticles were characterized by UV–VIS spectroscopy, XPS, FTIR, EDS, HRTEM and SAED. The crystal lattice planes of [111] and [220] from the SAED pattern confirms the presence of silver nanoparticles. HRTEM study elucidates that the size of the synthesized nanoparticles is between 2 and 10 nm.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Current study relates to the development of an electrical power-free, handheld microfluidic nanoparticle synthesizer for synthesis of uniform sized silver nanoparticles at room temperature. The synthesizer module consists of a custom designed microreactor and employs negative pressure based pumping mechanism for the electrical power free synthesis of metal nanoparticles. In order to realize a microreactor capable of on-site synthesis of monodisperse nanoparticles, optimization studies by bulk biosynthesis at varying ratios of the precursor and the reducing agent followed by UV–VIS absorption studies were performed to determine the appropriate mixing ratio. Later, a custom designed microfluidic micromixer was used to perform volumetric flow rate optimizations at the desired ratio using syringe pumps. From the knowledge of the precursor and reducing agent ratio and the flow rates, we modified the hydraulic resistance of micro-mixer inlets by varying the channel geometry to meet the optimized specifications leading to effective synthesis. The synthesized nanoparticles were characterized by UV–VIS spectroscopy, XPS, FTIR, EDS, HRTEM and SAED. The crystal lattice planes of [111] and [220] from the SAED pattern confirms the presence of silver nanoparticles. HRTEM study elucidates that the size of the synthesized nanoparticles is between 2 and 10 nm. |
4. | Julius, Lourdes Albina Nirupa; Jagannadh, Veerendra Kalyan; Michael, Issac J; Srinivasan, Rajesh; Gorthi, Sai Siva Design and validation of on-chip planar mixer based on advection and viscoelastic effects Journal Article BioChip Journal, 10 (1), pp. 16-24, 2016. @article{Julius2016, title = {Design and validation of on-chip planar mixer based on advection and viscoelastic effects}, author = {Lourdes Albina Nirupa Julius and Veerendra Kalyan Jagannadh and Issac J. Michael and Rajesh Srinivasan and Sai Siva Gorthi}, url = {http://www.rbccps.org/wp-content/uploads/2018/12/Julius2016_Article_DesignAndValidationOfOn-chipPl.pdf}, doi = {10.1007/s13206-016-0103-1}, year = {2016}, date = {2016-03-31}, journal = {BioChip Journal}, volume = {10}, number = {1}, pages = {16-24}, abstract = {Mixing at low Reynolds number is usually due to diffusion and requires longer channel lengths for complete mixing. In order to reduce the mixing lengths, advective flow can be induced by varying the channel geometry. Additionally, in non-newtonian fluids, appropriate modifications to channel geometry can be used to aid the mixing process by capitalizing on their viscoelastic nature. Here we have exploited the advection and viscoelastic effects to implement a planar passive micro-mixer. Microfluidic devices incorporating different blend of mixing geometries were conceived. The optimum design was chosen based on the results of the numerical simulations performed in COMSOL. The chosen design had sudden expansion and contraction along with teeth patterns along the channel walls to improve mixing. Mixing of two different dyes was performed to validate the mixing efficiency. Particle dispersion experiments were also carried out. The results indicated effective mixing. In addition, the same design was also found to be compatible with electrical power free pumping mechanism like suction. The proposed design was then used to carry out on-chip chemical cell lysis with human whole blood samples to establish its use with non-newtonian fluids. Complete lysis of the erythrocytes was observed leaving behind the white blood cells at the outlet.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Mixing at low Reynolds number is usually due to diffusion and requires longer channel lengths for complete mixing. In order to reduce the mixing lengths, advective flow can be induced by varying the channel geometry. Additionally, in non-newtonian fluids, appropriate modifications to channel geometry can be used to aid the mixing process by capitalizing on their viscoelastic nature. Here we have exploited the advection and viscoelastic effects to implement a planar passive micro-mixer. Microfluidic devices incorporating different blend of mixing geometries were conceived. The optimum design was chosen based on the results of the numerical simulations performed in COMSOL. The chosen design had sudden expansion and contraction along with teeth patterns along the channel walls to improve mixing. Mixing of two different dyes was performed to validate the mixing efficiency. Particle dispersion experiments were also carried out. The results indicated effective mixing. In addition, the same design was also found to be compatible with electrical power free pumping mechanism like suction. The proposed design was then used to carry out on-chip chemical cell lysis with human whole blood samples to establish its use with non-newtonian fluids. Complete lysis of the erythrocytes was observed leaving behind the white blood cells at the outlet. |
5. | Jagannadh, Veerendra Kalyan; Bhat, Bindu Prabhath; Julius, Lourdes Albina Nirupa; Gorthi, Sai Siva High-throughput miniaturized microfluidic microscopy with radially parallelized channel geometry Journal Article Analytical and Bioanalytical Chemistry, 408 (7), pp. 1909-1916, 2016. @article{Jagannadh2016, title = {High-throughput miniaturized microfluidic microscopy with radially parallelized channel geometry}, author = {Veerendra Kalyan Jagannadh and Bindu Prabhath Bhat and Lourdes Albina Nirupa Julius and Sai Siva Gorthi}, url = {http://www.rbccps.org/wp-content/uploads/2018/12/Jagannadh2016_Article_High-throughputMiniaturizedMic.pdf}, doi = {10.1007/s00216-015-9301-2}, year = {2016}, date = {2016-03-31}, journal = {Analytical and Bioanalytical Chemistry}, volume = {408}, number = {7}, pages = {1909-1916}, abstract = {In this article, we present a novel approach to throughput enhancement in miniaturized microfluidic microscopy systems. Using the presented approach, we demonstrate an inexpensive yet high-throughput analytical instrument. Using the high-throughput analytical instrument, we have been able to achieve about 125,880 cells per minute (more than one hundred and twenty five thousand cells per minute), even while employing cost-effective low frame rate cameras (120 fps). The throughput achieved here is a notable progression in the field of diagnostics as it enables rapid quantitative testing and analysis. We demonstrate the applicability of the instrument to point-of-care diagnostics, by performing blood cell counting. We report a comparative analysis between the counts (in cells per μl) obtained from our instrument, with that of a commercially available hematology analyzer.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this article, we present a novel approach to throughput enhancement in miniaturized microfluidic microscopy systems. Using the presented approach, we demonstrate an inexpensive yet high-throughput analytical instrument. Using the high-throughput analytical instrument, we have been able to achieve about 125,880 cells per minute (more than one hundred and twenty five thousand cells per minute), even while employing cost-effective low frame rate cameras (120 fps). The throughput achieved here is a notable progression in the field of diagnostics as it enables rapid quantitative testing and analysis. We demonstrate the applicability of the instrument to point-of-care diagnostics, by performing blood cell counting. We report a comparative analysis between the counts (in cells per μl) obtained from our instrument, with that of a commercially available hematology analyzer. |
