Sanjeev Singh

Dip-coated thin-film polycarbonate optical waveguides.

We report on our systematic and detailed study of fabrication and characterization of polycarbonate thin-film optical waveguides. Various waveguide properties, such as refractive index, optical loss, waveguide thickness, dispersion as a function of temperature of waveguides and substrates, and the effect of thickness gradient on optical guiding losses, have been reported. A comparative study of the properties of waveguides fabricated with dioxane and tetrahydrofuran as solvents is also presented.

Optimization of waveguide parameters of bisphenol A polycarbonate

Abstract We report here the observations made on dip coated bisphenol A polycarbonate thin films using integrated optic (IO) technique for parameters like refractive index, propagation loss and depth. The effect of temperature on these films was also observed for physical aging. Polycarbonate synthesized as planar optical waveguide exhibits low optical attenuation ( −1 ), having refractive index 1.590 and excellent transmission (80–95%) in the wavelength range (350–650 nm), which make this polymer promising for integrated optical devices.

A cryptographic model based on logistic map and a 3-D matrix

A new data encryption scheme is proposed based on the position substitution, shuffling and a diffusion process. The algorithm searches for the position of a text symbol in randomly generated 3-D matrix and subsequently replaces the symbol. The positions in matrix are shuffled in a retraceable manner depending upon the encryption key. Further, the substituted positions are diffused so that all the cipher text get affected even if a single symbol is changed. The system uses a Logistic map for matrix generation and position shuffling. The algorithm also checks the integrity of cipher text by including its parity in encrypted form. As the system includes substitution, permutation and diffusion, high level of cryptographic complexity is achieved in cipher text. The proposed method is key sensitive output cipher text is random in nature and has avalanche effect. The key length chosen is sufficient to resist a brute force attack. The cryptographic model as a whole demonstrate remarkable resistance to statistical attacks which is a key feature. Detailed runtime comparison with different known cryptographic systems is given.

Intertwining logistic map and Cellular Automata based color image encryption model

In this paper a color image encryption involving pixel confusion and diffusion governed by three different series generated by intertwining logistic map is proposed. This symmetric encryption model completes in two steps. First, the original image pixels are xor-ed with randomly generated data having values between 0 and 255. The xor-ed data is permuted by a shuffling engine. Secondly, diffusion of the permuted data is achieved by the help of Elementary Cellular Automata based diffusion mechanism. The decoding of the original information is not possible in the absence of knowledge of appropriate rules of the cellular automata and their order of use. The experimental results demonstrated outstanding performance for various tests conducted. Brute force resistance, larger key space, and good resistance against statistical and differential attacks comes out to be key features of the algorithm.

Nanoscale-RingFET: An Analytical Drain Current Model Including SCEs

In this paper, using a 2-D Poisson equation (in cylindrical coordinates), an analytical drain current model of a nanoscale RingFET architecture has been developed for the first time. Major short-channel effects, such as channel length modulation, velocity scattering, and drain-induced barrier lowering, are taken under consideration while developing the model. A bandgap narrowing model has been employed to investigate the impact of higher channel doping. The modeled results of the surface potential, electric field, threshold voltage (Vth), subthreshold slope, and drain current have been verified by comparing with those of the ATLAS 3-D device simulation. The influence of the drain radius and position of the source/drain regions on the electrical characteristics of the device has also been demonstrated.

Sub-threshold Drain Current model of Double Gate RingFET (DG-RingFET) Architecture: An Analog and Linearity Performance Investigation for RFIC Design

ABSTRACT In the present work, impact of Double Gate RingFET (DG-RingFET) has been investigated for better gate control and suppressed Short Channel Effects (SCEs) using ATLAS 3D device simulator. The analog performance metrics explored in this paper are drain current (Ids − Vgs), trans-conductance (gm), device efficiency (gm/Ids), and early voltage (Vea). In addition to this linearity behaviour of DG-RingFET has been investigated in terms of third-order voltage intercept point (VIP3), third-order current intercept point (IIP3), third-order inter modulation distortion (IMD3) and results are also compared with the single gate architecture. The two-dimensional analytical model for DG-RingFET architecture has also been developed in this paper using parabolic approach. Moreover, the impact of technology variations like drain radii and position of drain, i.e. inside or outside the channel ring on the performance of DG-RingFET architecture has also been assessed.

Supracardiac Total Anomalous Pulmonary Venous Connection with Severe Rheumatic Mitral Valve Disease

Abstract  A rare association of supracardiac total anomalous pulmonary venous connection (TAPVC) along with severe rheumatic mitral regurgitation is presented. The patient, a 28‐year‐old female, underwent successful repair of the TAPVC along with pericardial patch closure of the atrial septal defect and replacement of the mitral valve with a mechanical prosthesis. (J Card Surg 2011;26:526‐528)