Agricultural automation: Mobile phone based analysis of images of plant leaves to give decision support in agriculture
Principal Investigator
Prof A. G. Ramakrishnan (Professor, Department of Computer Science and Automation)
Duration
16 August 2012 to 15 August 2015
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.
[sta_anchor id=”Cardiac”]Cardiac arrhythmias: In silico studies in realistic mathematical models for cardiac tissue
Principal Investigator
Prof Rahul Pandit (Chairman, Division of Physical and Mathematical Sciences and Professor, Department of Physics)
Duration
16 August 2012 to 15 August 2015
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. Abstract | BibTeX | Links:   @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. |
[sta_anchor id=”Computer”]Computer processing of wrist pulse signals acquired using fiber-optic techniques for healthcare appliances
Principal Investigator
Prof Talabattula Srinivas (Associate Professor, Department of Electrical Communication Engineering)
Duration
16 August 2012 to 15 August 2015
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.
[sta_anchor id=”Control”]Control and prevention of hospital acquired infections
Principal Investigator
Dr T. V. Prabhakar (Principal Research Scientist, Zero Energy Networks Laboratory)
Duration
12 May 2014 to 11 October 2015
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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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
[sta_anchor id=”Cyber”]Cyber surgery and remote patient care
Principal Investigator
Prof Ashitava Ghosal (Professor, Department of Mechanical Engineering)
Duration
16 August 2012 to 15 August 2015
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
26 entries « ‹ 1 of 3
› » | 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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. |
26 entries « ‹ 1 of 3
› » 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
[sta_anchor id=”Fiber”]Fiber Bragg Grating sensors for distributed bio-chemical sensing
Principal Investigator
Prof Manoj Varma (Associate Professor, Centre for Nano Science and Engineering)
Duration
16 August 2012 to 15 August 2015
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
30 entries « ‹ 1 of 3
› » | 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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. |
30 entries « ‹ 1 of 3
› » 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
[sta_anchor id=”Formal”]Formal analysis of CPS protocols and software
Principal Investigator
Prof Aditya Kanade (Associate Professor, Department of Computer Science and Automation)
Duration
16 August 2012 to 15 August 2015
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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. |
[sta_anchor id=”Low-cost”]Low-cost, optical detection of DNA for HPV detection in urine
Principal Investigator
Prof Manoj Varma (Associate Professor, Centre for Nano Science and Engineering)
Duration
1 February 2015 to 30 September 2015
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. Abstract | BibTeX | Links: @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%. |
[sta_anchor id=”Precision”]Precision farming model for peri-urban agriculture: Technological interventions and innovations to enhance the input use efficiency
Principal Investigator
Prof Jaywant H. Arakeri (Professor, Department of Mechanical Engineering)
Duration
16 August 2012 to 15 August 2015
The project is a 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 MDes project of Centre for Product Design and Manufacture (CPDM).
[sta_anchor id=”Remote”]Remote neonatal monitoring and intervention
Principal Investigator
Prof Bharadwaj Amrutur (Chairman, Robert Bosch Centre for Cyber-Physical Systems)
Duration
16 August 2012 to 15 August 2015
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. BibTeX @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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)
[sta_anchor id=”Sensor”]Sensor system for monitoring stroke patients in rehabilitation
Principal Investigator
Prof K. Gopinath (Professor, Department of Computer Science and Automation)
Duration
16 August 2012 to 15 August 2015
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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. |
[sta_anchor id=”Simulation”]Simulation environment with active feedback for epidural procedures
Principal Investigator
Prof M. S. Bobji (Assistant Professor, Department of Mechanical Engineering)
Duration
16 August 2012 to 15 August 2015
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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. |
[sta_anchor id=”Smart”]Smart transportation and mobility solutions
Principal Investigator
Prof T. G. Sitharam (Senior Professor, Department of Civil Engineering)
Duration
1 August 2013 to 31 July 2015
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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. |
[sta_anchor id=”SPMU”]SPMU based solar water pump and smart controller
Principal Investigator
Prof L. Umanand (Professor, Department of Electronic Systems Engineering)
Duration
1 May 2014 to 31 October 2015
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
[sta_anchor id=”Studies”]Studies into impact of dust and PV temperature on PV system (performance) efficiency in tropical regions
Principal Investigator
Prof Monto Mani (Associate Professor, Centre for Sustainable Technologies and Centre for Product Design and Manufacturing)
Duration
16 August 2012 to 15 August 2015
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. Abstract | BibTeX @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. BibTeX @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. BibTeX @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}
}
|
[sta_anchor id=”Verified”]Verified model of real–time operating systems for multi-core processors
Principal Investigator
Prof Deepak D’Souza (Associate Professor, Department of Computer Science and Automation)
Duration
16 August 2012 to 15 August 2015
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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. Abstract | BibTeX | Links: @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. |
[sta_anchor id=”Zero”]Zero energy smart building
Principal Investigator
Prof Joy Kuri (Professor, Department of Electronic System Engineering)
Duration
16 August 2012 to 15 August 2015
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. Abstract | BibTeX | Links: @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