6. | Jagannadh, Veerendra Kalyan; Srinivasan, Rajesh; Gorthi, Sai Siva A semi-automated, field-portable microscopy platform for clinical diagnostic applications Journal Article AIP Advances, 5 (8), 2015. @article{Jagannadh2015b, title = {A semi-automated, field-portable microscopy platform for clinical diagnostic applications}, author = {Veerendra Kalyan Jagannadh and Rajesh Srinivasan and Sai Siva Gorthi}, doi = {10.1063/1.4915133}, year = {2015}, date = {2015-03-24}, journal = {AIP Advances}, volume = {5}, number = {8}, abstract = {Clinical microscopy is a versatile diagnostic platform used for diagnosis of a multitude of diseases. In the recent past, many microfluidics based point-of-care diagnostic devices have been developed, which serve as alternatives to microscopy. However, these point-of-care devices are not as multi-functional and versatile as clinical microscopy. With the use of custom designed optics and microfluidics, we have developed a versatile microscopy-based cellular diagnostic platform, which can be used at the point of care. The microscopy platform presented here is capable of detecting infections of very low parasitemia level (in a very small quantity of sample), without the use of any additional computational hardware. Such a cost-effective and portable diagnostic device, would greatly impact the quality of health care available to people living in rural locations of the world. Apart from clinical diagnostics, it’s applicability to field research in environmental microbiology has also been outlined.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Clinical microscopy is a versatile diagnostic platform used for diagnosis of a multitude of diseases. In the recent past, many microfluidics based point-of-care diagnostic devices have been developed, which serve as alternatives to microscopy. However, these point-of-care devices are not as multi-functional and versatile as clinical microscopy. With the use of custom designed optics and microfluidics, we have developed a versatile microscopy-based cellular diagnostic platform, which can be used at the point of care. The microscopy platform presented here is capable of detecting infections of very low parasitemia level (in a very small quantity of sample), without the use of any additional computational hardware. Such a cost-effective and portable diagnostic device, would greatly impact the quality of health care available to people living in rural locations of the world. Apart from clinical diagnostics, it’s applicability to field research in environmental microbiology has also been outlined. |
7. | Jagannadh, Veerendra Kalyan; Adhikari, Jayesh Vasudeva; Gorthi, Sai Siva Automated cell viability assessment using a microfluidics based portable imaging flow analyzer Journal Article AIP Biomicrofluids, 9 (2), 2015. @article{Jagannadh2015b, title = {Automated cell viability assessment using a microfluidics based portable imaging flow analyzer}, author = {Veerendra Kalyan Jagannadh and Jayesh Vasudeva Adhikari and Sai Siva Gorthi}, doi = {10.1063/1.4919402}, year = {2015}, date = {2015-04-28}, journal = {AIP Biomicrofluids}, volume = {9}, number = {2}, abstract = {In this work, we report a system-level integration of portable microscopy and microfluidics for the realization of optofluidic imaging flow analyzer with a throughput of 450 cells/s. With the use of a cellphone augmented with off-the-shelf optical components and custom designed microfluidics, we demonstrate a portable optofluidic imaging flow analyzer. A multiple microfluidic channel geometry was employed to demonstrate the enhancement of throughput in the context of low frame-rate imaging systems. Using the cell-phone based digital imaging flow analyzer, we have imaged yeast cells present in a suspension. By digitally processing the recorded videos of the flow stream on the cellphone, we demonstrated an automated cell viability assessment of the yeast cell population. In addition, we also demonstrate the suitability of the system for blood cell counting.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this work, we report a system-level integration of portable microscopy and microfluidics for the realization of optofluidic imaging flow analyzer with a throughput of 450 cells/s. With the use of a cellphone augmented with off-the-shelf optical components and custom designed microfluidics, we demonstrate a portable optofluidic imaging flow analyzer. A multiple microfluidic channel geometry was employed to demonstrate the enhancement of throughput in the context of low frame-rate imaging systems. Using the cell-phone based digital imaging flow analyzer, we have imaged yeast cells present in a suspension. By digitally processing the recorded videos of the flow stream on the cellphone, we demonstrated an automated cell viability assessment of the yeast cell population. In addition, we also demonstrate the suitability of the system for blood cell counting. |
8. | Jagannadh, Veerendra Kalyan; Murthy, Rashmi Sreeramachandra; Srinivasan, Rajesh; Gorthi, Sai Siva Automated quantitative cytological analysis using portable microfluidic microscopy Journal Article Journal of Biophotonics, 9 (6), pp. 586-595, 2015. @article{Jagannadh2015, title = {Automated quantitative cytological analysis using portable microfluidic microscopy}, author = {Veerendra Kalyan Jagannadh and Rashmi Sreeramachandra Murthy and Rajesh Srinivasan and Sai Siva Gorthi}, doi = {10.1002/jbio.201500108}, year = {2015}, date = {2015-05-20}, journal = {Journal of Biophotonics}, volume = {9}, number = {6}, pages = {586-595}, abstract = {In this article, a portable microfluidic microscopy based approach for automated cytological investigations is presented. Inexpensive optical and electronic components have been used to construct a simple microfluidic microscopy system. In contrast to the conventional slide-based methods, the presented method employs microfluidics to enable automated sample handling and image acquisition. The approach involves the use of simple in-suspension staining and automated image acquisition to enable quantitative cytological analysis of samples. The applicability of the presented approach to research in cellular biology is shown by performing an automated cell viability assessment on a given population of yeast cells. Further, the relevance of the presented approach to clinical diagnosis and prognosis has been demonstrated by performing detection and differential assessment of malaria infection in a given sample.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this article, a portable microfluidic microscopy based approach for automated cytological investigations is presented. Inexpensive optical and electronic components have been used to construct a simple microfluidic microscopy system. In contrast to the conventional slide-based methods, the presented method employs microfluidics to enable automated sample handling and image acquisition. The approach involves the use of simple in-suspension staining and automated image acquisition to enable quantitative cytological analysis of samples. The applicability of the presented approach to research in cellular biology is shown by performing an automated cell viability assessment on a given population of yeast cells. Further, the relevance of the presented approach to clinical diagnosis and prognosis has been demonstrated by performing detection and differential assessment of malaria infection in a given sample. |
