Browsing by Author "Kumar, V."

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2019-nCoV disease control and rehabilitation: Insights from twitter analytics
(Institute of Electrical and Electronics Engineers Inc., 2020) Chetty, N.; Alathur, S.; Kumar, V.
Coronaviruses are the large family of viruses and life threatening with the capabilities to cause respiratory related diseases. The current outbreak of 2019-nCoV (novel Coronavirus) is challenging governance authorities and health care systems around the globe. The epidemic of 2019-nCoV is affecting people globally. The purpose of this paper is to examine the current status of disease control and rehabilitation in relation to outbreak of 2019-nCoV. In this regard, the Twitter social media contents are collected, analyzed and interpreted. Using a set of appropriate keywords, 110000 tweets are extracted from Twitter social media. The collected tweets are first pre-processed and then analyzed with a software developed in R language. The discussions on social media in relation to the outbreak of 2019-nCoV involves disease control, rehabilitation and anti-rehabilitation. Expressions involving specific locations revealed that the discussions are more oriented towards antirehabilitation than rehabilitation and disease control. The content analysis also revealed that the outbreak epidemic victimizes those who possess weaker immune system. Â© 2020 IEEE.
A 0.15 μm GaN HEMT device to circuit approach towards dual-band ultra-low noise amplifier using defected ground bias technique
(Elsevier GmbH, 2023) Gupta, M.P.; Kumar, S.; Elizabeth Caroline, B.; Song, H.; Kumar, V.; Gorre, P.
This work presents a GaN HEMT device to circuit approach towards low noise amplifier (LNA) using defective ground bias (DGB) technique. This is the first MMIC GaN HEMT LNA design to offer dual-band of operation in both L and S-bands to the author's best knowledge. The proposed 0.15-μm GaN HEMT device fabrication achieves a high output power of 20 W using slot radiation phenomenon. The proposed DGB technique consists of gate and drain biasing topologies which achieves a dual-band of operation using microwave approach. The DGB technique is incorporated into GaN HEMT LNA which achieves high input and output power with good stability. To achieve an optimal noise, high I/O power, and almost flat gain at both L and S-bands, the defective ground structure of bias topologies is modeled and optimized. An artificial ground defect is created to offer resonant properties for the DGS of a microstrip line, which utilizes frequency-selective properties to improve the performance of the LNA circuit by suppressing the harmonics and scaling the size. The dedicated LNA shows the benefits of compact size, extremely low noise figure of 0.74/1.6 dB, high output power of 44 dBm and nearly flat gain of 14/11 dB at 1.17/2.49 GHz with the unique methodologies suggested. The compact GaN HEMT LNA could overcome the weak signal strength received by RF receiver for smart rail transport system. © 2023 Elsevier GmbH
Advances of membrane technology in wastewater treatment
(Elsevier, 2024) Deepthi, P.V.; Viji, K.; Vijesh, A.M.; Isloor, A.M.; Kumar, V.
Pure water scarcity is becoming a real threat to the modern world. Rapid growth in the textile, paper, and printing industries has caused the production of large quantities of dye effluents, and they must be treated before passing to the water bodies or lands to minimize pollution and environmental impacts. Polymeric membrane-based filtration has been established as an optimal and greener approach for removing hazardous dyes from polluted water. Superior thermal, chemical, and mechanical properties and convenient modifiability made polysulfone (PSF), polyethersulfone (PES), and polyphenylsulfone (PPSU) ideal for the production of membranes for the treatment of dye effluents from industries. This chapter emphasizes the recent developments in modified PSF, PES, and PPSU membranes and their dye rejection properties. © 2025 Elsevier Inc. All rights reserved.
An Integrated Onboard EV Charger With Wide Voltage Range Compatibility
(Institute of Electrical and Electronics Engineers Inc., 2025) Kumar, V.; Prabhakaran, P.; Reddy, B.D.; Febin, J.L.F.
Electric vehicles (EVs) typically employ separate onboard chargers and traction inverters for battery charging and motor operation, respectively. This paper proposes a bidirectional integrated onboard charger (BIOC) that utilizes a single power converter to perform both functions, thereby reducing cost, improving system compactness, and supporting fast charging. The proposed BIOC architecture is implemented using a totem-pole power factor correction (PFC) stage combined with an additional coupling unit. This configuration supports a wide range of battery voltages and is compatible with both AC and DC grid inputs. The BIOC incorporates active power decoupling (APD) to minimize voltage ripple at the battery terminals during high-voltage (HV) battery charging. Leakage current analysis of the totem-pole PFC stage confirms compliance with safety standards, and a detailed switch loss calculation procedure is presented. A comprehensive controller design is developed using State-Space Averaging (SSA) and Small Signal Modelling (SSM), followed by a K-factor method to ensure optimal performance across various operating modes. The proposed system is validated through simulations on a 2 kW Simulink model and experimental testing on a 400 W scaled-down prototype, demonstrating effective charging of an EV battery across a wide voltage range from both AC and DC grids. This work offers a unified, efficient, and cost-effective solution for integrated onboard EV charging. © 2013 IEEE.
