Faculty Publications
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Item A semantic approach to text steganography in sanskrit using numerical encoding(Springer Verlag service@springer.de, 2019) Keshava, K.; Pravalika, A.; Abhishek, D.V.; Meghana, N.P.; Prasad, G.Steganography is the art of hiding a message within another so that the presence of the hidden message is indiscernible. People who are not intended to be the recipients of the message should not even suspect that a hidden message exists. Text steganography is challenging as it is difficult to hide data in text without affecting the semantics. Retention of the semantics in the generated stego-text is crucial to minimize suspicion.This paper proposes a technique for text steganography using classical language Sanskrit. As Sanskrit is morphologically rich with a very large vocabulary, it is possible to modify the cover text without affecting the semantics. In addition numerical encoding is used to map a Sanskrit character to a numerical value. This helps in hiding the message effectively. Moreover, in this technique, a key is used for additional security. The key is generated dynamically and is appended to the final message to further add security to the proposed method. The proposed method generated stego-texts with syntactic correctness of 96.7%, semantic correctness of 86.6%, and with a suspicion factor of just 23.4% upon evaluation. © Springer Nature Singapore Pte Ltd. 2019Item A parallel segmentation of brain tumor from magnetic resonance images(2012) Dessai, V.S.; Arakeri, M.P.; Guddeti, G.Medical image segmentation is nowadays at the core of medical image analysis and supports computer-aided diagnosis, surgical planning, intra-operative guidance or postoperative assessment. Large amounts of research efforts have been made in developing effective brain MR (magnetic resonance) image tumor segmentation methods in the past years. However algorithms proposed so far are time consuming because it involves lot of mathematical computations. Also serial segmentation of multiple MRI slices (usually required for 3D visualization) takes exponential time. This results in need for improvement in performance as far as the time complexity is concerned. This paper proposes a methodology that incorporates the K-means clustering and morphological operation for parallel segmentation of multiple MRI slices corresponding to single patient. Segmentation of multiple MRI slices for tumor extraction plays major role in 3D (Three Dimensional) visualization and serves as an input for the same. The proposed framework follows SIMD (Single Instruction Multiple Data) model and since the segmentation of individual slice is independent of each other and can be performed in parallel and multithreading definitely speeds up the entire process. Also the framework does not involve any kind of inter-process communication thus the time is saved here as well. © 2012 IEEE.Item Effect of nickel sulphate to hypophosphite ratio on the electroless deposition of Ni-P coatings on aluminium(Trans Tech Publications, 2014) Jayalakshmi, M.; Bhat, K.U.Electroless Ni-P alloy was deposited on commercial pure aluminium with different nickel source-reducing species ratios. Deposition time was fixed as two hours. The deposits were characterised for changes in morphology and crystallinity. It was observed that increase in nickel source to reducing species ratio produced a deposit with reduced mean nodule size. Also, nodule size distribution was narrow. Deposits with increased ratio showed higher levels of crystallinity. © (2014) Trans Tech Publications, Switzerland.Item Classification of tidal inlets along the central west coast of India(Elsevier Ltd, 2015) Mendi, M.; Reddy, N.A.; Rao, S.; Seelam, J.K.Tidal inlets along the Maharashtra coast on the central west coast of India were classified according to three methods available in the literature. Two classification methods viz., (i) Hydrodynamic classification (Hayes, 1979) and (ii) Classification based on dimensionless parameters (Vu, 2013) used for the classification are compared with the morphological classification of de Vriend et al., (1999). The hydrodynamic classification of Tidal inlets along Maharashtra coast is carried out considering mean annual significant wave height. The classification is also extended considering significant wave heights obtained for South-West monsoon, North-East monsoon and Fair Weather seasons. It has been observed that 74% of the inlets are tide dominated as per morphological classification whereas considering annual mean wave heights in Vu (2013) method, 67% of the inlets are wave dominated. © 2015 The Authors. Published by Elsevier Ltd.Item Ultrasound assisted Synthesis of Poly (styrene-Co-methylmethacrylate)-HNT's Nanocomposites by In-Situ Emulsion Copolymerization and its Characterization(Elsevier Ltd, 2017) Buruga, K.; Kalathi, J.T.Poly (styrene-co-methylmethacrylate)-HNT nanocomposites have been successfully synthesized by ultrasound assisted emulsion copolymerization without modification of HNT's. The key parameters that affect the stability of the emulsion and hence the properties of the resulting nanocomposites are sonication time and clay loading. The effectsof these parameters on the process were investigated in this study. Thesynthesized nanocomposites were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform and infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC) to investigatemorphology and thermal stability. The embodiment of the HNTs into the copolymer matrix was confirmed by FTIR, and XRD analyses positively delineated the complete exfoliation of HNTs into the copolymer matrix on sonication for 60 min. SEM analyses revealed homogenous dispersion of HNTs into the copolymer matrix and DSC analysis showed significant improvement in glass transition temperature (Tg)of composites upto 2 weight% of HNT loading and any further loading of HNT resulted in decrease in Tg.Zeta size and zeta potential analyses confirmed the particles