OALib Journal期刊

ISSN: 2333-9721




2019 ( 15 )

2018 ( 126 )

2017 ( 109 )

2016 ( 247 )


匹配条件: “Kumar Sandeep” ,找到相关结果约21809条。
On Secure Digital Image Watermarking Techniques  [PDF]
Manjit Thapa, Sandeep Kumar Sood
Journal of Information Security (JIS) , 2011, DOI: 10.4236/jis.2011.24017
Abstract: Digital watermarking is used to hide the information inside a signal, which can not be easily extracted by the third party. Its widely used application is copyright protection of digital information. It is different from the encryption in the sense that it allows the user to access, view and interpret the signal but protect the ownership of the content. One of the current research areas is to protect digital watermark inside the information so that ownership of the information cannot be claimed by third party. With a lot of information available on various search engines, to protect the ownership of information is a crucial area of research. In latest years, several digital watermarking techniques are presented based on discrete cosine transform (DCT), discrete wavelets transform (DWT) and discrete fourier transforms (DFT). In this paper, we propose an algorithm for digital image watermarking technique based on singular value decomposition; both of the L and U components are explored for watermarking algorithm. This technique refers to the watermark embedding algorithm and watermark extracting algorithm. The experimental results prove that the quality of the watermarked image is excellent and there is strong resistant against many geometrical attacks.
Voltage Controlled Ring Oscillator Design with Novel 3 Transistors XNOR/XOR Gates  [PDF]
Manoj Kumar, Sandeep Kumar Arya, Sujata Pandey
Circuits and Systems (CS) , 2011, DOI: 10.4236/cs.2011.23027
Abstract: In present work, improved designs for voltage controlled ring oscillators (VCO) using three transistors XNOR/XOR gates have been presented. Supply voltage has been varied from [1.8 - 1.2] V in proposed designs. In first method, the VCO design using three XNOR delay cells shows frequency variation of [1.900 - 0.964] GHz with [279.429 - 16.515] µW power consumption variation. VCO designed with five XNOR delay cells shows frequency variation of [1.152 - 0.575] GHz with varying power consumption of [465.715 - 27.526] µW. In the second method VCO having three XOR stages shows frequency variation [1.9176 - 1.029] GHz with power consumption variation from [296.393 - 19.051] µW. A five stage XOR based VCO design shows frequency variation [1.049 - 0.565] GHz with power consumption variation from [493.989 - 31.753] µW. Simulations have been performed by using SPICE based on TSMC 0.18µm CMOS technology. Power consumption and output frequency range of proposed VCOs have been compared with earlier reported circuits and proposed circuit’s shows improved performance.
Indian Streams Research Journal , 2013,
Abstract: The main objective of this study was to see the impact of some variables namely Sex, Locality and Family background of college students on Perceived Loneliness. Normative Survey method was adopted to conduct the study. Sampling was done randomly and data was collected from 300 College students of Puducherry region with the help of Perceived Loneliness Scale having a five-point rating scale. The t-ratios calculated between the Mean values of different categories of college students indicated that the Location did not have any significant effect on Perceived Loneliness but Sex and Family Background have significant effect on it.
Reputation System in Peer-To-Peer Network: Design and Classification
Sandeep Kumar
Journal of Global Research in Computer Science , 2011,
Abstract: Peer-to-Peer (P2P) applications have recently seen an enormous success and have reached millions of users. The main reason of this success is the anonymity the users enjoy. However, as recent experiences with P2P networks show, this anonymity offers an opportunity to exploit the network like free-rider, virus spread, malicious file spread etc. The problem of securing hosts on P2P network while keeping the openness of the system has been studied extensively over last couple of years but still there are various issues on it. Reputation and incentive are two traditional systems to deal various problems in the Peer-to-Peer network. In this paper we define reputation system and give reputation system’s design consideration and classification used to create an efficient reputation system that can handle various P2P security issues like free-rider problem, DDoS attack.
A CAS Approach to Handle the Anisotropic Hooke’s Law for Cancellous Bone and Wood
Sandeep Kumar
Chinese Journal of Engineering , 2014, DOI: 10.1155/2014/487314