Application of ISM technique for analysis of the procurement related attributes in JIT supply chain management
(Inderscience Publishers, 2014) Mishra, O.P.; Kumar, V.; Garg, D.
The fierce competition in selling a product has made us have to think differently. The supply chain is one issue in front of each production firm to compete with another and to get privilege of another. The excellence of the supply chain is possible only when the product is of the best quality while being cost competitive. The reduction of the production cost has become the focus point in reducing the overall cost of the supply chain. This paper focuses JIT procurement process in the SC to cut one the overall costs. To estimate the factors affecting the JIT procurement (JP) we have recognised the important attributes from the literatures. A questionnaire-based survey was carried out to give the ranking of the attributes found from literature and then an interpretative structural model (ISM) is prepared to link the levels of importance of the JP attributes among themselves. On the basis of levels of the attributes managerial staff are suggested to focus on the particular issues to make the JP successful, therefore making the JIT supply chain management successful even in the worst scenario. Copyright © 2014 Inderscience Enterprises Ltd.
Artificial Intelligence-Based Model forÂ Detecting Inappropriate Content onÂ theÂ Fly
(Springer Science and Business Media Deutschland GmbH, 2023) Ranjan, A.; Pintu; Kumar, V.; Singh, M.P.
Social media made it convenient for users to express, communicate, discuss, and exchange their opinions on various issues in recent years. For example, Twitter, YouTube, Facebook, and News portals allow users to express themselves through comments. However, such platforms are being misused in the name of freedom of speech. Numerous improper messages towards specific persons or communities can be found in them that use abusive, vulgar, hostile, or harsh words. Moreover, bots are also involved in exchanging such messages nowadays. As a result, user experiences are sometimes ruined on social media. Therefore, automatic identification and filtering of such offensive messages is a significant issue for improving user experience. This paper proposes a heterogeneous ensemble-based machine learning (ML) model powered by artificial intelligence (AI) that can classify messages into Threat, Obscenity, Insult, Identity Hate, Toxic, and Severe Toxic categories. The experimental evaluation of the proposed model on a standard dataset demonstrates the accuracy and adaptability of the proposed model. Â© 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
Automatic Optic Disc segmentation using maximum intensity variation
(2013) Kumar, V.; Sinha, N.
Optic disc (OD) segmentation is an important step in automating eye screening for pathological conditions. In this paper, we propose an intensity-based approach to detect the OD boundary, given OD center. OD center is utilized to crop the sub-image that encloses the OD, within which candidate contour points are obtained. Points of maximum intensity variation, both horizontally and vertically, are chosen as candidate contour points. Iterative curve fitting is carried out, incorporating smoothness constraints. The area within the contour is checked for values of mean intensity, variance and compactness. The algorithm is applied on 152 images taken from two public datasets, DIARETDB1 and MESSIDOR. The validation criteria used are common area overlapping between automated segmentation and true OD region (score), sensitivity and Mean Distance to Closest Point (MDCP). The algorithm renders, on an average, a score value of 90%, sensitivity of 93% and MDCP of 8.3 pixels. � 2013 IEEE.
Automatic Optic Disc segmentation using maximum intensity variation
(2013) Kumar, V.; Sinha, N.
Optic disc (OD) segmentation is an important step in automating eye screening for pathological conditions. In this paper, we propose an intensity-based approach to detect the OD boundary, given OD center. OD center is utilized to crop the sub-image that encloses the OD, within which candidate contour points are obtained. Points of maximum intensity variation, both horizontally and vertically, are chosen as candidate contour points. Iterative curve fitting is carried out, incorporating smoothness constraints. The area within the contour is checked for values of mean intensity, variance and compactness. The algorithm is applied on 152 images taken from two public datasets, DIARETDB1 and MESSIDOR. The validation criteria used are common area overlapping between automated segmentation and true OD region (score), sensitivity and Mean Distance to Closest Point (MDCP). The algorithm renders, on an average, a score value of 90%, sensitivity of 93% and MDCP of 8.3 pixels. Â© 2013 IEEE.