9. | Jagannadh, Veerendra Kalyan; Mackenzie, Mark D; Pal, Parama; Kar, Ajoy K; Gorthi, Sai Siva Imaging flow cytometry with femtosecond laser-micromachined glass microfluidic channels Journal Article IEEE Journal of Selected Topics in Quantum Electronics, 21 (4), 2015. @article{Jagannadh2015b, title = {Imaging flow cytometry with femtosecond laser-micromachined glass microfluidic channels}, author = {Veerendra Kalyan Jagannadh and Mark D. Mackenzie and Parama Pal and Ajoy K. Kar and Sai Siva Gorthi}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/06990492.pdf}, doi = {10.1109/JSTQE.2014.2382978}, year = {2015}, date = {2015-08-31}, journal = {IEEE Journal of Selected Topics in Quantum Electronics}, volume = {21}, number = {4}, abstract = {Microfluidic/optofluidic microscopy is a versatile modality for imaging and analyzing properties of cells/particles while they are in flow. In this paper, we demonstrate the integration of fused silica microfluidics fabricated using femtosecond laser machining into optofluidic imaging systems. By using glass for the sample stage of our microscope, we have exploited its superior optical quality for imaging and bio-compatibility. By integrating these glass microfluidic devices into a custom-built bright field microscope, we have been able to image red blood cells in flow with high-throughputs and good fidelity. In addition, we also demonstrate imaging as well as detection of fluorescent beads with these microfluidic devices.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Microfluidic/optofluidic microscopy is a versatile modality for imaging and analyzing properties of cells/particles while they are in flow. In this paper, we demonstrate the integration of fused silica microfluidics fabricated using femtosecond laser machining into optofluidic imaging systems. By using glass for the sample stage of our microscope, we have exploited its superior optical quality for imaging and bio-compatibility. By integrating these glass microfluidic devices into a custom-built bright field microscope, we have been able to image red blood cells in flow with high-throughputs and good fidelity. In addition, we also demonstrate imaging as well as detection of fluorescent beads with these microfluidic devices. |
10. | Jagannadh, Veerendra Kalyan; Mackenzie, Mark D; Pal, Parama; Kar, Ajoy K; Gorthi, Sai Siva Optofluidic microscopy using femtosecond micromachined glass microfluidics Conference Proceedings of the 12th International Conference on Fibre Optics and Photonics, 13.-16.12.14, Kharagpur, 2014. @conference{Jagannadh2014, title = {Optofluidic microscopy using femtosecond micromachined glass microfluidics}, author = {Veerendra Kalyan Jagannadh and Mark D. Mackenzie and Parama Pal and Ajoy K. Kar and Sai Siva Gorthi}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/Photonics-2014-T3A.6.pdf}, doi = {10.1364/PHOTONICS.2014.T3A.6}, year = {2014}, date = {2014-12-16}, booktitle = {Proceedings of the 12th International Conference on Fibre Optics and Photonics, 13.-16.12.14, Kharagpur}, abstract = {Optofluidic microscopy is a versatile modality for imaging and analyzing particles and their properties in flow. In this paper, we demonstrate the applicability of microfluidic devices fabricated using femtosecond laser machining in fused silica for integration into optofluidic imaging systems. In addition, glass, being chemically inert, robust, and inexpensive, is ideal for field-deployable prototypes. By using glass for the sample handling component of our microscope, we are able to exploit its superior optical quality for imaging and biocompatibility. By integrating these glass microfluidic devices into a custom-built bright field microscope, we have been able to analyze red blood cells in flow with good fidelity.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } Optofluidic microscopy is a versatile modality for imaging and analyzing particles and their properties in flow. In this paper, we demonstrate the applicability of microfluidic devices fabricated using femtosecond laser machining in fused silica for integration into optofluidic imaging systems. In addition, glass, being chemically inert, robust, and inexpensive, is ideal for field-deployable prototypes. By using glass for the sample handling component of our microscope, we are able to exploit its superior optical quality for imaging and biocompatibility. By integrating these glass microfluidic devices into a custom-built bright field microscope, we have been able to analyze red blood cells in flow with good fidelity. |
Patent Applications
Gorthi, Sai Siva; Jagammadh, Veerendra Kalyan: A microscopy system and method for analysing fluids, Indian Patent Application No. 2432/CHE/2014 (15.01.16), PCT Application No. PCT/IB2015/053581
Gorthi, Sai Siva; Daniel, S. C. G. Kiruba; Nirupa, L. Albina: Microfludics based on-chip biosynthesis of metal nanoparticles at room temperature, Indian Patent Application No. 3649/CHE/2015 (20.01.17)
Gorthi, Sai Siva: A real-time sample classifier, Indian Patent Application No. 4110/CHE/2015
Gorthi, Sai Siva
A microfluidic cartridge
Indian Patent Application No. 4229/CHE/2015
Gorthi, Sai Siva; Daniel, S. C. G. Kiruba; Nirupa, L. Albina
Real-time sensing of analytes by on-chip interference-synthesis of noble metal nanoparticles
Indian Patent Application No. 4882/CHE/2015
- Low-cost, efficient and portable blood cell counter for point-of-care diagnostics
Principal Investigator: V. Kumaran (Department of Chemical Engineering)
This project addressed two critical technologies for performing complete blood counts for health diagnostics. The technologies include the rapid mixing of samples and reagents in channels of small dimensions and impedance measurements across these channels to measure and characterize the cells flowing through them. The process workflow is completely automated (liquid injection, mixing and handling processes such as lysing and quenching) and novel approaches have been adopted to fabricate miniature (less than a hundred microns) electrodes in the walls of the channels. This technology is currently being spun-off as a startup (MicroX Labs).
- Smart phone interferometer
Principal Investigator: Manoj Varma (Centre for Nano Science and Engineering)
A micro-diffractive structure patterned on a thin film surface enables the differential read-out of phase and amplitude change caused due to the molecular adsorption on the surface with a limit of detection as low as 3×10-6 RIU (refractive index units equivalent to an optical thickness of about 10 picometers) comparable to dominant techniques such as Surface Plasmon Resonance (SPR). This technique also allows the measurement of molecular binding kinetics similar to SPR.
Our implementation was based on transmission mode measurements and therefore enabled the use of low cost CMOS imagers, e.g. mobile phone cameras, to be used for interferometric measurements of molecular adsorption or refractive index changes. Such devices are very beneficial for low cost point-of-care diagnostics among other applications. Interferometry is one of the most sensitive metrological technique available today and is being used to detect gravitational waves (LIGO project), which are one of the weakest phenomena known to mankind.
Implementing interferometry using our micro-fabricated devices attached on top of the camera of a smart phone was the first demonstration of the mobile phone as a sophisticated metrological tool. Our microfabricated device consists of photolithographically patterned glass surface consisting of microarrays of a specified depth designed to maximize the interferometric contrast. Any small refractive index (or thickness) perturbation on this device can be measured as a change in diffraction pattern which is captured by the mobile phone camera. As pointed earlier, this interferometric technique is comparable to existing optical bio-detection techniques such as SPR.