Abstract: The present research entirely relies on the Computer Algebric Systems (CAS) to develop techniques for the data analysis of the sets of elastic constant data measurements. In particular, this study deals with the development of some appropriate programming codes that favor the data analysis of known values of elastic constants for cancellous bone, hardwoods, and softwood species. More precisely, a “Mathematica” code, which has an ability to unfold a fourth-order elasticity tensor is discussed. Also, an effort towards the fabrication of an appropriate “MAPLE” code has been exposed, that can calculate not only the eigenvalues and eigenvectors for cancellous bone, hardwoods, and softwood species, but also computes the nominal average of eigenvectors, average eigenvectors, average eigenvalues, and the average elasticity matrices for these materials. Further, using such a MAPLE code, the histograms corresponding to average elasticity matrices of 15 hardwood species have been plotted and the graphs for I, II, III, IV, V, and VI eigenvalues of each hardwood species against their apparent densities are also drawn. 1. Introduction The study of material symmetry of 3-dimensional space is of great interest due to having crucial theoretical as well as practical significance. This is because a symmetrical space includes crystals and all homogeneous fields without exceptions: electric, magnetic, gravitational, and so forth. The variation of material properties with respect to direction at a stagnant point in a material is called material symmetry; for instance, if the material properties are same in all directions at some fixed point, they are called isotropic, whereas if the material properties show variation at the same point, they are called anisotropic [1]. Of course, the familiarity with material symmetries is the best way to categorize the materials. However, according to [2], many materials are anisotropic and inhomogeneous due to the varying composition of their constituents. In such materials, it becomes ticklish to identify the symmetries or more particularly, the elastic symmetries. The variable composition method to identify material’s elastic symmetry becomes complicated and hence to overcome this difficulty, an approach is developed by [3], called “averaging anisotropic elastic constant data.” In this approach, the identification of elastic symmetries and method of variable composition are analyzed separately. With the aid of this fabulous approach, a sheer volume of research towards material symmetry has been put forward by various researchers, for
Sandeep Kumar,Nitin Kumar
International Research Journal of Pharmacy , 2013,
Abstract: In present work, Ligand butanone thiosemicarbazone and their 11 complexes of the type ML2X2, ML2X’, where M = Cu(II), Cd(II), Co(II), Zn(II), Hg(II); L = butanone thiosemicarbazone; X = Cl, NO3 or CH3COO; X’ = SO4 have been synthesized and characterized with the help of infra-red and ultra-violet spectroscopy. The spectral data revealed that the thiosemicarbazone act as bidentate ligand, making use of thionic sulphur and the azomethine nitrogen atom for co-ordination to the central metal atom. All the compounds have been screened for their antibacterial activity against Gram positive bacteria Staphylococcus aureus, Staphylococcus epidermidis and Gram negative bacteria Escherichia coli and Pseudomonas aeruginosa. Some of complexes exhibited appreciable activity.
Generalized Abel Inversion Using Homotopy Perturbation Method  [PDF]
Sunil Kumar, Om P. Singh, Sandeep Dixit
Applied Mathematics (AM) , 2011, DOI: 10.4236/am.2011.22029
Abstract: Many problems in physics like reconstruction of the radially distributed emissivity from the line-of-sight projected intensity, the 3-D image reconstruction from cone beam projections in computerized tomography, etc. lead naturally, in the case of radial symmetry, to the study of Abel’s type integral equation. Obtaining the physically relevant quantity from the measured one requires, therefore the inversion of the Abel’s integral equation. The aim of this letter is to present a user friendly algorithm to invert generalized Abel integral equation by using homotopy perturbation method. The stability of the algorithm is analysed. The validity and applicability of this powerful technique is illustrated through various particular cases which demonstrate its efficiency and simplicity in solving these types of integral equations.
Preparation and Characterization of TiO2 and SiO2Thin Films  [PDF]
Davinder Rathee, Sandeep K. Arya, Mukesh Kumar
World Journal of Nano Science and Engineering (WJNSE) , 2011, DOI: 10.4236/wjnse.2011.13013