Child online safety in indian context
(Institute of Electrical and Electronics Engineers Inc., 2020) Andrews, D.; Alathur, S.; Chetty, N.; Kumar, V.
Children initiates the usage of Internet during young age and spend more time online. Apart from the benefits like improved education, entertainment, news and gaming, Internet poses severe threats to the children online. Ensuring online safety is a global challenge. The purpose of this paper is to examine online social media responses and awareness posts on children online safety. In this relation, Twitter social media responses after freeing the accusers of children sexual harassment and Facebook pages of some prominent personalities in India for online safety are analyzed. The results reveal that though the people are angry and fearful, they believe judiciary and police system and expecting safety from the same. The analysis of Facebook posts depicts that the concerned authorities are active towards child online safety and providing awareness through their representatives. People demand legal actions against the perpetrators of the crime to punish them. The necessary actions should be taken for cyber-crime awareness information to reach all social media users. Â© 2020 IEEE.
Compact Dual-Band Implantable Asymmetric Multi-Slot Patch Antenna for WMTS and ISM Applications
(Institute of Electrical and Electronics Engineers Inc., 2023) Bharadwaj, I.S.; Kumar, S.; Kumar, V.
A compact dual-band implantable multi-slot patch antenna for biotelemetry applications is proposed here. The proposed dual-band antenna operates at both WMTS frequency band of 1395-1400 MHz as well as the 5.8 GHz ISM band. The size of the dual band antenna is greatly reduced by inserting multi-slots into patch and ground plane in an asymmetric patterns. The proposed antenna occupies a compact size of 12 X 12 X 0.64 mm3. The antenna, which is fed by a microstrip feed line, achieves gains of -20.29 dBi and -8.52 dBi at dual-band of operation. The proposed antenna has the potential to be employed in different implantable biomedical devices for real-time monitoring of physiological data due to its small size and dual-band characteristics. Specific Absorption Rate (SAR) is also analysed to ensure human safety conditions. Â© 2023 IEEE.
Computational Analysis of Online Hate Content using Cognitive -AI
(Institute of Electrical and Electronics Engineers Inc., 2021) Chetty, N.; Alathur, S.; Andrews, D.; Kumar, V.
As the hate content is expressed based on the identity of an individual, it is influencing communal violence in society. The inappropriate content can be detected and analyzed using automated AI systems. The purpose of this paper is to study the role of AI systems in the detection of online hate content and how the cognitive processes affect the behavior of an individual. Therefore, using related keywords in the research domain, the published articles are searched through different search engines. The information from the associated articles and sources is reported in the paper. The literature review revealed that social media platforms could use AI systems to detect and analyze online hate content. It has been observed that the cognitive process affects both the perpetrators and the victims of online hate content. The paper also highlights some of the challenges in controlling online hate content. The paper concludes with a note that the hate content can be reduced by building robust AI systems and healthier cognitive processes of an individual. Â© 2021 IEEE.
Effect of Mechanical properties on Multi Axially Forged LM4 Aluminium Alloy
(Elsevier Ltd, 2020) Sajjan, S.S.; Kulkarni, M.V.; Ramesh, S.; Sharath, P.C.; Kumar, V.; Rajole, S.
Commercially available LM4 Aluminum alloy was subjected through Severe Plastic Deformation (SPD) method by Multi-Axial Forging Process (MAF) in ambient temperature. In this process, the material was processed successfully up to 5 Passes and mechanical properties such as tensile strength, compression strength and hardness of the as received and processed samples at ambient temperature were evaluated. The MAF processed sample result showed that the ultimate strength, percentage elongation and compression strength improved by 55 MPa, 3.75% and 162 MPa respectively as compared with the unprocessed sample. Hardness also increased with the increase in the number of passes. In the case of microstructure, grain size reduced from 110 Î¼m to 8 Î¼m after subjecting the sample to MAF. Fractography explains the nature of the fracture from received to processed samples by decreasing the size of the dimple and the type of fracture observed was ductile in nature. Improvement in strength and hardness of processed samples was observed due to the grain refinement and high amount of density dislocation in the material during MAF. Â© 2018 Elsevier Ltd.
Equilibrium and kinetic study for the removal of malachite green using activated carbon prepared from Borassus flabellofer male flower
(2010) JagadeeshBabu, P.E.; Kumar, V.; Visvanathan, R.