Project Publications
1. | Sasikumar, Harish; Varma, Manoj Detection limit for optically sensing specific protein interactions in free-solution Journal Article arXiv: Physics, 2017. @article{Sasikumar2017, title = {Detection limit for optically sensing specific protein interactions in free-solution}, author = {Harish Sasikumar and Manoj Varma}, url = {http://www.rbccps.org/wp-content/uploads/2018/12/1712.00224.pdf}, year = {2017}, date = {2017-12-01}, journal = {arXiv: Physics}, abstract = {Optical molecular sensing techniques are often limited by the refractive index change associated with the probed interactions. In this work, we present a closed form analytical model to estimate the magnitude of optical refractive index change arising from protein-protein interactions. The model, based on the Maxwell Garnett effective medium theory and first order chemical kinetics serves as a general framework for estimating the detection limits of optical sensing of molecular interactions. The model is applicable to situations where one interacting species is immobilized to a surface, as commonly done, or to emerging techniques such as Back-Scattering Interferometry (BSI) where both interacting species are un-tethered. Our findings from this model point to the strong role of as yet unidentified factors in the origin of the BSI signal resulting in significant deviation from linear optical response. }, keywords = {}, pubstate = {published}, tppubtype = {article} } Optical molecular sensing techniques are often limited by the refractive index change associated with the probed interactions. In this work, we present a closed form analytical model to estimate the magnitude of optical refractive index change arising from protein-protein interactions. The model, based on the Maxwell Garnett effective medium theory and first order chemical kinetics serves as a general framework for estimating the detection limits of optical sensing of molecular interactions. The model is applicable to situations where one interacting species is immobilized to a surface, as commonly done, or to emerging techniques such as Back-Scattering Interferometry (BSI) where both interacting species are un-tethered. Our findings from this model point to the strong role of as yet unidentified factors in the origin of the BSI signal resulting in significant deviation from linear optical response. |
2. | Sasikumar, Harish; Varma, Manoj Exploiting transient phenomena for imaging with breath figures Journal Article Applied Physics Letters, 110 (7), pp. 071602:1-5, 2017. @article{Sasikumar2017b, title = {Exploiting transient phenomena for imaging with breath figures }, author = {Harish Sasikumar and Manoj Varma}, url = {http://www.rbccps.org/wp-content/uploads/2018/12/1.4976313.pdf}, doi = {10.1063/1.4976313}, year = {2017}, date = {2017-02-13}, journal = {Applied Physics Letters}, volume = {110}, number = {7}, pages = {071602:1-5}, abstract = {Breath figures refer to the patterns formed when vapor condenses into the liquid phase on a surface, revealing heterogeneities in topography or chemical composition. These figures are composed of micro-droplets, which scatter light and produce optical contrast. Differences in hydrophobicity imposed by surface features or contaminants result in a difference in micro-droplet densities, which has been used in applications such as substrate independent optical visualization of single layer graphene flakes. Here, we show that transient phenomena, such as the pinning transition of micro-droplets condensed over a polymer surface, can be used to enhance the optical contrast even when the time averaged difference in micro-droplet densities is not substantial. Thus, this work opens a new way of visualizing surface heterogeneities using transient phenomena occurring during condensation or evaporation of micro-droplets as opposed to only using time averaged differences in wettability due to the surface features.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Breath figures refer to the patterns formed when vapor condenses into the liquid phase on a surface, revealing heterogeneities in topography or chemical composition. These figures are composed of micro-droplets, which scatter light and produce optical contrast. Differences in hydrophobicity imposed by surface features or contaminants result in a difference in micro-droplet densities, which has been used in applications such as substrate independent optical visualization of single layer graphene flakes. Here, we show that transient phenomena, such as the pinning transition of micro-droplets condensed over a polymer surface, can be used to enhance the optical contrast even when the time averaged difference in micro-droplet densities is not substantial. Thus, this work opens a new way of visualizing surface heterogeneities using transient phenomena occurring during condensation or evaporation of micro-droplets as opposed to only using time averaged differences in wettability due to the surface features. |
3. | Sasikumar, Harish; Prasad, Vishnu; Pal, Parama; Varma, Manoj Diffractive interference optical analyzer (DiOPTER) Conference Proceedings of the 2016 SPIE International Conference Optical Diagnostics and Sensing XVI: Toward Point-of-Care Diagnostics, 13.02.16, San Francisco (USA), 9715 , 2016. @conference{Sasikumar2016, title = {Diffractive interference optical analyzer (DiOPTER)}, author = {Harish Sasikumar and Vishnu Prasad and Parama Pal and Manoj Varma}, doi = {10.1117/12.2211745}, year = {2016}, date = {2016-02-16}, booktitle = {Proceedings of the 2016 SPIE International Conference Optical Diagnostics and Sensing XVI: Toward Point-of-Care Diagnostics, 13.02.16, San Francisco (USA)}, volume = {9715}, abstract = {This report demonstrates a method for high-resolution refractometric measurements using, what we have termed as, a Diffractive Interference Optical Analyzer (DiOpter). The setup consists of a laser, polarizer, a transparent diffraction grating and Si-photodetectors. The sensor is based on the differential response of diffracted orders to bulk refractive index changes. In these setups, the differential read-out of the diffracted orders suppresses signal drifts and enables time-resolved determination of refractive index changes in the sample cell. A remarkable feature of this device is that under appropriate conditions, the measurement sensitivity of the sensor can be enhanced by more than two orders of magnitude due to interference between multiply reflected diffracted orders. A noise-equivalent limit of detection (LoD) of 6×10(-7) RIU was achieved in glass. This work focuses on devices with integrated sample well, made on low-cost PDMS. As the detection methodology is experimentally straightforward, it can be used across a wide array of applications, ranging from detecting changes in surface adsorbates via binding reactions to estimating refractive index (and hence concentration) variations in bulk samples. An exciting prospect of this technique is the potential integration of this device to smartphones using a simple interface based on transmission mode configuration. In a transmission configuration, we were able to achieve an LoD of 4×10(-4) RIU which is sufficient to explore several applications in food quality testing and related fields. We are envisioning the future of this platform as a personal handheld optical analyzer for applications ranging from environmental sensing to healthcare and quality testing of food products.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } This report demonstrates a method for high-resolution refractometric measurements using, what we have termed as, a Diffractive Interference Optical Analyzer (DiOpter). The setup consists of a laser, polarizer, a transparent diffraction grating and Si-photodetectors. The sensor is based on the differential response of diffracted orders to bulk refractive index changes. In these setups, the differential read-out of the diffracted orders suppresses signal drifts and enables time-resolved determination of refractive index changes in the sample cell. A remarkable feature of this device is that under appropriate conditions, the measurement sensitivity of the sensor can be enhanced by more than two orders of magnitude due to interference between multiply reflected diffracted orders. A noise-equivalent limit of detection (LoD) of 6×10(-7) RIU was achieved in glass. This work focuses on devices with integrated sample well, made on low-cost PDMS. As the detection methodology is experimentally straightforward, it can be used across a wide array of applications, ranging from detecting changes in surface adsorbates via binding reactions to estimating refractive index (and hence concentration) variations in bulk samples. An exciting prospect of this technique is the potential integration of this device to smartphones using a simple interface based on transmission mode configuration. In a transmission configuration, we were able to achieve an LoD of 4×10(-4) RIU which is sufficient to explore several applications in food quality testing and related fields. We are envisioning the future of this platform as a personal handheld optical analyzer for applications ranging from environmental sensing to healthcare and quality testing of food products. |
4. | Pal, Parama; Sasikumar, Harish; Varma, Manoj Label-free biosensing using diffractive optical analysis Conference Proceedings of the 13th International Conference on Fiber Optics and Photonics, 04.-06.12.16, Kanpur (India), 2016. @conference{Pal2016, title = {Label-free biosensing using diffractive optical analysis}, author = {Parama Pal and Harish Sasikumar and Manoj Varma}, doi = {10.1364/PHOTONICS.2016.Th2F.1}, year = {2016}, date = {2016-12-08}, booktitle = {Proceedings of the 13th International Conference on Fiber Optics and Photonics, 04.-06.12.16, Kanpur (India)}, abstract = {We demonstrate a biosensing technique based on high-resolution (~10-6 refractive index units) refractometric measurements for detecting time-resolved concentration variations in surface (due to the binding of adsorbates) as well as in bulk samples.}, keywords = {}, pubstate = {published}, tppubtype = {conference} } We demonstrate a biosensing technique based on high-resolution (~10-6 refractive index units) refractometric measurements for detecting time-resolved concentration variations in surface (due to the binding of adsorbates) as well as in bulk samples. |
5. | Kumawat, Nityanand; Pal, Parama; Varma, Manoj Diffractive optical analysis for refractive index sensing using transparent phase gratings Journal Article Nature Scientific Reports, 5 , 2015. @article{Kumawat2015, title = {Diffractive optical analysis for refractive index sensing using transparent phase gratings}, author = {Nityanand Kumawat and Parama Pal and Manoj Varma}, url = {http://www.rbccps.org/wp-content/uploads/2018/12/srep16687.pdf}, doi = {10.1038/srep16687}, year = {2015}, date = {2015-11-18}, journal = {Nature Scientific Reports}, volume = {5}, abstract = {We report the implementation of a micro-patterned, glass-based photonic sensing element that is capable of label-free biosensing. The diffractive optical analyzer is based on the differential response of diffracted orders to bulk as well as surface refractive index changes. The differential read-out suppresses signal drifts and enables time-resolved determination of refractive index changes in the sample cell. A remarkable feature of this device is that under appropriate conditions, the measurement sensitivity of the sensor can be enhanced by more than two orders of magnitude due to interference between multiply reflected diffracted orders. A noise-equivalent limit of detection (LoD) of 6 × 10^−7 was achieved with this technique with scope for further improvement.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We report the implementation of a micro-patterned, glass-based photonic sensing element that is capable of label-free biosensing. The diffractive optical analyzer is based on the differential response of diffracted orders to bulk as well as surface refractive index changes. The differential read-out suppresses signal drifts and enables time-resolved determination of refractive index changes in the sample cell. A remarkable feature of this device is that under appropriate conditions, the measurement sensitivity of the sensor can be enhanced by more than two orders of magnitude due to interference between multiply reflected diffracted orders. A noise-equivalent limit of detection (LoD) of 6 × 10^−7 was achieved with this technique with scope for further improvement. |
Projects completed in 2013
- Decentralized low power filtration via field effect – A water bottle for desalination
Principal Investigator: Sanjiv Sambandan (Department of Instrumentation and Applied Physics)
Waste water management is a global problem. Technologies based on membranes and chemicals to treat waste water place immense costs to the environment. This project focused on developing a membraneless, chemical free wastewater treatment system. The designs thus far have permitted easy scalability from hand held systems to larger community based systems. Tests have shown that submicron impurities such as metal oxides, coliform bacteria, organic impurities are removed. Hardness is also abated. Future plans include a user friendly design of a hand held water bottle and the setup of a pilot project for continuous larger throughput systems.
