Browsing by Author "Sastry, S."

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A comparison of different methods for determination of coupling factor and velocity response of coupled plates
(2013) Pankaj, A.C.; Sastry, S.; Murigendrappa, S.M.
Coupling loss factors (CLF) and velocity responses has been computed for two plates joined in a 'L' junction configuration using Statistical Energy Analysis. The analyses have been carried out to study the effects of internal loss/damping factor on the coupling factors. The effects of plate widths on the coupling factors and velocity responses at high frequencies has also been studied. The statistical energy parameters have been computed using analytical wave approach, finite element method and Free-SEA software. The studies have revealed that the coupling factor computed by the wave approach is independent of the internal loss factor as compared to the values computed using finite element method, wherein CLF increases linearly as the internal loss factor varies from a zero value, followed by a transition region and converges to the values obtained by the analytical wave approach and remains insensitive to changes at higher values of damping. The results obtained from the studies signify the effects of internal loss/damping factor and plate widths on proper selection and usage of the above mentioned methods for the estimation of coupling factors and velocity responses using statistical energy approach. © Vibroengineering.
CoCoA++: Delay gradient based congestion control for Internet of Things
(2019) Rathod, V.; Jeppu, N.; Sastry, S.; Singala, S.; Tahiliani, M.P.
In this paper, we propose a new congestion control algorithm called CoCoA++ to address the issue of network congestion in Internet of Things (IoT). Unlike the existing congestion control mechanisms that operate on instantaneous Round Trip Time (RTT) measurements in IoT, we use delay gradients to get a better measure of network congestion, and implement a probabilistic backoff to deal with congestion. We integrate the delay gradients and the probability backoff factor with Constrained Application Protocol (CoAP). The proposed algorithm is implemented and evaluated using the Cooja network simulator provided by Contiki OS. Subsequently, it is deployed and evaluated in a real testbed by using the FIT/IoT-LAB. We observe that delay gradients give a more accurate measure of congestion and the Retransmission Time Out (RTO) is reduced significantly, thereby leading to less delays and high packet sending rates. CoCoA++ being a minor improvement over the existing algorithm is easy to deploy. 2019 Elsevier B.V.
CoCoA++: Delay gradient based congestion control for Internet of Things
(Elsevier B.V., 2019) Rathod, V.; Jeppu, N.; Sastry, S.; Singala, S.; Tahiliani, M.P.
In this paper, we propose a new congestion control algorithm called CoCoA++ to address the issue of network congestion in Internet of Things (IoT). Unlike the existing congestion control mechanisms that operate on instantaneous Round Trip Time (RTT) measurements in IoT, we use delay gradients to get a better measure of network congestion, and implement a probabilistic backoff to deal with congestion. We integrate the delay gradients and the probability backoff factor with Constrained Application Protocol (CoAP). The proposed algorithm is implemented and evaluated using the Cooja network simulator provided by Contiki OS. Subsequently, it is deployed and evaluated in a real testbed by using the FIT/IoT-LAB. We observe that delay gradients give a more accurate measure of congestion and the Retransmission Time Out (RTO) is reduced significantly, thereby leading to less delays and high packet sending rates. CoCoA++ being a minor improvement over the existing algorithm is easy to deploy. © 2019 Elsevier B.V.
A comparison of different methods for determination of coupling factor and velocity response of coupled plates
(2013) Pankaj, A.C.; Sastry, S.; Murigendrappa, S.M.
Coupling loss factors (CLF) and velocity responses has been computed for two plates joined in a 'L' junction configuration using Statistical Energy Analysis. The analyses have been carried out to study the effects of internal loss/damping factor on the coupling factors. The effects of plate widths on the coupling factors and velocity responses at high frequencies has also been studied. The statistical energy parameters have been computed using analytical wave approach, finite element method and Free-SEA software. The studies have revealed that the coupling factor computed by the wave approach is independent of the internal loss factor as compared to the values computed using finite element method, wherein CLF increases linearly as the internal loss factor varies from a zero value, followed by a transition region and converges to the values obtained by the analytical wave approach and remains insensitive to changes at higher values of damping. The results obtained from the studies signify the effects of internal loss/damping factor and plate widths on proper selection and usage of the above mentioned methods for the estimation of coupling factors and velocity responses using statistical energy approach. Vibroengineering.
Modeling of Human Face Expressions and Hand Movement for Animation
(Institute of Electrical and Electronics Engineers Inc., 2018) Sangeetha, G.S.; Koolagudi, S.G.; Ramteke, P.B.; Singala, S.; Sastry, S.
Animation is the process of creating an illusion of motion by moving images rapidly in an order which minimally differ from each other. In this paper, a solution is proposed to simplify the process of animation by tracking movement of hand and facial expressions. Face detection performed using Haar-Cascade classifier whereas hand detection is achieved using Otsu's binarization and Ramer-Douglas-Peucker contour detection algorithm. Facial expression landmarks are captured from the Haarlike features. Hand movements feature points are extracted from the contour. Replay phase includes drawing the virtual object by calculating the translational factors and redrawing the virtual object in every frame during replay. The proposed approach is observed to achieve the smooth translation of face expression and hand movement and reduce the time and effort needed to make the animation. Copy Right Â© INDIACom-2018.