Abstract: Although scaling will continue for couple of decades but device geometries reaches to atomic size and limitation of quantum mechanical physical boundaries. To address these problems there is need of innovation in material science & engineering, device structure, and new nano devices based on different principle of physics. So TiO2 thin films have been grown on well clean N-type silicon substrates via a sol–gel spin coating method. MOS capacitor were fabricated and characterized with SiO2 and TiO2 as dielectric material on N-type silicon wafer. The thickness was measured by stylus profiler and found to be 510 Å and 528 Å for SiO2 and TiO2 respectively. Some of the material parameters were found from the measured Capacitance -Voltage (C-V) curve obtained by SUPREM-III (Stanford University Process Engineering Model Version 0-83) for SiO2 and C-V Keithly 590 analyzer for TiO2 thin films. The result shows that obtained TiO2 film present a dielectric constant of approximately 80. The refractive index was found to be 2.4 and optical constant was 5.43 obtained from Ellipsometry. Band gap 3.6 eV of TiO2 was calculated by spectrophotometer and Surface morphology was obtained using Scanning Electron Microscope (SEM-JEOL) micrograph. The aluminum (Al) metal was deposited by the thermal evaporation system on the back side of the sample for the ohmic contact. Analysis shows that TiO2 may be acceptable as a viable substitute for high k dielectric in order to prevent the tunneling current problems.
Studies on antibacterial activity and biochemical/biophysical properties of phytocystatin purified from Catharanthus roseus (Madagascar Periwinkle): an evergreen subshrub commonly found in district bijnor (U.P.)  [PDF]
Garima Sharma, Mukesh Kumar, Sandeep Sharma
Advances in Bioscience and Biotechnology (ABB) , 2011, DOI: 10.4236/abb.2011.26057
Abstract: In the present study two phytocystatins (thiol protease inhibitors) have been isolated and purified to homogeneity form Catharanthus roseusby a simple two step procedure using ammonium sulphate fractionation and gelfiltration chromatography on Sephacryl- 100HR.The two inhibitors were named as CRCI and CRCII (Catharanthus roseuscystatin I and II). CRCI and CRCII were purified with a fold purification of 1333.3, 1348.5 and percent yield of 18.18 and 16.35% respectively. The molecular weight of purified phytocystatins were 19.1 kDa and 16.9 kDa respectively, as determined by SDS-PAGE and mass spectrometry. Effect of denaturants like ureaon CRCI and II was analysed by Fluorescence spectroscopy. Results suggest an unfolding of CRCI and II. FTIR results show that structurally CRCI is different from CRCII. Hydrophobic interactions are observed over a longer timescale (5 - 150 min). Furthermore, fluorescence spectroscopy results show quenching of fluorescence intensity of CRC I and II, although to different extent, due to perturbations of the environment of aromatic residues in the protein. Both the cystatins showed strong inhibitory/antibacterial activity against E. coliand S. aureus
Thymosin Beta 4 Prevents Oxidative Stress by Targeting Antioxidant and Anti-Apoptotic Genes in Cardiac Fibroblasts
Sandeep Kumar, Sudhiranjan Gupta
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0026912
Abstract: Rationale Thymosin beta-4 (Tβ4) is a ubiquitous protein with diverse functions relating to cell proliferation and differentiation that promotes wound healing and modulates inflammatory responses. The effecter molecules targeted by Tβ4 for cardiac protection remains unknown. The purpose of this study is to determine the molecules targeted by Tβ4 that mediate cardio-protection under oxidative stress. Methods Rat neonatal fibroblasts cells were exposed to hydrogen peroxide (H2O2) in presence and absence of Tβ4 and expression of antioxidant, apoptotic and pro-fibrotic genes was evaluated by quantitative real-time PCR and western blotting. Reactive oxygen species (ROS) levels were estimated by DCF-DA using fluorescent microscopy and fluorimetry. Selected antioxidant and antiapoptotic genes were silenced by siRNA transfections in cardiac fibroblasts and the effect of Tβ4 on H2O2-induced profibrotic events was evaluated. Results Pre-treatment with Tβ4 resulted in reduction of the intracellular ROS levels induced by H2O2 in the cardiac fibroblasts. This was associated with an increased expression of antioxidant enzymes Cu/Zn superoxide dismutase (SOD) and catalase and reduction of Bax/Bcl2 ratio. Tβ4 treatment reduced the expression of pro-fibrotic genes [connective tissue growth factor (CTGF), collagen type-1 (Col-I) and collagen type-3 (Col-III)] in the cardiac fibroblasts. Silencing of Cu/Zn-SOD and catalase gene triggered apoptotic cell death in the cardiac fibroblasts, which was prevented by treatment with Tβ4. Conclusion This is the first report that exhibits the targeted molecules modulated by Tβ4 under oxidative stress utilizing the cardiac fibroblasts. Tβ4 treatment prevented the profibrotic gene expression in the in vitro settings. Our findings indicate that Tβ4 selectively targets and upregulates catalase, Cu/Zn-SOD and Bcl2, thereby, preventing H2O2-induced profibrotic changes in the myocardium. Further studies are warranted to elucidate the signaling pathways involved in the cardio-protection afforded by Tβ4.

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