Patent Application
Sambadan, Sanjiv: A desalination device, Indian Patent Application No. 1506/CHE/2013 (03.06.16)
- Development of non-invasive human breath sensor system
Principal Investigator: K. Rajanna (Department of Instrumentation and Applied Physics)
A Polyvinylidene Difluoride (PVDF) based nasal sensor has been designed and developed to monitor human respiration, a novel and non‐invasive type sensor. The piezoelectric property of the PVDF film has been utilized to realise the sensor. In our work, we have used PVDF film in the cantilever configuration as a sensing element to form the nasal sensor. The dimensions of the PVDF cantilever sensing element are optimized using detailed theoretical analysis as well as experimental studies. Two identical PVDF sensors were mounted on a normal headphone such that the tidal flow of inhaled and exhale air impinge on the sensor in order to measure the breathing patterns. These patterns are recorded, filtered, analyzed and displayed on the computer screen. A necessary signal conditioning circuitry has been developed for the PVDF nasal sensors. Clinical trials were conducted at the nearby hospital to study the performance of the developed breath sensor. The results were analyzed and found very useful in identifying the breathing abnormalities.
Project Publications
1. | Manjunatha, Roopa G; Mahapatra, Roy D; Prakash, Surya; Rajanna, K Validation of polyvinylidene fluoride nasal sensor to assess nasal obstruction in comparison with subjective technique Journal Article American Journal of Otolaryngology: Head and Neck Medicine and Surgery, 36 (2), pp. 122-129, 2015. @article{Manjunatha2015, title = {Validation of polyvinylidene fluoride nasal sensor to assess nasal obstruction in comparison with subjective technique}, author = {G. Roopa Manjunatha and D. Roy Mahapatra and Surya Prakash and K. Rajanna}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/1-s2.0-S0196070914002063-main.pdf}, doi = {10.1016/j.amjoto.2014.09.002}, year = {2015}, date = {2015-04-30}, journal = {American Journal of Otolaryngology: Head and Neck Medicine and Surgery}, volume = {36}, number = {2}, pages = {122-129}, abstract = {The aim of this study is to validate the applicability of the PolyVinyliDene Fluoride (PVDF) nasal sensor to assess the nasal airflow, in healthy subjects and patients with nasal obstruction and to correlate the results with the score of Visual Analogue Scale (VAS). PVDF nasal sensor and VAS measurements were carried out in 50 subjects (25-healthy subjects and 25 patients). The VAS score of nasal obstruction and peak-to-peak amplitude (Vp-p) of nasal cycle measured by PVDF nasal sensors were analyzed for right nostril (RN) and left nostril (LN) in both the groups. Spearman’s rho correlation was calculated. The relationship between PVDF nasal sensor measurements and severity of nasal obstruction (VAS score) were assessed by ANOVA. In healthy group, the measurement of nasal airflow by PVDF nasal sensor for RN and LN were found to be 51.14 ± 5.87% and 48.85 ± 5.87%, respectively. In patient group, PVDF nasal sensor indicated lesser nasal airflow in the blocked nostrils (RN: 23.33 ± 10.54% and LN: 32.24 ± 11.54%). Moderate correlation was observed in healthy group (r = − 0.710, p < 0.001 for RN and r = − 0.651, p < 0.001 for LN), and moderate to strong correlation in patient group (r = − 0.751, p < 0.01 for RN and r = − 0.885, p < 0.0001 for LN). Conclusion PVDF nasal sensor method is a newly developed technique for measuring the nasal airflow. Moderate to strong correlation was observed between PVDF nasal sensor data and VAS scores for nasal obstruction. In our present study, PVDF nasal sensor technique successfully differentiated between healthy subjects and patients with nasal obstruction. Additionally, it can also assess severity of nasal obstruction in comparison with VAS. Thus, we propose that the PVDF nasal sensor technique could be used as a new diagnostic method to evaluate nasal obstruction in routine clinical practice.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The aim of this study is to validate the applicability of the PolyVinyliDene Fluoride (PVDF) nasal sensor to assess the nasal airflow, in healthy subjects and patients with nasal obstruction and to correlate the results with the score of Visual Analogue Scale (VAS). PVDF nasal sensor and VAS measurements were carried out in 50 subjects (25-healthy subjects and 25 patients). The VAS score of nasal obstruction and peak-to-peak amplitude (Vp-p) of nasal cycle measured by PVDF nasal sensors were analyzed for right nostril (RN) and left nostril (LN) in both the groups. Spearman’s rho correlation was calculated. The relationship between PVDF nasal sensor measurements and severity of nasal obstruction (VAS score) were assessed by ANOVA. In healthy group, the measurement of nasal airflow by PVDF nasal sensor for RN and LN were found to be 51.14 ± 5.87% and 48.85 ± 5.87%, respectively. In patient group, PVDF nasal sensor indicated lesser nasal airflow in the blocked nostrils (RN: 23.33 ± 10.54% and LN: 32.24 ± 11.54%). Moderate correlation was observed in healthy group (r = − 0.710, p < 0.001 for RN and r = − 0.651, p < 0.001 for LN), and moderate to strong correlation in patient group (r = − 0.751, p < 0.01 for RN and r = − 0.885, p < 0.0001 for LN). Conclusion PVDF nasal sensor method is a newly developed technique for measuring the nasal airflow. Moderate to strong correlation was observed between PVDF nasal sensor data and VAS scores for nasal obstruction. In our present study, PVDF nasal sensor technique successfully differentiated between healthy subjects and patients with nasal obstruction. Additionally, it can also assess severity of nasal obstruction in comparison with VAS. Thus, we propose that the PVDF nasal sensor technique could be used as a new diagnostic method to evaluate nasal obstruction in routine clinical practice. |
2. | Manjunatha, Roopa G; Rajanna, K; Mahapatra, Roy D; Prakash, Surya Evaluation of polyvinylidene fluoride nasal sensor to assess deviated nasal septum in comparision with peak nasal inspiratory flow measurements Journal Article American Journal of Rhinology & Allergy, 28 (1), pp. 62-67, 2014. @article{Manjunatha2014, title = {Evaluation of polyvinylidene fluoride nasal sensor to assess deviated nasal septum in comparision with peak nasal inspiratory flow measurements}, author = {G. Roopa Manjunatha and K. Rajanna and D. Roy Mahapatra and Surya Prakash}, url = {http://www.ingentaconnect.com/content/ocean/ajra/2014/00000028/00000001/art00022}, doi = {10.2500/ajra.2014.28.3996}, year = {2014}, date = {2014-01-01}, journal = {American Journal of Rhinology & Allergy}, volume = {28}, number = {1}, pages = {62-67}, abstract = {Deviated nasal septum (DNS) is one of the major causes of nasal obstruction. Polyvinylidene fluoride (PVDF) nasal sensor is the new technique developed to assess the nasal obstruction caused by DNS. This study evaluates the PVDF nasal sensor measurements in comparison with PEAK nasal inspiratory flow (PNIF) measurements and visual analog scale (VAS) of nasal obstruction. Methods: Because of piezoelectric property, two PVDF