Activated carbon was prepared from dried Borassus flabellofer male flower and batch adsorption experiments were conducted to study its potential to remove malachite green (MG) dye. The process was further optimized by studying the operating variables like initial pH of the stock solution, activation temperature, initial dye concentration, adsorbent loading and contact time. The optimized pH and activation temperatures were found to be 7.55 and 450.C respectively, where further analysis was made using these optimal variables. Linear, Freundlich and Langmuir isotherms were studied and it was found that the Langmuir isotherms have the highest correlation coefficients compared to the others. Further, the sorption kinetics were analysed using pseudo-first-order and pseudo-second-order kinetic models. The data showed that the second-order equation was the more appropriate, which indicate that the intra-particle diffusion is the rate limiting factor. © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
Evaluating the PEM fuel cell performance under accelerated creep of sealants
(Elsevier Ltd, 2025) Kumar, V.; Koorata, P.K.
The physical properties of sealants could be crucial in affecting the performance and longevity of the polymer electrolyte membrane fuel cell (PEMFC). As the sealants' physical properties are temperature and stress-dependent due to their inherent viscoelasticity, their creep response must be explored. The numerical study presented in this article emphasizes evaluating the performance of low-temperature PEMFC (LT-PEMFC) influenced by polytetrafluoroethylene (PTFE) sealants' accelerated creep characterized by the compliance curves (MC-65). The performance of a 3D single-channel PEMFC model is investigated and compared for two cases, wherein the first case focused on PEMFC performance without sealant creep, and the second case incorporated sealants' accelerated creep to assess PEMFC performance. The detailed observation of reactant transport characteristics demonstrates that there is a substantial decline in oxygen reduction reaction (ORR) at the cathode gas diffusion layer (GDL) and cathode catalyst layer (CL) in the case of sealants' accelerated creep. Further, liquid saturation at the cathode GDL is observed to increase significantly, leading to a reduction in the performance of the cell. It is further conveyed that the current density for case 1 (without creep) and case 2 (sealants' accelerated creep) are 1.309655 and 1.041806 Acm?2, respectively, at a cell voltage of 0.4 V. The present study, therefore, addresses the viable interaction between fuel cell performance and the sealants’ accelerated creep characteristics. © 2025 Hydrogen Energy Publications LLC
Experimental and theoretical studies of various solar control window glasses for the reduction of cooling and heating loads in buildings across different climatic regions
(Elsevier Ltd, 2018) G, K.K.; Saboor, S.; Kumar, V.; Kim, K.-H.; Babu, A.
The glass material and position/orientation of windows are very important to control the heat gain in buildings. In this article, we studied the effect of different window glazing materials (such as bronze, green, grey, bronze-reflective, green-reflective, grey-reflective, gold-reflective, opal blue-reflective, and sapphire blue-reflective glass) in controlling the heat gain by the buildings. The spectral data of diverse window glasses have thus been measured in solar spectrum range of 300–2500 nm. Moreover, the MATLAB codes have been developed to compute solar optical properties (including transmittance, reflectance, and absorbance), solar heat gain coefficient (SHGC), and heat transfer through the glazing material. Thermal analysis was carried out using a total of nine window glasses in eight coordinal directions (E, W, N, S, SE, SW, NE, and NW) against three climatic conditions (hot and dry, warm and humid and composite) in India. In terms of net annual cooling and heating cost savings per window, the grey reflective glass was found to be the most energy saving glass among all glasses tested in this study. The grey reflective glass exhibited the highest cost saving in net annual cooling and heating in all eight orientations across three climatic regions. The grey reflective glass saved the net cost of heating and cooling by $ 61.24 per annum in the south orientation of Jodhpur climatic conditions. © 2018 Elsevier B.V.
Four-Phase Interleaved Bidirectional DC-DC Converter for Battery Energy Storage System
(Institute of Electrical and Electronics Engineers Inc., 2023) Kumar, V.; Nagendrappa, H.
This paper presents the operation of a DC-DC converter for bidirectional power transfer with battery energy storage system. The converter topology under study resolves the existing disadvantages of conventional buck - boost bidirectional converter and provides benefits in terms of reduced size with higher efficiency and lower input source ripple current. The performance of non-isolated 4-phase interleaved buck-boost bidirectional converter has been studied using MATLAB simulations. In order to get a better insight, this paper proposes a control method that takes the interaction of 4phase currents into account. In boost mode operation, battery is getting discharged while it maintains the DC bus voltage. In buck mode operation, battery is getting charged at constant current. The design of non-isolated four-phase interleaved bidirectional converter of 150 kW with simulation results are presented to validate the design and performance of the converter. Â© 2023 IEEE.
Handheld electrochemical workstation for serum albumin measurement
(2016) Hebbar, S.; Kumar, V.; Bhat, M.S.; Bhat, N.