were in nanoscale and possessed good stability respectively. This sonochemical route of preparation proves to be a promising way to accomplish nanocomposites synthesis with insitu polymerisation and to obtain better dispersion of particles in resulting composites. © 2017 Elsevier Ltd.Item Preparation and characterization of flexible PVDF based polymer film for energy harvesting applications(Elsevier Ltd, 2019) Naik, R.; Rao, S.T.In this work, Zirconium oxide based PVDF nanocomposite films are fabricated by using solution casting method with varying zirconium oxide fractions (0, 1, 5 wt%). The crystalline structure of prepared nanocomposite films is studied by X-Ray diffraction (X-RD) and FTIR methods. To check surface morphology, SEM study is carried out. From this study, it is observed that zirconium filler is well dispersed in the PVDF matrix. The piezoelectric performance of the prepared film is analyzed. From this analysis, maximum output voltage of 0.61V is observed during mechanically finger tapping and releasing condition for 5% of zirconium filler content film. © 2019 Elsevier Ltd. All rights reserved.Item Electroslag remelting experiments have been carried out on En 24 steel using two slag compositions in indigeneously constructed 350 KVA DC and 50 KVA AC ESR units. Detailed quantitative characterisation of the inclusions of different types has been carried out using Quantimet Image Analyser. The inclusion content in terms of volume fraction and density (No/mm2) and their size distribution in the refined ingot and the unrefined steel have been assessed. The chemical composition of selected inclusions has been established by electron probe microanalyser (EPMA). These studies are supplemented by scanning electron microscopy on typical fractured specimens. The present study shows that the DC reverse polarity mode of melting using a slag with higher silica content (10 wt%) offers the best conditions with particular reference to removal of inclusions and modification of inclusion morphology as compared to the ingots produced by DC straight polarity and AC modes of melting.(Studies on inclusion characterization in electroslag refined En24 steel) Udupa, K.R.; Subramanian, S.; Sastry, D.H.; Iyengar, G.N.K.1994Item Ductile cast iron samples were austenitized at 927 °C and subsequently austempered for 30 minutes, 1 hour, and 2 hours at 260 °C, 288 °C, 316 °C, 343 °C, 371 °C, and 399 °C. These were subjected to a plane strain fracture toughness test. Fracture toughness was found to initially increase with austempering temperature, reach a maximum, and then decrease with further rise in temperature. The results of the fracture toughness study and fractographic examination were correlated with microstructural features such as bainite morphology, the volume fraction of retained austenite, and its carbon content. It was found that fracture toughness was maximized when the microstructure consisted of lower bainite with about 30 vol pet retained austenite containing more than 1.8 wt pet carbon. A theoretical model was developed, which could explain the observed variation in fracture toughness with austempering temperature in terms of microstructural features such as the width of the ferrite blades and retained austenite content. A plot of KIC2 against ?? (X?C?)1/2 resulted in a straight line, as predicted by the model.(Minerals, Metals and Materials Society, Dependence of Fracture Toughness of Austempered Ductile Iron on Austempering Temperature) Prasad Rao, P.; Putatunda, S.K.1998Item For successful modelling of the solidification process, a reliable heat transfer boundary condition data is required. These boundary conditions are significantly influenced by the casting and mould parameters. In the present work, the effect of sodium modification melt treatment on casting/chill interfacial heat transfer during upward solidification of an Al-13% Si alloy against metallic chills is investigated using thermal analysis and inverse modelling techniques. In the presence of chills, modification melt treatment resulted in an increase in the cooling rate of the solidifying casting near the casting/chill interfacial region. The corresponding interfacial heat flux transients and electrical conductivities are also found to be higher. This is attributed to (i) improvement in the casting/chill interfacial thermal contact condition brought about by the decrease in the surface tension of the liquid metal on addition of sodium and (ii) increase in the electronic heat conduction in the initial solidified shell due to change in the morphology of silicon from a acicular type to a fine fibrous structure and increase in the ratio of the modification rating to the secondary dendrite arm spacing. © 2003 Elsevier B.V. All rights reserved.(Elsevier BV, Effect of modification melt treatment on casting/chill interfacial heat transfer and electrical conductivity of Al-13% Si alloy) Prabhu, K.; Ravishankar, B.N.2003Item Synthesis, characterization & impedance studies of some new nano filtration membranes(Trans Tech Publications Ltd ttp@transtec.ch, 2010) Padaki, M.; Hegde, C.; Isloor, A.M.In the recent years membrane technology has gained significant attention from polymer chemists all around the world due to their attractive features such as efficiency, low costs, low energy costs and as effective solutions to longstanding problems in the chemical industries. Membrane technologies have been widely applied in the separation of liquids and even gases. Many separation problems can be solved economically by nanofiltration alone or in combination with other separation processes. This study aimed to synthesize polysulfone based nanofiltration membranes using DIPS (diffusion induced phase separation) technique. Newly synthesized polymer membranes were subjected to Infra red spectral and water uptake studies. Membranes were also characterized using electrochemical spectroscopy for their proton conducting property. Their surface morphology is visualized by SEM. © (2010) Trans Tech Publications.