nasal sensors provide output voltage signals corresponding to the right and left nostril when they are subjected to nasal airflow. The peak-to-peak amplitude of the voltage signal corresponding to nasal airflow was analyzed to assess the nasal obstruction. PVDF nasal sensor and PNIF were performed on 30 healthy subjects and 30 DNS patients. Receiver operating characteristic was used to analyze the DNS of these two methods. Results: Measurements of PVDF nasal sensor strongly correlated with findings of PNIF (r = 0.67; p < 0.01) in DNS patients. A significant difference (p < 0.001) was observed between PVDF nasal sensor measurements and PNIF measurements of the DNS and the control group. A cutoff between normal and pathological of 0.51 Vp-p for PVDF nasal sensor and 120 L/min for PNIF was calculated. No significant difference in terms of sensitivity of PVDF nasal sensor and PNIF (89.7% versus 82.6%) and specificity (80.5% versus 78.8%) was calculated. Conclusion: The result shows that PVDF measurements closely agree with PNIF findings. Developed PVDF nasal sensor is an objective method that is simple, inexpensive, fast, and portable for determining DNS in clinical practice.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Deviated nasal septum (DNS) is one of the major causes of nasal obstruction. Polyvinylidene fluoride (PVDF) nasal sensor is the new technique developed to assess the nasal obstruction caused by DNS. This study evaluates the PVDF nasal sensor measurements in comparison with PEAK nasal inspiratory flow (PNIF) measurements and visual analog scale (VAS) of nasal obstruction. Methods: Because of piezoelectric property, two PVDF nasal sensors provide output voltage signals corresponding to the right and left nostril when they are subjected to nasal airflow. The peak-to-peak amplitude of the voltage signal corresponding to nasal airflow was analyzed to assess the nasal obstruction. PVDF nasal sensor and PNIF were performed on 30 healthy subjects and 30 DNS patients. Receiver operating characteristic was used to analyze the DNS of these two methods. Results: Measurements of PVDF nasal sensor strongly correlated with findings of PNIF (r = 0.67; p < 0.01) in DNS patients. A significant difference (p < 0.001) was observed between PVDF nasal sensor measurements and PNIF measurements of the DNS and the control group. A cutoff between normal and pathological of 0.51 Vp-p for PVDF nasal sensor and 120 L/min for PNIF was calculated. No significant difference in terms of sensitivity of PVDF nasal sensor and PNIF (89.7% versus 82.6%) and specificity (80.5% versus 78.8%) was calculated. Conclusion: The result shows that PVDF measurements closely agree with PNIF findings. Developed PVDF nasal sensor is an objective method that is simple, inexpensive, fast, and portable for determining DNS in clinical practice. |
3. | Manjunatha, Roopa G; Rajanna, K; Mahapatra, Roy D; Nayak, M M Differentiability between normal and respiratory tract disorder respiration pattern using smart sensor Presentation 07.09.2013. @misc{Manjunatha2013, title = {Differentiability between normal and respiratory tract disorder respiration pattern using smart sensor}, author = {G. Roopa Manjunatha and K. Rajanna and D. Roy Mahapatra and M. M. Nayak}, year = {2013}, date = {2013-09-07}, booktitle = {Proceedings of the 6th ISSS National Conference on MEMS, Smart Materials, Structures and Systems, India}, pages = {126-129}, keywords = {}, pubstate = {published}, tppubtype = {presentation} } |
4. | Manjunatha, Roopa G; Ranjith, N; Meghashree, Y V; Rajanna, K; Mahapatra, Roy D Identification of different respiratory rate by a piezo polymer based nasal sensor Conference Proceedings of the 2013 IEEE Sensors Conference, 03.-6.11.13, Baltimore (USA), 2013. @conference{Manjunatha2013b, title = {Identification of different respiratory rate by a piezo polymer based nasal sensor}, author = {G. Roopa Manjunatha and N. Ranjith and Y. V. Meghashree and K. Rajanna and D. Roy Mahapatra}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/06688479.pdf}, doi = {10.1109/ICSENS.2013.6688479}, year = {2013}, date = {2013-12-19}, booktitle = {Proceedings of the 2013 IEEE Sensors Conference, 03.-6.11.13, Baltimore (USA)}, pages = {1398-1401}, abstract = {In this paper, we present a new nasal sensor system developed using Polyvinylidene fluoride (PVDF) piezo polymer in cantilever configuration and its applicability for measuring human Respiration Rate (RR). Two identical PVDF nasal sensors are mounted on a headphone such that they are located below Right Nostril (RN) and Left Nostril (LN), in such a way that the nasal airflow during inspiration and expiration impinge on sensors. Due to nasal airflow, piezoelectric natured PVDF nasal sensors generate corresponding voltage signals. The RR is the number of breaths per minute (bpm). The RR was determined from the filtered respiratory signals, by computing a power spectral density (PSD) spectrum using Welch method of averaged periodograms. The developed PVDF nasal sensors were capable of identifying different RR corresponding to normal (18.5±1.5 bpm), tachypnea (34.5±4 bpm), and bradypnea (10.5±2.2 bpm) similar to ‘Gold standard’ Respiratory Inductance Plethysmograph (RIP) method and Nasal Prongs (NP).}, keywords = {}, pubstate = {published}, tppubtype = {conference} } In this paper, we present a new nasal sensor system developed using Polyvinylidene fluoride (PVDF) piezo polymer in cantilever configuration and its applicability for measuring human Respiration Rate (RR). Two identical PVDF nasal sensors are mounted on a headphone such that they are located below Right Nostril (RN) and Left Nostril (LN), in such a way that the nasal airflow during inspiration and expiration impinge on sensors. Due to nasal airflow, piezoelectric natured PVDF nasal sensors generate corresponding voltage signals. The RR is the number of breaths per minute (bpm). The RR was determined from the filtered respiratory signals, by computing a power spectral density (PSD) spectrum using Welch method of averaged periodograms. The developed PVDF nasal sensors were capable of identifying different RR corresponding to normal (18.5±1.5 bpm), tachypnea (34.5±4 bpm), and bradypnea (10.5±2.2 bpm) similar to ‘Gold standard’ Respiratory Inductance Plethysmograph (RIP) method and Nasal Prongs (NP). |
