Faculty Publications

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Publications by NITK Faculty

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Author: search.filters.author.Rawat, K.Has files: No

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    Anomaly Detection in Electric Powertrain System Software Behaviour
    (Institute of Electrical and Electronics Engineers Inc., 2023) Vyas, A.; Ghorpade, V.; Kamble, S.; Johnson, P.S.; Kamath, A.; Rawat, K.
    A software-in-loop (SIL) testing is a method of early testing of control software of a car in virtual environment. A system level testing is carried out on regular basis and it is important to see, if system is behaving as expected or unexpected. For unexpected behaviors, which test engineers not easily notice, modern techniques such as machine learning can give an advantage. This paper presents an application of machine learning algorithms that helps in identifying the abnormal patterns in time series data generated from electric powertrain system testing done in SIL environment for a Mercedes Benz Electric Car. Output of the SIL testing, results in time series data that is a collection of observations that are ordered chronologically and can be used to analyze trends, patterns, and changes over time. Anomaly detection in time series data is a process in machine learning that identifies data points, events, and observations that deviate from a dataset's normal behavior. By monitoring the expected and unexpected behavior of the electric powertrain system, anomaly detection can be a valuable tool for identifying potential issues. This study aims at coming up with an efficient process for anomaly detection in SIL. In order to get this process, various anomaly detection techniques are compared to detect a defined anomaly in time series data. Data pre-processing methods are also discussed before training the model. At the end, we conclude a best-fit method for identified anomaly. With finally identified method, a model was trained and used further in application. © 2023 IEEE.
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    Fluorescent MoS2 Quantum Dot-DNA Nanocomposite Hydrogels for Organic Light-Emitting Diodes
    (American Chemical Society service@acs.org, 2020) Pandey, P.K.; Ulla, H.; Satyanarayan, M.N.; Rawat, K.; Gaur, A.; Gawali, S.; Hassan, P.A.; Bohidar, H.B.
    In this study, we report the synthesis of water-soluble MoS2 quantum dots (MoS2, QD) by a hydrothermal one-step method. These QDs were mixed in an aqueous solution of 2 kbp DNA to form fluorescent nanocomposite hydrogels at a very low concentration of the nucleic acid (1.0% (w/v), normal gelation occurs at 2% (w/v)). The melting temperature Tmelt of these gels was 50 ± 2 °C while the hydrogels melt at 40 ± 2 °C, and the low-frequency storage modulus/gel strength G0 was 40 ± 2 Pa (9 ± 2 Pa for hydrogel). This clearly implied that MoS2 acted as a pseudo-cross-linker in the nanocomposite hydrogel formation. The remarkable synergy of interaction between DNA and QDs can be gauged from the fact that the gel strength and melting temperature increased with QD content regardless of the fact that both carried negative charge. Dynamic light scattering studies showed arrested dynamics at the onset of gelation, and the gel transition time or ergodicity breaking time ?EB decreased with the increase in QD concentration. Small-angle X-ray scattering data captured the internal structure of these gels. Thus, we have a unique nanocomposite DNA-based hydrogel that is fluorescent, and in 2-D, this soft matter remarkably exhibits the behavior of an organic light-emitting diode (OLED), which imparts sufficient novelty to this work. © © 2020 American Chemical Society.
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    Numerical modelling and analytical comparison of delamination during cryogenic drilling of cfrp
    (MDPI, 2021) Balan, A.S.S.; Kannan, C.; Jain, K.; Chakraborty, S.; Joshi, S.; Rawat, K.; F Alsanie, W.F.; Thakur, V.K.
    Carbon-Fibre-Reinforced Polymers (CFRPs) have seen a steady rise in modern industrial applications due to their high strength-to-weight ratio and corrosion resistance. However, their potential is being hindered by delamination which is induced on them during machining operations. This has led to the adoption of new and innovative techniques like cryogenic-assisted machining which could potentially help reduce delamination. This study is aimed at investigating the effect of cryogenic conditions on achieving better hole quality with reduced delamination. In this paper, the numerical analysis of the drilling of CFRP composites is presented. Drilling tests were performed experimentally for validation purposes. The effects of cooling conditions and their subsequent effect on the thrust force and delamination were evaluated using ABAQUS/CAE. The numerical models and experimental results both demonstrated a significant reduction in the delamination factor in CFRP under cryogenic drilling conditions. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.