This paper presents a novel handheld electrochemical workstation for serum albumin measurement. The system consists of a multi-path potentiostat module which performs electrochemical measurements on disposable test strip. The strip provides a port for applying blood sample. The test strip consists of 3 electrochemical cells for redundancy and parallel testing. The 3 sets of 3 electrodes (Working, Reference and Counter electrodes) are screen printed on a Polyethylene Terephthalate (PET) substrate. The system provides the unique capability of performing Cyclic Voltammetry and Chrono Amperometry measurements in three parallel paths. The system is very generic and flexible, with user defined inputs for voltage, sweep rate and time through 5 inch capacitive touch screen. The experimental results can be stored on micro SD card and the data is accessible with USB or Bluetooth interface. This paper reports an extensive characterization of system through several tests conducted on standard redox solution. The system is then validated for human serum albumin measurement, using clinical samples. This is the first ever point of care handheld diagnostic device in the world for human serum albumin measurement. � 2016 IEEE.
Handheld electrochemical workstation for serum albumin measurement
(Institute of Electrical and Electronics Engineers Inc., 2016) Hebbar, S.; Kumar, V.; Bhat, M.S.; Bhat, N.
This paper presents a novel handheld electrochemical workstation for serum albumin measurement. The system consists of a multi-path potentiostat module which performs electrochemical measurements on disposable test strip. The strip provides a port for applying blood sample. The test strip consists of 3 electrochemical cells for redundancy and parallel testing. The 3 sets of 3 electrodes (Working, Reference and Counter electrodes) are screen printed on a Polyethylene Terephthalate (PET) substrate. The system provides the unique capability of performing Cyclic Voltammetry and Chrono Amperometry measurements in three parallel paths. The system is very generic and flexible, with user defined inputs for voltage, sweep rate and time through 5 inch capacitive touch screen. The experimental results can be stored on micro SD card and the data is accessible with USB or Bluetooth interface. This paper reports an extensive characterization of system through several tests conducted on standard redox solution. The system is then validated for human serum albumin measurement, using clinical samples. This is the first ever point of care handheld diagnostic device in the world for human serum albumin measurement. Â© 2016 IEEE.
Hydrodynamic performance characteristics of semicircular breakwater—wave run-up and run-down
(2010) Hegde, A.V.; Ganesh, C.; Kumar, V.
Breakwaters are structures protecting a shore area, harbor, anchorage, or a basin from the fury of ocean waves. They create calm waters and give protection for safe mooring, operating and handling of ships, and provide protection to harbor facilities. Semicircular breakwaters are becoming increasingly popular these days, as they have high stability against the action of waves. The paper explains the physical model studies to evaluate the wave run-up (Rd/Hi) and wave run-down (Rd/Hi) on semicircular breakwater model for various incident wave heights H, wave periods T, water depths d and spacing (S) to diameter (D) ratios of perforations (S/D). It is found that relative wave run-up increases with the increase in wave steepness (Hi/gT2) and relative run-down decreases with the increase in wave steepness. Relative wave run-up and wave run-down values increase with the increase in depth parameter (d/gT2). The relative run-up and run-down values decrease with increasing perforations (decreasing S/D values) in breakwater. © 2010 Taylor & Francis Group, LLC.
Identification and characterization of novel indole based small molecules as anticancer agents through SIRT1 inhibition
(2013) Panathur, N.; Udayakumar, U.; Koushik, P.V.; Alvala, M.; Yogeeswari, P.; Sriram, D.; Kumar, V.
In our pursuit to develop new potential anticancer leads, we designed a combination of structural units of indole and substituted triazole; and a library of 1-{1-methyl-2-[4-phenyl-5-(propan-2-ylsulfanyl)-4H-1,2,4-triazol-3- yl]-1H-indol-3-yl}methanamine derivatives was synthesized and characterized. Cytotoxic evaluations of these molecules over a panel of three human cancer cell lines were carried out. Few molecules exhibited potent growth inhibitory action against the treated cancer cell lines at lower micro molar concentration. An in vitro assay investigation of these active compounds using recombinant human SIRT1 enzyme showed that one of the compounds (IT-14) inhibited the deacetylation activity of the enzyme. The in vivo study of IT-14 exemplified its promising action by reducing the prostate weight to the body weight ratio in prostate hyperplasia animal models. A remarkable decrease in the disruption of histoarchitecture of the prostate tissues isolated from IT-14 treated animal compared to that of the positive control was observed. The molecular interactions with SIRT1 enzyme were also supported by molecular docking simulations. Hence this compound can act as a lead molecule to treat prostatic hyperplasia. © 2013 Elsevier Masson SAS. All rights reserved.