5. | Manjunatha, Roopa G; Rajanna, K; Mahapatra, Roy D; Dorasala, Srinivas Piezoelectric sensing: Evaluation for clinical investigation of deviated nasal septum Journal Article Allergy & Rhinology, 4 (3), pp. 140-150, 2013. @article{Manjunatha2013b, title = {Piezoelectric sensing: Evaluation for clinical investigation of deviated nasal septum}, author = {G. Roopa Manjunatha and K. Rajanna and D. Roy Mahapatra and Srinivas Dorasala}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/s5.pdf}, doi = {10.2500/ar.2013.4.0066}, year = {2013}, date = {2013-10-31}, journal = {Allergy & Rhinology}, volume = {4}, number = {3}, pages = {140-150}, abstract = {Noninvasive objective evaluation of nasal airflow is one of the important clinical aspects. The developed polyvinylidene fluoride (PVDF) sensor enables measurement of airflow through each side of the nose using its piezoelectric property. This study was designed to evaluate the diagnostic capability of the PVDF sensor in assessing the deviated nasal septum (DNS). PVDF nasal sensor uses its piezoelectric property to measure the peak-to-peak amplitude (Vp-p) of nasal airflow in both of the nostrils: right nostril (RN) and left nostril (LN), separately and simultaneously. We have compared the results of PVDF nasal sensor, visual analog scale (VAS), and clinician scale for 34 DNS patients and 28 healthy controls. Additionally, the results were further analyzed by receiver operating characteristic curve and correlation between PVDF nasal sensor and VAS in detecting DNS. We found a significant difference in the peak-to-peak amplitude values of the test group and the control group. The correlation between the PVDF nasal sensor measurements and VAS (RN and LN combined) for test group was statistically significant (−0.807; p < 0.001). Sensitivity and specificity of the PVDF nasal sensor measurements in the detection of DNS (RN and LN combined) was 85.3 and 74.4%, respectively, with optimum cutoff value ≤0.34 Vp-p. The developed PVDF nasal sensor is noninvasive and requires less patient efforts. The sensitivity and specificity of the PVDF nasal sensor are reliable. According to our findings, we propose that the said PVDF nasal sensor can be used as a new diagnostic tool to evaluate the DNS in routine clinical practice.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Noninvasive objective evaluation of nasal airflow is one of the important clinical aspects. The developed polyvinylidene fluoride (PVDF) sensor enables measurement of airflow through each side of the nose using its piezoelectric property. This study was designed to evaluate the diagnostic capability of the PVDF sensor in assessing the deviated nasal septum (DNS). PVDF nasal sensor uses its piezoelectric property to measure the peak-to-peak amplitude (Vp-p) of nasal airflow in both of the nostrils: right nostril (RN) and left nostril (LN), separately and simultaneously. We have compared the results of PVDF nasal sensor, visual analog scale (VAS), and clinician scale for 34 DNS patients and 28 healthy controls. Additionally, the results were further analyzed by receiver operating characteristic curve and correlation between PVDF nasal sensor and VAS in detecting DNS. We found a significant difference in the peak-to-peak amplitude values of the test group and the control group. The correlation between the PVDF nasal sensor measurements and VAS (RN and LN combined) for test group was statistically significant (−0.807; p < 0.001). Sensitivity and specificity of the PVDF nasal sensor measurements in the detection of DNS (RN and LN combined) was 85.3 and 74.4%, respectively, with optimum cutoff value ≤0.34 Vp-p. The developed PVDF nasal sensor is noninvasive and requires less patient efforts. The sensitivity and specificity of the PVDF nasal sensor are reliable. According to our findings, we propose that the said PVDF nasal sensor can be used as a new diagnostic tool to evaluate the DNS in routine clinical practice. |
- Indoor positioning and navigation of motorized objects
Principal Investigator: K. V. S. Hari (Department of Electrical Communication Engineering)
Unmanned motorized vehicles are used in hazardous situations for disaster management. These situations can be anything ranging from fire, earthquakes, to other types of calamities (nuclear/chemical) where initially humans cannot be involved directly. This project aimed to develop an inertial navigation system (INS) for four vehicles moving in an indoor environment, in order to track their position indoors and also control them accordingly from outside. This is possible through the use of an inertial measure unit (IMU), which provides the position and a camera provides the visual and these are transmitted over the WiFi to the command station.
To go about building this, (1) a blueprint of the hardware system required for the four vehicles was prepared. This included identifying the hardware components for the system; such as the IMU, microcontrollers, wireless devices, battery packs and devices to provide visualization. With this in hand, (2) a prototype of the system was developed. The navigation algorithms are written in Matlab and C++, for porting onto the embedded system, which in our case is the BeagleBoard. The network modules for the communication between the vehicle and command station are setup using Wi-Fi. Also, a webcam is installed on the vehicle to provide visualization support. Having the system ready, (3) it was tested by collecting data and analysing the positioning details. The stop-and-go motion, on which the vehicle was designed to move, warranted a better threshold in order to get accurate distance and trajectory. This led to further modifications in the algorithm, to suit the system better. The video streaming was also tested simultaneously and found to be functioning as required.
Apart from this, the battery pack was improved upon, for superior functioning and compactness. The range of the WiFi was tested with different dongles. The vehicle was tracked and the trajectory the path taken was plotted, too.
- Jewellery embedded with sensors and bluetooth chips and interfaced to a mobile phone and/or computers
Principal Investigator: G. K. Ananthasuresh (Department of Mechanical Engineering)
The project aimed to create a cognitive ring that – using hand-gestures – can interface with a smart phone, a computer and physical devices. The main task was to design, fabricate, and integrate a three-axis accelerometer, Bluetooth chip, and micro-controller chip into the small form-factor of the ring. Writing the necessary code was also part of the project.
Based on the literature survey and market studies done, currently the available devices which employ similar technologies are pedometers, wrist watches and other health parameters measuring devices. For gesture recognition wrist watches and inertial sensor based devices used in game consoles are available. Most of the game console controllers depend on line of sight, and a purely sensor driven game controller which does not rely on line of sight is not still available.
Patent Application
Saxena, Dhruv; Mehrota, Pragati; Rao Hiteshwar; Ananthasuresh, G. K.: A method for recognizing gestures using an accelerometer mounted onto a wearable device, Indian Patent Application No. 5699/CHE/2013 (24.06.16)
- Touch screen anywhere
Principal Investigator: Bharadwaj Amrutur (Robert Bosch Centre for Cyber-Physical Systems)
We explored two threads for this activity. One was based on Microsoft’s Kinect platform to extract depth information, and the other was to use a standard camera for doing the same. In the Kinect approach, the Kinect system provides the depth information for any object placed in front of it. Thus the depth info for the fingers are obtained and then thresholded to determine if they have touched the surface. Kinect relies on a infrared structured light pattern projection, coupled with an IR camera to image the pattern. The pattern’s distortions are then analysed to extract the depth map.
In the second approach, we used a standard camera to image a structured light pattern modulation of the projected image. This enabled us to use any camera for such application. Furthermore, the modulation region is restricted to the places near the finger tips to minimize image quality degradation.
- Ultralow detection of ammonia using nanoparticles based chemiresistor sensors
Principal Investigator: Karuna Kar Nanda (Materials Research Centre)
Undetected ammonia might lead to severe burns on skin, eyes, throat, or lungs causing permanent blindness, lung disease, kidney and liver malfunction, diabetes, asthma, cancer, and ulcers. Sensors based on optical, electrical, and chemical detection have attracted significant attention. It is desirable to detect few ppb (parts-per-billion) level or below for useful medical applications and environmental monitoring. Efforts are being made to detect ammonia concentration in wide range starting from ppb to ppm (parts-per-million) level and especially, at room temperature.
We synthesize Au nanoparticles by one-step green synthesis method using polysaccharide (Guar Gum, GG) as the reducing as well as capping agents. First, we demonstrated GG/AuNPs nanocomposite (GG/AuNPs NC) for detection of aqueous ammonia based on surface plasmon resonance (SPR). It has good reproducibility, response times of 10 s and excellent sensitivity with a detection limit of 1 pp. We also followed the chemiresitive method based on the change in the current with ammonia concentration. Here, we have reported for the first time an ultrasensitive gold nanoparticles based room temperature sensor that can detect ammonia level in urine and quantify the urea level in it. The sensor can detect sub parts-per-quadrillion (ppq) of ammonia which is the lowest ever achieved at room temperature. Sensitivity, stability, reproducibility and durability studies revealed excellent device properties that can be explored as ammonia sensor for environmental and medical applications.
Project Publications
1. | Pandey, Sandanand; Nanda, Karuna K Au nanocomposite based chemiresistive Ammonia sensor for health monitoring Journal Article ACS Sensors, 1 (1), pp. 55-62, 2016. @article{Pandey2016, title = {Au nanocomposite based chemiresistive Ammonia sensor for health monitoring}, author = {Sandanand Pandey and Karuna K. Nanda}, url = {http://www.rbccps.org/wp-content/uploads/2018/12/acssensors.5b00013.pdf}, doi = {10.1021/acssensors.5b00013}, year = {2016}, date = {2016-01-29}, journal = {ACS Sensors}, volume = {1}, number = {1}, pages = {55-62}, abstract = {We have developed a fast and highly sensitive chemiresistive sensor based on the nanocomposite of polysaccharide (guar gum) and gold nanoparticles for the room temperature detection of ammonia in the range of 0.1 parts-per-quadrillion (ppq) to 75 000 parts-per-million (ppm). Sensor response, selectivity, and stability studies reveal excellent sensing of the nanocomposite. The room temperature operation under ambient conditions and the wide range sensing indicates that the composites can be explored for environmental as well as biomedical applications. We have for the first time quantified the ammonia level released from the urine and blood serum of human beings using the resisitive sensor. The urine ammonia level was found to be ∼24 000 ppm and is higher for patients with renal problems. This demonstrated the utility of the sensor for health monitoring.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We have developed a fast and highly sensitive chemiresistive sensor based on the nanocomposite of polysaccharide (guar gum) and gold nanoparticles for the room temperature detection of ammonia in the range of 0.1 parts-per-quadrillion (ppq) to 75 000 parts-per-million (ppm). Sensor response, selectivity, and stability studies reveal excellent sensing of the nanocomposite. The room temperature operation under ambient conditions and the wide range sensing indicates that the composites can be explored for environmental as well as biomedical applications. We have for the first time quantified the ammonia level released from the urine and blood serum of human beings using the resisitive sensor. The urine ammonia level was found to be ∼24 000 ppm and is higher for patients with renal problems. This demonstrated the utility of the sensor for health monitoring. |
2. | Pandey, Sadanand; Goswami, Gopal K; Nanda, Karuna K Green synthesis of polysaccharide/gold nanoparticle nanocomposite: An efficient ammonia sensor Journal Article Carbohydrate Polymers, 94 (1), pp. 229-234, 2013. @article{Pandey2013, title = {Green synthesis of polysaccharide/gold nanoparticle nanocomposite: An efficient ammonia sensor}, author = {Sadanand Pandey and Gopal K. Goswami and Karuna K. Nanda}, url = {http://www.rbccps.org/wp-content/uploads/2017/10/1-s2.0-S0144861713000131-main.pdf}, doi = {10.1016/j.carbpol.2013.01.009}, year = {2013}, date = {2013-04-15}, journal = {Carbohydrate Polymers}, volume = {94}, number = {1}, pages = {229-234}, abstract = {A low cost eco-friendly method for the synthesis of gold nanoparticles (AuNPs) using guar gum (GG) as a reducing agent is reported. The nanoparticles obtained are characterized by UV–vis spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). Based on these results, a potential mechanism for this method of AuNPs synthesis is discussed. GG/AuNPs nanocomposite (GG/AuNPs NC) was exploited for optical sensor for detection of aqueous ammonia based on surface plasmon resonance (SPR). It was found to have good reproducibility, response times of ∼10 s and excellent sensitivity with a detection limit of 1 ppb (parts-per-billion). This system allows the rapid production of an ultra-low-cost GG/AuNPs NC-based aqueous ammonia sensor.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A low cost eco-friendly method for the synthesis of gold nanoparticles (AuNPs) using guar gum (GG) as a reducing agent is reported. The nanoparticles obtained are characterized by UV–vis spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). Based on these results, a potential mechanism for this method of AuNPs synthesis is discussed. GG/AuNPs nanocomposite (GG/AuNPs NC) was exploited for optical sensor for detection of aqueous ammonia based on surface plasmon resonance (SPR). It was found to have good reproducibility, response times of ∼10 s and excellent sensitivity with a detection limit of 1 ppb (parts-per-billion). This system allows the rapid production of an ultra-low-cost GG/AuNPs NC-based aqueous ammonia sensor. |
- Wireless force and torque sensors for applications in complex fluids and biomechanics
Principal Investigator: Prabhu R. Nott (Department of Chemical Engineering)
Granular flows occur widely in industrial processes (processing of food grains, mineral ores, pharmaceutical powders) and in natural phenomena (avalanches, mud slides), yet their mechanics is poorly understood. A major factor hampering the control of processes involving granular flow, such as filling detergent sachets or dosing a drug capsule, is the poor quality of instrumentation available for these systems when compared to fluids.
In our laboratory, we expanded our understanding of the kinematics and rheology of such materials by making careful measurements in simple flows of model granular materials, experiments and using them to refine continuum theories. We find the need for measuring the stress on a rotating cylinder that is immersed in a granular material. This requires the signals to be transmitted wirelessly from the sensor. Wireless transceivers are commercially available from many sources, but are proved unsuitable for our purpose as we required wireless transmission of voltage signals that can vary over a wide range. The innovation in this product therefore is in building a custom-made, small, low-cost, and accurate sensor-cum-transceiver unit, that adapts to the strength of the signal. Another useful consequence of this project was the development of a sensor for granular materials that may be used for flow control.